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Overview
| Comment: | Changes to wal.c so that SQLite can read even if the WAL file is opened read-only, provided the wal-index (shm file) is opened read/write. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 932d19da73c9673cdd4cc01289b17761 |
| User & Date: | dan 2010-07-15 18:20:54 |
Context
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2010-07-15
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| 18:32 | Optionally support shared-memory in /dev/shm or other tmpfs directory using an unsupported compile-time option. check-in: 534aab83 user: drh tags: trunk | |
| 18:20 | Changes to wal.c so that SQLite can read even if the WAL file is opened read-only, provided the wal-index (shm file) is opened read/write. check-in: 932d19da user: dan tags: trunk | |
| 17:54 | Handle the case where xShmMap returns SQLITE_BUSY. check-in: 75f53548 user: dan tags: trunk | |
Changes
Changes to src/wal.c.
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int nWiData; /* Size of array apWiData */ volatile u32 **apWiData; /* Pointer to wal-index content in memory */ u16 szPage; /* Database page size */ i16 readLock; /* Which read lock is being held. -1 for none */ u8 exclusiveMode; /* Non-zero if connection is in exclusive mode */ u8 writeLock; /* True if in a write transaction */ u8 ckptLock; /* True if holding a checkpoint lock */ WalIndexHdr hdr; /* Wal-index header for current transaction */ const 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 }; ................................................................................ pRet->readLock = -1; pRet->zWalName = zWalName; /* Open file handle on the write-ahead log file. */ flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL); rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags); if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){ rc = SQLITE_CANTOPEN; } if( rc!=SQLITE_OK ){ walIndexClose(pRet, 0); sqlite3OsClose(pRet->pWalFd); sqlite3_free(pRet); }else{ ................................................................................ */ int sqlite3WalBeginWriteTransaction(Wal *pWal){ int rc; /* Cannot start a write transaction without first holding a read ** transaction. */ assert( pWal->readLock>=0 ); /* Only one writer allowed at a time. Get the write lock. Return ** SQLITE_BUSY if unable. */ rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1); if( rc ){ return rc; |
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int nWiData; /* Size of array apWiData */ volatile u32 **apWiData; /* Pointer to wal-index content in memory */ u16 szPage; /* Database page size */ i16 readLock; /* Which read lock is being held. -1 for none */ u8 exclusiveMode; /* Non-zero if connection is in exclusive mode */ u8 writeLock; /* True if in a write transaction */ u8 ckptLock; /* True if holding a checkpoint lock */ u8 readOnly; /* True if the WAL file is open read-only */ WalIndexHdr hdr; /* Wal-index header for current transaction */ const 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 }; ................................................................................ pRet->readLock = -1; pRet->zWalName = zWalName; /* Open file handle on the write-ahead log file. */ flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL); rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags); if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){ pRet->readOnly = 1; } if( rc!=SQLITE_OK ){ walIndexClose(pRet, 0); sqlite3OsClose(pRet->pWalFd); sqlite3_free(pRet); }else{ ................................................................................ */ int sqlite3WalBeginWriteTransaction(Wal *pWal){ int rc; /* Cannot start a write transaction without first holding a read ** transaction. */ assert( pWal->readLock>=0 ); if( pWal->readOnly ){ return SQLITE_READONLY; } /* Only one writer allowed at a time. Get the write lock. Return ** SQLITE_BUSY if unable. */ rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1); if( rc ){ return rc; |
Changes to test/wal2.test.
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 |
do_test wal2-13.1.1 {
list [file exists test.db-shm] [file exists test.db-wal]
} {1 1}
faultsim_save_and_close
foreach {tn db_perm wal_perm shm_perm can_open can_read can_write} {
2 00644 00644 00644 1 1 1
3 00644 00400 00644 1 0 0
4 00644 00644 00400 1 0 0
5 00400 00644 00644 1 1 0
7 00644 00000 00644 1 0 0
8 00644 00644 00000 1 0 0
9 00000 00644 00644 0 0 0
} {
|
| |
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 |
do_test wal2-13.1.1 {
list [file exists test.db-shm] [file exists test.db-wal]
} {1 1}
faultsim_save_and_close
foreach {tn db_perm wal_perm shm_perm can_open can_read can_write} {
2 00644 00644 00644 1 1 1
3 00644 00400 00644 1 1 0
4 00644 00644 00400 1 0 0
5 00400 00644 00644 1 1 0
7 00644 00000 00644 1 0 0
8 00644 00644 00000 1 0 0
9 00000 00644 00644 0 0 0
} {
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