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Eliminate some unnecessary IO during a commit in full auto-vacuum mode. (CVS 5426)

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FossilOrigin-Name: 1d01c02ab04f9cc0eb6a2a46a24d3ea63a617d5b
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danielk1977
2008-07-16 18:17:55 +00:00
parent 01859b0b07
commit 4c99999965
5 changed files with 38 additions and 23 deletions
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24
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 1.465 2008/07/11 03:34:10 drh Exp $
** @(#) $Id: pager.c,v 1.466 2008/07/16 18:17:56 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -5184,8 +5184,13 @@ void sqlite3PagerSetCodec(
** required that a statement transaction was not active, but this restriction
** has been removed (CREATE INDEX needs to move a page when a statement
** transaction is active).
**
** If the fourth argument, isCommit, is non-zero, then this page is being
** moved as part of a database reorganization just before the transaction
** is being committed. In this case, it is guaranteed that the database page
** pPg refers to will not be written to again within this transaction.
*/
int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
PgHdr *pPgOld; /* The page being overwritten. */
int h;
Pgno needSyncPgno = 0;
@@ -5198,7 +5203,15 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
pager_get_content(pPg);
if( pPg->needSync ){
/* If the journal needs to be sync()ed before page pPg->pgno can
** be written to, store pPg->pgno in local variable needSyncPgno.
**
** If the isCommit flag is set, there is no need to remember that
** the journal needs to be sync()ed before database page pPg->pgno
** can be written to. The caller has already promised not to write to it.
*/
if( pPg->needSync && !isCommit ){
needSyncPgno = pPg->pgno;
assert( pPg->inJournal || (int)pgno>pPager->origDbSize );
assert( pPg->dirty );
@@ -5245,8 +5258,9 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
/* If needSyncPgno is non-zero, then the journal file needs to be
** sync()ed before any data is written to database file page needSyncPgno.
** Currently, no such page exists in the page-cache and the
** Pager.pInJournal bit has been set. This needs to be remedied by loading
** the page into the pager-cache and setting the PgHdr.needSync flag.
** "is journaled" bitvec flag has been set. This needs to be remedied by
** loading the page into the pager-cache and setting the PgHdr.needSync
** flag.
**
** If the attempt to load the page into the page-cache fails, (due
** to a malloc() or IO failure), clear the bit in the pInJournal[]