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If a page is made eligible for recycling when more than the configured maximum number of pages are allocated, free it immediately instead of adding it to the LRU list. (CVS 5638)

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FossilOrigin-Name: 4b12922dcb4547bf3a7276d0542b2e1d12ad338d
This commit is contained in:
danielk1977
2008-08-29 09:10:02 +00:00
parent 8b213899e8
commit 062d4cb0ae
6 changed files with 234 additions and 15 deletions
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45
src/pcache.c
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@@ -11,7 +11,7 @@
*************************************************************************
** This file implements that page cache.
**
** @(#) $Id: pcache.c,v 1.23 2008/08/28 17:46:19 drh Exp $
** @(#) $Id: pcache.c,v 1.24 2008/08/29 09:10:03 danielk1977 Exp $
*/
#include "sqliteInt.h"
@@ -748,7 +748,13 @@ void sqlite3PcacheRelease(PgHdr *p){
if( (p->flags&PGHDR_DIRTY)==0 ){
pCache->nPinned--;
pcacheEnterMutex();
pcacheAddToLruList(p);
if( pcache.nCurrentPage>pcache.nMaxPage ){
pcacheRemoveFromList(&pCache->pClean, p);
pcacheRemoveFromHash(p);
pcachePageFree(p);
}else{
pcacheAddToLruList(p);
}
pcacheExitMutex();
}else{
/* Move the page to the head of the caches dirty list. */
@@ -930,6 +936,17 @@ void sqlite3PcacheTruncate(PCache *pCache, Pgno pgno){
pcacheExitMutex();
}
/*
** If there are currently more than pcache.nMaxPage pages allocated, try
** to recycle pages to reduce the number allocated to pcache.nMaxPage.
*/
static void pcacheEnforceMaxPage(){
PgHdr *p;
assert( sqlite3_mutex_held(pcache.mutex) );
while( pcache.nCurrentPage>pcache.nMaxPage && (p = pcacheRecyclePage()) ){
pcachePageFree(p);
}
}
/*
** Close a cache.
@@ -942,9 +959,9 @@ void sqlite3PcacheClose(PCache *pCache){
if( pCache->bPurgeable ){
pcache.nMaxPage -= pCache->nMax;
pcache.nMinPage -= pCache->nMin;
pcacheEnforceMaxPage();
}
sqlite3_free(pCache->apHash);
pcacheExitMutex();
}
@@ -1193,6 +1210,7 @@ void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
pcacheEnterMutex();
pcache.nMaxPage -= pCache->nMax;
pcache.nMaxPage += mxPage;
pcacheEnforceMaxPage();
pcacheExitMutex();
}
pCache->nMax = mxPage;
@@ -1222,3 +1240,24 @@ int sqlite3PcacheReleaseMemory(int nReq){
return nFree;
}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */
#ifdef SQLITE_TEST
void sqlite3PcacheStats(
int *pnCurrent,
int *pnMax,
int *pnMin,
int *pnRecyclable
){
PgHdr *p;
int nRecyclable = 0;
for(p=pcache.pLruHead; p; p=p->pNextLru){
nRecyclable++;
}
*pnCurrent = pcache.nCurrentPage;
*pnMax = pcache.nMaxPage;
*pnMin = pcache.nMinPage;
*pnRecyclable = nRecyclable;
}
#endif