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Overview
Comment: | Avoid locking shm-lock WAL_READ_LOCK(0) during recovery. Doing this allows recovery to proceed while a readonly_shm connection in unlocked mode has an ongoing read transaction. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | readonly-wal-recovery |
Files: | files | file ages | folders |
SHA3-256: |
5190d84a296b7cf716ef43bf7b6d4d35 |
User & Date: | dan 2017-11-02 11:12:03.045 |
Context
2017-11-02
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18:57 | Fix test cases in wal2.test broken by the locking change in the previous commit. (check-in: f569c35172 user: dan tags: readonly-wal-recovery) | |
11:12 | Avoid locking shm-lock WAL_READ_LOCK(0) during recovery. Doing this allows recovery to proceed while a readonly_shm connection in unlocked mode has an ongoing read transaction. (check-in: 5190d84a29 user: dan tags: readonly-wal-recovery) | |
2017-11-01
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20:59 | If a readonly_shm connection cannot map the *-shm file because no other process is holding the DMS lock, have it read from the database file only, ignoring any content in the wal file. (check-in: ce5d13c2de user: dan tags: readonly-wal-recovery) | |
Changes
Changes to src/wal.c.
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1097 1098 1099 1100 1101 1102 1103 | ** the necessary locks, this routine returns SQLITE_BUSY. */ static int walIndexRecover(Wal *pWal){ int rc; /* Return Code */ i64 nSize; /* Size of log file */ u32 aFrameCksum[2] = {0, 0}; int iLock; /* Lock offset to lock for checkpoint */ | < > | | > > > > > | 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 | ** the necessary locks, this routine returns SQLITE_BUSY. */ static int walIndexRecover(Wal *pWal){ int rc; /* Return Code */ i64 nSize; /* Size of log file */ u32 aFrameCksum[2] = {0, 0}; int iLock; /* Lock offset to lock for checkpoint */ /* Obtain an exclusive lock on all byte in the locking range not already ** locked by the caller. The caller is guaranteed to have locked the ** WAL_WRITE_LOCK byte, and may have also locked the WAL_CKPT_LOCK byte. ** If successful, the same bytes that are locked here are unlocked before ** this function returns. */ assert( pWal->ckptLock==1 || pWal->ckptLock==0 ); assert( WAL_ALL_BUT_WRITE==WAL_WRITE_LOCK+1 ); assert( WAL_CKPT_LOCK==WAL_ALL_BUT_WRITE ); assert( pWal->writeLock ); iLock = WAL_ALL_BUT_WRITE + pWal->ckptLock; rc = walLockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock); if( rc==SQLITE_OK ){ rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1); if( rc!=SQLITE_OK ){ walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock); } } if( rc ){ return rc; } WALTRACE(("WAL%p: recovery begin...\n", pWal)); memset(&pWal->hdr, 0, sizeof(WalIndexHdr)); rc = sqlite3OsFileSize(pWal->pWalFd, &nSize); if( rc!=SQLITE_OK ){ goto recovery_error; |
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1252 1253 1254 1255 1256 1257 1258 | pWal->hdr.mxFrame, pWal->zWalName ); } } recovery_error: WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok")); | | > | 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 | pWal->hdr.mxFrame, pWal->zWalName ); } } recovery_error: WALTRACE(("WAL%p: recovery %s\n", pWal, rc ? "failed" : "ok")); walUnlockExclusive(pWal, iLock, WAL_READ_LOCK(0)-iLock); walUnlockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1); return rc; } /* ** Close an open wal-index. */ static void walIndexClose(Wal *pWal, int isDelete){ |
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Changes to test/walro2.test.
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77 78 79 80 81 82 83 84 85 86 87 | code3 { sqlite3 db3 test.db2 } sql3 { SELECT * FROM t1 } } {a b c d} do_test 1.3.2 { sql1 { SELECT * FROM t1 } } {a b c d} } finish_test | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 | code3 { sqlite3 db3 test.db2 } sql3 { SELECT * FROM t1 } } {a b c d} do_test 1.3.2 { sql1 { SELECT * FROM t1 } } {a b c d} code1 { db close } code2 { db2 close } code3 { db3 close } do_test 2.1 { code2 { sqlite3 db2 test.db } sql2 { INSERT INTO t1 VALUES('e', 'f'); INSERT INTO t1 VALUES('g', 'h'); } file exists test.db-shm } {1} do_test 2.2 { forcecopy test.db test.db2 forcecopy test.db-wal test.db2-wal forcecopy test.db-shm test.db2-shm code1 { sqlite3 db file:test.db2?readonly_shm=1 } sql1 { BEGIN; SELECT * FROM t1; } } {a b c d} do_test 2.3.1 { code3 { sqlite3 db3 test.db2 } sql3 { SELECT * FROM t1 } } {a b c d e f g h} } finish_test |