diff --git a/manifest b/manifest
index ac6831495f..cd07a4add4 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Always\sset\sBtShared.db\swhen\sentering\sthe\sBtShared\smutex.\sTicket\s#3793.\s(CVS\s6480)
-D 2009-04-10T09:47:07
+C Changes\sto\sensure\sthat\swhen\srunning\sin\sshared-cache\smode\swith\sa\snon-threadsafe\sbuild,\sthe\scorrect\sbusy-handler\scallback\sis\salways\sinvoked.\s(CVS\s6481)
+D 2009-04-10T12:55:17
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -102,9 +102,9 @@ F src/attach.c af80fa85d391ad302c148c4e2524a2cebec64cb2
 F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
 F src/backup.c 0082d0e5a63f04e88faee0dff0a7d63d3e92a78d
 F src/bitvec.c ef370407e03440b0852d05024fb016b14a471d3d
-F src/btmutex.c 527b63e275d132564710dec47ddab52a0f2d7f4e
+F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
 F src/btree.c 8331febf3769cdac2e0cde463be4ed901406b783
-F src/btree.h 8007018c1753944790c39610280894ab280210b8
+F src/btree.h 99fcc7e8c4a1e35afe271bcb38de1a698dfc904e
 F src/btreeInt.h df64030d632f8c8ac217ed52e8b6b3eacacb33a5
 F src/build.c 2882f22078db1c3f887b1aca77ff460cf9461c62
 F src/callback.c 73016376d6848ba987709e8c9048d4f0e0776036
@@ -200,11 +200,11 @@ F src/update.c 8ededddcde6f7b6da981dd0429a5d34518a475b7
 F src/utf.c 9541d28f40441812c0b40f00334372a0542c00ff
 F src/util.c 469d74f5bf09ed6398702c7da2ef8a34e979a1c1
 F src/vacuum.c 07121a727beeee88f27d704a00313ad6a7c9bef0
-F src/vdbe.c 146b72ae0783281b39049593c422a9a1527e82d3
+F src/vdbe.c 88bc70921ccdcff8bfdf574f3e2285d17ab97103
 F src/vdbe.h 35a648bc3279a120da24f34d9a25213ec15daf8a
-F src/vdbeInt.h 53a2f4696871712646c77351904576cca6ad9752
+F src/vdbeInt.h df5c5a1c739c98af2c83440dde3fc361240f3a25
 F src/vdbeapi.c d3c6f28dbf462187f3fd696f2357e0d23940abac
-F src/vdbeaux.c e1aa4cd6f4972f2420e38e195df4297349f109aa
+F src/vdbeaux.c b48b0af5acd527ffe31a6da4f61971f7bd0bec0b
 F src/vdbeblob.c e67757450ae8581a8b354d9d7e467e41502dfe38
 F src/vdbemem.c 9798905787baae83d0b53b62030e32ecf7a0586f
 F src/vtab.c f1aba5a6dc1f83b97a39fbbc58ff8cbc76311347
@@ -717,7 +717,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 2cc68272b1f70701268075cfa82fa64bb2a8179d
-R 0f5ed1cbc4ec520cfd83afb78d3917f3
+P ed6620ba589ddbb6ca86f42a7652e3b019195647
+R 59f76bf89532711f903241145d0b77ea
 U danielk1977
-Z 46ae6a8835e1cba4786ac026de3d9fbb
+Z ac75d7099ed4abde9c5f40681fcfbea3
diff --git a/manifest.uuid b/manifest.uuid
index 154252be0e..d4126113f8 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ed6620ba589ddbb6ca86f42a7652e3b019195647
\ No newline at end of file
+683e4bd74783e6e3f6cf75f9582008c7b7e02a01
\ No newline at end of file
diff --git a/src/btmutex.c b/src/btmutex.c
index 06cbed8d9c..34399bb1fc 100644
--- a/src/btmutex.c
+++ b/src/btmutex.c
@@ -10,7 +10,7 @@
 **
 *************************************************************************
 **
-** $Id: btmutex.c,v 1.14 2009/04/10 09:47:07 danielk1977 Exp $
+** $Id: btmutex.c,v 1.15 2009/04/10 12:55:17 danielk1977 Exp $
 **
 ** This file contains code used to implement mutexes on Btree objects.
 ** This code really belongs in btree.c.  But btree.c is getting too
@@ -18,7 +18,8 @@
 ** a good breakout.
 */
 #include "btreeInt.h"
-#if SQLITE_THREADSAFE && !defined(SQLITE_OMIT_SHARED_CACHE)
+#ifndef SQLITE_OMIT_SHARED_CACHE
+#if SQLITE_THREADSAFE
 
 /*
 ** Obtain the BtShared mutex associated with B-Tree handle p. Also,
@@ -336,5 +337,18 @@ void sqlite3BtreeMutexArrayLeave(BtreeMutexArray *pArray){
   }
 }
 
-
-#endif  /* SQLITE_THREADSAFE && !SQLITE_OMIT_SHARED_CACHE */
+#else
+void sqlite3BtreeEnter(Btree *p){
+  p->pBt->db = p->db;
+}
+void sqlite3BtreeEnterAll(sqlite3 *db){
+  int i;
+  for(i=0; i<db->nDb; i++){
+    Btree *p = db->aDb[i].pBt;
+    if( p ){
+      p->pBt->db = p->db;
+    }
+  }
+}
+#endif /* if SQLITE_THREADSAFE */
+#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */
diff --git a/src/btree.h b/src/btree.h
index c12bee8b53..378c9892cb 100644
--- a/src/btree.h
+++ b/src/btree.h
@@ -13,7 +13,7 @@
 ** subsystem.  See comments in the source code for a detailed description
 ** of what each interface routine does.
 **
-** @(#) $Id: btree.h,v 1.112 2009/04/02 20:16:59 drh Exp $
+** @(#) $Id: btree.h,v 1.113 2009/04/10 12:55:17 danielk1977 Exp $
 */
 #ifndef _BTREE_H_
 #define _BTREE_H_
@@ -186,42 +186,39 @@ void sqlite3BtreeCursorList(Btree*);
 ** use mutexes to access the BtShared structures.  So make the
 ** Enter and Leave procedures no-ops.
 */
-#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+#ifndef SQLITE_OMIT_SHARED_CACHE
   void sqlite3BtreeEnter(Btree*);
-  void sqlite3BtreeLeave(Btree*);
-#ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
-  int sqlite3BtreeHoldsMutex(Btree*);
+  void sqlite3BtreeEnterAll(sqlite3*);
+#else
+# define sqlite3BtreeEnter(X) 
+# define sqlite3BtreeEnterAll(X)
 #endif
+
+#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
+  void sqlite3BtreeLeave(Btree*);
   void sqlite3BtreeEnterCursor(BtCursor*);
   void sqlite3BtreeLeaveCursor(BtCursor*);
-  void sqlite3BtreeEnterAll(sqlite3*);
   void sqlite3BtreeLeaveAll(sqlite3*);
-#ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
-  int sqlite3BtreeHoldsAllMutexes(sqlite3*);
-#endif
   void sqlite3BtreeMutexArrayEnter(BtreeMutexArray*);
   void sqlite3BtreeMutexArrayLeave(BtreeMutexArray*);
   void sqlite3BtreeMutexArrayInsert(BtreeMutexArray*, Btree*);
-#else
-# define sqlite3BtreeEnter(X)
-# define sqlite3BtreeLeave(X)
 #ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
-# define sqlite3BtreeHoldsMutex(X) 1
+  /* These routines are used inside assert() statements only. */
+  int sqlite3BtreeHoldsMutex(Btree*);
+  int sqlite3BtreeHoldsAllMutexes(sqlite3*);
 #endif
+#else
+
+# define sqlite3BtreeLeave(X)
 # define sqlite3BtreeEnterCursor(X)
 # define sqlite3BtreeLeaveCursor(X)
-# define sqlite3BtreeEnterAll(X)
 # define sqlite3BtreeLeaveAll(X)
-#ifndef NDEBUG
-  /* This routine is used inside assert() statements only. */
-# define sqlite3BtreeHoldsAllMutexes(X) 1
-#endif
 # define sqlite3BtreeMutexArrayEnter(X)
 # define sqlite3BtreeMutexArrayLeave(X)
 # define sqlite3BtreeMutexArrayInsert(X,Y)
+
+# define sqlite3BtreeHoldsMutex(X) 1
+# define sqlite3BtreeHoldsAllMutexes(X) 1
 #endif
 
 
diff --git a/src/vdbe.c b/src/vdbe.c
index 7ef177a77b..eee932a8a0 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.831 2009/04/10 00:56:29 drh Exp $
+** $Id: vdbe.c,v 1.832 2009/04/10 12:55:17 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
@@ -568,7 +568,7 @@ int sqlite3VdbeExec(
 
   assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
   assert( db->magic==SQLITE_MAGIC_BUSY );
-  sqlite3BtreeMutexArrayEnter(&p->aMutex);
+  sqlite3VdbeMutexArrayEnter(p);
   if( p->rc==SQLITE_NOMEM ){
     /* This happens if a malloc() inside a call to sqlite3_column_text() or
     ** sqlite3_column_text16() failed.  */
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index c564d98afa..d9becb180c 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -15,7 +15,7 @@
 ** 6000 lines long) it was split up into several smaller files and
 ** this header information was factored out.
 **
-** $Id: vdbeInt.h,v 1.166 2009/03/18 10:33:02 danielk1977 Exp $
+** $Id: vdbeInt.h,v 1.167 2009/04/10 12:55:17 danielk1977 Exp $
 */
 #ifndef _VDBEINT_H_
 #define _VDBEINT_H_
@@ -379,6 +379,12 @@ int sqlite3VdbeCloseStatement(Vdbe *, int);
 int sqlite3VdbeReleaseBuffers(Vdbe *p);
 #endif
 
+#ifndef SQLITE_OMIT_SHARED_CACHE
+void sqlite3VdbeMutexArrayEnter(Vdbe *p);
+#else
+# define sqlite3VdbeMutexArrayEnter(p)
+#endif
+
 int sqlite3VdbeMemTranslate(Mem*, u8);
 #ifdef SQLITE_DEBUG
   void sqlite3VdbePrintSql(Vdbe*);
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 61c0702f78..1b741a0a46 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -14,7 +14,7 @@
 ** to version 2.8.7, all this code was combined into the vdbe.c source file.
 ** But that file was getting too big so this subroutines were split out.
 **
-** $Id: vdbeaux.c,v 1.449 2009/04/10 00:56:29 drh Exp $
+** $Id: vdbeaux.c,v 1.450 2009/04/10 12:55:17 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "vdbeInt.h"
@@ -1610,6 +1610,33 @@ int sqlite3VdbeCloseStatement(Vdbe *p, int eOp){
   return rc;
 }
 
+/*
+** If SQLite is compiled to support shared-cache mode and to be threadsafe,
+** this routine obtains the mutex associated with each BtShared structure
+** that may be accessed by the VM passed as an argument. In doing so it
+** sets the BtShared.db member of each of the BtShared structures, ensuring
+** that the correct busy-handler callback is invoked if required.
+**
+** If SQLite is not threadsafe but does support shared-cache mode, then
+** sqlite3BtreeEnterAll() is invoked to set the BtShared.db variables
+** of all of BtShared structures accessible via the database handle 
+** associated with the VM. Of course only a subset of these structures
+** will be accessed by the VM, and we could use Vdbe.btreeMask to figure
+** that subset out, but there is no advantage to doing so.
+**
+** If SQLite is not threadsafe and does not support shared-cache mode, this
+** function is a no-op.
+*/
+#ifndef SQLITE_OMIT_SHARED_CACHE
+void sqlite3VdbeMutexArrayEnter(Vdbe *p){
+#if SQLITE_THREADSAFE
+  sqlite3BtreeMutexArrayEnter(&p->aMutex);
+#else
+  sqlite3BtreeEnterAll(p->db);
+#endif
+}
+#endif
+
 /*
 ** This routine is called the when a VDBE tries to halt.  If the VDBE
 ** has made changes and is in autocommit mode, then commit those
@@ -1659,7 +1686,7 @@ int sqlite3VdbeHalt(Vdbe *p){
     int isSpecialError;            /* Set to true if a 'special' error */
 
     /* Lock all btrees used by the statement */
-    sqlite3BtreeMutexArrayEnter(&p->aMutex);
+    sqlite3VdbeMutexArrayEnter(p);
 
     /* Check for one of the special errors */
     mrc = p->rc & 0xff;