database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-08-07 02:42:48 +03:00
Code Activity

Initial code for incremental checkpoint in WAL mode. This check-in compiles

Browse Source 
on unix and runs as long as you do not engage WAL mode.  WAL mode crashes and
burns.  Consider this check-in a baseline implementation for getting the new
capability up and running.

FossilOrigin-Name: ef3ba7a17ff90674d702e5694b9e792851ab6998
This commit is contained in:
drh
2010-05-30 19:55:15 +00:00
parent a7a0c615d7
commit 73b64e4d2e
13 changed files with 811 additions and 617 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/pager.c
View File

@@ -1203,7 +1203,7 @@ static int pagerUseWal(Pager *pPager){
# define pagerRollbackWal(x) 0
# define pagerWalFrames(v,w,x,y,z) 0
# define pagerOpenWalIfPresent(z) SQLITE_OK
# define pagerOpenSnapshot(z) SQLITE_OK
# define pagerBeginReadTransaction(z) SQLITE_OK
#endif
/*
@@ -1238,7 +1238,7 @@ static void pager_unlock(Pager *pPager){
pPager->dbSizeValid = 0;
if( pagerUseWal(pPager) ){
sqlite3WalCloseSnapshot(pPager->pWal);
sqlite3WalEndReadTransaction(pPager->pWal);
}else{
rc = osUnlock(pPager->fd, NO_LOCK);
}
@@ -1437,7 +1437,7 @@ static int pager_end_transaction(Pager *pPager, int hasMaster){
sqlite3PcacheCleanAll(pPager->pPCache);
if( pagerUseWal(pPager) ){
rc2 = sqlite3WalWriteLock(pPager->pWal, 0);
rc2 = sqlite3WalEndWriteTransaction(pPager->pWal);
pPager->state = PAGER_SHARED;
/* If the connection was in locking_mode=exclusive mode but is no longer,
@@ -2362,15 +2362,20 @@ static int pagerWalFrames(
}
/*
** Open a WAL snapshot on the log file this pager is connected to.
** Begin a read transaction on the WAL.
**
** This routine used to be called "pagerOpenSnapshot()" because it essentially
** makes a snapshot of the database at the current point in time and preserves
** that snapshot for use by the reader in spite of concurrently changes by
** other writers or checkpointers.
*/
static int pagerOpenSnapshot(Pager *pPager){
static int pagerBeginReadTransaction(Pager *pPager){
int rc; /* Return code */
int changed = 0; /* True if cache must be reset */
assert( pagerUseWal(pPager) );
rc = sqlite3WalOpenSnapshot(pPager->pWal, &changed);
rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
if( rc==SQLITE_OK ){
int dummy;
if( changed ){
@@ -2428,7 +2433,7 @@ static int pagerOpenWalIfPresent(Pager *pPager){
pager_reset(pPager);
rc = sqlite3PagerOpenWal(pPager, 0);
if( rc==SQLITE_OK ){
rc = pagerOpenSnapshot(pPager);
rc = pagerBeginReadTransaction(pPager);
}
}else if( pPager->journalMode==PAGER_JOURNALMODE_WAL ){
pPager->journalMode = PAGER_JOURNALMODE_DELETE;
@@ -4002,7 +4007,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
}
if( pagerUseWal(pPager) ){
rc = pagerOpenSnapshot(pPager);
rc = pagerBeginReadTransaction(pPager);
}else if( pPager->state==PAGER_UNLOCK || isErrorReset ){
sqlite3_vfs * const pVfs = pPager->pVfs;
int isHotJournal = 0;
@@ -4561,7 +4566,7 @@ int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory){
** may copy data from the sub-journal into the database file as well
** as into the page cache. Which would be incorrect in WAL mode.
*/
rc = sqlite3WalWriteLock(pPager->pWal, 1);
rc = sqlite3WalBeginWriteTransaction(pPager->pWal);
if( rc==SQLITE_OK ){
pPager->dbOrigSize = pPager->dbSize;
pPager->state = PAGER_RESERVED;
@@ -5892,8 +5897,7 @@ int sqlite3PagerCheckpoint(Pager *pPager){
u8 *zBuf = (u8 *)pPager->pTmpSpace;
rc = sqlite3WalCheckpoint(pPager->pWal,
(pPager->noSync ? 0 : pPager->sync_flags),
pPager->pageSize, zBuf,
pPager->xBusyHandler, pPager->pBusyHandlerArg
pPager->pageSize, zBuf
);
}
return rc;