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Changes for exclusive access mode. There are still some bugs. (CVS 3712)

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FossilOrigin-Name: b6c700370be29db2b974f9abd719c3e56abf8058
This commit is contained in:
danielk1977
2007-03-24 16:45:04 +00:00
parent e277be0545
commit 414834686c
9 changed files with 489 additions and 56 deletions
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102
src/pager.c
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@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.293 2007/03/23 18:12:07 danielk1977 Exp $
** @(#) $Id: pager.c,v 1.294 2007/03/24 16:45:05 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -285,8 +285,10 @@ struct Pager {
Pager *pNext; /* Linked list of pagers in this thread */
#endif
char *pTmpSpace; /* Pager.pageSize bytes of space for tmp use */
int doNotSync; /* While true, do not spill the cache */
u32 iChangeCount; /* Db change-counter for which cache is valid */
u8 doNotSync; /* Boolean. While true, do not spill the cache */
u8 exclusiveMode; /* Boolean. True if locking_mode==EXCLUSIVE */
u8 changeCountDone; /* Set after incrementing the change-counter */
};
/*
@@ -854,12 +856,15 @@ static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
** Unlock the database file.
*/
static void pager_unlock(Pager *pPager){
if( !MEMDB ){
sqlite3OsUnlock(pPager->fd, NO_LOCK);
pPager->dbSize = -1;
IOTRACE(("UNLOCK %p\n", pPager))
if( !pPager->exclusiveMode ){
if( !MEMDB ){
sqlite3OsUnlock(pPager->fd, NO_LOCK);
pPager->dbSize = -1;
IOTRACE(("UNLOCK %p\n", pPager))
}
pPager->state = PAGER_UNLOCK;
pPager->changeCountDone = 0;
}
pPager->state = PAGER_UNLOCK;
}
/*
@@ -873,7 +878,6 @@ static void pagerUnlockAndRollback(Pager *pPager){
sqlite3PagerRollback(pPager);
}
pager_unlock(pPager);
assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
}
@@ -902,28 +906,6 @@ static void pager_reset(Pager *pPager){
pPager->nRef = 0;
}
/*
** This function resets the various pager flags to their initial
** state but does not discard the cached content.
*/
static void pagerSoftReset(Pager *pPager){
PgHdr *pPg;
assert(pPager->pStmt==0);
assert(pPager->nRef==0);
assert(pPager->pFirstSynced==pPager->pFirst);
assert(pPager->aInJournal==0);
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
assert( pPg->nRef==0 );
pPg->inJournal = 0;
pPg->inStmt = 0;
pPg->dirty = 0;
pPg->needSync = 0;
pPg->alwaysRollback = 0;
}
}
/*
** When this routine is called, the pager has the journal file open and
** a RESERVED or EXCLUSIVE lock on the database. This routine releases
@@ -936,7 +918,7 @@ static void pagerSoftReset(Pager *pPager){
*/
static int pager_unwritelock(Pager *pPager){
PgHdr *pPg;
int rc;
int rc = SQLITE_OK;
assert( !MEMDB );
if( pPager->state<PAGER_RESERVED ){
return SQLITE_OK;
@@ -947,15 +929,22 @@ static int pager_unwritelock(Pager *pPager){
pPager->stmtOpen = 0;
}
if( pPager->journalOpen ){
sqlite3OsClose(&pPager->jfd);
pPager->journalOpen = 0;
sqlite3OsDelete(pPager->zJournal);
if( pPager->exclusiveMode ){
sqlite3OsTruncate(pPager->jfd, 0);
sqlite3OsSeek(pPager->jfd, 0);
pPager->journalOff = 0;
}else{
sqlite3OsClose(&pPager->jfd);
pPager->journalOpen = 0;
sqlite3OsDelete(pPager->zJournal);
}
sqliteFree( pPager->aInJournal );
pPager->aInJournal = 0;
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
pPg->inJournal = 0;
pPg->dirty = 0;
pPg->needSync = 0;
pPg->alwaysRollback = 0;
#ifdef SQLITE_CHECK_PAGES
pPg->pageHash = pager_pagehash(pPg);
#endif
@@ -967,9 +956,18 @@ static int pager_unwritelock(Pager *pPager){
assert( pPager->aInJournal==0 );
assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
}
rc = sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
pPager->state = PAGER_SHARED;
pPager->origDbSize = 0;
if( !pPager->exclusiveMode ){
rc = sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
pPager->state = PAGER_SHARED;
pPager->origDbSize = 0;
}else{
sqlite3PagerPagecount(pPager);
pPager->origDbSize = pPager->dbSize;
pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
if( !pPager->aInJournal ){
rc = SQLITE_NOMEM;
}
}
pPager->setMaster = 0;
pPager->needSync = 0;
pPager->pFirstSynced = pPager->pFirst;
@@ -1109,6 +1107,11 @@ static int pager_playback_one_page(Pager *pPager, OsFile *jfd, int useCksum){
pPg->pageHash = pager_pagehash(pPg);
#endif
CODEC1(pPager, pData, pPg->pgno, 3);
/* If this was page 1, then restore the value of Pager.iChangeCount */
if( pgno==1 ){
pPager->iChangeCount = retrieve32bits(pPg, 24);
}
}
return rc;
}
@@ -1199,6 +1202,7 @@ delmaster_out:
return rc;
}
#if 0
/*
** Make every page in the cache agree with what is on disk. In other words,
** reread the disk to reset the state of the cache.
@@ -1242,6 +1246,7 @@ static int pager_reload_cache(Pager *pPager){
pPager->pDirty = 0;
return rc;
}
#endif
/*
** Truncate the main file of the given pager to the number of pages
@@ -2126,6 +2131,7 @@ int sqlite3PagerClose(Pager *pPager){
disable_simulated_io_errors();
pPager->errCode = 0;
pPager->exclusiveMode = 0;
pager_reset(pPager);
pagerUnlockAndRollback(pPager);
enable_simulated_io_errors();
@@ -2734,8 +2740,6 @@ static int pagerSharedLock(Pager *pPager){
pPager->nRef--;
if( iChangeCount!=pPager->iChangeCount ){
pager_reset(pPager);
}else{
pagerSoftReset(pPager);
}
pPager->iChangeCount = iChangeCount;
}
@@ -3610,6 +3614,8 @@ int sqlite3PagerRollback(Pager *pPager){
PgHistory *pHist;
assert( !p->alwaysRollback );
if( !p->dirty ){
assert( p->inJournal==0 );
assert( p->inStmt==0 );
assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pOrig );
assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pStmt );
continue;
@@ -3890,6 +3896,7 @@ static int pager_incr_changecounter(Pager *pPager){
/* Release the page reference. */
sqlite3PagerUnref(pPgHdr);
pPager->changeCountDone = 1;
return SQLITE_OK;
}
@@ -4098,6 +4105,23 @@ void *sqlite3PagerGetExtra(DbPage *pPg){
return (pPager?PGHDR_TO_EXTRA(pPg, pPager):0);
}
/*
** Get/set the locking-mode for this pager. Parameter eMode must be one
** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or
** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
** the locking-mode is set to the value specified.
**
** The returned value is either PAGER_LOCKINGMODE_NORMAL or
** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
** locking-mode.
*/
int sqlite3PagerLockingMode(Pager *pPager, int eMode){
if( eMode>=0 ){
pPager->exclusiveMode = eMode;
}
return (int)pPager->exclusiveMode;
}
#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
/*
** Return the current state of the file lock for the given pager.