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Overview
| Comment: | Passive checkpoints do not use the busy-handler. So, in order to minimize visible changes for legacy applications, do not enable blocking locks for passive checkpoints. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | wal-setlk-changes |
| Files: | files | file ages | folders |
| SHA3-256: |
9c2b4bdd03716bf492ba85198717f308 |
| User & Date: | dan 2020-06-29 19:58:26 |
Context
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2020-06-29
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| 19:58 | Passive checkpoints do not use the busy-handler. So, in order to minimize visible changes for legacy applications, do not enable blocking locks for passive checkpoints. (Leaf check-in: 9c2b4bdd03 user: dan tags: wal-setlk-changes) | |
| 18:22 | Change things so that if SQLITE_ENABLE_SETLK_TIMEOUT is defined as 2 instead of 1, all blocking locks are taken for a single millisecond and the default busy-handler invoked as normal. (check-in: ac381e6eb3 user: dan tags: wal-setlk-changes) | |
Changes
Changes to src/wal.c.
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/* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
** in the SQLITE_CHECKPOINT_PASSIVE mode. */
assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
if( pWal->readOnly ) return SQLITE_READONLY;
WALTRACE(("WAL%p: checkpoint begins\n", pWal));
/* Enable blocking locks, if possible. If blocking locks are successfully
** enabled, set xBusy2=0 so that the busy-handler is never invoked. */
sqlite3WalDb(pWal, db);
(void)walEnableBlocking(pWal);
/* IMPLEMENTATION-OF: R-62028-47212 All calls obtain an exclusive
** "checkpoint" lock on the database file.
** EVIDENCE-OF: R-10421-19736 If any other process is running a
** checkpoint operation at the same time, the lock cannot be obtained and
** SQLITE_BUSY is returned.
** EVIDENCE-OF: R-53820-33897 Even if there is a busy-handler configured,
................................................................................
}
/* Read the wal-index header. */
if( rc==SQLITE_OK ){
walDisableBlocking(pWal);
rc = walIndexReadHdr(pWal, &isChanged);
(void)walEnableBlocking(pWal);
if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
}
}
/* Copy data from the log to the database file. */
if( rc==SQLITE_OK ){
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/* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
** in the SQLITE_CHECKPOINT_PASSIVE mode. */
assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );
if( pWal->readOnly ) return SQLITE_READONLY;
WALTRACE(("WAL%p: checkpoint begins\n", pWal));
/* Enable blocking locks, if possible. */
sqlite3WalDb(pWal, db);
if( xBusy2 ) (void)walEnableBlocking(pWal);
/* IMPLEMENTATION-OF: R-62028-47212 All calls obtain an exclusive
** "checkpoint" lock on the database file.
** EVIDENCE-OF: R-10421-19736 If any other process is running a
** checkpoint operation at the same time, the lock cannot be obtained and
** SQLITE_BUSY is returned.
** EVIDENCE-OF: R-53820-33897 Even if there is a busy-handler configured,
................................................................................
}
/* Read the wal-index header. */
if( rc==SQLITE_OK ){
walDisableBlocking(pWal);
rc = walIndexReadHdr(pWal, &isChanged);
if( xBusy2 ) (void)walEnableBlocking(pWal);
if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
}
}
/* Copy data from the log to the database file. */
if( rc==SQLITE_OK ){
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