When locking a database file, check if any backup objects need to be restarted even if the page cache is empty. Ticket #3858. (CVS 6632)

FossilOrigin-Name: 90309008c35494c7a075fe76f7eb96b09a01d01b

manifest

@@ -1,5 +1,5 @@
-C Remove\sdebugging\scomments\sleft\sin\sthe\sprior\scheck-in\sby\smistake.\s(CVS\s6631)
-D 2009-05-12T18:00:38
+C When\slocking\sa\sdatabase\sfile,\scheck\sif\sany\sbackup\sobjects\sneed\sto\sbe\srestarted\seven\sif\sthe\spage\scache\sis\sempty.\sTicket\s#3858.\s(CVS\s6632)
+D 2009-05-13T07:52:06
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -103,7 +103,7 @@ F src/alter.c f0430ee68d8d80711155ddf27876abf218903b03
 F src/analyze.c e239496cfb5394ac8867f1c112905ddab8d01cd9
 F src/attach.c 3b99611f04926fc69c35b1145603fc3ddb0ca967
 F src/auth.c 98db07c2088455797678eb1031f42d4d94d18a71
-F src/backup.c 0082d0e5a63f04e88faee0dff0a7d63d3e92a78d
+F src/backup.c 91aaf9f065b923f33d8739f44f71ab8d9226a8d1
 F src/bitvec.c ef370407e03440b0852d05024fb016b14a471d3d
 F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
 F src/btree.c 7c4b02afea7efb561361f20408414fec68df898c
@@ -146,7 +146,7 @@ F src/os_common.h 8c61457df58f1a4bd5f5adc3e90e01b37bf7afbc
 F src/os_os2.c bed77dc26e3a95ce4a204936b9a1ca6fe612fcc5
 F src/os_unix.c e55d977c516ed880a2f83f0610b019efd9f8bc06
 F src/os_win.c 725c38a524d168ce280446ad8761d731bc516405
-F src/pager.c e7171336ffb0f8adc41e55b63dbb2bc5a616a1ae
+F src/pager.c 8bf62fefc7afefc065d37611ebfd1fe0e1c2eb39
 F src/pager.h 73f481a308a873ccd626d97331c081db3b53e2e5
 F src/parse.y ba2fa210be4b17001e0a16d5e73a8141939b1987
 F src/pcache.c 395f752a13574120bd7513a400ba02a265aaa76d
@@ -237,7 +237,7 @@ F test/autoinc.test ab549b48b389cabd92967b86c379ec8b31fa6c16
 F test/autovacuum.test 25f891bc343a8bf5d9229e2e9ddab9f31a9ab5ec
 F test/autovacuum_ioerr2.test 598b0663074d3673a9c1bc9a16e80971313bafe6
 F test/avtrans.test 1e901d8102706b63534dbd2bdd4d8f16c4082650
-F test/backup.test 5e487ec8dad73e9d249e9bb9ca5346a03b601b07
+F test/backup.test 5753622bd0108ac41d8d082afad999232a970b90
 F test/backup2.test 159419073d9769fdb1780ed7e5b391a046f898d5
 F test/backup_ioerr.test 1f012e692f42c0442ae652443258f70e9f20fa38
 F test/backup_malloc.test 1e063c6d75143d0d6e0ae77971dd690070369387
@@ -729,7 +729,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 6fe3750a30ab432ed476c2ae6b58972187abc624
-R 2cb2b27a2df11b0173b7044701cc4d55
-U drh
-Z 5a7b4a2c6dbff0f1170dfdcac92eec35
+P 8207056036e17b99ab660edd650c5a6de1353299
+R 78f6a76a6227328fac7487e61a37848c
+U danielk1977
+Z 0bcee2bab74917e39d092b4429b3d535

manifest.uuid

@@ -1 +1 @@
-8207056036e17b99ab660edd650c5a6de1353299
+90309008c35494c7a075fe76f7eb96b09a01d01b

src/backup.c

@@ -12,7 +12,7 @@
 ** This file contains the implementation of the sqlite3_backup_XXX() 
 ** API functions and the related features.
 **
-** $Id: backup.c,v 1.13 2009/03/16 13:19:36 danielk1977 Exp $
+** $Id: backup.c,v 1.14 2009/05/13 07:52:06 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "btreeInt.h"
@@ -44,6 +44,7 @@ struct sqlite3_backup {
   Pgno nRemaining;         /* Number of pages left to copy */
   Pgno nPagecount;         /* Total number of pages to copy */
 
+  int isAttached;          /* True once backup has been registered with pager */
   sqlite3_backup *pNext;   /* Next backup associated with source pager */
 };
 
@@ -157,6 +158,7 @@ sqlite3_backup *sqlite3_backup_init(
     p->pDestDb = pDestDb;
     p->pSrcDb = pSrcDb;
     p->iNext = 1;
+    p->isAttached = 0;
 
     if( 0==p->pSrc || 0==p->pDest ){
       /* One (or both) of the named databases did not exist. An error has
@@ -167,18 +169,7 @@ sqlite3_backup *sqlite3_backup_init(
       p = 0;
     }
   }
-
-  /* If everything has gone as planned, attach the backup object to the
-  ** source pager. The source pager calls BackupUpdate() and BackupRestart()
-  ** to notify this module if the source file is modified mid-backup.
-  */
   if( p ){
-    sqlite3_backup **pp;             /* Pointer to head of pagers backup list */
-    sqlite3BtreeEnter(p->pSrc);
-    pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
-    p->pNext = *pp;
-    *pp = p;
-    sqlite3BtreeLeave(p->pSrc);
     p->pSrc->nBackup++;
   }
 
@@ -271,6 +262,19 @@ static int backupTruncateFile(sqlite3_file *pFile, i64 iSize){
   return rc;
 }
 
+/*
+** Register this backup object with the associated source pager for
+** callbacks when pages are changed or the cache invalidated.
+*/
+static void attachBackupObject(sqlite3_backup *p){
+  sqlite3_backup **pp;
+  assert( sqlite3BtreeHoldsMutex(p->pSrc) );
+  pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
+  p->pNext = *pp;
+  *pp = p;
+  p->isAttached = 1;
+}
+
 /*
 ** Copy nPage pages from the source b-tree to the destination.
 */
@@ -340,6 +344,8 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){
       p->nRemaining = nSrcPage+1-p->iNext;
       if( p->iNext>(Pgno)nSrcPage ){
         rc = SQLITE_DONE;
+      }else if( !p->isAttached ){
+        attachBackupObject(p);
       }
     }
   
@@ -472,12 +478,14 @@ int sqlite3_backup_finish(sqlite3_backup *p){
 
   /* Detach this backup from the source pager. */
   if( p->pDestDb ){
+    p->pSrc->nBackup--;
+  }
+  if( p->isAttached ){
     pp = sqlite3PagerBackupPtr(sqlite3BtreePager(p->pSrc));
     while( *pp!=p ){
       pp = &(*pp)->pNext;
     }
     *pp = p->pNext;
-    p->pSrc->nBackup--;
   }
 
   /* If a transaction is still open on the Btree, roll it back. */

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.586 2009/05/06 18:57:10 shane Exp $
+** @(#) $Id: pager.c,v 1.587 2009/05/13 07:52:06 danielk1977 Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -3622,7 +3622,7 @@ static int pagerSharedLock(Pager *pPager){
       );
     }
 
-    if( sqlite3PcachePagecount(pPager->pPCache)>0 ){
+    if( pPager->pBackup || sqlite3PcachePagecount(pPager->pPCache)>0 ){
       /* The shared-lock has just been acquired on the database file
       ** and there are already pages in the cache (from a previous
       ** read or write transaction).  Check to see if the database

test/backup.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing the sqlite3_backup_XXX API.
 #
-# $Id: backup.test,v 1.9 2009/03/16 13:19:36 danielk1977 Exp $
+# $Id: backup.test,v 1.10 2009/05/13 07:52:08 danielk1977 Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -859,5 +859,51 @@ do_test backup-9.2.3 {
 } {SQLITE_OK}
 catch {db2 close}
 
+ifcapable memorymanage {
+  db close
+  file delete -force test.db
+  file delete -force bak.db
+
+  sqlite3 db test.db
+  sqlite3 db2 test.db
+  sqlite3 db3 bak.db
+
+  do_test backup-10.1.1 {
+    execsql {
+      BEGIN;
+      CREATE TABLE t1(a, b);
+      INSERT INTO t1 VALUES(1, randstr(1000,1000));
+      INSERT INTO t1 VALUES(2, randstr(1000,1000));
+      INSERT INTO t1 VALUES(3, randstr(1000,1000));
+      INSERT INTO t1 VALUES(4, randstr(1000,1000));
+      INSERT INTO t1 VALUES(5, randstr(1000,1000));
+      CREATE INDEX i1 ON t1(a, b);
+      COMMIT;
+    }
+  } {}
+  do_test backup-10.1.2 {
+    sqlite3_backup B db3 main db2 main
+    B step 5
+  } {SQLITE_OK}
+  do_test backup-10.1.3 {
+    execsql {
+      UPDATE t1 SET b = randstr(500,500);
+    }
+  } {}
+  sqlite3_release_memory [expr 1024*1024]
+  do_test backup-10.1.3 {
+    B step 50
+  } {SQLITE_DONE}
+  do_test backup-10.1.4 {
+    B finish
+  } {SQLITE_OK}
+  do_test backup-10.1.5 {
+    execsql { PRAGMA integrity_check } db3
+  } {ok}
+
+  db2 close
+  db3 close
+}
+
 finish_test