SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.333 2007/04/06 01:04:40 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

  }

  sqliteFree(sAggInfo.aCol);
  sqliteFree(sAggInfo.aFunc);
  return rc;
}

#if defined(SQLITE_DEBUG)
/*
*******************************************************************************
** The following code is used for testing and debugging only.  The code
** that follows does not appear in normal builds.
**
** These routines are used to print out the content of all or part of a 
** parse structures such as Select or Expr.  Such printouts are useful

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.246 2007/04/06 01:04:40 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)

/*
** Two routines for printing the content of an sqlite3_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
** are no-ops.
*/
#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_DEBUG)

static void TRACE_IDX_INPUTS(sqlite3_index_info *p){
  int i;
  if( !sqlite3_where_trace ) return;
  for(i=0; i<p->nConstraint; i++){
    sqlite3DebugPrintf("  constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
       i,
       p->aConstraint[i].iColumn,

#
#***********************************************************************
#
# The focus of the tests in this file are IO errors that occur in a shared
# cache context. What happens to connection B if one connection A encounters
# an IO-error whilst reading or writing the file-system?
#
# $Id: shared_err.test,v 1.11 2007/04/06 01:04:40 drh Exp $

proc skip {args} {}


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

    expr {
      ($::steprc eq "SQLITE_ROW" && $::column eq "002.002.002.002.002") ||
      ($::steprc eq "SQLITE_ERROR" && $::column eq "") ||
      ($::steprc eq "SQLITE_ABORT" && $::column eq "001.001.001.001.001") 
    }
  } {1}
  do_test shared_ioerr-3.$n.cleanup.3 {
    expr {
      ($::steprc eq "SQLITE_ROW" && $::finalrc eq "SQLITE_OK") ||
      ($::steprc eq "SQLITE_ERROR" && $::finalrc eq "SQLITE_IOERR") ||
      ($::steprc eq "SQLITE_ABORT" && $::finalrc eq "SQLITE_OK")
    }
  } {1}

# db2 eval {select * from sqlite_master}
  db2 close
}

# This is a repeat of the previous test except that this time we
# are doing a reverse-order scan of the table when the cursor is
# "saved".
# 
do_ioerr_test shared_ioerr-3rev -tclprep {
  sqlite3 db2 test.db
  execsql {
    PRAGMA read_uncommitted = 1;
    PRAGMA cache_size = 10;
    BEGIN;
    CREATE TABLE t1(a, b, UNIQUE(a, b));
  } db2
  for {set i 0} {$i < 200} {incr i} {
    set a [string range [string repeat "[format %03d $i]." 5] 0 end-1]

    set b [string repeat $i 2000]
    execsql {INSERT INTO t1 VALUES($a, $b)} db2
  }
  execsql {COMMIT} db2
  set ::DB2 [sqlite3_connection_pointer db2]
  set ::STMT [sqlite3_prepare $::DB2 \
           "SELECT a FROM t1 ORDER BY a DESC" -1 DUMMY]
  sqlite3_step $::STMT       ;# Cursor points at 199.199.199.199.199
  sqlite3_step $::STMT       ;# Cursor points at 198.198.198.198.198

} -tclbody {
  execsql {
    BEGIN;
    INSERT INTO t1 VALUES('201.201.201.201.201', NULL);
    UPDATE t1 SET a = '202.202.202.202.202' WHERE a LIKE '201%';
    COMMIT;
  }
} -cleanup {
  set ::steprc  [sqlite3_step $::STMT]
  set ::column  [sqlite3_column_text $::STMT 0]
  set ::finalrc [sqlite3_finalize $::STMT]

  # There are three possible outcomes here (assuming persistent IO errors):
  #
  # 1. If the [sqlite3_step] did not require any IO (required pages in
  #    the cache), then the next row ("002...") may be retrieved 
  #    successfully.
  #
  # 2. If the [sqlite3_step] does require IO, then [sqlite3_step] returns
  #    SQLITE_ERROR and [sqlite3_finalize] returns IOERR.
  #
  # 3. If, after the initial IO error, SQLite tried to rollback the
  #    active transaction and a second IO error was encountered, then
  #    statement $::STMT will have been aborted. This means [sqlite3_stmt]
  #    returns SQLITE_ABORT, and the statement cursor does not move. i.e.
  #    [sqlite3_column] still returns the current row ("001...") and
  #    [sqlite3_finalize] returns SQLITE_OK.
  #

  do_test shared_ioerr-3rev.$n.cleanup.1 {
    expr {
      $::steprc eq "SQLITE_ROW" || 
      $::steprc eq "SQLITE_ERROR" ||
      $::steprc eq "SQLITE_ABORT" 
    }
  } {1}
  do_test shared_ioerr-3rev.$n.cleanup.2 {
    expr {
      ($::steprc eq "SQLITE_ROW" && $::column eq "197.197.197.197.197") ||
      ($::steprc eq "SQLITE_ERROR" && $::column eq "") ||
      ($::steprc eq "SQLITE_ABORT" && $::column eq "198.198.198.198.198") 
    }
  } {1}
  do_test shared_ioerr-3rev.$n.cleanup.3 {
    expr {
      ($::steprc eq "SQLITE_ROW" && $::finalrc eq "SQLITE_OK") ||
      ($::steprc eq "SQLITE_ERROR" && $::finalrc eq "SQLITE_IOERR") ||
      ($::steprc eq "SQLITE_ABORT" && $::finalrc eq "SQLITE_OK")
    }
  } {1}