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

FossilOrigin-Name: 1d01c02ab04f9cc0eb6a2a46a24d3ea63a617d5b

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\stest\sin\sfunc.test\sso\sthat\sit\sworks\son\smachines\sthat\slack\slong\sdouble.\s(CVS\s5425)
-D 2008-07-16T18:04:37
+C Eliminate\ssome\sunnecessary\sIO\sduring\sa\scommit\sin\sfull\sauto-vacuum\smode.\s(CVS\s5426)
+D 2008-07-16T18:17:56
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in a03f7cb4f7ad50bc53a788c6c544430e81f95de4
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -96,7 +96,7 @@ F src/attach.c b18ba42c77f7d3941f5d23d2ca20fa1d841a4e91
 F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
 F src/bitvec.c 95c86bd18d8fedf0533f5af196192546e10a7e7d
 F src/btmutex.c 709cad2cdca0afd013f0f612363810e53f59ec53
-F src/btree.c cda41ffc78e53cd29e53eab47d174d3e6afd680d
+F src/btree.c 5dcc47a35d12bc8584d7c89ed113d24fb9fbc2ca
 F src/btree.h 03256ed7ee42b5ecacbe887070b0f8249e7d069d
 F src/btreeInt.h a6a5ffab12fa2c15392b85242cd5568371949046
 F src/build.c bac7233d984be3805aaa41cf500f7ee12dc97249
@@ -134,8 +134,8 @@ F src/os_common.h 24525d8b7bce66c374dfc1810a6c9043f3359b60
 F src/os_os2.c b16aee2f727842f758140641835a46caad322f5d
 F src/os_unix.c 1df6108efdb7957a9f28b9700600e58647c9c12d
 F src/os_win.c 2bf2f8cd700299564cc236262c2668e1e02c626a
-F src/pager.c bb286b2fc0c7c87d0a8cbfee96a3e953da1e53dd
-F src/pager.h 6aa3050a3c684475a5a9dbad5ff1cebad612acba
+F src/pager.c e65d78bdbd316c3ca0135d2a98ecc607873145aa
+F src/pager.h 588c1ac195228b2da45c4e5f7ab6c2fd253d1751
 F src/parse.y 097bff733e89fbf554a07d9327046718ce364011
 F src/pragma.c 6fad83fbcc7ec6e76d91fe2805fe972ff3af6a0c
 F src/prepare.c c9bb0aacb7a571d049805699ed18f2bb136ea091
@@ -608,7 +608,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 1dbced29de5f59ba2ebf877edcadf171540374d1
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 1841aee6045b00cf4ab7b8485f5ab537d5fcd272
-R 8f639165d0cabfcde66742c2739c4326
-U drh
-Z f1ce4c404d5037a5b2007a246716de72
+P 8686959d4289dc0bf9e1c353b948f26cca5a9a65
+R b11ed1a66c5f2d78327ee14b0dec1dcc
+U danielk1977
+Z b90aebe08a66c9ca365a4e0a71d2b848

manifest.uuid

@@ -1 +1 @@
-8686959d4289dc0bf9e1c353b948f26cca5a9a65
+1d01c02ab04f9cc0eb6a2a46a24d3ea63a617d5b

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.482 2008/07/12 14:52:20 drh Exp $
+** $Id: btree.c,v 1.483 2008/07/16 18:17:56 danielk1977 Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -2112,7 +2112,8 @@ static int relocatePage(
   MemPage *pDbPage,        /* Open page to move */
   u8 eType,                /* Pointer map 'type' entry for pDbPage */
   Pgno iPtrPage,           /* Pointer map 'page-no' entry for pDbPage */
-  Pgno iFreePage           /* The location to move pDbPage to */
+  Pgno iFreePage,          /* The location to move pDbPage to */
+  int isCommit
 ){
   MemPage *pPtrPage;   /* The page that contains a pointer to pDbPage */
   Pgno iDbPage = pDbPage->pgno;
@@ -2127,7 +2128,7 @@ static int relocatePage(
   /* Move page iDbPage from its current location to page number iFreePage */
   TRACE(("AUTOVACUUM: Moving %d to free page %d (ptr page %d type %d)\n", 
       iDbPage, iFreePage, iPtrPage, eType));
-  rc = sqlite3PagerMovepage(pPager, pDbPage->pDbPage, iFreePage);
+  rc = sqlite3PagerMovepage(pPager, pDbPage->pDbPage, iFreePage, isCommit);
   if( rc!=SQLITE_OK ){
     return rc;
   }
@@ -2277,7 +2278,7 @@ static int incrVacuumStep(BtShared *pBt, Pgno nFin){
       
       rc = sqlite3PagerWrite(pLastPg->pDbPage);
       if( rc==SQLITE_OK ){
-        rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg);
+        rc = relocatePage(pBt, pLastPg, eType, iPtrPage, iFreePg, nFin!=0);
       }
       releasePage(pLastPg);
       if( rc!=SQLITE_OK ){
@@ -6030,7 +6031,7 @@ static int btreeCreateTable(Btree *p, int *piTable, int flags){
         releasePage(pRoot);
         return rc;
       }
-      rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove);
+      rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
       releasePage(pRoot);
 
       /* Obtain the page at pgnoRoot */
@@ -6238,7 +6239,7 @@ static int btreeDropTable(Btree *p, int iTable, int *piMoved){
         if( rc!=SQLITE_OK ){
           return rc;
         }
-        rc = relocatePage(pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable);
+        rc = relocatePage(pBt, pMove, PTRMAP_ROOTPAGE, 0, iTable, 0);
         releasePage(pMove);
         if( rc!=SQLITE_OK ){
           return rc;

src/pager.c

@@ -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[]

src/pager.h

@@ -13,7 +13,7 @@
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
 **
-** @(#) $Id: pager.h,v 1.76 2008/06/07 08:58:22 danielk1977 Exp $
+** @(#) $Id: pager.h,v 1.77 2008/07/16 18:17:56 danielk1977 Exp $
 */
 
 #ifndef _PAGER_H_
@@ -105,7 +105,7 @@ sqlite3_file *sqlite3PagerFile(Pager*);
 const char *sqlite3PagerDirname(Pager*);
 const char *sqlite3PagerJournalname(Pager*);
 int sqlite3PagerNosync(Pager*);
-int sqlite3PagerMovepage(Pager*,DbPage*,Pgno);
+int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int);
 void *sqlite3PagerGetData(DbPage *); 
 void *sqlite3PagerGetExtra(DbPage *); 
 int sqlite3PagerLockingMode(Pager *, int);