SQLite

/*
** 2007 August 22
**
** 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.
**
*************************************************************************
**
** @(#) $Id: journal.c,v 1.2 2007/08/23 08:06:45 danielk1977 Exp $
*/

#ifdef SQLITE_ENABLE_ATOMIC_WRITE

/*
** This file implements a special kind of sqlite3_file object used
** by SQLite to create journal files if the atomic-write optimization

/*
** If it does not already exists, create and populate the on-disk file 
** for JournalFile p.
*/
static int createFile(JournalFile *p){
  int rc = SQLITE_OK;
  if( !p->pReal ){
    sqlite3_file *pReal = (sqlite3_file *)&p[1];
    rc = sqlite3OsOpen(p->pVfs, p->zJournal, pReal, p->flags, 0);
    if( rc==SQLITE_OK ){
      p->pReal = pReal;
      if( p->iSize>0 ){
        assert(p->iSize<=p->nBuf);
        rc = sqlite3OsWrite(p->pReal, p->zBuf, p->iSize, 0);
      }
    }
  }
  return rc;
}

/*
** Close the file.

}
int sqlite3OsBreakLock(sqlite3_file *id){
  return id->pMethods->xBreakLock(id);
}
int sqlite3OsCheckReservedLock(sqlite3_file *id){
  return id->pMethods->xCheckReservedLock(id);
}

#ifdef SQLITE_TEST
  /* The following two variables are used to override the values returned
  ** by the xSectorSize() and xDeviceCharacteristics() vfs methods for
  ** testing purposes. They are usually set by a test command implemented
  ** in test6.c.
  */
  int sqlite3_test_sector_size = 0;
  int sqlite3_test_device_characteristics = 0;
  int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
    int dc = id->pMethods->xDeviceCharacteristics(id);
    return dc | sqlite3_test_device_characteristics;
  }
  int sqlite3OsSectorSize(sqlite3_file *id){
    if( sqlite3_test_sector_size==0 ){
      int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
      return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
    }
    return sqlite3_test_sector_size;
  }
#else
  int sqlite3OsSectorSize(sqlite3_file *id){
    int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
    return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
  }
  int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
    return id->pMethods->xDeviceCharacteristics(id);
  }
#endif

#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
  /* These methods are currently only used for testing and debugging. */
  int sqlite3OsFileHandle(sqlite3_file *id){
    /* return id->pMethods->xFileHandle(id); */
    return 0;
  }

  sqlite3_vfs *pVfs = (sqlite3_vfs *)pAppData;
  return pVfs->xSleep(pVfs->pAppData, nMicro);
}
static int cfCurrentTime(void *pAppData, double *pTimeOut){
  sqlite3_vfs *pVfs = (sqlite3_vfs *)pAppData;
  return pVfs->xCurrentTime(pVfs->pAppData, pTimeOut);
}

static int processDevSymArgs(
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[],
  int *piDeviceChar,
  int *piSectorSize
){
  struct DeviceFlag {
    char *zName;
    int iValue;
  } aFlag[] = {
    { "atomic",      SQLITE_IOCAP_ATOMIC      },
    { "atomic512",   SQLITE_IOCAP_ATOMIC512   },
    { "atomic1k",    SQLITE_IOCAP_ATOMIC1K    },
    { "atomic2k",    SQLITE_IOCAP_ATOMIC2K    },
    { "atomic4k",    SQLITE_IOCAP_ATOMIC4K    },
    { "atomic8k",    SQLITE_IOCAP_ATOMIC8K    },
    { "atomic16k",   SQLITE_IOCAP_ATOMIC16K   },
    { "atomic32k",   SQLITE_IOCAP_ATOMIC32K   },
    { "atomic64k",   SQLITE_IOCAP_ATOMIC64K   },
    { "sequential",  SQLITE_IOCAP_SEQUENTIAL  },
    { "safe_append", SQLITE_IOCAP_SAFE_APPEND },
    { 0, 0 }
  };

  int i;
  int iDc = 0;
  int iSectorSize = 0;
  int setSectorsize = 0;
  int setDeviceChar = 0;

  for(i=0; i<objc; i+=2){
    int nOpt;
    char *zOpt = Tcl_GetStringFromObj(objv[i], &nOpt);

    if( (nOpt>11 || nOpt<2 || strncmp("-sectorsize", zOpt, nOpt)) 
     && (nOpt>16 || nOpt<2 || strncmp("-characteristics", zOpt, nOpt))
    ){
      Tcl_AppendResult(interp, 
        "Bad option: \"", zOpt, 
        "\" - must be \"-characteristics\" or \"-sectorsize\"", 0
      );
      return TCL_ERROR;
    }
    if( i==objc-1 ){
      Tcl_AppendResult(interp, "Option requires an argument: \"", zOpt, "\"",0);
      return TCL_ERROR;
    }

    if( zOpt[1]=='s' ){
      if( Tcl_GetIntFromObj(interp, objv[i+1], &iSectorSize) ){
        return TCL_ERROR;
      }
      setSectorsize = 1;
    }else{
      int j;
      Tcl_Obj **apObj;
      int nObj;
      if( Tcl_ListObjGetElements(interp, objv[i+1], &nObj, &apObj) ){
        return TCL_ERROR;
      }
      for(j=0; j<nObj; j++){
        int rc;
        int iChoice;
        Tcl_Obj *pFlag = Tcl_DuplicateObj(apObj[j]);
        Tcl_IncrRefCount(pFlag);
        Tcl_UtfToLower(Tcl_GetString(pFlag));
 
        rc = Tcl_GetIndexFromObjStruct(
            interp, pFlag, aFlag, sizeof(aFlag[0]), "no such flag", 0, &iChoice
        );
        Tcl_DecrRefCount(pFlag);
        if( rc ){
          return TCL_ERROR;
        }

        iDc |= aFlag[iChoice].iValue;
      }
      setDeviceChar = 1;
    }
  }

  if( setDeviceChar ){
    *piDeviceChar = iDc;
  }
  if( setSectorsize ){
    *piSectorSize = iSectorSize;
  }

  return TCL_OK;
}

/*
** tclcmd:   sqlite_crashparams ?OPTIONS? DELAY CRASHFILE
**
** This procedure implements a TCL command that enables crash testing
** in testfixture.  Once enabled, crash testing cannot be disabled.
**

*/
static int crashParamsObjCmd(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){

  int iDelay;
  const char *zCrashFile;
  int nCrashFile;

  static sqlite3_vfs crashVfs = {
    1,                  /* iVersion */
    0,                  /* szOsFile */

    crashVfs.pAppData = (void *)pOriginalVfs;
    crashVfs.szOsFile = sizeof(CrashFile) + pOriginalVfs->szOsFile;
    sqlite3_vfs_release(pOriginalVfs);
    /* sqlite3_vfs_unregister(pOriginalVfs); */
    sqlite3_vfs_register(&crashVfs, 1);
  }

  int iDc = -1;
  int iSectorSize = -1;





















  if( objc<3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?OPTIONS? DELAY CRASHFILE");
    goto error;
  }

  zCrashFile = Tcl_GetStringFromObj(objv[objc-1], &nCrashFile);
  if( nCrashFile>=sizeof(g.zCrashFile) ){
    Tcl_AppendResult(interp, "Filename is too long: \"", zCrashFile, "\"", 0);
    goto error;
  }
  if( Tcl_GetIntFromObj(interp, objv[objc-2], &iDelay) ){
    goto error;
  }




  if( processDevSymArgs(interp, objc-3, &objv[1], &iDc, &iSectorSize) ){













    return TCL_ERROR;



  }



















  if( iDc>=0 ){










    g.iDeviceCharacteristics = iDc;
  }
  if( iSectorSize>=0 ){
    g.iSectorSize = iSectorSize;
  }

  g.iCrash = iDelay;
  memcpy(g.zCrashFile, zCrashFile, nCrashFile+1);
  sqlite3CrashTestEnable = 1;
  return TCL_OK;

error:
  return TCL_ERROR;
}

static int devSymObjCmd(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){

  extern int sqlite3_test_device_characteristics;
  extern int sqlite3_test_sector_size;

  int iDc = -1;
  int iSectorSize = -1;
  if( processDevSymArgs(interp, objc-1, &objv[1], &iDc, &iSectorSize) ){
    return TCL_ERROR;
  }

  if( iDc>=0 ){
    sqlite3_test_device_characteristics = iDc;
  }
  if( iSectorSize>=0 ){
    sqlite3_test_sector_size = iSectorSize;
  }

  return TCL_OK;
}

#endif /* SQLITE_OMIT_DISKIO */

/*
** This procedure registers the TCL procedures defined in this file.
*/
int Sqlitetest6_Init(Tcl_Interp *interp){
#ifndef SQLITE_OMIT_DISKIO
  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "sqlite3_simulate_device", devSymObjCmd, 0, 0);
#endif
  return TCL_OK;
}

#endif /* SQLITE_TEST */

#
#***********************************************************************
#
# The focus of this file is testing some specific characteristics of the 
# IO traffic generated by SQLite (making sure SQLite is not writing out
# more database pages than it has to, stuff like that).
#
# $Id: io.test,v 1.3 2007/08/23 08:06:45 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Test summary:
#
# io-1.* -  Test that quick-balance does not journal pages unnecessarily.
# io-2.* -  Test that when the atomic-write optimisation is used no
#           journal file is created.
#           

set ::nWrite 0
proc nWrite {db} {
  set bt [btree_from_db $db]
  db_enter $db
  array set stats [btree_pager_stats $bt]
  db_leave $db
  set res [expr $stats(write) - $::nWrite]
  set ::nWrite $stats(write)
  set res
}

set ::nSync 0
proc nSync {} {
  set res [expr {$::sqlite_sync_count - $::nSync}]
  set ::nSync $::sqlite_sync_count
  set res
}

do_test io-1.1 {
  execsql {
    PRAGMA page_size = 1024;
    CREATE TABLE abc(a,b);
  }
  nWrite db

  lappend ret [nWrite db]
  execsql { INSERT INTO abc VALUES(7,randstr(230,230)); }
  lappend ret [nWrite db]
  execsql { INSERT INTO abc VALUES(8,randstr(230,230)); }
  lappend ret [nWrite db]
} {2 2 2}



# This insert should use the quick-balance trick to add a third leaf
# to the b-tree used to store table abc. It should only be necessary to
# write to 3 pages to do this: the change-counter, the root-page and
# the new leaf page.
do_test io-1.5 {
  execsql { INSERT INTO abc VALUES(9,randstr(230,230)); }
  nWrite db
} {3}



#----------------------------------------------------------------------
# Test cases io-2.* test the atomic-write optimization.
#
do_test io-2.1 {
  execsql { DELETE FROM abc; VACUUM; }
} {}

# Clear the write and sync counts.
nWrite db ; nSync

# The following INSERT updates 2 pages and requires 4 calls to fsync():
#
#   1) The directory in which the journal file is created,
#   2) The journal file (to sync the page data),
#   3) The journal file (to sync the journal file header),
#   4) The database file.
#
do_test io-2.2 {
  execsql { INSERT INTO abc VALUES(1, 2) }
  list [nWrite db] [nSync]
} {2 4}

# Set the device-characteristic mask to include the SQLITE_IOCAP_ATOMIC,
# then do another INSERT similar to the one in io-2.2. This should
# only write 1 page and require a single fsync().
# 
# The single fsync() is the database file. Only one page is reported as
# written because page 1 - the change-counter page - is written using
# an out-of-band method that bypasses the write counter.
#
sqlite3_simulate_device -char atomic
do_test io-2.3 {
  execsql { INSERT INTO abc VALUES(3, 4) }
  list [nWrite db] [nSync]
} {1 1}

# Test that the journal file is not created and the change-counter is
# updated when the atomic-write optimization is used.
#
do_test io-2.4.1 {
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(5, 6);
  }
  sqlite3 db2 test.db
  execsql { SELECT * FROM abc } db2
} {1 2 3 4}
do_test io-2.4.2 {
  file exists test.db-journal
} {0}
do_test io-2.4.3 {
  execsql { COMMIT }
  execsql { SELECT * FROM abc } db2
} {1 2 3 4 5 6}
db2 close

# Test that the journal file is created and sync()d if the transaction
# modifies more than one database page, even if the IOCAP_ATOMIC flag
# is set.
#
do_test io-2.5.1 {
  execsql { CREATE TABLE def(d, e) }
  nWrite db ; nSync
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(7, 8);
  }
  file exists test.db-journal
} {0}
do_test io-2.5.2 {
  execsql { INSERT INTO def VALUES('a', 'b'); }
  file exists test.db-journal
} {1}
do_test io-2.5.3 {
  execsql { COMMIT }
  list [nWrite db] [nSync]
} {3 4}

# Test that the journal file is created and sync()d if the transaction
# modifies a single database page and also appends a page to the file.
# Internally, this case is handled differently to the one above. The
# journal file is not actually created until the 'COMMIT' statement
# is executed.
#
do_test io-2.6.1 {
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(9, randstr(1000,1000));
  }
  file exists test.db-journal
} {0}
do_test io-2.6.2 {
  # Create a file at "test.db-journal". This will prevent SQLite from
  # opening the journal for exclusive access. As a result, the COMMIT
  # should fail with SQLITE_CANTOPEN and the transaction rolled back.
  #
  set fd [open test.db-journal w]
  puts $fd "This is not a journal file"
  close $fd
  catchsql { COMMIT }
} {1 {unable to open database file}}
do_test io-2.6.3 {
  file delete -force test.db-journal
  catchsql { COMMIT }
} {1 {cannot commit - no transaction is active}}
do_test io-2.6.4 {
  execsql { SELECT * FROM abc }
} {1 2 3 4 5 6 7 8}


# Test that if the database modification is part of multi-file commit,
# the journal file is always created. In this case, the journal file
# is created during execution of the COMMIT statement, so we have to
# use the same technique to check that it is created as in the above 
# block.
file delete -force test2.db test2.db-journal
do_test io-2.7.1 {
  execsql {
    ATTACH 'test2.db' AS aux;
    CREATE TABLE aux.abc2(a, b);
    BEGIN;
    INSERT INTO abc VALUES(9, 10);
  }
  file exists test.db-journal
} {0}
do_test io-2.7.2 {
  execsql { INSERT INTO abc2 SELECT * FROM abc }
  file exists test2.db-journal
} {0}
do_test io-2.7.3 {
  execsql { SELECT * FROM abc UNION ALL SELECT * FROM abc2 }
} {1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10}
do_test io-2.7.4 {
  set fd [open test2.db-journal w]
  puts $fd "This is not a journal file"
  close $fd
  catchsql { COMMIT }
} {1 {unable to open database file}}
do_test io-2.7.5 {
  file delete -force test2.db-journal
  catchsql { COMMIT }
} {1 {cannot commit - no transaction is active}}
do_test io-2.7.6 {
  execsql { SELECT * FROM abc UNION ALL SELECT * FROM abc2 }
} {1 2 3 4 5 6 7 8}

# Try an explicit ROLLBACK before the journal file is created.
#
do_test io-2.8.1 {
  execsql {
    BEGIN;
    DELETE FROM abc;
  }
  file exists test.db-journal
} {0}
do_test io-2.8.2 {
  execsql { SELECT * FROM abc }
} {}
do_test io-2.8.3 {
  execsql {
    ROLLBACK;
    SELECT * FROM abc;
  }
} {1 2 3 4 5 6 7 8}

sqlite3_simulate_device -char {} -sectorsize 0

finish_test