** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.619 2009/07/25 00:13:59 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
*/
int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize, int nReserve){
  int rc = pPager->errCode;

  if( rc==SQLITE_OK ){
    u16 pageSize = *pPageSize;
    assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );
    if( pageSize && pageSize!=pPager->pageSize 
     && (pPager->memDb==0 || pPager->dbSize==0)
     && sqlite3PcacheRefCount(pPager->pPCache)==0 

    ){
      char *pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ){
        rc = SQLITE_NOMEM;
      }else{
        pager_reset(pPager);
        pPager->pageSize = pageSize;
................................................................................
      rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
    }
  }
  if( rc==SQLITE_OK ){
    pPager->nSubRec++;
    assert( pPager->nSavepoint>0 );
    rc = addToSavepointBitvecs(pPager, pPg->pgno);
    testcase( rc!=SQLITE_OK );
  }
  return rc;
}


/*
** This function is called by the pcache layer when it has reached some
................................................................................
  **
  ** The solution is to write the current data for page X into the 
  ** sub-journal file now (if it is not already there), so that it will
  ** be restored to its current value when the "ROLLBACK TO sp" is 
  ** executed.
  */
  if( rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg) ){

    rc = subjournalPage(pPg);
  }

  /* Write the contents of the page out to the database file. */
  if( rc==SQLITE_OK ){
    pPg->pDirty = 0;
    rc = pager_write_pagelist(pPg);
................................................................................
  int rc;                       /* Return code */
  int exists;                   /* True if a journal file is present */

  assert( pPager!=0 );
  assert( pPager->useJournal );
  assert( isOpen(pPager->fd) );
  assert( !isOpen(pPager->jfd) );


  *pExists = 0;
  rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
  if( rc==SQLITE_OK && exists ){
    int locked;                 /* True if some process holds a RESERVED lock */

    /* Race condition here:  Another process might have been holding the
................................................................................
      ** a RESERVED lock to avoid race conditions and to avoid violating
      ** [H33020].
      */
      rc = sqlite3PagerPagecount(pPager, &nPage);
      if( rc==SQLITE_OK ){
        if( nPage==0 ){
          sqlite3BeginBenignMalloc();
          if( pPager->state>=PAGER_RESERVED
                 ||  sqlite3OsLock(pPager->fd, RESERVED_LOCK)==SQLITE_OK ){
            sqlite3OsDelete(pVfs, pPager->zJournal, 0);
            assert( pPager->state>=PAGER_SHARED );
            if( pPager->state==PAGER_SHARED ){
              sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
            }
          }
          sqlite3EndBenignMalloc();
        }else{
          /* The journal file exists and no other connection has a reserved
          ** or greater lock on the database file. Now check that there is
          ** at least one non-zero bytes at the start of the journal file.
          ** If there is, then we consider this journal to be hot. If not, 
................................................................................
** IO error occurs while locking the database, checking for a hot-journal
** file or rolling back a journal file, the IO error code is returned.
*/
int sqlite3PagerSharedLock(Pager *pPager){
  int rc = SQLITE_OK;                /* Return code */
  int isErrorReset = 0;              /* True if recovering from error state */


  /* If this database has no outstanding page references and is in an 
  ** error-state, this is a chance to clear the error. Discard the 



  ** contents of the pager-cache and rollback any hot journal in the
  ** file-system.
  */
  if( !MEMDB && sqlite3PcacheRefCount(pPager->pPCache)==0 && pPager->errCode ){
    if( isOpen(pPager->jfd) || pPager->zJournal ){
      isErrorReset = 1;
    }
    pPager->errCode = SQLITE_OK;
    pager_reset(pPager);
  }

................................................................................
    }
    assert( pPager->state>=SHARED_LOCK );

    /* If a journal file exists, and there is no RESERVED lock on the
    ** database file, then it either needs to be played back or deleted.
    */
    if( !isErrorReset ){

      rc = hasHotJournal(pPager, &isHotJournal);
      if( rc!=SQLITE_OK ){
        goto failed;
      }
    }
    if( isErrorReset || isHotJournal ){
      /* Get an EXCLUSIVE lock on the database file. At this point it is
................................................................................
        /* Failure to set the bits in the InJournal bit-vectors is benign.
        ** It merely means that we might do some extra work to journal a 
        ** page that does not need to be journaled.  Nevertheless, be sure 
        ** to test the case where a malloc error occurs while trying to set 
        ** a bit in a bit vector.
        */
        sqlite3BeginBenignMalloc();
        if( ALWAYS(pgno<=pPager->dbOrigSize) ){
          TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
          testcase( rc==SQLITE_NOMEM );
        }
        TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
        testcase( rc==SQLITE_NOMEM );
        sqlite3EndBenignMalloc();
      }else{
................................................................................
    pPager->aSavepoint = aNew;
    pPager->nSavepoint = nSavepoint;

    /* Populate the PagerSavepoint structures just allocated. */
    for(ii=nCurrent; ii<nSavepoint; ii++){
      assert( pPager->dbSizeValid );
      aNew[ii].nOrig = pPager->dbSize;
      if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
        aNew[ii].iOffset = pPager->journalOff;
      }else{
        aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
      }
      aNew[ii].iSubRec = pPager->nSubRec;
      aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
      if( !aNew[ii].pInSavepoint ){

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.620 2009/07/25 04:12:02 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
*/
int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize, int nReserve){
  int rc = pPager->errCode;

  if( rc==SQLITE_OK ){
    u16 pageSize = *pPageSize;
    assert( pageSize==0 || (pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE) );

    if( (pPager->memDb==0 || pPager->dbSize==0)
     && sqlite3PcacheRefCount(pPager->pPCache)==0 
     && pageSize && pageSize!=pPager->pageSize 
    ){
      char *pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ){
        rc = SQLITE_NOMEM;
      }else{
        pager_reset(pPager);
        pPager->pageSize = pageSize;
................................................................................
      rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
    }
  }
  if( rc==SQLITE_OK ){
    pPager->nSubRec++;
    assert( pPager->nSavepoint>0 );
    rc = addToSavepointBitvecs(pPager, pPg->pgno);

  }
  return rc;
}


/*
** This function is called by the pcache layer when it has reached some
................................................................................
  **
  ** The solution is to write the current data for page X into the 
  ** sub-journal file now (if it is not already there), so that it will
  ** be restored to its current value when the "ROLLBACK TO sp" is 
  ** executed.
  */
  if( rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg) ){
assert(0);
    rc = subjournalPage(pPg);
  }

  /* Write the contents of the page out to the database file. */
  if( rc==SQLITE_OK ){
    pPg->pDirty = 0;
    rc = pager_write_pagelist(pPg);
................................................................................
  int rc;                       /* Return code */
  int exists;                   /* True if a journal file is present */

  assert( pPager!=0 );
  assert( pPager->useJournal );
  assert( isOpen(pPager->fd) );
  assert( !isOpen(pPager->jfd) );
  assert( pPager->state <= PAGER_SHARED );

  *pExists = 0;
  rc = sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS, &exists);
  if( rc==SQLITE_OK && exists ){
    int locked;                 /* True if some process holds a RESERVED lock */

    /* Race condition here:  Another process might have been holding the
................................................................................
      ** a RESERVED lock to avoid race conditions and to avoid violating
      ** [H33020].
      */
      rc = sqlite3PagerPagecount(pPager, &nPage);
      if( rc==SQLITE_OK ){
        if( nPage==0 ){
          sqlite3BeginBenignMalloc();

          if( sqlite3OsLock(pPager->fd, RESERVED_LOCK)==SQLITE_OK ){
            sqlite3OsDelete(pVfs, pPager->zJournal, 0);


            sqlite3OsUnlock(pPager->fd, SHARED_LOCK);

          }
          sqlite3EndBenignMalloc();
        }else{
          /* The journal file exists and no other connection has a reserved
          ** or greater lock on the database file. Now check that there is
          ** at least one non-zero bytes at the start of the journal file.
          ** If there is, then we consider this journal to be hot. If not, 
................................................................................
** IO error occurs while locking the database, checking for a hot-journal
** file or rolling back a journal file, the IO error code is returned.
*/
int sqlite3PagerSharedLock(Pager *pPager){
  int rc = SQLITE_OK;                /* Return code */
  int isErrorReset = 0;              /* True if recovering from error state */

  /* This routine is only called from b-tree and only when there are no
  ** outstanding pages */

  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );

  /* If this database is in an error-state, now is a chance to clear
  ** the error. Discard the contents of the pager-cache and rollback
  ** any hot journal in the file-system.
  */
  if( !MEMDB && pPager->errCode ){
    if( isOpen(pPager->jfd) || pPager->zJournal ){
      isErrorReset = 1;
    }
    pPager->errCode = SQLITE_OK;
    pager_reset(pPager);
  }

................................................................................
    }
    assert( pPager->state>=SHARED_LOCK );

    /* If a journal file exists, and there is no RESERVED lock on the
    ** database file, then it either needs to be played back or deleted.
    */
    if( !isErrorReset ){
      assert( pPager->state <= PAGER_SHARED );
      rc = hasHotJournal(pPager, &isHotJournal);
      if( rc!=SQLITE_OK ){
        goto failed;
      }
    }
    if( isErrorReset || isHotJournal ){
      /* Get an EXCLUSIVE lock on the database file. At this point it is
................................................................................
        /* Failure to set the bits in the InJournal bit-vectors is benign.
        ** It merely means that we might do some extra work to journal a 
        ** page that does not need to be journaled.  Nevertheless, be sure 
        ** to test the case where a malloc error occurs while trying to set 
        ** a bit in a bit vector.
        */
        sqlite3BeginBenignMalloc();
        if( pgno<=pPager->dbOrigSize ){
          TESTONLY( rc = ) sqlite3BitvecSet(pPager->pInJournal, pgno);
          testcase( rc==SQLITE_NOMEM );
        }
        TESTONLY( rc = ) addToSavepointBitvecs(pPager, pgno);
        testcase( rc==SQLITE_NOMEM );
        sqlite3EndBenignMalloc();
      }else{
................................................................................
    pPager->aSavepoint = aNew;
    pPager->nSavepoint = nSavepoint;

    /* Populate the PagerSavepoint structures just allocated. */
    for(ii=nCurrent; ii<nSavepoint; ii++){
      assert( pPager->dbSizeValid );
      aNew[ii].nOrig = pPager->dbSize;
      if( isOpen(pPager->jfd) && ALWAYS(pPager->journalOff>0) ){
        aNew[ii].iOffset = pPager->journalOff;
      }else{
        aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
      }
      aNew[ii].iSubRec = pPager->nSubRec;
      aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
      if( !aNew[ii].pInSavepoint ){

# 2001 September 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 script is page cache subsystem.
#
# $Id: pager.test,v 1.36 2009/07/24 16:32:01 drh Exp $


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

if {[info commands pager_open]!=""} {
db close

# Basic sanity check.  Open and close a pager.
#
do_test pager-1.0 {
  catch {file delete -force ptf1.db}
  catch {file delete -force ptf1.db-journal}
  set v [catch {
    set ::p1 [pager_open ptf1.db 10]
  } msg]
} {0}
do_test pager-1.1 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size -1 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager-1.2 {
  pager_pagecount $::p1
} {0}
do_test pager-1.3 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size -1 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager-1.4 {
  pager_close $::p1
} {}

# Try to write a few pages.
#
do_test pager-2.1 {
  set v [catch {
    set ::p1 [pager_open ptf1.db 10]
  } msg]
} {0}
#do_test pager-2.2 {
#  set v [catch {
#    set ::g1 [page_get $::p1 0]
#  } msg]
#  lappend v $msg
#} {1 SQLITE_ERROR}
#do_test pager-2.3.1 {
#  set ::gx [page_lookup $::p1 1]
#} {}
do_test pager-2.3.2 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size -1 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager-2.3.3 {
  set v [catch {
    set ::g1 [page_get $::p1 1]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager-2.3.3 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager-2.3.4 {
  set ::gx [page_lookup $::p1 1]
  expr {$::gx!=""}
} {1}
do_test pager-2.3.5 {
  page_unref $::gx
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager-2.3.6 {
  expr {$::g1==$::gx}
} {1}
do_test pager-2.3.7 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager-2.4 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager-2.5 {
  pager_pagecount $::p1
} {0}
do_test pager-2.6 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 0 miss 1 ovfl 0}
do_test pager-2.7 {
  page_number $::g1
} {1}
do_test pager-2.8 {
  page_read $::g1
} {}
do_test pager-2.9 {
  page_unref $::g1
} {}

# Update 24/03/2007: Even though the ref-count has dropped to zero, the
# pager-cache still contains some pages. Previously, it was always true
# that if there were no references to a pager it was empty.
do_test pager-2.10 {
  pager_stats $::p1
} {ref 0 page 1 max 10 size -1 state 0 err 0 hit 0 miss 1 ovfl 0}
do_test pager-2.11 {
  set ::g1 [page_get $::p1 1]
  expr {$::g1!=0}
} {1}
do_test pager-2.12 {
  page_number $::g1
} {1}
do_test pager-2.13 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 1 err 0 hit 1 miss 1 ovfl 0}
do_test pager-2.14 {
  set v [catch {
    page_write $::g1 "Page-One"
  } msg]
  lappend v $msg
} {0 {}}
do_test pager-2.15 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 2 err 0 hit 1 miss 1 ovfl 0}
do_test pager-2.16 {
  page_read $::g1
} {Page-One}
do_test pager-2.17 {
  set v [catch {
    pager_commit $::p1
  } msg]
  lappend v $msg
} {0 {}}
do_test pager-2.20 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size -1 state 1 err 0 hit 2 miss 1 ovfl 0}
do_test pager-2.19 {
  pager_pagecount $::p1
} {1}
do_test pager-2.21 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 1 err 0 hit 2 miss 1 ovfl 0}
do_test pager-2.22 {
  page_unref $::g1
} {}
do_test pager-2.23 {
  pager_stats $::p1
} {ref 0 page 1 max 10 size -1 state 0 err 0 hit 2 miss 1 ovfl 0}
do_test pager-2.24 {
  set v [catch {
    page_get $::p1 1
  } ::g1]
  if {$v} {lappend v $::g1}
  set v
} {0}
do_test pager-2.25 {
  page_read $::g1
} {Page-One}
do_test pager-2.26 {
  set v [catch {
    page_write $::g1 {page-one}
  } msg]
  lappend v $msg
} {0 {}}
do_test pager-2.27 {
  page_read $::g1
} {page-one}
do_test pager-2.28 {
  set v [catch {
    pager_rollback $::p1
  } msg]
  lappend v $msg
} {0 {}}
do_test pager-2.29 {
  page_unref $::g1
  set ::g1 [page_get $::p1 1]
  page_read $::g1
} {Page-One}
do_test pager-2.99 {
  page_unref $::g1
  pager_close $::p1
} {}

do_test pager-3.1 {
  set v [catch {
    set ::p1 [pager_open ptf1.db 15]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager-3.2 {
  pager_pagecount $::p1
} {1}
do_test pager-3.3 {
  set v [catch {
    set ::g(1) [page_get $::p1 1]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager-3.4 {
  page_read $::g(1)
} {Page-One}
do_test pager-3.5 {
  for {set i 2} {$i<=20} {incr i} {
    set gx [page_get $::p1 $i]
    page_write $gx "Page-$i"
    page_unref $gx
  }
  pager_commit $::p1
  page_unref $::g(1)
} {}
for {set i 2} {$i<=20} {incr i} {
  do_test pager-3.6.[expr {$i-1}] [subst {
    set gx \[page_get $::p1 $i\]
    set v \[page_read \$gx\]
    page_unref \$gx
    set v
  }] "Page-$i"
}
for {set i 1} {$i<=20} {incr i} {
  regsub -all CNT {
    set ::g1 [page_get $::p1 CNT]
    set ::g2 [page_get $::p1 CNT]
    set ::vx [page_read $::g2]
    expr {$::g1==$::g2}
  } $i body;
  do_test pager-3.7.$i.1 $body {1}
  regsub -all CNT {
    page_unref $::g2
    set vy [page_read $::g1]
    expr {$vy==$::vx}
  } $i body;
  do_test pager-3.7.$i.2 $body {1}
  regsub -all CNT {
    page_unref $::g1
    set gx [page_get $::p1 CNT]
    set vy [page_read $gx]
    page_unref $gx
    expr {$vy==$::vx}
  } $i body;
  do_test pager-3.7.$i.3 $body {1}
}
do_test pager-3.99 {
  pager_close $::p1
} {}

# tests of the checkpoint mechanism and api
#
do_test pager-4.0 {
  set v [catch {
    file delete -force ptf1.db
    set ::p1 [pager_open ptf1.db 15]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager-4.1 {
  set g1 [page_get $::p1 1]
  page_write $g1 "Page-1 v0"
  for {set i 2} {$i<=20} {incr i} {
    set gx [page_get $::p1 $i]
    page_write $gx "Page-$i v0"
    page_unref $gx
  }
  pager_commit $::p1
} {}
for {set i 1} {$i<=20} {incr i} {
  do_test pager-4.2.$i {
    set gx [page_get $p1 $i]
    set v [page_read $gx]
    page_unref $gx
    set v
  } "Page-$i v0"
}
do_test pager-4.3 {
  lrange [pager_stats $::p1] 0 1
} {ref 1}
do_test pager-4.4 {
  lrange [pager_stats $::p1] 8 9
} {state 1}

for {set i 1} {$i<20} {incr i} {
  do_test pager-4.5.$i.0 {
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v[expr {$i-1}]"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager-4.5.$i.1 {
    page_write $g1 "Page-1 v$i"
    lrange [pager_stats $p1] 8 9
  } {state 2}
  do_test pager-4.5.$i.2 {
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      page_write $gx "Page-$j v$i"
      page_unref $gx
      if {$j==$i} {
        pager_stmt_begin $p1
      }
    }
  } {}
  do_test pager-4.5.$i.3 {
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v$i"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager-4.5.$i.4 {
    pager_rollback $p1
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v[expr {$i-1}]"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager-4.5.$i.5 {
    page_write $g1 "Page-1 v$i"
    lrange [pager_stats $p1] 8 9
  } {state 2}
  do_test pager-4.5.$i.6 {
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      page_write $gx "Page-$j v$i"
      page_unref $gx
      if {$j==$i} {
        pager_stmt_begin $p1
      }
    }
  } {}
  do_test pager-4.5.$i.7 {
    pager_stmt_rollback $p1
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      if {$j<=$i || $i==1} {
        set shouldbe "Page-$j v$i"
      } else {
        set shouldbe "Page-$j v[expr {$i-1}]"
      }
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager-4.5.$i.8 {
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      page_write $gx "Page-$j v$i"
      page_unref $gx
      if {$j==$i} {
        pager_stmt_begin $p1
      }
    }
  } {}
  do_test pager-4.5.$i.9 {
    pager_stmt_commit $p1
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v$i"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager-4.5.$i.10 {
    pager_commit $p1
    lrange [pager_stats $p1] 8 9
  } {state 1}
}

# Test that nothing bad happens when sqlite3pager_set_cachesize() is
# called with a negative argument.
do_test pager-4.6.1 {
  pager_close [pager_open ptf2.db -15]
} {}

# Test truncate on an in-memory database is Ok.
ifcapable memorydb {
  do_test pager-4.6.2 {
    set ::p2 [pager_open :memory: 10]
    pager_truncate $::p2 0
  } {}
  do_test pager-4.6.3 {
    set page1 [page_get $::p2 1]
    for {set i 1} {$i<5} {incr i} {
      set p [page_get $::p2 $i]
      page_write $p "Page $i"
      pager_commit $::p2
      page_unref $p
    }
    page_unref $page1
    pager_truncate $::p2 3
  } {}
  do_test pager-4.6.4 {
    pager_close $::p2
  } {}
}

do_test pager-4.99 {
  page_unref $::g1
  pager_close $::p1
} {}



  file delete -force ptf1.db

} ;# end if( not mem: and has pager_open command );

if 0 {
# Ticket #615: an assertion fault inside the pager.  It is a benign
# fault, but we might as well test for it.
#
do_test pager-5.1 {
  sqlite3 db test.db
  execsql {
    BEGIN;
    CREATE TABLE t1(x);
    PRAGMA synchronous=off;
    COMMIT;
  }
} {}
}

# The following tests cover rolling back hot journal files. 
# They can't be run on windows because the windows version of 
# SQLite holds a mandatory exclusive lock on journal files it has open.
# 
# They cannot be run during the journaltest permutation because 
# "PRAGMA synchronous = 0" is used.
#
if {$tcl_platform(platform)!="windows" && (
      0 == [info exists ::permutations_test_prefix] 
   || $::permutations_test_prefix ne "journaltest"
)} {
do_test pager-6.1 {
  file delete -force test2.db
  file delete -force test2.db-journal
  sqlite3 db2 test2.db
  execsql {
    PRAGMA synchronous = 0;
    CREATE TABLE abc(a, b, c);
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    INSERT INTO abc VALUES(1, 2, randstr(200,200));
    BEGIN;
    UPDATE abc SET c = randstr(200,200);
  } db2
  copy_file test2.db test.db
  copy_file test2.db-journal test.db-journal

  set f [open test.db-journal a]
  fconfigure $f -encoding binary
  seek $f [expr [file size test.db-journal] - 1032] start
  puts -nonewline $f "\00\00\00\00"
  close $f

  sqlite3 db test.db
  execsql {
    SELECT sql FROM sqlite_master
  }
} {{CREATE TABLE abc(a, b, c)}}

do_test pager-6.2 {
  copy_file test2.db test.db
  copy_file test2.db-journal test.db-journal

  set f [open test.db-journal a]
  fconfigure $f -encoding binary
  seek $f [expr [file size test.db-journal] - 1032] start
  puts -nonewline $f "\00\00\00\FF"
  close $f

  sqlite3 db test.db
  execsql {
    SELECT sql FROM sqlite_master
  }
} {{CREATE TABLE abc(a, b, c)}}

do_test pager-6.3 {
  copy_file test2.db test.db
  copy_file test2.db-journal test.db-journal

  set f [open test.db-journal a]
  fconfigure $f -encoding binary
  seek $f [expr [file size test.db-journal] - 4] start
  puts -nonewline $f "\00\00\00\00"
  close $f

  sqlite3 db test.db
  execsql {
    SELECT sql FROM sqlite_master
  }
} {{CREATE TABLE abc(a, b, c)}}

do_test pager-6.4.1 {
  execsql {
    BEGIN;
    SELECT sql FROM sqlite_master;
  }
  copy_file test2.db-journal test.db-journal;
  sqlite3 db3 test.db
  catchsql {
    BEGIN;
    SELECT sql FROM sqlite_master;
  } db3;
} {1 {database is locked}}
do_test pager-6.4.2 {
  file delete -force test.db-journal
  catchsql {
    SELECT sql FROM sqlite_master;
  } db3;
} {0 {{CREATE TABLE abc(a, b, c)}}}
do_test pager-6.4.3 {
  db3 close
  execsql {
    COMMIT;
  }
} {}

do_test pager-6.5 {
  copy_file test2.db test.db
  copy_file test2.db-journal test.db-journal

  set f [open test.db-journal a]
  fconfigure $f -encoding binary
  puts -nonewline $f "hello"
  puts -nonewline $f "\x00\x00\x00\x05\x01\x02\x03\x04"
  puts -nonewline $f "\xd9\xd5\x05\xf9\x20\xa1\x63\xd7"
  close $f

  sqlite3 db test.db
  execsql {
    SELECT sql FROM sqlite_master
  }
} {{CREATE TABLE abc(a, b, c)}}

do_test pager-6.5 {
  db2 close
} {}
}
finish_test

# 2001 September 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 script is page cache subsystem.
#
# $Id: pager2.test,v 1.9 2008/12/30 17:55:00 drh Exp $


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

# Don't run this test file if the pager test interface [pager_open] is not
# available, or the library was compiled without in-memory database support.
#
if {[info commands pager_open]!=""} {
ifcapable memorydb {
db close

# Basic sanity check.  Open and close a pager.
#
do_test pager2-1.0 {
  set v [catch {
    set ::p1 [pager_open :memory: 10]
  } msg]
} {0}
do_test pager2-1.1 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size 0 state 4 err 0 hit 0 miss 0 ovfl 0}
do_test pager2-1.2 {
  pager_pagecount $::p1
} {0}
do_test pager2-1.3 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size 0 state 4 err 0 hit 0 miss 0 ovfl 0}
do_test pager2-1.4 {
  pager_close $::p1
} {}

# Try to write a few pages.
#
do_test pager2-2.1 {
  set v [catch {
    set ::p1 [pager_open :memory: 10]
  } msg]
} {0}
#do_test pager2-2.2 {
#  set v [catch {
#    set ::g1 [page_get $::p1 0]
#  } msg]
#  lappend v $msg
#} {1 SQLITE_ERROR}
do_test pager2-2.3.1 {
  set ::gx [page_lookup $::p1 1]
} {}
do_test pager2-2.3.2 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size 0 state 4 err 0 hit 0 miss 0 ovfl 0}
do_test pager2-2.3.3 {
  set v [catch {
    set ::g1 [page_get $::p1 1]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager2-2.3.3 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 4 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.3.4 {
  set ::gx [page_lookup $::p1 1]
  page_unref $::gx
  expr {$::gx!=""}
} {1}
do_test pager2-2.3.5 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 4 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.3.6 {
  expr {$::g1==$::gx}
} {1}
do_test pager2-2.3.7 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 4 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.4 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 4 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.5 {
  pager_pagecount $::p1
} {0}
do_test pager2-2.6 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 4 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.7 {
  page_number $::g1
} {1}
do_test pager2-2.8 {
  page_read $::g1
} {}
do_test pager2-2.9 {
  page_unref $::g1
} {}
do_test pager2-2.10 {
  pager_stats $::p1
} {ref 0 page 1 max 10 size 0 state 4 err 0 hit 0 miss 1 ovfl 0}
do_test pager2-2.11 {
  set ::g1 [page_get $::p1 1]
  expr {$::g1!=0}
} {1}
do_test pager2-2.12 {
  page_number $::g1
} {1}
do_test pager2-2.13 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 0 state 4 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.14 {
  set v [catch {
    page_write $::g1 "Page-One"
  } msg]
  lappend v $msg
} {0 {}}
do_test pager2-2.15 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 4 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.16 {
  page_read $::g1
} {Page-One}
do_test pager2-2.17 {
  set v [catch {
    pager_commit $::p1
  } msg]
  lappend v $msg
} {0 {}}
do_test pager2-2.20 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 4 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.19 {
  pager_pagecount $::p1
} {1}
do_test pager2-2.21 {
  pager_stats $::p1
} {ref 1 page 1 max 10 size 1 state 4 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.22 {
  page_unref $::g1
} {}
do_test pager2-2.23 {
  pager_stats $::p1
} {ref 0 page 1 max 10 size 1 state 4 err 0 hit 1 miss 1 ovfl 0}
do_test pager2-2.24 {
  set v [catch {
    page_get $::p1 1
  } ::g1]
  if {$v} {lappend v $::g1}
  set v
} {0}
do_test pager2-2.25 {
  page_read $::g1
} {Page-One}
do_test pager2-2.26 {
  set v [catch {
    page_write $::g1 {page-one}
  } msg]
  lappend v $msg
} {0 {}}
do_test pager2-2.27 {
  page_read $::g1
} {page-one}
do_test pager2-2.28 {
  set v [catch {
    pager_rollback $::p1
  } msg]
  lappend v $msg
} {0 {}}
do_test pager2-2.29 {
  page_unref $::g1
  set ::g1 [page_get $::p1 1]
  page_read $::g1
} {Page-One}
do_test pager2-2.99 {
  page_unref $::g1
} {}

#do_test pager2-3.1 {
#  set v [catch {
#    set ::p1 [pager_open :memory: 15]
#  } msg]
#  if {$v} {lappend v $msg}
#  set v
#} {0}
do_test pager2-3.2 {
  pager_pagecount $::p1
} {1}
do_test pager2-3.3 {
  set v [catch {
    set ::g(1) [page_get $::p1 1]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager2-3.4 {
  page_read $::g(1)
} {Page-One}
do_test pager2-3.5 {
  for {set i 2} {$i<=20} {incr i} {
    set gx [page_get $::p1 $i]
    page_write $gx "Page-$i"
    page_unref $gx
  }
  pager_commit $::p1
  page_unref $::g(1)
} {}
for {set i 2} {$i<=20} {incr i} {
  set page1 [page_get $::p1 1]
  do_test pager2-3.6.[expr {$i-1}] [subst {
    set gx \[page_get $::p1 $i\]
    set v \[page_read \$gx\]
    page_unref \$gx
    set v
  }] "Page-$i"
  page_unref $page1
}
for {set i 1} {$i<=20} {incr i} {
  set page1 [page_get $::p1 1]
  regsub -all CNT {
    set ::g1 [page_get $::p1 CNT]
    set ::g2 [page_get $::p1 CNT]
    set ::vx [page_read $::g2]
    expr {$::g1==$::g2}
  } $i body;
  do_test pager2-3.7.$i.1 $body {1}
  regsub -all CNT {
    page_unref $::g2
    set vy [page_read $::g1]
    expr {$vy==$::vx}
  } $i body;
  do_test pager2-3.7.$i.2 $body {1}
  regsub -all CNT {
    page_unref $::g1
    set gx [page_get $::p1 CNT]
    set vy [page_read $gx]
    page_unref $gx
    expr {$vy==$::vx}
  } $i body;
  do_test pager2-3.7.$i.3 $body {1}
  page_unref $page1
}
do_test pager2-3.99 {
  pager_close $::p1
} {}

# tests of the checkpoint mechanism and api
#
do_test pager2-4.0 {
  set v [catch {
    set ::p1 [pager_open :memory: 15]
  } msg]
  if {$v} {lappend v $msg}
  set v
} {0}
do_test pager2-4.1 {
  set g1 [page_get $::p1 1]
  page_write $g1 "Page-1 v0"
  for {set i 2} {$i<=20} {incr i} {
    set gx [page_get $::p1 $i]
    page_write $gx "Page-$i v0"
    page_unref $gx
  }
  pager_commit $::p1
} {}
for {set i 1} {$i<=20} {incr i} {
  do_test pager2-4.2.$i {
    set gx [page_get $p1 $i]
    set v [page_read $gx]
    page_unref $gx
    set v
  } "Page-$i v0"
}
do_test pager2-4.3 {
  lrange [pager_stats $::p1] 0 1
} {ref 1}
do_test pager2-4.4 {
  lrange [pager_stats $::p1] 8 9
} {state 4}

for {set i 1} {$i<20} {incr i} {
  do_test pager2-4.5.$i.0 {
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v[expr {$i-1}]"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager2-4.5.$i.1 {
    page_write $g1 "Page-1 v$i"
    lrange [pager_stats $p1] 8 9
  } {state 4}
  do_test pager2-4.5.$i.2 {
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      page_write $gx "Page-$j v$i"
      page_unref $gx
      if {$j==$i} {
        pager_stmt_begin $p1
      }
    }
  } {}
  do_test pager2-4.5.$i.3 {
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v$i"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager2-4.5.$i.4 {
    pager_rollback $p1
    set res {}
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v[expr {$i-1}]"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager2-4.5.$i.5 {
    page_write $g1 "Page-1 v$i"
    lrange [pager_stats $p1] 8 9
  } {state 4}
  do_test pager2-4.5.$i.6 {
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      page_write $gx "Page-$j v$i"
      page_unref $gx
      if {$j==$i} {
        pager_stmt_begin $p1
      }
    }
  } {}
  do_test pager2-4.5.$i.7 {
    pager_stmt_rollback $p1
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      if {$j<=$i || $i==1} {
        set shouldbe "Page-$j v$i"
      } else {
        set shouldbe "Page-$j v[expr {$i-1}]"
      }
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager2-4.5.$i.8 {
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      page_write $gx "Page-$j v$i"
      page_unref $gx
      if {$j==$i} {
        pager_stmt_begin $p1
      }
    }
  } {}
  do_test pager2-4.5.$i.9 {
    pager_stmt_commit $p1
    for {set j 2} {$j<=20} {incr j} {
      set gx [page_get $p1 $j]
      set value [page_read $gx]
      page_unref $gx
      set shouldbe "Page-$j v$i"
      if {$value!=$shouldbe} {
        lappend res $value $shouldbe
      }
    }
    set res
  } {}
  do_test pager2-4.5.$i.10 {
    pager_commit $p1
    lrange [pager_stats $p1] 8 9
  } {state 4}
}

do_test pager2-4.99 {
  page_unref $::g1
  pager_close $::p1
} {}

} ;# ifcapable inmemory
} ;# end if( has pager_open command );


finish_test

# 2001 September 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 script is page cache subsystem.
#
# $Id: pager3.test,v 1.3 2005/03/29 03:11:00 danielk1977 Exp $


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

# This test makes sure the database file is truncated back to the correct
# length on a rollback.
#
# After some preliminary setup, a transaction is start at NOTE (1).
# The create table on the following line allocates an additional page
# at the end of the database file.  But that page is not written because
# the database still has a RESERVED lock, not an EXCLUSIVE lock.  The
# new page is held in memory and the size of the file is unchanged.
# The insert at NOTE (2) begins adding additional pages.  Then it hits
# a constraint error and aborts.  The abort causes sqlite3OsTruncate()
# to be called to restore the file to the same length as it was after
# the create table.  But the create table results had not yet been
# written so the file is actually lengthened by this truncate.  Finally,
# the rollback at NOTE (3) is called to undo all the changes since the
# begin.  This rollback should truncate the database again.
# 
# This test was added because the second truncate at NOTE (3) was not
# occurring on early versions of SQLite 3.0.
#
ifcapable tempdb {
  do_test pager3-1.1 {
    execsql {
      create table t1(a unique, b);
      insert into t1 values(1, 'abcdefghijklmnopqrstuvwxyz');
      insert into t1 values(2, 'abcdefghijklmnopqrstuvwxyz');
      update t1 set b=b||a||b;
      update t1 set b=b||a||b;
      update t1 set b=b||a||b;
      update t1 set b=b||a||b;
      update t1 set b=b||a||b;
      update t1 set b=b||a||b;
      create temp table t2 as select * from t1;
      begin;                  ------- NOTE (1)
      create table t3(x);
    }
    catchsql {
      insert into t1 select 4-a, b from t2;  ----- NOTE (2)
    }
    execsql {
      rollback;  ------- NOTE (3)
    }
    db close
    sqlite3 db test.db
    set r ok
    ifcapable {integrityck} {
      set r [execsql {
        pragma integrity_check;
      }]
    }
    set r
  } ok
}

finish_test