From 8220da7b8b1a9450607ea78266cd78110a318970 Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Mon, 5 Jul 2010 17:43:32 +0000
Subject: [PATCH] When rolling back page 1 from a journal, restore the
 "nReserve" setting in case it has been corrupted by a prior crash.

FossilOrigin-Name: c0d124da88e84e68679c2f3f4b2b35c03aecc916
---
 manifest      | 24 +++++++++++++++++-------
 manifest.uuid |  2 +-
 src/pager.c   | 50 +++++++++++++++++++++++++-------------------------
 3 files changed, 43 insertions(+), 33 deletions(-)

diff --git a/manifest b/manifest
index 2b8bfa0e95..4a70add3a2 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,8 @@
-C Do\snot\sreport\san\serror\sif\sthe\sopen-file-count\sis\snot\sas\sit\sshould\sbe\safter\srunning\sa\smulti-threaded\stest.\sThe\scounter\sinstrumentation\sis\snot\sthread-safe.
-D 2010-07-05T14:54:49
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA1
+
+C When\srolling\sback\spage\s1\sfrom\sa\sjournal,\srestore\sthe\s"nReserve"\ssetting\nin\scase\sit\shas\sbeen\scorrupted\sby\sa\sprior\scrash.
+D 2010-07-05T17:43:32
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -156,7 +159,7 @@ F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f
 F src/os_os2.c 665876d5eec7585226b0a1cf5e18098de2b2da19
 F src/os_unix.c c6112f0ae34f23ae5ca0189a685e084befbdcf26
 F src/os_win.c 883caa09d8cf7c4dfdef6eba6930466cb8a8275c
-F src/pager.c e4470e43f0fefe5f81034efb706a2b1f4db5ca41
+F src/pager.c 14ec8ea3d27cf4c8b7b6a6139c150b50dd28df3e
 F src/pager.h 879fdde5a102d2f21a3135d6f647530b21c2796c
 F src/parse.y ace5c7a125d9f2a410e431ee3209034105045f7e
 F src/pcache.c 1e9aa2dbc0845b52e1b51cc39753b6d1e041cb07
@@ -830,7 +833,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 684eae6623ef1d0336b7a734b17ed307c720b6f4
-R 63f603eae54aff0b7014e11adb19abba
-U dan
-Z c2e1163608ea0fe576a6717534083382
+P ea80b21c881fabaec1da788588c35c6c9782dcbd
+R 5de919a3a55f2a8c35bbb58047acd345
+U drh
+Z aa2a677064258d9e6322a258f0100e48
+-----BEGIN PGP SIGNATURE-----
+Version: GnuPG v1.4.6 (GNU/Linux)
+
+iD8DBQFMMhnIoxKgR168RlERAv13AJ0RezR75fN7II4WYQ+k2k88YWRNwgCeOLx/
+tAjj2vuEc4/BCzTdXBrdXV8=
+=hcXV
+-----END PGP SIGNATURE-----
diff --git a/manifest.uuid b/manifest.uuid
index 2574592c50..04aaee85d4 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ea80b21c881fabaec1da788588c35c6c9782dcbd
\ No newline at end of file
+c0d124da88e84e68679c2f3f4b2b35c03aecc916
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index a7d8565de1..038a87fd76 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -1517,6 +1517,21 @@ static u32 pager_cksum(Pager *pPager, const u8 *aData){
   return cksum;
 }
 
+/*
+** Report the current page size and number of reserved bytes back
+** to the codec.
+*/
+#ifdef SQLITE_HAS_CODEC
+static void pagerReportSize(Pager *pPager){
+  if( pPager->xCodecSizeChng ){
+    pPager->xCodecSizeChng(pPager->pCodec, pPager->pageSize,
+                           (int)pPager->nReserve);
+  }
+}
+#else
+# define pagerReportSize(X)     /* No-op if we do not support a codec */
+#endif
+
 /*
 ** Read a single page from either the journal file (if isMainJrnl==1) or
 ** from the sub-journal (if isMainJrnl==0) and playback that page.
@@ -1609,12 +1624,21 @@ static int pager_playback_one_page(
     }
   }
 
+  /* If this page has already been played by before during the current
+  ** rollback, then don't bother to play it back again.
+  */
   if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
     return rc;
   }
-
   assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );
 
+  /* When playing back page 1, restore the nReserve setting
+  */
+  if( pgno==1 && pPager->nReserve!=((u8*)aData)[20] ){
+    pPager->nReserve = ((u8*)aData)[20];
+    pagerReportSize(pPager);
+  }
+
   /* If the pager is in RESERVED state, then there must be a copy of this
   ** page in the pager cache. In this case just update the pager cache,
   ** not the database file. The page is left marked dirty in this case.
@@ -2751,21 +2775,6 @@ void sqlite3PagerSetBusyhandler(
   pPager->pBusyHandlerArg = pBusyHandlerArg;
 }
 
-/*
-** Report the current page size and number of reserved bytes back
-** to the codec.
-*/
-#ifdef SQLITE_HAS_CODEC
-static void pagerReportSize(Pager *pPager){
-  if( pPager->xCodecSizeChng ){
-    pPager->xCodecSizeChng(pPager->pCodec, pPager->pageSize,
-                           (int)pPager->nReserve);
-  }
-}
-#else
-# define pagerReportSize(X)     /* No-op if we do not support a codec */
-#endif
-
 /*
 ** Change the page size used by the Pager object. The new page size 
 ** is passed in *pPageSize.
@@ -2905,15 +2914,6 @@ int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
   ** to WAL mode yet.
   */
   assert( !pagerUseWal(pPager) );
-#if 0
-  if( pagerUseWal(pPager) ){
-    int isInWal = 0;
-    rc = sqlite3WalRead(pPager->pWal, 1, &isInWal, N, pDest);
-    if( rc!=SQLITE_OK || isInWal ){
-      return rc;
-    }
-  }
-#endif
 
   if( isOpen(pPager->fd) ){
     IOTRACE(("DBHDR %p 0 %d\n", pPager, N))