diff --git a/manifest b/manifest
index 910fb3ee23..640bbce8d5 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Make\ssure\sthe\squeueMutex\sis\sheld\sprior\sto\swriting\sthe\spQueueLast\sfield\nof\sthe\swrite\squeue\sin\sthe\sasync\sdemonstration\scode.\s\sTicket\s#3405.\s(CVS\s5744)
-D 2008-09-26T20:02:50
+C Add\sthe\s"truncate"\sjournal\smode\swhich\scommits\stransactions\sby\struncating\sthe\nrollback\sjournal\sfile\sto\szero\slength\sand\snot\scalling\sfsync().\s(CVS\s5745)
+D 2008-09-26T21:08:08
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in e4ab842f9a64ef61d57093539a8aab76b12810db
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -137,12 +137,12 @@ F src/os_common.h 24525d8b7bce66c374dfc1810a6c9043f3359b60
 F src/os_os2.c e391fc95adc744bbdcefd4d11e3066998185a0a0
 F src/os_unix.c f33b69d8a85372b270fe37ee664a4c2140a5217d
 F src/os_win.c 3209dc0ed734291764393ea8d534ba0d8696a540
-F src/pager.c 7a3ba14e27cf134e54f0f4f58d307de13a7ea28d
-F src/pager.h 1ef5a3f8e0b4c8b30f19c8e01d4fca2db9bb5797
+F src/pager.c 6426902ba983ce6872fcec20ba72796a79d6cead
+F src/pager.h 30e71f447ecbcfef707bb72cc813ce37ab5a2bc9
 F src/parse.y d0f76d2cb8d6883d5600dc20beb961a6022b94b8
 F src/pcache.c 52108517c38bcf023f3977085a66aacb520a5385
 F src/pcache.h 0b6871e820159629915e8688b5c67a81a203773f
-F src/pragma.c e633b6b7dabc110e2abfed4e35ba34a4039cb65c
+F src/pragma.c 0b1c2d2a241dd79a7361bbeb8ff575a9e9d7cd71
 F src/prepare.c c7e00ed1b0bdcf699b1aad651247d4dc3d281b0b
 F src/printf.c 785f87120589c1db672e37c6eb1087c456e6f84d
 F src/random.c 11bbdf7def3746a762fbdb56c9d04648135ad6d8
@@ -390,7 +390,7 @@ F test/join3.test 6f0c774ff1ba0489e6c88a3e77b9d3528fb4fda0
 F test/join4.test 1a352e4e267114444c29266ce79e941af5885916
 F test/join5.test 86675fc2919269aa923c84dd00ee4249b97990fe
 F test/journal1.test 36f2d1bb9bf03f790f43fbdb439e44c0657fab19
-F test/jrnlmode.test 1ab9729d6bbb6fb355cbb4bb41f1f0c271fc251a
+F test/jrnlmode.test 54469696db41e185a37aed3b3848998cca4e0c37
 F test/lastinsert.test 474d519c68cb79d07ecae56a763aa7f322c72f51
 F test/laststmtchanges.test 18ead86c8a87ade949a1d5658f6dc4bb111d1b02
 F test/like.test fef924922828d5a2a5bff80b9bdd9ff57a1ca500
@@ -453,7 +453,7 @@ F test/pageropt.test 3ee6578891baaca967f0bd349e4abfa736229e1a
 F test/pagesize.test 0d9ff3fedfce6e5ffe8fa7aca9b6d3433a2e843b
 F test/pcache.test 515b4c26e9f57660357dfff5b6b697acac1abc5f
 F test/pcache2.test 2b4fa1bee5cfc338d8c04eb6ed7eaf41f478bf7c
-F test/permutations.test 41832b86c152c140bcdf75a35a7c82badd8912b9
+F test/permutations.test 9f9ee1a8899cc26c7f850c92bfc7efc85bb71161
 F test/pragma.test c86359a8e0b28abdcc0ff4936f7966c446d0479a
 F test/pragma2.test 5364893491b9231dd170e3459bfc2e2342658b47
 F test/printf.test 262a5acd3158f788e9bdf7f18d718f3af32ff6ef
@@ -637,7 +637,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 1dbced29de5f59ba2ebf877edcadf171540374d1
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 28fd0a50ca8529892f5b1ababd38d494889eed6d
-R 42f79e8d6bad8dc05f28b70884a1cf00
+P 5622a1e285fc4d5720f7180a0eb551952f2df331
+R d784c96d098146eb0a9f2a9c5180ad72
 U drh
-Z c1f39a8806852672a67f740f0e33cd9d
+Z ac8d7bb3e53159a4cf0d1bb60149a10e
diff --git a/manifest.uuid b/manifest.uuid
index 1f441bd728..705249497a 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5622a1e285fc4d5720f7180a0eb551952f2df331
\ No newline at end of file
+7c561f2e9264de676c1028943f6c3d06542fd802
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 5f05c5399f..5011418447 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.494 2008/09/23 16:41:30 danielk1977 Exp $
+** @(#) $Id: pager.c,v 1.495 2008/09/26 21:08:08 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -971,7 +971,11 @@ static int pager_end_transaction(Pager *pPager, int hasMaster){
     pPager->stmtOpen = 0;
   }
   if( pPager->journalOpen ){
-    if( pPager->exclusiveMode 
+    if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE
+         && (rc = sqlite3OsTruncate(pPager->jfd, 0))==SQLITE_OK ){
+      pPager->journalOff = 0;
+      pPager->journalStarted = 0;
+    }else if( pPager->exclusiveMode 
      || pPager->journalMode==PAGER_JOURNALMODE_PERSIST
     ){
       rc = zeroJournalHdr(pPager, hasMaster);
@@ -979,6 +983,7 @@ static int pager_end_transaction(Pager *pPager, int hasMaster){
       pPager->journalOff = 0;
       pPager->journalStarted = 0;
     }else{
+      assert( pPager->journalMode==PAGER_JOURNALMODE_DELETE || rc );
       sqlite3OsClose(pPager->jfd);
       pPager->journalOpen = 0;
       if( rc==SQLITE_OK && !pPager->tempFile ){
@@ -4207,24 +4212,31 @@ int sqlite3PagerLockingMode(Pager *pPager, int eMode){
 }
 
 /*
-** Get/set the journal-mode for this pager. Parameter eMode must be one
-** of PAGER_JOURNALMODE_QUERY, PAGER_JOURNALMODE_DELETE or 
-** PAGER_JOURNALMODE_PERSIST. If the parameter is not _QUERY, then
-** the journal-mode is set to the value specified.
+** Get/set the journal-mode for this pager. Parameter eMode must be one of:
 **
-** The returned value is either PAGER_JOURNALMODE_DELETE or
-** PAGER_JOURNALMODE_PERSIST, indicating the current (possibly updated)
+**    PAGER_JOURNALMODE_QUERY
+**    PAGER_JOURNALMODE_DELETE
+**    PAGER_JOURNALMODE_TRUNCATE
+**    PAGER_JOURNALMODE_PERSIST
+**    PAGER_JOURNALMODE_OFF
+**
+** If the parameter is not _QUERY, then the journal-mode is set to the
+** value specified.
+**
+** The returned indicate the current (possibly updated)
 ** journal-mode.
 */
 int sqlite3PagerJournalMode(Pager *pPager, int eMode){
   assert( eMode==PAGER_JOURNALMODE_QUERY
             || eMode==PAGER_JOURNALMODE_DELETE
+            || eMode==PAGER_JOURNALMODE_TRUNCATE
             || eMode==PAGER_JOURNALMODE_PERSIST
             || eMode==PAGER_JOURNALMODE_OFF );
   assert( PAGER_JOURNALMODE_QUERY<0 );
-  assert( PAGER_JOURNALMODE_DELETE>=0 && PAGER_JOURNALMODE_PERSIST>=0 );
   if( eMode>=0 ){
     pPager->journalMode = eMode;
+  }else{
+    assert( eMode==PAGER_JOURNALMODE_QUERY );
   }
   return (int)pPager->journalMode;
 }
diff --git a/src/pager.h b/src/pager.h
index 906c92eabc..41332d0201 100644
--- a/src/pager.h
+++ b/src/pager.h
@@ -13,7 +13,7 @@
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
 **
-** @(#) $Id: pager.h,v 1.83 2008/09/18 17:34:44 danielk1977 Exp $
+** @(#) $Id: pager.h,v 1.84 2008/09/26 21:08:08 drh Exp $
 */
 
 #ifndef _PAGER_H_
@@ -65,6 +65,7 @@ typedef struct PgHdr DbPage;
 #define PAGER_JOURNALMODE_DELETE      0   /* Commit by deleting journal file */
 #define PAGER_JOURNALMODE_PERSIST     1   /* Commit by zeroing journal header */
 #define PAGER_JOURNALMODE_OFF         2   /* Journal omitted.  */
+#define PAGER_JOURNALMODE_TRUNCATE    3   /* Commit by truncating journal */
 
 /*
 ** See source code comments for a detailed description of the following
diff --git a/src/pragma.c b/src/pragma.c
index e227a1d4d7..442a89d51e 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code used to implement the PRAGMA command.
 **
-** $Id: pragma.c,v 1.187 2008/09/16 14:38:03 danielk1977 Exp $
+** $Id: pragma.c,v 1.188 2008/09/26 21:08:08 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -449,13 +449,13 @@ void sqlite3Pragma(
   */
   if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
     int eMode;
-    static char * const azModeName[] = {"delete", "persist", "off"};
+    static char * const azModeName[] = {"delete", "persist", "off", "truncate"};
 
     if( zRight==0 ){
       eMode = PAGER_JOURNALMODE_QUERY;
     }else{
       int n = strlen(zRight);
-      eMode = 2;
+      eMode = sizeof(azModeName)/sizeof(azModeName[0]) - 1;
       while( eMode>=0 && sqlite3StrNICmp(zRight, azModeName[eMode], n)!=0 ){
         eMode--;
       }
@@ -491,6 +491,7 @@ void sqlite3Pragma(
       eMode = sqlite3PagerJournalMode(pPager, eMode);
     }
     assert( eMode==PAGER_JOURNALMODE_DELETE
+              || eMode==PAGER_JOURNALMODE_TRUNCATE
               || eMode==PAGER_JOURNALMODE_PERSIST
               || eMode==PAGER_JOURNALMODE_OFF );
     sqlite3VdbeSetNumCols(v, 1);
diff --git a/test/jrnlmode.test b/test/jrnlmode.test
index 75773dd8e6..6383299883 100644
--- a/test/jrnlmode.test
+++ b/test/jrnlmode.test
@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library. The focus
 # of these tests is the journal mode pragma.
 #
-# $Id: jrnlmode.test,v 1.5 2008/08/02 20:09:37 drh Exp $
+# $Id: jrnlmode.test,v 1.6 2008/09/26 21:08:08 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -67,6 +67,18 @@ do_test jrnlmode-1.7 {
     PRAGMA temp.journal_mode;
   } 
 } {delete delete delete}
+do_test jrnlmode-1.7.1 {
+  execsql {
+    PRAGMA journal_mode = truncate;
+  } 
+} {truncate}
+do_test jrnlmode-1.7.2 {
+  execsql {
+    PRAGMA journal_mode;
+    PRAGMA main.journal_mode;
+    PRAGMA temp.journal_mode;
+  } 
+} {truncate truncate truncate}
 do_test jrnlmode-1.8 {
   execsql {
     PRAGMA journal_mode = off;
@@ -76,7 +88,7 @@ do_test jrnlmode-1.8 {
 ifcapable attach {
   do_test jrnlmode-1.9 {
     execsql {
-      PRAGMA journal_mode = persist;
+      PRAGMA journal_mode = PERSIST;
       ATTACH ':memory:' as aux1;
     }
     execsql {
@@ -86,7 +98,7 @@ ifcapable attach {
   } {persist persist}
   do_test jrnlmode-1.10 {
     execsql {
-      PRAGMA main.journal_mode = off;
+      PRAGMA main.journal_mode = OFF;
     }
     execsql {
       PRAGMA main.journal_mode;
@@ -111,7 +123,7 @@ ifcapable attach {
   } {off persist persist}
   do_test jrnlmode-1.11 {
     execsql {
-      PRAGMA aux1.journal_mode = delete;
+      PRAGMA aux1.journal_mode = DELETE;
     }
     execsql {
       PRAGMA main.journal_mode;
@@ -142,6 +154,18 @@ ifcapable attach {
       PRAGMA aux3.journal_mode;
     }
   } {delete delete delete delete delete}
+  do_test jrnlmode-1.14 {
+    execsql {
+      PRAGMA journal_mode = TRUNCATE;
+    }
+    execsql {
+      PRAGMA main.journal_mode;
+      PRAGMA temp.journal_mode;
+      PRAGMA aux1.journal_mode;
+      PRAGMA aux2.journal_mode;
+      PRAGMA aux3.journal_mode;
+    }
+  } {truncate truncate truncate truncate truncate}
   
   do_test jrnlmode-1.99 {
     execsql {
diff --git a/test/permutations.test b/test/permutations.test
index acdb662b68..4bd9d73493 100644
--- a/test/permutations.test
+++ b/test/permutations.test
@@ -9,7 +9,7 @@
 #
 #***********************************************************************
 #
-# $Id: permutations.test,v 1.30 2008/09/12 10:22:40 danielk1977 Exp $
+# $Id: permutations.test,v 1.31 2008/09/26 21:08:08 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -377,10 +377,23 @@ run_tests "exclusive" -description {
 } -presql {
   pragma locking_mode = 'exclusive'
 } -include {
+  vacuum.test
   rollback.test select1.test select2.test 
   malloc.test ioerr.test
 } 
 
+# Run some tests in exclusive locking mode with truncated journals.
+#
+run_tests "exclusive-truncate" -description {
+  Run tests in exclusive locking mode and truncate journal mode.
+} -presql {
+  pragma locking_mode = 'exclusive';
+  pragma journal_mode = TRUNCATE;
+} -include {
+  delete.test delete2.test insert.test rollback.test select1.test
+  select2.test update.test malloc.test ioerr.test
+} 
+
 # Run some tests in persistent journal mode.
 #
 run_tests "persistent_journal" -description {
@@ -392,6 +405,18 @@ run_tests "persistent_journal" -description {
   select2.test trans.test update.test vacuum.test 
 }
 
+# Run some tests in truncating journal mode.
+#
+run_tests "truncate_journal" -description {
+  Run tests in persistent-journal mode.
+} -presql {
+  pragma journal_mode = truncate
+} -include {
+  delete.test delete2.test insert.test rollback.test select1.test
+  select2.test trans.test update.test vacuum.test 
+  malloc.test ioerr.test
+}
+
 # Run some error tests in persistent journal mode.
 #
 run_tests "persistent_journal_error" -description {