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Support compile-time option SQLITE_OMIT_WAL, for building without WAL support.

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FossilOrigin-Name: 9b230c43dfa112e3e1589f9775926807bd36b36e
This commit is contained in:
dan
2010-05-01 16:40:20 +00:00
parent 057f1ecddb
commit 5cf53537a8
22 changed files with 267 additions and 133 deletions
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219
src/pager.c
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@@ -399,7 +399,9 @@ struct Pager {
char *pTmpSpace; /* Pager.pageSize bytes of space for tmp use */
PCache *pPCache; /* Pointer to page cache object */
sqlite3_backup *pBackup; /* Pointer to list of ongoing backup processes */
#ifndef SQLITE_OMIT_WAL
Wal *pWal; /* Write-ahead log used by "journal_mode=wal" */
#endif
};
/*
@@ -1192,9 +1194,16 @@ static int addToSavepointBitvecs(Pager *pPager, Pgno pgno){
** Return true if this pager uses a write-ahead log instead of the usual
** rollback journal. Otherwise false.
*/
#ifndef SQLITE_OMIT_WAL
static int pagerUseWal(Pager *pPager){
return (pPager->pWal!=0);
}
#else
# define pagerUseWal(x) 0
# define pagerRollbackWal(x) 0
# define pagerWalFrames(v,w,x,y,z) 0
# define pagerOpenWalIfPresent(z) SQLITE_OK
#endif
/*
** Unlock the database file. This function is a no-op if the pager
@@ -2242,6 +2251,7 @@ static int readDbPage(PgHdr *pPg){
return rc;
}
#ifndef SQLITE_OMIT_WAL
/*
** This function is invoked once for each page that has already been
** written into the log file when a WAL transaction is rolled back.
@@ -2311,6 +2321,115 @@ static int pagerRollbackWal(Pager *pPager){
return rc;
}
/*
** This function is a wrapper around sqlite3WalFrames(). As well as logging
** the contents of the list of pages headed by pList (connected by pDirty),
** this function notifies any active backup processes that the pages have
** changed.
*/
static int pagerWalFrames(
Pager *pPager, /* Pager object */
PgHdr *pList, /* List of frames to log */
Pgno nTruncate, /* Database size after this commit */
int isCommit, /* True if this is a commit */
int sync_flags /* Flags to pass to OsSync() (or 0) */
){
int rc; /* Return code */
assert( pPager->pWal );
rc = sqlite3WalFrames(pPager->pWal,
pPager->pageSize, pList, nTruncate, isCommit, sync_flags
);
if( rc==SQLITE_OK && pPager->pBackup ){
PgHdr *p;
for(p=pList; p; p=p->pDirty){
sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
}
}
return rc;
}
/*
** Open a WAL snapshot on the log file this pager is connected to.
*/
static int pagerOpenSnapshot(Pager *pPager){
int rc; /* Return code */
int changed = 0; /* True if cache must be reset */
assert( pagerUseWal(pPager) );
rc = sqlite3WalOpenSnapshot(pPager->pWal, &changed);
if( rc==SQLITE_OK ){
int dummy;
if( changed ){
pager_reset(pPager);
assert( pPager->errCode || pPager->dbSizeValid==0 );
}
rc = sqlite3PagerPagecount(pPager, &dummy);
}
pPager->state = PAGER_SHARED;
return rc;
}
/*
** Check if the *-wal file that corresponds to the database opened by pPager
** exists. Assuming no error occurs, set *pExists to 1 if the file exists,
** or 0 otherwise and return SQLITE_OK. If an IO or OOM error occurs, return
** an SQLite error code.
*/
static int pagerHasWAL(Pager *pPager, int *pExists){
int rc; /* Return code */
if( !pPager->tempFile ){
char *zWal = sqlite3_mprintf("%s-wal", pPager->zFilename);
if( !zWal ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3OsAccess(pPager->pVfs, zWal, SQLITE_ACCESS_EXISTS, pExists);
sqlite3_free(zWal);
}
}else{
rc = SQLITE_OK;
*pExists = 0;
}
return rc;
}
/*
** Check if the *-wal file that corresponds to the database opened by pPager
** exists. If it does, open the pager in WAL mode. Otherwise, if no error
** occurs, make sure Pager.journalMode is not set to PAGER_JOURNALMODE_WAL.
** If an IO or OOM error occurs, return an SQLite error code.
**
** If the WAL file is opened, also open a snapshot (read transaction).
**
** The caller must hold a SHARED lock on the database file to call this
** 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 pagerOpenWalIfPresent(Pager *pPager){
int rc = SQLITE_OK;
if( !pPager->tempFile ){
int isWal; /* True if WAL file exists */
rc = pagerHasWAL(pPager, &isWal);
if( rc==SQLITE_OK ){
if( isWal ){
pager_reset(pPager);
rc = sqlite3PagerOpenWal(pPager, 0);
if( rc==SQLITE_OK ){
rc = pagerOpenSnapshot(pPager);
}
}else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
pPager->journalMode = PAGER_JOURNALMODE_DELETE;
}
}
}
return rc;
}
#endif
/*
** Playback savepoint pSavepoint. Or, if pSavepoint==NULL, then playback
** the entire master journal file. The case pSavepoint==NULL occurs when
@@ -2934,10 +3053,12 @@ int sqlite3PagerClose(Pager *pPager){
sqlite3BeginBenignMalloc();
pPager->errCode = 0;
pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
sqlite3WalClose(pPager->pWal, pPager->fd,
(pPager->noSync ? 0 : pPager->sync_flags), pTmp
);
pPager->pWal = 0;
#endif
pager_reset(pPager);
if( MEMDB ){
pager_unlock(pPager);
@@ -3280,34 +3401,6 @@ static int subjournalPage(PgHdr *pPg){
return rc;
}
/*
** This function is a wrapper around sqlite3WalFrames(). As well as logging
** the contents of the list of pages headed by pList (connected by pDirty),
** this function notifies any active backup processes that the pages have
** changed.
*/
static int pagerWalFrames(
Pager *pPager, /* Pager object */
PgHdr *pList, /* List of frames to log */
Pgno nTruncate, /* Database size after this commit */
int isCommit, /* True if this is a commit */
int sync_flags /* Flags to pass to OsSync() (or 0) */
){
int rc; /* Return code */
assert( pPager->pWal );
rc = sqlite3WalFrames(pPager->pWal,
pPager->pageSize, pList, nTruncate, isCommit, sync_flags
);
if( rc==SQLITE_OK && pPager->pBackup ){
PgHdr *p;
for(p=pList; p; p=p->pDirty){
sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
}
}
return rc;
}
/*
** This function is called by the pcache layer when it has reached some
** soft memory limit. The first argument is a pointer to a Pager object
@@ -3819,55 +3912,6 @@ static int hasHotJournal(Pager *pPager, int *pExists){
return rc;
}
/*
** Check if the *-wal file that corresponds to the database opened by pPager
** exists. Assuming no error occurs, set *pExists to 1 if the file exists,
** or 0 otherwise and return SQLITE_OK. If an IO or OOM error occurs, return
** an SQLite error code.
**
** The caller must hold a SHARED lock on the database file to call this
** 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 */
if( !pPager->tempFile ){
char *zWal = sqlite3_mprintf("%s-wal", pPager->zFilename);
if( !zWal ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3OsAccess(pPager->pVfs, zWal, SQLITE_ACCESS_EXISTS, pExists);
sqlite3_free(zWal);
}
}else{
rc = SQLITE_OK;
*pExists = 0;
}
return rc;
}
static int pagerOpenSnapshot(Pager *pPager){
int rc; /* Return code */
int changed = 0; /* True if cache must be reset */
assert( pagerUseWal(pPager) );
rc = sqlite3WalOpenSnapshot(pPager->pWal, &changed);
if( rc==SQLITE_OK ){
int dummy;
if( changed ){
pager_reset(pPager);
assert( pPager->errCode || pPager->dbSizeValid==0 );
}
rc = sqlite3PagerPagecount(pPager, &dummy);
}
pPager->state = PAGER_SHARED;
return rc;
}
/*
** This function is called to obtain a shared lock on the database file.
** It is illegal to call sqlite3PagerAcquire() until after this function
@@ -3926,7 +3970,6 @@ int sqlite3PagerSharedLock(Pager *pPager){
}else if( pPager->state==PAGER_UNLOCK || isErrorReset ){
sqlite3_vfs * const pVfs = pPager->pVfs;
int isHotJournal = 0;
int isWal = 0;
assert( !MEMDB );
assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
if( pPager->noReadlock ){
@@ -4081,19 +4124,10 @@ int sqlite3PagerSharedLock(Pager *pPager){
}
assert( pPager->exclusiveMode || pPager->state==PAGER_SHARED );
rc = pagerHasWAL(pPager, &isWal);
if( rc!=SQLITE_OK ){
goto failed;
}
if( isWal ){
pager_reset(pPager);
rc = sqlite3PagerOpenWal(pPager, 0);
if( rc==SQLITE_OK ){
rc = pagerOpenSnapshot(pPager);
}
}else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
pPager->journalMode = PAGER_JOURNALMODE_DELETE;
}
/* If there is a WAL file in the file-system, open this database in WAL
** mode. Otherwise, the following function call is a no-op.
*/
rc = pagerOpenWalIfPresent(pPager);
}
failed:
@@ -5789,6 +5823,7 @@ sqlite3_backup **sqlite3PagerBackupPtr(Pager *pPager){
return &pPager->pBackup;
}
#ifndef SQLITE_OMIT_WAL
/*
** This function is called when the user invokes "PRAGMA checkpoint".
*/
@@ -5836,7 +5871,6 @@ int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen){
return rc;
}
/*
** This function is called to close the connection to the log file prior
** to switching from WAL to rollback mode.
@@ -5881,5 +5915,6 @@ int sqlite3PagerCloseWal(Pager *pPager){
}
return rc;
}
#endif
#endif /* SQLITE_OMIT_DISKIO */