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

Fix for bug #94: Be sure to journal pages that are added to the freelist then

Browse Source 
removed from the freelist and reused during the same transaction. (CVS 660)

FossilOrigin-Name: db178646a01483d59e6f9af302e9bbe394956d93
This commit is contained in:
drh
2002-07-06 16:28:47 +00:00
parent 38640e15af
commit 8e298f92f6
3 changed files with 33 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
src/pager.c
View File

@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.47 2002/06/25 14:43:58 drh Exp $
** @(#) $Id: pager.c,v 1.48 2002/07/06 16:28:48 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
@@ -77,6 +77,7 @@ struct PgHdr {
char inJournal; /* TRUE if has been written to journal */
char inCkpt; /* TRUE if written to the checkpoint journal */
char dirty; /* TRUE if we need to write back changes */
char alwaysRollback; /* Ignore dont_rollback() calls if true */
/* SQLITE_PAGE_SIZE bytes of page data follow this header */
/* Pager.nExtra bytes of local data follow the page data */
};
@@ -252,14 +253,21 @@ static int pager_unwritelock(Pager *pPager){
pPager->journalOpen = 0;
sqliteOsDelete(pPager->zJournal);
rc = sqliteOsReadLock(&pPager->fd);
assert( rc==SQLITE_OK );
sqliteFree( pPager->aInJournal );
pPager->aInJournal = 0;
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
pPg->inJournal = 0;
pPg->dirty = 0;
}
pPager->state = SQLITE_READLOCK;
if( rc==SQLITE_OK ){
pPager->state = SQLITE_READLOCK;
}else{
/* This can only happen if a process does a BEGIN, then forks and the
** child process does the COMMIT. Because of the semantics of unix
** file locking, the unlock will fail.
*/
pPager->state = SQLITE_UNLOCK;
}
return rc;
}
@@ -1038,7 +1046,7 @@ int sqlitepager_begin(void *pData){
sqliteOsReadLock(&pPager->fd);
return SQLITE_NOMEM;
}
rc = sqliteOsOpenExclusive(pPager->zJournal, &pPager->jfd, 0);
rc = sqliteOsOpenExclusive(pPager->zJournal, &pPager->jfd,pPager->tempFile);
if( rc!=SQLITE_OK ){
sqliteFree(pPager->aInJournal);
pPager->aInJournal = 0;
@@ -1190,10 +1198,23 @@ int sqlitepager_iswriteable(void *pData){
** Tests show that this optimization, together with the
** sqlitepager_dont_rollback() below, more than double the speed
** of large INSERT operations and quadruple the speed of large DELETEs.
**
** When this routine is called, set the alwaysRollback flag to true.
** Subsequent calls to sqlitepager_dont_rollback() for the same page
** will thereafter be ignored. This is necessary to avoid a problem
** where a page with data is added to the freelist during one part of
** a transaction then removed from the freelist during a later part
** of the same transaction and reused for some other purpose. When it
** is first added to the freelist, this routine is called. When reused,
** the dont_rollback() routine is called. But because the page contains
** critical data, we still need to be sure it gets rolled back in spite
** of the dont_rollback() call.
*/
void sqlitepager_dont_write(Pager *pPager, Pgno pgno){
PgHdr *pPg;
pPg = pager_lookup(pPager, pgno);
pPg->alwaysRollback = 1;
if( pPg && pPg->dirty ){
if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
/* If this pages is the last page in the file and the file has grown
@@ -1221,6 +1242,7 @@ void sqlitepager_dont_rollback(void *pData){
Pager *pPager = pPg->pPager;
if( pPager->state!=SQLITE_WRITELOCK || pPager->journalOpen==0 ) return;
if( pPg->alwaysRollback ) return;
if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
assert( pPager->aInJournal!=0 );
pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);