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Changes On Branch wal2
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Changes In Branch wal2 Excluding Merge-Ins

This is equivalent to a diff from 96c92aba to fdc0e148

2024-05-23
23:30
Fix the window-function group_concat() so that it returns an empty string if it has one or more empty string inputs. (check-in: 7fe11274 user: drh tags: branch-3.46)
14:58
Increase the version number to 3.47.0 to begin the next development cycle. (check-in: 20e228a2 user: drh tags: trunk)
14:09
Version 3.46.0 for the reuse-schema branch (Leaf check-in: 8f6b8594 user: drh tags: reuse-schema)
14:09
Version 3.46.0 for the bedrock branch (check-in: 483d112a user: drh tags: bedrock)
14:05
Version 3.46.0 for the wal2 branch. (Leaf check-in: fdc0e148 user: drh tags: wal2)
14:04
Version 3.46.0 for the begin-concurrent branch (check-in: e3f8c70e user: drh tags: begin-concurrent)
13:25
Version 3.46.0 (check-in: 96c92aba user: drh tags: trunk, release, major-release, version-3.46.0)
2024-05-21
17:37
Ensure an sqlite_dbdata cursor is properly reset before being used again, even if it has already encountered database corruption. (check-in: 3210e1ca user: dan tags: trunk)
15:20
Merge the latest trunk enhancements into the wal2 branch. (check-in: d4217d9f user: drh tags: wal2)

Changes to Makefile.in.

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# Statically linked extensions
#
TESTSRC += \
  $(TOP)/ext/expert/sqlite3expert.c \
  $(TOP)/ext/expert/test_expert.c \
  $(TOP)/ext/misc/amatch.c \

  $(TOP)/ext/misc/appendvfs.c \
  $(TOP)/ext/misc/basexx.c \
  $(TOP)/ext/misc/carray.c \
  $(TOP)/ext/misc/cksumvfs.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/csv.c \
  $(TOP)/ext/misc/decimal.c \







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# Statically linked extensions
#
TESTSRC += \
  $(TOP)/ext/expert/sqlite3expert.c \
  $(TOP)/ext/expert/test_expert.c \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/bgckpt.c \
  $(TOP)/ext/misc/appendvfs.c \
  $(TOP)/ext/misc/basexx.c \
  $(TOP)/ext/misc/carray.c \
  $(TOP)/ext/misc/cksumvfs.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/csv.c \
  $(TOP)/ext/misc/decimal.c \

Changes to Makefile.msc.

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#
TESTEXT = \
  $(TOP)\ext\expert\sqlite3expert.c \
  $(TOP)\ext\expert\test_expert.c \
  $(TOP)\ext\misc\amatch.c \
  $(TOP)\ext\misc\appendvfs.c \
  $(TOP)\ext\misc\basexx.c \

  $(TOP)\ext\misc\carray.c \
  $(TOP)\ext\misc\cksumvfs.c \
  $(TOP)\ext\misc\closure.c \
  $(TOP)\ext\misc\csv.c \
  $(TOP)\ext\misc\decimal.c \
  $(TOP)\ext\misc\eval.c \
  $(TOP)\ext\misc\explain.c \







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#
TESTEXT = \
  $(TOP)\ext\expert\sqlite3expert.c \
  $(TOP)\ext\expert\test_expert.c \
  $(TOP)\ext\misc\amatch.c \
  $(TOP)\ext\misc\appendvfs.c \
  $(TOP)\ext\misc\basexx.c \
  $(TOP)\ext\misc\bgckpt.c \
  $(TOP)\ext\misc\carray.c \
  $(TOP)\ext\misc\cksumvfs.c \
  $(TOP)\ext\misc\closure.c \
  $(TOP)\ext\misc\csv.c \
  $(TOP)\ext\misc\decimal.c \
  $(TOP)\ext\misc\eval.c \
  $(TOP)\ext\misc\explain.c \

Added doc/wal2.md.





































































































































































































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Wal2 Mode Notes
===============

## Activating/Deactivating Wal2 Mode

"Wal2" mode is very similar to "wal" mode. To change a database to wal2 mode,
use the command:

>
     PRAGMA journal_mode = wal2;

It is not possible to change a database directly from "wal" mode to "wal2"
mode. Instead, it must first be changed to rollback mode. So, to change a wal
mode database to wal2 mode, the following two commands may be used:

>
     PRAGMA journal_mode = delete;
     PRAGMA journal_mode = wal2;

A database in wal2 mode may only be accessed by versions of SQLite compiled
from this branch. Attempting to use any other version of SQLite results in an
SQLITE_NOTADB error. A wal2 mode database may be changed back to rollback mode
(making it accessible by all versions of SQLite) using:

>
     PRAGMA journal_mode = delete;

## The Advantage of Wal2 Mode

In legacy wal mode, when a writer writes data to the database, it doesn't
modify the database file directly. Instead, it appends new data to the
"<database>-wal" file. Readers read data from both the original database
file and the "<database>-wal" file. At some point, data is copied from the
"<database>-wal" file into the database file, after which the wal file can
be deleted or overwritten. Copying data from the wal file into the database
file is called a "checkpoint", and may be done explictly (either by "PRAGMA
wal_checkpoint" or sqlite3_wal_checkpoint_v2()), or
automatically (by configuring "PRAGMA wal_autocheckpoint" - this is the
default).

Checkpointers do not block writers, and writers do not block checkpointers.
However, if a writer writes to the database while a checkpoint is ongoing,
then the new data is appended to the end of the wal file. This means that,
even following the checkpoint, the wal file cannot be overwritten or deleted,
and so all subsequent transactions must also be appended to the wal file. The
work of the checkpointer is not wasted - SQLite remembers which parts of the
wal file have already been copied into the db file so that the next checkpoint
does not have to do so again - but it does mean that the wal file may grow
indefinitely if the checkpointer never gets a chance to finish without a
writer appending to the wal file. There are also circumstances in which
long-running readers may prevent a checkpointer from checkpointing the entire
wal file - also causing the wal file to grow indefinitely in a busy system.

Wal2 mode does not have this problem. In wal2 mode, wal files do not grow
indefinitely even if the checkpointer never has a chance to finish
uninterrupted.

In wal2 mode, the system uses two wal files instead of one. The files are named
"<database>-wal" and "<database>-wal2", where "<database>" is of
course the name of the database file. When data is written to the database, the
writer begins by appending the new data to the first wal file. Once the first
wal file has grown large enough, writers switch to appending data to the second
wal file. At this point the first wal file can be checkpointed (after which it
can be overwritten). Then, once the second wal file has grown large enough and
the first wal file has been checkpointed, writers switch back to the first wal
file. And so on.

## Application Programming

From the point of view of the user, the main differences between wal and 
wal2 mode are to do with checkpointing:

  * In wal mode, a checkpoint may be attempted at any time. In wal2 
    mode, the checkpointer has to wait until writers have switched 
    to the "other" wal file before a checkpoint can take place.

  * In wal mode, the wal-hook (callback registered using
    sqlite3_wal_hook()) is invoked after a transaction is committed
    with the total number of pages in the wal file as an argument. In wal2
    mode, the argument is either the total number of uncheckpointed pages in
    both wal files, or - if the "other" wal file is empty or already
    checkpointed - 0.

Clients are recommended to use the same strategies for checkpointing wal2 mode
databases as for wal databases - by registering a wal-hook using
sqlite3_wal_hook() and attempting a checkpoint when the parameter
exceeds a certain threshold.

However, it should be noted that although the wal-hook is invoked after each
transaction is committed to disk and database locks released, it is still
invoked from within the sqlite3_step() call used to execute the "COMMIT"
command. In BEGIN CONCURRENT systems, where the "COMMIT" is often protected by
an application mutex, this may reduce concurrency. In such systems, instead of
executing a checkpoint from within the wal-hook, a thread might defer this
action until after the application mutex has been released.


Added ext/misc/bgckpt.c.









































































































































































































































































































































































































































































































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/*
** 2017-10-11
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
*/

#if !defined(SQLITE_TEST) || defined(SQLITE_OS_UNIX)

#include "sqlite3.h"
#include <string.h>
#include <pthread.h>

/*
** API declarations.
*/
typedef struct Checkpointer Checkpointer;
int sqlite3_bgckpt_create(const char *zFilename, Checkpointer **pp);
int sqlite3_bgckpt_checkpoint(Checkpointer *p, int bBlock);
void sqlite3_bgckpt_destroy(Checkpointer *p);


struct Checkpointer {
  sqlite3 *db;                    /* Database handle */

  pthread_t thread;               /* Background thread */
  pthread_mutex_t mutex;
  pthread_cond_t cond;

  int rc;                         /* Error from "PRAGMA wal_checkpoint" */
  int bCkpt;                      /* True if checkpoint requested */
  int bExit;                      /* True if exit requested */
};

static void *bgckptThreadMain(void *pCtx){
  int rc = SQLITE_OK;
  Checkpointer *p = (Checkpointer*)pCtx;

  while( rc==SQLITE_OK ){
    int bExit;

    pthread_mutex_lock(&p->mutex);
    if( p->bCkpt==0 && p->bExit==0 ){
      pthread_cond_wait(&p->cond, &p->mutex);
    }
    p->bCkpt = 0;
    bExit = p->bExit;
    pthread_mutex_unlock(&p->mutex);

    if( bExit ) break;
    rc = sqlite3_exec(p->db, "PRAGMA wal_checkpoint", 0, 0, 0);
    if( rc==SQLITE_BUSY ){
      rc = SQLITE_OK;
    }
  }

  pthread_mutex_lock(&p->mutex);
  p->rc = rc;
  pthread_mutex_unlock(&p->mutex);
  return 0;
}

void sqlite3_bgckpt_destroy(Checkpointer *p){
  if( p ){
    void *ret = 0;

    /* Signal the background thread to exit */
    pthread_mutex_lock(&p->mutex);
    p->bExit = 1;
    pthread_cond_broadcast(&p->cond);
    pthread_mutex_unlock(&p->mutex);

    pthread_join(p->thread, &ret);
    sqlite3_close(p->db);
    sqlite3_free(p);
  }
}


int sqlite3_bgckpt_create(const char *zFilename, Checkpointer **pp){
  Checkpointer *pNew = 0;
  int rc;

  pNew = (Checkpointer*)sqlite3_malloc(sizeof(Checkpointer));
  if( pNew==0 ){
    rc = SQLITE_NOMEM;
  }else{
    memset(pNew, 0, sizeof(Checkpointer));
    rc = sqlite3_open(zFilename, &pNew->db);
  }

  if( rc==SQLITE_OK ){
    pthread_mutex_init(&pNew->mutex, 0);
    pthread_cond_init(&pNew->cond, 0);
    pthread_create(&pNew->thread, 0, bgckptThreadMain, (void*)pNew);
  }

  if( rc!=SQLITE_OK ){
    sqlite3_bgckpt_destroy(pNew);
    pNew = 0;
  }
  *pp = pNew;
  return rc;
}

int sqlite3_bgckpt_checkpoint(Checkpointer *p, int bBlock){
  int rc;
  pthread_mutex_lock(&p->mutex);
  rc = p->rc;
  if( rc==SQLITE_OK ){
    p->bCkpt = 1;
    pthread_cond_broadcast(&p->cond);
  }
  pthread_mutex_unlock(&p->mutex);
  return rc;
}

#ifdef SQLITE_TEST

#if defined(INCLUDE_SQLITE_TCL_H)
#  include "sqlite_tcl.h"
#else
#  include "tcl.h"
#  ifndef SQLITE_TCLAPI
#    define SQLITE_TCLAPI
#  endif
#endif

const char *sqlite3ErrName(int rc);

static void SQLITE_TCLAPI bgckpt_del(void * clientData){
  Checkpointer *pCkpt = (Checkpointer*)clientData;
  sqlite3_bgckpt_destroy(pCkpt);
}

/*
** Tclcmd: $ckpt SUBCMD ...
*/
static int SQLITE_TCLAPI bgckpt_obj_cmd(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  Checkpointer *pCkpt = (Checkpointer*)clientData;
  const char *aCmd[] = { "checkpoint", "destroy", 0 };
  int iCmd;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCMD ...");
    return TCL_ERROR;
  }

  if( Tcl_GetIndexFromObj(interp, objv[1], aCmd, "sub-command", 0, &iCmd) ){
    return TCL_ERROR;
  }

  switch( iCmd ){
    case 0: {
      int rc;
      int bBlock = 0;

      if( objc>3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "?BLOCKING?");
        return TCL_ERROR;
      }
      if( objc==3 && Tcl_GetBooleanFromObj(interp, objv[2], &bBlock) ){
        return TCL_ERROR;
      }

      rc = sqlite3_bgckpt_checkpoint(pCkpt, bBlock);
      if( rc!=SQLITE_OK ){
        Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
        return TCL_ERROR;
      }
      break;
    }

    case 1: {
      Tcl_DeleteCommand(interp, Tcl_GetString(objv[0]));
      break;
    }
  }

  return TCL_OK;
}

/*
** Tclcmd: bgckpt CMDNAME FILENAME
*/
static int SQLITE_TCLAPI bgckpt_cmd(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  const char *zCmd;
  const char *zFilename;
  int rc;
  Checkpointer *pCkpt;

  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "CMDNAME FILENAME");
    return TCL_ERROR;
  }
  zCmd = Tcl_GetString(objv[1]);
  zFilename = Tcl_GetString(objv[2]);

  rc = sqlite3_bgckpt_create(zFilename, &pCkpt);
  if( rc!=SQLITE_OK ){
    Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
    return TCL_ERROR;
  }

  Tcl_CreateObjCommand(interp, zCmd, bgckpt_obj_cmd, (void*)pCkpt, bgckpt_del);
  Tcl_SetObjResult(interp, objv[1]);
  return TCL_OK;
}

int Bgckpt_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "bgckpt", bgckpt_cmd, 0, 0);
  return TCL_OK;
}
#endif   /* SQLITE_TEST */

#else
#if defined(INCLUDE_SQLITE_TCL_H)
#  include "sqlite_tcl.h"
#else
#  include "tcl.h"
#  ifndef SQLITE_TCLAPI
#    define SQLITE_TCLAPI
#  endif
#endif
int Bgckpt_Init(Tcl_Interp *interp){ return TCL_OK; }
#endif

Added ext/wasm/EXPORTED_FUNCTIONS.fiddle.















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_fiddle_exec
_fiddle_interrupt
_fiddle_experiment
_fiddle_the_db
_fiddle_db_arg
_fiddle_db_filename
_fiddle_reset_db

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_fiddle_db_arg
_fiddle_db_filename
_fiddle_exec
_fiddle_experiment
_fiddle_interrupt
_fiddle_main
_fiddle_reset_db
_fiddle_db_handle
_fiddle_db_vfs
_fiddle_export_db
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Changes to ext/wasm/api/EXPORTED_FUNCTIONS.sqlite3-api.

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_malloc
_free
_realloc
_sqlite3_aggregate_context
_sqlite3_auto_extension
_sqlite3_bind_blob
_sqlite3_bind_double
_sqlite3_bind_int
_sqlite3_bind_int64
_sqlite3_bind_null
_sqlite3_bind_parameter_count
_sqlite3_bind_parameter_index
_sqlite3_bind_pointer
_sqlite3_bind_text
_sqlite3_busy_handler
_sqlite3_busy_timeout
_sqlite3_cancel_auto_extension
_sqlite3_changes
_sqlite3_changes64
_sqlite3_clear_bindings
_sqlite3_close_v2
_sqlite3_collation_needed
_sqlite3_column_blob
_sqlite3_column_bytes
_sqlite3_column_count
_sqlite3_column_count
_sqlite3_column_double
_sqlite3_column_int
_sqlite3_column_int64
_sqlite3_column_name
_sqlite3_column_text
_sqlite3_column_type
_sqlite3_column_value
_sqlite3_commit_hook
_sqlite3_compileoption_get
_sqlite3_compileoption_used
_sqlite3_complete
_sqlite3_context_db_handle
_sqlite3_create_collation
_sqlite3_create_collation_v2
_sqlite3_create_function
_sqlite3_create_function_v2
_sqlite3_create_module
_sqlite3_create_module_v2
_sqlite3_create_window_function
_sqlite3_data_count
_sqlite3_db_filename
_sqlite3_db_handle
_sqlite3_db_name
_sqlite3_db_status
_sqlite3_declare_vtab
_sqlite3_deserialize
_sqlite3_drop_modules
_sqlite3_errcode
_sqlite3_errmsg
_sqlite3_error_offset
_sqlite3_errstr
_sqlite3_exec
_sqlite3_expanded_sql
_sqlite3_extended_errcode
_sqlite3_extended_result_codes
_sqlite3_file_control
_sqlite3_finalize
_sqlite3_free
_sqlite3_get_auxdata
_sqlite3_get_autocommit
_sqlite3_initialize
_sqlite3_keyword_count
_sqlite3_keyword_name
_sqlite3_keyword_check
_sqlite3_last_insert_rowid
_sqlite3_libversion
_sqlite3_libversion_number
_sqlite3_limit
_sqlite3_malloc
_sqlite3_malloc64
_sqlite3_msize
_sqlite3_open
_sqlite3_open_v2
_sqlite3_overload_function
_sqlite3_prepare_v2
_sqlite3_prepare_v3
_sqlite3_preupdate_blobwrite
_sqlite3_preupdate_count
_sqlite3_preupdate_depth
_sqlite3_preupdate_hook
_sqlite3_preupdate_new
_sqlite3_preupdate_old
_sqlite3_progress_handler
_sqlite3_randomness
_sqlite3_realloc
_sqlite3_realloc64
_sqlite3_reset
_sqlite3_reset_auto_extension
_sqlite3_result_blob
_sqlite3_result_double
_sqlite3_result_error
_sqlite3_result_error_code
_sqlite3_result_error_nomem
_sqlite3_result_error_toobig
_sqlite3_result_int
_sqlite3_result_int64
_sqlite3_result_null
_sqlite3_result_pointer
_sqlite3_result_subtype
_sqlite3_result_text
_sqlite3_result_zeroblob
_sqlite3_result_zeroblob64
_sqlite3_rollback_hook
_sqlite3_serialize
_sqlite3_set_authorizer
_sqlite3_set_auxdata
_sqlite3_set_last_insert_rowid
_sqlite3_shutdown
_sqlite3_sourceid
_sqlite3_sql
_sqlite3_status
_sqlite3_status64
_sqlite3_step
_sqlite3_stmt_isexplain
_sqlite3_stmt_readonly
_sqlite3_stmt_status
_sqlite3_strglob
_sqlite3_stricmp
_sqlite3_strlike
_sqlite3_strnicmp
_sqlite3_table_column_metadata
_sqlite3_total_changes
_sqlite3_total_changes64
_sqlite3_trace_v2
_sqlite3_txn_state
_sqlite3_update_hook
_sqlite3_uri_boolean
_sqlite3_uri_int64
_sqlite3_uri_key
_sqlite3_uri_parameter
_sqlite3_user_data
_sqlite3_value_blob
_sqlite3_value_bytes
_sqlite3_value_double
_sqlite3_value_dup
_sqlite3_value_free
_sqlite3_value_frombind
_sqlite3_value_int
_sqlite3_value_int64
_sqlite3_value_nochange
_sqlite3_value_numeric_type
_sqlite3_value_pointer
_sqlite3_value_subtype
_sqlite3_value_text
_sqlite3_value_type
_sqlite3_vfs_find
_sqlite3_vfs_register
_sqlite3_vfs_unregister
_sqlite3_vtab_collation
_sqlite3_vtab_distinct
_sqlite3_vtab_in
_sqlite3_vtab_in_first
_sqlite3_vtab_in_next
_sqlite3_vtab_nochange
_sqlite3_vtab_on_conflict
_sqlite3_vtab_rhs_value
_sqlite3changegroup_add
_sqlite3changegroup_add_strm
_sqlite3changegroup_delete
_sqlite3changegroup_new
_sqlite3changegroup_output
_sqlite3changegroup_output_strm
_sqlite3changeset_apply
_sqlite3changeset_apply_strm
_sqlite3changeset_apply_v2
_sqlite3changeset_apply_v2_strm
_sqlite3changeset_concat
_sqlite3changeset_concat_strm
_sqlite3changeset_conflict
_sqlite3changeset_finalize
_sqlite3changeset_fk_conflicts
_sqlite3changeset_invert
_sqlite3changeset_invert_strm
_sqlite3changeset_new
_sqlite3changeset_next
_sqlite3changeset_old
_sqlite3changeset_op
_sqlite3changeset_pk
_sqlite3changeset_start
_sqlite3changeset_start_strm
_sqlite3changeset_start_v2
_sqlite3changeset_start_v2_strm
_sqlite3session_attach
_sqlite3session_changeset
_sqlite3session_changeset_size
_sqlite3session_changeset_strm
_sqlite3session_config
_sqlite3session_create
_sqlite3session_delete
_sqlite3session_diff
_sqlite3session_enable
_sqlite3session_indirect
_sqlite3session_isempty
_sqlite3session_memory_used
_sqlite3session_object_config
_sqlite3session_patchset
_sqlite3session_patchset_strm
_sqlite3session_table_filter
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_sqlite3_bind_double
_sqlite3_bind_int
_sqlite3_bind_int64
_sqlite3_bind_null
_sqlite3_bind_parameter_count
_sqlite3_bind_parameter_index

_sqlite3_bind_text



_sqlite3_changes
_sqlite3_changes64
_sqlite3_clear_bindings
_sqlite3_close_v2

_sqlite3_column_blob
_sqlite3_column_bytes
_sqlite3_column_count
_sqlite3_column_count
_sqlite3_column_double
_sqlite3_column_int
_sqlite3_column_int64
_sqlite3_column_name
_sqlite3_column_text
_sqlite3_column_type


_sqlite3_compileoption_get
_sqlite3_compileoption_used





_sqlite3_create_function_v2



_sqlite3_data_count
_sqlite3_db_filename

_sqlite3_db_name





_sqlite3_errmsg
_sqlite3_error_offset
_sqlite3_errstr
_sqlite3_exec
_sqlite3_expanded_sql
_sqlite3_extended_errcode
_sqlite3_extended_result_codes

_sqlite3_finalize
_sqlite3_initialize


_sqlite3_interrupt




_sqlite3_libversion
_sqlite3_libversion_number




_sqlite3_open
_sqlite3_open_v2

_sqlite3_prepare_v2
_sqlite3_prepare_v3










_sqlite3_reset

_sqlite3_result_blob
_sqlite3_result_double
_sqlite3_result_error
_sqlite3_result_error_code
_sqlite3_result_error_nomem
_sqlite3_result_error_toobig
_sqlite3_result_int

_sqlite3_result_null


_sqlite3_result_text








_sqlite3_sourceid
_sqlite3_sql


_sqlite3_step



_sqlite3_strglob

_sqlite3_strlike


_sqlite3_total_changes
_sqlite3_total_changes64








_sqlite3_value_blob
_sqlite3_value_bytes
_sqlite3_value_double









_sqlite3_value_text
_sqlite3_value_type
_sqlite3_vfs_find
_sqlite3_vfs_register
_sqlite3_wasm_db_error


_sqlite3_wasm_enum_json




_malloc































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Changes to ext/wasm/api/sqlite3-worker1-promiser.c-pp.js.

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//#ifnot omit-oo1
/*
  2022-08-24

  The author disclaims copyright to this source code.  In place of a
  legal notice, here is a blessing:

  *   May you do good and not evil.
<








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/*
  2022-08-24

  The author disclaims copyright to this source code.  In place of a
  legal notice, here is a blessing:

  *   May you do good and not evil.
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   config option may alternately be a function, in which case this
   function re-assigns this property with the result of calling that
   function, enabling delayed instantiation of a Worker.

   - `onready` (optional, but...): this callback is called with no
   arguments when the worker fires its initial
   'sqlite3-api'/'worker1-ready' message, which it does when
   sqlite3.initWorker1API() completes its initialization. This is the
   simplest way to tell the worker to kick off work at the earliest
   opportunity, and the only way to know when the worker module has
   completed loading. The irony of using a callback for this, instead
   of returning a promise from sqlite3Worker1Promiser() is not lost on
   the developers: see sqlite3Worker1Promiser.v2() which uses a
   Promise instead.

   - `onunhandled` (optional): a callback which gets passed the
   message event object for any worker.onmessage() events which
   are not handled by this proxy. Ideally that "should" never
   happen, as this proxy aims to handle all known message types.

   - `generateMessageId` (optional): a function which, when passed an







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   config option may alternately be a function, in which case this
   function re-assigns this property with the result of calling that
   function, enabling delayed instantiation of a Worker.

   - `onready` (optional, but...): this callback is called with no
   arguments when the worker fires its initial
   'sqlite3-api'/'worker1-ready' message, which it does when
   sqlite3.initWorker1API() completes its initialization. This is
   the simplest way to tell the worker to kick off work at the
   earliest opportunity.





   - `onunhandled` (optional): a callback which gets passed the
   message event object for any worker.onmessage() events which
   are not handled by this proxy. Ideally that "should" never
   happen, as this proxy aims to handle all known message types.

   - `generateMessageId` (optional): a function which, when passed an
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      columnNames: array}

   Where `typeString` is an internally-synthesized message type string
   used temporarily for worker message dispatching. It can be ignored
   by all client code except that which tests this API. The `row`
   property contains the row result in the form implied by the
   `rowMode` option (defaulting to `'array'`). The `rowNumber` is a
   1-based integer value incremented by 1 on each call into the
   callback.

   At the end of the result set, the same event is fired with
   (row=undefined, rowNumber=null) to indicate that
   the end of the result set has been reached. Note that the rows
   arrive via worker-posted messages, with all the implications
   of that.

   Notable shortcomings:

   - This API was not designed with ES6 modules in mind. Neither Firefox
     nor Safari support, as of March 2023, the {type:"module"} flag to the
     Worker constructor, so that particular usage is not something we're going
     to target for the time being:

     https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker
*/
globalThis.sqlite3Worker1Promiser = function callee(config = callee.defaultConfig){
  // Inspired by: https://stackoverflow.com/a/52439530
  if(1===arguments.length && 'function'===typeof arguments[0]){
    const f = config;
    config = Object.assign(Object.create(null), callee.defaultConfig);
    config.onready = f;
  }else{
    config = Object.assign(Object.create(null), callee.defaultConfig, config);







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      columnNames: array}

   Where `typeString` is an internally-synthesized message type string
   used temporarily for worker message dispatching. It can be ignored
   by all client code except that which tests this API. The `row`
   property contains the row result in the form implied by the
   `rowMode` option (defaulting to `'array'`). The `rowNumber` is a
   1-based integer value incremented by 1 on each call into th 
   callback.

   At the end of the result set, the same event is fired with
   (row=undefined, rowNumber=null) to indicate that
   the end of the result set has been reached. Note that the rows
   arrive via worker-posted messages, with all the implications
   of that.









*/
self.sqlite3Worker1Promiser = function callee(config = callee.defaultConfig){
  // Inspired by: https://stackoverflow.com/a/52439530
  if(1===arguments.length && 'function'===typeof arguments[0]){
    const f = config;
    config = Object.assign(Object.create(null), callee.defaultConfig);
    config.onready = f;
  }else{
    config = Object.assign(Object.create(null), callee.defaultConfig, config);
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  const genMsgId = config.generateMessageId || function(msg){
    return msg.type+'#'+(idTypeMap[msg.type] = (idTypeMap[msg.type]||0) + 1);
  };
  const toss = (...args)=>{throw new Error(args.join(' '))};
  if(!config.worker) config.worker = callee.defaultConfig.worker;
  if('function'===typeof config.worker) config.worker = config.worker();
  let dbId;
  let promiserFunc;
  config.worker.onmessage = function(ev){
    ev = ev.data;
    debug('worker1.onmessage',ev);
    let msgHandler = handlerMap[ev.messageId];
    if(!msgHandler){
      if(ev && 'sqlite3-api'===ev.type && 'worker1-ready'===ev.result) {
        /*fired one time when the Worker1 API initializes*/
        if(config.onready) config.onready(promiserFunc);
        return;
      }
      msgHandler = handlerMap[ev.type] /* check for exec per-row callback */;
      if(msgHandler && msgHandler.onrow){
        msgHandler.onrow(ev);
        return;
      }
      if(config.onunhandled) config.onunhandled(arguments[0]);
      else err("sqlite3Worker1Promiser() unhandled worker message:",ev);
      return;
    }
    delete handlerMap[ev.messageId];
    switch(ev.type){
        case 'error':







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  const genMsgId = config.generateMessageId || function(msg){
    return msg.type+'#'+(idTypeMap[msg.type] = (idTypeMap[msg.type]||0) + 1);
  };
  const toss = (...args)=>{throw new Error(args.join(' '))};
  if(!config.worker) config.worker = callee.defaultConfig.worker;
  if('function'===typeof config.worker) config.worker = config.worker();
  let dbId;

  config.worker.onmessage = function(ev){
    ev = ev.data;
    debug('worker1.onmessage',ev);
    let msgHandler = handlerMap[ev.messageId];
    if(!msgHandler){
      if(ev && 'sqlite3-api'===ev.type && 'worker1-ready'===ev.result) {
        /*fired one time when the Worker1 API initializes*/
        if(config.onready) config.onready();
        return;
      }
      msgHandler = handlerMap[ev.type] /* check for exec per-row callback */;
      if(msgHandler && msgHandler.onrow){
        msgHandler.onrow(ev);
        return;
      }        
      if(config.onunhandled) config.onunhandled(arguments[0]);
      else err("sqlite3Worker1Promiser() unhandled worker message:",ev);
      return;
    }
    delete handlerMap[ev.messageId];
    switch(ev.type){
        case 'error':
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          break;
        default:
          break;
    }
    try {msgHandler.resolve(ev)}
    catch(e){msgHandler.reject(e)}
  }/*worker.onmessage()*/;
  return promiserFunc = function(/*(msgType, msgArgs) || (msgEnvelope)*/){
    let msg;
    if(1===arguments.length){
      msg = arguments[0];
    }else if(2===arguments.length){
      msg = Object.create(null);
      msg.type = arguments[0];
      msg.args = arguments[1];
      msg.dbId = msg.args.dbId;

    }else{
      toss("Invalid arguments for sqlite3Worker1Promiser()-created factory.");
    }
    if(!msg.dbId && msg.type!=='open') msg.dbId = dbId;
    msg.messageId = genMsgId(msg);
    msg.departureTime = performance.now();
    const proxy = Object.create(null);
    proxy.message = msg;
    let rowCallbackId /* message handler ID for exec on-row callback proxy */;
    if('exec'===msg.type && msg.args){
      if('function'===typeof msg.args.callback){







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          break;
        default:
          break;
    }
    try {msgHandler.resolve(ev)}
    catch(e){msgHandler.reject(e)}
  }/*worker.onmessage()*/;
  return function(/*(msgType, msgArgs) || (msgEnvelope)*/){
    let msg;
    if(1===arguments.length){
      msg = arguments[0];
    }else if(2===arguments.length){
      msg = {
        type: arguments[0],
        args: arguments[1]

      };
    }else{
      toss("Invalid arugments for sqlite3Worker1Promiser()-created factory.");
    }
    if(!msg.dbId) msg.dbId = dbId;
    msg.messageId = genMsgId(msg);
    msg.departureTime = performance.now();
    const proxy = Object.create(null);
    proxy.message = msg;
    let rowCallbackId /* message handler ID for exec on-row callback proxy */;
    if('exec'===msg.type && msg.args){
      if('function'===typeof msg.args.callback){
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      debug("Posting",msg.type,"message to Worker dbId="+(dbId||'default')+':',msg);
      config.worker.postMessage(msg);
    });
    if(rowCallbackId) p = p.finally(()=>delete handlerMap[rowCallbackId]);
    return p;
  };
}/*sqlite3Worker1Promiser()*/;

globalThis.sqlite3Worker1Promiser.defaultConfig = {
  worker: function(){
//#if target=es6-module
    return new Worker(new URL("sqlite3-worker1-bundler-friendly.mjs", import.meta.url),{
      type: 'module'
    });
//#else
    let theJs = "sqlite3-worker1.js";
    if(this.currentScript){
      const src = this.currentScript.src.split('/');
      src.pop();
      theJs = src.join('/')+'/' + theJs;
      //sqlite3.config.warn("promiser currentScript, theJs =",this.currentScript,theJs);
    }else if(globalThis.location){
      //sqlite3.config.warn("promiser globalThis.location =",globalThis.location);
      const urlParams = new URL(globalThis.location.href).searchParams;
      if(urlParams.has('sqlite3.dir')){
        theJs = urlParams.get('sqlite3.dir') + '/' + theJs;
      }
    }
    return new Worker(theJs + globalThis.location.search);
//#endif
  }
//#ifnot target=es6-module
  .bind({
    currentScript: globalThis?.document?.currentScript
  })
//#endif
  ,
  onerror: (...args)=>console.error('worker1 promiser error',...args)
}/*defaultConfig*/;

/**
   sqlite3Worker1Promiser.v2(), added in 3.46, works identically to
   sqlite3Worker1Promiser() except that it returns a Promise instead
   of relying an an onready callback in the config object. The Promise
   resolves to the same factory function which
   sqlite3Worker1Promiser() returns.

   If config is-a function or is an object which contains an onready
   function, that function is replaced by a proxy which will resolve
   after calling the original function and will reject if that
   function throws.
*/
sqlite3Worker1Promiser.v2 = function(config){
  let oldFunc;
  if( 'function' == typeof config ){
    oldFunc = config;
    config = {};
  }else if('function'===typeof config?.onready){
    oldFunc = config.onready;
    delete config.onready;
  }
  const promiseProxy = Object.create(null);
  config = Object.assign((config || Object.create(null)),{
    onready: async function(func){
      try {
        if( oldFunc ) await oldFunc(func);
        promiseProxy.resolve(func);
      }
      catch(e){promiseProxy.reject(e)}
    }
  });
  const p = new Promise(function(resolve,reject){
    promiseProxy.resolve = resolve;
    promiseProxy.reject = reject;
  });
  try{
    this.original(config);
  }catch(e){
    promiseProxy.reject(e);
  }
  return p;
}.bind({
   /* We do this because clients are
      recommended to delete globalThis.sqlite3Worker1Promiser. */
  original: sqlite3Worker1Promiser
});

//#if target=es6-module
/**
  When built as a module, we export sqlite3Worker1Promiser.v2()
  instead of sqlite3Worker1Promise() because (A) its interface is more
  conventional for ESM usage and (B) the ESM option export option for
  this API did not exist until v2 was created, so there's no backwards
  incompatibility.
*/
export default sqlite3Worker1Promiser.v2;
//#endif /* target=es6-module */
//#else
/* Built with the omit-oo1 flag. */
//#endif ifnot omit-oo1







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      debug("Posting",msg.type,"message to Worker dbId="+(dbId||'default')+':',msg);
      config.worker.postMessage(msg);
    });
    if(rowCallbackId) p = p.finally(()=>delete handlerMap[rowCallbackId]);
    return p;
  };
}/*sqlite3Worker1Promiser()*/;

self.sqlite3Worker1Promiser.defaultConfig = {
  worker: function(){
//#if target=es6-bundler-friendly
    return new Worker("sqlite3-worker1.js");


//#else
    let theJs = "sqlite3-worker1.js";
    if(this.currentScript){
      const src = this.currentScript.src.split('/');
      src.pop();
      theJs = src.join('/')+'/' + theJs;
      //console.warn("promiser currentScript, theJs =",this.currentScript,theJs);
    }else{
      //console.warn("promiser self.location =",self.location);
      const urlParams = new URL(self.location.href).searchParams;
      if(urlParams.has('sqlite3.dir')){
        theJs = urlParams.get('sqlite3.dir') + '/' + theJs;
      }
    }
    return new Worker(theJs + self.location.search);
//#endif


  }.bind({
    currentScript: self?.document?.currentScript
  }),


  onerror: (...args)=>console.error('worker1 promiser error',...args)






















};







































Added ext/wasm/fiddle/fiddle.html.























































































































































































































































































































































































































































































































































































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<!doctype html>
<html lang="en-us">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>SQLite3 Fiddle</title>
    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
    <!-- to add a togglable terminal-style view, uncomment the following
         two lines and ensure that these files are on the web server. -->
    <!--script src="jqterm/jqterm-bundle.min.js"></script>
    <link rel="stylesheet" href="jqterm/jquery.terminal.min.css"/-->
    <link rel="stylesheet" href="emscripten.css"/>
    <style>
      /* The following styles are for app-level use. */
      :root {
          --sqlite-blue: #044a64;
          --textarea-color1: #044a64;
          --textarea-color2: white;
      }
      textarea {
          font-family: monospace;
          flex: 1 1 auto;
          background-color: var(--textarea-color1);
          color: var(--textarea-color2);
      }
      textarea#input {
          color: var(--textarea-color1);
          background-color: var(--textarea-color2);
      }
      header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          background-color: var(--sqlite-blue);
          color: white;
          font-size: 120%;
          font-weight: bold;
          border-radius: 0.25em;
          padding: 0.2em 0.5em;
      }
      header > .powered-by {
          font-size: 80%;
      }
      header a, header a:visited, header a:hover {
          color: inherit;
      }
      #main-wrapper {
          display: flex;
          flex-direction: column-reverse;
          flex: 1 1 auto;
          margin: 0.5em 0;
          overflow: hidden;
      }
      #main-wrapper.side-by-side {
          flex-direction: row;
      }
      #main-wrapper.side-by-side > fieldset {
          margin-left: 0.25em;
          margin-right: 0.25em;
      }
      #main-wrapper:not(.side-by-side) > fieldset {
          margin-bottom: 0.25em;
      }
      #main-wrapper.swapio {
          flex-direction: column;
      }
      #main-wrapper.side-by-side.swapio {
          flex-direction: row-reverse;
      }
      .zone-wrapper{
          display: flex;
          margin: 0;
          flex: 1 1 0%;
          border-radius: 0.5em;
          min-width: inherit/*important: resolves inability to scroll fieldset child element!*/;
          padding: 0.35em 0 0 0;
      }
      .zone-wrapper textarea {
          border-radius: 0.5em;
          flex: 1 1 auto;
          /*min/max width resolve an inexplicable margin on the RHS.  The -1em
            is for the padding, else we overlap the parent boundaries.*/
          /*min-width: calc(100% - 1em);
          max-width: calc(100% - 1em);
          padding: 0 0.5em;*/
      }

      .zone-wrapper.input { flex: 10 1 auto; }
      .zone-wrapper.output { flex: 20 1 auto; }
      .zone-wrapper > div {
          display:flex;
          flex: 1 1 0%;
      }
      .zone-wrapper.output {}
      .button-bar {
          display: flex;
          flex-wrap: wrap;
          align-items: center;
          align-content: space-between;
          justify-content: flex-start;
      }
      .button-bar > * {
          margin: 0.05em 0.5em 0.05em 0;
          flex: 0 1 auto;
          align-self: auto;
      }
      label[for] {
          cursor: pointer;
      }
      .error {
          color: red;
          background-color: yellow;
      }
      .hidden, .initially-hidden {
          position: absolute !important;
          opacity: 0 !important;
          pointer-events: none !important;
          display: none !important;
      }
      fieldset {
          border-radius: 0.5em;
          border: 1px inset;
          padding: 0.25em;
      }
      fieldset.options {
          font-size: 80%;
          margin-top: 0.5em;
      }
      fieldset:not(.options) > legend {
          font-size: 80%;
      }
      fieldset.options > div {
          display: flex;
          flex-wrap: wrap;
      }
      fieldset button {
          font-size: inherit;
      }
      fieldset.collapsible > legend > .fieldset-toggle::after {
          content: " [hide]";
          position: relative;
      }
      fieldset.collapsible.collapsed > legend > .fieldset-toggle::after {
          content: " [show]";
          position: relative;
      }
      span.labeled-input {
          padding: 0.25em;
          margin: 0.05em 0.25em;
          border-radius: 0.25em;
          white-space: nowrap;
          background: #0002;
          display: flex;
          align-items: center;
      }
      span.labeled-input > *:nth-child(2) {
          margin-left: 0.3em;
      }
      .center { text-align: center; }
      body.terminal-mode {
          max-height: calc(100% - 2em);
          display: flex;
          flex-direction: column;
          align-items: stretch;
      }
      #view-terminal {}
      .app-view {
          flex: 20 1 auto;
      }
      #view-split {
          display: flex;
          flex-direction: column-reverse;
      }
    </style>
  </head>
  <body>
    <header id='titlebar'>
      <span>SQLite3 Fiddle</span>
      <span class='powered-by'>Powered by
        <a href='https://sqlite.org'>SQLite3</a></span>
    </header>
    <!-- emscripten bits -->
    <figure id="module-spinner">
      <div class="spinner"></div>
      <div class='center'><strong>Initializing app...</strong></div>
      <div class='center'>
        On a slow internet connection this may take a moment.  If this
        message displays for "a long time", intialization may have
        failed and the JavaScript console may contain clues as to why.
      </div>
    </figure>
    <div class="emscripten" id="module-status">Downloading...</div>
    <div class="emscripten">
      <progress value="0" max="100" id="module-progress" hidden='1'></progress>  
    </div><!-- /emscripten bits -->

    <div id='view-terminal' class='app-view hidden initially-hidden'>
      This is a placeholder for a terminal-like view which is not in
      the default build.
    </div>

    <div id='view-split' class='app-view initially-hidden'>
      <fieldset class='options collapsible'>
        <legend><button class='fieldset-toggle'>Options</button></legend>
        <div class=''>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-sbs'
                   data-csstgt='#main-wrapper'
                   data-cssclass='side-by-side'
                   data-config='sideBySide'>
            <label for='opt-cb-sbs'>Side-by-side</label>
          </span>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-swapio'
                   data-csstgt='#main-wrapper'
                   data-cssclass='swapio'
                   data-config='swapInOut'>
            <label for='opt-cb-swapio'>Swap in/out</label>
          </span>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-autoscroll'
                   data-config='autoScrollOutput'>
            <label for='opt-cb-autoscroll'>Auto-scroll output</label>
          </span>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-autoclear'
                   data-config='autoClearOutput'>
            <label for='opt-cb-autoclear'>Auto-clear output</label>
          </span>
          <span class='labeled-input'>
            <input type='file' id='load-db' class='hidden'/>
            <button id='btn-load-db'>Load DB...</button>
          </span>
          <span class='labeled-input'>
            <button id='btn-export'>Download DB</button>
          </span>
          <span class='labeled-input'>
            <button id='btn-reset'>Reset DB</button>
          </span>
        </div>
      </fieldset><!-- .options -->
      <div id='main-wrapper' class=''>
        <fieldset class='zone-wrapper input'>
          <legend><div class='button-bar'>
            <button id='btn-shell-exec'>Run</button>
            <button id='btn-clear'>Clear Input</button>
            <!--button data-cmd='.help'>Help</button-->
            <select id='select-examples'></select>
          </div></legend>
          <div><textarea id="input"
                         placeholder="Shell input. Ctrl-enter/shift-enter runs it.">
-- ==================================================
-- Use ctrl-enter or shift-enter to execute sqlite3
-- shell commands and SQL.
-- If a subset of the text is currently selected,
-- only that part is executed.
-- ==================================================
.nullvalue NULL
.headers on
</textarea></div>
        </fieldset>
        <fieldset class='zone-wrapper output'>
          <legend><div class='button-bar'>
            <button id='btn-clear-output'>Clear Output</button>
            <button id='btn-interrupt' class='hidden' disabled>Interrupt</button>
            <!-- interruption cannot work in the current configuration
                 because we cannot send an interrupt message when work
                 is currently underway. At that point the Worker is
                 tied up and will not receive the message. -->
          </div></legend>
          <div><textarea id="output" readonly
                         placeholder="Shell output."></textarea></div>
        </fieldset>
      </div>
    </div> <!-- #view-split -->
    <!-- Maintenance notes:

        ... TODO... currently being refactored...

    -->
    <script src="fiddle.js"></script>
  </body>
</html>

Deleted ext/wasm/fiddle/index.html.

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<!doctype html>
<html lang="en-us">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>SQLite3 Fiddle</title>
    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
    <!-- to add a togglable terminal-style view, uncomment the following
         two lines and ensure that these files are on the web server. -->
    <!--script src="jqterm/jqterm-bundle.min.js"></script>
    <link rel="stylesheet" href="jqterm/jquery.terminal.min.css"/-->
    <link rel="stylesheet" href="emscripten.css"/>
    <style>
      /* The following styles are for app-level use. */
      :root {
          --sqlite-blue: #044a64;
          --textarea-color1: #044a64;
          --textarea-color2: white;
      }
      textarea {
          font-family: monospace;
          flex: 1 1 auto;
          background-color: var(--textarea-color1);
          color: var(--textarea-color2);
      }
      textarea#input {
          color: var(--textarea-color1);
          background-color: var(--textarea-color2);
      }
      header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          background-color: var(--sqlite-blue);
          color: white;
          font-size: 120%;
          font-weight: bold;
          border-radius: 0.25em;
          padding: 0.2em 0.5em;
      }
      header > .powered-by {
          font-size: 80%;
      }
      header a, header a:visited, header a:hover {
          color: inherit;
      }
      #main-wrapper {
          display: flex;
          flex-direction: column-reverse;
          flex: 1 1 auto;
          margin: 0.5em 0;
          overflow: hidden;
      }
      #main-wrapper.side-by-side {
          flex-direction: row;
      }
      #main-wrapper.side-by-side > fieldset {
          margin-left: 0.25em;
          margin-right: 0.25em;
      }
      #main-wrapper:not(.side-by-side) > fieldset {
          margin-bottom: 0.25em;
      }
      #main-wrapper.swapio {
          flex-direction: column;
      }
      #main-wrapper.side-by-side.swapio {
          flex-direction: row-reverse;
      }
      .zone-wrapper{
          display: flex;
          margin: 0;
          flex: 1 1 0%;
          border-radius: 0.5em;
          min-width: inherit/*important: resolves inability to scroll fieldset child element!*/;
          padding: 0.35em 0 0 0;
      }
      .zone-wrapper textarea {
          border-radius: 0.5em;
          flex: 1 1 auto;
          /*min/max width resolve an inexplicable margin on the RHS.  The -1em
            is for the padding, else we overlap the parent boundaries.*/
          /*min-width: calc(100% - 1em);
          max-width: calc(100% - 1em);
          padding: 0 0.5em;*/
      }

      .zone-wrapper.input { flex: 10 1 auto; }
      .zone-wrapper.output { flex: 20 1 auto; }
      .zone-wrapper > div {
          display:flex;
          flex: 1 1 0%;
      }
      .zone-wrapper.output {}
      .button-bar {
          display: flex;
          flex-wrap: wrap;
          align-items: center;
          align-content: space-between;
          justify-content: flex-start;
      }
      .button-bar > * {
          margin: 0.05em 0.5em 0.05em 0;
          flex: 0 1 auto;
          align-self: auto;
      }
      label[for] {
          cursor: pointer;
      }
      .error {
          color: red;
          background-color: yellow;
      }
      .hidden, .initially-hidden {
          position: absolute !important;
          opacity: 0 !important;
          pointer-events: none !important;
          display: none !important;
      }
      fieldset {
          border-radius: 0.5em;
          border: 1px inset;
          padding: 0.25em;
      }
      fieldset.options {
          font-size: 80%;
          margin-top: 0.5em;
      }
      fieldset:not(.options) > legend {
          font-size: 80%;
      }
      fieldset.options > div {
          display: flex;
          flex-wrap: wrap;
      }
      fieldset button {
          font-size: inherit;
      }
      fieldset.collapsible > legend > .fieldset-toggle::after {
          content: " [hide]";
          position: relative;
      }
      fieldset.collapsible.collapsed > legend > .fieldset-toggle::after {
          content: " [show]";
          position: relative;
      }
      span.labeled-input {
          padding: 0.25em;
          margin: 0.05em 0.25em;
          border-radius: 0.25em;
          white-space: nowrap;
          background: #0002;
          display: flex;
          align-items: center;
      }
      span.labeled-input > *:nth-child(2) {
          margin-left: 0.3em;
      }
      .center { text-align: center; }
      body.terminal-mode {
          max-height: calc(100% - 2em);
          display: flex;
          flex-direction: column;
          align-items: stretch;
      }
      #view-terminal {}
      .app-view {
          flex: 20 1 auto;
      }
      #view-split {
          display: flex;
          flex-direction: column-reverse;
      }
    </style>
  </head>
  <body>
    <header id='titlebar'>
      <span>SQLite3 Fiddle</span>
      <span class='powered-by'>Powered by
        <a href='https://sqlite.org'>SQLite3</a></span>
    </header>
    <!-- emscripten bits -->
    <figure id="module-spinner">
      <div class="spinner"></div>
      <div class='center'><strong>Initializing app...</strong></div>
      <div class='center'>
        On a slow internet connection this may take a moment.  If this
        message displays for "a long time", intialization may have
        failed and the JavaScript console may contain clues as to why.
      </div>
    </figure>
    <div class="emscripten" id="module-status">Downloading...</div>
    <div class="emscripten">
      <progress value="0" max="100" id="module-progress" hidden='1'></progress>  
    </div><!-- /emscripten bits -->

    <div id='view-terminal' class='app-view hidden initially-hidden'>
      This is a placeholder for a terminal-like view which is not in
      the default build.
    </div>

    <div id='view-split' class='app-view initially-hidden'>
      <fieldset class='options collapsible'>
        <legend><button class='fieldset-toggle'>Options</button></legend>
        <div class=''>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-sbs'
                   data-csstgt='#main-wrapper'
                   data-cssclass='side-by-side'
                   data-config='sideBySide'>
            <label for='opt-cb-sbs'>Side-by-side</label>
          </span>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-swapio'
                   data-csstgt='#main-wrapper'
                   data-cssclass='swapio'
                   data-config='swapInOut'>
            <label for='opt-cb-swapio'>Swap in/out</label>
          </span>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-autoscroll'
                   data-config='autoScrollOutput'>
            <label for='opt-cb-autoscroll'>Auto-scroll output</label>
          </span>
          <span class='labeled-input'>
            <input type='checkbox' id='opt-cb-autoclear'
                   data-config='autoClearOutput'>
            <label for='opt-cb-autoclear'>Auto-clear output</label>
          </span>
          <span class='labeled-input'>
            <input type='file' id='load-db' class='hidden'/>
            <button id='btn-load-db'>Load DB...</button>
          </span>
          <span class='labeled-input'>
            <button id='btn-export'>Download DB</button>
          </span>
          <span class='labeled-input'>
            <button id='btn-reset'>Reset DB</button>
          </span>
        </div>
      </fieldset><!-- .options -->
      <div id='main-wrapper' class=''>
        <fieldset class='zone-wrapper input'>
          <legend><div class='button-bar'>
            <button id='btn-shell-exec'>Run</button>
            <button id='btn-clear'>Clear Input</button>
            <!--button data-cmd='.help'>Help</button-->
            <select id='select-examples'></select>
          </div></legend>
          <div><textarea id="input"
                         placeholder="Shell input. Ctrl-enter/shift-enter runs it.">
-- ==================================================
-- Use ctrl-enter or shift-enter to execute sqlite3
-- shell commands and SQL.
-- If a subset of the text is currently selected,
-- only that part is executed.
-- ==================================================
.nullvalue NULL
.headers on
</textarea></div>
        </fieldset>
        <fieldset class='zone-wrapper output'>
          <legend><div class='button-bar'>
            <button id='btn-clear-output'>Clear Output</button>
            <button id='btn-interrupt' class='hidden' disabled>Interrupt</button>
            <!-- interruption cannot work in the current configuration
                 because we cannot send an interrupt message when work
                 is currently underway. At that point the Worker is
                 tied up and will not receive the message. -->
          </div></legend>
          <div><textarea id="output" readonly
                         placeholder="Shell output."></textarea></div>
        </fieldset>
      </div>
    </div> <!-- #view-split -->
    <script src="fiddle.js"></script>
  </body>
</html>
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Changes to main.mk.

339
340
341
342
343
344
345

346
347
348
349
350
351
352

# Extensions to be statically loaded.
#
TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/appendvfs.c \
  $(TOP)/ext/misc/basexx.c \

  $(TOP)/ext/misc/carray.c \
  $(TOP)/ext/misc/cksumvfs.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/csv.c \
  $(TOP)/ext/misc/decimal.c \
  $(TOP)/ext/misc/eval.c \
  $(TOP)/ext/misc/explain.c \







>







339
340
341
342
343
344
345
346
347
348
349
350
351
352
353

# Extensions to be statically loaded.
#
TESTSRC += \
  $(TOP)/ext/misc/amatch.c \
  $(TOP)/ext/misc/appendvfs.c \
  $(TOP)/ext/misc/basexx.c \
  $(TOP)/ext/misc/bgckpt.c \
  $(TOP)/ext/misc/carray.c \
  $(TOP)/ext/misc/cksumvfs.c \
  $(TOP)/ext/misc/closure.c \
  $(TOP)/ext/misc/csv.c \
  $(TOP)/ext/misc/decimal.c \
  $(TOP)/ext/misc/eval.c \
  $(TOP)/ext/misc/explain.c \

Changes to src/btree.c.

3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
    if( page1[18]>1 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
    if( page1[19]>1 ){
      goto page1_init_failed;
    }
#else
    if( page1[18]>2 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
    if( page1[19]>2 ){
      goto page1_init_failed;
    }

    /* If the read version is set to 2, this database should be accessed
    ** in WAL mode. If the log is not already open, open it now. Then
    ** return SQLITE_OK and return without populating BtShared.pPage1.
    ** The caller detects this and calls this function again. This is
    ** required as the version of page 1 currently in the page1 buffer
    ** may not be the latest version - there may be a newer one in the log
    ** file.
    */
    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
      int isOpen = 0;
      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
      if( rc!=SQLITE_OK ){
        goto page1_init_failed;
      }else{
        setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1);
        if( isOpen==0 ){
          releasePageOne(pPage1);
          return SQLITE_OK;







|


|











|

|







3304
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3310
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3332
3333
3334
3335
    if( page1[18]>1 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
    if( page1[19]>1 ){
      goto page1_init_failed;
    }
#else
    if( page1[18]>3 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
    if( page1[19]>3 ){
      goto page1_init_failed;
    }

    /* If the read version is set to 2, this database should be accessed
    ** in WAL mode. If the log is not already open, open it now. Then
    ** return SQLITE_OK and return without populating BtShared.pPage1.
    ** The caller detects this and calls this function again. This is
    ** required as the version of page 1 currently in the page1 buffer
    ** may not be the latest version - there may be a newer one in the log
    ** file.
    */
    if( page1[19]>=2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
      int isOpen = 0;
      rc = sqlite3PagerOpenWal(pBt->pPager, (page1[19]==3), &isOpen);
      if( rc!=SQLITE_OK ){
        goto page1_init_failed;
      }else{
        setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1);
        if( isOpen==0 ){
          releasePageOne(pPage1);
          return SQLITE_OK;
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11393
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11395
11396
11397
11398
** "write version" (single byte at byte offset 19) fields in the database
** header to iVersion.
*/
int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
  BtShared *pBt = pBtree->pBt;
  int rc;                         /* Return code */

  assert( iVersion==1 || iVersion==2 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->btsFlags &= ~BTS_NO_WAL;
  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;








|







11384
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11389
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11392
11393
11394
11395
11396
11397
11398
** "write version" (single byte at byte offset 19) fields in the database
** header to iVersion.
*/
int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
  BtShared *pBt = pBtree->pBt;
  int rc;                         /* Return code */

  assert( iVersion==1 || iVersion==2 || iVersion==3 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->btsFlags &= ~BTS_NO_WAL;
  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;

Changes to src/ctime.c.

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781

782
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785
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#endif
#ifdef SQLITE_USE_URI
  "USE_URI",
#endif
#ifdef SQLITE_VDBE_COVERAGE
  "VDBE_COVERAGE",
#endif

#ifdef SQLITE_WIN32_MALLOC
  "WIN32_MALLOC",
#endif
#ifdef SQLITE_ZERO_MALLOC
  "ZERO_MALLOC",
#endif








>







775
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785
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789
#endif
#ifdef SQLITE_USE_URI
  "USE_URI",
#endif
#ifdef SQLITE_VDBE_COVERAGE
  "VDBE_COVERAGE",
#endif
"WAL2",
#ifdef SQLITE_WIN32_MALLOC
  "WIN32_MALLOC",
#endif
#ifdef SQLITE_ZERO_MALLOC
  "ZERO_MALLOC",
#endif

Changes to src/pager.c.

785
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791
792
793
794
795
796
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798
799
800
801
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806
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810
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*/
#if SQLITE_MAX_MMAP_SIZE>0
# define USEFETCH(x) ((x)->bUseFetch)
#else
# define USEFETCH(x) 0
#endif

/*
** The argument to this macro is a file descriptor (type sqlite3_file*).
** Return 0 if it is not open, or non-zero (but not 1) if it is.
**
** This is so that expressions can be written as:
**
**   if( isOpen(pPager->jfd) ){ ...
**
** instead of
**
**   if( pPager->jfd->pMethods ){ ...
*/
#define isOpen(pFd) ((pFd)->pMethods!=0)

#ifdef SQLITE_DIRECT_OVERFLOW_READ
/*
** Return true if page pgno can be read directly from the database file
** by the b-tree layer. This is the case if:
**
**   * the database file is open,
**   * there are no dirty pages in the cache, and







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785
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790
791














792
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795
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798
*/
#if SQLITE_MAX_MMAP_SIZE>0
# define USEFETCH(x) ((x)->bUseFetch)
#else
# define USEFETCH(x) 0
#endif















#ifdef SQLITE_DIRECT_OVERFLOW_READ
/*
** Return true if page pgno can be read directly from the database file
** by the b-tree layer. This is the case if:
**
**   * the database file is open,
**   * there are no dirty pages in the cache, and
929
930
931
932
933
934
935

936
937
938
939
940
941
942
943
944
945
946
947
948
949

950
951
952
953
954
955
956
957
958
959
960
961

962
963
964
965
966
967
968
        ** a rollback transaction that switches from journal_mode=off
        ** to journal_mode=wal.
        */
        assert( p->eLock>=RESERVED_LOCK );
        assert( isOpen(p->jfd)
             || p->journalMode==PAGER_JOURNALMODE_OFF
             || p->journalMode==PAGER_JOURNALMODE_WAL

        );
      }
      assert( pPager->dbOrigSize==pPager->dbFileSize );
      assert( pPager->dbOrigSize==pPager->dbHintSize );
      break;

    case PAGER_WRITER_DBMOD:
      assert( p->eLock==EXCLUSIVE_LOCK );
      assert( pPager->errCode==SQLITE_OK );
      assert( !pagerUseWal(pPager) );
      assert( p->eLock>=EXCLUSIVE_LOCK );
      assert( isOpen(p->jfd)
           || p->journalMode==PAGER_JOURNALMODE_OFF
           || p->journalMode==PAGER_JOURNALMODE_WAL

           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
      );
      assert( pPager->dbOrigSize<=pPager->dbHintSize );
      break;

    case PAGER_WRITER_FINISHED:
      assert( p->eLock==EXCLUSIVE_LOCK );
      assert( pPager->errCode==SQLITE_OK );
      assert( !pagerUseWal(pPager) );
      assert( isOpen(p->jfd)
           || p->journalMode==PAGER_JOURNALMODE_OFF
           || p->journalMode==PAGER_JOURNALMODE_WAL

           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
      );
      break;

    case PAGER_ERROR:
      /* There must be at least one outstanding reference to the pager if
      ** in ERROR state. Otherwise the pager should have already dropped







>














>












>







915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
        ** a rollback transaction that switches from journal_mode=off
        ** to journal_mode=wal.
        */
        assert( p->eLock>=RESERVED_LOCK );
        assert( isOpen(p->jfd)
             || p->journalMode==PAGER_JOURNALMODE_OFF
             || p->journalMode==PAGER_JOURNALMODE_WAL
             || p->journalMode==PAGER_JOURNALMODE_WAL2
        );
      }
      assert( pPager->dbOrigSize==pPager->dbFileSize );
      assert( pPager->dbOrigSize==pPager->dbHintSize );
      break;

    case PAGER_WRITER_DBMOD:
      assert( p->eLock==EXCLUSIVE_LOCK );
      assert( pPager->errCode==SQLITE_OK );
      assert( !pagerUseWal(pPager) );
      assert( p->eLock>=EXCLUSIVE_LOCK );
      assert( isOpen(p->jfd)
           || p->journalMode==PAGER_JOURNALMODE_OFF
           || p->journalMode==PAGER_JOURNALMODE_WAL
           || p->journalMode==PAGER_JOURNALMODE_WAL2
           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
      );
      assert( pPager->dbOrigSize<=pPager->dbHintSize );
      break;

    case PAGER_WRITER_FINISHED:
      assert( p->eLock==EXCLUSIVE_LOCK );
      assert( pPager->errCode==SQLITE_OK );
      assert( !pagerUseWal(pPager) );
      assert( isOpen(p->jfd)
           || p->journalMode==PAGER_JOURNALMODE_OFF
           || p->journalMode==PAGER_JOURNALMODE_WAL
           || p->journalMode==PAGER_JOURNALMODE_WAL2
           || (sqlite3OsDeviceCharacteristics(p->fd)&SQLITE_IOCAP_BATCH_ATOMIC)
      );
      break;

    case PAGER_ERROR:
      /* There must be at least one outstanding reference to the pager if
      ** in ERROR state. Otherwise the pager should have already dropped
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097

2098
2099
2100
2101
2102
2103
2104
          ** https://bugzilla.mozilla.org/show_bug.cgi?id=1072773
          */
          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
        }
      }
      pPager->journalOff = 0;
    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
      || (pPager->exclusiveMode && pPager->journalMode!=PAGER_JOURNALMODE_WAL)
    ){
      rc = zeroJournalHdr(pPager, hasSuper||pPager->tempFile);
      pPager->journalOff = 0;
    }else{
      /* This branch may be executed with Pager.journalMode==MEMORY if
      ** a hot-journal was just rolled back. In this case the journal
      ** file should be closed and deleted. If this connection writes to
      ** the database file, it will do so using an in-memory journal.
      */
      int bDelete = !pPager->tempFile;
      assert( sqlite3JournalIsInMemory(pPager->jfd)==0 );
      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE
           || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
           || pPager->journalMode==PAGER_JOURNALMODE_WAL

      );
      sqlite3OsClose(pPager->jfd);
      if( bDelete ){
        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, pPager->extraSync);
      }
    }
  }







|














>







2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
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2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
          ** https://bugzilla.mozilla.org/show_bug.cgi?id=1072773
          */
          rc = sqlite3OsSync(pPager->jfd, pPager->syncFlags);
        }
      }
      pPager->journalOff = 0;
    }else if( pPager->journalMode==PAGER_JOURNALMODE_PERSIST
      || (pPager->exclusiveMode && pPager->journalMode<PAGER_JOURNALMODE_WAL)
    ){
      rc = zeroJournalHdr(pPager, hasSuper||pPager->tempFile);
      pPager->journalOff = 0;
    }else{
      /* This branch may be executed with Pager.journalMode==MEMORY if
      ** a hot-journal was just rolled back. In this case the journal
      ** file should be closed and deleted. If this connection writes to
      ** the database file, it will do so using an in-memory journal.
      */
      int bDelete = !pPager->tempFile;
      assert( sqlite3JournalIsInMemory(pPager->jfd)==0 );
      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE
           || pPager->journalMode==PAGER_JOURNALMODE_MEMORY
           || pPager->journalMode==PAGER_JOURNALMODE_WAL
           || pPager->journalMode==PAGER_JOURNALMODE_WAL2
      );
      sqlite3OsClose(pPager->jfd);
      if( bDelete ){
        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, pPager->extraSync);
      }
    }
  }
3246
3247
3248
3249
3250
3251
3252




3253
3254
3255
3256
3257
3258
3259
  */
  sqlite3WalEndReadTransaction(pPager->pWal);

  rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
  if( rc!=SQLITE_OK || changed ){
    pager_reset(pPager);
    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);




  }

  return rc;
}
#endif

/*







>
>
>
>







3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
  */
  sqlite3WalEndReadTransaction(pPager->pWal);

  rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
  if( rc!=SQLITE_OK || changed ){
    pager_reset(pPager);
    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
    assert( pPager->journalMode==PAGER_JOURNALMODE_WAL
         || pPager->journalMode==PAGER_JOURNALMODE_WAL2
    );
    pPager->journalMode = sqlite3WalJournalMode(pPager->pWal);
  }

  return rc;
}
#endif

/*
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357

        rc = pagerPagecount(pPager, &nPage);
        if( rc ) return rc;
        if( nPage==0 ){
          rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
        }else{
          testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
          rc = sqlite3PagerOpenWal(pPager, 0);
        }
      }else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
        pPager->journalMode = PAGER_JOURNALMODE_DELETE;
      }
    }
  }
  return rc;
}
#endif







|

|







3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351

        rc = pagerPagecount(pPager, &nPage);
        if( rc ) return rc;
        if( nPage==0 ){
          rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
        }else{
          testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
          rc = sqlite3PagerOpenWal(pPager, 0, 0);
        }
      }else if( pPager->journalMode>=PAGER_JOURNALMODE_WAL ){
        pPager->journalMode = PAGER_JOURNALMODE_DELETE;
      }
    }
  }
  return rc;
}
#endif
4847
4848
4849
4850
4851
4852
4853

4854
4855
4856
4857
4858
4859
4860
    SQLITE_PTRSIZE +                     /* Space to hold a pointer */
    4 +                                  /* Database prefix */
    nPathname + 1 +                      /* database filename */
    nUriByte +                           /* query parameters */
    nPathname + 8 + 1 +                  /* Journal filename */
#ifndef SQLITE_OMIT_WAL
    nPathname + 4 + 1 +                  /* WAL filename */

#endif
    3                                    /* Terminator */
  );
  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
  if( !pPtr ){
    sqlite3DbFree(0, zPathname);
    return SQLITE_NOMEM_BKPT;







>







4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
    SQLITE_PTRSIZE +                     /* Space to hold a pointer */
    4 +                                  /* Database prefix */
    nPathname + 1 +                      /* database filename */
    nUriByte +                           /* query parameters */
    nPathname + 8 + 1 +                  /* Journal filename */
#ifndef SQLITE_OMIT_WAL
    nPathname + 4 + 1 +                  /* WAL filename */
    nPathname + 5 + 1 +                  /* Second WAL filename */
#endif
    3                                    /* Terminator */
  );
  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
  if( !pPtr ){
    sqlite3DbFree(0, zPathname);
    return SQLITE_NOMEM_BKPT;
4899
4900
4901
4902
4903
4904
4905


4906
4907
4908
4909
4910
4911
4912
    pPager->zWal = (char*)pPtr;
    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
    memcpy(pPtr, "-wal", 4);              pPtr += 4 + 1;
#ifdef SQLITE_ENABLE_8_3_NAMES
    sqlite3FileSuffix3(zFilename, pPager->zWal);
    pPtr = (u8*)(pPager->zWal + sqlite3Strlen30(pPager->zWal)+1);
#endif


  }else{
    pPager->zWal = 0;
  }
#endif
  (void)pPtr;  /* Suppress warning about unused pPtr value */

  if( nPathname ) sqlite3DbFree(0, zPathname);







>
>







4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
    pPager->zWal = (char*)pPtr;
    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
    memcpy(pPtr, "-wal", 4);              pPtr += 4 + 1;
#ifdef SQLITE_ENABLE_8_3_NAMES
    sqlite3FileSuffix3(zFilename, pPager->zWal);
    pPtr = (u8*)(pPager->zWal + sqlite3Strlen30(pPager->zWal)+1);
#endif
    memcpy(pPtr, zPathname, nPathname);   pPtr += nPathname;
    memcpy(pPtr, "-wal2", 5);             pPtr += 5 + 1;
  }else{
    pPager->zWal = 0;
  }
#endif
  (void)pPtr;  /* Suppress warning about unused pPtr value */

  if( nPathname ) sqlite3DbFree(0, zPathname);
7335
7336
7337
7338
7339
7340
7341

7342
7343
7344
7345
7346
7347
7348
7349

  /* The eMode parameter is always valid */
  assert(      eMode==PAGER_JOURNALMODE_DELETE    /* 0 */
            || eMode==PAGER_JOURNALMODE_PERSIST   /* 1 */
            || eMode==PAGER_JOURNALMODE_OFF       /* 2 */
            || eMode==PAGER_JOURNALMODE_TRUNCATE  /* 3 */
            || eMode==PAGER_JOURNALMODE_MEMORY    /* 4 */

            || eMode==PAGER_JOURNALMODE_WAL       /* 5 */ );

  /* This routine is only called from the OP_JournalMode opcode, and
  ** the logic there will never allow a temporary file to be changed
  ** to WAL mode.
  */
  assert( pPager->tempFile==0 || eMode!=PAGER_JOURNALMODE_WAL );








>
|







7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347

  /* The eMode parameter is always valid */
  assert(      eMode==PAGER_JOURNALMODE_DELETE    /* 0 */
            || eMode==PAGER_JOURNALMODE_PERSIST   /* 1 */
            || eMode==PAGER_JOURNALMODE_OFF       /* 2 */
            || eMode==PAGER_JOURNALMODE_TRUNCATE  /* 3 */
            || eMode==PAGER_JOURNALMODE_MEMORY    /* 4 */
            || eMode==PAGER_JOURNALMODE_WAL       /* 5 */
            || eMode==PAGER_JOURNALMODE_WAL2      /* 6 */ );

  /* This routine is only called from the OP_JournalMode opcode, and
  ** the logic there will never allow a temporary file to be changed
  ** to WAL mode.
  */
  assert( pPager->tempFile==0 || eMode!=PAGER_JOURNALMODE_WAL );

7369
7370
7371
7372
7373
7374
7375

7376
7377
7378


7379
7380
7381
7382
7383
7384
7385
    */
    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
    assert( (PAGER_JOURNALMODE_PERSIST & 5)==1 );
    assert( (PAGER_JOURNALMODE_DELETE & 5)==0 );
    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );
    assert( (PAGER_JOURNALMODE_OFF & 5)==0 );
    assert( (PAGER_JOURNALMODE_WAL & 5)==5 );


    assert( isOpen(pPager->fd) || pPager->exclusiveMode );
    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 ){


      /* In this case we would like to delete the journal file. If it is
      ** not possible, then that is not a problem. Deleting the journal file
      ** here is an optimization only.
      **
      ** Before deleting the journal file, obtain a RESERVED lock on the
      ** database file. This ensures that the journal file is not deleted
      ** while it is in use by some other client.







>


|
>
>







7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
    */
    assert( (PAGER_JOURNALMODE_TRUNCATE & 5)==1 );
    assert( (PAGER_JOURNALMODE_PERSIST & 5)==1 );
    assert( (PAGER_JOURNALMODE_DELETE & 5)==0 );
    assert( (PAGER_JOURNALMODE_MEMORY & 5)==4 );
    assert( (PAGER_JOURNALMODE_OFF & 5)==0 );
    assert( (PAGER_JOURNALMODE_WAL & 5)==5 );
    assert( (PAGER_JOURNALMODE_WAL2 & 5)==4 );

    assert( isOpen(pPager->fd) || pPager->exclusiveMode );
    if( !pPager->exclusiveMode && (eOld & 5)==1 && (eMode & 1)==0 
     && eMode!=PAGER_JOURNALMODE_WAL2       /* TODO: fix this if possible */
    ){
      /* In this case we would like to delete the journal file. If it is
      ** not possible, then that is not a problem. Deleting the journal file
      ** here is an optimization only.
      **
      ** Before deleting the journal file, obtain a RESERVED lock on the
      ** database file. This ensures that the journal file is not deleted
      ** while it is in use by some other client.
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581

/*
** Call sqlite3WalOpen() to open the WAL handle. If the pager is in
** exclusive-locking mode when this function is called, take an EXCLUSIVE
** lock on the database file and use heap-memory to store the wal-index
** in. Otherwise, use the normal shared-memory.
*/
static int pagerOpenWal(Pager *pPager){
  int rc = SQLITE_OK;

  assert( pPager->pWal==0 && pPager->tempFile==0 );
  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );

  /* If the pager is already in exclusive-mode, the WAL module will use
  ** heap-memory for the wal-index instead of the VFS shared-memory
  ** implementation. Take the exclusive lock now, before opening the WAL
  ** file, to make sure this is safe.
  */
  if( pPager->exclusiveMode ){
    rc = pagerExclusiveLock(pPager);
  }

  /* Open the connection to the log file. If this operation fails,
  ** (e.g. due to malloc() failure), return an error code.
  */
  if( rc==SQLITE_OK ){
    rc = sqlite3WalOpen(pPager->pVfs,
        pPager->fd, pPager->zWal, pPager->exclusiveMode,
        pPager->journalSizeLimit, &pPager->pWal
    );
  }
  pagerFixMaplimit(pPager);

  return rc;
}








|




















|







7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582

/*
** Call sqlite3WalOpen() to open the WAL handle. If the pager is in
** exclusive-locking mode when this function is called, take an EXCLUSIVE
** lock on the database file and use heap-memory to store the wal-index
** in. Otherwise, use the normal shared-memory.
*/
static int pagerOpenWal(Pager *pPager, int bWal2){
  int rc = SQLITE_OK;

  assert( pPager->pWal==0 && pPager->tempFile==0 );
  assert( pPager->eLock==SHARED_LOCK || pPager->eLock==EXCLUSIVE_LOCK );

  /* If the pager is already in exclusive-mode, the WAL module will use
  ** heap-memory for the wal-index instead of the VFS shared-memory
  ** implementation. Take the exclusive lock now, before opening the WAL
  ** file, to make sure this is safe.
  */
  if( pPager->exclusiveMode ){
    rc = pagerExclusiveLock(pPager);
  }

  /* Open the connection to the log file. If this operation fails,
  ** (e.g. due to malloc() failure), return an error code.
  */
  if( rc==SQLITE_OK ){
    rc = sqlite3WalOpen(pPager->pVfs,
        pPager->fd, pPager->zWal, pPager->exclusiveMode,
        pPager->journalSizeLimit, bWal2, &pPager->pWal
    );
  }
  pagerFixMaplimit(pPager);

  return rc;
}

7593
7594
7595
7596
7597
7598
7599

7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
**
** If the pager is open on a temp-file (or in-memory database), or if
** the WAL file is already open, set *pbOpen to 1 and return SQLITE_OK
** without doing anything.
*/
int sqlite3PagerOpenWal(
  Pager *pPager,                  /* Pager object */

  int *pbOpen                     /* OUT: Set to true if call is a no-op */
){
  int rc = SQLITE_OK;             /* Return code */

  assert( assert_pager_state(pPager) );
  assert( pPager->eState==PAGER_OPEN   || pbOpen );
  assert( pPager->eState==PAGER_READER || !pbOpen );
  assert( pbOpen==0 || *pbOpen==0 );
  assert( pbOpen!=0 || (!pPager->tempFile && !pPager->pWal) );

  if( !pPager->tempFile && !pPager->pWal ){
    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;

    /* Close any rollback journal previously open */
    sqlite3OsClose(pPager->jfd);

    rc = pagerOpenWal(pPager);
    if( rc==SQLITE_OK ){
      pPager->journalMode = PAGER_JOURNALMODE_WAL;
      pPager->eState = PAGER_OPEN;
    }
  }else{
    *pbOpen = 1;
  }

  return rc;







>
















|

|







7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
**
** If the pager is open on a temp-file (or in-memory database), or if
** the WAL file is already open, set *pbOpen to 1 and return SQLITE_OK
** without doing anything.
*/
int sqlite3PagerOpenWal(
  Pager *pPager,                  /* Pager object */
  int bWal2,                      /* Open in wal2 mode if not already open */
  int *pbOpen                     /* OUT: Set to true if call is a no-op */
){
  int rc = SQLITE_OK;             /* Return code */

  assert( assert_pager_state(pPager) );
  assert( pPager->eState==PAGER_OPEN   || pbOpen );
  assert( pPager->eState==PAGER_READER || !pbOpen );
  assert( pbOpen==0 || *pbOpen==0 );
  assert( pbOpen!=0 || (!pPager->tempFile && !pPager->pWal) );

  if( !pPager->tempFile && !pPager->pWal ){
    if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;

    /* Close any rollback journal previously open */
    sqlite3OsClose(pPager->jfd);

    rc = pagerOpenWal(pPager, bWal2);
    if( rc==SQLITE_OK ){
      pPager->journalMode = bWal2?PAGER_JOURNALMODE_WAL2:PAGER_JOURNALMODE_WAL;
      pPager->eState = PAGER_OPEN;
    }
  }else{
    *pbOpen = 1;
  }

  return rc;
7633
7634
7635
7636
7637
7638
7639
7640


7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
** EXCLUSIVE lock on the database file. If this cannot be obtained, an
** error (SQLITE_BUSY) is returned and the log connection is not closed.
** If successful, the EXCLUSIVE lock is not released before returning.
*/
int sqlite3PagerCloseWal(Pager *pPager, sqlite3 *db){
  int rc = SQLITE_OK;

  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL );



  /* If the log file is not already open, but does exist in the file-system,
  ** it may need to be checkpointed before the connection can switch to
  ** rollback mode. Open it now so this can happen.
  */
  if( !pPager->pWal ){
    int logexists = 0;
    rc = pagerLockDb(pPager, SHARED_LOCK);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsAccess(
          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
      );
    }
    if( rc==SQLITE_OK && logexists ){
      rc = pagerOpenWal(pPager);
    }
  }
   
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pWal ){







|
>
>














|







7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
** EXCLUSIVE lock on the database file. If this cannot be obtained, an
** error (SQLITE_BUSY) is returned and the log connection is not closed.
** If successful, the EXCLUSIVE lock is not released before returning.
*/
int sqlite3PagerCloseWal(Pager *pPager, sqlite3 *db){
  int rc = SQLITE_OK;

  assert( pPager->journalMode==PAGER_JOURNALMODE_WAL 
       || pPager->journalMode==PAGER_JOURNALMODE_WAL2
  );

  /* If the log file is not already open, but does exist in the file-system,
  ** it may need to be checkpointed before the connection can switch to
  ** rollback mode. Open it now so this can happen.
  */
  if( !pPager->pWal ){
    int logexists = 0;
    rc = pagerLockDb(pPager, SHARED_LOCK);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsAccess(
          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
      );
    }
    if( rc==SQLITE_OK && logexists ){
      rc = pagerOpenWal(pPager, 0);
    }
  }
   
  /* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
  ** the database file, the log and log-summary files will be deleted.
  */
  if( rc==SQLITE_OK && pPager->pWal ){

Changes to src/pager.h.

78
79
80
81
82
83
84

















85
86
87
88
89
90
91
#define PAGER_JOURNALMODE_QUERY     (-1)  /* Query the value of journalmode */
#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
#define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
#define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */


















/*
** Flags that make up the mask passed to sqlite3PagerGet().
*/
#define PAGER_GET_NOCONTENT     0x01  /* Do not load data from disk */
#define PAGER_GET_READONLY      0x02  /* Read-only page is acceptable */








>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
#define PAGER_JOURNALMODE_QUERY     (-1)  /* Query the value of journalmode */
#define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
#define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
#define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
#define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
#define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
#define PAGER_JOURNALMODE_WAL2        6   /* Use write-ahead logging mode 2 */

#define isWalMode(x) ((x)==PAGER_JOURNALMODE_WAL || (x)==PAGER_JOURNALMODE_WAL2)

/*
** The argument to this macro is a file descriptor (type sqlite3_file*).
** Return 0 if it is not open, or non-zero (but not 1) if it is.
**
** This is so that expressions can be written as:
**
**   if( isOpen(pPager->jfd) ){ ...
**
** instead of
**
**   if( pPager->jfd->pMethods ){ ...
*/
#define isOpen(pFd) ((pFd)->pMethods!=0)

/*
** Flags that make up the mask passed to sqlite3PagerGet().
*/
#define PAGER_GET_NOCONTENT     0x01  /* Do not load data from disk */
#define PAGER_GET_READONLY      0x02  /* Read-only page is acceptable */

171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
int sqlite3PagerSharedLock(Pager *pPager);

#ifndef SQLITE_OMIT_WAL
  int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*);
  int sqlite3PagerWalSupported(Pager *pPager);
  int sqlite3PagerWalCallback(Pager *pPager);
  int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
  int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
# ifdef SQLITE_ENABLE_SNAPSHOT
  int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot);
  int sqlite3PagerSnapshotOpen(Pager*, sqlite3_snapshot *pSnapshot);
  int sqlite3PagerSnapshotRecover(Pager *pPager);
  int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot);
  void sqlite3PagerSnapshotUnlock(Pager *pPager);







|







188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
int sqlite3PagerSavepoint(Pager *pPager, int op, int iSavepoint);
int sqlite3PagerSharedLock(Pager *pPager);

#ifndef SQLITE_OMIT_WAL
  int sqlite3PagerCheckpoint(Pager *pPager, sqlite3*, int, int*, int*);
  int sqlite3PagerWalSupported(Pager *pPager);
  int sqlite3PagerWalCallback(Pager *pPager);
  int sqlite3PagerOpenWal(Pager *pPager, int, int *pisOpen);
  int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
# ifdef SQLITE_ENABLE_SNAPSHOT
  int sqlite3PagerSnapshotGet(Pager*, sqlite3_snapshot **ppSnapshot);
  int sqlite3PagerSnapshotOpen(Pager*, sqlite3_snapshot *pSnapshot);
  int sqlite3PagerSnapshotRecover(Pager *pPager);
  int sqlite3PagerSnapshotCheck(Pager *pPager, sqlite3_snapshot *pSnapshot);
  void sqlite3PagerSnapshotUnlock(Pager *pPager);

Changes to src/pragma.c.

286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301

302
303
304
305
306
307
308
** defined in pager.h. This function returns the associated lowercase
** journal-mode name.
*/
const char *sqlite3JournalModename(int eMode){
  static char * const azModeName[] = {
    "delete", "persist", "off", "truncate", "memory"
#ifndef SQLITE_OMIT_WAL
     , "wal"
#endif
  };
  assert( PAGER_JOURNALMODE_DELETE==0 );
  assert( PAGER_JOURNALMODE_PERSIST==1 );
  assert( PAGER_JOURNALMODE_OFF==2 );
  assert( PAGER_JOURNALMODE_TRUNCATE==3 );
  assert( PAGER_JOURNALMODE_MEMORY==4 );
  assert( PAGER_JOURNALMODE_WAL==5 );

  assert( eMode>=0 && eMode<=ArraySize(azModeName) );

  if( eMode==ArraySize(azModeName) ) return 0;
  return azModeName[eMode];
}

/*







|








>







286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
** defined in pager.h. This function returns the associated lowercase
** journal-mode name.
*/
const char *sqlite3JournalModename(int eMode){
  static char * const azModeName[] = {
    "delete", "persist", "off", "truncate", "memory"
#ifndef SQLITE_OMIT_WAL
     , "wal", "wal2"
#endif
  };
  assert( PAGER_JOURNALMODE_DELETE==0 );
  assert( PAGER_JOURNALMODE_PERSIST==1 );
  assert( PAGER_JOURNALMODE_OFF==2 );
  assert( PAGER_JOURNALMODE_TRUNCATE==3 );
  assert( PAGER_JOURNALMODE_MEMORY==4 );
  assert( PAGER_JOURNALMODE_WAL==5 );
  assert( PAGER_JOURNALMODE_WAL2==6 );
  assert( eMode>=0 && eMode<=ArraySize(azModeName) );

  if( eMode==ArraySize(azModeName) ) return 0;
  return azModeName[eMode];
}

/*

Changes to src/test_hexio.c.

186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209

210
211







212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227



228

229
230
231
232
233
234
235
  sqlite3_free(aOut);
  fclose(out);
  Tcl_SetObjResult(interp, Tcl_NewIntObj(written));
  return TCL_OK;
}

/*
** USAGE:   hexio_get_int   HEXDATA
**
** Interpret the HEXDATA argument as a big-endian integer.  Return
** the value of that integer.  HEXDATA can contain between 2 and 8
** hexadecimal digits.
*/
static int SQLITE_TCLAPI hexio_get_int(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int val;
  int nIn, nOut;
  const unsigned char *zIn;
  unsigned char *aOut;
  unsigned char aNum[4];


  if( objc!=2 ){







    Tcl_WrongNumArgs(interp, 1, objv, "HEXDATA");
    return TCL_ERROR;
  }
  zIn = (const unsigned char *)Tcl_GetStringFromObj(objv[1], &nIn);
  aOut = sqlite3_malloc( 1 + nIn/2 );
  if( aOut==0 ){
    return TCL_ERROR;
  }
  nOut = sqlite3TestHexToBin(zIn, nIn, aOut);
  if( nOut>=4 ){
    memcpy(aNum, aOut, 4);
  }else{
    memset(aNum, 0, sizeof(aNum));
    memcpy(&aNum[4-nOut], aOut, nOut);
  }
  sqlite3_free(aOut);



  val = (aNum[0]<<24) | (aNum[1]<<16) | (aNum[2]<<8) | aNum[3];

  Tcl_SetObjResult(interp, Tcl_NewIntObj(val));
  return TCL_OK;
}


/*
** USAGE:   hexio_render_int16   INTEGER







|
















>

|
>
>
>
>
>
>
>
|


|












>
>
>
|
>







186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
  sqlite3_free(aOut);
  fclose(out);
  Tcl_SetObjResult(interp, Tcl_NewIntObj(written));
  return TCL_OK;
}

/*
** USAGE:   hexio_get_int [-littleendian] HEXDATA
**
** Interpret the HEXDATA argument as a big-endian integer.  Return
** the value of that integer.  HEXDATA can contain between 2 and 8
** hexadecimal digits.
*/
static int SQLITE_TCLAPI hexio_get_int(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int val;
  int nIn, nOut;
  const unsigned char *zIn;
  unsigned char *aOut;
  unsigned char aNum[4];
  int bLittle = 0;

  if( objc==3 ){
    int n;
    char *z = Tcl_GetStringFromObj(objv[1], &n);
    if( n>=2 && n<=13 && memcmp(z, "-littleendian", n)==0 ){
      bLittle = 1;
    }
  }
  if( (objc-bLittle)!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "[-littleendian] HEXDATA");
    return TCL_ERROR;
  }
  zIn = (const unsigned char *)Tcl_GetStringFromObj(objv[1+bLittle], &nIn);
  aOut = sqlite3_malloc( 1 + nIn/2 );
  if( aOut==0 ){
    return TCL_ERROR;
  }
  nOut = sqlite3TestHexToBin(zIn, nIn, aOut);
  if( nOut>=4 ){
    memcpy(aNum, aOut, 4);
  }else{
    memset(aNum, 0, sizeof(aNum));
    memcpy(&aNum[4-nOut], aOut, nOut);
  }
  sqlite3_free(aOut);
  if( bLittle ){
    val = (aNum[3]<<24) | (aNum[2]<<16) | (aNum[1]<<8) | aNum[0];
  }else{
    val = (aNum[0]<<24) | (aNum[1]<<16) | (aNum[2]<<8) | aNum[3];
  }
  Tcl_SetObjResult(interp, Tcl_NewIntObj(val));
  return TCL_OK;
}


/*
** USAGE:   hexio_render_int16   INTEGER

Changes to src/test_tclsh.c.

94
95
96
97
98
99
100

101
102
103
104
105
106
107
#if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK)
  extern int TestSession_Init(Tcl_Interp*);
#endif
  extern int Md5_Init(Tcl_Interp*);
  extern int Fts5tcl_Init(Tcl_Interp *);
  extern int SqliteRbu_Init(Tcl_Interp*);
  extern int Sqlitetesttcl_Init(Tcl_Interp*);

#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  extern int Sqlitetestfts3_Init(Tcl_Interp *interp);
#endif
#ifdef SQLITE_ENABLE_ZIPVFS
  extern int Zipvfs_Init(Tcl_Interp*);
#endif
  extern int TestExpert_Init(Tcl_Interp*);







>







94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
#if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK)
  extern int TestSession_Init(Tcl_Interp*);
#endif
  extern int Md5_Init(Tcl_Interp*);
  extern int Fts5tcl_Init(Tcl_Interp *);
  extern int SqliteRbu_Init(Tcl_Interp*);
  extern int Sqlitetesttcl_Init(Tcl_Interp*);
  extern int Bgckpt_Init(Tcl_Interp*);
#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  extern int Sqlitetestfts3_Init(Tcl_Interp *interp);
#endif
#ifdef SQLITE_ENABLE_ZIPVFS
  extern int Zipvfs_Init(Tcl_Interp*);
#endif
  extern int TestExpert_Init(Tcl_Interp*);
164
165
166
167
168
169
170


171
172
173
174
175
176
177
  SqlitetestSyscall_Init(interp);
#if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK)
  TestSession_Init(interp);
#endif
  Fts5tcl_Init(interp);
  SqliteRbu_Init(interp);
  Sqlitetesttcl_Init(interp);



#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  Sqlitetestfts3_Init(interp);
#endif
  TestExpert_Init(interp);
  Sqlitetest_window_Init(interp);
  Sqlitetestvdbecov_Init(interp);







>
>







165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
  SqlitetestSyscall_Init(interp);
#if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK)
  TestSession_Init(interp);
#endif
  Fts5tcl_Init(interp);
  SqliteRbu_Init(interp);
  Sqlitetesttcl_Init(interp);
  Bgckpt_Init(interp);


#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)
  Sqlitetestfts3_Init(interp);
#endif
  TestExpert_Init(interp);
  Sqlitetest_window_Init(interp);
  Sqlitetestvdbecov_Init(interp);

Changes to src/vdbe.c.

7872
7873
7874
7875
7876
7877
7878

7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905





7906




7907
7908
7909
7910
7911
7912
7913
7914
7915
7916

7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936

7937


7938
7939
7940
7941
7942
7943
7944
7945
  eNew = pOp->p3;
  assert( eNew==PAGER_JOURNALMODE_DELETE
       || eNew==PAGER_JOURNALMODE_TRUNCATE
       || eNew==PAGER_JOURNALMODE_PERSIST
       || eNew==PAGER_JOURNALMODE_OFF
       || eNew==PAGER_JOURNALMODE_MEMORY
       || eNew==PAGER_JOURNALMODE_WAL

       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( p->readOnly==0 );

  pBt = db->aDb[pOp->p1].pBt;
  pPager = sqlite3BtreePager(pBt);
  eOld = sqlite3PagerGetJournalMode(pPager);
  if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
  assert( sqlite3BtreeHoldsMutex(pBt) );
  if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;

#ifndef SQLITE_OMIT_WAL
  zFilename = sqlite3PagerFilename(pPager, 1);

  /* Do not allow a transition to journal_mode=WAL for a database
  ** in temporary storage or if the VFS does not support shared memory
  */
  if( eNew==PAGER_JOURNALMODE_WAL
   && (sqlite3Strlen30(zFilename)==0           /* Temp file */
       || !sqlite3PagerWalSupported(pPager))   /* No shared-memory support */
  ){
    eNew = eOld;
  }

  if( (eNew!=eOld)
   && (eOld==PAGER_JOURNALMODE_WAL || eNew==PAGER_JOURNALMODE_WAL)





  ){




    if( !db->autoCommit || db->nVdbeRead>1 ){
      rc = SQLITE_ERROR;
      sqlite3VdbeError(p,
          "cannot change %s wal mode from within a transaction",
          (eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
      );
      goto abort_due_to_error;
    }else{

      if( eOld==PAGER_JOURNALMODE_WAL ){

        /* If leaving WAL mode, close the log file. If successful, the call
        ** to PagerCloseWal() checkpoints and deletes the write-ahead-log
        ** file. An EXCLUSIVE lock may still be held on the database file
        ** after a successful return.
        */
        rc = sqlite3PagerCloseWal(pPager, db);
        if( rc==SQLITE_OK ){
          sqlite3PagerSetJournalMode(pPager, eNew);
        }
      }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
        /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
        ** as an intermediate */
        sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
      }
 
      /* Open a transaction on the database file. Regardless of the journal
      ** mode, this transaction always uses a rollback journal.
      */
      assert( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE );
      if( rc==SQLITE_OK ){

        rc = sqlite3BtreeSetVersion(pBt, (eNew==PAGER_JOURNALMODE_WAL ? 2 : 1));


      }
    }
  }
#endif /* ifndef SQLITE_OMIT_WAL */

  if( rc ) eNew = eOld;
  eNew = sqlite3PagerSetJournalMode(pPager, eNew);








>


















|






|
|
>
>
>
>
>
|
>
>
>
>







<
|
|
>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
>
|
>
>
|







7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923

7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
  eNew = pOp->p3;
  assert( eNew==PAGER_JOURNALMODE_DELETE
       || eNew==PAGER_JOURNALMODE_TRUNCATE
       || eNew==PAGER_JOURNALMODE_PERSIST
       || eNew==PAGER_JOURNALMODE_OFF
       || eNew==PAGER_JOURNALMODE_MEMORY
       || eNew==PAGER_JOURNALMODE_WAL
       || eNew==PAGER_JOURNALMODE_WAL2
       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( p->readOnly==0 );

  pBt = db->aDb[pOp->p1].pBt;
  pPager = sqlite3BtreePager(pBt);
  eOld = sqlite3PagerGetJournalMode(pPager);
  if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
  assert( sqlite3BtreeHoldsMutex(pBt) );
  if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;

#ifndef SQLITE_OMIT_WAL
  zFilename = sqlite3PagerFilename(pPager, 1);

  /* Do not allow a transition to journal_mode=WAL for a database
  ** in temporary storage or if the VFS does not support shared memory
  */
  if( isWalMode(eNew)
   && (sqlite3Strlen30(zFilename)==0           /* Temp file */
       || !sqlite3PagerWalSupported(pPager))   /* No shared-memory support */
  ){
    eNew = eOld;
  }

  if( eNew!=eOld && (isWalMode(eNew) || isWalMode(eOld)) ){

    /* Prevent changing directly to wal2 from wal mode. And vice versa. */
    if( isWalMode(eNew) && isWalMode(eOld) ){
      rc = SQLITE_ERROR;
      sqlite3VdbeError(p, "cannot change from %s to %s mode",
          sqlite3JournalModename(eOld), sqlite3JournalModename(eNew)
      );
      goto abort_due_to_error;
    }

    /* Prevent switching into or out of wal/wal2 mode mid-transaction */
    if( !db->autoCommit || db->nVdbeRead>1 ){
      rc = SQLITE_ERROR;
      sqlite3VdbeError(p,
          "cannot change %s wal mode from within a transaction",
          (eNew==PAGER_JOURNALMODE_WAL ? "into" : "out of")
      );
      goto abort_due_to_error;

    }
 
    if( isWalMode(eOld) ){
      /* If leaving WAL mode, close the log file. If successful, the call
      ** to PagerCloseWal() checkpoints and deletes the write-ahead-log 
      ** file. An EXCLUSIVE lock may still be held on the database file 
      ** after a successful return. 
      */
      rc = sqlite3PagerCloseWal(pPager, db);
      if( rc==SQLITE_OK ){
        sqlite3PagerSetJournalMode(pPager, eNew);
      }
    }else if( eOld==PAGER_JOURNALMODE_MEMORY ){
      /* Cannot transition directly from MEMORY to WAL.  Use mode OFF
      ** as an intermediate */
      sqlite3PagerSetJournalMode(pPager, PAGER_JOURNALMODE_OFF);
    }

    /* Open a transaction on the database file. Regardless of the journal
    ** mode, this transaction always uses a rollback journal.
    */
    assert( sqlite3BtreeTxnState(pBt)!=SQLITE_TXN_WRITE );
    if( rc==SQLITE_OK ){
      /* 1==rollback, 2==wal, 3==wal2 */
      rc = sqlite3BtreeSetVersion(pBt, 
          1 + isWalMode(eNew) + (eNew==PAGER_JOURNALMODE_WAL2)
      );

    }
  }
#endif /* ifndef SQLITE_OMIT_WAL */

  if( rc ) eNew = eOld;
  eNew = sqlite3PagerSetJournalMode(pPager, eNew);

Changes to src/vdbeaux.c.

2926
2927
2928
2929
2930
2931
2932
2933

2934
2935
2936
2937
2938
2939
2940
      ** journal modes use a super-journal and which do not */
      static const u8 aMJNeeded[] = {
        /* DELETE   */  1,
        /* PERSIST   */ 1,
        /* OFF       */ 0,
        /* TRUNCATE  */ 1,
        /* MEMORY    */ 0,
        /* WAL       */ 0

      };
      Pager *pPager;   /* Pager associated with pBt */
      needXcommit = 1;
      sqlite3BtreeEnter(pBt);
      pPager = sqlite3BtreePager(pBt);
      if( db->aDb[i].safety_level!=PAGER_SYNCHRONOUS_OFF
       && aMJNeeded[sqlite3PagerGetJournalMode(pPager)]







|
>







2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
      ** journal modes use a super-journal and which do not */
      static const u8 aMJNeeded[] = {
        /* DELETE   */  1,
        /* PERSIST   */ 1,
        /* OFF       */ 0,
        /* TRUNCATE  */ 1,
        /* MEMORY    */ 0,
        /* WAL       */ 0,
        /* WAL2      */ 0
      };
      Pager *pPager;   /* Pager associated with pBt */
      needXcommit = 1;
      sqlite3BtreeEnter(pBt);
      pPager = sqlite3BtreePager(pBt);
      if( db->aDb[i].safety_level!=PAGER_SYNCHRONOUS_OFF
       && aMJNeeded[sqlite3PagerGetJournalMode(pPager)]

Changes to src/wal.c.

97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
** being considered valid at the same time and being checkpointing together
** following a crash.
**
** READER ALGORITHM
**
** To read a page from the database (call it page number P), a reader
** first checks the WAL to see if it contains page P.  If so, then the
** last valid instance of page P that is a followed by a commit frame
** or is a commit frame itself becomes the value read.  If the WAL
** contains no copies of page P that are valid and which are a commit
** frame or are followed by a commit frame, then page P is read from
** the database file.
**
** To start a read transaction, the reader records the index of the last
** valid frame in the WAL.  The reader uses this recorded "mxFrame" value







|







97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
** being considered valid at the same time and being checkpointing together
** following a crash.
**
** READER ALGORITHM
**
** To read a page from the database (call it page number P), a reader
** first checks the WAL to see if it contains page P.  If so, then the
** last valid instance of page P that is followed by a commit frame
** or is a commit frame itself becomes the value read.  If the WAL
** contains no copies of page P that are valid and which are a commit
** frame or are followed by a commit frame, then page P is read from
** the database file.
**
** To start a read transaction, the reader records the index of the last
** valid frame in the WAL.  The reader uses this recorded "mxFrame" value
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
























































































































































































250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277

278
279
280
281
282
283
284
285
**
** Note that entries are added in order of increasing K.  Hence, one
** reader might be using some value K0 and a second reader that started
** at a later time (after additional transactions were added to the WAL
** and to the wal-index) might be using a different value K1, where K1>K0.
** Both readers can use the same hash table and mapping section to get
** the correct result.  There may be entries in the hash table with
** K>K0 but to the first reader, those entries will appear to be unused
** slots in the hash table and so the first reader will get an answer as
** if no values greater than K0 had ever been inserted into the hash table
** in the first place - which is what reader one wants.  Meanwhile, the
** second reader using K1 will see additional values that were inserted
** later, which is exactly what reader two wants.
**
** When a rollback occurs, the value of K is decreased. Hash table entries
** that correspond to frames greater than the new K value are removed
** from the hash table at this point.
*/
























































































































































































#ifndef SQLITE_OMIT_WAL

#include "wal.h"

/*
** Trace output macros
*/
#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
int sqlite3WalTrace = 0;
# define WALTRACE(X)  if(sqlite3WalTrace) sqlite3DebugPrintf X
#else
# define WALTRACE(X)
#endif

/*
** The maximum (and only) versions of the wal and wal-index formats
** that may be interpreted by this version of SQLite.
**
** If a client begins recovering a WAL file and finds that (a) the checksum
** values in the wal-header are correct and (b) the version field is not
** WAL_MAX_VERSION, recovery fails and SQLite returns SQLITE_CANTOPEN.
**
** Similarly, if a client successfully reads a wal-index header (i.e. the
** checksum test is successful) and finds that the version field is not
** WALINDEX_MAX_VERSION, then no read-transaction is opened and SQLite
** returns SQLITE_CANTOPEN.
*/
#define WAL_MAX_VERSION      3007000

#define WALINDEX_MAX_VERSION 3007000

/*
** Index numbers for various locking bytes.   WAL_NREADER is the number
** of available reader locks and should be at least 3.  The default
** is SQLITE_SHM_NLOCK==8 and  WAL_NREADER==5.
**
** Technically, the various VFSes are free to implement these locks however







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**
** Note that entries are added in order of increasing K.  Hence, one
** reader might be using some value K0 and a second reader that started
** at a later time (after additional transactions were added to the WAL
** and to the wal-index) might be using a different value K1, where K1>K0.
** Both readers can use the same hash table and mapping section to get
** the correct result.  There may be entries in the hash table with
** K>K0, but to the first reader those entries will appear to be unused
** slots in the hash table and so the first reader will get an answer as
** if no values greater than K0 had ever been inserted into the hash table
** in the first place - which is what reader one wants.  Meanwhile, the
** second reader using K1 will see additional values that were inserted
** later, which is exactly what reader two wants.
**
** When a rollback occurs, the value of K is decreased. Hash table entries
** that correspond to frames greater than the new K value are removed
** from the hash table at this point.
*/

/*
** WAL2 NOTES
**
** This file also contains the implementation of "wal2" mode - activated
** using "PRAGMA journal_mode = wal2". Wal2 mode is very similar to wal
** mode, except that it uses two wal files instead of one. Under some
** circumstances, wal2 mode provides more concurrency than legacy wal 
** mode.
**
** THE PROBLEM WAL2 SOLVES:
**
** In legacy wal mode, if a writer wishes to write to the database while
** a checkpoint is ongoing, it may append frames to the existing wal file.
** This means that after the checkpoint has finished, the wal file consists
** of a large block of checkpointed frames, followed by a block of
** uncheckpointed frames. In a deployment that features a high volume of
** write traffic, this may mean that the wal file is never completely
** checkpointed. And so grows indefinitely.
**
** An alternative is to use "PRAGMA wal_checkpoint=RESTART" or similar to
** force a complete checkpoint of the wal file. But this must:
**
**   1) Wait on all existing readers to finish,
**   2) Wait on any existing writer, and then block all new writers,
**   3) Do the checkpoint,
**   4) Wait on any new readers that started during steps 2 and 3. Writers
**      are still blocked during this step.
**
** This means that in order to avoid the wal file growing indefinitely 
** in a busy system, writers must periodically pause to allow a checkpoint
** to complete. In a system with long running readers, such pauses may be
** for a non-trivial amount of time.
**
** OVERVIEW OF SOLUTION
**
** Wal2 mode uses two wal files. After writers have grown the first wal 
** file to a pre-configured size, they begin appending transactions to 
** the second wal file. Once all existing readers are reading snapshots
** new enough to include the entire first wal file, a checkpointer can
** checkpoint it.
**
** Meanwhile, writers are writing transactions to the second wal file.
** Once that wal file has grown larger than the pre-configured size, each
** new writer checks if:
**
**    * the first wal file has been checkpointed, and if so, if
**    * there are no readers still reading from the first wal file (once
**      it has been checkpointed, new readers read only from the second
**      wal file).
**
** If both these conditions are true, the writer may switch back to the
** first wal file. Eventually, a checkpointer can checkpoint the second
** wal file, and so on.
**
** The wal file that writers are currently appending to (the one they
** don't have to check the above two criteria before writing to) is called
** the "current" wal file.
**
** The first wal file takes the same name as the wal file in legacy wal
** mode systems - "<db>-wal". The second is named "<db>-wal2".
**
** CHECKPOINTS
**
** The "pre-configured size" mentioned above is the value set by 
** "PRAGMA journal_size_limit". Or, if journal_size_limit is not set, 
** 1000 pages.
**
** There is only a single type of checkpoint in wal2 mode (no "truncate",
** "restart" etc.), and it always checkpoints the entire contents of a single
** wal file. A wal file cannot be checkpointed until after a writer has written
** the first transaction into the other wal file and all readers are reading a
** snapshot that includes at least one transaction from the other wal file.
**
** The wal-hook, if one is registered, is invoked after a write-transaction
** is committed, just as it is in legacy wal mode. The integer parameter
** passed to the wal-hook is the total number of uncheckpointed frames in both
** wal files. Except, the parameter is set to zero if there is no frames 
** that may be checkpointed. This happens in two scenarios:
**
**   1. The "other" wal file (the one that the writer did not just append to)
**      is completely empty, or
**
**   2. The "other" wal file (the one that the writer did not just append to)
**      has already been checkpointed.
**
**
** WAL FILE FORMAT
**
** The file format used for each wal file in wal2 mode is the same as for
** legacy wal mode.  Except, the file format field is set to 3021000 
** instead of 3007000.
**
** WAL-INDEX FORMAT
**
** The wal-index format is also very similar. Even though there are two
** wal files, there is still a single wal-index shared-memory area (*-shm
** file with the default unix or win32 VFS). The wal-index header is the
** same size, with the following exceptions it has the same format:
**
**   * The version field is set to 3021000 instead of 3007000.
**
**   * An unused 32-bit field in the legacy wal-index header is
**     now used to store (a) a single bit indicating which of the
**     two wal files writers should append to and (b) the number
**     of frames in the second wal file (31 bits).
**
** The first hash table in the wal-index contains entries corresponding
** to the first HASHTABLE_NPAGE_ONE frames stored in the first wal file.
** The second hash table in the wal-index contains entries indexing the
** first HASHTABLE_NPAGE frames in the second wal file. The third hash
** table contains the next HASHTABLE_NPAGE frames in the first wal file,
** and so on.
**
** LOCKS
**
** Read-locks are simpler than for legacy wal mode. There are no locking
** slots that contain frame numbers. Instead, there are four distinct
** combinations of read locks a reader may hold:
**
**   WAL_LOCK_PART1:       "part" lock on first wal, none of second.
**   WAL_LOCK_PART1_FULL2: "part" lock on first wal, "full" of second.
**   WAL_LOCK_PART2: no lock on first wal, "part" lock on second.
**   WAL_LOCK_PART2_FULL1: "full" lock on first wal, "part" lock on second.
**
** When a reader reads the wal-index header as part of opening a read
** transaction, it takes a "part" lock on the current wal file. "Part" 
** because the wal file may grow while the read transaction is active, in 
** which case the reader would be reading only part of the wal file. 
** A part lock prevents a checkpointer from checkpointing the wal file 
** on which it is held.
**
** If there is data in the non-current wal file that has not been 
** checkpointed, the reader takes a "full" lock on that wal file. A 
** "full" lock indicates that the reader is using the entire wal file.
** A full lock prevents a writer from overwriting the wal file on which
** it is held, but does not prevent a checkpointer from checkpointing 
** it.
**
** There is still a single WRITER and a single CHECKPOINTER lock. The
** recovery procedure still takes the same exclusive lock on the entire
** range of SQLITE_SHM_NLOCK shm-locks. This works because the read-locks
** above use four of the six read-locking slots used by legacy wal mode.
**
** STARTUP/RECOVERY
**
** The read and write version fields of the database header in a wal2
** database are set to 0x03, instead of 0x02 as in legacy wal mode.
**
** The wal file format used in wal2 mode is the same as the format used
** in legacy wal mode. However, in order to support recovery, there are two
** differences in the way wal file header fields are populated, as follows:
**
**   * When the first wal file is first created, the "nCkpt" field in
**     the wal file header is set to 0. Thereafter, each time the writer
**     switches wal file, it sets the nCkpt field in the new wal file
**     header to ((nCkpt0 + 1) & 0x0F), where nCkpt0 is the value in
**     the previous wal file header. This means that the first wal file
**     always has an even value in the nCkpt field, and the second wal
**     file always has an odd value.
**
**   * When a writer switches wal file, it sets the salt values in the
**     new wal file to a copy of the checksum for the final frame in
**     the previous wal file.
**
** Recovery proceeds as follows:
**
** 1. Each wal file is recovered separately. Except, if the first wal 
**    file does not exist or is zero bytes in size, the second wal file
**    is truncated to zero bytes before it is "recovered".
**
** 2. If both wal files contain valid headers, then the nCkpt fields
**    are compared to see which of the two wal files is older. If the
**    salt keys in the second wal file match the final frame checksum 
**    in the older wal file, then both wal files are used. Otherwise,
**    the newer wal file is ignored.
**
** 3. Or, if only one or neither of the wal files has a valid header, 
**    then only a single or no wal files are recovered into the 
**    reconstructed wal-index.
**
** Refer to header comments for walIndexRecover() for further details.
*/

#ifndef SQLITE_OMIT_WAL

#include "wal.h"

/*
** Trace output macros
*/
#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
int sqlite3WalTrace = 0;
# define WALTRACE(X)  if(sqlite3WalTrace) sqlite3DebugPrintf X
#else
# define WALTRACE(X)
#endif

/*
** Both the wal-file and the wal-index contain version fields 
** indicating the current version of the system. If a client
** reads the header of a wal file (as part of recovery), or the
** wal-index (as part of opening a read transaction) and (a) the
** header checksum is correct but (b) the version field is not
** recognized, the operation fails with SQLITE_CANTOPEN.
**
** Currently, clients support both version-1 ("journal_mode=wal") and
** version-2 ("journal_mode=wal2"). Legacy clients may support version-1

** only.
*/
#define WAL_VERSION1 3007000      /* For "journal_mode=wal" */
#define WAL_VERSION2 3021000      /* For "journal_mode=wal2" */


/*
** Index numbers for various locking bytes.   WAL_NREADER is the number
** of available reader locks and should be at least 3.  The default
** is SQLITE_SHM_NLOCK==8 and  WAL_NREADER==5.
**
** Technically, the various VFSes are free to implement these locks however
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#define WAL_WRITE_LOCK         0
#define WAL_ALL_BUT_WRITE      1
#define WAL_CKPT_LOCK          1
#define WAL_RECOVER_LOCK       2
#define WAL_READ_LOCK(I)       (3+(I))
#define WAL_NREADER            (SQLITE_SHM_NLOCK-3)



































/* Object declarations */
typedef struct WalIndexHdr WalIndexHdr;
typedef struct WalIterator WalIterator;
typedef struct WalCkptInfo WalCkptInfo;


/*
** The following object holds a copy of the wal-index header content.
**
** The actual header in the wal-index consists of two copies of this
** object followed by one instance of the WalCkptInfo object.
** For all versions of SQLite through 3.10.0 and probably beyond,
** the locking bytes (WalCkptInfo.aLock) start at offset 120 and
** the total header size is 136 bytes.
**
** The szPage value can be any power of 2 between 512 and 32768, inclusive.
** Or it can be 1 to represent a 65536-byte page.  The latter case was
** added in 3.7.1 when support for 64K pages was added.






*/
struct WalIndexHdr {
  u32 iVersion;                   /* Wal-index version */
  u32 unused;                     /* Unused (padding) field */
  u32 iChange;                    /* Counter incremented each transaction */
  u8 isInit;                      /* 1 when initialized */
  u8 bigEndCksum;                 /* True if checksums in WAL are big-endian */
  u16 szPage;                     /* Database page size in bytes. 1==64K */
  u32 mxFrame;                    /* Index of last valid frame in the WAL */
  u32 nPage;                      /* Size of database in pages */
  u32 aFrameCksum[2];             /* Checksum of last frame in log */
  u32 aSalt[2];                   /* Two salt values copied from WAL header */
  u32 aCksum[2];                  /* Checksum over all prior fields */
};






































/*
** A copy of the following object occurs in the wal-index immediately
** following the second copy of the WalIndexHdr.  This object stores
** information used by checkpoint.
**
** nBackfill is the number of frames in the WAL that have been written
** back into the database. (We call the act of moving content from WAL to







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#define WAL_WRITE_LOCK         0
#define WAL_ALL_BUT_WRITE      1
#define WAL_CKPT_LOCK          1
#define WAL_RECOVER_LOCK       2
#define WAL_READ_LOCK(I)       (3+(I))
#define WAL_NREADER            (SQLITE_SHM_NLOCK-3)

/*
** Values that may be stored in Wal.readLock in wal2 mode.
**
** In wal mode, the Wal.readLock member is set to -1 when no read-lock
** is held, or else is the index of the read-mark on which a lock is
** held.
**
** In wal2 mode, a value of -1 still indicates that no read-lock is held.
** And a non-zero value still represents the index of the read-mark on
** which a lock is held. There are two differences:
**
**   1. wal2 mode never uses read-mark 0.
**
**   2. locks on each read-mark have a different interpretation, as 
**      indicated by the symbolic names below.
*/
#define WAL_LOCK_NONE        -1
#define WAL_LOCK_PART1        1
#define WAL_LOCK_PART1_FULL2  2
#define WAL_LOCK_PART2_FULL1  3
#define WAL_LOCK_PART2        4

/* 
** This constant is used in wal2 mode only.
**
** In wal2 mode, when committing a transaction, if the current wal file 
** is sufficiently large and there are no conflicting locks held, the
** writer writes the new transaction into the start of the other wal
** file. Usually, "sufficiently large" is defined by the value configured
** using "PRAGMA journal_size_limit". However, if no such value has been
** configured, sufficiently large defaults to WAL_DEFAULT_WALSIZE frames.
*/
#define WAL_DEFAULT_WALSIZE 1000

/* Object declarations */
typedef struct WalIndexHdr WalIndexHdr;
typedef struct WalIterator WalIterator;
typedef struct WalCkptInfo WalCkptInfo;


/*
** The following object holds a copy of the wal-index header content.
**
** The actual header in the wal-index consists of two copies of this
** object followed by one instance of the WalCkptInfo object.
** For all versions of SQLite through 3.10.0 and probably beyond,
** the locking bytes (WalCkptInfo.aLock) start at offset 120 and
** the total header size is 136 bytes.
**
** The szPage value can be any power of 2 between 512 and 32768, inclusive.
** Or it can be 1 to represent a 65536-byte page.  The latter case was
** added in 3.7.1 when support for 64K pages was added.
**
** WAL2 mode notes: Member variable mxFrame2 is only used in wal2 mode
** (when iVersion is set to WAL_VERSION2). The lower 31 bits store
** the maximum frame number in file *-wal2. The most significant bit
** is a flag - set if clients are currently appending to *-wal2, clear
** otherwise.
*/
struct WalIndexHdr {
  u32 iVersion;                   /* Wal-index version */
  u32 mxFrame2;                   /* See "WAL2 mode notes" above */
  u32 iChange;                    /* Counter incremented each transaction */
  u8 isInit;                      /* 1 when initialized */
  u8 bigEndCksum;                 /* True if checksums in WAL are big-endian */
  u16 szPage;                     /* Database page size in bytes. 1==64K */
  u32 mxFrame;                    /* Index of last valid frame in each WAL */
  u32 nPage;                      /* Size of database in pages */
  u32 aFrameCksum[2];             /* Checksum of last frame in log */
  u32 aSalt[2];                   /* Two salt values copied from WAL header */
  u32 aCksum[2];                  /* Checksum over all prior fields */
};

/*
** The following macros and functions are get/set methods for the maximum
** frame numbers and current wal file values stored in the WalIndexHdr
** structure. These are helpful because of the unorthodox way in which
** the values are stored in wal2 mode (see above). They are equivalent
** to functions with the following signatures.
**
**   u32  walidxGetMxFrame(WalIndexHdr*, int iWal);          // get mxFrame
**   void walidxSetMxFrame(WalIndexHdr*, int iWal, u32 val); // set mxFrame
**   int  walidxGetFile(WalIndexHdr*)                        // get file
**   void walidxSetFile(WalIndexHdr*, int val);              // set file
*/
#define walidxGetMxFrame(pHdr, iWal) \
  ((iWal) ? ((pHdr)->mxFrame2 & 0x7FFFFFFF) : (pHdr)->mxFrame)

static void walidxSetMxFrame(WalIndexHdr *pHdr, int iWal, u32 mxFrame){
  if( iWal ){
    pHdr->mxFrame2 = (pHdr->mxFrame2 & 0x80000000) | mxFrame;
  }else{
    pHdr->mxFrame = mxFrame;
  }
  assert( walidxGetMxFrame(pHdr, iWal)==mxFrame );
}

#define walidxGetFile(pHdr) ((pHdr)->mxFrame2 >> 31)

#define walidxSetFile(pHdr, iWal) (                                          \
    (pHdr)->mxFrame2 = ((pHdr)->mxFrame2 & 0x7FFFFFFF) | (((u32)(iWal))<<31) \
)

/*
** Argument is a pointer to a Wal structure. Return true if the current
** cache of the wal-index header indicates "journal_mode=wal2" mode, or
** false otherwise.
*/
#define isWalMode2(pWal) ((pWal)->hdr.iVersion==WAL_VERSION2)

/*
** A copy of the following object occurs in the wal-index immediately
** following the second copy of the WalIndexHdr.  This object stores
** information used by checkpoint.
**
** nBackfill is the number of frames in the WAL that have been written
** back into the database. (We call the act of moving content from WAL to
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/*
** An open write-ahead log file is represented by an instance of the
** following object.
*/
struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *pWalFd;      /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
  int nWiData;               /* Size of array apWiData */
  int szFirstBlock;          /* Size of first block written to WAL file */
  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
  u32 szPage;                /* Database page size */
  i16 readLock;              /* Which read lock is being held.  -1 for none */
  u8 syncFlags;              /* Flags to use to sync header writes */
  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
  u8 writeLock;              /* True if in a write transaction */
  u8 ckptLock;               /* True if holding a checkpoint lock */
  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
  u8 syncHeader;             /* Fsync the WAL header if true */
  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
  u8 bShmUnreliable;         /* SHM content is read-only and unreliable */
  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  u32 minFrame;              /* Ignore wal frames before this one */
  u32 iReCksum;              /* On commit, recalculate checksums from here */
  const char *zWalName;      /* Name of WAL file */

  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_USE_SEH
  u32 lockMask;              /* Mask of locks held */
  void *pFree;               /* Pointer to sqlite3_free() if exception thrown */
  u32 *pWiValue;             /* Value to write into apWiData[iWiPg] */
  int iWiPg;                 /* Write pWiValue into apWiData[iWiPg] */
  int iSysErrno;             /* System error code following exception */
#endif
#ifdef SQLITE_DEBUG
  int nSehTry;               /* Number of nested SEH_TRY{} blocks */
  u8 lockError;              /* True if a locking error has occurred */
#endif
#ifdef SQLITE_ENABLE_SNAPSHOT
  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
#endif


#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  sqlite3 *db;
#endif
};

/*
** Candidate values for Wal.exclusiveMode.







|




















>















>
>







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/*
** An open write-ahead log file is represented by an instance of the
** following object.
*/
struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *apWalFd[2];  /* File handle for "*-wal" and "*-wal2" */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
  int nWiData;               /* Size of array apWiData */
  int szFirstBlock;          /* Size of first block written to WAL file */
  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
  u32 szPage;                /* Database page size */
  i16 readLock;              /* Which read lock is being held.  -1 for none */
  u8 syncFlags;              /* Flags to use to sync header writes */
  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
  u8 writeLock;              /* True if in a write transaction */
  u8 ckptLock;               /* True if holding a checkpoint lock */
  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
  u8 syncHeader;             /* Fsync the WAL header if true */
  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
  u8 bShmUnreliable;         /* SHM content is read-only and unreliable */
  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  u32 minFrame;              /* Ignore wal frames before this one */
  u32 iReCksum;              /* On commit, recalculate checksums from here */
  const char *zWalName;      /* Name of WAL file */
  const char *zWalName2;     /* Name of second WAL file */
  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_USE_SEH
  u32 lockMask;              /* Mask of locks held */
  void *pFree;               /* Pointer to sqlite3_free() if exception thrown */
  u32 *pWiValue;             /* Value to write into apWiData[iWiPg] */
  int iWiPg;                 /* Write pWiValue into apWiData[iWiPg] */
  int iSysErrno;             /* System error code following exception */
#endif
#ifdef SQLITE_DEBUG
  int nSehTry;               /* Number of nested SEH_TRY{} blocks */
  u8 lockError;              /* True if a locking error has occurred */
#endif
#ifdef SQLITE_ENABLE_SNAPSHOT
  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
#endif
  int bClosing;              /* Set to true at start of sqlite3WalClose() */
  int bWal2;                 /* bWal2 flag passed to WalOpen() */
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  sqlite3 *db;
#endif
};

/*
** Candidate values for Wal.exclusiveMode.
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618
619

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626
*/
#define HASHTABLE_NPAGE_ONE  (HASHTABLE_NPAGE - (WALINDEX_HDR_SIZE/sizeof(u32)))

/* The wal-index is divided into pages of WALINDEX_PGSZ bytes each. */
#define WALINDEX_PGSZ   (                                         \
    sizeof(ht_slot)*HASHTABLE_NSLOT + HASHTABLE_NPAGE*sizeof(u32) \
)


/*
** Structured Exception Handling (SEH) is a Windows-specific technique
** for catching exceptions raised while accessing memory-mapped files.
**
** The -DSQLITE_USE_SEH compile-time option means to use SEH to catch and
** deal with system-level errors that arise during WAL -shm file processing.







>







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*/
#define HASHTABLE_NPAGE_ONE  (HASHTABLE_NPAGE - (WALINDEX_HDR_SIZE/sizeof(u32)))

/* The wal-index is divided into pages of WALINDEX_PGSZ bytes each. */
#define WALINDEX_PGSZ   (                                         \
    sizeof(ht_slot)*HASHTABLE_NSLOT + HASHTABLE_NPAGE*sizeof(u32) \
)


/*
** Structured Exception Handling (SEH) is a Windows-specific technique
** for catching exceptions raised while accessing memory-mapped files.
**
** The -DSQLITE_USE_SEH compile-time option means to use SEH to catch and
** deal with system-level errors that arise during WAL -shm file processing.
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# define SEH_TRY          VVA_ONLY(pWal->nSehTry++);
# define SEH_EXCEPT(X)    VVA_ONLY(pWal->nSehTry--); assert( pWal->nSehTry==0 );
# define SEH_INJECT_FAULT assert( pWal->nSehTry>0 );
# define SEH_FREE_ON_ERROR(X,Y)
# define SEH_SET_ON_ERROR(X,Y)
#endif /* ifdef SQLITE_USE_SEH */


/*
** Obtain a pointer to the iPage'th page of the wal-index. The wal-index
** is broken into pages of WALINDEX_PGSZ bytes. Wal-index pages are
** numbered from zero.
**
** If the wal-index is currently smaller the iPage pages then the size
** of the wal-index might be increased, but only if it is safe to do







<







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990

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# define SEH_TRY          VVA_ONLY(pWal->nSehTry++);
# define SEH_EXCEPT(X)    VVA_ONLY(pWal->nSehTry--); assert( pWal->nSehTry==0 );
# define SEH_INJECT_FAULT assert( pWal->nSehTry>0 );
# define SEH_FREE_ON_ERROR(X,Y)
# define SEH_SET_ON_ERROR(X,Y)
#endif /* ifdef SQLITE_USE_SEH */


/*
** Obtain a pointer to the iPage'th page of the wal-index. The wal-index
** is broken into pages of WALINDEX_PGSZ bytes. Wal-index pages are
** numbered from zero.
**
** If the wal-index is currently smaller the iPage pages then the size
** of the wal-index might be increased, but only if it is safe to do
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}

/*
** Return a pointer to the WalIndexHdr structure in the wal-index.
*/
static volatile WalIndexHdr *walIndexHdr(Wal *pWal){
  assert( pWal->nWiData>0 && pWal->apWiData[0] );
  SEH_INJECT_FAULT;
  return (volatile WalIndexHdr*)pWal->apWiData[0];
}

/*
** The argument to this macro must be of type u32. On a little-endian
** architecture, it returns the u32 value that results from interpreting
** the 4 bytes as a big-endian value. On a big-endian architecture, it







<







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}

/*
** Return a pointer to the WalIndexHdr structure in the wal-index.
*/
static volatile WalIndexHdr *walIndexHdr(Wal *pWal){
  assert( pWal->nWiData>0 && pWal->apWiData[0] );

  return (volatile WalIndexHdr*)pWal->apWiData[0];
}

/*
** The argument to this macro must be of type u32. On a little-endian
** architecture, it returns the u32 value that results from interpreting
** the 4 bytes as a big-endian value. On a big-endian architecture, it
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*/
static SQLITE_NO_TSAN void walIndexWriteHdr(Wal *pWal){
  volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
  const int nCksum = offsetof(WalIndexHdr, aCksum);

  assert( pWal->writeLock );
  pWal->hdr.isInit = 1;
  pWal->hdr.iVersion = WALINDEX_MAX_VERSION;
  walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
  /* Possible TSAN false-positive.  See tag-20200519-1 */
  memcpy((void*)&aHdr[1], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
  walShmBarrier(pWal);
  memcpy((void*)&aHdr[0], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
}








|







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*/
static SQLITE_NO_TSAN void walIndexWriteHdr(Wal *pWal){
  volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
  const int nCksum = offsetof(WalIndexHdr, aCksum);

  assert( pWal->writeLock );
  pWal->hdr.isInit = 1;
  assert( pWal->hdr.iVersion==WAL_VERSION1||pWal->hdr.iVersion==WAL_VERSION2 );
  walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);
  /* Possible TSAN false-positive.  See tag-20200519-1 */
  memcpy((void*)&aHdr[1], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
  walShmBarrier(pWal);
  memcpy((void*)&aHdr[0], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
}

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      pLoc->iZero = HASHTABLE_NPAGE_ONE + (iHash-1)*HASHTABLE_NPAGE;
    }
  }else if( NEVER(rc==SQLITE_OK) ){
    rc = SQLITE_ERROR;
  }
  return rc;
}

































/*
** Return the number of the wal-index page that contains the hash-table
** and page-number array that contain entries corresponding to WAL frame
** iFrame. The wal-index is broken up into 32KB pages. Wal-index pages
** are numbered starting from 0.
*/
static int walFramePage(u32 iFrame){
  int iHash = (iFrame+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1) / HASHTABLE_NPAGE;
  assert( (iHash==0 || iFrame>HASHTABLE_NPAGE_ONE)
       && (iHash>=1 || iFrame<=HASHTABLE_NPAGE_ONE)
       && (iHash<=1 || iFrame>(HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE))
       && (iHash>=2 || iFrame<=HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE)
       && (iHash<=2 || iFrame>(HASHTABLE_NPAGE_ONE+2*HASHTABLE_NPAGE))
  );
  assert( iHash>=0 );
  return iHash;
}

















/*
** Return the page number associated with frame iFrame in this WAL.
*/
static u32 walFramePgno(Wal *pWal, u32 iFrame){
  int iHash = walFramePage(iFrame);
  SEH_INJECT_FAULT;
  if( iHash==0 ){
    return pWal->apWiData[0][WALINDEX_HDR_SIZE/sizeof(u32) + iFrame - 1];
  }
  return pWal->apWiData[iHash][(iFrame-1-HASHTABLE_NPAGE_ONE)%HASHTABLE_NPAGE];
}





/*
** Remove entries from the hash table that point to WAL slots greater
** than pWal->hdr.mxFrame.
**
** This function is called whenever pWal->hdr.mxFrame is decreased due
** to a rollback or savepoint.
**
** At most only the hash table containing pWal->hdr.mxFrame needs to be
** updated.  Any later hash tables will be automatically cleared when
** pWal->hdr.mxFrame advances to the point where those hash tables are
** actually needed.
*/
static void walCleanupHash(Wal *pWal){
  WalHashLoc sLoc;                /* Hash table location */
  int iLimit = 0;                 /* Zero values greater than this */
  int nByte;                      /* Number of bytes to zero in aPgno[] */
  int i;                          /* Used to iterate through aHash[] */











  assert( pWal->writeLock );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE-1 );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE );
  testcase( pWal->hdr.mxFrame==HASHTABLE_NPAGE_ONE+1 );

  if( pWal->hdr.mxFrame==0 ) return;

  /* Obtain pointers to the hash-table and page-number array containing
  ** the entry that corresponds to frame pWal->hdr.mxFrame. It is guaranteed
  ** that the page said hash-table and array reside on is already mapped.(1)
  */
  assert( pWal->nWiData>walFramePage(pWal->hdr.mxFrame) );
  assert( pWal->apWiData[walFramePage(pWal->hdr.mxFrame)] );
  i = walHashGet(pWal, walFramePage(pWal->hdr.mxFrame), &sLoc);
  if( NEVER(i) ) return; /* Defense-in-depth, in case (1) above is wrong */

  /* Zero all hash-table entries that correspond to frame numbers greater
  ** than pWal->hdr.mxFrame.
  */
  iLimit = pWal->hdr.mxFrame - sLoc.iZero;
  assert( iLimit>0 );
  for(i=0; i<HASHTABLE_NSLOT; i++){
    if( sLoc.aHash[i]>iLimit ){
      sLoc.aHash[i] = 0;
    }
  }








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|





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|





|







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      pLoc->iZero = HASHTABLE_NPAGE_ONE + (iHash-1)*HASHTABLE_NPAGE;
    }
  }else if( NEVER(rc==SQLITE_OK) ){
    rc = SQLITE_ERROR;
  }
  return rc;
}

static u32 walExternalEncode(int iWal, u32 iFrame){
  u32 iRet;
  if( iWal ){
    iRet = HASHTABLE_NPAGE_ONE + iFrame;
    iRet += ((iFrame-1) / HASHTABLE_NPAGE) * HASHTABLE_NPAGE;
  }else{
    iRet = iFrame;
    iFrame += HASHTABLE_NPAGE - HASHTABLE_NPAGE_ONE;
    iRet += ((iFrame-1) / HASHTABLE_NPAGE) * HASHTABLE_NPAGE;
  }
  return iRet;
}

/*
** Parameter iExternal is an external frame identifier. This function
** transforms it to a wal file number (0 or 1) and frame number within
** this wal file (reported via output parameter *piRead).
*/
static int walExternalDecode(u32 iExternal, u32 *piRead){
  int iHash = (iExternal+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1)/HASHTABLE_NPAGE;

  if( 0==(iHash & 0x01) ){
    /* A frame in wal file 0 */
    *piRead = (iExternal <= HASHTABLE_NPAGE_ONE) ? iExternal :
      iExternal - (iHash/2) * HASHTABLE_NPAGE;
    return 0;
  }

  *piRead = iExternal - HASHTABLE_NPAGE_ONE - ((iHash-1)/2) * HASHTABLE_NPAGE;
  return 1;
}

/*
** Return the number of the wal-index page that contains the hash-table
** and page-number array that contain entries corresponding to WAL frame
** iFrame. The wal-index is broken up into 32KB pages. Wal-index pages
** are numbered starting from 0.
*/
static int walFramePage(u32 iFrame){
  int iHash = (iFrame+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1) / HASHTABLE_NPAGE;
  assert( (iHash==0 || iFrame>HASHTABLE_NPAGE_ONE)
       && (iHash>=1 || iFrame<=HASHTABLE_NPAGE_ONE)
       && (iHash<=1 || iFrame>(HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE))
       && (iHash>=2 || iFrame<=HASHTABLE_NPAGE_ONE+HASHTABLE_NPAGE)
       && (iHash<=2 || iFrame>(HASHTABLE_NPAGE_ONE+2*HASHTABLE_NPAGE))
  );
  assert( iHash>=0 );
  return iHash;
}

/*
** Return the index of the hash-table corresponding to frame iFrame of wal
** file iWal.
*/
static int walFramePage2(int iWal, u32 iFrame){
  int iRet;
  assert( iWal==0 || iWal==1 );
  assert( iFrame>0 );
  if( iWal==0 ){
    iRet = 2*((iFrame+HASHTABLE_NPAGE-HASHTABLE_NPAGE_ONE-1)/HASHTABLE_NPAGE);
  }else{
    iRet = 1 + 2 * ((iFrame-1) / HASHTABLE_NPAGE);
  }
  return iRet;
}

/*
** Return the page number associated with frame iFrame in this WAL.
*/
static u32 walFramePgno(Wal *pWal, u32 iFrame){
  int iHash = walFramePage(iFrame);
  SEH_INJECT_FAULT;
  if( iHash==0 ){
    return pWal->apWiData[0][WALINDEX_HDR_SIZE/sizeof(u32) + iFrame - 1];
  }
  return pWal->apWiData[iHash][(iFrame-1-HASHTABLE_NPAGE_ONE)%HASHTABLE_NPAGE];
}

static u32 walFramePgno2(Wal *pWal, int iWal, u32 iFrame){
  return walFramePgno(pWal, walExternalEncode(iWal, iFrame));
}

/*
** Remove entries from the hash table that point to WAL slots greater
** than pWal->hdr.mxFrame.
**
** This function is called whenever pWal->hdr.mxFrame is decreased due
** to a rollback or savepoint.
**
** At most only the hash table containing pWal->hdr.mxFrame needs to be
** updated.  Any later hash tables will be automatically cleared when
** pWal->hdr.mxFrame advances to the point where those hash tables are
** actually needed.
*/
static void walCleanupHash(Wal *pWal){
  WalHashLoc sLoc;                /* Hash table location */
  int iLimit = 0;                 /* Zero values greater than this */
  int nByte;                      /* Number of bytes to zero in aPgno[] */
  int i;                          /* Used to iterate through aHash[] */
  int iWal = walidxGetFile(&pWal->hdr);
  u32 mxFrame = walidxGetMxFrame(&pWal->hdr, iWal);

  u32 iExternal;
  if( isWalMode2(pWal) ){
    iExternal = walExternalEncode(iWal, mxFrame);
  }else{
    assert( iWal==0 );
    iExternal = mxFrame;
  }

  assert( pWal->writeLock );
  testcase( mxFrame==HASHTABLE_NPAGE_ONE-1 );
  testcase( mxFrame==HASHTABLE_NPAGE_ONE );
  testcase( mxFrame==HASHTABLE_NPAGE_ONE+1 );

  if( mxFrame==0 ) return;

  /* Obtain pointers to the hash-table and page-number array containing
  ** the entry that corresponds to frame pWal->hdr.mxFrame. It is guaranteed
  ** that the page said hash-table and array reside on is already mapped.(1)
  */
  assert( pWal->nWiData>walFramePage(iExternal) );
  assert( pWal->apWiData[walFramePage(iExternal)] );
  i = walHashGet(pWal, walFramePage(iExternal), &sLoc);
  if( NEVER(i) ) return; /* Defense-in-depth, in case (1) above is wrong */

  /* Zero all hash-table entries that correspond to frame numbers greater
  ** than pWal->hdr.mxFrame.
  */
  iLimit = iExternal - sLoc.iZero;
  assert( iLimit>0 );
  for(i=0; i<HASHTABLE_NSLOT; i++){
    if( sLoc.aHash[i]>iLimit ){
      sLoc.aHash[i] = 0;
    }
  }

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      }
      assert( sLoc.aHash[iKey]==j+1 );
    }
  }
#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
}


/*
** Set an entry in the wal-index that will map database page number
** pPage into WAL frame iFrame.
*/
static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
  int rc;                         /* Return code */
  WalHashLoc sLoc;                /* Wal-index hash table location */









  rc = walHashGet(pWal, walFramePage(iFrame), &sLoc);

  /* Assuming the wal-index file was successfully mapped, populate the
  ** page number array and hash table entry.
  */
  if( rc==SQLITE_OK ){
    int iKey;                     /* Hash table key */
    int idx;                      /* Value to write to hash-table slot */
    int nCollide;                 /* Number of hash collisions */

    idx = iFrame - sLoc.iZero;
    assert( idx <= HASHTABLE_NSLOT/2 + 1 );

    /* If this is the first entry to be added to this hash-table, zero the
    ** entire hash table and aPgno[] array before proceeding.
    */
    if( idx==1 ){
      int nByte = (int)((u8*)&sLoc.aHash[HASHTABLE_NSLOT] - (u8*)sLoc.aPgno);







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      }
      assert( sLoc.aHash[iKey]==j+1 );
    }
  }
#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
}


/*
** Set an entry in the wal-index that will map database page number
** pPage into WAL frame iFrame.
*/
static int walIndexAppend(Wal *pWal, int iWal, u32 iFrame, u32 iPage){
  int rc;                         /* Return code */
  WalHashLoc sLoc;                /* Wal-index hash table location */
  u32 iExternal;
  
  if( isWalMode2(pWal) ){
    iExternal = walExternalEncode(iWal, iFrame);
  }else{
    assert( iWal==0 );
    iExternal = iFrame;
  }

  rc = walHashGet(pWal, walFramePage(iExternal), &sLoc);

  /* Assuming the wal-index file was successfully mapped, populate the
  ** page number array and hash table entry.
  */
  if( rc==SQLITE_OK ){
    int iKey;                     /* Hash table key */
    int idx;                      /* Value to write to hash-table slot */
    int nCollide;                 /* Number of hash collisions */

    idx = iExternal - sLoc.iZero;
    assert( idx <= HASHTABLE_NSLOT/2 + 1 );

    /* If this is the first entry to be added to this hash-table, zero the
    ** entire hash table and aPgno[] array before proceeding.
    */
    if( idx==1 ){
      int nByte = (int)((u8*)&sLoc.aHash[HASHTABLE_NSLOT] - (u8*)sLoc.aPgno);
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    }
#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
  }

  return rc;
}





















































































































































































































/*
** Recover the wal-index by reading the write-ahead log file.
**
** This routine first tries to establish an exclusive lock on the
** wal-index to prevent other threads/processes from doing anything
** with the WAL or wal-index while recovery is running.  The
** WAL_RECOVER_LOCK is also held so that other threads will know
** that this thread is running recovery.  If unable to establish
** the necessary locks, this routine returns SQLITE_BUSY.
*/
static int walIndexRecover(Wal *pWal){
  int rc;                         /* Return Code */
  i64 nSize;                      /* Size of log file */
  u32 aFrameCksum[2] = {0, 0};
  int iLock;                      /* Lock offset to lock for checkpoint */





  /* Obtain an exclusive lock on all byte in the locking range not already
  ** locked by the caller. The caller is guaranteed to have locked the
  ** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
  ** If successful, the same bytes that are locked here are unlocked before
  ** this function returns.
  */
  assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
  assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
  assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
  assert( pWal->writeLock );
  iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
  rc = walLockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
  if( rc ){
    return rc;
  }

  WALTRACE(("WAL%p: recovery begin...\n", pWal));

  memset(&pWal->hdr, 0, sizeof(WalIndexHdr));

  rc = sqlite3OsFileSize(pWal->pWalFd, &nSize);
  if( rc!=SQLITE_OK ){
    goto recovery_error;
  }

  if( nSize>WAL_HDRSIZE ){
    u8 aBuf[WAL_HDRSIZE];         /* Buffer to load WAL header into */
    u32 *aPrivate = 0;            /* Heap copy of *-shm hash being populated */
    u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
    int szFrame;                  /* Number of bytes in buffer aFrame[] */
    u8 *aData;                    /* Pointer to data part of aFrame buffer */
    int szPage;                   /* Page size according to the log */
    u32 magic;                    /* Magic value read from WAL header */
    u32 version;                  /* Magic value read from WAL header */
    int isValid;                  /* True if this frame is valid */
    u32 iPg;                      /* Current 32KB wal-index page */
    u32 iLastFrame;               /* Last frame in wal, based on nSize alone */

    /* Read in the WAL header. */
    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      goto recovery_error;
    }

    /* If the database page size is not a power of two, or is greater than
    ** SQLITE_MAX_PAGE_SIZE, conclude that the WAL file contains no valid
    ** data. Similarly, if the 'magic' value is invalid, ignore the whole
    ** WAL file.
    */
    magic = sqlite3Get4byte(&aBuf[0]);
    szPage = sqlite3Get4byte(&aBuf[8]);
    if( (magic&0xFFFFFFFE)!=WAL_MAGIC
     || szPage&(szPage-1)
     || szPage>SQLITE_MAX_PAGE_SIZE
     || szPage<512
    ){


      goto finished;
    }
    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
    pWal->szPage = szPage;
    pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
    memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);

    /* Verify that the WAL header checksum is correct */
    walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN,
        aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
    );
    if( pWal->hdr.aFrameCksum[0]!=sqlite3Get4byte(&aBuf[24])
     || pWal->hdr.aFrameCksum[1]!=sqlite3Get4byte(&aBuf[28])
    ){
      goto finished;
    }

    /* Verify that the version number on the WAL format is one that
    ** are able to understand */
    version = sqlite3Get4byte(&aBuf[4]);
    if( version!=WAL_MAX_VERSION ){
      rc = SQLITE_CANTOPEN_BKPT;
      goto finished;
    }

    /* Malloc a buffer to read frames into. */
    szFrame = szPage + WAL_FRAME_HDRSIZE;
    aFrame = (u8 *)sqlite3_malloc64(szFrame + WALINDEX_PGSZ);
    SEH_FREE_ON_ERROR(0, aFrame);
    if( !aFrame ){
      rc = SQLITE_NOMEM_BKPT;

      goto recovery_error;
    }
    aData = &aFrame[WAL_FRAME_HDRSIZE];
    aPrivate = (u32*)&aData[szPage];

    /* Read all frames from the log file. */
    iLastFrame = (nSize - WAL_HDRSIZE) / szFrame;
    for(iPg=0; iPg<=(u32)walFramePage(iLastFrame); iPg++){
      u32 *aShare;
      u32 iFrame;                 /* Index of last frame read */
      u32 iLast = MIN(iLastFrame, HASHTABLE_NPAGE_ONE+iPg*HASHTABLE_NPAGE);
      u32 iFirst = 1 + (iPg==0?0:HASHTABLE_NPAGE_ONE+(iPg-1)*HASHTABLE_NPAGE);
      u32 nHdr, nHdr32;
      rc = walIndexPage(pWal, iPg, (volatile u32**)&aShare);

      assert( aShare!=0 || rc!=SQLITE_OK );
      if( aShare==0 ) break;
      SEH_SET_ON_ERROR(iPg, aShare);
      pWal->apWiData[iPg] = aPrivate;

      for(iFrame=iFirst; iFrame<=iLast; iFrame++){
        i64 iOffset = walFrameOffset(iFrame, szPage);
        u32 pgno;                 /* Database page number for frame */
        u32 nTruncate;            /* dbsize field from frame header */






        /* Read and decode the next log frame. */

        rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
        if( rc!=SQLITE_OK ) break;
        isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
        if( !isValid ) break;
        rc = walIndexAppend(pWal, iFrame, pgno);
        if( NEVER(rc!=SQLITE_OK) ) break;

        /* If nTruncate is non-zero, this is a commit record. */
        if( nTruncate ){
          pWal->hdr.mxFrame = iFrame;
          pWal->hdr.nPage = nTruncate;
          pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
          testcase( szPage<=32768 );
          testcase( szPage>=65536 );
          aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
          aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
        }
      }
      pWal->apWiData[iPg] = aShare;
      SEH_SET_ON_ERROR(0,0);
      nHdr = (iPg==0 ? WALINDEX_HDR_SIZE : 0);
      nHdr32 = nHdr / sizeof(u32);
#ifndef SQLITE_SAFER_WALINDEX_RECOVERY
      /* Memcpy() should work fine here, on all reasonable implementations.
      ** Technically, memcpy() might change the destination to some
      ** intermediate value before setting to the final value, and that might
      ** cause a concurrent reader to malfunction.  Memcpy() is allowed to
      ** do that, according to the spec, but no memcpy() implementation that
      ** we know of actually does that, which is why we say that memcpy()
      ** is safe for this.  Memcpy() is certainly a lot faster.
      */
      memcpy(&aShare[nHdr32], &aPrivate[nHdr32], WALINDEX_PGSZ-nHdr);
#else
      /* In the event that some platform is found for which memcpy()
      ** changes the destination to some intermediate value before
      ** setting the final value, this alternative copy routine is
      ** provided.
      */
      {
        int i;
        for(i=nHdr32; i<WALINDEX_PGSZ/sizeof(u32); i++){
          if( aShare[i]!=aPrivate[i] ){
            /* Atomic memory operations are not required here because if
            ** the value needs to be changed, that means it is not being
            ** accessed concurrently. */
            aShare[i] = aPrivate[i];
          }
        }
      }
#endif
      SEH_INJECT_FAULT;
      if( iFrame<=iLast ) break;
    }

    SEH_FREE_ON_ERROR(aFrame, 0);
    sqlite3_free(aFrame);
  }

finished:
  if( rc==SQLITE_OK ){
    volatile WalCkptInfo *pInfo;
    int i;











    pWal->hdr.aFrameCksum[0] = aFrameCksum[0];







    pWal->hdr.aFrameCksum[1] = aFrameCksum[1];























    walIndexWriteHdr(pWal);

    /* Reset the checkpoint-header. This is safe because this thread is
    ** currently holding locks that exclude all other writers and
    ** checkpointers. Then set the values of read-mark slots 1 through N.
    */
    pInfo = walCkptInfo(pWal);
    pInfo->nBackfill = 0;


    pInfo->nBackfillAttempted = pWal->hdr.mxFrame;
    pInfo->aReadMark[0] = 0;
    for(i=1; i<WAL_NREADER; i++){
      rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
      if( rc==SQLITE_OK ){
        if( i==1 && pWal->hdr.mxFrame ){
          pInfo->aReadMark[i] = pWal->hdr.mxFrame;
        }else{
          pInfo->aReadMark[i] = READMARK_NOT_USED;
        }
        SEH_INJECT_FAULT;
        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
      }else if( rc!=SQLITE_BUSY ){
        goto recovery_error;

      }
    }

    /* If more than one frame was recovered from the log file, report an
    ** event via sqlite3_log(). This is to help with identifying performance
    ** problems caused by applications routinely shutting down without
    ** checkpointing the log file.
    */
    if( pWal->hdr.nPage ){

      sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,






          "recovered %d frames from WAL file %s",
          pWal->hdr.mxFrame, pWal->zWalName
      );

    }
  }

recovery_error:
  WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
  walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
  return rc;
}

/*
** Close an open wal-index.
*/
static void walIndexClose(Wal *pWal, int isDelete){
  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE || pWal->bShmUnreliable ){
    int i;
    for(i=0; i<pWal->nWiData; i++){
      sqlite3_free((void *)pWal->apWiData[i]);
      pWal->apWiData[i] = 0;
    }
  }
  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
    sqlite3OsShmUnmap(pWal->pDbFd, isDelete);
  }


}

/*
** Open a connection to the WAL file zWalName. The database file must
** already be opened on connection pDbFd. The buffer that zWalName points
** to must remain valid for the lifetime of the returned Wal* handle.
**







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    }
#endif /* SQLITE_ENABLE_EXPENSIVE_ASSERT */
  }

  return rc;
}

/*
** Recover a single wal file - *-wal if iWal==0, or *-wal2 if iWal==1.
*/
static int walIndexRecoverOne(Wal *pWal, int iWal, u32 *pnCkpt, int *pbZero){
  i64 nSize;                      /* Size of log file */
  u32 aFrameCksum[2] = {0, 0};
  int rc;
  sqlite3_file *pWalFd = pWal->apWalFd[iWal];

  assert( iWal==0 || iWal==1 );

  memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
  sqlite3_randomness(8, pWal->hdr.aSalt);

  rc = sqlite3OsFileSize(pWalFd, &nSize);
  if( rc==SQLITE_OK ){
    if( nSize>WAL_HDRSIZE ){
      u8 aBuf[WAL_HDRSIZE];         /* Buffer to load WAL header into */
      u32 *aPrivate = 0;            /* Heap copy of *-shm pg being populated */
      u8 *aFrame = 0;               /* Malloc'd buffer to load entire frame */
      int szFrame;                  /* Number of bytes in buffer aFrame[] */
      u8 *aData;                    /* Pointer to data part of aFrame buffer */
      int szPage;                   /* Page size according to the log */
      u32 magic;                    /* Magic value read from WAL header */
      u32 version;                  /* Magic value read from WAL header */
      int isValid;                  /* True if this frame is valid */
      int iPg;                      /* Current 32KB wal-index page */
      int iLastFrame;               /* Last frame in wal, based on size alone */
      int iLastPg;                  /* Last shm page used by this wal */
  
      /* Read in the WAL header. */
      rc = sqlite3OsRead(pWalFd, aBuf, WAL_HDRSIZE, 0);
      if( rc!=SQLITE_OK ){
        return rc;
      }
  
      /* If the database page size is not a power of two, or is greater than
      ** SQLITE_MAX_PAGE_SIZE, conclude that the WAL file contains no valid 
      ** data. Similarly, if the 'magic' value is invalid, ignore the whole
      ** WAL file.
      */
      magic = sqlite3Get4byte(&aBuf[0]);
      szPage = sqlite3Get4byte(&aBuf[8]);
      if( (magic&0xFFFFFFFE)!=WAL_MAGIC 
       || szPage&(szPage-1) 
       || szPage>SQLITE_MAX_PAGE_SIZE 
       || szPage<512 
      ){
        return SQLITE_OK;
      }
      pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
      pWal->szPage = szPage;
  
      /* Verify that the WAL header checksum is correct */
      walChecksumBytes(pWal->hdr.bigEndCksum==SQLITE_BIGENDIAN, 
          aBuf, WAL_HDRSIZE-2*4, 0, pWal->hdr.aFrameCksum
      );
      if( pWal->hdr.aFrameCksum[0]!=sqlite3Get4byte(&aBuf[24])
       || pWal->hdr.aFrameCksum[1]!=sqlite3Get4byte(&aBuf[28])
      ){
        return SQLITE_OK;
      }
  
      memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);
      *pnCkpt = sqlite3Get4byte(&aBuf[12]);
  
      /* Verify that the version number on the WAL format is one that
      ** are able to understand */
      version = sqlite3Get4byte(&aBuf[4]);
      if( version!=WAL_VERSION1 && version!=WAL_VERSION2 ){
        return SQLITE_CANTOPEN_BKPT;
      }
      pWal->hdr.iVersion = version;
  
      /* Malloc a buffer to read frames into. */
      szFrame = szPage + WAL_FRAME_HDRSIZE;
      aFrame = (u8 *)sqlite3_malloc64(szFrame + WALINDEX_PGSZ);
      SEH_FREE_ON_ERROR(0, aFrame);
      if( !aFrame ){
        return SQLITE_NOMEM_BKPT;
      }
      aData = &aFrame[WAL_FRAME_HDRSIZE];
      aPrivate = (u32*)&aData[szPage];
  
      /* Read all frames from the log file. */
      iLastFrame = (nSize - WAL_HDRSIZE) / szFrame;
      if( version==WAL_VERSION2 ){
        iLastPg = walFramePage2(iWal, iLastFrame);
      }else{
        iLastPg = walFramePage(iLastFrame);
      }
      for(iPg=iWal; iPg<=iLastPg; iPg+=(version==WAL_VERSION2 ? 2 : 1)){
        u32 *aShare;
        int iFrame;                 /* Index of last frame read */
        int iLast;
        int iFirst;
        int nHdr, nHdr32;

        rc = walIndexPage(pWal, iPg, (volatile u32**)&aShare);
        assert( aShare!=0 || rc!=SQLITE_OK );
        if( aShare==0 ) break;
        SEH_SET_ON_ERROR(iPg, aShare);
        pWal->apWiData[iPg] = aPrivate;

        if( iWal ){
          assert( version==WAL_VERSION2 );
          iFirst = 1 + (iPg/2)*HASHTABLE_NPAGE;
          iLast = iFirst + HASHTABLE_NPAGE - 1;
        }else{
          int i2 = (version==WAL_VERSION2) ? (iPg/2) : iPg;
          iLast = HASHTABLE_NPAGE_ONE+i2*HASHTABLE_NPAGE;
          iFirst = 1 + (i2==0?0:HASHTABLE_NPAGE_ONE+(i2-1)*HASHTABLE_NPAGE);
        }
        iLast = MIN(iLast, iLastFrame);

        for(iFrame=iFirst; iFrame<=iLast; iFrame++){
          i64 iOffset = walFrameOffset(iFrame, szPage);
          u32 pgno;                 /* Database page number for frame */
          u32 nTruncate;            /* dbsize field from frame header */

          /* Read and decode the next log frame. */
          rc = sqlite3OsRead(pWalFd, aFrame, szFrame, iOffset);
          if( rc!=SQLITE_OK ) break;
          isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
          if( !isValid ) break;
          rc = walIndexAppend(pWal, iWal, iFrame, pgno);
          if( NEVER(rc!=SQLITE_OK) ) break;
  
          /* If nTruncate is non-zero, this is a commit record. */
          if( nTruncate ){
            pWal->hdr.mxFrame = iFrame;
            pWal->hdr.nPage = nTruncate;
            pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
            testcase( szPage<=32768 );
            testcase( szPage>=65536 );
            aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
            aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
          }
        }
        pWal->apWiData[iPg] = aShare;
        SEH_SET_ON_ERROR(0, 0);
        nHdr = (iPg==0 ? WALINDEX_HDR_SIZE : 0);
        nHdr32 = nHdr / sizeof(u32);
#ifndef SQLITE_SAFER_WALINDEX_RECOVERY
        /* Memcpy() should work fine here, on all reasonable implementations.
        ** Technically, memcpy() might change the destination to some
        ** intermediate value before setting to the final value, and that might
        ** cause a concurrent reader to malfunction.  Memcpy() is allowed to
        ** do that, according to the spec, but no memcpy() implementation that
        ** we know of actually does that, which is why we say that memcpy()
        ** is safe for this.  Memcpy() is certainly a lot faster.
        */
        memcpy(&aShare[nHdr32], &aPrivate[nHdr32], WALINDEX_PGSZ-nHdr);
#else
        /* In the event that some platform is found for which memcpy()
        ** changes the destination to some intermediate value before
        ** setting the final value, this alternative copy routine is
        ** provided.
        */
        {
          int i;
          for(i=nHdr32; i<WALINDEX_PGSZ/sizeof(u32); i++){
            if( aShare[i]!=aPrivate[i] ){
              /* Atomic memory operations are not required here because if
              ** the value needs to be changed, that means it is not being
              ** accessed concurrently. */
              aShare[i] = aPrivate[i];
            }
          }
        }
#endif
        SEH_INJECT_FAULT;
        if( iFrame<=iLast ) break;
      }
  
      SEH_FREE_ON_ERROR(aFrame, 0);
      sqlite3_free(aFrame);
    }else if( pbZero ){
      *pbZero = 1;
    }
  }

  pWal->hdr.aFrameCksum[0] = aFrameCksum[0];
  pWal->hdr.aFrameCksum[1] = aFrameCksum[1];

  return rc;
}

static int walOpenWal2(Wal *pWal){
  int rc = SQLITE_OK;
  if( !isOpen(pWal->apWalFd[1]) ){
    int f = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
    rc = sqlite3OsOpen(pWal->pVfs, pWal->zWalName2, pWal->apWalFd[1], f, &f);
  }
  return rc;
}

static int walTruncateWal2(Wal *pWal){
  int bIs;
  int rc;
  assert( !isOpen(pWal->apWalFd[1]) );
  rc = sqlite3OsAccess(pWal->pVfs, pWal->zWalName2, SQLITE_ACCESS_EXISTS, &bIs);
  if( rc==SQLITE_OK && bIs ){
    rc = walOpenWal2(pWal);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsTruncate(pWal->apWalFd[1], 0);
      sqlite3OsClose(pWal->apWalFd[1]);
    }
  }
  return rc;
}

/*
** Recover the wal-index by reading the write-ahead log file.
**
** This routine first tries to establish an exclusive lock on the
** wal-index to prevent other threads/processes from doing anything
** with the WAL or wal-index while recovery is running.  The
** WAL_RECOVER_LOCK is also held so that other threads will know
** that this thread is running recovery.  If unable to establish
** the necessary locks, this routine returns SQLITE_BUSY.
*/
static int walIndexRecover(Wal *pWal){
  int rc;                         /* Return Code */


  int iLock;                      /* Lock offset to lock for checkpoint */
  u32 nCkpt1 = 0xFFFFFFFF;
  u32 nCkpt2 = 0xFFFFFFFF;
  int bZero = 0;
  WalIndexHdr hdr;

  /* Obtain an exclusive lock on all byte in the locking range not already
  ** locked by the caller. The caller is guaranteed to have locked the
  ** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte.
  ** If successful, the same bytes that are locked here are unlocked before
  ** this function returns.
  */
  assert( pWal->ckptLock==1 || pWal->ckptLock==0 );
  assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 );
  assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE );
  assert( pWal->writeLock );
  iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock;
  rc = walLockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
  if( rc ){
    return rc;
  }

  WALTRACE(("WAL%p: recovery begin...\n", pWal));

  /* Recover the *-wal file. If a valid version-1 header is recovered
  ** from it, do not open the *-wal2 file. Even if it exists.




  **












  ** Otherwise, if the *-wal2 file exists or if the "wal2" flag was 



  ** specified when sqlite3WalOpen() was called, open and recover

  ** the *-wal2 file. Except, if the *-wal file was zero bytes in size,



  ** truncate the *-wal2 to zero bytes in size.
  **







  ** After this block has run, if the *-wal2 file is open the system
  ** starts up in VERSION2 mode. In this case pWal->hdr contains the 
  ** wal-index header considering only *-wal2. Stack variable hdr





  ** contains the wal-index header considering only *-wal. The hash 









  ** tables are populated for both.  

  **

  ** Or, if the *-wal2 file is not open, start up in VERSION1 mode.



  ** pWal->hdr is already populated.






  */
  rc = walIndexRecoverOne(pWal, 0, &nCkpt1, &bZero);



  assert( pWal->hdr.iVersion==0 

      || pWal->hdr.iVersion==WAL_VERSION1 
      || pWal->hdr.iVersion==WAL_VERSION2 






  );
  if( rc==SQLITE_OK && bZero ){


    rc = walTruncateWal2(pWal);
  }




  if( rc==SQLITE_OK && pWal->hdr.iVersion!=WAL_VERSION1 ){
    int bOpen = 1;
    sqlite3_vfs *pVfs = pWal->pVfs;
    if( pWal->hdr.iVersion==0 && pWal->bWal2==0 ){
      rc = sqlite3OsAccess(pVfs, pWal->zWalName2, SQLITE_ACCESS_EXISTS, &bOpen);
    }

    if( rc==SQLITE_OK && bOpen ){
      rc = walOpenWal2(pWal);
      if( rc==SQLITE_OK ){

        hdr = pWal->hdr;
        rc = walIndexRecoverOne(pWal, 1, &nCkpt2, 0);

      }









    }
  }









































  if( rc==SQLITE_OK ){
    volatile WalCkptInfo *pInfo;

    if( isOpen(pWal->apWalFd[1]) ){
      /* The case where *-wal2 may follow *-wal */
      if( nCkpt2<=0x0F && nCkpt2==nCkpt1+1 ){
        if( pWal->hdr.mxFrame
         && sqlite3Get4byte((u8*)(&pWal->hdr.aSalt[0]))==hdr.aFrameCksum[0]
         && sqlite3Get4byte((u8*)(&pWal->hdr.aSalt[1]))==hdr.aFrameCksum[1]
        ){
          walidxSetFile(&pWal->hdr, 1);
          walidxSetMxFrame(&pWal->hdr, 1, pWal->hdr.mxFrame);
          walidxSetMxFrame(&pWal->hdr, 0, hdr.mxFrame);
        }else{
          pWal->hdr = hdr;
        }
      }else

      /* When *-wal may follow *-wal2 */
      if( (nCkpt2==0x0F && nCkpt1==0) || (nCkpt2<0x0F && nCkpt2==nCkpt1-1) ){
        if( hdr.mxFrame
         && sqlite3Get4byte((u8*)(&hdr.aSalt[0]))==pWal->hdr.aFrameCksum[0]
         && sqlite3Get4byte((u8*)(&hdr.aSalt[1]))==pWal->hdr.aFrameCksum[1]
        ){
          SWAP(WalIndexHdr, pWal->hdr, hdr);
          walidxSetMxFrame(&pWal->hdr, 1, hdr.mxFrame);
        }else{
          walidxSetFile(&pWal->hdr, 1);
          walidxSetMxFrame(&pWal->hdr, 1, pWal->hdr.mxFrame);
          walidxSetMxFrame(&pWal->hdr, 0, 0);
        }
      }else

      /* Fallback */
      if( nCkpt1<=nCkpt2 ){
        pWal->hdr = hdr;
      }else{
        walidxSetFile(&pWal->hdr, 1);
        walidxSetMxFrame(&pWal->hdr, 1, pWal->hdr.mxFrame);
        walidxSetMxFrame(&pWal->hdr, 0, 0);
      }
      pWal->hdr.iVersion = WAL_VERSION2;
    }else{
      pWal->hdr.iVersion = WAL_VERSION1;
    }

    walIndexWriteHdr(pWal);

    /* Reset the checkpoint-header. This is safe because this thread is
    ** currently holding locks that exclude all other writers and
    ** checkpointers. Then set the values of read-mark slots 1 through N.
    */
    pInfo = walCkptInfo(pWal);
    memset((void*)pInfo, 0, sizeof(WalCkptInfo));
    if( 0==isWalMode2(pWal) ){
      int i;
      pInfo->nBackfillAttempted = pWal->hdr.mxFrame;
      pInfo->aReadMark[0] = 0;
      for(i=1; i<WAL_NREADER; i++){
        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
        if( rc==SQLITE_OK ){
          if( i==1 && pWal->hdr.mxFrame ){
            pInfo->aReadMark[i] = pWal->hdr.mxFrame;
          }else{
            pInfo->aReadMark[i] = READMARK_NOT_USED;
          }

          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
        }else if( rc!=SQLITE_BUSY ){
          break;
        }
      }
    }

    /* If more than one frame was recovered from the log file, report an
    ** event via sqlite3_log(). This is to help with identifying performance
    ** problems caused by applications routinely shutting down without
    ** checkpointing the log file.  */

    if( pWal->hdr.nPage ){
      if( isWalMode2(pWal) ){
        sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,
            "recovered (%d,%d) frames from WAL files %s[2] (wal2 mode)",
            walidxGetMxFrame(&pWal->hdr, 0), walidxGetMxFrame(&pWal->hdr, 1), 
            pWal->zWalName
        );
      }else{
        sqlite3_log(SQLITE_NOTICE_RECOVER_WAL,
            "recovered %d frames from WAL file %s",
            pWal->hdr.mxFrame, pWal->zWalName
        );
      }
    }
  }


  WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok"));
  walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock);
  return rc;
}

/*
** Close an open wal-index and wal files.
*/
static void walIndexClose(Wal *pWal, int isDelete){
  if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE || pWal->bShmUnreliable ){
    int i;
    for(i=0; i<pWal->nWiData; i++){
      sqlite3_free((void *)pWal->apWiData[i]);
      pWal->apWiData[i] = 0;
    }
  }
  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
    sqlite3OsShmUnmap(pWal->pDbFd, isDelete);
  }
  sqlite3OsClose(pWal->apWalFd[0]);
  sqlite3OsClose(pWal->apWalFd[1]);
}

/*
** Open a connection to the WAL file zWalName. The database file must
** already be opened on connection pDbFd. The buffer that zWalName points
** to must remain valid for the lifetime of the returned Wal* handle.
**
1632
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*/
int sqlite3WalOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
  sqlite3_file *pDbFd,            /* The open database file */
  const char *zWalName,           /* Name of the WAL file */
  int bNoShm,                     /* True to run in heap-memory mode */
  i64 mxWalSize,                  /* Truncate WAL to this size on reset */

  Wal **ppWal                     /* OUT: Allocated Wal handle */
){
  int rc;                         /* Return Code */
  Wal *pRet;                      /* Object to allocate and return */
  int flags;                      /* Flags passed to OsOpen() */


  assert( zWalName && zWalName[0] );
  assert( pDbFd );

  /* Verify the values of various constants.  Any changes to the values
  ** of these constants would result in an incompatible on-disk format
  ** for the -shm file.  Any change that causes one of these asserts to







>





>







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*/
int sqlite3WalOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
  sqlite3_file *pDbFd,            /* The open database file */
  const char *zWalName,           /* Name of the WAL file */
  int bNoShm,                     /* True to run in heap-memory mode */
  i64 mxWalSize,                  /* Truncate WAL to this size on reset */
  int bWal2,                      /* True to open in wal2 mode */
  Wal **ppWal                     /* OUT: Allocated Wal handle */
){
  int rc;                         /* Return Code */
  Wal *pRet;                      /* Object to allocate and return */
  int flags;                      /* Flags passed to OsOpen() */
  int nByte;                      /* Bytes of space to allocate */

  assert( zWalName && zWalName[0] );
  assert( pDbFd );

  /* Verify the values of various constants.  Any changes to the values
  ** of these constants would result in an incompatible on-disk format
  ** for the -shm file.  Any change that causes one of these asserts to
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#ifdef WIN_SHM_BASE
  assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET );
#endif
#ifdef UNIX_SHM_BASE
  assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET );
#endif



  /* Allocate an instance of struct Wal to return. */
  *ppWal = 0;
  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile);
  if( !pRet ){
    return SQLITE_NOMEM_BKPT;
  }

  pRet->pVfs = pVfs;
  pRet->pWalFd = (sqlite3_file *)&pRet[1];

  pRet->pDbFd = pDbFd;
  pRet->readLock = -1;
  pRet->mxWalSize = mxWalSize;
  pRet->zWalName = zWalName;
  pRet->syncHeader = 1;
  pRet->padToSectorBoundary = 1;
  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);



  /* Open file handle on the write-ahead log file. */
  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
    pRet->readOnly = WAL_RDONLY;
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);
    sqlite3OsClose(pRet->pWalFd);
    sqlite3_free(pRet);
  }else{
    int iDC = sqlite3OsDeviceCharacteristics(pDbFd);
    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
      pRet->padToSectorBoundary = 0;
    }







>



|





|
>

|





>
>

|

|






<







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#ifdef WIN_SHM_BASE
  assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET );
#endif
#ifdef UNIX_SHM_BASE
  assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET );
#endif

  nByte = sizeof(Wal) + pVfs->szOsFile*2;

  /* Allocate an instance of struct Wal to return. */
  *ppWal = 0;
  pRet = (Wal*)sqlite3MallocZero(nByte);
  if( !pRet ){
    return SQLITE_NOMEM_BKPT;
  }

  pRet->pVfs = pVfs;
  pRet->apWalFd[0] = (sqlite3_file*)((char*)pRet+sizeof(Wal));
  pRet->apWalFd[1] = (sqlite3_file*)((char*)pRet+sizeof(Wal)+pVfs->szOsFile);
  pRet->pDbFd = pDbFd;
  pRet->readLock = WAL_LOCK_NONE;
  pRet->mxWalSize = mxWalSize;
  pRet->zWalName = zWalName;
  pRet->syncHeader = 1;
  pRet->padToSectorBoundary = 1;
  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);
  pRet->bWal2 = bWal2;
  pRet->zWalName2 = &zWalName[sqlite3Strlen30(zWalName)+1];

  /* Open a file handle on the first write-ahead log file. */
  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
  rc = sqlite3OsOpen(pVfs, zWalName, pRet->apWalFd[0], flags, &flags);
  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
    pRet->readOnly = WAL_RDONLY;
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);

    sqlite3_free(pRet);
  }else{
    int iDC = sqlite3OsDeviceCharacteristics(pDbFd);
    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
      pRet->padToSectorBoundary = 0;
    }
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940





1941
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1943
1944
1945

1946
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1948
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1950
1951

1952
1953




1954


1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
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1968
1969
1970

1971
1972
1973
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1977

1978







1979

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1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
*/
static void walIteratorFree(WalIterator *p){
  sqlite3_free(p);
}

/*
** Construct a WalInterator object that can be used to loop over all
** pages in the WAL following frame nBackfill in ascending order. Frames
** nBackfill or earlier may be included - excluding them is an optimization
** only. The caller must hold the checkpoint lock.
**
** On success, make *pp point to the newly allocated WalInterator object
** return SQLITE_OK. Otherwise, return an error code. If this routine
** returns an error, the value of *pp is undefined.
**
** The calling routine should invoke walIteratorFree() to destroy the
** WalIterator object when it has finished with it.
*/
static int walIteratorInit(Wal *pWal, u32 nBackfill, WalIterator **pp){





  WalIterator *p;                 /* Return value */
  int nSegment;                   /* Number of segments to merge */
  u32 iLast;                      /* Last frame in log */
  sqlite3_int64 nByte;            /* Number of bytes to allocate */
  int i;                          /* Iterator variable */

  ht_slot *aTmp;                  /* Temp space used by merge-sort */
  int rc = SQLITE_OK;             /* Return Code */





  /* This routine only runs while holding the checkpoint lock. And
  ** it only runs if there is actually content in the log (mxFrame>0).
  */

  assert( pWal->ckptLock && pWal->hdr.mxFrame>0 );
  iLast = pWal->hdr.mxFrame;







  /* Allocate space for the WalIterator object. */
  nSegment = walFramePage(iLast) + 1;
  nByte = sizeof(WalIterator)
        + (nSegment-1)*sizeof(struct WalSegment)
        + iLast*sizeof(ht_slot);
  p = (WalIterator *)sqlite3_malloc64(nByte
      + sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
  );
  if( !p ){
    return SQLITE_NOMEM_BKPT;
  }
  memset(p, 0, nByte);
  p->nSegment = nSegment;
  aTmp = (ht_slot*)&(((u8*)p)[nByte]);
  SEH_FREE_ON_ERROR(0, p);
  for(i=walFramePage(nBackfill+1); rc==SQLITE_OK && i<nSegment; i++){

    WalHashLoc sLoc;

    rc = walHashGet(pWal, i, &sLoc);
    if( rc==SQLITE_OK ){
      int j;                      /* Counter variable */
      int nEntry;                 /* Number of entries in this segment */
      ht_slot *aIndex;            /* Sorted index for this segment */









      if( (i+1)==nSegment ){

        nEntry = (int)(iLast - sLoc.iZero);
      }else{
        nEntry = (int)((u32*)sLoc.aHash - (u32*)sLoc.aPgno);
      }
      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[sLoc.iZero];
      sLoc.iZero++;

      for(j=0; j<nEntry; j++){
        aIndex[j] = (ht_slot)j;
      }
      walMergesort((u32 *)sLoc.aPgno, aTmp, aIndex, &nEntry);
      p->aSegment[i].iZero = sLoc.iZero;
      p->aSegment[i].nEntry = nEntry;
      p->aSegment[i].aIndex = aIndex;
      p->aSegment[i].aPgno = (u32 *)sLoc.aPgno;
    }
  }
  if( rc!=SQLITE_OK ){
    SEH_FREE_ON_ERROR(p, 0);
    walIteratorFree(p);
    p = 0;
  }







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2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459

2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
*/
static void walIteratorFree(WalIterator *p){
  sqlite3_free(p);
}

/*
** Construct a WalInterator object that can be used to loop over all
** pages in wal file iWal following frame nBackfill in ascending order. Frames
** nBackfill or earlier may be included - excluding them is an optimization
** only. The caller must hold the checkpoint lock.
**
** On success, make *pp point to the newly allocated WalIterator object
** and return SQLITE_OK. Otherwise, return an error code. If this routine
** returns an error, the final value of *pp is undefined.
**
** The calling routine should invoke walIteratorFree() to destroy the
** WalIterator object when it has finished with it.
*/
static int walIteratorInit(
  Wal *pWal, 
  int iWal, 
  u32 nBackfill, 
  WalIterator **pp
){
  WalIterator *p;                 /* Return value */
  int nSegment;                   /* Number of segments to merge */
  u32 iLast;                      /* Last frame in log */
  sqlite3_int64 nByte;            /* Number of bytes to allocate */
  int i;                          /* Iterator variable */
  int iLastSeg;                   /* Last hash table to iterate though */
  ht_slot *aTmp;                  /* Temp space used by merge-sort */
  int rc = SQLITE_OK;             /* Return Code */
  int iMode = isWalMode2(pWal) ? 2 : 1;

  assert( isWalMode2(pWal) || iWal==0 );
  assert( 0==isWalMode2(pWal) || nBackfill==0 );

  /* This routine only runs while holding the checkpoint lock. And
  ** it only runs if there is actually content in the log (mxFrame>0).
  */
  iLast = walidxGetMxFrame(&pWal->hdr, iWal);
  assert( pWal->ckptLock && iLast>0 );

  if( iMode==2 ){
    iLastSeg = walFramePage2(iWal, iLast);
  }else{
    iLastSeg = walFramePage(iLast);
  }
  nSegment = 1 + (iLastSeg/iMode);

  /* Allocate space for the WalIterator object. */

  nByte = sizeof(WalIterator)
        + (nSegment-1)*sizeof(struct WalSegment)
        + iLast*sizeof(ht_slot);
  p = (WalIterator *)sqlite3_malloc64(nByte
      + sizeof(ht_slot) * (iLast>HASHTABLE_NPAGE?HASHTABLE_NPAGE:iLast)
  );
  if( !p ){
    return SQLITE_NOMEM_BKPT;
  }
  memset(p, 0, nByte);
  p->nSegment = nSegment;
  aTmp = (ht_slot*)&(((u8*)p)[nByte]);
  SEH_FREE_ON_ERROR(0, p);
  i = iMode==2 ? iWal : walFramePage(nBackfill+1);
  for(; rc==SQLITE_OK && i<=iLastSeg; i+=iMode){
    WalHashLoc sLoc;

    rc = walHashGet(pWal, i, &sLoc);
    if( rc==SQLITE_OK ){
      int j;                      /* Counter variable */
      int nEntry;                 /* Number of entries in this segment */
      ht_slot *aIndex;            /* Sorted index for this segment */
      u32 iZero;

      if( iMode==2 ){
        walExternalDecode(sLoc.iZero+1, &iZero);
        iZero--;
        assert( iZero==0 || i>=2 );
      }else{
        iZero = sLoc.iZero;
      }

      if( i==iLastSeg ){
        nEntry = (int)(iLast - iZero);
      }else{
        nEntry = (int)((u32*)sLoc.aHash - (u32*)sLoc.aPgno);
      }
      aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[iZero];
      iZero++;

      for(j=0; j<nEntry; j++){
        aIndex[j] = (ht_slot)j;
      }
      walMergesort((u32*)sLoc.aPgno, aTmp, aIndex, &nEntry);
      p->aSegment[i/iMode].iZero = iZero;
      p->aSegment[i/iMode].nEntry = nEntry;
      p->aSegment[i/iMode].aIndex = aIndex;
      p->aSegment[i/iMode].aPgno = (u32*)sLoc.aPgno;
    }
  }
  if( rc!=SQLITE_OK ){
    SEH_FREE_ON_ERROR(p, 0);
    walIteratorFree(p);
    p = 0;
  }
2136
2137
2138
2139
2140
2141
2142

2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153






























































2154
2155
2156
2157
2158
2159
2160
** new wal-index header. It should be passed a pseudo-random value (i.e.
** one obtained from sqlite3_randomness()).
*/
static void walRestartHdr(Wal *pWal, u32 salt1){
  volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
  int i;                          /* Loop counter */
  u32 *aSalt = pWal->hdr.aSalt;   /* Big-endian salt values */

  pWal->nCkpt++;
  pWal->hdr.mxFrame = 0;
  sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
  memcpy(&pWal->hdr.aSalt[1], &salt1, 4);
  walIndexWriteHdr(pWal);
  AtomicStore(&pInfo->nBackfill, 0);
  pInfo->nBackfillAttempted = 0;
  pInfo->aReadMark[1] = 0;
  for(i=2; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
  assert( pInfo->aReadMark[0]==0 );
}































































/*
** Copy as much content as we can from the WAL back into the database file
** in response to an sqlite3_wal_checkpoint() request or the equivalent.
**
** The amount of information copies from WAL to database might be limited
** by active readers.  This routine will never overwrite a database page







>











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2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
** new wal-index header. It should be passed a pseudo-random value (i.e.
** one obtained from sqlite3_randomness()).
*/
static void walRestartHdr(Wal *pWal, u32 salt1){
  volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
  int i;                          /* Loop counter */
  u32 *aSalt = pWal->hdr.aSalt;   /* Big-endian salt values */
  assert( isWalMode2(pWal)==0 );
  pWal->nCkpt++;
  pWal->hdr.mxFrame = 0;
  sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
  memcpy(&pWal->hdr.aSalt[1], &salt1, 4);
  walIndexWriteHdr(pWal);
  AtomicStore(&pInfo->nBackfill, 0);
  pInfo->nBackfillAttempted = 0;
  pInfo->aReadMark[1] = 0;
  for(i=2; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
  assert( pInfo->aReadMark[0]==0 );
}

/*
** This function is used in wal2 mode.
**
** This function is called when writer pWal is just about to start 
** writing out frames. Parameter iApp is the current wal file. The "other" wal
** file (wal file !iApp) has been fully checkpointed. This function returns
** SQLITE_OK if there are no readers preventing the writer from switching to
** the other wal file. Or SQLITE_BUSY if there are.
*/
static int wal2RestartOk(Wal *pWal, int iApp){
  /* The other wal file (wal file !iApp) can be overwritten if there
  ** are no readers reading from it - no "full" or "partial" locks.
  ** Technically speaking it is not possible for any reader to hold
  ** a "part" lock, as this would have prevented the file from being
  ** checkpointed. But checking anyway doesn't hurt. The following
  ** is equivalent to:
  **
  **   if( iApp==0 ) eLock = WAL_LOCK_PART1_FULL2;
  **   if( iApp==1 ) eLock = WAL_LOCK_PART1;
  */
  int eLock = 1 + (iApp==0);

  assert( WAL_LOCK_PART1==1 );
  assert( WAL_LOCK_PART1_FULL2==2 );
  assert( WAL_LOCK_PART2_FULL1==3 );
  assert( WAL_LOCK_PART2==4 );

  assert( iApp!=0 || eLock==WAL_LOCK_PART1_FULL2 );
  assert( iApp!=1 || eLock==WAL_LOCK_PART1 );

  return walLockExclusive(pWal, WAL_READ_LOCK(eLock), 3);
}
static void wal2RestartFinished(Wal *pWal, int iApp){
  walUnlockExclusive(pWal, WAL_READ_LOCK(1 + (iApp==0)), 3);
}

/*
** This function is used in wal2 mode.
**
** This function is called when a checkpointer wishes to checkpoint wal
** file iCkpt. It takes the required lock and, if successful, returns
** SQLITE_OK. Otherwise, an SQLite error code (e.g. SQLITE_BUSY). If this
** function returns SQLITE_OK, it is the responsibility of the caller
** to invoke wal2CheckpointFinished() to release the lock.
*/
static int wal2CheckpointOk(Wal *pWal, int iCkpt){
  int eLock = 1 + (iCkpt*2);

  assert( WAL_LOCK_PART1==1 );
  assert( WAL_LOCK_PART1_FULL2==2 );
  assert( WAL_LOCK_PART2_FULL1==3 );
  assert( WAL_LOCK_PART2==4 );

  assert( iCkpt!=0 || eLock==WAL_LOCK_PART1 );
  assert( iCkpt!=1 || eLock==WAL_LOCK_PART2_FULL1 );

  return walLockExclusive(pWal, WAL_READ_LOCK(eLock), 2);
}
static void wal2CheckpointFinished(Wal *pWal, int iCkpt){
  walUnlockExclusive(pWal, WAL_READ_LOCK(1 + (iCkpt*2)), 2);
}

/*
** Copy as much content as we can from the WAL back into the database file
** in response to an sqlite3_wal_checkpoint() request or the equivalent.
**
** The amount of information copies from WAL to database might be limited
** by active readers.  This routine will never overwrite a database page
2197
2198
2199
2200
2201
2202
2203


2204

2205
2206
2207
2208

2209











2210
2211
2212
2213
2214
2215
2216
2217
2218
2219

2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235

2236
2237
2238
2239
2240
2241

2242
2243
2244
2245
2246
2247
2248
2249


2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263

2264
2265
2266
2267
2268

2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279

2280


2281
2282
2283
2284
2285
2286

2287
2288
2289



2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300

2301
2302
2303
2304
2305

2306
2307
2308
2309
2310
2311
2312

2313
2314
2315

2316

2317
2318
2319
2320
2321
2322
2323

2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
  WalIterator *pIter = 0;         /* Wal iterator context */
  u32 iDbpage = 0;                /* Next database page to write */
  u32 iFrame = 0;                 /* Wal frame containing data for iDbpage */
  u32 mxSafeFrame;                /* Max frame that can be backfilled */
  u32 mxPage;                     /* Max database page to write */
  int i;                          /* Loop counter */
  volatile WalCkptInfo *pInfo;    /* The checkpoint status information */




  szPage = walPagesize(pWal);
  testcase( szPage<=32768 );
  testcase( szPage>=65536 );
  pInfo = walCkptInfo(pWal);

  if( pInfo->nBackfill<pWal->hdr.mxFrame ){












    /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
    ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
    assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );

    /* Compute in mxSafeFrame the index of the last frame of the WAL that is
    ** safe to write into the database.  Frames beyond mxSafeFrame might
    ** overwrite database pages that are in use by active readers and thus
    ** cannot be backfilled from the WAL.
    */

    mxSafeFrame = pWal->hdr.mxFrame;
    mxPage = pWal->hdr.nPage;
    for(i=1; i<WAL_NREADER; i++){
      u32 y = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
      if( mxSafeFrame>y ){
        assert( y<=pWal->hdr.mxFrame );
        rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
        if( rc==SQLITE_OK ){
          u32 iMark = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
          AtomicStore(pInfo->aReadMark+i, iMark); SEH_INJECT_FAULT;
          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
        }else if( rc==SQLITE_BUSY ){
          mxSafeFrame = y;
          xBusy = 0;
        }else{
          goto walcheckpoint_out;

        }
      }
    }

    /* Allocate the iterator */
    if( pInfo->nBackfill<mxSafeFrame ){

      rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
      assert( rc==SQLITE_OK || pIter==0 );
    }

    if( pIter
     && (rc = walBusyLock(pWal,xBusy,pBusyArg,WAL_READ_LOCK(0),1))==SQLITE_OK
    ){
      u32 nBackfill = pInfo->nBackfill;


      pInfo->nBackfillAttempted = mxSafeFrame; SEH_INJECT_FAULT;

      /* Sync the WAL to disk */
      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));

      /* If the database may grow as a result of this checkpoint, hint
      ** about the eventual size of the db file to the VFS layer.
      */
      if( rc==SQLITE_OK ){
        i64 nReq = ((i64)mxPage * szPage);
        i64 nSize;                    /* Current size of database file */
        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_START, 0);
        rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
        if( rc==SQLITE_OK && nSize<nReq ){

          if( (nSize+65536+(i64)pWal->hdr.mxFrame*szPage)<nReq ){
            /* If the size of the final database is larger than the current
            ** database plus the amount of data in the wal file, plus the
            ** maximum size of the pending-byte page (65536 bytes), then
            ** must be corruption somewhere.  */

            rc = SQLITE_CORRUPT_BKPT;
          }else{
            sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT,&nReq);
          }
        }

      }

      /* Iterate through the contents of the WAL, copying data to the db file */
      while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
        i64 iOffset;

        assert( walFramePgno(pWal, iFrame)==iDbpage );


        SEH_INJECT_FAULT;
        if( AtomicLoad(&db->u1.isInterrupted) ){
          rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_INTERRUPT;
          break;
        }
        if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ){

          continue;
        }
        iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;



        /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
        rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
        if( rc!=SQLITE_OK ) break;
        iOffset = (iDbpage-1)*(i64)szPage;
        testcase( IS_BIG_INT(iOffset) );
        rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
        if( rc!=SQLITE_OK ) break;
      }
      sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_DONE, 0);

      /* If work was actually accomplished... */

      if( rc==SQLITE_OK ){
        if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
          i64 szDb = pWal->hdr.nPage*(i64)szPage;
          testcase( IS_BIG_INT(szDb) );
          rc = sqlite3OsTruncate(pWal->pDbFd, szDb);

          if( rc==SQLITE_OK ){
            rc = sqlite3OsSync(pWal->pDbFd, CKPT_SYNC_FLAGS(sync_flags));
          }
        }
        if( rc==SQLITE_OK ){
          AtomicStore(&pInfo->nBackfill, mxSafeFrame); SEH_INJECT_FAULT;
        }

      }

      /* Release the reader lock held while backfilling */

      walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);

    }

    if( rc==SQLITE_BUSY ){
      /* Reset the return code so as not to report a checkpoint failure
      ** just because there are active readers.  */
      rc = SQLITE_OK;
    }

  }

  /* If this is an SQLITE_CHECKPOINT_RESTART or TRUNCATE operation, and the
  ** entire wal file has been copied into the database file, then block
  ** until all readers have finished using the wal file. This ensures that
  ** the next process to write to the database restarts the wal file.
  */
  if( rc==SQLITE_OK && eMode!=SQLITE_CHECKPOINT_PASSIVE ){
    assert( pWal->writeLock );
    SEH_INJECT_FAULT;
    if( pInfo->nBackfill<pWal->hdr.mxFrame ){
      rc = SQLITE_BUSY;
    }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
      u32 salt1;
      sqlite3_randomness(4, &salt1);







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2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
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2793
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2800
2801
2802
2803
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2807
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2813
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2846
2847
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2849
2850
2851
2852

2853
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2869
2870

2871
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2916

2917
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2938
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2940
2941
2942
2943
2944
2945
2946
  WalIterator *pIter = 0;         /* Wal iterator context */
  u32 iDbpage = 0;                /* Next database page to write */
  u32 iFrame = 0;                 /* Wal frame containing data for iDbpage */
  u32 mxSafeFrame;                /* Max frame that can be backfilled */
  u32 mxPage;                     /* Max database page to write */
  int i;                          /* Loop counter */
  volatile WalCkptInfo *pInfo;    /* The checkpoint status information */
  int bWal2 = isWalMode2(pWal);   /* True for wal2 connections */
  int iCkpt = bWal2 ? !walidxGetFile(&pWal->hdr) : 0;

  mxSafeFrame = walidxGetMxFrame(&pWal->hdr, iCkpt);
  szPage = walPagesize(pWal);
  testcase( szPage<=32768 );
  testcase( szPage>=65536 );
  pInfo = walCkptInfo(pWal);
  if( (bWal2==1 && pInfo->nBackfill==0 && mxSafeFrame) 
   || (bWal2==0 && pInfo->nBackfill<mxSafeFrame)
  ){
    sqlite3_file *pWalFd = pWal->apWalFd[iCkpt];
    mxPage = pWal->hdr.nPage;

    /* If this is a wal2 system, check for a reader holding a lock 
    ** preventing this checkpoint operation. If one is found, return
    ** early.  */
    if( bWal2 ){
      rc = wal2CheckpointOk(pWal, iCkpt);
      if( rc!=SQLITE_OK ) return rc;
    }

    /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
    ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
    assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );

    /* If this is a wal system (not wal2), compute in mxSafeFrame the index 
    ** of the last frame of the WAL that is safe to write into the database.
    ** Frames beyond mxSafeFrame might overwrite database pages that are in 
    ** use by active readers and thus cannot be backfilled from the WAL.
    */
    if( bWal2==0 ){
      mxSafeFrame = pWal->hdr.mxFrame;
      mxPage = pWal->hdr.nPage;
      for(i=1; i<WAL_NREADER; i++){
        u32 y = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
        if( mxSafeFrame>y ){
          assert( y<=pWal->hdr.mxFrame );
          rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
          if( rc==SQLITE_OK ){
            u32 iMark = (i==1 ? mxSafeFrame : READMARK_NOT_USED);
            AtomicStore(pInfo->aReadMark+i, iMark); SEH_INJECT_FAULT;
            walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
          }else if( rc==SQLITE_BUSY ){
            mxSafeFrame = y;
            xBusy = 0;
          }else{
            goto walcheckpoint_out;
          }
        }
      }
    }

    /* Allocate the iterator */
    if( bWal2 || pInfo->nBackfill<mxSafeFrame ){
      assert( bWal2==0 || pInfo->nBackfill==0 );
      rc = walIteratorInit(pWal, iCkpt, pInfo->nBackfill, &pIter);
      assert( rc==SQLITE_OK || pIter==0 );
    }

    if( pIter && (bWal2 
     || (rc = walBusyLock(pWal, xBusy, pBusyArg,WAL_READ_LOCK(0),1))==SQLITE_OK
    )){
      u32 nBackfill = pInfo->nBackfill;

      assert( bWal2==0 || nBackfill==0 );
      pInfo->nBackfillAttempted = mxSafeFrame; SEH_INJECT_FAULT;

      /* Sync the wal file being checkpointed to disk */
      rc = sqlite3OsSync(pWalFd, CKPT_SYNC_FLAGS(sync_flags));

      /* If the database may grow as a result of this checkpoint, hint
      ** about the eventual size of the db file to the VFS layer.  */

      if( rc==SQLITE_OK ){
        i64 nReq = ((i64)mxPage * szPage);
        i64 nSize;                    /* Current size of database file */
        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_START, 0);
        rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
        if( rc==SQLITE_OK && nSize<nReq ){
          i64 mx = pWal->hdr.mxFrame + (bWal2?walidxGetMxFrame(&pWal->hdr,1):0);
          if( (nSize+65536+mx*szPage)<nReq ){
            /* If the size of the final database is larger than the current
            ** database plus the amount of data in the wal file, plus the
            ** maximum size of the pending-byte page (65536 bytes), then
            ** must be corruption somewhere.  Or in the case of wal2 mode,
            ** plus the amount of data in both wal files. */
            rc = SQLITE_CORRUPT_BKPT;
          }else{
            sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT,&nReq);
          }
        }

      }

      /* Iterate through the contents of the WAL, copying data to the db file */
      while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
        i64 iOffset;

        assert( bWal2==1 || walFramePgno(pWal, iFrame)==iDbpage );
        assert( bWal2==0 || walFramePgno2(pWal, iCkpt, iFrame)==iDbpage );

        SEH_INJECT_FAULT;
        if( AtomicLoad(&db->u1.isInterrupted) ){
          rc = db->mallocFailed ? SQLITE_NOMEM_BKPT : SQLITE_INTERRUPT;
          break;
        }
        if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ){
          assert( bWal2==0 || iDbpage>mxPage );
          continue;
        }
        iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
        WALTRACE(("WAL%p: checkpoint frame %d of wal %d to db page %d\n",
              pWal, (int)iFrame, iCkpt, (int)iDbpage
        ));
        /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
        rc = sqlite3OsRead(pWalFd, zBuf, szPage, iOffset);
        if( rc!=SQLITE_OK ) break;
        iOffset = (iDbpage-1)*(i64)szPage;
        testcase( IS_BIG_INT(iOffset) );
        rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
        if( rc!=SQLITE_OK ) break;
      }
      sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_CKPT_DONE, 0);

      /* If work was actually accomplished, truncate the db file, sync the wal
      ** file and set WalCkptInfo.nBackfill to indicate so. */
      if( rc==SQLITE_OK && (bWal2 || mxSafeFrame==walIndexHdr(pWal)->mxFrame) ){
        if( !bWal2 ){
          i64 szDb = pWal->hdr.nPage*(i64)szPage;
          testcase( IS_BIG_INT(szDb) );
          rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
        }
        if( rc==SQLITE_OK ){
          rc = sqlite3OsSync(pWal->pDbFd, CKPT_SYNC_FLAGS(sync_flags));
        }
      }
      if( rc==SQLITE_OK ){
        AtomicStore(&pInfo->nBackfill, (bWal2 ? 1 : mxSafeFrame));

        SEH_INJECT_FAULT;
      }

      /* Release the reader lock held while backfilling */
      if( bWal2==0 ){
        walUnlockExclusive(pWal, WAL_READ_LOCK(0), 1);
      }
    }

    if( rc==SQLITE_BUSY ){
      /* Reset the return code so as not to report a checkpoint failure
      ** just because there are active readers.  */
      rc = SQLITE_OK;
    }
    if( bWal2 ) wal2CheckpointFinished(pWal, iCkpt);
  }

  /* If this is an SQLITE_CHECKPOINT_RESTART or TRUNCATE operation, and the
  ** entire wal file has been copied into the database file, then block
  ** until all readers have finished using the wal file. This ensures that
  ** the next process to write to the database restarts the wal file.
  */
  if( bWal2==0 && rc==SQLITE_OK && eMode!=SQLITE_CHECKPOINT_PASSIVE ){
    assert( pWal->writeLock );
    SEH_INJECT_FAULT;
    if( pInfo->nBackfill<pWal->hdr.mxFrame ){
      rc = SQLITE_BUSY;
    }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
      u32 salt1;
      sqlite3_randomness(4, &salt1);
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374

2375
2376
2377
2378
2379
2380
2381
2382
2383
2384

2385
2386
2387
2388
2389
2390
2391
          ** writer clients should see that the entire log file has been
          ** checkpointed and behave accordingly. This seems unsafe though,
          ** as it would leave the system in a state where the contents of
          ** the wal-index header do not match the contents of the
          ** file-system. To avoid this, update the wal-index header to
          ** indicate that the log file contains zero valid frames.  */
          walRestartHdr(pWal, salt1);
          rc = sqlite3OsTruncate(pWal->pWalFd, 0);
        }
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      }
    }
  }

 walcheckpoint_out:
  SEH_FREE_ON_ERROR(pIter, 0);
  walIteratorFree(pIter);
  return rc;
}

/*
** If the WAL file is currently larger than nMax bytes in size, truncate
** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
*/
static void walLimitSize(Wal *pWal, i64 nMax){

  i64 sz;
  int rx;
  sqlite3BeginBenignMalloc();
  rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
  if( rx==SQLITE_OK && (sz > nMax ) ){
    rx = sqlite3OsTruncate(pWal->pWalFd, nMax);
  }
  sqlite3EndBenignMalloc();
  if( rx ){
    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);

  }
}

#ifdef SQLITE_USE_SEH
/*
** This is the "standard" exception handler used in a few places to handle 
** an exception thrown by reading from the *-shm mapping after it has become







|

















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|
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|
|
|
|
|
|
|
|
>







2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
          ** writer clients should see that the entire log file has been
          ** checkpointed and behave accordingly. This seems unsafe though,
          ** as it would leave the system in a state where the contents of
          ** the wal-index header do not match the contents of the
          ** file-system. To avoid this, update the wal-index header to
          ** indicate that the log file contains zero valid frames.  */
          walRestartHdr(pWal, salt1);
          rc = sqlite3OsTruncate(pWal->apWalFd[0], 0);
        }
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      }
    }
  }

 walcheckpoint_out:
  SEH_FREE_ON_ERROR(pIter, 0);
  walIteratorFree(pIter);
  return rc;
}

/*
** If the WAL file is currently larger than nMax bytes in size, truncate
** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
*/
static void walLimitSize(Wal *pWal, i64 nMax){
  if( isWalMode2(pWal)==0 ){
    i64 sz;
    int rx;
    sqlite3BeginBenignMalloc();
    rx = sqlite3OsFileSize(pWal->apWalFd[0], &sz);
    if( rx==SQLITE_OK && (sz > nMax ) ){
      rx = sqlite3OsTruncate(pWal->apWalFd[0], nMax);
    }
    sqlite3EndBenignMalloc();
    if( rx ){
      sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
    }
  }
}

#ifdef SQLITE_USE_SEH
/*
** This is the "standard" exception handler used in a few places to handle 
** an exception thrown by reading from the *-shm mapping after it has become
2483
2484
2485
2486
2487
2488
2489

2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501

2502
2503
2504

2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526












2527
2528
2529
2530
2531
2532
2533
2534

2535
2536
2537
2538
2539
2540
2541
  u8 *zBuf                        /* Buffer of at least nBuf bytes */
){
  int rc = SQLITE_OK;
  if( pWal ){
    int isDelete = 0;             /* True to unlink wal and wal-index files */

    assert( walAssertLockmask(pWal) );


    /* If an EXCLUSIVE lock can be obtained on the database file (using the
    ** ordinary, rollback-mode locking methods, this guarantees that the
    ** connection associated with this log file is the only connection to
    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **
    ** The EXCLUSIVE lock is not released before returning.
    */
    if( zBuf!=0
     && SQLITE_OK==(rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE))
    ){

      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }

      rc = sqlite3WalCheckpoint(pWal, db,
          SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
      );
      if( rc==SQLITE_OK ){
        int bPersist = -1;
        sqlite3OsFileControlHint(
            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
        );
        if( bPersist!=1 ){
          /* Try to delete the WAL file if the checkpoint completed and
          ** fsynced (rc==SQLITE_OK) and if we are not in persistent-wal
          ** mode (!bPersist) */
          isDelete = 1;
        }else if( pWal->mxWalSize>=0 ){
          /* Try to truncate the WAL file to zero bytes if the checkpoint
          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
          ** to zero bytes as truncating to the journal_size_limit might
          ** leave a corrupt WAL file on disk. */
          walLimitSize(pWal, 0);
        }












      }
    }

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){
      sqlite3BeginBenignMalloc();
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);

      sqlite3EndBenignMalloc();
    }
    WALTRACE(("WAL%p: closed\n", pWal));
    sqlite3_free((void *)pWal->apWiData);
    sqlite3_free(pWal);
  }
  return rc;







>












>



>
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<



>







3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155

3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
  u8 *zBuf                        /* Buffer of at least nBuf bytes */
){
  int rc = SQLITE_OK;
  if( pWal ){
    int isDelete = 0;             /* True to unlink wal and wal-index files */

    assert( walAssertLockmask(pWal) );
    pWal->bClosing = 1;

    /* If an EXCLUSIVE lock can be obtained on the database file (using the
    ** ordinary, rollback-mode locking methods, this guarantees that the
    ** connection associated with this log file is the only connection to
    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **
    ** The EXCLUSIVE lock is not released before returning.
    */
    if( zBuf!=0
     && SQLITE_OK==(rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE))
    ){
      int i;
      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      for(i=0; rc==SQLITE_OK && i<2; i++){
        rc = sqlite3WalCheckpoint(pWal, db, 
            SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
        );
        if( rc==SQLITE_OK ){
          int bPersist = -1;
          sqlite3OsFileControlHint(
              pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
          );
          if( bPersist!=1 ){
            /* Try to delete the WAL file if the checkpoint completed and
            ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
            ** mode (!bPersist) */
            isDelete = 1;
          }else if( pWal->mxWalSize>=0 ){
            /* Try to truncate the WAL file to zero bytes if the checkpoint
            ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
            ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
            ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
            ** to zero bytes as truncating to the journal_size_limit might
            ** leave a corrupt WAL file on disk. */
            walLimitSize(pWal, 0);
          }
        }

        if( isWalMode2(pWal)==0 ) break;

        SEH_TRY {
          walCkptInfo(pWal)->nBackfill = 0;
          walidxSetFile(&pWal->hdr, !walidxGetFile(&pWal->hdr));
          pWal->writeLock = 1;
          walIndexWriteHdr(pWal);
          pWal->writeLock = 0;
        } 
        SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
      }
    }

    walIndexClose(pWal, isDelete);

    if( isDelete ){
      sqlite3BeginBenignMalloc();
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName2, 0);
      sqlite3EndBenignMalloc();
    }
    WALTRACE(("WAL%p: closed\n", pWal));
    sqlite3_free((void *)pWal->apWiData);
    sqlite3_free(pWal);
  }
  return rc;
2705
2706
2707
2708
2709
2710
2711
2712


2713
2714
2715
2716
2717
2718
2719
    }
  }

  /* If the header is read successfully, check the version number to make
  ** sure the wal-index was not constructed with some future format that
  ** this version of SQLite cannot understand.
  */
  if( badHdr==0 && pWal->hdr.iVersion!=WALINDEX_MAX_VERSION ){


    rc = SQLITE_CANTOPEN_BKPT;
  }
  if( pWal->bShmUnreliable ){
    if( rc!=SQLITE_OK ){
      walIndexClose(pWal, 0);
      pWal->bShmUnreliable = 0;
      assert( pWal->nWiData>0 && pWal->apWiData[0]==0 );







|
>
>







3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
    }
  }

  /* If the header is read successfully, check the version number to make
  ** sure the wal-index was not constructed with some future format that
  ** this version of SQLite cannot understand.
  */
  if( badHdr==0 
   && pWal->hdr.iVersion!=WAL_VERSION1 && pWal->hdr.iVersion!=WAL_VERSION2
  ){
    rc = SQLITE_CANTOPEN_BKPT;
  }
  if( pWal->bShmUnreliable ){
    if( rc!=SQLITE_OK ){
      walIndexClose(pWal, 0);
      pWal->bShmUnreliable = 0;
      assert( pWal->nWiData>0 && pWal->apWiData[0]==0 );
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
  ** into pWal->hdr.
  */
  memcpy(&pWal->hdr, (void*)walIndexHdr(pWal), sizeof(WalIndexHdr));

  /* Make sure some writer hasn't come in and changed the WAL file out
  ** from under us, then disconnected, while we were not looking.
  */
  rc = sqlite3OsFileSize(pWal->pWalFd, &szWal);
  if( rc!=SQLITE_OK ){
    goto begin_unreliable_shm_out;
  }
  if( szWal<WAL_HDRSIZE ){
    /* If the wal file is too small to contain a wal-header and the
    ** wal-index header has mxFrame==0, then it must be safe to proceed
    ** reading the database file only. However, the page cache cannot
    ** be trusted, as a read/write connection may have connected, written
    ** the db, run a checkpoint, truncated the wal file and disconnected
    ** since this client's last read transaction.  */
    *pChanged = 1;
    rc = (pWal->hdr.mxFrame==0 ? SQLITE_OK : WAL_RETRY);
    goto begin_unreliable_shm_out;
  }

  /* Check the salt keys at the start of the wal file still match. */
  rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
  if( rc!=SQLITE_OK ){
    goto begin_unreliable_shm_out;
  }
  if( memcmp(&pWal->hdr.aSalt, &aBuf[16], 8) ){
    /* Some writer has wrapped the WAL file while we were not looking.
    ** Return WAL_RETRY which will cause the in-memory WAL-index to be
    ** rebuilt. */







|
















|







3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
  ** into pWal->hdr.
  */
  memcpy(&pWal->hdr, (void*)walIndexHdr(pWal), sizeof(WalIndexHdr));

  /* Make sure some writer hasn't come in and changed the WAL file out
  ** from under us, then disconnected, while we were not looking.
  */
  rc = sqlite3OsFileSize(pWal->apWalFd[0], &szWal);
  if( rc!=SQLITE_OK ){
    goto begin_unreliable_shm_out;
  }
  if( szWal<WAL_HDRSIZE ){
    /* If the wal file is too small to contain a wal-header and the
    ** wal-index header has mxFrame==0, then it must be safe to proceed
    ** reading the database file only. However, the page cache cannot
    ** be trusted, as a read/write connection may have connected, written
    ** the db, run a checkpoint, truncated the wal file and disconnected
    ** since this client's last read transaction.  */
    *pChanged = 1;
    rc = (pWal->hdr.mxFrame==0 ? SQLITE_OK : WAL_RETRY);
    goto begin_unreliable_shm_out;
  }

  /* Check the salt keys at the start of the wal file still match. */
  rc = sqlite3OsRead(pWal->apWalFd[0], aBuf, WAL_HDRSIZE, 0);
  if( rc!=SQLITE_OK ){
    goto begin_unreliable_shm_out;
  }
  if( memcmp(&pWal->hdr.aSalt, &aBuf[16], 8) ){
    /* Some writer has wrapped the WAL file while we were not looking.
    ** Return WAL_RETRY which will cause the in-memory WAL-index to be
    ** rebuilt. */
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
      iOffset+szFrame<=szWal;
      iOffset+=szFrame
  ){
    u32 pgno;                   /* Database page number for frame */
    u32 nTruncate;              /* dbsize field from frame header */

    /* Read and decode the next log frame. */
    rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
    if( rc!=SQLITE_OK ) break;
    if( !walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame) ) break;

    /* If nTruncate is non-zero, then a complete transaction has been
    ** appended to this wal file. Set rc to WAL_RETRY and break out of
    ** the loop.  */
    if( nTruncate ){







|







3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
      iOffset+szFrame<=szWal;
      iOffset+=szFrame
  ){
    u32 pgno;                   /* Database page number for frame */
    u32 nTruncate;              /* dbsize field from frame header */

    /* Read and decode the next log frame. */
    rc = sqlite3OsRead(pWal->apWalFd[0], aFrame, szFrame, iOffset);
    if( rc!=SQLITE_OK ) break;
    if( !walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame) ) break;

    /* If nTruncate is non-zero, then a complete transaction has been
    ** appended to this wal file. Set rc to WAL_RETRY and break out of
    ** the loop.  */
    if( nTruncate ){
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
** checkpoint process do as much work as possible.  This routine might
** update values of the aReadMark[] array in the header, but if it does
** so it takes care to hold an exclusive lock on the corresponding
** WAL_READ_LOCK() while changing values.
*/
static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
  volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
  u32 mxReadMark;                 /* Largest aReadMark[] value */
  int mxI;                        /* Index of largest aReadMark[] value */
  int i;                          /* Loop counter */
  int rc = SQLITE_OK;             /* Return code  */
  u32 mxFrame;                    /* Wal frame to lock to */
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  int nBlockTmout = 0;
#endif

  assert( pWal->readLock<0 );     /* Not currently locked */

  /* useWal may only be set for read/write connections */
  assert( (pWal->readOnly & WAL_SHM_RDONLY)==0 || useWal==0 );

  /* Take steps to avoid spinning forever if there is a protocol error.
  **
  ** Circumstances that cause a RETRY should only last for the briefest







<
<
<

<




|







3608
3609
3610
3611
3612
3613
3614



3615

3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
** checkpoint process do as much work as possible.  This routine might
** update values of the aReadMark[] array in the header, but if it does
** so it takes care to hold an exclusive lock on the corresponding
** WAL_READ_LOCK() while changing values.
*/
static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int *pCnt){
  volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */



  int rc = SQLITE_OK;             /* Return code  */

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
  int nBlockTmout = 0;
#endif

  assert( pWal->readLock==WAL_LOCK_NONE );     /* Not currently locked */

  /* useWal may only be set for read/write connections */
  assert( (pWal->readOnly & WAL_SHM_RDONLY)==0 || useWal==0 );

  /* Take steps to avoid spinning forever if there is a protocol error.
  **
  ** Circumstances that cause a RETRY should only last for the briefest
3091
3092
3093
3094
3095
3096
3097
































3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187

3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232

3233
3234
3235
3236
3237
3238
3239
    }
  }

  assert( pWal->nWiData>0 );
  assert( pWal->apWiData[0]!=0 );
  pInfo = walCkptInfo(pWal);
  SEH_INJECT_FAULT;
































  if( !useWal && AtomicLoad(&pInfo->nBackfill)==pWal->hdr.mxFrame
#ifdef SQLITE_ENABLE_SNAPSHOT
   && (pWal->pSnapshot==0 || pWal->hdr.mxFrame==0)
#endif
  ){
    /* The WAL has been completely backfilled (or it is empty).
    ** and can be safely ignored.
    */
    rc = walLockShared(pWal, WAL_READ_LOCK(0));
    walShmBarrier(pWal);
    if( rc==SQLITE_OK ){
      if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr)) ){
        /* It is not safe to allow the reader to continue here if frames
        ** may have been appended to the log before READ_LOCK(0) was obtained.
        ** When holding READ_LOCK(0), the reader ignores the entire log file,
        ** which implies that the database file contains a trustworthy
        ** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
        ** happening, this is usually correct.
        **
        ** However, if frames have been appended to the log (or if the log
        ** is wrapped and written for that matter) before the READ_LOCK(0)
        ** is obtained, that is not necessarily true. A checkpointer may
        ** have started to backfill the appended frames but crashed before
        ** it finished. Leaving a corrupt image in the database file.
        */
        walUnlockShared(pWal, WAL_READ_LOCK(0));
        return WAL_RETRY;
      }
      pWal->readLock = 0;
      return SQLITE_OK;
    }else if( rc!=SQLITE_BUSY ){
      return rc;
    }
  }

  /* If we get this far, it means that the reader will want to use
  ** the WAL to get at content from recent commits.  The job now is
  ** to select one of the aReadMark[] entries that is closest to
  ** but not exceeding pWal->hdr.mxFrame and lock that entry.
  */
  mxReadMark = 0;
  mxI = 0;
  mxFrame = pWal->hdr.mxFrame;
#ifdef SQLITE_ENABLE_SNAPSHOT
  if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
    mxFrame = pWal->pSnapshot->mxFrame;
  }
#endif
  for(i=1; i<WAL_NREADER; i++){
    u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
    if( mxReadMark<=thisMark && thisMark<=mxFrame ){
      assert( thisMark!=READMARK_NOT_USED );
      mxReadMark = thisMark;
      mxI = i;
    }
  }
  if( (pWal->readOnly & WAL_SHM_RDONLY)==0
   && (mxReadMark<mxFrame || mxI==0)
  ){
    for(i=1; i<WAL_NREADER; i++){
      rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
      if( rc==SQLITE_OK ){
        AtomicStore(pInfo->aReadMark+i,mxFrame);
        mxReadMark = mxFrame;
        mxI = i;
        walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
        break;
      }else if( rc!=SQLITE_BUSY ){
        return rc;
      }
    }
  }
  if( mxI==0 ){
    assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
    return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTINIT;
  }

  (void)walEnableBlockingMs(pWal, nBlockTmout);
  rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
  walDisableBlocking(pWal);
  if( rc ){
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
    if( rc==SQLITE_BUSY_TIMEOUT ){
      *pCnt |= WAL_RETRY_BLOCKED_MASK;
    }
#else
    assert( rc!=SQLITE_BUSY_TIMEOUT );
#endif
    assert( (rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT );
    return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;

  }
  /* Now that the read-lock has been obtained, check that neither the
  ** value in the aReadMark[] array or the contents of the wal-index
  ** header have changed.
  **
  ** It is necessary to check that the wal-index header did not change
  ** between the time it was read and when the shared-lock was obtained
  ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
  ** that the log file may have been wrapped by a writer, or that frames
  ** that occur later in the log than pWal->hdr.mxFrame may have been
  ** copied into the database by a checkpointer. If either of these things
  ** happened, then reading the database with the current value of
  ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
  ** instead.
  **
  ** Before checking that the live wal-index header has not changed
  ** since it was read, set Wal.minFrame to the first frame in the wal
  ** file that has not yet been checkpointed. This client will not need
  ** to read any frames earlier than minFrame from the wal file - they
  ** can be safely read directly from the database file.
  **
  ** Because a ShmBarrier() call is made between taking the copy of
  ** nBackfill and checking that the wal-header in shared-memory still
  ** matches the one cached in pWal->hdr, it is guaranteed that the
  ** checkpointer that set nBackfill was not working with a wal-index
  ** header newer than that cached in pWal->hdr. If it were, that could
  ** cause a problem. The checkpointer could omit to checkpoint
  ** a version of page X that lies before pWal->minFrame (call that version
  ** A) on the basis that there is a newer version (version B) of the same
  ** page later in the wal file. But if version B happens to like past
  ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
  ** that it can read version A from the database file. However, since
  ** we can guarantee that the checkpointer that set nBackfill could not
  ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
  */
  pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
  walShmBarrier(pWal);
  if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
   || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
  ){
    walUnlockShared(pWal, WAL_READ_LOCK(mxI));
    return WAL_RETRY;
  }else{
    assert( mxReadMark<=pWal->hdr.mxFrame );
    pWal->readLock = (i16)mxI;

  }
  return rc;
}

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** This function does the work of sqlite3WalSnapshotRecover().







>
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>







3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
    }
  }

  assert( pWal->nWiData>0 );
  assert( pWal->apWiData[0]!=0 );
  pInfo = walCkptInfo(pWal);
  SEH_INJECT_FAULT;
  if( isWalMode2(pWal) ){
    /* This connection needs a "part" lock on the current wal file and, 
    ** unless pInfo->nBackfill is set to indicate that it has already been
    ** checkpointed, a "full" lock on the other wal file.  */
    int iWal = walidxGetFile(&pWal->hdr);
    int nBackfill = pInfo->nBackfill || walidxGetMxFrame(&pWal->hdr, !iWal)==0;
    int eLock = 1 + (iWal*2) + (nBackfill==iWal);

    assert( nBackfill==0 || nBackfill==1 );
    assert( iWal==0 || iWal==1 );
    assert( iWal!=0 || nBackfill!=1 || eLock==WAL_LOCK_PART1 );
    assert( iWal!=0 || nBackfill!=0 || eLock==WAL_LOCK_PART1_FULL2 );
    assert( iWal!=1 || nBackfill!=1 || eLock==WAL_LOCK_PART2 );
    assert( iWal!=1 || nBackfill!=0 || eLock==WAL_LOCK_PART2_FULL1 );

    rc = walLockShared(pWal, WAL_READ_LOCK(eLock));
    if( rc!=SQLITE_OK ){
      return (rc==SQLITE_BUSY ? WAL_RETRY : rc);
    }
    walShmBarrier(pWal);
    if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr)) ){
      walUnlockShared(pWal, WAL_READ_LOCK(eLock));
      return WAL_RETRY;
    }else{
      pWal->readLock = eLock;
    }
    assert( pWal->minFrame==0 && walFramePage(pWal->minFrame)==0 );
  }else{
    u32 mxReadMark;               /* Largest aReadMark[] value */
    int mxI;                      /* Index of largest aReadMark[] value */
    int i;                        /* Loop counter */
    u32 mxFrame;                  /* Wal frame to lock to */
    if( !useWal && pInfo->nBackfill==pWal->hdr.mxFrame
  #ifdef SQLITE_ENABLE_SNAPSHOT
     && (pWal->pSnapshot==0 || pWal->hdr.mxFrame==0)
  #endif
    ){
      /* The WAL has been completely backfilled (or it is empty).
      ** and can be safely ignored.
      */
      rc = walLockShared(pWal, WAL_READ_LOCK(0));
      walShmBarrier(pWal);
      if( rc==SQLITE_OK ){
        if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr,sizeof(WalIndexHdr)) ){
          /* It is not safe to allow the reader to continue here if frames
          ** may have been appended to the log before READ_LOCK(0) was obtained.
          ** When holding READ_LOCK(0), the reader ignores the entire log file,
          ** which implies that the database file contains a trustworthy
          ** snapshot. Since holding READ_LOCK(0) prevents a checkpoint from
          ** happening, this is usually correct.
          **
          ** However, if frames have been appended to the log (or if the log 
          ** is wrapped and written for that matter) before the READ_LOCK(0)
          ** is obtained, that is not necessarily true. A checkpointer may
          ** have started to backfill the appended frames but crashed before
          ** it finished. Leaving a corrupt image in the database file.
          */
          walUnlockShared(pWal, WAL_READ_LOCK(0));
          return WAL_RETRY;
        }
        pWal->readLock = 0;
        return SQLITE_OK;
      }else if( rc!=SQLITE_BUSY ){
        return rc;
      }
    }
  
    /* If we get this far, it means that the reader will want to use
    ** the WAL to get at content from recent commits.  The job now is
    ** to select one of the aReadMark[] entries that is closest to
    ** but not exceeding pWal->hdr.mxFrame and lock that entry.
    */
    mxReadMark = 0;
    mxI = 0;
    mxFrame = pWal->hdr.mxFrame;
  #ifdef SQLITE_ENABLE_SNAPSHOT
    if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
      mxFrame = pWal->pSnapshot->mxFrame;
    }
  #endif
    for(i=1; i<WAL_NREADER; i++){
      u32 thisMark = AtomicLoad(pInfo->aReadMark+i); SEH_INJECT_FAULT;
      if( mxReadMark<=thisMark && thisMark<=mxFrame ){
        assert( thisMark!=READMARK_NOT_USED );
        mxReadMark = thisMark;
        mxI = i;
      }
    }
    if( (pWal->readOnly & WAL_SHM_RDONLY)==0
     && (mxReadMark<mxFrame || mxI==0)
    ){
      for(i=1; i<WAL_NREADER; i++){
        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
        if( rc==SQLITE_OK ){
          AtomicStore(pInfo->aReadMark+i,mxFrame);
          mxReadMark = mxFrame;
          mxI = i;
          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
          break;
        }else if( rc!=SQLITE_BUSY ){
          return rc;
        }
      }
    }
    if( mxI==0 ){
      assert( rc==SQLITE_BUSY || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
      return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTINIT;
    }
  
    (void)walEnableBlockingMs(pWal, nBlockTmout);
    rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
    walDisableBlocking(pWal);
    if( rc ){
#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
      if( rc==SQLITE_BUSY_TIMEOUT ){
        *pCnt |= WAL_RETRY_BLOCKED_MASK;
      }
#else
      assert( rc!=SQLITE_BUSY_TIMEOUT );
#endif
      assert((rc&0xFF)!=SQLITE_BUSY||rc==SQLITE_BUSY||rc==SQLITE_BUSY_TIMEOUT);
      return (rc&0xFF)==SQLITE_BUSY ? WAL_RETRY : rc;

    }
    /* Now that the read-lock has been obtained, check that neither the
    ** value in the aReadMark[] array or the contents of the wal-index
    ** header have changed.
    **
    ** It is necessary to check that the wal-index header did not change
    ** between the time it was read and when the shared-lock was obtained
    ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
    ** that the log file may have been wrapped by a writer, or that frames
    ** that occur later in the log than pWal->hdr.mxFrame may have been
    ** copied into the database by a checkpointer. If either of these things
    ** happened, then reading the database with the current value of
    ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
    ** instead.
    **
    ** Before checking that the live wal-index header has not changed
    ** since it was read, set Wal.minFrame to the first frame in the wal
    ** file that has not yet been checkpointed. This client will not need
    ** to read any frames earlier than minFrame from the wal file - they
    ** can be safely read directly from the database file.
    **
    ** Because a ShmBarrier() call is made between taking the copy of 
    ** nBackfill and checking that the wal-header in shared-memory still
    ** matches the one cached in pWal->hdr, it is guaranteed that the 
    ** checkpointer that set nBackfill was not working with a wal-index
    ** header newer than that cached in pWal->hdr. If it were, that could
    ** cause a problem. The checkpointer could omit to checkpoint
    ** a version of page X that lies before pWal->minFrame (call that version
    ** A) on the basis that there is a newer version (version B) of the same
    ** page later in the wal file. But if version B happens to like past
    ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
    ** that it can read version A from the database file. However, since
    ** we can guarantee that the checkpointer that set nBackfill could not
    ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
    */
    pWal->minFrame = AtomicLoad(&pInfo->nBackfill)+1; SEH_INJECT_FAULT;
    walShmBarrier(pWal);
    if( AtomicLoad(pInfo->aReadMark+mxI)!=mxReadMark
     || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
    ){
      walUnlockShared(pWal, WAL_READ_LOCK(mxI));
      return WAL_RETRY;
    }else{
      assert( mxReadMark<=pWal->hdr.mxFrame );
      pWal->readLock = (i16)mxI;
    }
  }
  return rc;
}

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** This function does the work of sqlite3WalSnapshotRecover().
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
      if( rc!=SQLITE_OK ) break;
      assert( i - sLoc.iZero - 1 >=0 );
      pgno = sLoc.aPgno[i-sLoc.iZero-1];
      iDbOff = (i64)(pgno-1) * szPage;

      if( iDbOff+szPage<=szDb ){
        iWalOff = walFrameOffset(i, szPage) + WAL_FRAME_HDRSIZE;
        rc = sqlite3OsRead(pWal->pWalFd, pBuf1, szPage, iWalOff);

        if( rc==SQLITE_OK ){
          rc = sqlite3OsRead(pWal->pDbFd, pBuf2, szPage, iDbOff);
        }

        if( rc!=SQLITE_OK || 0==memcmp(pBuf1, pBuf2, szPage) ){
          break;







|







3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
      if( rc!=SQLITE_OK ) break;
      assert( i - sLoc.iZero - 1 >=0 );
      pgno = sLoc.aPgno[i-sLoc.iZero-1];
      iDbOff = (i64)(pgno-1) * szPage;

      if( iDbOff+szPage<=szDb ){
        iWalOff = walFrameOffset(i, szPage) + WAL_FRAME_HDRSIZE;
        rc = sqlite3OsRead(pWal->apWalFd[0], pBuf1, szPage, iWalOff);

        if( rc==SQLITE_OK ){
          rc = sqlite3OsRead(pWal->pDbFd, pBuf2, szPage, iDbOff);
        }

        if( rc!=SQLITE_OK || 0==memcmp(pBuf1, pBuf2, szPage) ){
          break;
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3303
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3306



3307
3308
3309
3310
3311
3312
3313
**
** SQLITE_OK is returned if successful, or an SQLite error code if an
** error occurs. It is not an error if nBackfillAttempted cannot be
** decreased at all.
*/
int sqlite3WalSnapshotRecover(Wal *pWal){
  int rc;




  assert( pWal->readLock>=0 );
  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
  if( rc==SQLITE_OK ){
    void *pBuf1 = sqlite3_malloc(pWal->szPage);
    void *pBuf2 = sqlite3_malloc(pWal->szPage);
    if( pBuf1==0 || pBuf2==0 ){







>
>
>







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**
** SQLITE_OK is returned if successful, or an SQLite error code if an
** error occurs. It is not an error if nBackfillAttempted cannot be
** decreased at all.
*/
int sqlite3WalSnapshotRecover(Wal *pWal){
  int rc;

  /* Snapshots may not be used with wal2 mode databases. */
  if( isWalMode2(pWal) ) return SQLITE_ERROR;

  assert( pWal->readLock>=0 );
  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
  if( rc==SQLITE_OK ){
    void *pBuf1 = sqlite3_malloc(pWal->szPage);
    void *pBuf2 = sqlite3_malloc(pWal->szPage);
    if( pBuf1==0 || pBuf2==0 ){
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#endif

  assert( pWal->ckptLock==0 );
  assert( pWal->nSehTry>0 );

#ifdef SQLITE_ENABLE_SNAPSHOT
  if( pSnapshot ){

    if( memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
      bChanged = 1;
    }

    /* It is possible that there is a checkpointer thread running
    ** concurrent with this code. If this is the case, it may be that the
    ** checkpointer has already determined that it will checkpoint







>







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#endif

  assert( pWal->ckptLock==0 );
  assert( pWal->nSehTry>0 );

#ifdef SQLITE_ENABLE_SNAPSHOT
  if( pSnapshot ){
    if( isWalMode2(pWal) ) return SQLITE_ERROR;
    if( memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
      bChanged = 1;
    }

    /* It is possible that there is a checkpointer thread running
    ** concurrent with this code. If this is the case, it may be that the
    ** checkpointer has already determined that it will checkpoint
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3380




3381
3382
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3384
3385
3386
3387
  do{
    rc = walTryBeginRead(pWal, pChanged, 0, &cnt);
  }while( rc==WAL_RETRY );
  testcase( (rc&0xff)==SQLITE_BUSY );
  testcase( (rc&0xff)==SQLITE_IOERR );
  testcase( rc==SQLITE_PROTOCOL );
  testcase( rc==SQLITE_OK );





#ifdef SQLITE_ENABLE_SNAPSHOT
  if( rc==SQLITE_OK ){
    if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
      /* At this point the client has a lock on an aReadMark[] slot holding
      ** a value equal to or smaller than pSnapshot->mxFrame, but pWal->hdr
      ** is populated with the wal-index header corresponding to the head







>
>
>
>







4035
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  do{
    rc = walTryBeginRead(pWal, pChanged, 0, &cnt);
  }while( rc==WAL_RETRY );
  testcase( (rc&0xff)==SQLITE_BUSY );
  testcase( (rc&0xff)==SQLITE_IOERR );
  testcase( rc==SQLITE_PROTOCOL );
  testcase( rc==SQLITE_OK );
  
  if( rc==SQLITE_OK && pWal->hdr.iVersion==WAL_VERSION2 ){
    rc = walOpenWal2(pWal);
  }

#ifdef SQLITE_ENABLE_SNAPSHOT
  if( rc==SQLITE_OK ){
    if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
      /* At this point the client has a lock on an aReadMark[] slot holding
      ** a value equal to or smaller than pSnapshot->mxFrame, but pWal->hdr
      ** is populated with the wal-index header corresponding to the head
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3496
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3500





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3568
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  int rc;
  SEH_TRY {
    rc = walBeginReadTransaction(pWal, pChanged);
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )
  return rc;
}


/*
** Finish with a read transaction.  All this does is release the
** read-lock.
*/
void sqlite3WalEndReadTransaction(Wal *pWal){
  sqlite3WalEndWriteTransaction(pWal);
  if( pWal->readLock>=0 ){
    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
    pWal->readLock = -1;
  }






















































































}

/*
** Search the wal file for page pgno. If found, set *piRead to the frame that
** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
** to zero.
**
** Return SQLITE_OK if successful, or an error code if an error occurs. If an
** error does occur, the final value of *piRead is undefined.
*/
static int walFindFrame(
  Wal *pWal,                      /* WAL handle */
  Pgno pgno,                      /* Database page number to read data for */
  u32 *piRead                     /* OUT: Frame number (or zero) */
){



  u32 iRead = 0;                  /* If !=0, WAL frame to return data from */
  u32 iLast = pWal->hdr.mxFrame;  /* Last page in WAL for this reader */
  int iHash;                      /* Used to loop through N hash tables */
  int iMinHash;

  /* This routine is only be called from within a read transaction. */


  assert( pWal->readLock>=0 || pWal->lockError );

  /* If the "last page" field of the wal-index header snapshot is 0, then
  ** no data will be read from the wal under any circumstances. Return early


  ** in this case as an optimization.  Likewise, if pWal->readLock==0,





  ** then the WAL is ignored by the reader so return early, as if the
  ** WAL were empty.
  */

  if( iLast==0 || (pWal->readLock==0 && pWal->bShmUnreliable==0) ){
    *piRead = 0;
    return SQLITE_OK;
  }

  /* Search the hash table or tables for an entry matching page number
  ** pgno. Each iteration of the following for() loop searches one
  ** hash table (each hash table indexes up to HASHTABLE_NPAGE frames).


  **
  ** This code might run concurrently to the code in walIndexAppend()
  ** that adds entries to the wal-index (and possibly to this hash
  ** table). This means the value just read from the hash
  ** slot (aHash[iKey]) may have been added before or after the
  ** current read transaction was opened. Values added after the
  ** read transaction was opened may have been written incorrectly -
  ** i.e. these slots may contain garbage data. However, we assume
  ** that any slots written before the current read transaction was
  ** opened remain unmodified.
  **
  ** For the reasons above, the if(...) condition featured in the inner
  ** loop of the following block is more stringent that would be required
  ** if we had exclusive access to the hash-table:
  **
  **   (aPgno[iFrame]==pgno):
  **     This condition filters out normal hash-table collisions.
  **
  **   (iFrame<=iLast):
  **     This condition filters out entries that were added to the hash
  **     table after the current read-transaction had started.
  */

  iMinHash = walFramePage(pWal->minFrame);
  for(iHash=walFramePage(iLast); iHash>=iMinHash; iHash--){
    WalHashLoc sLoc;              /* Hash table location */


    int iKey;                     /* Hash slot index */
    int nCollide;                 /* Number of hash collisions remaining */
    int rc;                       /* Error code */
    u32 iH;

    rc = walHashGet(pWal, iHash, &sLoc);

    if( rc!=SQLITE_OK ){
      return rc;
    }
    nCollide = HASHTABLE_NSLOT;
    iKey = walHash(pgno);
    SEH_INJECT_FAULT;
    while( (iH = AtomicLoad(&sLoc.aHash[iKey]))!=0 ){
      u32 iFrame = iH + sLoc.iZero;
      if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH-1]==pgno ){
        assert( iFrame>iRead || CORRUPT_DB );
        iRead = iFrame;
      }
      if( (nCollide--)==0 ){
        *piRead = 0;
        return SQLITE_CORRUPT_BKPT;

      }
      iKey = walNextHash(iKey);
    }
    if( iRead ) break;
  }

#ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
  /* If expensive assert() statements are available, do a linear search
  ** of the wal-index file content. Make sure the results agree with the
  ** result obtained using the hash indexes above.  */



  {
    u32 iRead2 = 0;
    u32 iTest;
    assert( pWal->bShmUnreliable || pWal->minFrame>0 );
    for(iTest=iLast; iTest>=pWal->minFrame && iTest>0; iTest--){
      if( walFramePgno(pWal, iTest)==pgno ){
        iRead2 = iTest;







>







|

|

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<
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<

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|
>
>
>







4122
4123
4124
4125
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4127
4128
4129
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4134
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4246
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4274
4275
4276
















4277
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4279
4280




4281

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4283






4284

4285
4286
4287



4288
4289


4290
4291

4292
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4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
  int rc;
  SEH_TRY {
    rc = walBeginReadTransaction(pWal, pChanged);
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )
  return rc;
}


/*
** Finish with a read transaction.  All this does is release the
** read-lock.
*/
void sqlite3WalEndReadTransaction(Wal *pWal){
  sqlite3WalEndWriteTransaction(pWal);
  if( pWal->readLock!=WAL_LOCK_NONE ){
    walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
    pWal->readLock = WAL_LOCK_NONE;
  }
}

/* Search hash table iHash for an entry matching page number
** pgno. Each call to this function searches a single hash table
** (each hash table indexes up to HASHTABLE_NPAGE frames).
**
** This code might run concurrently to the code in walIndexAppend()
** that adds entries to the wal-index (and possibly to this hash 
** table). This means the value just read from the hash 
** slot (aHash[iKey]) may have been added before or after the 
** current read transaction was opened. Values added after the
** read transaction was opened may have been written incorrectly -
** i.e. these slots may contain garbage data. However, we assume
** that any slots written before the current read transaction was
** opened remain unmodified.
**
** For the reasons above, the if(...) condition featured in the inner
** loop of the following block is more stringent that would be required 
** if we had exclusive access to the hash-table:
**
**   (aPgno[iFrame]==pgno): 
**     This condition filters out normal hash-table collisions.
**
**   (iFrame<=iLast): 
**     This condition filters out entries that were added to the hash
**     table after the current read-transaction had started.
*/
static int walSearchHash(
  Wal *pWal, 
  u32 iLast,
  int iHash, 
  Pgno pgno, 
  u32 *piRead
){
  WalHashLoc sLoc;                /* Hash table location */
  int iKey;                       /* Hash slot index */
  int nCollide;                   /* Number of hash collisions remaining */
  int rc;                         /* Error code */
  u32 iH;

  rc = walHashGet(pWal, iHash, &sLoc);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  nCollide = HASHTABLE_NSLOT;
  iKey = walHash(pgno);
  SEH_INJECT_FAULT;
  while( (iH = AtomicLoad(&sLoc.aHash[iKey]))!=0 ){
    u32 iFrame = iH + sLoc.iZero;
    if( iFrame<=iLast && iFrame>=pWal->minFrame && sLoc.aPgno[iH-1]==pgno ){
      assert( iFrame>*piRead || CORRUPT_DB );
      *piRead = iFrame;
    }
    if( (nCollide--)==0 ){
      *piRead = 0;
      return SQLITE_CORRUPT_BKPT;
    }
    iKey = walNextHash(iKey);
  }

  return SQLITE_OK;
}

static int walSearchWal(
  Wal *pWal, 
  int iWal, 
  Pgno pgno, 
  u32 *piRead
){
  int rc = SQLITE_OK;
  int bWal2 = isWalMode2(pWal);
  u32 iLast = walidxGetMxFrame(&pWal->hdr, iWal);
  if( iLast ){
    int iHash;
    int iMinHash = walFramePage(pWal->minFrame);
    u32 iExternal = bWal2 ? walExternalEncode(iWal, iLast) : iLast;
    assert( bWal2==0 || pWal->minFrame==0 );
    for(iHash=walFramePage(iExternal); 
        iHash>=iMinHash && *piRead==0; 
        iHash-=(1+bWal2)
    ){
      rc = walSearchHash(pWal, iExternal, iHash, pgno, piRead);
      if( rc!=SQLITE_OK ) break;
    }
  }
  return rc;
}

/*
** Search the wal file for page pgno. If found, set *piRead to the frame that
** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
** to zero.
**
** Return SQLITE_OK if successful, or an error code if an error occurs. If an
** error does occur, the final value of *piRead is undefined.
*/
static int walFindFrame(
  Wal *pWal,                      /* WAL handle */
  Pgno pgno,                      /* Database page number to read data for */
  u32 *piRead                     /* OUT: Frame number (or zero) */
){
  int bWal2 = isWalMode2(pWal);
  int iApp = walidxGetFile(&pWal->hdr);
  int rc = SQLITE_OK;
  u32 iRead = 0;                  /* If !=0, WAL frame to return data from */




  /* This routine is only be called from within a read transaction. Or,
  ** sometimes, as part of a rollback that occurs after an error reaquiring
  ** a read-lock in walRestartLog().  */
  assert( pWal->readLock!=WAL_LOCK_NONE || pWal->lockError );

  /* If this is a wal2 system, the client must have a partial-wal lock 

  ** on wal file iApp. Or if it is a wal system, iApp==0 must be true.  */
  assert( bWal2==0 || iApp==1
       || pWal->readLock==WAL_LOCK_PART1 || pWal->readLock==WAL_LOCK_PART1_FULL2
  );
  assert( bWal2==0 || iApp==0
       || pWal->readLock==WAL_LOCK_PART2 || pWal->readLock==WAL_LOCK_PART2_FULL1
  );
  assert( bWal2 || iApp==0 );



  /* Return early if read-lock 0 is held. */
  if( (pWal->readLock==0 && pWal->bShmUnreliable==0) ){
    *piRead = 0;
    return SQLITE_OK;
  }

  /* Search the wal file that the client holds a partial lock on first */
  rc = walSearchWal(pWal, iApp, pgno, &iRead);

  /* If the requested page was not found, no error has occured, and 
  ** the client holds a full-wal lock on the other wal file, search it
  ** too.  */


  if( rc==SQLITE_OK && bWal2 && iRead==0 && (
        pWal->readLock==WAL_LOCK_PART1_FULL2 
     || pWal->readLock==WAL_LOCK_PART2_FULL1
















  )){
    rc = walSearchWal(pWal, !iApp, pgno, &iRead);


  }
  if( rc!=SQLITE_OK ) return rc;






#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
  if( iRead ){ 






    u32 iFrame;

    int iWal = walExternalDecode(iRead, &iFrame);
    WALTRACE(("WAL%p: page %d @ frame %d wal %d\n",pWal,(int)pgno,iFrame,iWal));
  }else{



    WALTRACE(("WAL%p: page %d not found\n", pWal, (int)pgno));
  }


#endif


#if  defined(SQLITE_ENABLE_EXPENSIVE_ASSERT) && /*TODO*/ 0
  /* If expensive assert() statements are available, do a linear search
  ** of the wal-index file content. Make sure the results agree with the
  ** result obtained using the hash indexes above.  
  **
  ** TODO: This is broken for wal2.
  */
  {
    u32 iRead2 = 0;
    u32 iTest;
    assert( pWal->bShmUnreliable || pWal->minFrame>0 );
    for(iTest=iLast; iTest>=pWal->minFrame && iTest>0; iTest--){
      if( walFramePgno(pWal, iTest)==pgno ){
        iRead2 = iTest;
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3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621


3622


3623
3624
3625
3626










3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
/*
** Read the contents of frame iRead from the wal file into buffer pOut
** (which is nOut bytes in size). Return SQLITE_OK if successful, or an
** error code otherwise.
*/
int sqlite3WalReadFrame(
  Wal *pWal,                      /* WAL handle */
  u32 iRead,                      /* Frame to read */
  int nOut,                       /* Size of buffer pOut in bytes */
  u8 *pOut                        /* Buffer to write page data to */
){
  int sz;


  i64 iOffset;


  sz = pWal->hdr.szPage;
  sz = (sz&0xfe00) + ((sz&0x0001)<<16);
  testcase( sz<=32768 );
  testcase( sz>=65536 );










  iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
  /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
  return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
}

/*
** Return the size of the database in pages (or zero, if unknown).
*/
Pgno sqlite3WalDbsize(Wal *pWal){
  if( pWal && ALWAYS(pWal->readLock>=0) ){
    return pWal->hdr.nPage;
  }
  return 0;
}


/*







|




>
>

>
>




>
>
>
>
>
>
>
>
>
>


|






|







4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
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4352
4353
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4355
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4360
4361
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4369
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4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
/*
** Read the contents of frame iRead from the wal file into buffer pOut
** (which is nOut bytes in size). Return SQLITE_OK if successful, or an
** error code otherwise.
*/
int sqlite3WalReadFrame(
  Wal *pWal,                      /* WAL handle */
  u32 iExternal,                  /* Frame to read */
  int nOut,                       /* Size of buffer pOut in bytes */
  u8 *pOut                        /* Buffer to write page data to */
){
  int sz;
  int iWal = 0;
  u32 iRead;
  i64 iOffset;

  /* Figure out the page size */
  sz = pWal->hdr.szPage;
  sz = (sz&0xfe00) + ((sz&0x0001)<<16);
  testcase( sz<=32768 );
  testcase( sz>=65536 );

  if( isWalMode2(pWal) ){
    /* Figure out which of the two wal files, and the frame within, that 
    ** iExternal refers to.  */
    iWal = walExternalDecode(iExternal, &iRead);
  }else{
    iRead = iExternal;
  }

  WALTRACE(("WAL%p: reading frame %d wal %d\n", pWal, iRead, iWal));
  iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
  /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
  return sqlite3OsRead(pWal->apWalFd[iWal], pOut, (nOut>sz?sz:nOut), iOffset);
}

/*
** Return the size of the database in pages (or zero, if unknown).
*/
Pgno sqlite3WalDbsize(Wal *pWal){
  if( pWal && ALWAYS(pWal->readLock!=WAL_LOCK_NONE) ){
    return pWal->hdr.nPage;
  }
  return 0;
}


/*
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
    assert( !memcmp(&pWal->hdr,(void *)walIndexHdr(pWal),sizeof(WalIndexHdr)) );
    return SQLITE_OK;
  }
#endif

  /* Cannot start a write transaction without first holding a read
  ** transaction. */
  assert( pWal->readLock>=0 );
  assert( pWal->writeLock==0 && pWal->iReCksum==0 );

  if( pWal->readOnly ){
    return SQLITE_READONLY;
  }

  /* Only one writer allowed at a time.  Get the write lock.  Return







|







4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
    assert( !memcmp(&pWal->hdr,(void *)walIndexHdr(pWal),sizeof(WalIndexHdr)) );
    return SQLITE_OK;
  }
#endif

  /* Cannot start a write transaction without first holding a read
  ** transaction. */
  assert( pWal->readLock!=WAL_LOCK_NONE );
  assert( pWal->writeLock==0 && pWal->iReCksum==0 );

  if( pWal->readOnly ){
    return SQLITE_READONLY;
  }

  /* Only one writer allowed at a time.  Get the write lock.  Return
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701

3702
3703
3704
3705
3706
3707
3708
  ** time the read transaction on this connection was started, then
  ** the write is disallowed.
  */
  SEH_TRY {
    if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){
      rc = SQLITE_BUSY_SNAPSHOT;
    }
  }
  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )

  if( rc!=SQLITE_OK ){
    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
    pWal->writeLock = 0;
  }

  return rc;
}

/*
** End a write transaction.  The commit has already been done.  This
** routine merely releases the lock.
*/







|






>







4433
4434
4435
4436
4437
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4440
4441
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4443
4444
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4447
4448
4449
4450
4451
4452
4453
4454
  ** time the read transaction on this connection was started, then
  ** the write is disallowed.
  */
  SEH_TRY {
    if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){
      rc = SQLITE_BUSY_SNAPSHOT;
    }
  } 
  SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )

  if( rc!=SQLITE_OK ){
    walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
    pWal->writeLock = 0;
  }

  return rc;
}

/*
** End a write transaction.  The commit has already been done.  This
** routine merely releases the lock.
*/
3727
3728
3729
3730
3731
3732
3733


3734
3735


3736
3737
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3739
3740
3741


3742
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3758


3759
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3775

3776
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3790
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3831
























3832

3833
3834
3835
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3837
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3839
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  if( ALWAYS(pWal->writeLock) ){


    Pgno iMax = pWal->hdr.mxFrame;
    Pgno iFrame;



    SEH_TRY {
      /* Restore the clients cache of the wal-index header to the state it
      ** was in before the client began writing to the database. 
      */
      memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));


  
      for(iFrame=pWal->hdr.mxFrame+1; 
          ALWAYS(rc==SQLITE_OK) && iFrame<=iMax; 
          iFrame++
      ){
        /* This call cannot fail. Unless the page for which the page number
        ** is passed as the second argument is (a) in the cache and
        ** (b) has an outstanding reference, then xUndo is either a no-op
        ** (if (a) is false) or simply expels the page from the cache (if (b)
        ** is false).
        **
        ** If the upper layer is doing a rollback, it is guaranteed that there
        ** are no outstanding references to any page other than page 1. And
        ** page 1 is never written to the log until the transaction is
        ** committed. As a result, the call to xUndo may not fail.
        */




        assert( walFramePgno(pWal, iFrame)!=1 );


        rc = xUndo(pUndoCtx, walFramePgno(pWal, iFrame));
      }
      if( iMax!=pWal->hdr.mxFrame ) walCleanupHash(pWal);
    }
    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  }
  return rc;
}

/*
** Argument aWalData must point to an array of WAL_SAVEPOINT_NDATA u32
** values. This function populates the array with values required to
** "rollback" the write position of the WAL handle back to the current
** point in the event of a savepoint rollback (via WalSavepointUndo()).
*/
void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){

  assert( pWal->writeLock );

  aWalData[0] = pWal->hdr.mxFrame;
  aWalData[1] = pWal->hdr.aFrameCksum[0];
  aWalData[2] = pWal->hdr.aFrameCksum[1];
  aWalData[3] = pWal->nCkpt;
}

/*
** Move the write position of the WAL back to the point identified by
** the values in the aWalData[] array. aWalData must point to an array
** of WAL_SAVEPOINT_NDATA u32 values that has been previously populated
** by a call to WalSavepoint().
*/
int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
  int rc = SQLITE_OK;



  assert( pWal->writeLock );

  assert( aWalData[3]!=pWal->nCkpt || aWalData[0]<=pWal->hdr.mxFrame );

  if( aWalData[3]!=pWal->nCkpt ){
    /* This savepoint was opened immediately after the write-transaction
    ** was started. Right after that, the writer decided to wrap around
    ** to the start of the log. Update the savepoint values to match.
    */
    aWalData[0] = 0;
    aWalData[3] = pWal->nCkpt;
  }

  if( aWalData[0]<pWal->hdr.mxFrame ){
    pWal->hdr.mxFrame = aWalData[0];
    pWal->hdr.aFrameCksum[0] = aWalData[1];
    pWal->hdr.aFrameCksum[1] = aWalData[2];
    SEH_TRY {
      walCleanupHash(pWal);
    }
    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  }

  return rc;
}

/*
** This function is called just before writing a set of frames to the log
** file (see sqlite3WalFrames()). It checks to see if, instead of appending
** to the current log file, it is possible to overwrite the start of the
** existing log file with the new frames (i.e. "reset" the log). If so,
** it sets pWal->hdr.mxFrame to 0. Otherwise, pWal->hdr.mxFrame is left
** unchanged.
**
** SQLITE_OK is returned if no error is encountered (regardless of whether
** or not pWal->hdr.mxFrame is modified). An SQLite error code is returned
** if an error occurs.
*/
static int walRestartLog(Wal *pWal){
  int rc = SQLITE_OK;
  int cnt;
































  if( pWal->readLock==0 ){

    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
    assert( pInfo->nBackfill==pWal->hdr.mxFrame );
    if( pInfo->nBackfill>0 ){
      u32 salt1;
      sqlite3_randomness(4, &salt1);
      rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      if( rc==SQLITE_OK ){







>
>
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>



|


>
>
|
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|
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<











>
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>

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|










>
>


>
|

|





|


|
|














|
|
|
|


|




|
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>
>
>
|
>







4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494

4495


4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
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4583
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4591
4592
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4597
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4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
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4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
**
** Otherwise, if the callback function does not return an error, this
** function returns SQLITE_OK.
*/
int sqlite3WalUndo(Wal *pWal, int (*xUndo)(void *, Pgno), void *pUndoCtx){
  int rc = SQLITE_OK;
  if( ALWAYS(pWal->writeLock) ){
    int iWal = walidxGetFile(&pWal->hdr);
    Pgno iMax = walidxGetMxFrame(&pWal->hdr, iWal);
    Pgno iNew;
    Pgno iFrame;

    assert( isWalMode2(pWal) || iWal==0 );

    SEH_TRY {
      /* Restore the clients cache of the wal-index header to the state it
      ** was in before the client began writing to the database.
      */
      memcpy(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr));
      assert( walidxGetFile(&pWal->hdr)==iWal );
      iNew = walidxGetMxFrame(&pWal->hdr, walidxGetFile(&pWal->hdr));


      for(iFrame=iNew+1; ALWAYS(rc==SQLITE_OK) && iFrame<=iMax; iFrame++){


        /* This call cannot fail. Unless the page for which the page number
        ** is passed as the second argument is (a) in the cache and
        ** (b) has an outstanding reference, then xUndo is either a no-op
        ** (if (a) is false) or simply expels the page from the cache (if (b)
        ** is false).
        **
        ** If the upper layer is doing a rollback, it is guaranteed that there
        ** are no outstanding references to any page other than page 1. And
        ** page 1 is never written to the log until the transaction is
        ** committed. As a result, the call to xUndo may not fail.
        */
        Pgno pgno;
        if( isWalMode2(pWal) ){
          pgno = walFramePgno2(pWal, iWal, iFrame);
        }else{
          pgno = walFramePgno(pWal, iFrame);
        }
        assert( pgno!=1 );
        rc = xUndo(pUndoCtx, pgno);
      }
      if( iMax!=iNew ) walCleanupHash(pWal);
    }
    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  }
  return rc;
}

/*
** Argument aWalData must point to an array of WAL_SAVEPOINT_NDATA u32
** values. This function populates the array with values required to
** "rollback" the write position of the WAL handle back to the current
** point in the event of a savepoint rollback (via WalSavepointUndo()).
*/
void sqlite3WalSavepoint(Wal *pWal, u32 *aWalData){
  int iWal = walidxGetFile(&pWal->hdr);
  assert( pWal->writeLock );
  assert( isWalMode2(pWal) || iWal==0 );
  aWalData[0] = walidxGetMxFrame(&pWal->hdr, iWal);
  aWalData[1] = pWal->hdr.aFrameCksum[0];
  aWalData[2] = pWal->hdr.aFrameCksum[1];
  aWalData[3] = isWalMode2(pWal) ? iWal : pWal->nCkpt;
}

/*
** Move the write position of the WAL back to the point identified by
** the values in the aWalData[] array. aWalData must point to an array
** of WAL_SAVEPOINT_NDATA u32 values that has been previously populated
** by a call to WalSavepoint().
*/
int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){
  int rc = SQLITE_OK;
  int iWal = walidxGetFile(&pWal->hdr);
  int iCmp = isWalMode2(pWal) ? iWal : pWal->nCkpt;

  assert( pWal->writeLock );
  assert( isWalMode2(pWal) || iWal==0 );
  assert( aWalData[3]!=iCmp || aWalData[0]<=walidxGetMxFrame(&pWal->hdr,iWal) );

  if( aWalData[3]!=iCmp ){
    /* This savepoint was opened immediately after the write-transaction
    ** was started. Right after that, the writer decided to wrap around
    ** to the start of the log. Update the savepoint values to match.
    */
    aWalData[0] = 0;
    aWalData[3] = iCmp;
  }

  if( aWalData[0]<walidxGetMxFrame(&pWal->hdr, iWal) ){
    walidxSetMxFrame(&pWal->hdr, iWal, aWalData[0]);
    pWal->hdr.aFrameCksum[0] = aWalData[1];
    pWal->hdr.aFrameCksum[1] = aWalData[2];
    SEH_TRY {
      walCleanupHash(pWal);
    }
    SEH_EXCEPT( rc = SQLITE_IOERR_IN_PAGE; )
  }

  return rc;
}

/*
** This function is called just before writing a set of frames to the log
** file (see sqlite3WalFrames()). It checks to see if, instead of appending
** to the current log file, it is possible and desirable to switch to the
** other log file and write the new transaction to the start of it.
** If so, the wal-index header is updated accordingly - both in heap memory
** and in the *-shm file.
**
** SQLITE_OK is returned if no error is encountered (regardless of whether
** or not the wal-index header is modified). An SQLite error code is returned
** if an error occurs.
*/
static int walRestartLog(Wal *pWal){
  int rc = SQLITE_OK;

  if( isWalMode2(pWal) ){
    int iApp = walidxGetFile(&pWal->hdr);
    int nWalSize = WAL_DEFAULT_WALSIZE;
    if( pWal->mxWalSize>0 ){
      nWalSize = (pWal->mxWalSize-WAL_HDRSIZE+pWal->szPage+WAL_FRAME_HDRSIZE-1) 
        / (pWal->szPage+WAL_FRAME_HDRSIZE);
      nWalSize = MAX(nWalSize, 1);
    }

    if( walidxGetMxFrame(&pWal->hdr, iApp)>=nWalSize ){
      volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
      u32 mxFrame = walidxGetMxFrame(&pWal->hdr, !iApp);
      if( mxFrame==0 || pInfo->nBackfill ){
        rc = wal2RestartOk(pWal, iApp);
        if( rc==SQLITE_OK ){
          int iNew = !iApp;
          pWal->nCkpt++;
          walidxSetFile(&pWal->hdr, iNew);
          walidxSetMxFrame(&pWal->hdr, iNew, 0);
          sqlite3Put4byte((u8*)&pWal->hdr.aSalt[0], pWal->hdr.aFrameCksum[0]);
          sqlite3Put4byte((u8*)&pWal->hdr.aSalt[1], pWal->hdr.aFrameCksum[1]);
          walIndexWriteHdr(pWal);
          pInfo->nBackfill = 0;
          wal2RestartFinished(pWal, iApp);
          walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock));
          pWal->readLock = iNew ? WAL_LOCK_PART2_FULL1 : WAL_LOCK_PART1_FULL2;
          rc = walLockShared(pWal, WAL_READ_LOCK(pWal->readLock));
        }else if( rc==SQLITE_BUSY ){
          rc = SQLITE_OK;
        }
      }
    }
  }else if( pWal->readLock==0 ){
    int cnt;
    volatile WalCkptInfo *pInfo = walCkptInfo(pWal);
    assert( pInfo->nBackfill==pWal->hdr.mxFrame );
    if( pInfo->nBackfill>0 ){
      u32 salt1;
      sqlite3_randomness(4, &salt1);
      rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      if( rc==SQLITE_OK ){
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866

3867
3868
3869
3870
3871
3872
3873
        walRestartHdr(pWal, salt1);
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      }else if( rc!=SQLITE_BUSY ){
        return rc;
      }
    }
    walUnlockShared(pWal, WAL_READ_LOCK(0));
    pWal->readLock = -1;
    cnt = 0;
    do{
      int notUsed;
      rc = walTryBeginRead(pWal, &notUsed, 1, &cnt);
    }while( rc==WAL_RETRY );
    assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
    testcase( (rc&0xff)==SQLITE_IOERR );
    testcase( rc==SQLITE_PROTOCOL );
    testcase( rc==SQLITE_OK );
  }

  return rc;
}

/*
** Information about the current state of the WAL file and where
** the next fsync should occur - passed from sqlite3WalFrames() into
** walWriteToLog().







|










>







4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
        walRestartHdr(pWal, salt1);
        walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
      }else if( rc!=SQLITE_BUSY ){
        return rc;
      }
    }
    walUnlockShared(pWal, WAL_READ_LOCK(0));
    pWal->readLock = WAL_LOCK_NONE;
    cnt = 0;
    do{
      int notUsed;
      rc = walTryBeginRead(pWal, &notUsed, 1, &cnt);
    }while( rc==WAL_RETRY );
    assert( (rc&0xff)!=SQLITE_BUSY ); /* BUSY not possible when useWal==1 */
    testcase( (rc&0xff)==SQLITE_IOERR );
    testcase( rc==SQLITE_PROTOCOL );
    testcase( rc==SQLITE_OK );
  }

  return rc;
}

/*
** Information about the current state of the WAL file and where
** the next fsync should occur - passed from sqlite3WalFrames() into
** walWriteToLog().
3918
3919
3920
3921
3922
3923
3924












3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
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3945
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3949
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  PgHdr *pPage,               /* The page of the frame to be written */
  int nTruncate,              /* The commit flag.  Usually 0.  >0 for commit */
  sqlite3_int64 iOffset       /* Byte offset at which to write */
){
  int rc;                         /* Result code from subfunctions */
  void *pData;                    /* Data actually written */
  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-header in */












  pData = pPage->pData;
  walEncodeFrame(p->pWal, pPage->pgno, nTruncate, pData, aFrame);
  rc = walWriteToLog(p, aFrame, sizeof(aFrame), iOffset);
  if( rc ) return rc;
  /* Write the page data */
  rc = walWriteToLog(p, pData, p->szPage, iOffset+sizeof(aFrame));
  return rc;
}

/*
** This function is called as part of committing a transaction within which
** one or more frames have been overwritten. It updates the checksums for
** all frames written to the wal file by the current transaction starting
** with the earliest to have been overwritten.
**
** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
*/
static int walRewriteChecksums(Wal *pWal, u32 iLast){
  const int szPage = pWal->szPage;/* Database page size */
  int rc = SQLITE_OK;             /* Return code */

  u8 *aBuf;                       /* Buffer to load data from wal file into */
  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-headers in */
  u32 iRead;                      /* Next frame to read from wal file */
  i64 iCksumOff;


  aBuf = sqlite3_malloc(szPage + WAL_FRAME_HDRSIZE);
  if( aBuf==0 ) return SQLITE_NOMEM_BKPT;

  /* Find the checksum values to use as input for the recalculating the
  ** first checksum. If the first frame is frame 1 (implying that the current
  ** transaction restarted the wal file), these values must be read from the
  ** wal-file header. Otherwise, read them from the frame header of the
  ** previous frame.  */
  assert( pWal->iReCksum>0 );
  if( pWal->iReCksum==1 ){
    iCksumOff = 24;
  }else{
    iCksumOff = walFrameOffset(pWal->iReCksum-1, szPage) + 16;
  }
  rc = sqlite3OsRead(pWal->pWalFd, aBuf, sizeof(u32)*2, iCksumOff);
  pWal->hdr.aFrameCksum[0] = sqlite3Get4byte(aBuf);
  pWal->hdr.aFrameCksum[1] = sqlite3Get4byte(&aBuf[sizeof(u32)]);

  iRead = pWal->iReCksum;
  pWal->iReCksum = 0;
  for(; rc==SQLITE_OK && iRead<=iLast; iRead++){
    i64 iOff = walFrameOffset(iRead, szPage);
    rc = sqlite3OsRead(pWal->pWalFd, aBuf, szPage+WAL_FRAME_HDRSIZE, iOff);
    if( rc==SQLITE_OK ){
      u32 iPgno, nDbSize;
      iPgno = sqlite3Get4byte(aBuf);
      nDbSize = sqlite3Get4byte(&aBuf[4]);

      walEncodeFrame(pWal, iPgno, nDbSize, &aBuf[WAL_FRAME_HDRSIZE], aFrame);
      rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOff);
    }
  }

  sqlite3_free(aBuf);
  return rc;
}








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4711
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4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
  PgHdr *pPage,               /* The page of the frame to be written */
  int nTruncate,              /* The commit flag.  Usually 0.  >0 for commit */
  sqlite3_int64 iOffset       /* Byte offset at which to write */
){
  int rc;                         /* Result code from subfunctions */
  void *pData;                    /* Data actually written */
  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-header in */

#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
  { 
    int iWal = walidxGetFile(&p->pWal->hdr);
    int iFrame = 1 + (iOffset / (WAL_FRAME_HDRSIZE + p->pWal->szPage));
    assert( p->pWal->apWalFd[iWal]==p->pFd );
    WALTRACE(("WAL%p: page %d written to frame %d of wal %d\n",
          p->pWal, (int)pPage->pgno, iFrame, iWal
    ));
  }
#endif

  pData = pPage->pData;
  walEncodeFrame(p->pWal, pPage->pgno, nTruncate, pData, aFrame);
  rc = walWriteToLog(p, aFrame, sizeof(aFrame), iOffset);
  if( rc ) return rc;
  /* Write the page data */
  rc = walWriteToLog(p, pData, p->szPage, iOffset+sizeof(aFrame));
  return rc;
}

/*
** This function is called as part of committing a transaction within which
** one or more frames have been overwritten. It updates the checksums for
** all frames written to the wal file by the current transaction starting
** with the earliest to have been overwritten.
**
** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
*/
static int walRewriteChecksums(Wal *pWal, u32 iLast){

  int rc = SQLITE_OK;             /* Return code */
  const int szPage = pWal->szPage;/* Database page size */
  u8 *aBuf;                       /* Buffer to load data from wal file into */
  u8 aFrame[WAL_FRAME_HDRSIZE];   /* Buffer to assemble frame-headers in */
  u32 iRead;                      /* Next frame to read from wal file */
  i64 iCksumOff;
  sqlite3_file *pWalFd = pWal->apWalFd[walidxGetFile(&pWal->hdr)];

  aBuf = sqlite3_malloc(szPage + WAL_FRAME_HDRSIZE);
  if( aBuf==0 ) return SQLITE_NOMEM_BKPT;

  /* Find the checksum values to use as input for the recalculating the
  ** first checksum. If the first frame is frame 1 (implying that the current
  ** transaction restarted the wal file), these values must be read from the
  ** wal-file header. Otherwise, read them from the frame header of the
  ** previous frame.  */
  assert( pWal->iReCksum>0 );
  if( pWal->iReCksum==1 ){
    iCksumOff = 24;
  }else{
    iCksumOff = walFrameOffset(pWal->iReCksum-1, szPage) + 16;
  }
  rc = sqlite3OsRead(pWalFd, aBuf, sizeof(u32)*2, iCksumOff);
  pWal->hdr.aFrameCksum[0] = sqlite3Get4byte(aBuf);
  pWal->hdr.aFrameCksum[1] = sqlite3Get4byte(&aBuf[sizeof(u32)]);

  iRead = pWal->iReCksum;
  pWal->iReCksum = 0;
  for(; rc==SQLITE_OK && iRead<=iLast; iRead++){
    i64 iOff = walFrameOffset(iRead, szPage);
    rc = sqlite3OsRead(pWalFd, aBuf, szPage+WAL_FRAME_HDRSIZE, iOff);
    if( rc==SQLITE_OK ){
      u32 iPgno, nDbSize;
      iPgno = sqlite3Get4byte(aBuf);
      nDbSize = sqlite3Get4byte(&aBuf[4]);

      walEncodeFrame(pWal, iPgno, nDbSize, &aBuf[WAL_FRAME_HDRSIZE], aFrame);
      rc = sqlite3OsWrite(pWalFd, aFrame, sizeof(aFrame), iOff);
    }
  }

  sqlite3_free(aBuf);
  return rc;
}

4002
4003
4004
4005
4006
4007
4008


4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
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4024
4025

4026
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4033
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4039



4040







4041

4042
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4047












4048
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4088
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4094
4095
4096
4097
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4099
4100
4101
4102
4103



4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
  PgHdr *pLast = 0;               /* Last frame in list */
  int nExtra = 0;                 /* Number of extra copies of last page */
  int szFrame;                    /* The size of a single frame */
  i64 iOffset;                    /* Next byte to write in WAL file */
  WalWriter w;                    /* The writer */
  u32 iFirst = 0;                 /* First frame that may be overwritten */
  WalIndexHdr *pLive;             /* Pointer to shared header */



  assert( pList );
  assert( pWal->writeLock );

  /* If this frame set completes a transaction, then nTruncate>0.  If
  ** nTruncate==0 then this frame set does not complete the transaction. */
  assert( (isCommit!=0)==(nTruncate!=0) );

#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
  { int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
    WALTRACE(("WAL%p: frame write begin. %d frames. mxFrame=%d. %s\n",
              pWal, cnt, pWal->hdr.mxFrame, isCommit ? "Commit" : "Spill"));
  }
#endif

  pLive = (WalIndexHdr*)walIndexHdr(pWal);
  if( memcmp(&pWal->hdr, (void *)pLive, sizeof(WalIndexHdr))!=0 ){

    iFirst = pLive->mxFrame+1;
  }

  /* See if it is possible to write these frames into the start of the
  ** log file, instead of appending to it at pWal->hdr.mxFrame.
  */
  if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
    return rc;
  }

  /* If this is the first frame written into the log, write the WAL
  ** header to the start of the WAL file. See comments at the top of
  ** this source file for a description of the WAL header format.
  */



  iFrame = pWal->hdr.mxFrame;







  if( iFrame==0 ){

    u8 aWalHdr[WAL_HDRSIZE];      /* Buffer to assemble wal-header in */
    u32 aCksum[2];                /* Checksum for wal-header */

    sqlite3Put4byte(&aWalHdr[0], (WAL_MAGIC | SQLITE_BIGENDIAN));
    sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION);
    sqlite3Put4byte(&aWalHdr[8], szPage);












    sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
    if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt);
    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);

    pWal->szPage = szPage;
    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
    pWal->hdr.aFrameCksum[0] = aCksum[0];
    pWal->hdr.aFrameCksum[1] = aCksum[1];
    pWal->truncateOnCommit = 1;

    rc = sqlite3OsWrite(pWal->pWalFd, aWalHdr, sizeof(aWalHdr), 0);
    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* Sync the header (unless SQLITE_IOCAP_SEQUENTIAL is true or unless
    ** all syncing is turned off by PRAGMA synchronous=OFF).  Otherwise
    ** an out-of-order write following a WAL restart could result in
    ** database corruption.  See the ticket:
    **
    **     https://sqlite.org/src/info/ff5be73dee
    */
    if( pWal->syncHeader ){
      rc = sqlite3OsSync(pWal->pWalFd, CKPT_SYNC_FLAGS(sync_flags));
      if( rc ) return rc;
    }
  }
  if( (int)pWal->szPage!=szPage ){
    return SQLITE_CORRUPT_BKPT;  /* TH3 test case: cov1/corrupt155.test */
  }

  /* Setup information needed to write frames into the WAL */
  w.pWal = pWal;
  w.pFd = pWal->pWalFd;
  w.iSyncPoint = 0;
  w.syncFlags = sync_flags;
  w.szPage = szPage;
  iOffset = walFrameOffset(iFrame+1, szPage);
  szFrame = szPage + WAL_FRAME_HDRSIZE;

  /* Write all frames into the log file exactly once */
  for(p=pList; p; p=p->pDirty){
    int nDbSize;   /* 0 normally.  Positive == commit flag */

    /* Check if this page has already been written into the wal file by
    ** the current transaction. If so, overwrite the existing frame and
    ** set Wal.writeLock to WAL_WRITELOCK_RECKSUM - indicating that
    ** checksums must be recomputed when the transaction is committed.  */
    if( iFirst && (p->pDirty || isCommit==0) ){
      u32 iWrite = 0;
      VVA_ONLY(rc =) walFindFrame(pWal, p->pgno, &iWrite);
      assert( rc==SQLITE_OK || iWrite==0 );



      if( iWrite>=iFirst ){
        i64 iOff = walFrameOffset(iWrite, szPage) + WAL_FRAME_HDRSIZE;
        void *pData;
        if( pWal->iReCksum==0 || iWrite<pWal->iReCksum ){
          pWal->iReCksum = iWrite;
        }
        pData = p->pData;
        rc = sqlite3OsWrite(pWal->pWalFd, pData, szPage, iOff);
        if( rc ) return rc;
        p->flags &= ~PGHDR_WAL_APPEND;
        continue;
      }
    }

    iFrame++;







>
>








<
<
<
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|







4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824







4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
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4851
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4858
4859
4860
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4864
4865
4866
4867
4868
4869
4870
4871
4872
4873

4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
  PgHdr *pLast = 0;               /* Last frame in list */
  int nExtra = 0;                 /* Number of extra copies of last page */
  int szFrame;                    /* The size of a single frame */
  i64 iOffset;                    /* Next byte to write in WAL file */
  WalWriter w;                    /* The writer */
  u32 iFirst = 0;                 /* First frame that may be overwritten */
  WalIndexHdr *pLive;             /* Pointer to shared header */
  int iApp;
  int bWal2 = isWalMode2(pWal);

  assert( pList );
  assert( pWal->writeLock );

  /* If this frame set completes a transaction, then nTruncate>0.  If
  ** nTruncate==0 then this frame set does not complete the transaction. */
  assert( (isCommit!=0)==(nTruncate!=0) );








  pLive = (WalIndexHdr*)walIndexHdr(pWal);
  if( memcmp(&pWal->hdr, (void *)pLive, sizeof(WalIndexHdr))!=0 ){
    /* if( isWalMode2(pWal)==0 ) */
    iFirst = walidxGetMxFrame(pLive, walidxGetFile(pLive))+1;
  }

  /* See if it is possible to write these frames into the start of the
  ** log file, instead of appending to it at pWal->hdr.mxFrame.
  */
  else if( SQLITE_OK!=(rc = walRestartLog(pWal)) ){
    return rc;
  }

  /* If this is the first frame written into the log, write the WAL
  ** header to the start of the WAL file. See comments at the top of
  ** this source file for a description of the WAL header format.
  */
  iApp = walidxGetFile(&pWal->hdr);
  iFrame = walidxGetMxFrame(&pWal->hdr, iApp);
  assert( iApp==0 || bWal2 );

#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
  { int cnt; for(cnt=0, p=pList; p; p=p->pDirty, cnt++){}
    WALTRACE(("WAL%p: frame write begin. %d frames. iWal=%d. mxFrame=%d. %s\n",
              pWal, cnt, iApp, iFrame, isCommit ? "Commit" : "Spill"));
  }
#endif

  if( iFrame==0 ){
    u32 iCkpt = 0;
    u8 aWalHdr[WAL_HDRSIZE];      /* Buffer to assemble wal-header in */
    u32 aCksum[2];                /* Checksum for wal-header */

    sqlite3Put4byte(&aWalHdr[0], (WAL_MAGIC | SQLITE_BIGENDIAN));
    sqlite3Put4byte(&aWalHdr[4], pWal->hdr.iVersion);
    sqlite3Put4byte(&aWalHdr[8], szPage);
    if( bWal2 ){
      if( walidxGetMxFrame(&pWal->hdr, !iApp)>0 ){
        u8 aPrev[4];
        rc = sqlite3OsRead(pWal->apWalFd[!iApp], aPrev, 4, 12);
        if( rc!=SQLITE_OK ){
          return rc;
        }
        iCkpt = (sqlite3Get4byte(aPrev) + 1) & 0x0F;
      }
    }else{
      iCkpt = pWal->nCkpt;
    }
    sqlite3Put4byte(&aWalHdr[12], iCkpt);

    memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
    walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
    sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
    sqlite3Put4byte(&aWalHdr[28], aCksum[1]);

    pWal->szPage = szPage;
    pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
    pWal->hdr.aFrameCksum[0] = aCksum[0];
    pWal->hdr.aFrameCksum[1] = aCksum[1];
    pWal->truncateOnCommit = 1;

    rc = sqlite3OsWrite(pWal->apWalFd[iApp], aWalHdr, sizeof(aWalHdr), 0);
    WALTRACE(("WAL%p: wal-header write %s\n", pWal, rc ? "failed" : "ok"));
    if( rc!=SQLITE_OK ){
      return rc;
    }

    /* Sync the header (unless SQLITE_IOCAP_SEQUENTIAL is true or unless
    ** all syncing is turned off by PRAGMA synchronous=OFF).  Otherwise
    ** an out-of-order write following a WAL restart could result in
    ** database corruption.  See the ticket:
    **
    **     https://sqlite.org/src/info/ff5be73dee
    */
    if( pWal->syncHeader ){
      rc = sqlite3OsSync(pWal->apWalFd[iApp], CKPT_SYNC_FLAGS(sync_flags));
      if( rc ) return rc;
    }
  }
  if( (int)pWal->szPage!=szPage ){
    return SQLITE_CORRUPT_BKPT;  /* TH3 test case: cov1/corrupt155.test */
  }

  /* Setup information needed to write frames into the WAL */
  w.pWal = pWal;
  w.pFd = pWal->apWalFd[iApp];
  w.iSyncPoint = 0;
  w.syncFlags = sync_flags;
  w.szPage = szPage;
  iOffset = walFrameOffset(iFrame+1, szPage);
  szFrame = szPage + WAL_FRAME_HDRSIZE;

  /* Write all frames into the log file exactly once */
  for(p=pList; p; p=p->pDirty){
    int nDbSize;   /* 0 normally.  Positive == commit flag */

    /* Check if this page has already been written into the wal file by
    ** the current transaction. If so, overwrite the existing frame and
    ** set Wal.writeLock to WAL_WRITELOCK_RECKSUM - indicating that
    ** checksums must be recomputed when the transaction is committed.  */
    if( iFirst && (p->pDirty || isCommit==0) ){
      u32 iWrite = 0;
      VVA_ONLY(rc =) walSearchWal(pWal, iApp, p->pgno, &iWrite);
      assert( rc==SQLITE_OK || iWrite==0 );
      if( iWrite && bWal2 ){
        walExternalDecode(iWrite, &iWrite);
      }
      if( iWrite>=iFirst ){
        i64 iOff = walFrameOffset(iWrite, szPage) + WAL_FRAME_HDRSIZE;
        void *pData;
        if( pWal->iReCksum==0 || iWrite<pWal->iReCksum ){
          pWal->iReCksum = iWrite;
        }
        pData = p->pData;
        rc = sqlite3OsWrite(pWal->apWalFd[iApp], pData, szPage, iOff);
        if( rc ) return rc;
        p->flags &= ~PGHDR_WAL_APPEND;
        continue;
      }
    }

    iFrame++;
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
  ** boundary is crossed.  Only the part of the WAL prior to the last
  ** sector boundary is synced; the part of the last frame that extends
  ** past the sector boundary is written after the sync.
  */
  if( isCommit && WAL_SYNC_FLAGS(sync_flags)!=0 ){
    int bSync = 1;
    if( pWal->padToSectorBoundary ){
      int sectorSize = sqlite3SectorSize(pWal->pWalFd);
      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;
      bSync = (w.iSyncPoint==iOffset);
      testcase( bSync );
      while( iOffset<w.iSyncPoint ){
        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
        if( rc ) return rc;
        iOffset += szFrame;







|







4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
  ** boundary is crossed.  Only the part of the WAL prior to the last
  ** sector boundary is synced; the part of the last frame that extends
  ** past the sector boundary is written after the sync.
  */
  if( isCommit && WAL_SYNC_FLAGS(sync_flags)!=0 ){
    int bSync = 1;
    if( pWal->padToSectorBoundary ){
      int sectorSize = sqlite3SectorSize(w.pFd);
      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;
      bSync = (w.iSyncPoint==iOffset);
      testcase( bSync );
      while( iOffset<w.iSyncPoint ){
        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
        if( rc ) return rc;
        iOffset += szFrame;
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212









4213

4214
4215
4216
4217
4218
4219

4220
4221
4222
4223
4224
4225
4226
  }

  /* Append data to the wal-index. It is not necessary to lock the
  ** wal-index to do this as the SQLITE_SHM_WRITE lock held on the wal-index
  ** guarantees that there are no other writers, and no data that may
  ** be in use by existing readers is being overwritten.
  */
  iFrame = pWal->hdr.mxFrame;
  for(p=pList; p && rc==SQLITE_OK; p=p->pDirty){
    if( (p->flags & PGHDR_WAL_APPEND)==0 ) continue;
    iFrame++;
    rc = walIndexAppend(pWal, iFrame, p->pgno);
  }
  assert( pLast!=0 || nExtra==0 );
  while( rc==SQLITE_OK && nExtra>0 ){
    iFrame++;
    nExtra--;
    rc = walIndexAppend(pWal, iFrame, pLast->pgno);
  }

  if( rc==SQLITE_OK ){
    /* Update the private copy of the header. */
    pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
    testcase( szPage<=32768 );
    testcase( szPage>=65536 );
    pWal->hdr.mxFrame = iFrame;
    if( isCommit ){
      pWal->hdr.iChange++;
      pWal->hdr.nPage = nTruncate;
    }
    /* If this is a commit, update the wal-index header too. */
    if( isCommit ){
      walIndexWriteHdr(pWal);









      pWal->iCallback = iFrame;

    }
  }

  WALTRACE(("WAL%p: frame write %s\n", pWal, rc ? "failed" : "ok"));
  return rc;
}


/* 
** Write a set of frames to the log. The caller must hold the write-lock
** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
**
** The difference between this function and walFrames() is that this
** function wraps walFrames() in an SEH_TRY{...} block.







|



|





|







|







>
>
>
>
>
>
>
>
>
|
>






>







5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
  }

  /* Append data to the wal-index. It is not necessary to lock the
  ** wal-index to do this as the SQLITE_SHM_WRITE lock held on the wal-index
  ** guarantees that there are no other writers, and no data that may
  ** be in use by existing readers is being overwritten.
  */
  iFrame = walidxGetMxFrame(&pWal->hdr, iApp);
  for(p=pList; p && rc==SQLITE_OK; p=p->pDirty){
    if( (p->flags & PGHDR_WAL_APPEND)==0 ) continue;
    iFrame++;
    rc = walIndexAppend(pWal, iApp, iFrame, p->pgno);
  }
  assert( pLast!=0 || nExtra==0 );
  while( rc==SQLITE_OK && nExtra>0 ){
    iFrame++;
    nExtra--;
    rc = walIndexAppend(pWal, iApp, iFrame, pLast->pgno);
  }

  if( rc==SQLITE_OK ){
    /* Update the private copy of the header. */
    pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));
    testcase( szPage<=32768 );
    testcase( szPage>=65536 );
    walidxSetMxFrame(&pWal->hdr, iApp, iFrame);
    if( isCommit ){
      pWal->hdr.iChange++;
      pWal->hdr.nPage = nTruncate;
    }
    /* If this is a commit, update the wal-index header too. */
    if( isCommit ){
      walIndexWriteHdr(pWal);
      if( bWal2 ){
        int iOther = !walidxGetFile(&pWal->hdr);
        if( walidxGetMxFrame(&pWal->hdr, iOther) 
            && !walCkptInfo(pWal)->nBackfill 
        ){
          pWal->iCallback = walidxGetMxFrame(&pWal->hdr, 0);
          pWal->iCallback += walidxGetMxFrame(&pWal->hdr, 1);
        }
      }else{
        pWal->iCallback = iFrame;
      }
    }
  }

  WALTRACE(("WAL%p: frame write %s\n", pWal, rc ? "failed" : "ok"));
  return rc;
}


/* 
** Write a set of frames to the log. The caller must hold the write-lock
** on the log file (obtained using sqlite3WalBeginWriteTransaction()).
**
** The difference between this function and walFrames() is that this
** function wraps walFrames() in an SEH_TRY{...} block.
4332
4333
4334
4335
4336
4337
4338


4339


4340
4341
4342
4343
4344
4345
4346
4347



4348


4349








4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361




4362
4363
4364
4365
4366
4367
4368
      if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
        sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
      }
    }
  
    /* Copy data from the log to the database file. */
    if( rc==SQLITE_OK ){


      if( pWal->hdr.mxFrame && walPagesize(pWal)!=nBuf ){


        rc = SQLITE_CORRUPT_BKPT;
      }else{
        rc = walCheckpoint(pWal, db, eMode2, xBusy2, pBusyArg, sync_flags,zBuf);
      }

      /* If no error occurred, set the output variables. */
      if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
        if( pnLog ) *pnLog = (int)pWal->hdr.mxFrame;



        SEH_INJECT_FAULT;


        if( pnCkpt ) *pnCkpt = (int)(walCkptInfo(pWal)->nBackfill);








      }
    }
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )

  if( isChanged ){
    /* If a new wal-index header was loaded before the checkpoint was
    ** performed, then the pager-cache associated with pWal is now
    ** out of date. So zero the cached wal-index header to ensure that
    ** next time the pager opens a snapshot on this database it knows that
    ** the cache needs to be reset.
    */




    memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
  }

  walDisableBlocking(pWal);
  sqlite3WalDb(pWal, 0);

  /* Release the locks. */







>
>
|
>
>




|


|
>
>
>

>
>
|
>
>
>
>
>
>
>
>





|





|
>
>
>
>







5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
      if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
        sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
      }
    }
  
    /* Copy data from the log to the database file. */
    if( rc==SQLITE_OK ){
      int iCkpt = walidxGetFile(&pWal->hdr);
  
      if( (walPagesize(pWal)!=nBuf) 
       && ((pWal->hdr.mxFrame2 & 0x7FFFFFFF) || pWal->hdr.mxFrame)
      ){
        rc = SQLITE_CORRUPT_BKPT;
      }else{
        rc = walCheckpoint(pWal, db, eMode2, xBusy2, pBusyArg, sync_flags,zBuf);
      }
  
      /* If no error occurred, set the output variables. */
      if( rc==SQLITE_OK || rc==SQLITE_BUSY ){
        if( pnLog ){
          WalIndexHdr *pHdr = &pWal->hdr;
          *pnLog = walidxGetMxFrame(pHdr, 0) + walidxGetMxFrame(pHdr, 1);
        }
        SEH_INJECT_FAULT;
        if( pnCkpt ){
          if( isWalMode2(pWal) ){
            if( (int)(walCkptInfo(pWal)->nBackfill) ){
              *pnCkpt = walidxGetMxFrame(&pWal->hdr, iCkpt);
            }else{
              *pnCkpt = 0;
            }
          }else{
            *pnCkpt = walCkptInfo(pWal)->nBackfill;
          }
        }
      }
    }
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )

  if( isChanged && pWal->bClosing==0 ){
    /* If a new wal-index header was loaded before the checkpoint was
    ** performed, then the pager-cache associated with pWal is now
    ** out of date. So zero the cached wal-index header to ensure that
    ** next time the pager opens a snapshot on this database it knows that
    ** the cache needs to be reset.
    **
    ** Except, do not do this if the wal is being closed. In this case
    ** the caller needs the wal-index header to check if the database is
    ** in wal2 mode and the "other" wal file also needs to be checkpointed.
    ** Besides, the pager cache will not be used again in this case. */
    memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
  }

  walDisableBlocking(pWal);
  sqlite3WalDb(pWal, 0);

  /* Release the locks. */
4414
4415
4416
4417
4418
4419
4420

4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438

4439
4440
4441
4442
4443
4444
4445
** If op is negative, then do a dry-run of the op==1 case but do
** not actually change anything. The pager uses this to see if it
** should acquire the database exclusive lock prior to invoking
** the op==1 case.
*/
int sqlite3WalExclusiveMode(Wal *pWal, int op){
  int rc;

  assert( pWal->writeLock==0 );
  assert( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE || op==-1 );

  /* pWal->readLock is usually set, but might be -1 if there was a
  ** prior error while attempting to acquire are read-lock. This cannot
  ** happen if the connection is actually in exclusive mode (as no xShmLock
  ** locks are taken in this case). Nor should the pager attempt to
  ** upgrade to exclusive-mode following such an error.
  */
#ifndef SQLITE_USE_SEH
  assert( pWal->readLock>=0 || pWal->lockError );
#endif
  assert( pWal->readLock>=0 || (op<=0 && pWal->exclusiveMode==0) );

  if( op==0 ){
    if( pWal->exclusiveMode!=WAL_NORMAL_MODE ){
      pWal->exclusiveMode = WAL_NORMAL_MODE;
      if( walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK ){

        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = pWal->exclusiveMode==WAL_NORMAL_MODE;
    }else{
      /* Already in locking_mode=NORMAL */
      rc = 0;
    }







>










|

|


|

|
>







5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
** If op is negative, then do a dry-run of the op==1 case but do
** not actually change anything. The pager uses this to see if it
** should acquire the database exclusive lock prior to invoking
** the op==1 case.
*/
int sqlite3WalExclusiveMode(Wal *pWal, int op){
  int rc;

  assert( pWal->writeLock==0 );
  assert( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE || op==-1 );

  /* pWal->readLock is usually set, but might be -1 if there was a
  ** prior error while attempting to acquire are read-lock. This cannot
  ** happen if the connection is actually in exclusive mode (as no xShmLock
  ** locks are taken in this case). Nor should the pager attempt to
  ** upgrade to exclusive-mode following such an error.
  */
#ifndef SQLITE_USE_SEH
  assert( pWal->readLock!=WAL_LOCK_NONE || pWal->lockError );
#endif
  assert( pWal->readLock!=WAL_LOCK_NONE || (op<=0 && pWal->exclusiveMode==0) );

  if( op==0 ){
    if( pWal->exclusiveMode ){
      pWal->exclusiveMode = WAL_NORMAL_MODE;
      rc = walLockShared(pWal, WAL_READ_LOCK(pWal->readLock));
      if( rc!=SQLITE_OK ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = pWal->exclusiveMode==WAL_NORMAL_MODE;
    }else{
      /* Already in locking_mode=NORMAL */
      rc = 0;
    }
4469
4470
4471
4472
4473
4474
4475



4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
** every other subsystem, so the WAL module can put whatever it needs
** in the object.
*/
int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
  int rc = SQLITE_OK;
  WalIndexHdr *pRet;
  static const u32 aZero[4] = { 0, 0, 0, 0 };




  assert( pWal->readLock>=0 && pWal->writeLock==0 );

  if( memcmp(&pWal->hdr.aFrameCksum[0],aZero,16)==0 ){
    *ppSnapshot = 0;
    return SQLITE_ERROR;
  }
  pRet = (WalIndexHdr*)sqlite3_malloc(sizeof(WalIndexHdr));
  if( pRet==0 ){
    rc = SQLITE_NOMEM_BKPT;
  }else{







>
>
>



|







5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
** every other subsystem, so the WAL module can put whatever it needs
** in the object.
*/
int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
  int rc = SQLITE_OK;
  WalIndexHdr *pRet;
  static const u32 aZero[4] = { 0, 0, 0, 0 };

  /* Snapshots may not be used with wal2 mode databases. */
  if( isWalMode2(pWal) ) return SQLITE_ERROR;

  assert( pWal->readLock>=0 && pWal->writeLock==0 );

  if( memcmp(&pWal->hdr.aFrameCksum[0],aZero,8)==0 ){
    *ppSnapshot = 0;
    return SQLITE_ERROR;
  }
  pRet = (WalIndexHdr*)sqlite3_malloc(sizeof(WalIndexHdr));
  if( pRet==0 ){
    rc = SQLITE_NOMEM_BKPT;
  }else{
4526
4527
4528
4529
4530
4531
4532




4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
** lock is released before returning.
*/
int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot){
  int rc;




  SEH_TRY {
    rc = walLockShared(pWal, WAL_CKPT_LOCK);
    if( rc==SQLITE_OK ){
      WalIndexHdr *pNew = (WalIndexHdr*)pSnapshot;
      if( memcmp(pNew->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
       || pNew->mxFrame<walCkptInfo(pWal)->nBackfillAttempted
      ){
        rc = SQLITE_ERROR_SNAPSHOT;
        walUnlockShared(pWal, WAL_CKPT_LOCK);
      }
    }
  }
  SEH_EXCEPT( rc = walHandleException(pWal); )
  return rc;
}

/*
** Release a lock obtained by an earlier successful call to
** sqlite3WalSnapshotCheck().
*/







>
>
>
>












|







5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
** If the snapshot is not available, SQLITE_ERROR is returned. Or, if
** the CHECKPOINTER lock cannot be obtained, SQLITE_BUSY. If any error
** occurs (any value other than SQLITE_OK is returned), the CHECKPOINTER
** lock is released before returning.
*/
int sqlite3WalSnapshotCheck(Wal *pWal, sqlite3_snapshot *pSnapshot){
  int rc;

  /* Snapshots may not be used with wal2 mode databases. */
  if( isWalMode2(pWal) ) return SQLITE_ERROR;

  SEH_TRY {
    rc = walLockShared(pWal, WAL_CKPT_LOCK);
    if( rc==SQLITE_OK ){
      WalIndexHdr *pNew = (WalIndexHdr*)pSnapshot;
      if( memcmp(pNew->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
       || pNew->mxFrame<walCkptInfo(pWal)->nBackfillAttempted
      ){
        rc = SQLITE_ERROR_SNAPSHOT;
        walUnlockShared(pWal, WAL_CKPT_LOCK);
      }
    }
  }
  SEH_EXCEPT( rc = walHandleException(pWal) );
  return rc;
}

/*
** Release a lock obtained by an earlier successful call to
** sqlite3WalSnapshotCheck().
*/
4569
4570
4571
4572
4573
4574
4575
4576








4577
4578
4579
  return (pWal ? pWal->szPage : 0);
}
#endif

/* Return the sqlite3_file object for the WAL file
*/
sqlite3_file *sqlite3WalFile(Wal *pWal){
  return pWal->pWalFd;








}

#endif /* #ifndef SQLITE_OMIT_WAL */







|
>
>
>
>
>
>
>
>



5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
  return (pWal ? pWal->szPage : 0);
}
#endif

/* Return the sqlite3_file object for the WAL file
*/
sqlite3_file *sqlite3WalFile(Wal *pWal){
  return pWal->apWalFd[0];
}

/* 
** Return the journal mode used by this Wal object.
*/
int sqlite3WalJournalMode(Wal *pWal){
  assert( pWal );
  return (isWalMode2(pWal) ? PAGER_JOURNALMODE_WAL2 : PAGER_JOURNALMODE_WAL);
}

#endif /* #ifndef SQLITE_OMIT_WAL */

Changes to src/wal.h.

22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47

48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
/* Macros for extracting appropriate sync flags for either transaction
** commits (WAL_SYNC_FLAGS(X)) or for checkpoint ops (CKPT_SYNC_FLAGS(X)):
*/
#define WAL_SYNC_FLAGS(X)   ((X)&0x03)
#define CKPT_SYNC_FLAGS(X)  (((X)>>2)&0x03)

#ifdef SQLITE_OMIT_WAL
# define sqlite3WalOpen(x,y,z)                   0
# define sqlite3WalLimit(x,y)
# define sqlite3WalClose(v,w,x,y,z)              0
# define sqlite3WalBeginReadTransaction(y,z)     0
# define sqlite3WalEndReadTransaction(z)
# define sqlite3WalDbsize(y)                     0
# define sqlite3WalBeginWriteTransaction(y)      0
# define sqlite3WalEndWriteTransaction(x)        0
# define sqlite3WalUndo(x,y,z)                   0
# define sqlite3WalSavepoint(y,z)
# define sqlite3WalSavepointUndo(y,z)            0
# define sqlite3WalFrames(u,v,w,x,y,z)           0
# define sqlite3WalCheckpoint(q,r,s,t,u,v,w,x,y,z) 0
# define sqlite3WalCallback(z)                   0
# define sqlite3WalExclusiveMode(y,z)            0
# define sqlite3WalHeapMemory(z)                 0
# define sqlite3WalFramesize(z)                  0
# define sqlite3WalFindFrame(x,y,z)              0
# define sqlite3WalFile(x)                       0

# undef SQLITE_USE_SEH
#else

#define WAL_SAVEPOINT_NDATA 4

/* Connection to a write-ahead log (WAL) file. 
** There is one object of this type for each pager. 
*/
typedef struct Wal Wal;

/* Open and close a connection to a write-ahead log. */
int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *, int, i64, Wal**);
int sqlite3WalClose(Wal *pWal, sqlite3*, int sync_flags, int, u8 *);

/* Set the limiting size of a WAL file. */
void sqlite3WalLimit(Wal*, i64);

/* Used by readers to open (lock) and close (unlock) a snapshot.  A 
** snapshot is like a read-transaction.  It is the state of the database







|


















>











|







22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
/* Macros for extracting appropriate sync flags for either transaction
** commits (WAL_SYNC_FLAGS(X)) or for checkpoint ops (CKPT_SYNC_FLAGS(X)):
*/
#define WAL_SYNC_FLAGS(X)   ((X)&0x03)
#define CKPT_SYNC_FLAGS(X)  (((X)>>2)&0x03)

#ifdef SQLITE_OMIT_WAL
# define sqlite3WalOpen(w,x,y,z)                 0
# define sqlite3WalLimit(x,y)
# define sqlite3WalClose(v,w,x,y,z)              0
# define sqlite3WalBeginReadTransaction(y,z)     0
# define sqlite3WalEndReadTransaction(z)
# define sqlite3WalDbsize(y)                     0
# define sqlite3WalBeginWriteTransaction(y)      0
# define sqlite3WalEndWriteTransaction(x)        0
# define sqlite3WalUndo(x,y,z)                   0
# define sqlite3WalSavepoint(y,z)
# define sqlite3WalSavepointUndo(y,z)            0
# define sqlite3WalFrames(u,v,w,x,y,z)           0
# define sqlite3WalCheckpoint(q,r,s,t,u,v,w,x,y,z) 0
# define sqlite3WalCallback(z)                   0
# define sqlite3WalExclusiveMode(y,z)            0
# define sqlite3WalHeapMemory(z)                 0
# define sqlite3WalFramesize(z)                  0
# define sqlite3WalFindFrame(x,y,z)              0
# define sqlite3WalFile(x)                       0
# define sqlite3WalJournalMode(x)                0
# undef SQLITE_USE_SEH
#else

#define WAL_SAVEPOINT_NDATA 4

/* Connection to a write-ahead log (WAL) file. 
** There is one object of this type for each pager. 
*/
typedef struct Wal Wal;

/* Open and close a connection to a write-ahead log. */
int sqlite3WalOpen(sqlite3_vfs*, sqlite3_file*, const char *,int,i64,int,Wal**);
int sqlite3WalClose(Wal *pWal, sqlite3*, int sync_flags, int, u8 *);

/* Set the limiting size of a WAL file. */
void sqlite3WalLimit(Wal*, i64);

/* Used by readers to open (lock) and close (unlock) a snapshot.  A 
** snapshot is like a read-transaction.  It is the state of the database
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** stored in each frame (i.e. the db page-size when the WAL was created).
*/
int sqlite3WalFramesize(Wal *pWal);
#endif

/* Return the sqlite3_file object for the WAL file */
sqlite3_file *sqlite3WalFile(Wal *pWal);




#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
int sqlite3WalWriteLock(Wal *pWal, int bLock);
void sqlite3WalDb(Wal *pWal, sqlite3 *db);
#endif

#ifdef SQLITE_USE_SEH
int sqlite3WalSystemErrno(Wal*);
#endif

#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* SQLITE_WAL_H */







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** stored in each frame (i.e. the db page-size when the WAL was created).
*/
int sqlite3WalFramesize(Wal *pWal);
#endif

/* Return the sqlite3_file object for the WAL file */
sqlite3_file *sqlite3WalFile(Wal *pWal);

/* Return the journal mode (WAL or WAL2) used by this Wal object. */
int sqlite3WalJournalMode(Wal *pWal);

#ifdef SQLITE_ENABLE_SETLK_TIMEOUT
int sqlite3WalWriteLock(Wal *pWal, int bLock);
void sqlite3WalDb(Wal *pWal, sqlite3 *db);
#endif

#ifdef SQLITE_USE_SEH
int sqlite3WalSystemErrno(Wal*);
#endif

#endif /* ifndef SQLITE_OMIT_WAL */
#endif /* SQLITE_WAL_H */

Changes to test/corruptA.test.

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# Corrupt the file header in various ways and make sure the corruption
# is detected when opening the database file.
#
db close
forcecopy test.db test.db-template

set unreadable_version 02
ifcapable wal { set unreadable_version 03 }
do_test corruptA-2.1 {
  forcecopy test.db-template test.db
  hexio_write test.db 19 $unreadable_version   ;# the read format number
  sqlite3 db test.db
  catchsql {SELECT * FROM t1}  
} {1 {file is not a database}}
 







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# Corrupt the file header in various ways and make sure the corruption
# is detected when opening the database file.
#
db close
forcecopy test.db test.db-template

set unreadable_version 02
ifcapable wal { set unreadable_version 04 }
do_test corruptA-2.1 {
  forcecopy test.db-template test.db
  hexio_write test.db 19 $unreadable_version   ;# the read format number
  sqlite3 db test.db
  catchsql {SELECT * FROM t1}  
} {1 {file is not a database}}
 

Changes to test/permutations.test.

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# Define the coverage related test suites:
#
#   coverage-wal
#
test_suite "coverage-wal" -description {
  Coverage tests for file wal.c.
} -files {


  wal.test wal2.test wal3.test wal4.test wal5.test
  wal64k.test wal6.test wal7.test wal8.test wal9.test
  walbak.test walbig.test walblock.test walcksum.test walcrash2.test
  walcrash3.test walcrash4.test walcrash.test walfault.test walhook.test
  walmode.test walnoshm.test waloverwrite.test walpersist.test 
  walprotocol2.test walprotocol.test walro2.test walrofault.test 
  walro.test walshared.test walslow.test walvfs.test
  walfault2.test
  nockpt.test

  snapshot2.test snapshot3.test snapshot4.test
  snapshot_fault.test snapshot.test snapshot_up.test


} 

test_suite "coverage-pager" -description {
  Coverage tests for file pager.c.
} -files {
  pager1.test    pager2.test  pagerfault.test  pagerfault2.test
  walfault.test  walbak.test  journal2.test    tkt-9d68c883.test







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# Define the coverage related test suites:
#
#   coverage-wal
#
test_suite "coverage-wal" -description {
  Coverage tests for file wal.c.
} -files {
  wal2big.test wal2recover.test wal2rewrite.test
  wal2simple.test wal2snapshot.test wal2.test
  wal3.test wal4.test wal5.test
  wal64k.test wal6.test wal7.test wal8.test wal9.test
  walbak.test walbig.test walblock.test walcksum.test 
  walfault.test walhook.test walmode.test walnoshm.test
  waloverwrite.test walpersist.test walprotocol2.test
  walprotocol.test walro2.test walrofault.test walro.test
  walshared.test walslow.test wal.test
  wal2savepoint.test wal2lock.test wal2recover2.test
  walvfs.test walfault2.test nockpt.test

  snapshot2.test snapshot3.test snapshot4.test
  snapshot_fault.test snapshot.test snapshot_up.test
  walcrash2.test walcrash3.test walcrash4.test walcrash.test
  wal2fault.test
} 

test_suite "coverage-pager" -description {
  Coverage tests for file pager.c.
} -files {
  pager1.test    pager2.test  pagerfault.test  pagerfault2.test
  walfault.test  walbak.test  journal2.test    tkt-9d68c883.test
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    insert.test   insert2.test  insert3.test rollback.test 
    select1.test  select2.test  select3.test
  }
}

test_suite "wal" -description {
  Run tests with journal_mode=WAL

















} -initialize {
  set ::G(savepoint6_iterations) 100
} -shutdown {
  unset -nocomplain ::G(savepoint6_iterations)
} -files {
  savepoint.test     savepoint2.test     savepoint6.test
  trans.test         avtrans.test







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    insert.test   insert2.test  insert3.test rollback.test 
    select1.test  select2.test  select3.test
  }
}

test_suite "wal" -description {
  Run tests with journal_mode=WAL
} -initialize {
  set ::G(savepoint6_iterations) 100
} -shutdown {
  unset -nocomplain ::G(savepoint6_iterations)
} -files {
  savepoint.test     savepoint2.test     savepoint6.test
  trans.test         avtrans.test

  fts3aa.test  fts3ab.test  fts3ac.test  fts3ad.test
  fts3ae.test  fts3af.test  fts3ag.test  fts3ah.test
  fts3ai.test  fts3aj.test  fts3ak.test  fts3al.test
  fts3am.test  fts3an.test  fts3ao.test  fts3b.test
  fts3c.test   fts3d.test   fts3e.test   fts3query.test 
}

test_suite "wal2" -description {
  Run tests with journal_mode=WAL2
} -initialize {
  set ::G(savepoint6_iterations) 100
} -shutdown {
  unset -nocomplain ::G(savepoint6_iterations)
} -files {
  savepoint.test     savepoint2.test     savepoint6.test
  trans.test         avtrans.test

Changes to test/rdonly.test.

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# returns 1 if the database N of connection D is read-only, 0 if it is
# read/write, or -1 if N is not the name of a database on connection D.
#
do_test rdonly-1.1.1 {
  sqlite3_db_readonly db main
} {0}

# Changes the write version from 1 to 3.  Verify that the database
# can be read but not written.
#
do_test rdonly-1.2 {
  db close
  hexio_get_int [hexio_read test.db 18 1]
} 1
do_test rdonly-1.3 {
  hexio_write test.db 18 03
  sqlite3 db test.db
  execsql {
    SELECT * FROM t1;
  }
} {1}
do_test rdonly-1.3.1 {
  sqlite3_db_readonly db main







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# returns 1 if the database N of connection D is read-only, 0 if it is
# read/write, or -1 if N is not the name of a database on connection D.
#
do_test rdonly-1.1.1 {
  sqlite3_db_readonly db main
} {0}

# Changes the write version from 1 to 4.  Verify that the database
# can be read but not written.
#
do_test rdonly-1.2 {
  db close
  hexio_get_int [hexio_read test.db 18 1]
} 1
do_test rdonly-1.3 {
  hexio_write test.db 18 04
  sqlite3 db test.db
  execsql {
    SELECT * FROM t1;
  }
} {1}
do_test rdonly-1.3.1 {
  sqlite3_db_readonly db main
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# Now, after connection [db] has loaded the database schema, modify the
# write-version of the file (and the change-counter, so that the 
# write-version is reloaded). This way, SQLite does not discover that
# the database is read-only until after it is locked.
#
set ro_version 02
ifcapable wal { set ro_version 03 }
do_test rdonly-1.6 {
  hexio_write test.db 18 $ro_version     ; # write-version
  hexio_write test.db 24 11223344        ; # change-counter
  catchsql {
    INSERT INTO t1 VALUES(2);
  }
} {1 {attempt to write a readonly database}}

finish_test







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# Now, after connection [db] has loaded the database schema, modify the
# write-version of the file (and the change-counter, so that the 
# write-version is reloaded). This way, SQLite does not discover that
# the database is read-only until after it is locked.
#
set ro_version 02
ifcapable wal { set ro_version 04 }
do_test rdonly-1.6 {
  hexio_write test.db 18 $ro_version     ; # write-version
  hexio_write test.db 24 11223344        ; # change-counter
  catchsql {
    INSERT INTO t1 VALUES(2);
  }
} {1 {attempt to write a readonly database}}

finish_test

Changes to test/savepoint.test.

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do_test savepoint-1.1 {
  wal_set_journal_mode
  execsql {
    SAVEPOINT sp1;
    RELEASE sp1;
  }
} {}

do_test savepoint-1.2 {
  execsql {
    SAVEPOINT sp1;
    ROLLBACK TO sp1;
  }
} {}
do_test savepoint-1.3 {







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do_test savepoint-1.1 {
  wal_set_journal_mode
  execsql {
    SAVEPOINT sp1;
    RELEASE sp1;
  }
} {}
wal_check_journal_mode savepoint-1.1
do_test savepoint-1.2 {
  execsql {
    SAVEPOINT sp1;
    ROLLBACK TO sp1;
  }
} {}
do_test savepoint-1.3 {
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    CREATE TABLE t3(a, b, UNIQUE(a, b));
    ROLLBACK TO one;
  }
} {}
integrity_check savepoint-11.7
do_test savepoint-11.8 {
  execsql { ROLLBACK }

  execsql { PRAGMA wal_checkpoint }
  file size test.db
} {8192}

do_test savepoint-11.9 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;







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    CREATE TABLE t3(a, b, UNIQUE(a, b));
    ROLLBACK TO one;
  }
} {}
integrity_check savepoint-11.7
do_test savepoint-11.8 {
  execsql { ROLLBACK }
  db close
  sqlite3 db test.db
  file size test.db
} {8192}

do_test savepoint-11.9 {
  execsql {
    DROP TABLE IF EXISTS t1;
    DROP TABLE IF EXISTS t2;

Changes to test/savepoint6.test.

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#
# $Id: savepoint6.test,v 1.4 2009/06/05 17:09:12 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

proc sql {zSql} {




  uplevel db eval [list $zSql]
  #puts stderr "$zSql ;"
}

set DATABASE_SCHEMA {
    PRAGMA auto_vacuum = incremental;
    CREATE TABLE t1(x, y);







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#
# $Id: savepoint6.test,v 1.4 2009/06/05 17:09:12 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

proc sql {zSql} {
  if {0 && $::debug_op} {
    puts stderr "$zSql ;"
    flush stderr
  }
  uplevel db eval [list $zSql]
  #puts stderr "$zSql ;"
}

set DATABASE_SCHEMA {
    PRAGMA auto_vacuum = incremental;
    CREATE TABLE t1(x, y);
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#   rollback  NAME
#   release   NAME
#
#   insert_rows XVALUES
#   delete_rows XVALUES
#
proc savepoint {zName} {

  catch { sql "SAVEPOINT $zName" }
  lappend ::lSavepoint [list $zName [array get ::aEntry]]
}

proc rollback {zName} {

  catch { sql "ROLLBACK TO $zName" }
  for {set i [expr {[llength $::lSavepoint]-1}]} {$i>=0} {incr i -1} {
    set zSavepoint [lindex $::lSavepoint $i 0]
    if {$zSavepoint eq $zName} {
      unset -nocomplain ::aEntry
      array set ::aEntry [lindex $::lSavepoint $i 1]


      if {$i+1 < [llength $::lSavepoint]} {
        set ::lSavepoint [lreplace $::lSavepoint [expr $i+1] end]
      }
      break
    }
  }
}

proc release {zName} {

  catch { sql "RELEASE $zName" }
  for {set i [expr {[llength $::lSavepoint]-1}]} {$i>=0} {incr i -1} {
    set zSavepoint [lindex $::lSavepoint $i 0]
    if {$zSavepoint eq $zName} {
      set ::lSavepoint [lreplace $::lSavepoint $i end]
      break
    }
  }

  if {[llength $::lSavepoint] == 0} {
    #puts stderr "-- End of transaction!!!!!!!!!!!!!"
  }
}

proc insert_rows {lX} {

  foreach x $lX {
    set y [x_to_y $x]

    # Update database [db]
    sql "INSERT OR REPLACE INTO t1 VALUES($x, '$y')"

    # Update the Tcl database.
    set ::aEntry($x) $y
  }
}

proc delete_rows {lX} {

  foreach x $lX {
    # Update database [db]
    sql "DELETE FROM t1 WHERE x = $x"

    # Update the Tcl database.
    unset -nocomplain ::aEntry($x)
  }







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#   rollback  NAME
#   release   NAME
#
#   insert_rows XVALUES
#   delete_rows XVALUES
#
proc savepoint {zName} {
  if {$::debug_op} { puts stderr "savepoint $zName" ; flush stderr }
  catch { sql "SAVEPOINT $zName" }
  lappend ::lSavepoint [list $zName [array get ::aEntry]]
}

proc rollback {zName} {
  if {$::debug_op} { puts stderr "rollback $zName" ; flush stderr }
  catch { sql "ROLLBACK TO $zName" }
  for {set i [expr {[llength $::lSavepoint]-1}]} {$i>=0} {incr i -1} {
    set zSavepoint [lindex $::lSavepoint $i 0]
    if {$zSavepoint eq $zName} {
      unset -nocomplain ::aEntry
      array set ::aEntry [lindex $::lSavepoint $i 1]


      if {$i+1 < [llength $::lSavepoint]} {
        set ::lSavepoint [lreplace $::lSavepoint [expr $i+1] end]
      }
      break
    }
  }
}

proc release {zName} {
  if {$::debug_op} { puts stderr "release $zName" ; flush stderr }
  catch { sql "RELEASE $zName" }
  for {set i [expr {[llength $::lSavepoint]-1}]} {$i>=0} {incr i -1} {
    set zSavepoint [lindex $::lSavepoint $i 0]
    if {$zSavepoint eq $zName} {
      set ::lSavepoint [lreplace $::lSavepoint $i end]
      break
    }
  }

  if {[llength $::lSavepoint] == 0} {
    #puts stderr "-- End of transaction!!!!!!!!!!!!!"
  }
}

proc insert_rows {lX} {
  if {$::debug_op} { puts stderr "insert_rows $lX" ; flush stderr }
  foreach x $lX {
    set y [x_to_y $x]

    # Update database [db]
    sql "INSERT OR REPLACE INTO t1 VALUES($x, '$y')"

    # Update the Tcl database.
    set ::aEntry($x) $y
  }
}

proc delete_rows {lX} {
  if {$::debug_op} { puts stderr "delete_rows $lX" ; flush stderr }
  foreach x $lX {
    # Update database [db]
    sql "DELETE FROM t1 WHERE x = $x"

    # Update the Tcl database.
    unset -nocomplain ::aEntry($x)
  }
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  set ret [list]
  for {set i 0} {$i<$nRes} {incr i} {
    lappend ret [expr int(rand()*$nRange)]
  }
  return $ret
} 
#-------------------------------------------------------------------------






proc database_op {} {
  set i [expr int(rand()*2)] 
  if {$i==0} {
    insert_rows [random_integers 100 1000]
  }
  if {$i==1} {







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  set ret [list]
  for {set i 0} {$i<$nRes} {incr i} {
    lappend ret [expr int(rand()*$nRange)]
  }
  return $ret
} 
#-------------------------------------------------------------------------

set ::debug_op 0
proc debug_ops {} {
  set ::debug_op 1
}

proc database_op {} {
  set i [expr int(rand()*2)] 
  if {$i==0} {
    insert_rows [random_integers 100 1000]
  }
  if {$i==1} {
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proc savepoint_op {} {
  set names {one two three four five}
  set cmds  {savepoint savepoint savepoint savepoint release rollback}

  set C [lindex $cmds [expr int(rand()*6)]]
  set N [lindex $names [expr int(rand()*5)]]

  #puts stderr "   $C $N ;  "
  #flush stderr

  $C $N
  return ok
}

expr srand(0)

############################################################################







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proc savepoint_op {} {
  set names {one two three four five}
  set cmds  {savepoint savepoint savepoint savepoint release rollback}

  set C [lindex $cmds [expr int(rand()*6)]]
  set N [lindex $names [expr int(rand()*5)]]




  $C $N
  return ok
}

expr srand(0)

############################################################################

Changes to test/tester.tcl.

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# Create a test database
#
proc reset_db {} {
  catch {db close}
  forcedelete test.db
  forcedelete test.db-journal
  forcedelete test.db-wal

  sqlite3 db ./test.db
  set ::DB [sqlite3_connection_pointer db]
  if {[info exists ::SETUP_SQL]} {
    db eval $::SETUP_SQL
  }
}
reset_db







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# Create a test database
#
proc reset_db {} {
  catch {db close}
  forcedelete test.db
  forcedelete test.db-journal
  forcedelete test.db-wal
  forcedelete test.db-wal2
  sqlite3 db ./test.db
  set ::DB [sqlite3_connection_pointer db]
  if {[info exists ::SETUP_SQL]} {
    db eval $::SETUP_SQL
  }
}
reset_db
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#     Otherwise (if not running a WAL permutation) this is a no-op.
#
#   wal_is_wal_mode
#
#     Returns true if this test should be run in WAL mode. False otherwise.
#
proc wal_is_wal_mode {} {
  expr {[permutation] eq "wal"}


}
proc wal_set_journal_mode {{db db}} {
  if { [wal_is_wal_mode] } {




    $db eval "PRAGMA journal_mode = WAL"





  }
}
proc wal_check_journal_mode {testname {db db}} {
  if { [wal_is_wal_mode] } {
    $db eval { SELECT * FROM sqlite_master }




    do_test $testname [list $db eval "PRAGMA main.journal_mode"] {wal}
  }
}

proc wal_is_capable {} {
  ifcapable !wal { return 0 }
  if {[permutation]=="journaltest"} { return 0 }
  return 1







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#     Otherwise (if not running a WAL permutation) this is a no-op.
#
#   wal_is_wal_mode
#
#     Returns true if this test should be run in WAL mode. False otherwise.
#
proc wal_is_wal_mode {} {
  if {[permutation] eq "wal"} { return 1 }
  if {[permutation] eq "wal2"} { return 2 }
  return 0
}
proc wal_set_journal_mode {{db db}} {
  switch -- [wal_is_wal_mode] {
    0 {
    }

    1 {
      $db eval "PRAGMA journal_mode = WAL"
    }

    2 {
      $db eval "PRAGMA journal_mode = WAL2"
    }
  }
}
proc wal_check_journal_mode {testname {db db}} {
  if { [wal_is_wal_mode] } {
    $db eval { SELECT * FROM sqlite_master }
    set expected "wal"
    if {[wal_is_wal_mode]==2} {
      set expected "wal2"
    }
    do_test $testname [list $db eval "PRAGMA main.journal_mode"] $expected
  }
}

proc wal_is_capable {} {
  ifcapable !wal { return 0 }
  if {[permutation]=="journaltest"} { return 0 }
  return 1

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      CREATE TABLE aux.t2(a, b);
      PRAGMA main.journal_mode = WAL;
      PRAGMA aux.journal_mode = WAL;
      INSERT INTO t1 VALUES('x', 'y');
      INSERT INTO t2 VALUES('x', 'y');
    }
    lsort [array names ::T1]
  } {test.db1 test.db1-journal test.db1-wal}
  
  do_test 5.1.2 {
    lsort [array names ::T2]
  } {test.db2 test.db2-journal test.db2-wal}
  db close
  
  tvfs1 delete
  tvfs2 delete
}

#-------------------------------------------------------------------------







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      CREATE TABLE aux.t2(a, b);
      PRAGMA main.journal_mode = WAL;
      PRAGMA aux.journal_mode = WAL;
      INSERT INTO t1 VALUES('x', 'y');
      INSERT INTO t2 VALUES('x', 'y');
    }
    lsort [array names ::T1]
  } {test.db1 test.db1-journal test.db1-wal test.db1-wal2}
  
  do_test 5.1.2 {
    lsort [array names ::T2]
  } {test.db2 test.db2-journal test.db2-wal test.db2-wal2}
  db close
  
  tvfs1 delete
  tvfs2 delete
}

#-------------------------------------------------------------------------

Changes to test/wal.test.

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  5   2048    1
  6   4096    1
  7   8192    1
  8  16384    1
  9  32768    1
 10  65536    1
 11 131072    0
 11   1016    0
} {

  if {$::SQLITE_MAX_PAGE_SIZE < $pgsz} {
    set works 0
  }

  for {set pg 1} {$pg <= 3} {incr pg} {
    forcecopy testX.db test.db
    forcedelete test.db-wal
  
    # Check that the database now exists and consists of three pages. And
    # that there is no associated wal file.
    #
    do_test wal-18.2.$tn.$pg.1 { file exists test.db-wal } 0
    do_test wal-18.2.$tn.$pg.2 { file exists test.db } 1
    do_test wal-18.2.$tn.$pg.3 { file size test.db } [expr 1024*3]
  
    do_test wal-18.2.$tn.$pg.4 {

      # Create a wal file that contains a single frame (database page
      # number $pg) with the commit flag set. The frame checksum is
      # correct, but the contents of the database page are corrupt.
      #
      # The page-size in the log file header is set to $pgsz. If the







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  5   2048    1
  6   4096    1
  7   8192    1
  8  16384    1
  9  32768    1
 10  65536    1
 11 131072    0
 12   1016    0
} {

  if {$::SQLITE_MAX_PAGE_SIZE < $pgsz} {
    set works 0
  }

  for {set pg 1} {$pg <= 3} {incr pg} {
    forcecopy testX.db test.db
    forcedelete test.db-wal

    # Check that the database now exists and consists of three pages. And
    # that there is no associated wal file.
    #
    do_test wal-18.2.$tn.$pg.1 { file exists test.db-wal } 0
    do_test wal-18.2.$tn.$pg.2 { file exists test.db } 1
    do_test wal-18.2.$tn.$pg.3 { file size test.db } [expr 1024*3]

    do_test wal-18.2.$tn.$pg.4 {

      # Create a wal file that contains a single frame (database page
      # number $pg) with the commit flag set. The frame checksum is
      # correct, but the contents of the database page are corrupt.
      #
      # The page-size in the log file header is set to $pgsz. If the
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      set fd [open test.db-wal w]
      fconfigure $fd -encoding binary -translation binary
      puts -nonewline $fd $walhdr
      puts -nonewline $fd $framehdr
      puts -nonewline $fd $framebody
      close $fd
  
      file size test.db-wal
    } [wal_file_size 1 $pgsz]
  
    do_test wal-18.2.$tn.$pg.5 {
      sqlite3 db test.db
      set rc [catch { db one {PRAGMA integrity_check} } msg]
      expr { $rc!=0 || $msg!="ok" }
    } $works
  
    db close
  }
}

#-------------------------------------------------------------------------
# The following test - wal-19.* - fixes a bug that was present during
# development.







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      set fd [open test.db-wal w]
      fconfigure $fd -encoding binary -translation binary
      puts -nonewline $fd $walhdr
      puts -nonewline $fd $framehdr
      puts -nonewline $fd $framebody
      close $fd

      file size test.db-wal
    } [wal_file_size 1 $pgsz]

    do_test wal-18.2.$tn.$pg.5 {
      sqlite3 db test.db
      set rc [catch { db one {PRAGMA integrity_check} } msg]
      expr { $rc!=0 || $msg!="ok" }
    } $works
 
    db close
  }
}

#-------------------------------------------------------------------------
# The following test - wal-19.* - fixes a bug that was present during
# development.

Added test/wal2big.test.



















































































































































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# 2017 September 19
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# TESTRUNNER: slow
#
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2big
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  CREATE INDEX t1a ON t1(a);
  CREATE INDEX t1b ON t1(b);
  CREATE INDEX t1c ON t1(c);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 10000000;

  WITH s(i) AS (
    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<200000
  )
  INSERT INTO t1 SELECT random(), random(), random() FROM s;
} {wal2 10000000}

do_execsql_test 1.1 {
  WITH s(i) AS (
    SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<200000
  )
  INSERT INTO t1 SELECT random(), random(), random() FROM s;
}

do_test 1.2 {
  list [expr [file size test.db-wal]>10000000] \
       [expr [file size test.db-wal2]>10000000]
} {1 1}

do_test 1.3 {
  sqlite3 db2 test.db
  execsql {
    SELECT count(*) FROM t1;
    PRAGMA integrity_check;
  } db2
} {400000 ok}

do_test 1.4 {
  db2 close
  forcecopy test.db test.db2
  forcecopy test.db-wal test.db2-wal
  forcecopy test.db-wal2 test.db2-wal2
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    PRAGMA integrity_check;
  }
} {400000 ok}

finish_test

Added test/wal2fault.test.









































































































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# 2010 May 03
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/malloc_common.tcl
source $testdir/lock_common.tcl

ifcapable !wal {finish_test ; return }
set testprefix wal2fault

do_execsql_test 1.0 {
  CREATE TABLE t1(x,y);
  PRAGMA journal_mode = wal2;
  WITH s(i) AS ( SELECT 100 UNION ALL SELECT i-1 FROM s WHERE (i-1)>0 )
  INSERT INTO t1 SELECT i, randomblob(i) FROM s;
  WITH s(i) AS ( SELECT 100 UNION ALL SELECT i-1 FROM s WHERE (i-1)>0 )
  INSERT INTO t1 SELECT i, randomblob(i) FROM s;
} {wal2}

do_test 1.1 {
  expr [file size test.db-wal]>10000
} {1}
faultsim_save_and_close

do_faultsim_test 1 -prep {
  faultsim_restore_and_reopen
  execsql {
    PRAGMA journal_size_limit = 10000;
    SELECT count(*) FROM sqlite_master;
  }
} -body {
  execsql {
    INSERT INTO t1 VALUES(1, 2);
  }
} -test {
  faultsim_test_result {0 {}}
}

finish_test

Added test/wal2lock.test.





















































































































































































































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# 2018 December 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2lock
ifcapable !wal {finish_test ; return }

db close
testvfs tvfs 
sqlite3 db test.db -vfs tvfs

do_execsql_test 1.0 {
  PRAGMA journal_mode = wal2;
  CREATE TABLE y1(y, yy);
  CREATE INDEX y1y ON y1(y);
  CREATE INDEX y1yy ON y1(yy);
  INSERT INTO y1 VALUES(1, 2), (3, 4), (5, 6);
} {wal2}

tvfs script vfs_callback
tvfs filter xShmLock

set ::lock [list]
proc vfs_callback {func file name lock} {
  lappend ::lock $lock
  return SQLITE_OK
}

do_execsql_test 1.1.1 {
  SELECT * FROM y1
} {1 2 3 4 5 6}
do_test 1.1.2 {
  set ::lock
} {{4 1 lock shared} {4 1 unlock shared}}

set ::bFirst 1
proc vfs_callback {func file name lock} {
  if {$::bFirst} {
    set ::bFirst 0
    return SQLITE_BUSY
  }
  return SQLITE_OK
}
do_execsql_test 1.2 {
  SELECT * FROM y1
} {1 2 3 4 5 6}

set ::bFirst 1
proc vfs_callback {func file name lock} {
  if {$::bFirst} {
    set ::bFirst 0
    return SQLITE_IOERR
  }
  return SQLITE_OK
}
do_catchsql_test 1.3 {
  SELECT * FROM y1
} {1 {disk I/O error}}

puts "# Warning: This next test case causes SQLite to call xSleep(1) 100 times."
puts "# Normally this equates to a delay of roughly 10 seconds, but if SQLite"
puts "# is built on unix without HAVE_USLEEP defined, it may be much longer."
proc vfs_callback {func file name lock} { return SQLITE_BUSY }
do_catchsql_test 1.4 {
  SELECT * FROM y1
} {1 {locking protocol}}
proc vfs_callback {func file name lock} { return SQLITE_OK }

sqlite3 db2 test.db -vfs tvfs
set ::bFirst 1

proc vfs_callback {func file name lock} {
  if {$::bFirst} {
    set ::bFirst 0
    db2 eval { INSERT INTO y1 VALUES(7, 8) }
  }
}

do_execsql_test 1.5.1 {
  SELECT * FROM y1
} {1 2 3 4 5 6 7 8}
do_execsql_test 1.5.2 {
  SELECT * FROM y1
} {1 2 3 4 5 6 7 8}

db close
db2 close
tvfs delete
finish_test

Added test/wal2openclose.test.



































































































































































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# 2017 September 19
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2openclose
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  PRAGMA journal_mode = wal2;
  PRAGMA wal_autocheckpoint = 0;
  PRAGMA journal_size_limit = 75000;
} {wal2 0 75000}

do_test 1.1 {
  for {set ii 1} {$ii <= 200} {incr ii} {
    execsql {
      INSERT INTO t1 VALUES($ii, $ii, $ii);
    }
  }
  expr ([file size test.db-wal2] - 75000) > 30000
} {1}

do_test 1.2 {
  db close
  list [file exists test.db-wal] [file exists test.db-wal2]
} {0 0}

sqlite3 db test.db
do_execsql_test 1.3 {
  SELECT sum(c) FROM t1
} {20100}
db close

#-------------------------------------------------------------------------
reset_db
do_execsql_test 2.0 {
  CREATE TABLE t1(a, b, c);
  PRAGMA journal_mode = wal2;
  INSERT INTO t1 VALUES(1, 2, 3);
} {wal2}
db_save_and_close

db_restore_and_reopen
do_execsql_test 2.1 {
  SELECT * FROM t1;
} {1 2 3}

do_test 2.2 {
  sqlite3 db2 test.db
  db2 eval {INSERT INTO t1 VALUES(4, 5, 6)}
  db2 close
} {}

breakpoint
db close
sqlite3 db test.db
do_execsql_test 2.2 {
  SELECT * FROM t1;
} {1 2 3 4 5 6}



finish_test

Added test/wal2recover.test.

































































































































































































































































































































































































































































































































































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# 2018 December 13
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2recover
ifcapable !wal {finish_test ; return }

proc db_copy {from to} {
  forcecopy $from $to
  forcecopy ${from}-wal ${to}-wal
  forcecopy ${from}-wal2 ${to}-wal2
}

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  CREATE INDEX t1a ON t1(a);
  CREATE INDEX t1b ON t1(b);
  CREATE INDEX t1c ON t1(c);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 15000;
  PRAGMA wal_autocheckpoint = 0;
} {wal2 15000 0}

do_test 1.1 {
  for {set i 1} {$i <= 1000} {incr i} {
    execsql { INSERT INTO t1 VALUES(random(), random(), random()) }
    db_copy test.db test.db2
    sqlite3 db2 test.db
    set res [execsql {
      SELECT count(*) FROM t1;
      PRAGMA integrity_check;
    } db2]
    db2 close
    if {$res != [list $i ok]} {
      error "failure on iteration $i"
    }
  }
  set {} {}
} {}

#--------------------------------------------------------------------------
reset_db
do_execsql_test 2.0 {
  CREATE TABLE t1(x UNIQUE);
  CREATE TABLE t2(x UNIQUE);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 10000;
  PRAGMA wal_autocheckpoint = 0;
  BEGIN;
    INSERT INTO t1 VALUES(randomblob(4000));
    INSERT INTO t1 VALUES(randomblob(4000));
    INSERT INTO t1 VALUES(randomblob(4000));
  COMMIT;
  BEGIN;
    INSERT INTO t2 VALUES(randomblob(4000));
    INSERT INTO t2 VALUES(randomblob(4000));
    INSERT INTO t2 VALUES(randomblob(4000));
  COMMIT;
} {wal2 10000 0}
do_test 2.0.1 {
  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
} {5120 28328 28328}

# Test recovery with both wal files intact.
#
do_test 2.1 {
  db_copy test.db test.db2
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  } db2
} {3 3 ok}

do_test 2.2 {
  db2 close
  db_copy test.db test.db2
  hexio_write test.db2-wal 16 12345678
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
  } db2
} {0 3}

do_test 2.3 {
  db2 close
  db_copy test.db test.db2
  hexio_write test.db2-wal2 16 12345678
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  } db2
} {3 0 ok}

do_test 2.4 {
  db2 close
  db_copy test.db test.db2
  forcecopy test.db-wal test.db2-wal2
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  } db2
} {3 0 ok}

do_test 2.5 {
  db2 close
  db_copy test.db test.db2
  forcecopy test.db-wal  test.db2-wal2
  forcecopy test.db-wal2  test.db2-wal
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  } db2
} {3 3 ok}

do_test 2.6 {
  db2 close
  db_copy test.db test.db2
  forcecopy test.db-wal test.db2-wal2
  close [open test.db-wal w]
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  } db2
} {3 0 ok}

do_test 2.7 {
  db2 close
  db_copy test.db test.db2
  forcedelete test.db2-wal
  sqlite3 db2 test.db2
  execsql {
    SELECT count(*) FROM t1;
    SELECT count(*) FROM t2;
    PRAGMA integrity_check;
  } db2
} {0 0 ok}
db2 close

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 3.0 {
  CREATE TABLE t1(a TEXT, b TEXT, c TEXT);
  CREATE INDEX t1a ON t1(a);
  CREATE INDEX t1b ON t1(b);
  CREATE INDEX t1c ON t1(c);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 10000;
  PRAGMA wal_autocheckpoint = 0;
  PRAGMA cache_size = 5;
} {wal2 10000 0}

do_execsql_test 3.1 {
  WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 200)
  INSERT INTO t1 SELECT i, i, i FROM s;

  INSERT INTO t1 VALUES(201, 201, 201);
} {}

do_test 3.2 {
  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
} {5120 15752 4224}

do_test 3.3 {
  forcecopy test.db test.db2
  forcecopy test.db-wal test.db2-wal
  forcecopy test.db-wal2 test.db2-wal2
  sqlite3 db2 test.db2
  execsql {
    PRAGMA journal_size_limit = 10000;
    PRAGMA wal_autocheckpoint = 0;
    PRAGMA cache_size = 5;
    BEGIN;
      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 200)
      INSERT INTO t1 SELECT i, i, i FROM s;
  } db2
  list [file size test.db2] [file size test.db2-wal] [file size test.db2-wal2]
} {5120 15752 23088}


if {$tcl_platform(platform)!="windows"} {
  # These cannot be run under windows, as the *-shm file may not be read
  # while it is locked by the database connection. 
  do_test 3.4 {
    set fd [open test.db2-shm]
    fconfigure $fd -encoding binary -translation binary
    set data [read $fd]
    close $fd
  
    set fd [open test.db-shm w]
    fconfigure $fd -encoding binary -translation binary
    puts -nonewline $fd $data
    close $fd
  
    execsql {
      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 10)
        INSERT INTO t1 SELECT i, i, i FROM s;
      SELECT count(*) FROM t1;
      PRAGMA integrity_check;
    }
  } {211 ok}
  
  do_test 3.5 {
    list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
  } {5120 15752 18896}
}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 4.0 {
  PRAGMA journal_mode = wal2;
  CREATE TABLE xyz(x, y, z);
  INSERT INTO xyz VALUES('x', 'y', 'z');
} {wal2}
db close
do_test 4.1 {
  close [open test.db-wal w]
  file mkdir test.db-wal2
  sqlite3 db test.db
  catchsql { SELECT * FROM xyz }
} {1 {unable to open database file}}
db close
file delete test.db-wal2
db2 close

do_test 4.2 {
  sqlite3 db test.db
  execsql { 
    INSERT INTO xyz VALUES('a', 'b', 'c');
  }
  forcecopy test.db test.db2
  forcecopy test.db-wal test.db2-wal
  forcedelete test.db2-wal2
  file mkdir test.db2-wal2
  sqlite3 db2 test.db2
  catchsql { SELECT * FROM xyz } db2
} {1 {unable to open database file}}
db2 close
file delete test.db2-wal2


finish_test

Added test/wal2recover2.test.



































































































































































































































































































































































































































































































































































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# 2018 December 13
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2recover2
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(x);
  CREATE TABLE t2(x);
  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t1 SELECT i FROM s;
  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t2 SELECT i FROM s;

  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 10000;
} {wal2 10000}

set ::L 1125750
set ::M 1126500
set ::H 1127250

do_execsql_test 1.1 {
  UPDATE t1 SET x=x+1;
  UPDATE t2 SET x=x+1 WHERE rowid<=750;

  SELECT sum(x) FROM t1;
  SELECT sum(x) FROM t2;
} [list $H $M]

do_test 1.2 {
  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
} {31744 14704 7368}

proc cksum {zIn data} {
  if {[string length $zIn]==0} {
    set s0 0
    set s1 0
  } else {
    set s0 [hexio_get_int [string range $zIn 0 7]]
    set s1 [hexio_get_int [string range $zIn 8 15]]
  }
  set n [expr [string length $data] / 8]

  for {set i 0} {$i < $n} {incr i 2} {
    set x0 [hexio_get_int -l [string range $data [expr $i*8]   [expr $i*8+7]]]
    set x1 [hexio_get_int -l [string range $data [expr $i*8+8] [expr $i*8+8+7]]]

    set s0 [expr ($s0 + $x0 + $s1) & 0xFFFFFFFF]
    set s1 [expr ($s1 + $x1 + $s0) & 0xFFFFFFFF]
  }

  return "[hexio_render_int32 $s0][hexio_render_int32 $s1]"
}

proc fix_wal_cksums {file} {
  # Fix the checksum on the wal header.
  set data [hexio_read $file 0 32]
  set cksum [cksum {} [string range $data 0 47]]
  set salt [hexio_read $file 16 8]
  hexio_write $file 24 $cksum

  # Fix the checksums for all pages in the wal file.
  set pgsz [hexio_get_int [hexio_read $file 8 4]]
  set sz [file size $file]
  for {set off 32} {$off < $sz} {incr off [expr $pgsz+24]} {
    set e [hexio_read $file $off 8]
    set cksum [cksum $cksum $e]

    set p [hexio_read $file [expr $off+24] $pgsz]
    set cksum [cksum $cksum $p]

    hexio_write $file [expr $off+8] $salt
    hexio_write $file [expr $off+16] $cksum
  }
}

proc wal_incr_hdrfield {file field} {
  switch -- $field {
    nCkpt { set offset 12 }
    salt0 { set offset 16 }
    salt1 { set offset 20 }
    default {
      error "unknown field $field - should be \"nCkpt\", \"salt0\" or \"salt1\""
    }
  }

  # Increment the value in the wal header.
  set v [hexio_get_int [hexio_read $file $offset 4]]
  incr v
  hexio_write $file $offset [hexio_render_int32 $v]
  
  # Fix various checksums
  fix_wal_cksums $file
}

proc wal_set_nckpt {file val} {
  # Increment the value in the wal header.
  hexio_write $file 12 [hexio_render_int32 $val]
  
  # Fix various checksums
  fix_wal_cksums $file
}

proc wal_set_follow {file prevfile} {
  set pgsz [hexio_get_int [hexio_read $prevfile 8 4]]
  set sz [file size $prevfile]
  set cksum [hexio_read $prevfile [expr $sz-$pgsz-8] 8]

  hexio_write $file 16 $cksum
  fix_wal_cksums $file
}

foreach {tn file field} {
  1 test.db2-wal    salt0
  2 test.db2-wal    salt1
  3 test.db2-wal    nCkpt
  4 test.db2-wal2   salt0
  5 test.db2-wal2   salt1
  6 test.db2-wal2   nCkpt
} {
  do_test 1.3.$tn {
    forcecopy test.db test.db2
    forcecopy test.db-wal test.db2-wal
    forcecopy test.db-wal2 test.db2-wal2
    wal_incr_hdrfield $file $field
    sqlite3 db2 test.db2
    execsql {
      SELECT sum(x) FROM t1;
      SELECT sum(x) FROM t2;
    } db2
  } [list $H $L]
  db2 close
}

do_test 1.4 {
  forcecopy test.db test.db2
  forcecopy test.db-wal2 test.db2-wal
  forcedelete test.db2-wal2
  sqlite3 db2 test.db2
  execsql {
    SELECT sum(x) FROM t1;
    SELECT sum(x) FROM t2;
  } db2
} [list $L $M]

do_test 1.5 {
  db2 close
  forcecopy test.db test.db2
  forcecopy test.db-wal2 test.db2-wal
  forcecopy test.db-wal test.db2-wal2
  sqlite3 db2 test.db2
  execsql {
    SELECT sum(x) FROM t1;
    SELECT sum(x) FROM t2;
  } db2
} [list $H $M]

db2 close
foreach {tn file field} {
  1 test.db2-wal    salt0
  2 test.db2-wal    salt1
  3 test.db2-wal2   salt0
  4 test.db2-wal2   salt1
} {
  do_test 1.6.$tn {
    forcecopy test.db test.db2
    forcecopy test.db-wal2 test.db2-wal
    forcecopy test.db-wal test.db2-wal2
    wal_incr_hdrfield $file $field
    sqlite3 db2 test.db2
    execsql {
      SELECT sum(x) FROM t1;
      SELECT sum(x) FROM t2;
    } db2
  } [list $H $L]
  db2 close
}

foreach {tn nCkpt1 nCkpt2 res} [list \
  1   2 1   "$H $M"                  \
  2   2 2   "$L $M"                  \
  3   3 1   "$H $L"                  \
  4   15 14 "$H $M"                  \
  5   0 15  "$H $M"                  \
  6   1 15  "$L $M"                  \
] {
  do_test 1.7.$tn {
    forcecopy test.db test.db2
    forcecopy test.db-wal2 test.db2-wal
    forcecopy test.db-wal test.db2-wal2

    wal_set_nckpt test.db2-wal2 $nCkpt2
    wal_set_nckpt test.db2-wal  $nCkpt1
    wal_set_follow test.db2-wal test.db2-wal2


    sqlite3 db2 test.db2
    execsql {
      SELECT sum(x) FROM t1;
      SELECT sum(x) FROM t2;
    } db2
  } $res
  db2 close
}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 1.8.1 {
  PRAGMA autovacuum = 0;
  PRAGMA page_size = 4096;
  CREATE TABLE t1(x);
  CREATE TABLE t2(x);
  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t1 SELECT i FROM s;
  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t2 SELECT i FROM s;

  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 10000;

  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t2 SELECT i FROM s;
} {wal2 10000}

do_test 1.8.2 {
  list [file size test.db-wal] [file size test.db-wal2]
} {24752 0}

do_execsql_test 1.8.3 { PRAGMA user_version = 123 }
do_test 1.8.4 {
  list [file size test.db-wal] [file size test.db-wal2]
} {24752 4152}

do_test 1.8.5 {
  hexio_write test.db-wal2 [expr 56+16] 0400
  fix_wal_cksums test.db-wal2
} {}

ifcapable oversize_cell_check {
  set msg {database disk image is malformed}
} else {
  set msg {malformed database schema (?)}
}

do_test 1.8.6 {
  forcecopy test.db test.db2
  forcecopy test.db-wal test.db2-wal
  forcecopy test.db-wal2 test.db2-wal2
  sqlite3 db2 test.db2
  catchsql { SELECT * FROM sqlite_master } db2
} [list 1 $msg]
db2 close

finish_test

Added test/wal2recover3.test.









































































































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# 2022 June 28
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2recover3
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(x);
  CREATE TABLE t2(x);
  PRAGMA journal_mode = wal2;
  PRAGMA wal_autocheckpoint = 0;
  PRAGMA journal_size_limit = 10000;
} {wal2 0 10000}

do_execsql_test 1.1 {
  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t1 SELECT i FROM s;
  WITH s(i) AS ( VALUES(1) UNION ALL SELECT i+1 FROM s WHERE i<1500 )
    INSERT INTO t2 SELECT i FROM s;
}

db_save_and_close
set fd [open sv_test.db-wal2 r+]
seek $fd 4000
puts -nonewline $fd 0
close $fd

db_restore_and_reopen
do_execsql_test 1.2 {
  SELECT sql FROM sqlite_schema;
} {{CREATE TABLE t1(x)} {CREATE TABLE t2(x)}}

finish_test

Added test/wal2rewrite.test.

























































































































































































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# 2017 September 19
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2rewrite
ifcapable !wal {finish_test ; return }

proc filesize {filename} {
  if {[file exists $filename]} {
    return [file size $filename]
  }
  return 0
}

foreach {tn jrnlmode} {
  1 wal
  2 wal2
} {
  reset_db
  execsql "PRAGMA journal_mode = $jrnlmode"
  do_execsql_test $tn.1 {
    PRAGMA journal_size_limit = 10000;
    PRAGMA cache_size = 5;
    PRAGMA wal_autocheckpoint = 10;
  
    CREATE TABLE t1(a INTEGER PRIMARY KEY, b INTEGER, c BLOB);
    CREATE INDEX t1b ON t1(b);
    CREATE INDEX t1c ON t1(c);
  
    WITH s(i) AS (
      SELECT 1 UNION SELECT i+1 FROM s WHERE i<10
    )
    INSERT INTO t1 SELECT i, i, randomblob(800) FROM s;
  } {10000 10}
  
  for {set i 0} {$i < 4} {incr i} {
    do_execsql_test $tn.$i.1 {
      UPDATE t1 SET c=randomblob(800) WHERE (b%10)==5 AND ($i%2)
    }
    do_execsql_test $tn.$i.2 {
      BEGIN;
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
      UPDATE t1 SET b=b+10, c=randomblob(800);
    }
    execsql COMMIT

    do_test $tn.$i.3 { expr [filesize test.db-wal]  < 100000 } 1
    do_test $tn.$i.4 { expr [filesize test.db-wal2] < 100000 } 1

    set sum [db eval {SELECT sum(b), md5sum(c) FROM t1}]

    do_test $tn.$i.5 {
      foreach f [glob -nocomplain test.db2*] {forcedelete $f}
      foreach f [glob -nocomplain test.db*] {
        forcecopy $f [string map {test.db test.db2} $f]
      }

      sqlite3 db2 test.db2
      db2 eval {SELECT sum(b), md5sum(c) FROM t1}
    } $sum
    db2 close
  }
}
    


finish_test

Added test/wal2rollback.test.





























































































































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# 2017 September 19
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2rollback
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  CREATE TABLE t2(a, b, c);
  CREATE INDEX i1 ON t1(a);
  CREATE INDEX i2 ON t1(b);
  PRAGMA journal_mode = wal2;
  PRAGMA cache_size = 5;
  PRAGMA journal_size_limit = 10000;
  WITH s(i) AS (
    SELECT 1 UNION ALL SELECT i+1 FROM s LIMIT 1000
  )
  INSERT INTO t1 SELECT i, i, randomblob(200) FROM s;
} {wal2 10000}

do_test 1.1 {
  expr [file size test.db-wal] > 10000
} 1

do_test 1.2 {
  execsql {
    BEGIN;
      UPDATE t1 SET b=b+1;
      INSERT INTO t2 VALUES(1,2,3);
  }
  expr [file size test.db-wal2] > 10000
} {1}

breakpoint
do_execsql_test 1.3 {
  ROLLBACK;
  SELECT * FROM t2;
  SELECT count(*) FROM t1 WHERE a=b;
  PRAGMA integrity_check;
} {1000 ok}



finish_test

Added test/wal2savepoint.test.



















































































































































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# 2018 December 13
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2savepoint
ifcapable !wal {finish_test ; return }

do_execsql_test 1.0 {
  CREATE TABLE t1(a, b, c);
  CREATE INDEX t1a ON t1(a);
  CREATE INDEX t1b ON t1(b);
  CREATE INDEX t1c ON t1(c);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 15000;
  PRAGMA wal_autocheckpoint = 0;
  PRAGMA cache_size = 5;
} {wal2 15000 0}

do_execsql_test 1.1 {
  WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 200)
  INSERT INTO t1 SELECT random(), random(), random() FROM s;
} {}

do_test 1.2 {
  list [file size test.db] [file size test.db-wal] [file size test.db-wal2]
} {5120 23088 0}

do_execsql_test 1.3 {
  BEGIN;
    SAVEPOINT abc;
      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 100)
      INSERT INTO t1 SELECT random(), random(), random() FROM s;
    ROLLBACK TO abc;
    WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 10)
    INSERT INTO t1 SELECT random(), random(), random() FROM s;
  COMMIT;
  SELECT count(*) FROM t1;
  PRAGMA integrity_check;
} {210 ok}

do_execsql_test 1.4 {
  BEGIN;
    SAVEPOINT abc;
      WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 100)
      INSERT INTO t1 SELECT random(), random(), random() FROM s;
    ROLLBACK TO abc;
    WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s where i < 10)
    INSERT INTO t1 SELECT random(), random(), random() FROM s;
  COMMIT;
  SELECT count(*) FROM t1;
  PRAGMA integrity_check;
} {220 ok}


finish_test

Added test/wal2simple.test.























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































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# 2017 September 19
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl
source $testdir/wal_common.tcl

set testprefix wal2simple
ifcapable !wal {finish_test ; return }

#-------------------------------------------------------------------------
# The following tests verify that a client can switch in and out of wal
# and wal2 mode. But that it is not possible to change directly from wal
# to wal2, or from wal2 to wal mode.
#
do_execsql_test 1.1.0 {
  PRAGMA journal_mode = wal2
} {wal2}
execsql { SELECT * FROM sqlite_master} 
do_execsql_test 1.x {
  PRAGMA journal_mode;
  PRAGMA main.journal_mode;
} {wal2 wal2}
db close
do_test 1.1.1 { file size test.db } {1024}
do_test 1.1.2 { hexio_read test.db 18 2 } 0303

sqlite3 db test.db
do_execsql_test 1.2.0 {
  SELECT * FROM sqlite_master;
  PRAGMA journal_mode = delete;
} {delete}
db close
do_test 1.2.1 { file size test.db } {1024}
do_test 1.2.2 { hexio_read test.db 18 2 } 0101

sqlite3 db test.db
do_execsql_test 1.3.0 {
  SELECT * FROM sqlite_master;
  PRAGMA journal_mode = wal;
} {wal}
db close
do_test 1.3.1 { file size test.db } {1024}
do_test 1.3.2 { hexio_read test.db 18 2 } 0202

sqlite3 db test.db
do_catchsql_test 1.4.0 {
  PRAGMA journal_mode = wal2;
} {1 {cannot change from wal to wal2 mode}}
do_execsql_test 1.4.1 {
  PRAGMA journal_mode = wal;
  PRAGMA journal_mode = delete;
  PRAGMA journal_mode = wal2;
  PRAGMA journal_mode = wal2;
} {wal delete wal2 wal2}
do_catchsql_test 1.4.2 {
  PRAGMA journal_mode = wal;
} {1 {cannot change from wal2 to wal mode}}
db close
do_test 1.4.3 { hexio_read test.db 18 2 } 0303

#-------------------------------------------------------------------------
# Test that recovery in wal2 mode works.
#
forcedelete test.db test.db-wal test.db-wal2
reset_db
do_execsql_test 2.0 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 5000;
} {wal2 5000}

proc wal_hook {DB nm nFrame} { $DB eval { PRAGMA wal_checkpoint } }
db wal_hook {wal_hook db}

for {set i 1} {$i <= 200} {incr i} {
  execsql { INSERT INTO t1 VALUES(NULL, randomblob(100)) }
  set res [db eval { SELECT sum(a), md5sum(b) FROM t1 }]

  do_test 2.1.$i {
    foreach f [glob -nocomplain test.db2*] { forcedelete $f }
    forcecopy test.db      test.db2
    forcecopy test.db-wal  test.db2-wal
    forcecopy test.db-wal2 test.db2-wal2

    sqlite3 db2 test.db2
    db2 eval { SELECT sum(a), md5sum(b) FROM t1 }
  } $res

  db2 close
}

#-------------------------------------------------------------------------

reset_db
do_execsql_test 3.0 {
  CREATE TABLE t1(x BLOB, y INTEGER PRIMARY KEY);
  CREATE INDEX i1 ON t1(x);
  PRAGMA cache_size = 5;
  PRAGMA journal_mode = wal2;
} {wal2}

do_test 3.1 {
  execsql BEGIN
  for {set i 1} {$i < 1000} {incr i} {
    execsql { INSERT INTO t1 VALUES(randomblob(800), $i) }
  }
  execsql COMMIT
} {}

do_execsql_test 3.2 {
  PRAGMA integrity_check;
} {ok}

#-------------------------------------------------------------------------
catch { db close }
foreach f [glob -nocomplain test.db*] { forcedelete $f }
reset_db
do_execsql_test 4.0 {
  CREATE TABLE t1(x, y);
  PRAGMA journal_mode = wal2;
} {wal2}

do_execsql_test 4.1 {
  SELECT * FROM t1;
} {}

do_execsql_test 4.2 {
  INSERT INTO t1 VALUES(1, 2);
} {}

do_execsql_test 4.3 {
  SELECT * FROM t1;
} {1 2}

do_test 4.4 {
  sqlite3 db2 test.db
  execsql { SELECT * FROM t1 } db2
} {1 2}

do_test 4.5 {
  lsort [glob test.db*]
} {test.db test.db-shm test.db-wal test.db-wal2}

do_test 4.6 {
  db close
  db2 close
  sqlite3 db test.db
  execsql { SELECT * FROM t1 }
} {1 2}

do_execsql_test 4.7 {
  PRAGMA journal_size_limit = 4000;
  INSERT INTO t1 VALUES(3, 4);
  INSERT INTO t1 VALUES(5, 6);
  INSERT INTO t1 VALUES(7, 8);
  INSERT INTO t1 VALUES(9, 10);
  INSERT INTO t1 VALUES(11, 12);
  INSERT INTO t1 VALUES(13, 14);
  INSERT INTO t1 VALUES(15, 16);
  INSERT INTO t1 VALUES(17, 18);
  SELECT * FROM t1;
} {4000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18}

do_test 4.8 {
  sqlite3 db2 test.db
  execsql { SELECT * FROM t1 } db2
} {1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18}

do_test 4.9 {
  db close
  db2 close
  lsort [glob test.db*]
} {test.db}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 5.0 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
  CREATE INDEX i1 ON t1(b, c);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 4000;
} {wal2 4000}

proc wal_hook {DB nm nFrame} {
  $DB eval { PRAGMA wal_checkpoint }
}
db wal_hook [list wal_hook db]


foreach js {4000 8000 12000} {
  foreach NROW [list 100 200 300 400 500 600 1000] {
    do_test 5.$js.$NROW.1 {
      db eval "DELETE FROM t1"
      db eval "PRAGMA journal_size_limit = $js"
      set nTotal 0
      for {set i 0} {$i < $NROW} {incr i} {
        db eval { INSERT INTO t1 VALUES($i, $i, randomblob(abs(random()%50))) }
        incr nTotal $i
      }
      set {} {}
    } {}

    do_test 5.$js.$NROW.2 {
      sqlite3 db2 test.db
      db2 eval { 
        PRAGMA integrity_check;
        SELECT count(*), sum(b) FROM t1;
      }
    } [list ok $NROW $nTotal]

    db2 close
  }
}


#-------------------------------------------------------------------------
reset_db
do_execsql_test 6.0 {
  CREATE TABLE tx(x);
  PRAGMA journal_mode = wal2;
  PRAGMA journal_size_limit = 3500;
} {wal2 3500}

do_test 6.1 {
  for {set i 0} {$i < 10} {incr i} {
    execsql "CREATE TABLE t$i (x);"
  }
} {}

do_test 6.2.1 {
  foreach f [glob -nocomplain test.db2*] { forcedelete $f }
  forcecopy test.db-wal2 test.db2-wal2
  sqlite3 db2 test.db2
  db2 eval { SELECT * FROM sqlite_master }
} {}
do_test 6.2.2 {
  db2 eval {
    PRAGMA journal_mode = wal2;
    SELECT * FROM sqlite_master;
  }
} {wal2}

do_test 6.3.1 {
  db2 close
  foreach f [glob -nocomplain test.db2*] { forcedelete $f }
  forcecopy test.db-wal2 test.db2-wal2
  forcecopy test.db test.db2
  sqlite3 db2 test.db2
  db2 eval { SELECT * FROM sqlite_master }
} {table tx tx 2 {CREATE TABLE tx(x)}}
do_test 6.3.2 {
  db2 eval {
    PRAGMA journal_mode = wal2;
    SELECT * FROM sqlite_master;
  }
} {wal2 table tx tx 2 {CREATE TABLE tx(x)}}

do_test 6.4.1 {
  db2 close
  foreach f [glob -nocomplain test.db2*] { forcedelete $f }
  forcecopy test.db-wal2 test.db2-wal2
  forcecopy test.db-wal test.db2-wal
  sqlite3 db2 test.db2
  db2 eval { SELECT * FROM sqlite_master }
} {}
do_test 6.4.2 {
  db2 eval {
    PRAGMA journal_mode = wal2;
    SELECT * FROM sqlite_master;
  }
} {wal2}
db2 close

#-------------------------------------------------------------------------
reset_db
sqlite3 db2 test.db
do_execsql_test 7.0 {
  PRAGMA journal_size_limit = 10000;
  PRAGMA journal_mode = wal2;
  PRAGMA wal_autocheckpoint = 0;
  BEGIN;
    CREATE TABLE t1(a);
    INSERT INTO t1 VALUES( randomblob(8000) );
  COMMIT;
} {10000 wal2 0}

do_test 7.1 {
  list [file size test.db-wal] [file size test.db-wal2]
} {9464 0}

# Connection db2 is holding a PART1 lock. 
#
#   7.2.2: Test that the PART1 does not prevent db from switching to the
#          other wal file.
#
#   7.2.3: Test that the PART1 does prevent a checkpoint of test.db-wal.
#
#   7.2.4: Test that after the PART1 is released the checkpoint is possible.
#
do_test 7.2.1 {
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
} {1}
do_test 7.2.2 {
  execsql {
    INSERT INTO t1 VALUES( randomblob(800) );
    INSERT INTO t1 VALUES( randomblob(800) );
  }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {13656 3176 1024}
do_test 7.2.3 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {13656 3176 1024}
do_test 7.2.4 {
  execsql { END } db2
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {13656 3176 11264}

# Connection db2 is holding a PART2_FULL1 lock. 
#
#   7.3.2: Test that the lock does not prevent checkpointing.
#
#   7.3.3: Test that the lock does prevent the writer from overwriting 
#          test.db-wal.
#
#   7.3.4: Test that after the PART2_FULL1 is released the writer can
#          switch wal files and overwrite test.db-wal
#
db close
db2 close
sqlite3 db test.db
sqlite3 db2 test.db
do_test 7.3.1 {
  execsql {
    PRAGMA wal_autocheckpoint = 0;
    PRAGMA journal_size_limit = 10000;
    INSERT INTO t1 VALUES(randomblob(10000));
    INSERT INTO t1 VALUES(randomblob(500));
  }
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 3176 12288}
do_test 7.3.2 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 3176 22528}
do_test 7.3.3 {
  execsql { 
    INSERT INTO t1 VALUES(randomblob(10000));
    INSERT INTO t1 VALUES(randomblob(500));
  }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 18896 22528}
do_test 7.3.4 {
  execsql END db2
  execsql { INSERT INTO t1 VALUES(randomblob(5000)); }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 18896 22528}

# Connection db2 is holding a PART2 lock. 
#
#   7.4.2: Test that the lock does not prevent writer switching to test.db-wal.
#
#   7.3.3: Test that the lock does prevent checkpointing of test.db-wal2.
#
#   7.3.4: Test that after the PART2 is released test.db-wal2 can be
#          checkpointed.
#
db close
db2 close
breakpoint
sqlite3 db test.db
sqlite3 db2 test.db
do_test 7.4.1 {
  execsql {
    PRAGMA wal_autocheckpoint = 0;
    PRAGMA journal_size_limit = 10000;
    INSERT INTO t1 VALUES(randomblob(10000));
    INSERT INTO t1 VALUES(randomblob(10000));
    PRAGMA wal_checkpoint;
  }
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 50176}
do_test 7.4.2 {
  execsql { 
    INSERT INTO t1 VALUES(randomblob(5000));
  }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 50176}
do_test 7.4.3 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 50176}
do_test 7.4.4 {
  execsql END db2
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 60416}

# Connection db2 is holding a PART1_FULL2 lock. 
#
#   7.5.2: Test that the lock does not prevent a checkpoint of test.db-wal2.
#
#   7.5.3: Test that the lock does prevent the writer from overwriting
#          test.db-wal2.
#
#   7.5.4: Test that after the PART1_FULL2 lock is released, the writer
#          can switch to test.db-wal2.
#
db close
db2 close
sqlite3 db test.db
sqlite3 db2 test.db
do_test 7.5.1 {
  execsql {
    PRAGMA wal_autocheckpoint = 0;
    PRAGMA journal_size_limit = 10000;
    INSERT INTO t1 VALUES(randomblob(10000));
    INSERT INTO t1 VALUES(randomblob(10000));
    PRAGMA wal_checkpoint;
    INSERT INTO t1 VALUES(randomblob(5000));
  }
  execsql {
    BEGIN;
      SELECT count(*) FROM t1;
  } db2
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 76800}
do_test 7.5.2 {
  execsql { PRAGMA wal_checkpoint }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {12608 12608 87040}
do_test 7.5.3.1 {
  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {14704 12608 87040}
do_test 7.5.3.2 {
  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {22040 12608 87040}
do_test 7.5.4 {
  execsql END db2
  execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
  list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
} {22040 12608 87040}


finish_test

Added test/wal2snapshot.test.



























































































































































































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# 2018 December 5
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the operation of the library in
# "PRAGMA journal_mode=WAL2" mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

set testprefix wal2snapshot
ifcapable !wal {finish_test ; return }
ifcapable !snapshot {finish_test; return}

foreach {tn mode} {1 wal 2 wal2} {
  reset_db
  do_execsql_test $tn.1 "PRAGMA journal_mode = $mode" $mode

  do_execsql_test $tn.2 {
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
    INSERT INTO t1 VALUES(3, 4);
    BEGIN;
  }

  # Check that sqlite3_snapshot_get() is an error for a wal2 db.
  #
  if {$tn==1} {
    do_test 1.3 {
      set S [sqlite3_snapshot_get db main]
      sqlite3_snapshot_free $S
    } {}
  } else {
    do_test 2.3 {
      list [catch { sqlite3_snapshot_get db main } msg] $msg
    } {1 SQLITE_ERROR}
  }
  
  # Check that sqlite3_snapshot_recover() is an error for a wal2 db.
  #
  do_execsql_test $tn.4 COMMIT
  if {$tn==1} {
    do_test 1.5 {
      sqlite3_snapshot_recover db main
    } {}
  } else {
    do_test 2.5 {
      list [catch { sqlite3_snapshot_recover db main } msg] $msg
    } {1 SQLITE_ERROR}
  }
 
  # Check that sqlite3_snapshot_open() is an error for a wal2 db.
  #
  if {$tn==1} {
    do_test 1.6 {
      execsql BEGIN
      set SNAPSHOT [sqlite3_snapshot_get_blob db main]
      sqlite3_snapshot_open_blob db main $SNAPSHOT
      execsql COMMIT
    } {}
  } else {
    do_test 2.6.1 {
      execsql BEGIN
      set res [
        list [catch { sqlite3_snapshot_open_blob db main $SNAPSHOT } msg] $msg
      ]
      execsql COMMIT
      set res
    } {1 SQLITE_ERROR}
    do_test 2.6.2 {
      execsql BEGIN
      execsql {SELECT * FROM sqlite_master}
      set res [
        list [catch { sqlite3_snapshot_open_blob db main $SNAPSHOT } msg] $msg
      ]
      execsql COMMIT
      set res
    } {1 SQLITE_ERROR}
  }
}


finish_test


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#
proc lock_callback {method filename handle lock} {
  if {$lock=="0 1 lock exclusive"} {
    proc lock_callback {method filename handle lock} {}
    db2 eval { INSERT INTO x VALUES('x') }
  }
}
db timeout 10
do_catchsql_test 2.4 {
  BEGIN EXCLUSIVE;
} {0 {}}
do_execsql_test 2.5 {
  SELECT * FROM x;
  COMMIT;
} {z y x}







|







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#
proc lock_callback {method filename handle lock} {
  if {$lock=="0 1 lock exclusive"} {
    proc lock_callback {method filename handle lock} {}
    db2 eval { INSERT INTO x VALUES('x') }
  }
}
db timeout 1100
do_catchsql_test 2.4 {
  BEGIN EXCLUSIVE;
} {0 {}}
do_execsql_test 2.5 {
  SELECT * FROM x;
  COMMIT;
} {z y x}

Changes to tool/mkctimec.tcl.

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  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
#elif defined(THREADSAFE)
  "THREADSAFE=" CTIMEOPT_VAL(THREADSAFE),
#else
  "THREADSAFE=1",
#endif
}



proc trim_name {in} {
  set ret $in
  if {[string range $in 0 6]=="SQLITE_"} {
    set ret [string range $in 7 end]
  }
  return $ret







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  "THREADSAFE=" CTIMEOPT_VAL(SQLITE_THREADSAFE),
#elif defined(THREADSAFE)
  "THREADSAFE=" CTIMEOPT_VAL(THREADSAFE),
#else
  "THREADSAFE=1",
#endif
}

set options(WAL2) { "WAL2", }

proc trim_name {in} {
  set ret $in
  if {[string range $in 0 6]=="SQLITE_"} {
    set ret [string range $in 7 end]
  }
  return $ret