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Allocate page cache headers and page cache data buffers separately.

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The data buffer will be a power of two in size and this gives some
malloc implementation additional optimization opportunitites. (CVS 4409)

FossilOrigin-Name: 2b755defe51a565a2b6ace58381d6e91f6f17db8
This commit is contained in:
drh
2007-09-06 22:19:14 +00:00
parent 24e824c4eb
commit bf4bca541e
5 changed files with 61 additions and 48 deletions
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63
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 1.385 2007/09/03 15:19:35 drh Exp $
** @(#) $Id: pager.c,v 1.386 2007/09/06 22:19:15 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -271,12 +271,11 @@ struct PgHdr {
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
PagerLruLink gfree; /* Global list of nRef==0 pages */
#endif
u32 notUsed; /* Buffer space */
#ifdef SQLITE_CHECK_PAGES
u32 pageHash;
#endif
/* pPager->pageSize bytes of page data follow this header */
/* Pager.nExtra bytes of local data follow the page data */
void *pData; /* Page data */
/* Pager.nExtra bytes of local data appended to this header */
};
/*
@@ -313,11 +312,10 @@ struct PgHistory {
** Convert a pointer to a PgHdr into a pointer to its data
** and back again.
*/
#define PGHDR_TO_DATA(P) ((void*)(&(P)[1]))
#define DATA_TO_PGHDR(D) (&((PgHdr*)(D))[-1])
#define PGHDR_TO_EXTRA(G,P) ((void*)&((char*)(&(G)[1]))[(P)->pageSize])
#define PGHDR_TO_DATA(P) ((P)->pData)
#define PGHDR_TO_EXTRA(G,P) ((void*)&((G)[1]))
#define PGHDR_TO_HIST(P,PGR) \
((PgHistory*)&((char*)(&(P)[1]))[(PGR)->pageSize+(PGR)->nExtra])
((PgHistory*)&((char*)(&(P)[1]))[(PGR)->nExtra])
/*
** A open page cache is an instance of the following structure.
@@ -1245,6 +1243,7 @@ static void pager_reset(Pager *pPager){
PAGER_INCR(sqlite3_pager_pgfree_count);
pNext = pPg->pNextAll;
lruListRemove(pPg);
sqlite3_free(pPg->pData);
sqlite3_free(pPg);
}
assert(pPager->lru.pFirst==0);
@@ -2495,6 +2494,7 @@ static void pager_truncate_cache(Pager *pPager){
PAGER_INCR(sqlite3_pager_pgfree_count);
unlinkPage(pPg);
makeClean(pPg);
sqlite3_free(pPg->pData);
sqlite3_free(pPg);
pPager->nPage--;
}
@@ -3158,6 +3158,7 @@ int sqlite3PagerReleaseMemory(int nReq){
);
IOTRACE(("PGFREE %p %d *\n", pPager, pPg->pgno));
PAGER_INCR(sqlite3_pager_pgfree_count);
sqlite3_free(pPg->pData);
sqlite3_free(pPg);
pPager->nPage--;
}else{
@@ -3394,6 +3395,7 @@ static int pagerSharedLock(Pager *pPager){
static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
int rc = SQLITE_OK;
PgHdr *pPg;
void *pData;
/* Create a new PgHdr if any of the four conditions defined
** above are met: */
@@ -3411,9 +3413,15 @@ static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
}
}
pagerLeave(pPager);
pPg = sqlite3_malloc( sizeof(*pPg) + pPager->pageSize
+ sizeof(u32) + pPager->nExtra
pPg = sqlite3_malloc( sizeof(*pPg) + sizeof(u32) + pPager->nExtra
+ MEMDB*sizeof(PgHistory) );
if( pPg ){
pData = sqlite3_malloc( pPager->pageSize );
if( pData==0 ){
sqlite3_free(pPg);
pPg = 0;
}
}
pagerEnter(pPager);
if( pPg==0 ){
rc = SQLITE_NOMEM;
@@ -3423,6 +3431,7 @@ static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
if( MEMDB ){
memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory));
}
pPg->pData = pData;
pPg->pPager = pPager;
pPg->pNextAll = pPager->pAll;
pPager->pAll = pPg;
@@ -3987,7 +3996,6 @@ static int pager_write(PgHdr *pPg){
*/
if( !pPg->inJournal && (pPager->useJournal || MEMDB) ){
if( (int)pPg->pgno <= pPager->origDbSize ){
int szPg;
if( MEMDB ){
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
PAGERTRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
@@ -3997,8 +4005,8 @@ static int pager_write(PgHdr *pPg){
memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize);
}
}else{
u32 cksum, saved;
char *pData2, *pEnd;
u32 cksum;
char *pData2;
/* We should never write to the journal file the page that
** contains the database locks. The following assert verifies
@@ -4006,20 +4014,21 @@ static int pager_write(PgHdr *pPg){
assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
cksum = pager_cksum(pPager, (u8*)pData2);
pEnd = pData2 + pPager->pageSize;
pData2 -= 4;
saved = *(u32*)pEnd;
put32bits(pEnd, cksum);
szPg = pPager->pageSize+8;
put32bits(pData2, pPg->pgno);
rc = sqlite3OsWrite(pPager->jfd, pData2, szPg, pPager->journalOff);
IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
rc = write32bits(pPager->jfd, pPager->journalOff, pPg->pgno);
if( rc==SQLITE_OK ){
rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize,
pPager->journalOff + 4);
pPager->journalOff += pPager->pageSize+4;
}
if( rc==SQLITE_OK ){
rc = write32bits(pPager->jfd, pPager->journalOff, cksum);
pPager->journalOff += 4;
}
IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
pPager->journalOff, szPg));
PAGER_INCR(sqlite3_pager_writej_count);
pPager->journalOff += szPg;
PAGERTRACE5("JOURNAL %d page %d needSync=%d hash(%08x)\n",
PAGERID(pPager), pPg->pgno, pPg->needSync, pager_pagehash(pPg));
*(u32*)pEnd = saved;
/* An error has occured writing to the journal file. The
** transaction will be rolled back by the layer above.
@@ -4068,9 +4077,11 @@ static int pager_write(PgHdr *pPg){
page_add_to_stmt_list(pPg);
}else{
i64 offset = pPager->stmtNRec*(4+pPager->pageSize);
char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7)-4;
put32bits(pData2, pPg->pgno);
rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize+4, offset);
char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
rc = write32bits(pPager->stfd, offset, pPg->pgno);
if( rc==SQLITE_OK ){
rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize, offset+4);
}
PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
if( rc!=SQLITE_OK ){
return rc;