Fix for ticket #19: Do not call sqliteOsSync() if the only changes were

changes to TEMP tables. (CVS 530)

FossilOrigin-Name: 33da20b9c1a8eef16ad7ab5929bb8937c75090f2

manifest

@@ -1,5 +1,5 @@
-C When\sdoing\sa\s".dump"\scommand\sin\sthe\scommand-line\sshell,\smake\ssure\sVIEWs\nare\screated\safter\sTABLEs.\s(CVS\s529)
-D 2002-04-13T23:42:24
+C Fix\sfor\sticket\s#19:\sDo\snot\scall\ssqliteOsSync()\sif\sthe\sonly\schanges\swere\nchanges\sto\sTEMP\stables.\s(CVS\s530)
+D 2002-04-18T01:56:58
 F Makefile.in 50f1b3351df109b5774771350d8c1b8d3640130d
 F Makefile.template 89e373b2dad0321df00400fa968dc14b61a03296
 F README a4c0ba11354ef6ba0776b400d057c59da47a4cc0
@@ -33,7 +33,7 @@ F src/main.c df43fe585d2bfb925c837b6822783c0ee3dd6e1c
 F src/md5.c b2b1a34fce66ceca97f4e0dabc20be8be7933c92
 F src/os.c 5ab8b6b4590d0c1ab8e96c67996c170e4462e0fc
 F src/os.h 4a361fccfbc4e7609b3e1557f604f94c1e96ad10
-F src/pager.c f136f5ba82c896d500a10b6a2e5caea62abf716b
+F src/pager.c ba5740104cc27b342cd43eebfdc44d60f64a3ded
 F src/pager.h 6fddfddd3b73aa8abc081b973886320e3c614f0e
 F src/parse.y 9a8a2311dd95101bb02b3991042e619eea49729a
 F src/printf.c 300a90554345751f26e1fc0c0333b90a66110a1d
@@ -131,7 +131,7 @@ F www/speed.tcl da8afcc1d3ccc5696cfb388a68982bc3d9f7f00f
 F www/sqlite.tcl 8b5884354cb615049aed83039f8dfe1552a44279
 F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
 F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
-P 977abbaebe5433c66516d0376a1c229e45b5ab1f
-R 1d18e0543c9a9e3b6f1f1a88dc469706
+P 7edd13468e24d79939f0fa1e58f3b686422ca826
+R d6ef54d3be3cb5d13a1592b37489d27e
 U drh
-Z c041d10ac3286386a2e3e11a69a41456
+Z aa513408483afd37049a6b0b765b2614

manifest.uuid

@@ -1 +1 @@
-7edd13468e24d79939f0fa1e58f3b686422ca826
+33da20b9c1a8eef16ad7ab5929bb8937c75090f2

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.44 2002/03/06 22:01:36 drh Exp $
+** @(#) $Id: pager.c,v 1.45 2002/04/18 01:56:58 drh Exp $
 */
 #include "sqliteInt.h"
 #include "pager.h"
@@ -120,6 +120,7 @@ struct Pager {
   u8 tempFile;                /* zFilename is a temporary file */
   u8 readOnly;                /* True for a read-only database */
   u8 needSync;                /* True if an fsync() is needed on the journal */
+  u8 dirtyFile;               /* True if database file has changed in any way */
   u8 *aInJournal;             /* One bit for each page in the database file */
   u8 *aInCkpt;                /* One bit for each page in the database */
   PgHdr *pFirst, *pLast;      /* List of free pages */
@@ -444,7 +445,7 @@ end_ckpt_playback:
 */
 void sqlitepager_set_cachesize(Pager *pPager, int mxPage){
   if( mxPage>=0 ){
-    pPager->noSync = 0;
+    pPager->noSync = pPager->tempFile;
   }else{
     pPager->noSync = 1;
     mxPage = -mxPage;
@@ -538,6 +539,7 @@ int sqlitepager_open(
   pPager->tempFile = tempFile;
   pPager->readOnly = readOnly;
   pPager->needSync = 0;
+  pPager->noSync = pPager->tempFile;
   pPager->pFirst = 0;
   pPager->pLast = 0;
   pPager->nExtra = nExtra;
@@ -1036,7 +1038,8 @@ int sqlitepager_begin(void *pData){
       return SQLITE_CANTOPEN;
     }
     pPager->journalOpen = 1;
-    pPager->needSync = !pPager->noSync;
+    pPager->needSync = 0;
+    pPager->dirtyFile = 0;
     pPager->state = SQLITE_WRITELOCK;
     sqlitepager_pagecount(pPager);
     pPager->origDbSize = pPager->dbSize;
@@ -1088,6 +1091,7 @@ int sqlitepager_write(void *pData){
   */
   pPg->dirty = 1;
   if( pPg->inJournal && (pPg->inCkpt || pPager->ckptOpen==0) ){
+    pPager->dirtyFile = 1;
     return SQLITE_OK;
   }
 
@@ -1100,6 +1104,7 @@ int sqlitepager_write(void *pData){
   */
   assert( pPager->state!=SQLITE_UNLOCK );
   rc = sqlitepager_begin(pData);
+  pPager->dirtyFile = 1;
   if( rc!=SQLITE_OK ) return rc;
   assert( pPager->state==SQLITE_WRITELOCK );
   assert( pPager->journalOpen );
@@ -1238,6 +1243,13 @@ int sqlitepager_commit(Pager *pPager){
     return SQLITE_ERROR;
   }
   assert( pPager->journalOpen );
+  if( pPager->dirtyFile==0 ){
+    /* Exit early (without doing the time-consuming sqliteOsSync() calls)
+    ** if there have been no changes to the database file. */
+    rc = pager_unwritelock(pPager);
+    pPager->dbSize = -1;
+    return rc;
+  }
   if( pPager->needSync && sqliteOsSync(&pPager->jfd)!=SQLITE_OK ){
     goto commit_abort;
   }