diff --git a/manifest b/manifest
index a3027053de..9329dc5547 100644
--- a/manifest
+++ b/manifest
@@ -1,8 +1,8 @@
 -----BEGIN PGP SIGNED MESSAGE-----
 Hash: SHA1
 
-C Further\ssimplifications\sto\sthe\sSHM\slocking\slogic.\s\sRemove\sthe\sSQLITE_SHM_QUERY\noption.\s\sUnify\sthe\sWRITE\sto\sREAD\sand\sRECOVER\sto\sREAD\stransitions.
-D 2010-05-05T19:09:49
+C Change\sthe\sbehavior\sof\sthe\ssqlite3_wal_hook()\scallback.\s\sIt\sshould\snow\sreturn\nSQLITE_OK\sor\san\serror\scode\sand\sthe\serror\scode\sis\spropagated\sback\sup\sthe\s\nstack.\s\sIf\sa\scheckpoint\sis\sdesired,\sthe\scallback\sshould\sinvoke\nsqlite3_wal_callback()\sitself.
+D 2010-05-05T20:00:26
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in d83a0ffef3dcbfb08b410a6c6dd6c009ec9167fb
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -134,7 +134,7 @@ F src/journal.c b0ea6b70b532961118ab70301c00a33089f9315c
 F src/legacy.c a199d7683d60cef73089e892409113e69c23a99f
 F src/lempar.c 7f026423f4d71d989e719a743f98a1cbd4e6d99e
 F src/loadext.c 1c7a61ce1281041f437333f366a96aa0d29bb581
-F src/main.c 23c51a3c67da0c1cceab38f3575fff2f2ae49464
+F src/main.c cc62a14dd4a4e4f95ea21e762c87da14fe72e63c
 F src/malloc.c a08f16d134f0bfab6b20c3cd142ebf3e58235a6a
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c 89d4ea8d5cdd55635cbaa48ad53132af6294cbb2
@@ -169,13 +169,13 @@ F src/resolve.c ac5f1a713cd1ae77f08b83cc69581e11bf5ae6f9
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c c03d8a0565febcde8c6a12c5d77d065fddae889b
 F src/shell.c c40427c7245535a04a9cb4a417b6cc05c022e6a4
-F src/sqlite.h.in e6ead287be496055ade50424b7799f84475da7d7
+F src/sqlite.h.in c68d5a6c13c04812b2873bb93d2132d1f5d3ccf8
 F src/sqlite3ext.h 69dfb8116af51b84a029cddb3b35062354270c89
 F src/sqliteInt.h 9819b45610abeca390176243a9a31758c1f0ac7a
 F src/sqliteLimit.h 196e2f83c3b444c4548fc1874f52f84fdbda40f3
 F src/status.c 4df6fe7dce2d256130b905847c6c60055882bdbe
 F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
-F src/tclsqlite.c a6d69438c21e89c26dc791bfa4c5ba6da9dbb515
+F src/tclsqlite.c 6bc5fbde634b9cb42b3d29d674fa6cd0c22c0881
 F src/test1.c ff95ca772d1df51618f9f1ef7ea432cdf851f97b
 F src/test2.c 31f1b9d076b4774a22d2605d0af1f34e14a9a7bd
 F src/test3.c 4c21700c73a890a47fc685c1097bfb661346ac94
@@ -219,7 +219,7 @@ F src/vacuum.c 90a32e098cf06c5524c76b21027ee7520a821065
 F src/vdbe.c 8be37a1b18786b5c026adcb2e9edc93e3a940885
 F src/vdbe.h 471f6a3dcec4817ca33596fe7f6654d56c0e75f3
 F src/vdbeInt.h 19ebc8c2a2e938340051ee65af3f377fb99102d1
-F src/vdbeapi.c f2da22e5dcb1943ce6605614636e6bf32158640d
+F src/vdbeapi.c dc3138f10afbc95ed3c21dd25abb154504b1db9d
 F src/vdbeaux.c 395d21a1617553ea9b9f4abe0d302449d8549e1d
 F src/vdbeblob.c 5327132a42a91e8b7acfb60b9d2c3b1c5c863e0e
 F src/vdbemem.c 2a82f455f6ca6f78b59fb312f96054c04ae0ead1
@@ -766,10 +766,10 @@ F test/wal.test f0b331017a12a31dd4bbb20aee9c179fbfdd5921
 F test/walbak.test a0e45187c7d8928df035dfea29b99b016b21ca3c
 F test/walcrash.test f6d5fb2bb108876f04848720a488065d9deef69f
 F test/walfault.test 9146e22807d6c75885614f623f5c8b1272c8488e
-F test/walhook.test 5f18e0fc8787f1f8889d7a9971af18f334f83786
+F test/walhook.test a1c375ae791d5d7d511c166159729230791c574d
 F test/walmode.test bac6f06544a8554588a1543def996bbe2fc41792
 F test/walslow.test d21625e2e99e11c032ce949e8a94661576548933
-F test/walthread.test 08f553f38b99ad0fb96d188c175808df9dc5f790
+F test/walthread.test 1a8c55cd9e3272ba0caa028d8f0ead04989a3378
 F test/where.test de337a3fe0a459ec7c93db16a519657a90552330
 F test/where2.test 43d4becaf5a5df854e6c21d624a1cb84c6904554
 F test/where3.test aa44a9b29e8c9f3d7bb94a3bb3a95b31627d520d
@@ -813,14 +813,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 72663123d6be2b194cad7a6057d0f20dd0d9fe05
-R a9b4a745dd84e1e6c5aa687e7866b305
+P e9bfa6e4ce7d1edc6be8b9173ac3b6bfd180632a
+R e9fe5c9efad10446aa83b71914d33765
 U drh
-Z ba8b9550144dbde8add352394fc13a1f
+Z b26c7b5452be96cecc1a35cb38e6299b
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.6 (GNU/Linux)
 
-iD8DBQFL4cJ/oxKgR168RlERAn5HAJ9H9/xHH78dGiXt8tKDpcuSc8tO9QCfaUiX
-yaPexQIPM4/rd4uKeZ+hs2w=
-=FoJP
+iD8DBQFL4c5doxKgR168RlERAuadAJ9ImhZl3Q6JfaSg2/LCnbmOP58sywCfTv4N
+Ru+croJcME10MvNF9/ygcGg=
+=+Gfk
 -----END PGP SIGNATURE-----
diff --git a/manifest.uuid b/manifest.uuid
index 464cbe9114..d7480930ec 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-e9bfa6e4ce7d1edc6be8b9173ac3b6bfd180632a
\ No newline at end of file
+1b14195e05fe5551992a39246ec3bcf6a33bbfac
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 962c857d67..4cd90663f7 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1189,19 +1189,20 @@ void *sqlite3_rollback_hook(
 #ifndef SQLITE_OMIT_WAL
 /*
 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
-** Return non-zero, indicating to the caller that a checkpoint should be run,
-** if the number of frames in the log file is greater than 
-** sqlite3.pWalArg cast to an integer (the value configured by
+** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
+** is greater than sqlite3.pWalArg cast to an integer (the value configured by
 ** wal_autocheckpoint()).
 */ 
 int sqlite3WalDefaultHook(
-  void *p,               /* Argument */
+  void *pClientData,     /* Argument */
   sqlite3 *db,           /* Connection */
-  const char *zNotUsed,  /* Database */
+  const char *zDb,       /* Database */
   int nFrame             /* Size of WAL */
 ){
-  UNUSED_PARAMETER(zNotUsed);
-  return ( nFrame>=SQLITE_PTR_TO_INT(p));
+  if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
+    sqlite3_wal_checkpoint(db, zDb);
+  }
+  return SQLITE_OK;
 }
 #endif /* SQLITE_OMIT_WAL */
 
@@ -1218,13 +1219,11 @@ int sqlite3WalDefaultHook(
 */
 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
 #ifndef SQLITE_OMIT_WAL
-  sqlite3_mutex_enter(db->mutex);
   if( nFrame>0 ){
     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
   }else{
     sqlite3_wal_hook(db, 0, 0);
   }
-  sqlite3_mutex_leave(db->mutex);
 #endif
   return SQLITE_OK;
 }
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 2672690b75..e59b02c74b 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -5780,9 +5780,10 @@ void sqlite3_log(int iErrCode, const char *zFormat, ...);
 ** is the number of pages currently in the log file, including those that
 ** were just committed.
 **
-** If an invocation of the callback function returns non-zero, then a
-** checkpoint is automatically run on the database. If zero is returned,
-** no special action is taken.
+** The callback function should normally return SQLITE_OK.  If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to fail.
 **
 ** A single database handle may have at most a single log callback 
 ** registered at one time. Calling [sqlite3_wal_hook()] replaces any
diff --git a/src/tclsqlite.c b/src/tclsqlite.c
index d9d6a7d8ae..d8d0fd2b96 100644
--- a/src/tclsqlite.c
+++ b/src/tclsqlite.c
@@ -123,7 +123,7 @@ struct SqliteDb {
   SqlFunc *pFunc;            /* List of SQL functions */
   Tcl_Obj *pUpdateHook;      /* Update hook script (if any) */
   Tcl_Obj *pRollbackHook;    /* Rollback hook script (if any) */
-  Tcl_Obj *pLogHook;         /* WAL hook script (if any) */
+  Tcl_Obj *pWalHook;         /* WAL hook script (if any) */
   Tcl_Obj *pUnlockNotify;    /* Unlock notify script (if any) */
   SqlCollate *pCollate;      /* List of SQL collation functions */
   int rc;                    /* Return code of most recent sqlite3_exec() */
@@ -486,8 +486,8 @@ static void DbDeleteCmd(void *db){
   if( pDb->pRollbackHook ){
     Tcl_DecrRefCount(pDb->pRollbackHook);
   }
-  if( pDb->pLogHook ){
-    Tcl_DecrRefCount(pDb->pLogHook);
+  if( pDb->pWalHook ){
+    Tcl_DecrRefCount(pDb->pWalHook);
   }
   if( pDb->pCollateNeeded ){
     Tcl_DecrRefCount(pDb->pCollateNeeded);
@@ -593,19 +593,22 @@ static void DbRollbackHandler(void *clientData){
   }
 }
 
-static int DbLogHandler(
+/*
+** This procedure handles wal_hook callbacks.
+*/
+static int DbWalHandler(
   void *clientData, 
   sqlite3 *db, 
   const char *zDb, 
   int nEntry
 ){
-  int ret = 0;
+  int ret = SQLITE_OK;
   Tcl_Obj *p;
   SqliteDb *pDb = (SqliteDb*)clientData;
   Tcl_Interp *interp = pDb->interp;
-  assert(pDb->pLogHook);
+  assert(pDb->pWalHook);
 
-  p = Tcl_DuplicateObj(pDb->pLogHook);
+  p = Tcl_DuplicateObj(pDb->pWalHook);
   Tcl_IncrRefCount(p);
   Tcl_ListObjAppendElement(interp, p, Tcl_NewStringObj(zDb, -1));
   Tcl_ListObjAppendElement(interp, p, Tcl_NewIntObj(nEntry));
@@ -2775,7 +2778,7 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
     if( choice==DB_UPDATE_HOOK ){
       ppHook = &pDb->pUpdateHook;
     }else if( choice==DB_WAL_HOOK ){
-      ppHook = &pDb->pLogHook;
+      ppHook = &pDb->pWalHook;
     }else{
       ppHook = &pDb->pRollbackHook;
     }
@@ -2801,7 +2804,7 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
 
     sqlite3_update_hook(pDb->db, (pDb->pUpdateHook?DbUpdateHandler:0), pDb);
     sqlite3_rollback_hook(pDb->db,(pDb->pRollbackHook?DbRollbackHandler:0),pDb);
-    sqlite3_wal_hook(pDb->db,(pDb->pLogHook?DbLogHandler:0),pDb);
+    sqlite3_wal_hook(pDb->db,(pDb->pWalHook?DbWalHandler:0),pDb);
 
     break;
   }
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index 2a8c1dd18f..2f5aaa36d1 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -318,10 +318,8 @@ static int doWalCallbacks(sqlite3 *db){
     Btree *pBt = db->aDb[i].pBt;
     if( pBt ){
       int nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
-      if( db->xWalCallback && nEntry>0 && rc==SQLITE_OK
-       && db->xWalCallback(db->pWalArg, db, db->aDb[i].zName, nEntry)
-      ){
-        rc = sqlite3Checkpoint(db, i);
+      if( db->xWalCallback && nEntry>0 && rc==SQLITE_OK ){
+        rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zName, nEntry);
       }
     }
   }
diff --git a/test/walhook.test b/test/walhook.test
index 05f543d2c8..e0f6dc2e7f 100644
--- a/test/walhook.test
+++ b/test/walhook.test
@@ -49,7 +49,7 @@ do_test walhook-1.2 {
   set ::wal_hook
 } {main 5}
 do_test walhook-1.3 {
-  proc wal_hook {args} { return 1 }
+  proc wal_hook {args} { db eval {PRAGMA wal_checkpoint}; return 0 }
   execsql { INSERT INTO t1 VALUES(2, 'two') }
   file size test.db
 } [expr 3*1024]
diff --git a/test/walthread.test b/test/walthread.test
index 620f8f220f..13b1b4b35c 100644
--- a/test/walthread.test
+++ b/test/walthread.test
@@ -390,7 +390,7 @@ do_thread_test walthread-3 -seconds $seconds(walthread-3) -init {
   set nextwrite $E(pid)
 
   proc wal_hook {zDb nEntry} {
-    if {$nEntry>10} { return 1 }
+    if {$nEntry>10} {db eval {PRAGMA wal_checkpoint}}
     return 0
   }
   db wal_hook wal_hook
@@ -443,7 +443,7 @@ do_thread_test2 walthread-4 -seconds $seconds(walthread-4) -init {
 } -thread w 1 {
 
   proc wal_hook {zDb nEntry} {
-    if {$nEntry>15} { return 1 }
+    if {$nEntry>15} {db eval {PRAGMA wal_checkpoint}}
     return 0
   }
   db wal_hook wal_hook