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Overview
| Comment: | Omit unnecessary fstat() calls for determining the database file size, resulting in smaller and faster code. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
dd61c736775c53450821327495276485 |
| User & Date: | drh 2017-05-29 17:59:29 |
Context
|
2017-05-29
| ||
| 22:44 | More efficient error handling and reset in the binding mechanism. (check-in: 9a3e3b34 user: drh tags: trunk) | |
| 17:59 | Omit unnecessary fstat() calls for determining the database file size, resulting in smaller and faster code. (check-in: dd61c736 user: drh tags: trunk) | |
| 17:43 | Fix an issue with OPT_FEATURE_FLAGS in configure.ac. (check-in: 43ce3bd3 user: drh tags: trunk) | |
| 16:45 | Avoid unnecessary fstat() calls to determine the database size when transitioning into a read transaction on a rollback-mode database. (Closed-Leaf check-in: 6c3476b5 user: drh tags: io-opt) | |
Changes
Changes to src/pager.c.
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static int pagerOpenWalIfPresent(Pager *pPager){
int rc = SQLITE_OK;
assert( pPager->eState==PAGER_OPEN );
assert( pPager->eLock>=SHARED_LOCK );
if( !pPager->tempFile ){
int isWal; /* True if WAL file exists */
Pgno nPage; /* Size of the database file */
rc = pagerPagecount(pPager, &nPage);
if( rc ) return rc;
if( nPage==0 ){
rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
if( rc==SQLITE_IOERR_DELETE_NOENT ) rc = SQLITE_OK;
isWal = 0;
}else{
rc = sqlite3OsAccess(
pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
);
}
if( rc==SQLITE_OK ){
if( isWal ){
testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
rc = sqlite3PagerOpenWal(pPager, 0);
}else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
pPager->journalMode = PAGER_JOURNALMODE_DELETE;
}
}
}
return rc;
}
................................................................................
** other bytes change randomly with each file change when
** a codec is in use.
**
** There is a vanishingly small chance that a change will not be
** detected. The chance of an undetected change is so small that
** it can be neglected.
*/
Pgno nPage = 0;
char dbFileVers[sizeof(pPager->dbFileVers)];
rc = pagerPagecount(pPager, &nPage);
if( rc ) goto failed;
if( nPage>0 ){
IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
goto failed;
}
}else{
memset(dbFileVers, 0, sizeof(dbFileVers));
}
if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
pager_reset(pPager);
/* Unmap the database file. It is possible that external processes
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static int pagerOpenWalIfPresent(Pager *pPager){
int rc = SQLITE_OK;
assert( pPager->eState==PAGER_OPEN );
assert( pPager->eLock>=SHARED_LOCK );
if( !pPager->tempFile ){
int isWal; /* True if WAL file exists */
rc = sqlite3OsAccess(
pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
);
if( rc==SQLITE_OK ){
if( isWal ){
Pgno nPage; /* Size of the database file */
rc = pagerPagecount(pPager, &nPage);
if( rc ) return rc;
if( nPage==0 ){
rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
}else{
testcase( sqlite3PcachePagecount(pPager->pPCache)==0 );
rc = sqlite3PagerOpenWal(pPager, 0);
}
}else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
pPager->journalMode = PAGER_JOURNALMODE_DELETE;
}
}
}
return rc;
}
................................................................................
** other bytes change randomly with each file change when
** a codec is in use.
**
** There is a vanishingly small chance that a change will not be
** detected. The chance of an undetected change is so small that
** it can be neglected.
*/
char dbFileVers[sizeof(pPager->dbFileVers)];
IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
if( rc!=SQLITE_OK ){
if( rc!=SQLITE_IOERR_SHORT_READ ){
goto failed;
}
memset(dbFileVers, 0, sizeof(dbFileVers));
}
if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
pager_reset(pPager);
/* Unmap the database file. It is possible that external processes
|