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Further tests and changes related to switching between WAL and rollback modes.

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FossilOrigin-Name: 1236318477787a612f02cc98caf2931bd2e99d94
This commit is contained in:
dan
2010-04-22 06:27:04 +00:00
parent b978002743
commit ede6eb8d1d
6 changed files with 92 additions and 27 deletions
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36
src/pager.c
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@@ -3732,18 +3732,13 @@ static int hasHotJournal(Pager *pPager, int *pExists){
** an SQLite error code.
**
** The caller must hold a SHARED lock on the database file to call this
** function.
** function. Because an EXCLUSIVE lock on the db file is required to delete
** a WAL, this ensures there is no race condition between the xAccess()
** below and an xDelete() being executed by some other connection.
*/
static int pagerHasWAL(Pager *pPager, int *pExists){
int rc; /* Return code */
/* Check that a SHARED lock is held on the database file. Because an
** EXCLUSIVE lock on the db file is required to delete a WAL, this
** ensures there is no race condition between the xAccess() below and
** an xDelete() being executed by some other connection.
*/
assert( pPager->state>=PAGER_SHARED );
if( !pPager->tempFile ){
char *zLog = sqlite3_mprintf("%s-wal", pPager->zFilename);
if( !zLog ){
@@ -5755,12 +5750,29 @@ int sqlite3PagerOpenLog(Pager *pPager, int *pisOpen){
*/
int sqlite3PagerCloseLog(Pager *pPager){
int rc = SQLITE_OK;
if( pPager->pLog ){
/* Try to obtain an EXCLUSIVE lock on the database file. */
assert( pPager->journalMode==PAGER_JOURNALMODE_WAL );
/* If the log file is not already open, but does exist in the file-system,
** it may need to be checkpointed before the connection can switch to
** rollback mode. Open it now so this can happen.
*/
if( !pPager->pLog ){
int logexists = 0;
rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
if( rc==SQLITE_OK ){
rc = pagerHasWAL(pPager, &logexists);
}
if( rc==SQLITE_OK && logexists ){
rc = sqlite3LogOpen(pPager->pVfs, pPager->zFilename, &pPager->pLog);
}
}
/* Checkpoint and close the log. Because an EXCLUSIVE lock is held on
** the database file, the log and log-summary files will be deleted.
*/
if( rc==SQLITE_OK && pPager->pLog ){
rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_EXCLUSIVE);
/* If the EXCLUSIVE lock was obtained, checkpoint and close the log. */
if( rc==SQLITE_OK ){
rc = sqlite3LogClose(pPager->pLog, pPager->fd,
(pPager->noSync ? 0 : pPager->sync_flags),