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Overview
| Comment: | Always hold the MEM2 mutex when initially marking a pager as in use by its database connection. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | branch-3.5.9 |
| Files: | files | file ages | folders |
| SHA1: |
622c17177af6851fec11bdec8fb6246c |
| User & Date: | drh 2010-01-30 22:28:47.000 |
Context
|
2010-01-30
| ||
| 23:08 | The iInUseDB and iInUseMM variables do not need to be volatile. (Leaf check-in: bb18f57852 user: drh tags: branch-3.5.9) | |
| 22:28 | Always hold the MEM2 mutex when initially marking a pager as in use by its database connection. (check-in: 622c17177a user: drh tags: branch-3.5.9) | |
| 19:17 | Avoid a race condition in the sqlite3_release_memory() logic within pager.c. (check-in: a718e66347 user: drh tags: branch-3.5.9) | |
Changes
Changes to src/pager.c.
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**
** The pagerMutexHeld(X) macro is for sanity checking. This macro verifies
** that the database-connection mutex is held for pager X and asserts if it
** is not.
*/
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
static void pagerEnter(Pager *p){
| > | | < | 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 |
**
** The pagerMutexHeld(X) macro is for sanity checking. This macro verifies
** that the database-connection mutex is held for pager X and asserts if it
** is not.
*/
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
static void pagerEnter(Pager *p){
if( p->iInUseDB>0 ){
p->iInUseDB++;
}else{
#ifndef SQLITE_MUTEX_NOOP
sqlite3_mutex *mutex;
mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM2);
#endif
sqlite3_mutex_enter(mutex);
assert( p->iInUseMM==0 );
p->iInUseDB = 1;
sqlite3_mutex_leave(mutex);
}
}
static void pagerLeave(Pager *p){
|
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/* If pPg==0, then the block above has failed to find a page to
** recycle. In this case return early - no further memory will
** be released.
*/
if( !pPg ) break;
pPager = pPg->pPager;
savedBusy = pPager->pBusyHandler;
pPager->pBusyHandler = 0;
rc = pager_recycle(pPager, &pPg);
pPager->pBusyHandler = savedBusy;
if( rc==SQLITE_OK ){
/* We've found a page to free. At this point the page has been
** removed from the page hash-table, free-list and synced-list
** (pFirstSynced). It is still in the all pages (pAll) list.
** Remove it from this list before freeing.
**
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/* If pPg==0, then the block above has failed to find a page to
** recycle. In this case return early - no further memory will
** be released.
*/
if( !pPg ) break;
pPager = pPg->pPager;
assert( pPager->iInUseDB==0 );
savedBusy = pPager->pBusyHandler;
pPager->pBusyHandler = 0;
rc = pager_recycle(pPager, &pPg);
assert( pPager->iInUseDB==0 );
pPager->pBusyHandler = savedBusy;
if( rc==SQLITE_OK ){
/* We've found a page to free. At this point the page has been
** removed from the page hash-table, free-list and synced-list
** (pFirstSynced). It is still in the all pages (pAll) list.
** Remove it from this list before freeing.
**
|
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