diff --git a/manifest b/manifest
index 7ccd8bcfc8..7aa1fa9809 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Make\ssure\sthat\swhen\sa\sCREATE\sINDEX\sfails,\sit\sdoes\snot\sleave\sa\sresidue\sbehind\nthat\scan\scorrupt\sthe\sdatabase.\s\sTicket\s#1115.\s(CVS\s2330)
-D 2005-02-14T20:48:19
+C Check\sthat\sread-only\spages\sare\snot\sbeing\smodified\s(disabled\sby\sdefault).\s(CVS\s2331)
+D 2005-02-15T02:54:15
 F Makefile.in d928187101fa3d78426cf48ca30e39d0fb714e57
 F Makefile.linux-gcc a9e5a0d309fa7c38e7c14d3ecf7690879d3a5457
 F README a01693e454a00cc117967e3f9fdab2d4d52e9bc1
@@ -51,7 +51,7 @@ F src/os_unix.c 68d3d32937eee90fe1f50d500d1a4ee826cbe790
 F src/os_unix.h f3097815e041e82e24d92505e1ff61ba24172d13
 F src/os_win.c bddeae1c3299be0fbe47077dd4e98b786a067f71
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
-F src/pager.c d0c1f41b41d2b56a6fd0e1308a66518872f68ed5
+F src/pager.c 69efe972d6034d8d5603f5b2a768e43e25dad0c0
 F src/pager.h 70d496f372163abb6340f474288c4bb9ea962cf7
 F src/parse.y 450fc9c4d5a737be6fdba6e4b2e3de5800d4d750
 F src/pragma.c 7e65c5545d83909238adf231e2a6eee6eb43e0d5
@@ -271,7 +271,7 @@ F www/tclsqlite.tcl e73f8f8e5f20e8277619433f7970060ab01088fc
 F www/vdbe.tcl 095f106d93875c94b47367384ebc870517431618
 F www/version3.tcl 092a01f5ef430d2c4acc0ae558d74c4bb89638a0
 F www/whentouse.tcl 3e522a06ad41992023c80ca29a048ae2331ca5bd
-P 41d2214b83dd52acdda64a50d0c1ef16009d06d0
-R 9e0bcb38fd98e646a6dce64083f59531
-U drh
-Z b1359ca9d31266c1dc27ad6e9e05dbe4
+P cbed92f397ec13b57771ab8b5be74c0cacf35dfd
+R f5e0bf334bc8ca4771ae6f5140466932
+U danielk1977
+Z 79138fc5bf3ab18977a8db63dd8b495b
diff --git a/manifest.uuid b/manifest.uuid
index 36f4e8f326..d68eba3a8c 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cbed92f397ec13b57771ab8b5be74c0cacf35dfd
\ No newline at end of file
+8514a4feb2a86e93c4251c491d394e861bb65edb
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 53c2b84143..ab6490fb9d 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 1.188 2005/02/06 02:45:42 drh Exp $
+** @(#) $Id: pager.c,v 1.189 2005/02/15 02:54:15 danielk1977 Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -168,6 +168,9 @@ struct PgHdr {
   u8 alwaysRollback;             /* Disable dont_rollback() for this page */
   short int nRef;                /* Number of users of this page */
   PgHdr *pDirty;                 /* Dirty pages sorted by PgHdr.pgno */
+#ifdef SQLITE_CHECK_PAGES
+  u32 pageHash;
+#endif
   /* pPager->psAligned bytes of page data follow this header */
   /* Pager.nExtra bytes of local data follow the page data */
 };
@@ -451,6 +454,36 @@ static int pager_errcode(Pager *pPager){
   return rc;
 }
 
+#ifdef SQLITE_CHECK_PAGES
+/*
+** Return a 32-bit hash of the page data for pPage.
+*/
+static u32 pager_pagehash(PgHdr *pPage){
+  u32 hash = 0;
+  int i;
+  unsigned char *pData = (unsigned char *)PGHDR_TO_DATA(pPage);
+  for(i=0; i<pPage->pPager->pageSize; i++){
+    hash = (hash+i)^pData[i];
+  }
+  return hash;
+}
+
+/*
+** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
+** is defined, and NDEBUG is not defined, an assert() statement checks
+** that the page is either dirty or still matches the calculated page-hash.
+*/
+#define CHECK_PAGE(x) checkPage(x)
+static void checkPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  assert( !pPg->pageHash || pPager->errMask || MEMDB || pPg->dirty || 
+      pPg->pageHash==pager_pagehash(pPg) );
+}
+
+#else
+#define CHECK_PAGE(x)
+#endif
+
 /*
 ** When this is called the journal file for pager pPager must be open.
 ** The master journal file name is read from the end of the file and 
@@ -841,6 +874,9 @@ static int pager_unwritelock(Pager *pPager){
       pPg->inJournal = 0;
       pPg->dirty = 0;
       pPg->needSync = 0;
+#ifdef SQLITE_CHECK_PAGES
+      pPg->pageHash = pager_pagehash(pPg);
+#endif
     }
     pPager->dirtyCache = 0;
     pPager->nRec = 0;
@@ -958,6 +994,9 @@ static int pager_playback_one_page(Pager *pPager, OsFile *jfd, int useCksum){
     if( pPager->state>=PAGER_EXCLUSIVE ){
       pPg->dirty = 0;
       pPg->needSync = 0;
+#ifdef SQLITE_CHECK_PAGES
+      pPg->pageHash = pager_pagehash(pPg);
+#endif
     }
     CODEC(pPager, pData, pPg->pgno, 3);
   }
@@ -1086,6 +1125,9 @@ static int pager_reload_cache(Pager *pPager){
     }
     pPg->needSync = 0;
     pPg->dirty = 0;
+#ifdef SQLITE_CHECK_PAGES
+    pPg->pageHash = pager_pagehash(pPg);
+#endif
   }
   return rc;
 }
@@ -2101,6 +2143,9 @@ static int pager_write_pagelist(PgHdr *pList){
 #endif
     if( rc ) return rc;
     pList->dirty = 0;
+#ifdef SQLITE_CHECK_PAGES
+    pList->pageHash = pager_pagehash(pList);
+#endif
     pList = pList->pDirty;
   }
   return SQLITE_OK;
@@ -2388,6 +2433,9 @@ int sqlite3pager_get(Pager *pPager, Pgno pgno, void **ppPage){
         pPager->nRead++;
       }
     }
+#ifdef SQLITE_CHECK_PAGES
+    pPg->pageHash = pager_pagehash(pPg);
+#endif
   }else{
     /* The requested page is in the page cache. */
     pPager->nHit++;
@@ -2440,6 +2488,8 @@ int sqlite3pager_unref(void *pData){
   pPg->nRef--;
   REFINFO(pPg);
 
+  CHECK_PAGE(pPg);
+
   /* When the number of references to a page reach 0, call the
   ** destructor and add the page to the freelist.
   */
@@ -2628,6 +2678,8 @@ int sqlite3pager_write(void *pData){
 
   assert( !pPager->setMaster );
 
+  CHECK_PAGE(pPg);
+
   /* Mark the page as dirty.  If the page has already been written
   ** to the journal then we can return right away.
   */
@@ -2831,6 +2883,9 @@ void sqlite3pager_dont_write(Pager *pPager, Pgno pgno){
     }else{
       TRACE3("DONT_WRITE page %d of %d\n", pgno, PAGERID(pPager));
       pPg->dirty = 0;
+#ifdef SQLITE_CHECK_PAGES
+      pPg->pageHash = pager_pagehash(pPg);
+#endif
     }
   }
 }