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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. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
932d19da73c9673cdd4cc01289b17761 |
| User & Date: | dan 2010-07-15 18:20:54.000 |
Context
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2010-07-15
| ||
| 18:32 | Optionally support shared-memory in /dev/shm or other tmpfs directory using an unsupported compile-time option. (check-in: 534aab837e 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: 932d19da73 user: dan tags: trunk) | |
| 17:54 | Handle the case where xShmMap returns SQLITE_BUSY. (check-in: 75f5354876 user: dan tags: trunk) | |
Changes
Changes to src/wal.c.
| ︙ | ︙ | |||
411 412 413 414 415 416 417 418 419 420 421 422 423 424 | 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 }; | > | 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 | 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 }; |
| ︙ | ︙ | |||
1223 1224 1225 1226 1227 1228 1229 |
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 ){
| | | 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 |
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{
|
| ︙ | ︙ | |||
2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 |
*/
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;
| > > > > | 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 |
*/
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 |
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
| | | 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
} {
|
| ︙ | ︙ |