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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. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
37de3eab67f12ae1ce5bc8d5e541c64f |
User & Date: | dan 2016-05-24 16:20:51.379 |
Context
2016-05-24
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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
Changes to src/test6.c.
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211 212 213 214 215 216 217 | 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 | > | > | 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, |
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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. */ |
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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.
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3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 | ** 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++; } | > > > > > | | 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. |
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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 |