From: drh Date: Wed, 2 Jun 2010 14:45:51 +0000 (+0000) Subject: Changes to make WAL more robust against SHM locking failures and OOM errors. X-Git-Tag: version-3.7.2~320 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aab4c02e4763fd537dafd9dca3f414a125977cd0;p=thirdparty%2Fsqlite.git Changes to make WAL more robust against SHM locking failures and OOM errors. FossilOrigin-Name: ebf4041383c3cdddb5861960359abd209d4a1028 --- diff --git a/manifest b/manifest index 7791d33a96..748756246d 100644 --- a/manifest +++ b/manifest @@ -1,8 +1,8 @@ -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 -C In\sthe\srowhash.test,\smake\ssure\sglobal\svariables\sare\scleared\sprior\sto\suse. -D 2010-06-02T14:43:30 +C Changes\sto\smake\sWAL\smore\srobust\sagainst\sSHM\slocking\sfailures\sand\sOOM\serrors. +D 2010-06-02T14:45:51 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0 F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654 @@ -155,7 +155,7 @@ F src/os.c 1516984144e26734f97748f891f1a04f9e294c2e F src/os.h 6f604986f0ef0ca288c2330b16051ff70b431e8c F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f F src/os_os2.c 665876d5eec7585226b0a1cf5e18098de2b2da19 -F src/os_unix.c 31511480da88947d39c9e12560a11d4495e19832 +F src/os_unix.c 7ae9257f65b32f20d777e880700a84e7dac8051e F src/os_win.c f815403c51a2adad30244374c801dd7fd2734567 F src/pager.c acbef227bf158776449907c275c5d9332e4e52f9 F src/pager.h 76466c3a5af56943537f68b1f16567101a0cd1d0 @@ -171,7 +171,7 @@ F src/resolve.c ac5f1a713cd1ae77f08b83cc69581e11bf5ae6f9 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697 F src/select.c c03d8a0565febcde8c6a12c5d77d065fddae889b F src/shell.c fd4ccdb37c3b68de0623eb938a649e0990710714 -F src/sqlite.h.in 4f72e39f1edeccaf2a5913483bce2f704492b892 +F src/sqlite.h.in 60f4fcfe18bcb53ed0002989837b68aeeba79a5e F src/sqlite3ext.h 69dfb8116af51b84a029cddb3b35062354270c89 F src/sqliteInt.h 4e26920ede6da1b6f154251fb4f89f65f78979e0 F src/sqliteLimit.h 196e2f83c3b444c4548fc1874f52f84fdbda40f3 @@ -227,7 +227,7 @@ F src/vdbeblob.c 5327132a42a91e8b7acfb60b9d2c3b1c5c863e0e F src/vdbemem.c 2a82f455f6ca6f78b59fb312f96054c04ae0ead1 F src/vdbetrace.c 864cef96919323482ebd9986f2132435115e9cc2 F src/vtab.c a0f8a40274e4261696ef57aa806de2776ab72cda -F src/wal.c 2bd4ef3bfeb2481e9edd3d1858ff8db0bc3a650d +F src/wal.c e36af9e75768d1dc790392089b10cf272abccefa F src/wal.h 1c1c9feb629b7f4afcbe0b47f80f47c5551d3a02 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f F src/where.c 75fee9e255b62f773fcadd1d1f25b6f63ac7a356 @@ -818,14 +818,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f -P c24ac3563f46fc6bcf7e45ee171afd3ae7d2faa8 -R 00a157c07ad0e7a71db4a2e73d42f8e4 +P 28efe0a40405567f3eaf334b6603282d5adac792 +R 9d892b2c2c5007a01a863a8338bf83dd U drh -Z e46aac16978246262ba376cf49913464 +Z 8d64b4080a97b8f66f1bf92b76c05ca5 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) -iD8DBQFMBm4VoxKgR168RlERAhb3AJ9bqFhxwgZ6DohhkaiSxdI+Dne3iQCfS41x -jKYaDVEfVJDuwV1vKuW32gg= -=jOCy +iD8DBQFMBm6ioxKgR168RlERAqErAJ9ySZWhR4zIr4TMIPtUXND7LUScBACeK1dS +Xn9N4779qMX9jCkGApiXX1s= +=nr7w -----END PGP SIGNATURE----- diff --git a/manifest.uuid b/manifest.uuid index 8b9b8236f9..2f899a0513 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -28efe0a40405567f3eaf334b6603282d5adac792 \ No newline at end of file +ebf4041383c3cdddb5861960359abd209d4a1028 \ No newline at end of file diff --git a/src/os_unix.c b/src/os_unix.c index 9d4a780a61..95f20bad9f 100644 --- a/src/os_unix.c +++ b/src/os_unix.c @@ -3362,7 +3362,7 @@ static int unixShmOpen( rc = SQLITE_OK; if( unixShmSystemLock(pShmNode, F_WRLCK, UNIX_SHM_DMS, 1)==SQLITE_OK ){ if( ftruncate(pShmNode->h, 0) ){ - rc = SQLITE_IOERR; + rc = SQLITE_IOERR_SHMOPEN; } } if( rc==SQLITE_OK ){ @@ -3469,7 +3469,7 @@ static int unixShmSize( if( reqSize<=(int)sStat.st_size ) break; }else{ *pNewSize = 0; - rc = SQLITE_IOERR; + rc = SQLITE_IOERR_SHMSIZE; break; } rc = ftruncate(pShmNode->h, reqSize); diff --git a/src/sqlite.h.in b/src/sqlite.h.in index e6a1659b94..952f389544 100644 --- a/src/sqlite.h.in +++ b/src/sqlite.h.in @@ -388,7 +388,7 @@ int sqlite3_exec( #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ #define SQLITE_FULL 13 /* Insertion failed because database is full */ #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ -#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ +#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ #define SQLITE_EMPTY 16 /* Database is empty */ #define SQLITE_SCHEMA 17 /* The database schema changed */ #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ @@ -444,6 +444,9 @@ int sqlite3_exec( #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) +#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) +#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) +#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) diff --git a/src/wal.c b/src/wal.c index dc143b4b17..397a592b5d 100644 --- a/src/wal.c +++ b/src/wal.c @@ -377,6 +377,9 @@ struct Wal { WalIndexHdr hdr; /* Wal-index header for current transaction */ char *zWalName; /* Name of WAL file */ u32 nCkpt; /* Checkpoint sequence counter in the wal-header */ +#ifdef SQLITE_DEBUG + u8 lockError; /* True if a locking error has occurred */ +#endif }; /* @@ -629,6 +632,7 @@ static int walLockShared(Wal *pWal, int lockIdx){ SQLITE_SHM_LOCK | SQLITE_SHM_SHARED); WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal, walLockName(lockIdx), rc ? "failed" : "ok")); + VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); ) return rc; } static void walUnlockShared(Wal *pWal, int lockIdx){ @@ -644,6 +648,7 @@ static int walLockExclusive(Wal *pWal, int lockIdx, int n){ SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE); WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal, walLockName(lockIdx), n, rc ? "failed" : "ok")); + VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); ) return rc; } static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){ @@ -1693,7 +1698,7 @@ static int walIndexReadHdr(Wal *pWal, int *pChanged){ ** so it takes care to hold an exclusive lock on the corresponding ** WAL_READ_LOCK() while changing values. */ -static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal){ +static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){ volatile WalIndexHdr *pHdr; /* Header of the wal-index */ volatile WalCkptInfo *pInfo; /* Checkpoint information in wal-index */ u32 mxReadMark; /* Largest aReadMark[] value */ @@ -1703,6 +1708,12 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal){ assert( pWal->readLock<0 ); /* Not currently locked */ + /* Take steps to avoid spinning forever if there is a protocol error. */ + if( cnt>5 ){ + if( cnt>100 ) return SQLITE_PROTOCOL; + sqlite3OsSleep(pWal->pVfs, 1); + } + if( !useWal ){ rc = walIndexReadHdr(pWal, pChanged); if( rc==SQLITE_BUSY ){ @@ -1820,9 +1831,10 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal){ */ int sqlite3WalBeginReadTransaction(Wal *pWal, int *pChanged){ int rc; /* Return code */ + int cnt = 0; /* Number of TryBeginRead attempts */ do{ - rc = walTryBeginRead(pWal, pChanged, 0); + rc = walTryBeginRead(pWal, pChanged, 0, ++cnt); }while( rc==WAL_RETRY ); walIndexUnmap(pWal); return rc; @@ -1859,8 +1871,8 @@ int sqlite3WalRead( u32 iLast = pWal->hdr.mxFrame; /* Last page in WAL for this reader */ int iHash; /* Used to loop through N hash tables */ - /* This routine is only called from within a read transaction */ - assert( pWal->readLock>=0 ); + /* This routine is only be called from within a read transaction. */ + assert( pWal->readLock>=0 || pWal->lockError ); /* If the "last page" field of the wal-index header snapshot is 0, then ** no data will be read from the wal under any circumstances. Return early @@ -1982,7 +1994,7 @@ int sqlite3WalRead( ** Set *pPgno to the size of the database file (or zero, if unknown). */ void sqlite3WalDbsize(Wal *pWal, Pgno *pPgno){ - assert( pWal->readLock>=0 ); + assert( pWal->readLock>=0 || pWal->lockError ); *pPgno = pWal->hdr.nPage; } @@ -2133,6 +2145,8 @@ int sqlite3WalSavepointUndo(Wal *pWal, u32 *aWalData){ */ static int walRestartLog(Wal *pWal){ int rc = SQLITE_OK; + int cnt; + if( pWal->readLock==0 && SQLITE_OK==(rc = walIndexMap(pWal, walMappingSize(pWal->hdr.mxFrame))) ){ @@ -2163,9 +2177,10 @@ static int walRestartLog(Wal *pWal){ } walUnlockShared(pWal, WAL_READ_LOCK(0)); pWal->readLock = -1; + cnt = 0; do{ int notUsed; - rc = walTryBeginRead(pWal, ¬Used, 1); + rc = walTryBeginRead(pWal, ¬Used, 1, ++cnt); }while( rc==WAL_RETRY ); /* Unmap the wal-index before returning. Otherwise the VFS layer may @@ -2418,22 +2433,25 @@ int sqlite3WalCallback(Wal *pWal){ */ int sqlite3WalExclusiveMode(Wal *pWal, int op){ int rc; - assert( pWal->writeLock==0 && pWal->readLock>=0 ); + assert( pWal->writeLock==0 ); + /* pWal->readLock is usually set, but might be -1 if there was a prior OOM */ + assert( pWal->readLock>=0 || pWal->lockError ); if( op==0 ){ if( pWal->exclusiveMode ){ pWal->exclusiveMode = 0; - if( walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK ){ + if( pWal->readLock>=0 + && walLockShared(pWal, WAL_READ_LOCK(pWal->readLock))!=SQLITE_OK + ){ pWal->exclusiveMode = 1; } rc = pWal->exclusiveMode==0; }else{ - /* No changes. Either already in locking_mode=NORMAL or else the - ** acquisition of the read-lock failed. The pager must continue to - ** hold the database exclusive lock. */ + /* Already in locking_mode=NORMAL */ rc = 0; } }else if( op>0 ){ assert( pWal->exclusiveMode==0 ); + assert( pWal->readLock>=0 ); walUnlockShared(pWal, WAL_READ_LOCK(pWal->readLock)); pWal->exclusiveMode = 1; rc = 1;