SQLite

** 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 1.518 2008/12/19 16:31:11 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/

  Pgno pgno;                    /* The page number of a page in journal */
  u32 cksum;                    /* Checksum used for sanity checking */
  u8 *aData = (u8 *)pPager->pTmpSpace;   /* Temp storage for a page */
  sqlite3_file *jfd = (isMainJrnl ? pPager->jfd : pPager->sjfd);

  /* The temp storage must be allocated at this point */
  assert( aData );
  assert( isMainJrnl || pDone );

  rc = read32bits(jfd, offset, &pgno);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3OsRead(jfd, aData, pPager->pageSize, offset+4);
  if( rc!=SQLITE_OK ) return rc;
  pPager->journalOff += pPager->pageSize + 4;

    */
    void *pData;
    pData = pPg->pData;
    memcpy(pData, aData, pPager->pageSize);
    if( pPager->xReiniter ){
      pPager->xReiniter(pPg);
    }
    if( isMainJrnl && (!pDone || pPager->journalOff<=pPager->journalHdr) ){
      /* If the contents of this page were just restored from the main 
      ** journal file, then its content must be as they were when the 
      ** transaction was first opened. In this case we can mark the page
      ** as clean, since there will be no need to write it out to the.
      **
      ** There is one exception to this rule. If the page is being rolled
      ** back as part of a savepoint (or statement) rollback from an 
      ** unsynced portion of the main journal file, then it is not safe
      ** to mark the page as clean. This is because marking the page as
      ** clean will clear the PGHDR_NEED_SYNC flag. Since the page is
      ** already in the journal file (recorded in Pager.pInJournal) and
      ** the PGHDR_NEED_SYNC flag is cleared, if the page is written to
      ** again within this transaction, it will be marked as dirty but
      ** the PGHDR_NEED_SYNC flag will not be set. It could then potentially
      ** be written out into the database file before its journal file
      ** segment is synced. If a crash occurs during or following this,
      ** database corruption may ensue.
      */
      sqlite3PcacheMakeClean(pPg);
    }
#ifdef SQLITE_CHECK_PAGES
    pPg->pageHash = pager_pagehash(pPg);
#endif
    /* If this was page 1, then restore the value of Pager.dbFileVers.
    ** Do this before any decoding. */

#
#    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 runs all tests.
#
# $Id: quick.test,v 1.90 2008/12/19 16:31:12 danielk1977 Exp $

proc lshift {lvar} {
  upvar $lvar l
  set ret [lindex $l 0]
  set l [lrange $l 1 end]
  return $ret
}

  memleak.test
  misc7.test
  misuse.test
  mutex2.test
  onefile.test
  permutations.test
  quick.test
  savepoint4.test
  select9.test
  soak.test
  speed1.test
  speed1p.test
  speed2.test
  speed3.test
  speed4.test

# 2008 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.
#
#***********************************************************************
#
# $Id: savepoint4.test,v 1.1 2008/12/19 16:31:12 danielk1977 Exp $

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


proc signature {} {
  return [db eval {SELECT count(*), md5sum(x) FROM t3}]
}

expr srand(0)

do_test savepoint4-1 {
  execsql {
    PRAGMA cache_size=10;
    BEGIN;
    CREATE TABLE t3(x TEXT);
    INSERT INTO t3 VALUES(randstr(10,400));
    INSERT INTO t3 VALUES(randstr(10,400));
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    COMMIT;
    SELECT count(*) FROM t3;
  }
} {1024}


unset -nocomplain ::sig

for {set ii 1} {$ii<25} {incr ii} {
  set ::sig [signature]

  set crashed 1
  for {set iDelay 1} {$crashed} {incr iDelay} {
    do_test savepoint4-$ii.1.$iDelay {
      set ret [crashsql -delay $iDelay -file test.db-journal {
        PRAGMA cache_size = 20;
        SAVEPOINT one;
          DELETE FROM t3 WHERE random()%2==0;
          SAVEPOINT two;
            INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
           ROLLBACK TO two;
            UPDATE t3 SET x = randstr(10, 400) WHERE random()%10;
          RELEASE two;
        ROLLBACK TO one;
      }]
      signature
    } $::sig
    set crashed [lindex $ret 0]
    integrity_check savepoint4-$ii.1.$iDelay.integrity
  }

  do_test savepoint4-$ii.2 {
    execsql {
      DELETE FROM t3 WHERE random()%10==0;
      INSERT INTO t3 SELECT randstr(10,10)||x FROM t3 WHERE random()%9==0;
    }
  } {}
}

finish_test