SQLite

Check-in [37de3eab67]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Fix an obscure problem with transactions written in "PRAGMA synchronous=full" mode on systems that do not support POWERSAFE_OVERWRITE causing an xSync() call to be omitted if the last frame written by a transaction is aligned to a sector boundary. This means that if a power failure or OS crash occurs very soon after such a transaction is committed, it may be lost following system recovery.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 37de3eab67f12ae1ce5bc8d5e541c64fc6b1fd80
User & Date: dan 2016-05-24 16:20:51.379
Context
2016-05-24
18:50
Minor change to the walcrash4.test module so that it works when SQLITE_DEFAULT_WAL_SYNCHRONOUS is set to something other than 2. (check-in: 61e239bc43 user: drh tags: trunk)
16:20
Fix an obscure problem with transactions written in "PRAGMA synchronous=full" mode on systems that do not support POWERSAFE_OVERWRITE causing an xSync() call to be omitted if the last frame written by a transaction is aligned to a sector boundary. This means that if a power failure or OS crash occurs very soon after such a transaction is committed, it may be lost following system recovery. (check-in: 37de3eab67 user: dan tags: trunk)
00:40
Improvements to the initialization of the push-down automoton for the Lemon-generated parser. Smaller and faster. (check-in: 3b28b68e23 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/test6.c.
211
212
213
214
215
216
217

218

219
220
221
222
223
224
225
    sqlite3_randomness(sizeof(int), &iFinal);
    iFinal = ((iFinal<0)?-1*iFinal:iFinal)%nWrite;
    for(pWrite=g.pWriteList; iFinal>0; pWrite=pWrite->pNext) iFinal--;
    pFinal = pWrite;
  }

#ifdef TRACE_CRASHTEST

  printf("Sync %s (is %s crash)\n", pFile->zName, (isCrash?"a":"not a"));

#endif

  ppPtr = &g.pWriteList;
  for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){
    sqlite3_file *pRealFile = pWrite->pFile->pRealFile;

    /* (eAction==1)      -> write block out normally,







>
|
>







211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
    sqlite3_randomness(sizeof(int), &iFinal);
    iFinal = ((iFinal<0)?-1*iFinal:iFinal)%nWrite;
    for(pWrite=g.pWriteList; iFinal>0; pWrite=pWrite->pNext) iFinal--;
    pFinal = pWrite;
  }

#ifdef TRACE_CRASHTEST
  if( pFile ){
    printf("Sync %s (is %s crash)\n", pFile->zName, (isCrash?"a":"not a"));
  }
#endif

  ppPtr = &g.pWriteList;
  for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){
    sqlite3_file *pRealFile = pWrite->pFile->pRealFile;

    /* (eAction==1)      -> write block out normally,
794
795
796
797
798
799
800





















801
802
803
804
805
806
807
  }
  if( setSectorsize ){
    *piSectorSize = iSectorSize;
  }

  return TCL_OK;
}






















/*
** tclcmd:   sqlite_crash_enable ENABLE
**
** Parameter ENABLE must be a boolean value. If true, then the "crash"
** vfs is added to the system. If false, it is removed.
*/







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







796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
  }
  if( setSectorsize ){
    *piSectorSize = iSectorSize;
  }

  return TCL_OK;
}

/*
** tclcmd:   sqlite3_crash_now
**
** Simulate a crash immediately. This function does not return 
** (writeListSync() calls exit(-1)).
*/
static int crashNowCmd(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  if( objc!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, "");
    return TCL_ERROR;
  }
  writeListSync(0, 1);
  assert( 0 );
  return TCL_OK;
}

/*
** tclcmd:   sqlite_crash_enable ENABLE
**
** Parameter ENABLE must be a boolean value. If true, then the "crash"
** vfs is added to the system. If false, it is removed.
*/
1030
1031
1032
1033
1034
1035
1036

1037
1038
1039
1040
1041
1042
1043
1044
1045
/*
** This procedure registers the TCL procedures defined in this file.
*/
int Sqlitetest6_Init(Tcl_Interp *interp){
#ifndef SQLITE_OMIT_DISKIO
  Tcl_CreateObjCommand(interp, "sqlite3_crash_enable", crashEnableCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);

  Tcl_CreateObjCommand(interp, "sqlite3_simulate_device", devSymObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "unregister_devsim", dsUnregisterObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "register_jt_vfs", jtObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "unregister_jt_vfs", jtUnregisterObjCmd, 0, 0);
#endif
  return TCL_OK;
}

#endif /* SQLITE_TEST */







>









1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
/*
** This procedure registers the TCL procedures defined in this file.
*/
int Sqlitetest6_Init(Tcl_Interp *interp){
#ifndef SQLITE_OMIT_DISKIO
  Tcl_CreateObjCommand(interp, "sqlite3_crash_enable", crashEnableCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "sqlite3_crash_now", crashNowCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "sqlite3_simulate_device", devSymObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "unregister_devsim", dsUnregisterObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "register_jt_vfs", jtObjCmd, 0, 0);
  Tcl_CreateObjCommand(interp, "unregister_jt_vfs", jtUnregisterObjCmd, 0, 0);
#endif
  return TCL_OK;
}

#endif /* SQLITE_TEST */
Changes to src/wal.c.
3105
3106
3107
3108
3109
3110
3111

3112
3113
3114


3115
3116
3117
3118
3119
3120


3121
3122
3123
3124
3125
3126
3127
3128
  ** needed and only the sync is done.  If padding is needed, then the
  ** final frame is repeated (with its commit mark) until the next sector
  ** 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 && (sync_flags & WAL_SYNC_TRANSACTIONS)!=0 ){

    if( pWal->padToSectorBoundary ){
      int sectorSize = sqlite3SectorSize(pWal->pWalFd);
      w.iSyncPoint = ((iOffset+sectorSize-1)/sectorSize)*sectorSize;


      while( iOffset<w.iSyncPoint ){
        rc = walWriteOneFrame(&w, pLast, nTruncate, iOffset);
        if( rc ) return rc;
        iOffset += szFrame;
        nExtra++;
      }


    }else{
      rc = sqlite3OsSync(w.pFd, sync_flags & SQLITE_SYNC_MASK);
    }
  }

  /* If this frame set completes the first transaction in the WAL and
  ** if PRAGMA journal_size_limit is set, then truncate the WAL to the
  ** journal size limit, if possible.







>



>
>






>
>
|







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
  ** needed and only the sync is done.  If padding is needed, then the
  ** final frame is repeated (with its commit mark) until the next sector
  ** 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 && (sync_flags & WAL_SYNC_TRANSACTIONS)!=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;
        nExtra++;
      }
    }
    if( bSync ){
      assert( rc==SQLITE_OK );
      rc = sqlite3OsSync(w.pFd, sync_flags & SQLITE_SYNC_MASK);
    }
  }

  /* If this frame set completes the first transaction in the WAL and
  ** if PRAGMA journal_size_limit is set, then truncate the WAL to the
  ** journal size limit, if possible.
Added test/walcrash4.test.






















































































































































>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
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
68
69
70
71
72
73
74
75
# 2010 May 25
#
# 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.
#
#***********************************************************************
#


set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/wal_common.tcl
ifcapable !wal {finish_test ; return }
set testprefix walcrash4

#-------------------------------------------------------------------------
# At one point, if "PRAGMA synchronous=full" is set and the platform
# does not support POWERSAFE_OVERWRITE, and the last frame written to 
# the wal file in a transaction is aligned with a sector boundary, the
# xSync() call was omitted. 
#
# The following test verifies that this has been fixed.
#
do_execsql_test 1.0 {
  PRAGMA autovacuum = 0;
  PRAGMA page_size = 1024;
  PRAGMA journal_mode = wal;
  PRAGMA main.synchronous = full;
} {wal}

faultsim_save_and_close

for {set nExtra 0} {$nExtra < 10} {incr nExtra} {
  for {set i 0} {$i < 10} {incr i} {
    do_test 1.nExtra=$nExtra.i=$i.1 {
      faultsim_restore_and_reopen
    
      set fd [open crash.tcl w]
      puts $fd [subst -nocommands {
        sqlite3_crash_enable 1
        sqlite3_test_control_pending_byte $::sqlite_pending_byte
        sqlite3 db test.db -vfs crash
        db eval {
          BEGIN;
          CREATE TABLE t1(x UNIQUE);
        }
        for {set e 2} {[set e] < ($nExtra+2)} {incr e} {
          db eval "CREATE TABLE t[set e] (x)"
        }
        db eval {
          INSERT INTO t1 VALUES( randomblob(170000) );
          COMMIT;
        }
        sqlite3_crash_now
      }]
      close $fd
    
      set r [catch { exec [info nameofexec] crash.tcl >@stdout } msg]
      list $r $msg
    } {1 {child process exited abnormally}}
  
    do_execsql_test 1.nExtra=$nExtra.i=$i.2 { 
      SELECT count(*) FROM t1;
      PRAGMA integrity_check;
    } {1 ok}
  } 
}


finish_test