-C Replace\sthe\satoi()\slibrary\sroutine\swith\sa\sfaster\shome-grown\sversion\sin\sthe\nVDBE.\s\sThis\sgives\sa\sdramatic\sspeed\simprovement\sfor\ssome\skinds\sof\squeries.\s(CVS\s784)
-D 2002-11-11T00:05:43
+C Back\sout\sthe\schanges\sin\sthe\spager\sthat\ssorted\spages\sprior\sto\swriting\sthem\nto\sthe\sdatabase.\s\sAdditional\smeasurements\sshowed\sno\sperformance\sgains.\s(CVS\s785)
+D 2002-11-11T01:04:48
F Makefile.in d6c9a85c2a5e696843201d090dcf8bf2f8716f2a
F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
F src/md5.c fe4f9c9c6f71dfc26af8da63e4d04489b1430565
F src/os.c caf5a34b35a2d99a58457517261c879ac29b0a05
F src/os.h 1caaea972d1c0401cfe6300aba51fb0f6fe435c9
-F src/pager.c 27d9b94641e968bafabfd2119d9ba4304ccb69a4
+F src/pager.c 691571c468e36212677ed0b1db475dba4dba46bf
F src/pager.h 6991c9c2dc5e4c7f2df4d4ba47d1c6458f763a32
F src/parse.y 469c9636ff713e63c00234662209f11668671ae9
F src/printf.c 5c50fc1da75c8f5bf432b1ad17d91d6653acd167
F www/sqlite.tcl ae3dcfb077e53833b59d4fcc94d8a12c50a44098
F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
-P a6ef6657a4377684dc2fce7be2bbf009fd2d2f37
-R 185b0bc33f10b4a768e6cfb7280605c4
+P 263a8ca40f7ff66fbdcb43bf9032391d5b1e68bd
+R 0010d81229c7872c45b3b325790678da
U drh
-Z f3f9009eb197efb6353cb5684648e29d
+Z a3b8e3b4a8a73490705deeac8230e339
** file simultaneously, or one process from reading the database while
** another is writing.
**
-** @(#) $Id: pager.c,v 1.57 2002/11/10 23:32:57 drh Exp $
+** @(#) $Id: pager.c,v 1.58 2002/11/11 01:04:48 drh Exp $
*/
#include "os.h" /* Must be first to enable large file support */
#include "sqliteInt.h"
PgHdr *pNextFree, *pPrevFree; /* Freelist of pages where nRef==0 */
PgHdr *pNextAll, *pPrevAll; /* A list of all pages */
PgHdr *pNextCkpt, *pPrevCkpt; /* List of pages in the checkpoint journal */
- PgHdr *pSort; /* Next in list of pages to be written */
u8 inJournal; /* TRUE if has been written to journal */
u8 inCkpt; /* TRUE if written to the checkpoint journal */
u8 dirty; /* TRUE if we need to write back changes */
return SQLITE_OK;
}
-/*
-** The parameters are pointers to the head of two sorted lists
-** of page headers. Merge these two lists together and return
-** a single sorted list. This routine forms the core of the
-** merge-sort algorithm that sorts dirty pages into accending
-** order prior to writing them back to the disk.
-**
-** In the case of a tie, left sorts in front of right.
-**
-** Headers are sorted in order of ascending page number.
-*/
-static PgHdr *page_merge(PgHdr *pLeft, PgHdr *pRight){
- PgHdr sHead;
- PgHdr *pTail;
- pTail = &sHead;
- pTail->pSort = 0;
- while( pLeft && pRight ){
- if( pLeft->pgno<=pRight->pgno ){
- pTail->pSort = pLeft;
- pLeft = pLeft->pSort;
- }else{
- pTail->pSort = pRight;
- pRight = pRight->pSort;
- }
- pTail = pTail->pSort;
- }
- if( pLeft ){
- pTail->pSort = pLeft;
- }else if( pRight ){
- pTail->pSort = pRight;
- }
- return sHead.pSort;
-}
-
-
/*
** Sync the journal and then write all free dirty pages to the database
** file.
** If we are writing to temporary database, there is no need to preserve
** the integrity of the journal file, so we can save time and skip the
** fsync().
-**
-** This routine goes to the extra trouble of sorting all the dirty
-** pages by their page number prior to writing them. Tests show that
-** writing pages in order by page number gives a modest speed improvement
-** under Linux.
*/
static int syncAllPages(Pager *pPager){
PgHdr *pPg;
- PgHdr *pToWrite;
-# define NSORT 28
Pgno lastPgno;
- int i;
- PgHdr *apSorter[NSORT];
int rc = SQLITE_OK;
/* Sync the journal before modifying the main database
pPager->needSync = 0;
}
- /* Create a list of all dirty pages
+ /* Write all dirty free pages to the disk in the order that they
+ ** appear on the disk. We have experimented with sorting the pages
+ ** by page numbers so that they are written in order, but that does
+ ** not appear to improve performance.
*/
- pToWrite = 0;
for(pPg=pPager->pFirst; pPg; pPg=pPg->pNextFree){
if( pPg->dirty ){
- pPg->pSort = pToWrite;
- pToWrite = pPg;
- }
- }
-
- /* Sort the list of dirty pages into accending order by
- ** page number
- */
- for(i=0; i<NSORT; i++){
- apSorter[i] = 0;
- }
- while( pToWrite ){
- pPg = pToWrite;
- pToWrite = pPg->pSort;
- pPg->pSort = 0;
- for(i=0; i<NSORT-1; i++){
- if( apSorter[i]==0 ){
- apSorter[i] = pPg;
- break;
- }else{
- pPg = page_merge(apSorter[i], pPg);
- apSorter[i] = 0;
+ if( lastPgno==0 || pPg->pgno!=lastPgno+1 ){
+ sqliteOsSeek(&pPager->fd, (pPg->pgno-1)*SQLITE_PAGE_SIZE);
}
+ rc = sqliteOsWrite(&pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);
+ if( rc!=SQLITE_OK ) break;
+ pPg->dirty = 0;
+ lastPgno = pPg->pgno;
}
- if( i>=NSORT-1 ){
- apSorter[NSORT-1] = page_merge(apSorter[NSORT-1],pPg);
- }
- }
- pToWrite = 0;
- for(i=0; i<NSORT; i++){
- pToWrite = page_merge(apSorter[i], pToWrite);
- }
-
- /* Write all dirty pages back to the database and mark
- ** them all clean.
- */
- lastPgno = 0;
- for(pPg=pToWrite; pPg; pPg=pPg->pSort){
- if( lastPgno==0 || pPg->pgno!=lastPgno-1 ){
- sqliteOsSeek(&pPager->fd, (pPg->pgno-1)*SQLITE_PAGE_SIZE);
- }
- rc = sqliteOsWrite(&pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);
- if( rc!=SQLITE_OK ) break;
- pPg->dirty = 0;
- lastPgno = pPg->pgno;
}
return rc;
}
projects / thirdparty / sqlite.git / commitdiff
