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Fix a resource leak introduced by the change-counter optimisation. Also add some test coverage. (CVS 3790)

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FossilOrigin-Name: ba0538a4977aefd6645554f1989f0a98b540b9cd
This commit is contained in:
danielk1977
2007-04-02 05:07:47 +00:00
parent 3057aaaa9c
commit 241687280b
9 changed files with 209 additions and 70 deletions
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141
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 1.313 2007/04/01 23:49:52 drh Exp $
** @(#) $Id: pager.c,v 1.314 2007/04/02 05:07:47 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -2389,9 +2389,16 @@ static PgHdr *merge_pagelist(PgHdr *pA, PgHdr *pB){
** connected by pDirty pointers. The pPrevDirty pointers are
** corrupted by this sort.
*/
#define N_SORT_BUCKET 25
#define N_SORT_BUCKET_ALLOC 25
#define N_SORT_BUCKET 25
#ifdef SQLITE_TEST
int sqlite3_pager_n_sort_bucket = 0;
#undef N_SORT_BUCKET
#define N_SORT_BUCKET \
(sqlite3_pager_n_sort_bucket?sqlite3_pager_n_sort_bucket:N_SORT_BUCKET_ALLOC)
#endif
static PgHdr *sort_pagelist(PgHdr *pIn){
PgHdr *a[N_SORT_BUCKET], *p;
PgHdr *a[N_SORT_BUCKET_ALLOC], *p;
int i;
memset(a, 0, sizeof(a));
while( pIn ){
@@ -2408,6 +2415,11 @@ static PgHdr *sort_pagelist(PgHdr *pIn){
}
}
if( i==N_SORT_BUCKET-1 ){
/* Coverage: To get here, there need to be 2^(N_SORT_BUCKET)
** elements in the input list. This is possible, but impractical.
** Testing this line is the point of global variable
** sqlite3_pager_n_sort_bucket.
*/
a[i] = merge_pagelist(a[i], p);
}
}
@@ -2591,7 +2603,9 @@ static int pager_recycle(Pager *pPager, int syncOk, PgHdr **ppPg){
/* Unlink the old page from the free list and the hash table
*/
unlinkPage(pPg);
TEST_INCR(pPager->nOvfl);
if( pPg && pPg->pgno!=0 ){
TEST_INCR(pPager->nOvfl);
}
*ppPg = pPg;
return SQLITE_OK;
@@ -2771,9 +2785,32 @@ static int pagerSharedLock(Pager *pPager){
}
if( pPager->pAll ){
/* The shared-lock has just been acquired on the database file
** and there are already pages in the cache (from a previous
** read or write transaction). If the value of the change-counter
** stored in Pager.iChangeCount matches that found on page 1 of
** the database file, then no database changes have occured since
** the cache was last valid and it is safe to retain the cached
** pages. Otherwise, if Pager.iChangeCount does not match the
** change-counter on page 1 of the file, the current cache contents
** must be discarded.
*/
PgHdr *pPage1 = pager_lookup(pPager, 1);
if( pPage1 ){
unlinkHashChain(pPager, pPage1);
unlinkPage(pPage1);
assert( pPager->pFirst==pPager->pFirstSynced );
pPage1->pNextFree = pPager->pFirst;
if( pPager->pFirst ){
pPager->pFirst->pPrevFree = pPage1;
}else{
assert( !pPager->pLast );
pPager->pLast = pPage1;
}
pPager->pFirst = pPage1;
pPager->pFirstSynced = pPage1;
}
assert( !pager_lookup(pPager, 1) );
@@ -2802,6 +2839,60 @@ static int pagerSharedLock(Pager *pPager){
return rc;
}
/*
** Allocate or recycle space for a single page.
*/
static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
int rc = SQLITE_OK;
PgHdr *pPg;
if( !(pPager->pFirstSynced && pPager->pFirstSynced->pgno==0) && (
pPager->nPage<pPager->mxPage || pPager->pFirst==0 || MEMDB ||
(pPager->pFirstSynced==0 && pPager->doNotSync)
) ){
/* Create a new page */
if( pPager->nPage>=pPager->nHash ){
pager_resize_hash_table(pPager,
pPager->nHash<256 ? 256 : pPager->nHash*2);
if( pPager->nHash==0 ){
rc = SQLITE_NOMEM;
goto pager_allocate_out;
}
}
pPg = sqliteMallocRaw( sizeof(*pPg) + pPager->pageSize
+ sizeof(u32) + pPager->nExtra
+ MEMDB*sizeof(PgHistory) );
if( pPg==0 ){
rc = SQLITE_NOMEM;
goto pager_allocate_out;
}
memset(pPg, 0, sizeof(*pPg));
if( MEMDB ){
memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory));
}
pPg->pPager = pPager;
pPg->pNextAll = pPager->pAll;
pPager->pAll = pPg;
pPager->nPage++;
if( pPager->nPage>pPager->nMaxPage ){
assert( pPager->nMaxPage==(pPager->nPage-1) );
pPager->nMaxPage++;
}
}else{
/* Recycle an existing page with a zero ref-count. */
rc = pager_recycle(pPager, 1, &pPg);
if( rc!=SQLITE_OK ){
goto pager_allocate_out;
}
assert( pPager->state>=SHARED_LOCK );
assert(pPg);
}
*ppPg = pPg;
pager_allocate_out:
return rc;
}
/*
** Acquire a page.
**
@@ -2867,43 +2958,11 @@ int sqlite3PagerAcquire(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag){
int nMax;
int h;
TEST_INCR(pPager->nMiss);
if( pPager->nPage<pPager->mxPage || pPager->pFirst==0 || MEMDB ||
(pPager->pFirstSynced==0 && pPager->doNotSync)
){
/* Create a new page */
if( pPager->nPage>=pPager->nHash ){
pager_resize_hash_table(pPager,
pPager->nHash<256 ? 256 : pPager->nHash*2);
if( pPager->nHash==0 ){
return SQLITE_NOMEM;
}
}
pPg = sqliteMallocRaw( sizeof(*pPg) + pPager->pageSize
+ sizeof(u32) + pPager->nExtra
+ MEMDB*sizeof(PgHistory) );
if( pPg==0 ){
return SQLITE_NOMEM;
}
memset(pPg, 0, sizeof(*pPg));
if( MEMDB ){
memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory));
}
pPg->pPager = pPager;
pPg->pNextAll = pPager->pAll;
pPager->pAll = pPg;
pPager->nPage++;
if( pPager->nPage>pPager->nMaxPage ){
assert( pPager->nMaxPage==(pPager->nPage-1) );
pPager->nMaxPage++;
}
}else{
rc = pager_recycle(pPager, 1, &pPg);
if( rc!=SQLITE_OK ){
return rc;
}
assert( pPager->state>=SHARED_LOCK );
assert(pPg);
rc = pagerAllocatePage(pPager, &pPg);
if( rc!=SQLITE_OK ){
return rc;
}
pPg->pgno = pgno;
if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
sqlite3CheckMemory(pPager->aInJournal, pgno/8);