From: drh <drh@noemail.net>
Date: Sat, 15 Jan 2011 18:11:12 +0000 (+0000)
Subject: Fix the change-counter increment for WAL pages so that it works even when
X-Git-Tag: version-3.7.5~33^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=54a7347aa1d25d87f3c4774c8a350912f4d76379;p=thirdparty%2Fsqlite.git

Fix the change-counter increment for WAL pages so that it works even when
invoked from xStress.  Ticket [5d863f876ee9561b95e2].

FossilOrigin-Name: 228e7c34c64114670fe015747d47fdaa3b7e1270
---

diff --git a/manifest b/manifest
index 86cf2f03fd..2944df000f 100644
--- a/manifest
+++ b/manifest
@@ -1,8 +1,8 @@
 -----BEGIN PGP SIGNED MESSAGE-----
 Hash: SHA1
 
-C Increment\sthe\schange\scounter\sand\supdate\sthe\sSQLite\sversion\snumber\swhenever\npage\s1\sis\sadded\sto\sthe\sWAL.\s\sTicket\s[5d863f876ee9561b9]
-D 2011-01-15T17:12:59.482
+C Fix\sthe\schange-counter\sincrement\sfor\sWAL\spages\sso\sthat\sit\sworks\seven\swhen\ninvoked\sfrom\sxStress.\s\sTicket\s[5d863f876ee9561b95e2].
+D 2011-01-15T18:11:12.573
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in de6498556d536ae60bb8bb10e8c1ba011448658c
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -165,7 +165,7 @@ F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f
 F src/os_os2.c 72d0b2e562952a2464308c4ce5f7913ac10bef3e
 F src/os_unix.c aeaf65d261219ad96c021cfd0672509d83c005e4
 F src/os_win.c 2f90f7bdec714fad51cd31b4ecad3cc1b4bb5aad
-F src/pager.c 737025a2e7457ae7cfd4fe1f0cc69f69d88b29b4
+F src/pager.c 3e3e5cd39724107dc98edb39c1528b2d250c7b9a
 F src/pager.h 0ea59db2a33bc6c2c02cae34de33367e1effdf76
 F src/parse.y 12b7ebd61ea54f0e1b1083ff69cc2c8ce9353d58
 F src/pcache.c 09d38c44ab275db581f7a2f6ff8b9bc7f8c0faaa
@@ -899,14 +899,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P af54963f0fa0afafbc2d0847f30543c041b182ec
-R 2e070d9bb52da592e341dbace3cf5d95
+P c1e0d09cd3f5feae123468a35f147021d839641c
+R f10af8d4a2b23d5e0a4042a0305ee5bd
 U drh
-Z 2f025605b789f039118b3a16146dfc2d
+Z e0ffffbf7b453d6eb6ed50379cb7cd3c
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.6 (GNU/Linux)
 
-iD8DBQFNMdWfoxKgR168RlERAmfoAJ9Y78wB/3baCsxKX+NyeGTMQLqGDACeOyQw
-/EmrRAxlTmynxXA/PJ4j5Yo=
-=dp+d
+iD8DBQFNMeNDoxKgR168RlERAhpGAJ4lGMlKMGe3/3RAk9NL9lmCoMpu8wCfey5w
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+=rI++
 -----END PGP SIGNATURE-----
diff --git a/manifest.uuid b/manifest.uuid
index e4f2521d70..6c440bf13d 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c1e0d09cd3f5feae123468a35f147021d839641c
\ No newline at end of file
+228e7c34c64114670fe015747d47fdaa3b7e1270
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 297ac99596..e0b4cd3c50 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -2915,8 +2915,28 @@ static int pagerRollbackWal(Pager *pPager){
   return rc;
 }
 
-/* Forward declaration */
-static int pager_incr_changecounter(Pager*,int);
+
+/*
+** Update the value of the change-counter at offsets 24 and 92 in
+** the header and the sqlite version number at offset 96.
+**
+** This is an unconditional update.  See also the pager_incr_changecounter()
+** routine which only updates the change-counter if the update is actually
+** needed, as determined by the pPager->changeCountDone state variable.
+*/
+static void pager_write_changecounter(PgHdr *pPg){
+  u32 change_counter;
+
+  /* Increment the value just read and write it back to byte 24. */
+  change_counter = sqlite3Get4byte((u8*)pPg->pPager->dbFileVers)+1;
+  put32bits(((char*)pPg->pData)+24, change_counter);
+
+  /* Also store the SQLite version number in bytes 96..99 and in
+  ** bytes 92..95 store the change counter for which the version number
+  ** is valid. */
+  put32bits(((char*)pPg->pData)+92, change_counter);
+  put32bits(((char*)pPg->pData)+96, SQLITE_VERSION_NUMBER);
+}
 
 /*
 ** This function is a wrapper around sqlite3WalFrames(). As well as logging
@@ -2947,11 +2967,7 @@ static int pagerWalFrames(
   }
 #endif
 
-  if( pList->pgno==1 ){
-    pPager->changeCountDone = 0;
-    pager_incr_changecounter(pPager,0);
-    pPager->changeCountDone = 0;
-  }
+  if( pList->pgno==1 ) pager_write_changecounter(pList);
   rc = sqlite3WalFrames(pPager->pWal, 
       pPager->pageSize, pList, nTruncate, isCommit, syncFlags
   );
@@ -5509,7 +5525,13 @@ void sqlite3PagerDontWrite(PgHdr *pPg){
 /*
 ** This routine is called to increment the value of the database file 
 ** change-counter, stored as a 4-byte big-endian integer starting at 
-** byte offset 24 of the pager file.
+** byte offset 24 of the pager file.  The secondary change counter at
+** 92 is also updated, as is the SQLite version number at offset 96.
+**
+** But this only happens if the pPager->changeCountDone flag is false.
+** To avoid excess churning of page 1, the update only happens once.
+** See also the pager_write_changecounter() routine that does an 
+** unconditional update of the change counters.
 **
 ** If the isDirectMode flag is zero, then this is done by calling 
 ** sqlite3PagerWrite() on page 1, then modifying the contents of the
@@ -5550,7 +5572,6 @@ static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
 
   if( !pPager->changeCountDone && pPager->dbSize>0 ){
     PgHdr *pPgHdr;                /* Reference to page 1 */
-    u32 change_counter;           /* Initial value of change-counter field */
 
     assert( !pPager->tempFile && isOpen(pPager->fd) );
 
@@ -5568,16 +5589,8 @@ static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
     }
 
     if( rc==SQLITE_OK ){
-      /* Increment the value just read and write it back to byte 24. */
-      change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
-      change_counter++;
-      put32bits(((char*)pPgHdr->pData)+24, change_counter);
-
-      /* Also store the SQLite version number in bytes 96..99 and in
-      ** bytes 92..95 store the change counter for which the version number
-      ** is valid. */
-      put32bits(((char*)pPgHdr->pData)+92, change_counter);
-      put32bits(((char*)pPgHdr->pData)+96, SQLITE_VERSION_NUMBER);
+      /* Actually do the update of the change counter */
+      pager_write_changecounter(pPgHdr);
 
       /* If running in direct mode, write the contents of page 1 to the file. */
       if( DIRECT_MODE ){