latest sqlite with fix for WAL-caued corruption

Change-Id: I40056f72e4eecf8cbc39d91933cc604ab0c361c1

4 files changed, 568 insertions, 375 deletions

diff --git a/dist/shell.c b/dist/shell.c
index 8879b36..9c21103 100644
--- a/dist/shell.c
+++ b/dist/shell.c
@@ -24,7 +24,6 @@
 #include "sqlite3.h"
 #include <ctype.h>
 #include <stdarg.h>
-
 // Begin Android Add
 #ifndef NO_ANDROID_FUNCS
 #include <sqlite3_android.h>
diff --git a/dist/sqlite3.c b/dist/sqlite3.c
index 121fc93..bbe4d1e 100644
--- a/dist/sqlite3.c
+++ b/dist/sqlite3.c
@@ -516,6 +516,13 @@ SQLITE_PRIVATE   void sqlite3Coverage(int);
 #endif
 
 /*
+** Return true (non-zero) if the input is a integer that is too large
+** to fit in 32-bits.  This macro is used inside of various testcase()
+** macros to verify that we have tested SQLite for large-file support.
+*/
+#define IS_BIG_INT(X)  (((X)&(i64)0xffffffff)!=0)
+
+/*
 ** The macro unlikely() is a hint that surrounds a boolean
 ** expression that is usually false.  Macro likely() surrounds
 ** a boolean expression that is usually true.  GCC is able to
@@ -642,7 +649,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.7.0"
 #define SQLITE_VERSION_NUMBER 3007000
-#define SQLITE_SOURCE_ID      "2010-06-28 10:15:20 4932f22848b3d15a2b6dc5fa2cd69ce19182e2a4"
+#define SQLITE_SOURCE_ID      "2010-07-07 14:45:41 8eefc287265443ec043bdab629597e79c9d22006"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
@@ -1365,16 +1372,23 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** handled as a fatal error by SQLite, vfs implementations should endeavor
 ** to prevent this by setting mxPathname to a sufficiently large value.
 **
-** The xRandomness(), xSleep(), and xCurrentTime() interfaces
-** are not strictly a part of the filesystem, but they are
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
 ** included in the VFS structure for completeness.
 ** The xRandomness() function attempts to return nBytes bytes
 ** of good-quality randomness into zOut.  The return value is
 ** the actual number of bytes of randomness obtained.
 ** The xSleep() method causes the calling thread to sleep for at
 ** least the number of microseconds given.  The xCurrentTime()
-** method returns a Julian Day Number for the current date and time.
-**
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multipled by 86400000 (the number of milliseconds in 
+** a 24-hour day).  
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or 
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 */
 typedef struct sqlite3_vfs sqlite3_vfs;
 struct sqlite3_vfs {
@@ -1401,7 +1415,6 @@ struct sqlite3_vfs {
   ** The methods above are in version 1 of the sqlite_vfs object
   ** definition.  Those that follow are added in version 2 or later
   */
-  int (*xRename)(sqlite3_vfs*, const char *zOld, const char *zNew, int dirSync);
   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
   /*
   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
@@ -11333,9 +11346,11 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_OMIT_CHECK
   "OMIT_CHECK",
 #endif
-#ifdef SQLITE_OMIT_COMPILEOPTION_DIAGS
-  "OMIT_COMPILEOPTION_DIAGS",
-#endif
+/* // redundant
+** #ifdef SQLITE_OMIT_COMPILEOPTION_DIAGS
+**   "OMIT_COMPILEOPTION_DIAGS",
+** #endif
+*/
 #ifdef SQLITE_OMIT_COMPLETE
   "OMIT_COMPLETE",
 #endif
@@ -11369,9 +11384,6 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_OMIT_GET_TABLE
   "OMIT_GET_TABLE",
 #endif
-#ifdef SQLITE_OMIT_GLOBALRECOVER
-  "OMIT_GLOBALRECOVER",
-#endif
 #ifdef SQLITE_OMIT_INCRBLOB
   "OMIT_INCRBLOB",
 #endif
@@ -11450,6 +11462,9 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_OMIT_VIRTUALTABLE
   "OMIT_VIRTUALTABLE",
 #endif
+#ifdef SQLITE_OMIT_WAL
+  "OMIT_WAL",
+#endif
 #ifdef SQLITE_OMIT_WSD
   "OMIT_WSD",
 #endif
@@ -12801,8 +12816,10 @@ SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
 **     sqlite3OsLock()
 **
 */
-#if defined(SQLITE_TEST) && (SQLITE_OS_WIN==0)
-  #define DO_OS_MALLOC_TEST(x) if (!x || !sqlite3IsMemJournal(x)) {     \
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
+  #define DO_OS_MALLOC_TEST(x)                                       \
+  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) {  \
     void *pTstAlloc = sqlite3Malloc(10);                             \
     if (!pTstAlloc) return SQLITE_IOERR_NOMEM;                       \
     sqlite3_free(pTstAlloc);                                         \
@@ -27490,7 +27507,7 @@ static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
   
   /* transform the db path to a unique cache name */
   dbLen = (int)strlen(dbPath);
-  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
+  for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){
     char c = dbPath[i];
     lPath[i+len] = (c=='/')?'_':c;
   }
@@ -27631,6 +27648,9 @@ SQLITE_API int sqlite3_hostid_num = 0;
 
 #define PROXY_HOSTIDLEN    16  /* conch file host id length */
 
+/* Not always defined in the headers as it ought to be */
+extern int gethostuuid(uuid_t id, const struct timespec *wait);
+
 /* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN 
 ** bytes of writable memory.
 */
@@ -27680,6 +27700,7 @@ static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
   char errmsg[64] = "";
   int fd = -1;
   int rc = -1;
+  UNUSED_PARAMETER(myHostID);
 
   /* create a new path by replace the trailing '-conch' with '-break' */
   pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
@@ -27700,7 +27721,7 @@ static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
     sprintf(errmsg, "create failed (%d)", errno);
     goto end_breaklock;
   }
-  if( pwrite(fd, buf, readLen, 0) != readLen ){
+  if( pwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){
     sprintf(errmsg, "write failed (%d)", errno);
     goto end_breaklock;
   }
@@ -28503,7 +28524,6 @@ SQLITE_API int sqlite3_os_init(void){
     unixSleep,            /* xSleep */                      \
     unixCurrentTime,      /* xCurrentTime */                \
     unixGetLastError,     /* xGetLastError */               \
-    0,                    /* xRename */                     \
     unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
   }
 
@@ -29497,7 +29517,11 @@ static int winWrite(
   rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
   if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
     pFile->lastErrno = error;
-    return SQLITE_FULL;
+    if( pFile->lastErrno==ERROR_HANDLE_DISK_FULL ){
+      return SQLITE_FULL;
+    }else{
+      return SQLITE_IOERR_WRITE;
+    }
   }
   assert( amt>0 );
   while(
@@ -29510,7 +29534,11 @@ static int winWrite(
   }
   if( !rc || amt>(int)wrote ){
     pFile->lastErrno = GetLastError();
-    return SQLITE_FULL;
+    if( pFile->lastErrno==ERROR_HANDLE_DISK_FULL ){
+      return SQLITE_FULL;
+    }else{
+      return SQLITE_IOERR_WRITE;
+    }
   }
   return SQLITE_OK;
 }
@@ -30197,6 +30225,9 @@ static int winShmOpen(
     */
     if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
       rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
+      if( rc!=SQLITE_OK ){
+        rc = SQLITE_IOERR_SHMOPEN;
+      }
     }
     if( rc==SQLITE_OK ){
       winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
@@ -30423,6 +30454,7 @@ static int winShmLock(
 static void winShmBarrier(
   sqlite3_file *fd          /* Database holding the shared memory */
 ){
+  UNUSED_PARAMETER(fd);
   /* MemoryBarrier(); // does not work -- do not know why not */
   winShmEnterMutex();
   winShmLeaveMutex();
@@ -30834,13 +30866,38 @@ static int winAccess(
 ){
   DWORD attr;
   int rc = 0;
-  void *zConverted = convertUtf8Filename(zFilename);
+  void *zConverted;
   UNUSED_PARAMETER(pVfs);
+
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  zConverted = convertUtf8Filename(zFilename);
   if( zConverted==0 ){
     return SQLITE_NOMEM;
   }
   if( isNT() ){
-    attr = GetFileAttributesW((WCHAR*)zConverted);
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    if( GetFileAttributesExW((WCHAR*)zConverted,
+                             GetFileExInfoStandard, 
+                             &sAttrData) ){
+      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
+      ** as if it does not exist.
+      */
+      if(    flags==SQLITE_ACCESS_EXISTS
+          && sAttrData.nFileSizeHigh==0 
+          && sAttrData.nFileSizeLow==0 ){
+        attr = INVALID_FILE_ATTRIBUTES;
+      }else{
+        attr = sAttrData.dwFileAttributes;
+      }
+    }else{
+      if( GetLastError()!=ERROR_FILE_NOT_FOUND ){
+        free(zConverted);
+        return SQLITE_IOERR_ACCESS;
+      }else{
+        attr = INVALID_FILE_ATTRIBUTES;
+      }
+    }
 /* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
 ** Since the ASCII version of these Windows API do not exist for WINCE,
 ** it's important to not reference them for WINCE builds.
@@ -31240,7 +31297,6 @@ SQLITE_API int sqlite3_os_init(void){
     winSleep,            /* xSleep */
     winCurrentTime,      /* xCurrentTime */
     winGetLastError,     /* xGetLastError */
-    0,                   /* xRename */
     winCurrentTimeInt64, /* xCurrentTimeInt64 */
   };
 
@@ -33510,13 +33566,14 @@ SQLITE_PRIVATE int sqlite3RowSetTest(RowSet *pRowSet, u8 iBatch, sqlite3_int64 i
 # define sqlite3WalRead(v,w,x,y,z)             0
 # define sqlite3WalDbsize(y,z)
 # define sqlite3WalBeginWriteTransaction(y)    0
-# define sqlite3WalEndWRiteTransaction(x)      0
+# define sqlite3WalEndWriteTransaction(x)      0
 # define sqlite3WalUndo(x,y,z)                 0
 # define sqlite3WalSavepoint(y,z)
 # define sqlite3WalSavepointUndo(y,z)          0
 # define sqlite3WalFrames(u,v,w,x,y,z)         0
 # define sqlite3WalCheckpoint(u,v,w,x)         0
 # define sqlite3WalCallback(z)                 0
+# define sqlite3WalExclusiveMode(y,z)          0
 #else
 
 #define WAL_SAVEPOINT_NDATA 4
@@ -33790,7 +33847,9 @@ struct PagerSavepoint {
   Bitvec *pInSavepoint;        /* Set of pages in this savepoint */
   Pgno nOrig;                  /* Original number of pages in file */
   Pgno iSubRec;                /* Index of first record in sub-journal */
+#ifndef SQLITE_OMIT_WAL
   u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
+#endif
 };
 
 /*
@@ -33974,6 +34033,7 @@ struct Pager {
   sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
 #ifndef SQLITE_OMIT_WAL
   Wal *pWal;                  /* Write-ahead log used by "journal_mode=wal" */
+  char *zWal;                 /* File name for write-ahead log */
 #endif
 };
 
@@ -35085,6 +35145,21 @@ static u32 pager_cksum(Pager *pPager, const u8 *aData){
 }
 
 /*
+** 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.
 ** The page begins at offset *pOffset into the file. The *pOffset
@@ -35176,12 +35251,21 @@ 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.
@@ -35982,43 +36066,40 @@ static int pagerBeginReadTransaction(Pager *pPager){
 
 /*
 ** Check if the *-wal file that corresponds to the database opened by pPager
-** exists. Assuming no error occurs, set *pExists to 1 if the file exists,
-** or 0 otherwise and return SQLITE_OK. If an IO or OOM error occurs, return
-** an SQLite error code.
-*/
-static int pagerHasWAL(Pager *pPager, int *pExists){
-  int rc;                         /* Return code */
-  char *zWal;                     /* Name of the WAL file */
-
-  assert( !pPager->tempFile );
-  zWal = sqlite3_mprintf("%s-wal", pPager->zFilename);
-  if( !zWal ){
-    rc = SQLITE_NOMEM;
-  }else{
-    rc = sqlite3OsAccess(pPager->pVfs, zWal, SQLITE_ACCESS_EXISTS, pExists);
-    sqlite3_free(zWal);
-  }
-  return rc;
-}
-
-/*
-** Check if the *-wal file that corresponds to the database opened by pPager
-** exists. If it does, open the pager in WAL mode. Otherwise, if no error
-** occurs, make sure Pager.journalMode is not set to PAGER_JOURNALMODE_WAL.
-** If an IO or OOM error occurs, return an SQLite error code.
+** exists if the database is not empy, or verify that the *-wal file does
+** not exist (by deleting it) if the database file is empty.
+**
+** If the database is not empty and the *-wal file exists, open the pager
+** in WAL mode.  If the database is empty or if no *-wal file exists and
+** if no error occurs, make sure Pager.journalMode is not set to
+** PAGER_JOURNALMODE_WAL.
+**
+** Return SQLITE_OK or an error code.
 **
 ** If the WAL file is opened, also open a snapshot (read transaction).
 **
 ** The caller must hold a SHARED lock on the database file to call this
 ** function. Because an EXCLUSIVE lock on the db file is required to delete 
-** a WAL, this ensures there is no race condition between the xAccess() 
-** below and an xDelete() being executed by some other connection.
+** a WAL on a none-empty database, this ensures there is no race condition 
+** between the xAccess() below and an xDelete() being executed by some 
+** other connection.
 */
 static int pagerOpenWalIfPresent(Pager *pPager){
   int rc = SQLITE_OK;
   if( !pPager->tempFile ){
     int isWal;                    /* True if WAL file exists */
-    rc = pagerHasWAL(pPager, &isWal);
+    int nPage;                    /* Size of the database file */
+    assert( pPager->state>=SHARED_LOCK );
+    rc = sqlite3PagerPagecount(pPager, &nPage);
+    if( rc ) return rc;
+    if( nPage==0 ){
+      rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
+      isWal = 0;
+    }else{
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
+      );
+    }
     if( rc==SQLITE_OK ){
       if( isWal ){
         pager_reset(pPager);
@@ -36292,21 +36373,6 @@ SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(
 }
 
 /*
-** 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.
 **
@@ -36392,7 +36458,7 @@ SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
   }
   if( pPager->state!=PAGER_UNLOCK ){
     sqlite3PagerPagecount(pPager, &nPage);
-    assert( pPager->mxPgno>=nPage );
+    assert( (int)pPager->mxPgno>=nPage );
   }
   return pPager->mxPgno;
 }
@@ -36445,15 +36511,6 @@ SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned cha
   ** 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))
@@ -36897,13 +36954,9 @@ static int syncJournal(Pager *pPager){
 ** occurs, an IO error code is returned. Or, if the EXCLUSIVE lock cannot
 ** be obtained, SQLITE_BUSY is returned.
 */
-static int pager_write_pagelist(PgHdr *pList){
-  Pager *pPager;                       /* Pager object */
+static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
   int rc;                              /* Return code */
 
-  if( NEVER(pList==0) ) return SQLITE_OK;
-  pPager = pList->pPager;
-
   /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
   ** database file. If there is already an EXCLUSIVE lock, the following
   ** call is a no-op.
@@ -36920,7 +36973,7 @@ static int pager_write_pagelist(PgHdr *pList){
   ** EXCLUSIVE, it means the database file has been changed and any rollback
   ** will require a journal playback.
   */
-  assert( !pagerUseWal(pList->pPager) );
+  assert( !pagerUseWal(pPager) );
   assert( pPager->state>=PAGER_RESERVED );
   rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
 
@@ -37165,7 +37218,7 @@ static int pagerStress(void *p, PgHdr *pPg){
   
     /* Write the contents of the page out to the database file. */
     if( rc==SQLITE_OK ){
-      rc = pager_write_pagelist(pPg);
+      rc = pager_write_pagelist(pPager, pPg);
     }
   }
 
@@ -37305,6 +37358,9 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
     journalFileSize * 2 +          /* The two journal files */ 
     nPathname + 1 +                /* zFilename */
     nPathname + 8 + 1              /* zJournal */
+#ifndef SQLITE_OMIT_WAL
+    + nPathname + 4 + 1              /* zWal */
+#endif
   );
   assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
   if( !pPtr ){
@@ -37325,7 +37381,16 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
     memcpy(pPager->zFilename, zPathname, nPathname);
     memcpy(pPager->zJournal, zPathname, nPathname);
     memcpy(&pPager->zJournal[nPathname], "-journal", 8);
-    if( pPager->zFilename[0]==0 ) pPager->zJournal[0] = 0;
+    if( pPager->zFilename[0]==0 ){
+      pPager->zJournal[0] = 0;
+    }
+#ifndef SQLITE_OMIT_WAL
+    else{
+      pPager->zWal = &pPager->zJournal[nPathname+8+1];
+      memcpy(pPager->zWal, zPathname, nPathname);
+      memcpy(&pPager->zWal[nPathname], "-wal", 4);
+    }
+#endif
     sqlite3_free(zPathname);
   }
   pPager->pVfs = pVfs;
@@ -38201,30 +38266,19 @@ SQLITE_PRIVATE int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory
     ** we might save the work of creating a file if the transaction
     ** ends up being a no-op.
     */
-  }else if( isOpen(pPager->jfd) && pPager->journalOff==0 ){
-    /* This happens when the pager was in exclusive-access mode the last
-    ** time a (read or write) transaction was successfully concluded
-    ** by this connection. Instead of deleting the journal file it was 
-    ** kept open and either was truncated to 0 bytes or its header was
-    ** overwritten with zeros.
-    */
-    assert( pagerUseWal(pPager)==0 );
-    assert( pPager->nRec==0 );
-    assert( pPager->dbOrigSize==0 );
-    assert( pPager->pInJournal==0 );
-    rc = pager_open_journal(pPager);
+
+    if( rc!=SQLITE_OK ){
+      assert( !pPager->dbModified );
+      /* Ignore any IO error that occurs within pager_end_transaction(). The
+      ** purpose of this call is to reset the internal state of the pager
+      ** sub-system. It doesn't matter if the journal-file is not properly
+      ** finalized at this point (since it is not a valid journal file anyway).
+      */
+      pager_end_transaction(pPager, 0);
+    }
   }
 
   PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
-  if( rc!=SQLITE_OK ){
-    assert( !pPager->dbModified );
-    /* Ignore any IO error that occurs within pager_end_transaction(). The
-    ** purpose of this call is to reset the internal state of the pager
-    ** sub-system. It doesn't matter if the journal-file is not properly
-    ** finalized at this point (since it is not a valid journal file anyway).
-    */
-    pager_end_transaction(pPager, 0);
-  }
   return rc;
 }
 
@@ -38275,10 +38329,7 @@ static int pager_write(PgHdr *pPg){
     ** which means they have acquired the necessary locks but the rollback
     ** journal might not yet be open.
     */
-    rc = sqlite3PagerBegin(pPager, 0, pPager->subjInMemory);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
+    assert( pPager->state>=RESERVED_LOCK );
     if( pPager->pInJournal==0
      && pPager->journalMode!=PAGER_JOURNALMODE_OFF 
      && !pagerUseWal(pPager)
@@ -38719,7 +38770,10 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
       */
   #ifdef SQLITE_ENABLE_ATOMIC_WRITE
       PgHdr *pPg;
-      assert( isOpen(pPager->jfd) || pPager->journalMode==PAGER_JOURNALMODE_OFF );
+      assert( isOpen(pPager->jfd) 
+           || pPager->journalMode==PAGER_JOURNALMODE_OFF 
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL 
+      );
       if( !zMaster && isOpen(pPager->jfd) 
        && pPager->journalOff==jrnlBufferSize(pPager) 
        && pPager->dbSize>=pPager->dbFileSize
@@ -38793,7 +38847,7 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
       if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
   
       /* Write all dirty pages to the database file. */
-      rc = pager_write_pagelist(sqlite3PcacheDirtyList(pPager->pPCache));
+      rc = pager_write_pagelist(pPager,sqlite3PcacheDirtyList(pPager->pPCache));
       if( rc!=SQLITE_OK ){
         assert( rc!=SQLITE_IOERR_BLOCKED );
         goto commit_phase_one_exit;
@@ -38853,7 +38907,7 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
   ** fails - make it so that we never reach this point if we do not hold
   ** all necessary locks.
   */
-  if( pPager->state<PAGER_RESERVED ) return SQLITE_ERROR;
+  if( NEVER(pPager->state<PAGER_RESERVED) ) return SQLITE_ERROR;
 
   /* An optimization. If the database was not actually modified during
   ** this transaction, the pager is running in exclusive-mode and is
@@ -38869,7 +38923,7 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
   if( pPager->dbModified==0 && pPager->exclusiveMode 
    && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
   ){
-    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
+    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
     return SQLITE_OK;
   }
 
@@ -39203,7 +39257,7 @@ SQLITE_PRIVATE int sqlite3PagerNosync(Pager *pPager){
 /*
 ** Set or retrieve the codec for this pager
 */
-static void sqlite3PagerSetCodec(
+SQLITE_PRIVATE void sqlite3PagerSetCodec(
   Pager *pPager,
   void *(*xCodec)(void*,void*,Pgno,int),
   void (*xCodecSizeChng)(void*,int,int),
@@ -39217,7 +39271,7 @@ static void sqlite3PagerSetCodec(
   pPager->pCodec = pCodec;
   pagerReportSize(pPager);
 }
-static void *sqlite3PagerGetCodec(Pager *pPager){
+SQLITE_PRIVATE void *sqlite3PagerGetCodec(Pager *pPager){
   return pPager->pCodec;
 }
 #endif
@@ -39541,7 +39595,7 @@ SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager *pPager){
 */
 SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
   if( pPager->dbModified ) return 0;
-  if( isOpen(pPager->jfd) && pPager->journalOff>0 ) return 0;
+  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
   return 1;
 }
 
@@ -39598,25 +39652,37 @@ SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
 }
 
 /*
-** Open a connection to the write-ahead log file for pager pPager. If
-** the log connection is already open, this function is a no-op.
-**
 ** The caller must be holding a SHARED lock on the database file to call
 ** this function.
+**
+** If the pager passed as the first argument is open on a real database
+** file (not a temp file or an in-memory database), and the WAL file
+** is not already open, make an attempt to open it now. If successful,
+** return SQLITE_OK. If an error occurs or the VFS used by the pager does 
+** not support the xShmXXX() methods, return an error code. *pisOpen is
+** not modified in either case.
+**
+** If the pager is open on a temp-file (or in-memory database), or if
+** the WAL file is already open, set *pisOpen to 1 and return SQLITE_OK
+** without doing anything.
 */
-SQLITE_PRIVATE int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen){
+SQLITE_PRIVATE int sqlite3PagerOpenWal(
+  Pager *pPager,                  /* Pager object */
+  int *pisOpen                    /* OUT: Set to true if call is a no-op */
+){
   int rc = SQLITE_OK;             /* Return code */
 
   assert( pPager->state>=PAGER_SHARED );
-  if( !pPager->pWal ){
+  assert( (pisOpen==0 && !pPager->tempFile && !pPager->pWal) || *pisOpen==0 );
+
+  if( !pPager->tempFile && !pPager->pWal ){
     if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;
 
     /* Open the connection to the log file. If this operation fails, 
     ** (e.g. due to malloc() failure), unlock the database file and 
     ** return an error code.
     */
-    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
-                        pPager->zFilename, &pPager->pWal);
+    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd, pPager->zWal, &pPager->pWal);
     if( rc==SQLITE_OK ){
       pPager->journalMode = PAGER_JOURNALMODE_WAL;
     }
@@ -39649,11 +39715,13 @@ SQLITE_PRIVATE int sqlite3PagerCloseWal(Pager *pPager){
     int logexists = 0;
     rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
     if( rc==SQLITE_OK ){
-      rc = pagerHasWAL(pPager, &logexists);
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
+      );
     }
     if( rc==SQLITE_OK && logexists ){
       rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
-                          pPager->zFilename, &pPager->pWal);
+                          pPager->zWal, &pPager->pWal);
     }
   }
     
@@ -40095,7 +40163,7 @@ struct WalCkptInfo {
 ** is to the start of the write-ahead log frame-header.
 */
 #define walFrameOffset(iFrame, szPage) (                               \
-  WAL_HDRSIZE + ((iFrame)-1)*((szPage)+WAL_FRAME_HDRSIZE)        \
+  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
 )
 
 /*
@@ -40116,7 +40184,7 @@ struct Wal {
   u8 writeLock;              /* True if in a write transaction */
   u8 ckptLock;               /* True if holding a checkpoint lock */
   WalIndexHdr hdr;           /* Wal-index header for current transaction */
-  char *zWalName;            /* Name of WAL file */
+  const char *zWalName;      /* Name of WAL file */
   u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
 #ifdef SQLITE_DEBUG
   u8 lockError;              /* True if a locking error has occurred */
@@ -40196,12 +40264,12 @@ static int walIndexPage(Wal *pWal, int iPage, volatile u32 **ppPage){
   if( pWal->nWiData<=iPage ){
     int nByte = sizeof(u32 *)*(iPage+1);
     volatile u32 **apNew;
-    apNew = (volatile u32 **)sqlite3_realloc(pWal->apWiData, nByte);
+    apNew = (volatile u32 **)sqlite3_realloc((void *)pWal->apWiData, nByte);
     if( !apNew ){
       *ppPage = 0;
       return SQLITE_NOMEM;
     }
-    memset(&apNew[pWal->nWiData], 0, sizeof(u32 *)*(iPage+1-pWal->nWiData));
+    memset((void *)&apNew[pWal->nWiData], 0, sizeof(u32 *)*(iPage+1-pWal->nWiData));
     pWal->apWiData = apNew;
     pWal->nWiData = iPage+1;
   }
@@ -40436,7 +40504,7 @@ static int walLockShared(Wal *pWal, int lockIdx){
                         SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
   WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
             walLockName(lockIdx), rc ? "failed" : "ok"));
-  VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
   return rc;
 }
 static void walUnlockShared(Wal *pWal, int lockIdx){
@@ -40452,7 +40520,7 @@ static int walLockExclusive(Wal *pWal, int lockIdx, int n){
                         SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
   WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
             walLockName(lockIdx), n, rc ? "failed" : "ok"));
-  VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
   return rc;
 }
 static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
@@ -40600,7 +40668,7 @@ static void walCleanupHash(Wal *pWal){
   /* Zero the entries in the aPgno array that correspond to frames with
   ** frame numbers greater than pWal->hdr.mxFrame. 
   */
-  nByte = ((char *)aHash - (char *)&aPgno[iLimit+1]);
+  nByte = (int)((char *)aHash - (char *)&aPgno[iLimit+1]);
   memset((void *)&aPgno[iLimit+1], 0, nByte);
 
 #ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
@@ -40648,7 +40716,7 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
     ** entire hash table and aPgno[] array before proceding. 
     */
     if( idx==1 ){
-      int nByte = (u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1];
+      int nByte = (int)((u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1]);
       memset((void*)&aPgno[1], 0, nByte);
     }
 
@@ -40668,7 +40736,7 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
       assert( nCollide++ < idx );
     }
     aPgno[idx] = iPage;
-    aHash[iKey] = idx;
+    aHash[iKey] = (ht_slot)idx;
 
 #ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
     /* Verify that the number of entries in the hash table exactly equals
@@ -40776,8 +40844,8 @@ static int walIndexRecover(Wal *pWal){
     ){
       goto finished;
     }
-    pWal->hdr.bigEndCksum = (magic&0x00000001);
-    pWal->szPage = szPage;
+    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
+    pWal->szPage = (u16)szPage;
     pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
     memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);
 
@@ -40827,7 +40895,7 @@ static int walIndexRecover(Wal *pWal){
       if( nTruncate ){
         pWal->hdr.mxFrame = iFrame;
         pWal->hdr.nPage = nTruncate;
-        pWal->hdr.szPage = szPage;
+        pWal->hdr.szPage = (u16)szPage;
         aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
         aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
       }
@@ -40871,8 +40939,9 @@ static void walIndexClose(Wal *pWal, int isDelete){
 }
 
 /* 
-** Open a connection to the WAL file associated with database zDbName.
-** The database file must already be opened on connection pDbFd.
+** Open a connection to the WAL file zWalName. The database file must 
+** already be opened on connection pDbFd. The buffer that zWalName points
+** to must remain valid for the lifetime of the returned Wal* handle.
 **
 ** A SHARED lock should be held on the database file when this function
 ** is called. The purpose of this SHARED lock is to prevent any other
@@ -40887,16 +40956,14 @@ static void walIndexClose(Wal *pWal, int isDelete){
 SQLITE_PRIVATE int sqlite3WalOpen(
   sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
   sqlite3_file *pDbFd,            /* The open database file */
-  const char *zDbName,            /* Name of the database file */
+  const char *zWalName,           /* Name of the WAL file */
   Wal **ppWal                     /* OUT: Allocated Wal handle */
 ){
   int rc;                         /* Return Code */
   Wal *pRet;                      /* Object to allocate and return */
   int flags;                      /* Flags passed to OsOpen() */
-  char *zWal;                     /* Name of write-ahead log file */
-  int nWal;                       /* Length of zWal in bytes */
 
-  assert( zDbName && zDbName[0] );
+  assert( zWalName && zWalName[0] );
   assert( pDbFd );
 
   /* In the amalgamation, the os_unix.c and os_win.c source files come before
@@ -40913,8 +40980,7 @@ SQLITE_PRIVATE int sqlite3WalOpen(
 
   /* Allocate an instance of struct Wal to return. */
   *ppWal = 0;
-  nWal = sqlite3Strlen30(zDbName) + 5;
-  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile + nWal);
+  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile);
   if( !pRet ){
     return SQLITE_NOMEM;
   }
@@ -40924,15 +40990,14 @@ SQLITE_PRIVATE int sqlite3WalOpen(
   pRet->pDbFd = pDbFd;
   pRet->readLock = -1;
   sqlite3_randomness(8, &pRet->hdr.aSalt);
-  pRet->zWalName = zWal = pVfs->szOsFile + (char*)pRet->pWalFd;
-  sqlite3_snprintf(nWal, zWal, "%s-wal", zDbName);
+  pRet->zWalName = zWalName;
   rc = sqlite3OsShmOpen(pDbFd);
 
   /* Open file handle on the write-ahead log file. */
   if( rc==SQLITE_OK ){
     pRet->isWIndexOpen = 1;
     flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MAIN_JOURNAL);
-    rc = sqlite3OsOpen(pVfs, zWal, pRet->pWalFd, flags, &flags);
+    rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
   }
 
   if( rc!=SQLITE_OK ){
@@ -41155,12 +41220,12 @@ static int walIteratorInit(Wal *pWal, WalIterator **pp){
       ht_slot *aIndex;            /* Sorted index for this segment */
 
       aPgno++;
-      nEntry = ((i+1)==nSegment)?(int)(iLast-iZero):(u32 *)aHash-(u32 *)aPgno;
+      nEntry = (int)(((i+1)==nSegment)?(int)(iLast-iZero):(u32 *)aHash-(u32 *)aPgno);
       aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[iZero];
       iZero++;
   
       for(j=0; j<nEntry; j++){
-        aIndex[j] = j;
+        aIndex[j] = (ht_slot)j;
       }
       walMergesort((u32 *)aPgno, aTmp, aIndex, &nEntry);
       p->aSegment[i].iZero = iZero;
@@ -41274,20 +41339,25 @@ static int walCheckpoint(
 
     /* Iterate through the contents of the WAL, copying data to the db file. */
     while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
+      i64 iOffset;
       assert( walFramePgno(pWal, iFrame)==iDbpage );
       if( iFrame<=nBackfill || iFrame>mxSafeFrame ) continue;
-      rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, 
-          walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE
-      );
+      iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
+      /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
+      rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
       if( rc!=SQLITE_OK ) break;
-      rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, (iDbpage-1)*szPage);
+      iOffset = (iDbpage-1)*(i64)szPage;
+      testcase( IS_BIG_INT(iOffset) );
+      rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
       if( rc!=SQLITE_OK ) break;
     }
 
     /* If work was actually accomplished... */
     if( rc==SQLITE_OK ){
       if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
-        rc = sqlite3OsTruncate(pWal->pDbFd, ((i64)pWal->hdr.nPage*(i64)szPage));
+        i64 szDb = pWal->hdr.nPage*(i64)szPage;
+        testcase( IS_BIG_INT(szDb) );
+        rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
         if( rc==SQLITE_OK && sync_flags ){
           rc = sqlite3OsSync(pWal->pDbFd, sync_flags);
         }
@@ -41347,7 +41417,7 @@ SQLITE_PRIVATE int sqlite3WalClose(
       sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
     }
     WALTRACE(("WAL%p: closed\n", pWal));
-    sqlite3_free(pWal->apWiData);
+    sqlite3_free((void *)pWal->apWiData);
     sqlite3_free(pWal);
   }
   return rc;
@@ -41683,7 +41753,7 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){
       return WAL_RETRY;
     }else{
       assert( mxReadMark<=pWal->hdr.mxFrame );
-      pWal->readLock = mxI;
+      pWal->readLock = (i16)mxI;
     }
   }
   return rc;
@@ -41825,6 +41895,7 @@ SQLITE_PRIVATE int sqlite3WalRead(
   if( iRead ){
     i64 iOffset = walFrameOffset(iRead, pWal->hdr.szPage) + WAL_FRAME_HDRSIZE;
     *pInWal = 1;
+    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
     return sqlite3OsRead(pWal->pWalFd, pOut, nOut, iOffset);
   }
 
@@ -42096,7 +42167,7 @@ SQLITE_PRIVATE int sqlite3WalFrames(
     sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
     sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
     
-    pWal->szPage = szPage;
+    pWal->szPage = (u16)szPage;
     pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
     pWal->hdr.aFrameCksum[0] = aCksum[0];
     pWal->hdr.aFrameCksum[1] = aCksum[1];
@@ -42115,8 +42186,8 @@ SQLITE_PRIVATE int sqlite3WalFrames(
     i64 iOffset;                  /* Write offset in log file */
     void *pData;
    
-   
     iOffset = walFrameOffset(++iFrame, szPage);
+    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
     
     /* Populate and write the frame header */
     nDbsize = (isCommit && p->pDirty==0) ? nTruncate : 0;
@@ -42156,6 +42227,7 @@ SQLITE_PRIVATE int sqlite3WalFrames(
       pData = pLast->pData;
 #endif
       walEncodeFrame(pWal, pLast->pgno, nTruncate, pData, aFrame);
+      /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
       rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOffset);
       if( rc!=SQLITE_OK ){
         return rc;
@@ -42190,7 +42262,7 @@ SQLITE_PRIVATE int sqlite3WalFrames(
 
   if( rc==SQLITE_OK ){
     /* Update the private copy of the header. */
-    pWal->hdr.szPage = szPage;
+    pWal->hdr.szPage = (u16)szPage;
     pWal->hdr.mxFrame = iFrame;
     if( isCommit ){
       pWal->hdr.iChange++;
@@ -44927,16 +44999,20 @@ static int getAndInitPage(
   int rc;
   assert( sqlite3_mutex_held(pBt->mutex) );
 
-  if( pgno<=0 || pgno>btreePagecount(pBt) ){
-    return SQLITE_CORRUPT_BKPT;
-  }
-  rc = btreeGetPage(pBt, pgno, ppPage, 0);
-  if( rc==SQLITE_OK ){
-    rc = btreeInitPage(*ppPage);
-    if( rc!=SQLITE_OK ){
-      releasePage(*ppPage);
+  if( pgno>btreePagecount(pBt) ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }else{
+    rc = btreeGetPage(pBt, pgno, ppPage, 0);
+    if( rc==SQLITE_OK ){
+      rc = btreeInitPage(*ppPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(*ppPage);
+      }
     }
   }
+
+  testcase( pgno==0 );
+  assert( pgno!=0 || rc==SQLITE_CORRUPT );
   return rc;
 }
 
@@ -45863,7 +45939,7 @@ SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
   rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
   if( SQLITE_OK!=rc ) goto trans_begun;
 
-  pBt->initiallyEmpty = pBt->nPage==0;
+  pBt->initiallyEmpty = (u8)(pBt->nPage==0);
   do {
     /* Call lockBtree() until either pBt->pPage1 is populated or
     ** lockBtree() returns something other than SQLITE_OK. lockBtree()
@@ -47586,7 +47662,6 @@ SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
     if( pCur->eState==CURSOR_INVALID ){
       assert( pCur->apPage[pCur->iPage]->nCell==0 );
       *pRes = 1;
-      rc = SQLITE_OK;
     }else{
       assert( pCur->apPage[pCur->iPage]->nCell>0 );
       *pRes = 0;
@@ -51351,7 +51426,7 @@ SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
   /* If setting the version fields to 1, do not automatically open the
   ** WAL connection, even if the version fields are currently set to 2.
   */
-  pBt->doNotUseWAL = (iVersion==1);
+  pBt->doNotUseWAL = (u8)(iVersion==1);
 
   rc = sqlite3BtreeBeginTrans(pBtree, 0);
   if( rc==SQLITE_OK ){
@@ -51843,6 +51918,9 @@ SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage){
       assert( rc2==SQLITE_OK );
     }
   
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM;
+    }
     p->rc = rc;
   }
   if( p->pDestDb ){
@@ -53965,7 +54043,9 @@ SQLITE_PRIVATE void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
 ** check the value of p->nOp-1 before continuing.
 */
 SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
-  static const VdbeOp dummy;
+  /* C89 specifies that the constant "dummy" will be initialized to all
+  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
+  static const VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
   assert( p->magic==VDBE_MAGIC_INIT );
   if( addr<0 ){
 #ifdef SQLITE_OMIT_TRACE
@@ -62396,14 +62476,13 @@ case OP_Rewind: {        /* jump */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bl.pC = p->apCsr[pOp->p1];
   assert( u.bl.pC!=0 );
+  u.bl.res = 1;
   if( (u.bl.pCrsr = u.bl.pC->pCursor)!=0 ){
     rc = sqlite3BtreeFirst(u.bl.pCrsr, &u.bl.res);
     u.bl.pC->atFirst = u.bl.res==0 ?1:0;
     u.bl.pC->deferredMoveto = 0;
     u.bl.pC->cacheStatus = CACHE_STALE;
     u.bl.pC->rowidIsValid = 0;
-  }else{
-    u.bl.res = 1;
   }
   u.bl.pC->nullRow = (u8)u.bl.res;
   assert( pOp->p2>0 && pOp->p2<p->nOp );
@@ -63447,6 +63526,7 @@ case OP_Checkpoint: {
 };  
 #endif
 
+#ifndef SQLITE_OMIT_PRAGMA
 /* Opcode: JournalMode P1 P2 P3 * P5
 **
 ** Change the journal mode of database P1 to P3. P3 must be one of the
@@ -63573,7 +63653,8 @@ case OP_JournalMode: {    /* out2-prerelease */
   pOut->enc = SQLITE_UTF8;
   sqlite3VdbeChangeEncoding(pOut, encoding);
   break;
-};  
+};
+#endif /* SQLITE_OMIT_PRAGMA */
 
 #if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
 /* Opcode: Vacuum * * * * *
@@ -64757,7 +64838,12 @@ static struct sqlite3_io_methods JournalFileMethods = {
   0,             /* xCheckReservedLock */
   0,             /* xFileControl */
   0,             /* xSectorSize */
-  0              /* xDeviceCharacteristics */
+  0,             /* xDeviceCharacteristics */
+  0,             /* xShmOpen */
+  0,             /* xShmLock */
+  0,             /* xShmMap */
+  0,             /* xShmBarrier */
+  0              /* xShmClose */
 };
 
 /* 
@@ -83535,6 +83621,10 @@ SQLITE_PRIVATE void sqlite3Pragma(
   if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
     int eMode;                    /* One of the PAGER_JOURNALMODE_XXX symbols */
 
+    if( sqlite3ReadSchema(pParse) ){
+      goto pragma_out;
+    }
+
     sqlite3VdbeSetNumCols(v, 1);
     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "journal_mode", SQLITE_STATIC);
 
@@ -83543,7 +83633,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
     }else{
       const char *zMode;
       int n = sqlite3Strlen30(zRight);
-      for(eMode=0; (zMode = sqlite3JournalModename(eMode)); eMode++){
+      for(eMode=0; (zMode = sqlite3JournalModename(eMode))!=0; eMode++){
         if( sqlite3StrNICmp(zRight, zMode, n)==0 ) break;
       }
       if( !zMode ){
@@ -84598,12 +84688,15 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
     */
     int rc;
     sqlite3_stmt *pStmt;
+    TESTONLY(int rcp);            /* Return code from sqlite3_prepare() */
 
     assert( db->init.busy );
     db->init.iDb = iDb;
     db->init.newTnum = atoi(argv[1]);
     db->init.orphanTrigger = 0;
-    rc = sqlite3_prepare(db, argv[2], -1, &pStmt, 0);
+    TESTONLY(rcp = ) sqlite3_prepare(db, argv[2], -1, &pStmt, 0);
+    rc = db->errCode;
+    assert( (rc&0xFF)==(rcp&0xFF) );
     db->init.iDb = 0;
     if( SQLITE_OK!=rc ){
       if( db->init.orphanTrigger ){
@@ -84612,7 +84705,7 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
         pData->rc = rc;
         if( rc==SQLITE_NOMEM ){
           db->mallocFailed = 1;
-        }else if( rc!=SQLITE_INTERRUPT && rc!=SQLITE_LOCKED ){
+        }else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){
           corruptSchema(pData, argv[0], sqlite3_errmsg(db));
         }
       }
@@ -94779,7 +94872,7 @@ static void constructAutomaticIndex(
       }
     }
   }
-  assert( n==pLevel->plan.nEq );
+  assert( (u32)n==pLevel->plan.nEq );
 
   /* Add additional columns needed to make the automatic index into
   ** a covering index */
@@ -96373,7 +96466,7 @@ static Bitmask codeOneLoopStart(
     ** a forward order scan on a descending index, interchange the 
     ** start and end terms (pRangeStart and pRangeEnd).
     */
-    if( bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
+    if( nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
       SWAP(WhereTerm *, pRangeEnd, pRangeStart);
     }
 
@@ -104088,7 +104181,6 @@ SQLITE_API int sqlite3_collation_needed16(
 }
 #endif /* SQLITE_OMIT_UTF16 */
 
-#ifndef SQLITE_OMIT_GLOBALRECOVER
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
 ** This function is now an anachronism. It used to be used to recover from a
@@ -104098,7 +104190,6 @@ SQLITE_API int sqlite3_global_recover(void){
   return SQLITE_OK;
 }
 #endif
-#endif
 
 /*
 ** Test to see whether or not the database connection is in autocommit
@@ -106073,6 +106164,9 @@ static int fts3CreateTables(Fts3Table *p){
 ** An sqlite3_exec() callback for fts3TableExists.
 */
 static int fts3TableExistsCallback(void *pArg, int n, char **pp1, char **pp2){
+  UNUSED_PARAMETER(n);
+  UNUSED_PARAMETER(pp1);
+  UNUSED_PARAMETER(pp2);
   *(int*)pArg = 1;
   return 1;
 }
@@ -106098,7 +106192,7 @@ static void fts3TableExists(
   );    
   rc = sqlite3_exec(db, zSql, fts3TableExistsCallback, &res, 0);
   sqlite3_free(zSql);
-  *pResult = res & 0xff;
+  *pResult = (u8)(res & 0xff);
   if( rc!=SQLITE_ABORT ) *pRc = rc;
 }
 
diff --git a/dist/sqlite3.c.orig b/dist/sqlite3.c.orig
index 5058edf..2ac17c8 100644
--- a/dist/sqlite3.c.orig
+++ b/dist/sqlite3.c.orig
@@ -512,6 +512,13 @@ SQLITE_PRIVATE   void sqlite3Coverage(int);
 #endif
 
 /*
+** Return true (non-zero) if the input is a integer that is too large
+** to fit in 32-bits.  This macro is used inside of various testcase()
+** macros to verify that we have tested SQLite for large-file support.
+*/
+#define IS_BIG_INT(X)  (((X)&(i64)0xffffffff)!=0)
+
+/*
 ** The macro unlikely() is a hint that surrounds a boolean
 ** expression that is usually false.  Macro likely() surrounds
 ** a boolean expression that is usually true.  GCC is able to
@@ -638,7 +645,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.7.0"
 #define SQLITE_VERSION_NUMBER 3007000
-#define SQLITE_SOURCE_ID      "2010-06-28 10:15:20 4932f22848b3d15a2b6dc5fa2cd69ce19182e2a4"
+#define SQLITE_SOURCE_ID      "2010-07-07 14:45:41 8eefc287265443ec043bdab629597e79c9d22006"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
@@ -1361,16 +1368,23 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** handled as a fatal error by SQLite, vfs implementations should endeavor
 ** to prevent this by setting mxPathname to a sufficiently large value.
 **
-** The xRandomness(), xSleep(), and xCurrentTime() interfaces
-** are not strictly a part of the filesystem, but they are
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
 ** included in the VFS structure for completeness.
 ** The xRandomness() function attempts to return nBytes bytes
 ** of good-quality randomness into zOut.  The return value is
 ** the actual number of bytes of randomness obtained.
 ** The xSleep() method causes the calling thread to sleep for at
 ** least the number of microseconds given.  The xCurrentTime()
-** method returns a Julian Day Number for the current date and time.
-**
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multipled by 86400000 (the number of milliseconds in 
+** a 24-hour day).  
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or 
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 */
 typedef struct sqlite3_vfs sqlite3_vfs;
 struct sqlite3_vfs {
@@ -1397,7 +1411,6 @@ struct sqlite3_vfs {
   ** The methods above are in version 1 of the sqlite_vfs object
   ** definition.  Those that follow are added in version 2 or later
   */
-  int (*xRename)(sqlite3_vfs*, const char *zOld, const char *zNew, int dirSync);
   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
   /*
   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
@@ -11329,9 +11342,11 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_OMIT_CHECK
   "OMIT_CHECK",
 #endif
-#ifdef SQLITE_OMIT_COMPILEOPTION_DIAGS
-  "OMIT_COMPILEOPTION_DIAGS",
-#endif
+/* // redundant
+** #ifdef SQLITE_OMIT_COMPILEOPTION_DIAGS
+**   "OMIT_COMPILEOPTION_DIAGS",
+** #endif
+*/
 #ifdef SQLITE_OMIT_COMPLETE
   "OMIT_COMPLETE",
 #endif
@@ -11365,9 +11380,6 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_OMIT_GET_TABLE
   "OMIT_GET_TABLE",
 #endif
-#ifdef SQLITE_OMIT_GLOBALRECOVER
-  "OMIT_GLOBALRECOVER",
-#endif
 #ifdef SQLITE_OMIT_INCRBLOB
   "OMIT_INCRBLOB",
 #endif
@@ -11446,6 +11458,9 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_OMIT_VIRTUALTABLE
   "OMIT_VIRTUALTABLE",
 #endif
+#ifdef SQLITE_OMIT_WAL
+  "OMIT_WAL",
+#endif
 #ifdef SQLITE_OMIT_WSD
   "OMIT_WSD",
 #endif
@@ -12797,8 +12812,10 @@ SQLITE_PRIVATE void sqlite3RegisterDateTimeFunctions(void){
 **     sqlite3OsLock()
 **
 */
-#if defined(SQLITE_TEST) && (SQLITE_OS_WIN==0)
-  #define DO_OS_MALLOC_TEST(x) if (!x || !sqlite3IsMemJournal(x)) {     \
+#if defined(SQLITE_TEST)
+SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
+  #define DO_OS_MALLOC_TEST(x)                                       \
+  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) {  \
     void *pTstAlloc = sqlite3Malloc(10);                             \
     if (!pTstAlloc) return SQLITE_IOERR_NOMEM;                       \
     sqlite3_free(pTstAlloc);                                         \
@@ -27486,7 +27503,7 @@ static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
   
   /* transform the db path to a unique cache name */
   dbLen = (int)strlen(dbPath);
-  for( i=0; i<dbLen && (i+len+7)<maxLen; i++){
+  for( i=0; i<dbLen && (i+len+7)<(int)maxLen; i++){
     char c = dbPath[i];
     lPath[i+len] = (c=='/')?'_':c;
   }
@@ -27627,6 +27644,9 @@ SQLITE_API int sqlite3_hostid_num = 0;
 
 #define PROXY_HOSTIDLEN    16  /* conch file host id length */
 
+/* Not always defined in the headers as it ought to be */
+extern int gethostuuid(uuid_t id, const struct timespec *wait);
+
 /* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN 
 ** bytes of writable memory.
 */
@@ -27676,6 +27696,7 @@ static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
   char errmsg[64] = "";
   int fd = -1;
   int rc = -1;
+  UNUSED_PARAMETER(myHostID);
 
   /* create a new path by replace the trailing '-conch' with '-break' */
   pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
@@ -27696,7 +27717,7 @@ static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
     sprintf(errmsg, "create failed (%d)", errno);
     goto end_breaklock;
   }
-  if( pwrite(fd, buf, readLen, 0) != readLen ){
+  if( pwrite(fd, buf, readLen, 0) != (ssize_t)readLen ){
     sprintf(errmsg, "write failed (%d)", errno);
     goto end_breaklock;
   }
@@ -28499,7 +28520,6 @@ SQLITE_API int sqlite3_os_init(void){
     unixSleep,            /* xSleep */                      \
     unixCurrentTime,      /* xCurrentTime */                \
     unixGetLastError,     /* xGetLastError */               \
-    0,                    /* xRename */                     \
     unixCurrentTimeInt64, /* xCurrentTimeInt64 */           \
   }
 
@@ -29493,7 +29513,11 @@ static int winWrite(
   rc = SetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);
   if( rc==INVALID_SET_FILE_POINTER && (error=GetLastError())!=NO_ERROR ){
     pFile->lastErrno = error;
-    return SQLITE_FULL;
+    if( pFile->lastErrno==ERROR_HANDLE_DISK_FULL ){
+      return SQLITE_FULL;
+    }else{
+      return SQLITE_IOERR_WRITE;
+    }
   }
   assert( amt>0 );
   while(
@@ -29506,7 +29530,11 @@ static int winWrite(
   }
   if( !rc || amt>(int)wrote ){
     pFile->lastErrno = GetLastError();
-    return SQLITE_FULL;
+    if( pFile->lastErrno==ERROR_HANDLE_DISK_FULL ){
+      return SQLITE_FULL;
+    }else{
+      return SQLITE_IOERR_WRITE;
+    }
   }
   return SQLITE_OK;
 }
@@ -30193,6 +30221,9 @@ static int winShmOpen(
     */
     if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
       rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
+      if( rc!=SQLITE_OK ){
+        rc = SQLITE_IOERR_SHMOPEN;
+      }
     }
     if( rc==SQLITE_OK ){
       winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
@@ -30419,6 +30450,7 @@ static int winShmLock(
 static void winShmBarrier(
   sqlite3_file *fd          /* Database holding the shared memory */
 ){
+  UNUSED_PARAMETER(fd);
   /* MemoryBarrier(); // does not work -- do not know why not */
   winShmEnterMutex();
   winShmLeaveMutex();
@@ -30830,13 +30862,38 @@ static int winAccess(
 ){
   DWORD attr;
   int rc = 0;
-  void *zConverted = convertUtf8Filename(zFilename);
+  void *zConverted;
   UNUSED_PARAMETER(pVfs);
+
+  SimulateIOError( return SQLITE_IOERR_ACCESS; );
+  zConverted = convertUtf8Filename(zFilename);
   if( zConverted==0 ){
     return SQLITE_NOMEM;
   }
   if( isNT() ){
-    attr = GetFileAttributesW((WCHAR*)zConverted);
+    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
+    memset(&sAttrData, 0, sizeof(sAttrData));
+    if( GetFileAttributesExW((WCHAR*)zConverted,
+                             GetFileExInfoStandard, 
+                             &sAttrData) ){
+      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
+      ** as if it does not exist.
+      */
+      if(    flags==SQLITE_ACCESS_EXISTS
+          && sAttrData.nFileSizeHigh==0 
+          && sAttrData.nFileSizeLow==0 ){
+        attr = INVALID_FILE_ATTRIBUTES;
+      }else{
+        attr = sAttrData.dwFileAttributes;
+      }
+    }else{
+      if( GetLastError()!=ERROR_FILE_NOT_FOUND ){
+        free(zConverted);
+        return SQLITE_IOERR_ACCESS;
+      }else{
+        attr = INVALID_FILE_ATTRIBUTES;
+      }
+    }
 /* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
 ** Since the ASCII version of these Windows API do not exist for WINCE,
 ** it's important to not reference them for WINCE builds.
@@ -31236,7 +31293,6 @@ SQLITE_API int sqlite3_os_init(void){
     winSleep,            /* xSleep */
     winCurrentTime,      /* xCurrentTime */
     winGetLastError,     /* xGetLastError */
-    0,                   /* xRename */
     winCurrentTimeInt64, /* xCurrentTimeInt64 */
   };
 
@@ -33506,13 +33562,14 @@ SQLITE_PRIVATE int sqlite3RowSetTest(RowSet *pRowSet, u8 iBatch, sqlite3_int64 i
 # define sqlite3WalRead(v,w,x,y,z)             0
 # define sqlite3WalDbsize(y,z)
 # define sqlite3WalBeginWriteTransaction(y)    0
-# define sqlite3WalEndWRiteTransaction(x)      0
+# define sqlite3WalEndWriteTransaction(x)      0
 # define sqlite3WalUndo(x,y,z)                 0
 # define sqlite3WalSavepoint(y,z)
 # define sqlite3WalSavepointUndo(y,z)          0
 # define sqlite3WalFrames(u,v,w,x,y,z)         0
 # define sqlite3WalCheckpoint(u,v,w,x)         0
 # define sqlite3WalCallback(z)                 0
+# define sqlite3WalExclusiveMode(y,z)          0
 #else
 
 #define WAL_SAVEPOINT_NDATA 4
@@ -33786,7 +33843,9 @@ struct PagerSavepoint {
   Bitvec *pInSavepoint;        /* Set of pages in this savepoint */
   Pgno nOrig;                  /* Original number of pages in file */
   Pgno iSubRec;                /* Index of first record in sub-journal */
+#ifndef SQLITE_OMIT_WAL
   u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
+#endif
 };
 
 /*
@@ -33970,6 +34029,7 @@ struct Pager {
   sqlite3_backup *pBackup;    /* Pointer to list of ongoing backup processes */
 #ifndef SQLITE_OMIT_WAL
   Wal *pWal;                  /* Write-ahead log used by "journal_mode=wal" */
+  char *zWal;                 /* File name for write-ahead log */
 #endif
 };
 
@@ -35081,6 +35141,21 @@ static u32 pager_cksum(Pager *pPager, const u8 *aData){
 }
 
 /*
+** 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.
 ** The page begins at offset *pOffset into the file. The *pOffset
@@ -35172,12 +35247,21 @@ 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.
@@ -35978,43 +36062,40 @@ static int pagerBeginReadTransaction(Pager *pPager){
 
 /*
 ** Check if the *-wal file that corresponds to the database opened by pPager
-** exists. Assuming no error occurs, set *pExists to 1 if the file exists,
-** or 0 otherwise and return SQLITE_OK. If an IO or OOM error occurs, return
-** an SQLite error code.
-*/
-static int pagerHasWAL(Pager *pPager, int *pExists){
-  int rc;                         /* Return code */
-  char *zWal;                     /* Name of the WAL file */
-
-  assert( !pPager->tempFile );
-  zWal = sqlite3_mprintf("%s-wal", pPager->zFilename);
-  if( !zWal ){
-    rc = SQLITE_NOMEM;
-  }else{
-    rc = sqlite3OsAccess(pPager->pVfs, zWal, SQLITE_ACCESS_EXISTS, pExists);
-    sqlite3_free(zWal);
-  }
-  return rc;
-}
-
-/*
-** Check if the *-wal file that corresponds to the database opened by pPager
-** exists. If it does, open the pager in WAL mode. Otherwise, if no error
-** occurs, make sure Pager.journalMode is not set to PAGER_JOURNALMODE_WAL.
-** If an IO or OOM error occurs, return an SQLite error code.
+** exists if the database is not empy, or verify that the *-wal file does
+** not exist (by deleting it) if the database file is empty.
+**
+** If the database is not empty and the *-wal file exists, open the pager
+** in WAL mode.  If the database is empty or if no *-wal file exists and
+** if no error occurs, make sure Pager.journalMode is not set to
+** PAGER_JOURNALMODE_WAL.
+**
+** Return SQLITE_OK or an error code.
 **
 ** If the WAL file is opened, also open a snapshot (read transaction).
 **
 ** The caller must hold a SHARED lock on the database file to call this
 ** function. Because an EXCLUSIVE lock on the db file is required to delete 
-** a WAL, this ensures there is no race condition between the xAccess() 
-** below and an xDelete() being executed by some other connection.
+** a WAL on a none-empty database, this ensures there is no race condition 
+** between the xAccess() below and an xDelete() being executed by some 
+** other connection.
 */
 static int pagerOpenWalIfPresent(Pager *pPager){
   int rc = SQLITE_OK;
   if( !pPager->tempFile ){
     int isWal;                    /* True if WAL file exists */
-    rc = pagerHasWAL(pPager, &isWal);
+    int nPage;                    /* Size of the database file */
+    assert( pPager->state>=SHARED_LOCK );
+    rc = sqlite3PagerPagecount(pPager, &nPage);
+    if( rc ) return rc;
+    if( nPage==0 ){
+      rc = sqlite3OsDelete(pPager->pVfs, pPager->zWal, 0);
+      isWal = 0;
+    }else{
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &isWal
+      );
+    }
     if( rc==SQLITE_OK ){
       if( isWal ){
         pager_reset(pPager);
@@ -36288,21 +36369,6 @@ SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(
 }
 
 /*
-** 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.
 **
@@ -36388,7 +36454,7 @@ SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
   }
   if( pPager->state!=PAGER_UNLOCK ){
     sqlite3PagerPagecount(pPager, &nPage);
-    assert( pPager->mxPgno>=nPage );
+    assert( (int)pPager->mxPgno>=nPage );
   }
   return pPager->mxPgno;
 }
@@ -36441,15 +36507,6 @@ SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned cha
   ** 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))
@@ -36893,13 +36950,9 @@ static int syncJournal(Pager *pPager){
 ** occurs, an IO error code is returned. Or, if the EXCLUSIVE lock cannot
 ** be obtained, SQLITE_BUSY is returned.
 */
-static int pager_write_pagelist(PgHdr *pList){
-  Pager *pPager;                       /* Pager object */
+static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
   int rc;                              /* Return code */
 
-  if( NEVER(pList==0) ) return SQLITE_OK;
-  pPager = pList->pPager;
-
   /* At this point there may be either a RESERVED or EXCLUSIVE lock on the
   ** database file. If there is already an EXCLUSIVE lock, the following
   ** call is a no-op.
@@ -36916,7 +36969,7 @@ static int pager_write_pagelist(PgHdr *pList){
   ** EXCLUSIVE, it means the database file has been changed and any rollback
   ** will require a journal playback.
   */
-  assert( !pagerUseWal(pList->pPager) );
+  assert( !pagerUseWal(pPager) );
   assert( pPager->state>=PAGER_RESERVED );
   rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
 
@@ -37161,7 +37214,7 @@ static int pagerStress(void *p, PgHdr *pPg){
   
     /* Write the contents of the page out to the database file. */
     if( rc==SQLITE_OK ){
-      rc = pager_write_pagelist(pPg);
+      rc = pager_write_pagelist(pPager, pPg);
     }
   }
 
@@ -37301,6 +37354,9 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
     journalFileSize * 2 +          /* The two journal files */ 
     nPathname + 1 +                /* zFilename */
     nPathname + 8 + 1              /* zJournal */
+#ifndef SQLITE_OMIT_WAL
+    + nPathname + 4 + 1              /* zWal */
+#endif
   );
   assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
   if( !pPtr ){
@@ -37321,7 +37377,16 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
     memcpy(pPager->zFilename, zPathname, nPathname);
     memcpy(pPager->zJournal, zPathname, nPathname);
     memcpy(&pPager->zJournal[nPathname], "-journal", 8);
-    if( pPager->zFilename[0]==0 ) pPager->zJournal[0] = 0;
+    if( pPager->zFilename[0]==0 ){
+      pPager->zJournal[0] = 0;
+    }
+#ifndef SQLITE_OMIT_WAL
+    else{
+      pPager->zWal = &pPager->zJournal[nPathname+8+1];
+      memcpy(pPager->zWal, zPathname, nPathname);
+      memcpy(&pPager->zWal[nPathname], "-wal", 4);
+    }
+#endif
     sqlite3_free(zPathname);
   }
   pPager->pVfs = pVfs;
@@ -38197,30 +38262,19 @@ SQLITE_PRIVATE int sqlite3PagerBegin(Pager *pPager, int exFlag, int subjInMemory
     ** we might save the work of creating a file if the transaction
     ** ends up being a no-op.
     */
-  }else if( isOpen(pPager->jfd) && pPager->journalOff==0 ){
-    /* This happens when the pager was in exclusive-access mode the last
-    ** time a (read or write) transaction was successfully concluded
-    ** by this connection. Instead of deleting the journal file it was 
-    ** kept open and either was truncated to 0 bytes or its header was
-    ** overwritten with zeros.
-    */
-    assert( pagerUseWal(pPager)==0 );
-    assert( pPager->nRec==0 );
-    assert( pPager->dbOrigSize==0 );
-    assert( pPager->pInJournal==0 );
-    rc = pager_open_journal(pPager);
+
+    if( rc!=SQLITE_OK ){
+      assert( !pPager->dbModified );
+      /* Ignore any IO error that occurs within pager_end_transaction(). The
+      ** purpose of this call is to reset the internal state of the pager
+      ** sub-system. It doesn't matter if the journal-file is not properly
+      ** finalized at this point (since it is not a valid journal file anyway).
+      */
+      pager_end_transaction(pPager, 0);
+    }
   }
 
   PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
-  if( rc!=SQLITE_OK ){
-    assert( !pPager->dbModified );
-    /* Ignore any IO error that occurs within pager_end_transaction(). The
-    ** purpose of this call is to reset the internal state of the pager
-    ** sub-system. It doesn't matter if the journal-file is not properly
-    ** finalized at this point (since it is not a valid journal file anyway).
-    */
-    pager_end_transaction(pPager, 0);
-  }
   return rc;
 }
 
@@ -38271,10 +38325,7 @@ static int pager_write(PgHdr *pPg){
     ** which means they have acquired the necessary locks but the rollback
     ** journal might not yet be open.
     */
-    rc = sqlite3PagerBegin(pPager, 0, pPager->subjInMemory);
-    if( rc!=SQLITE_OK ){
-      return rc;
-    }
+    assert( pPager->state>=RESERVED_LOCK );
     if( pPager->pInJournal==0
      && pPager->journalMode!=PAGER_JOURNALMODE_OFF 
      && !pagerUseWal(pPager)
@@ -38715,7 +38766,10 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
       */
   #ifdef SQLITE_ENABLE_ATOMIC_WRITE
       PgHdr *pPg;
-      assert( isOpen(pPager->jfd) || pPager->journalMode==PAGER_JOURNALMODE_OFF );
+      assert( isOpen(pPager->jfd) 
+           || pPager->journalMode==PAGER_JOURNALMODE_OFF 
+           || pPager->journalMode==PAGER_JOURNALMODE_WAL 
+      );
       if( !zMaster && isOpen(pPager->jfd) 
        && pPager->journalOff==jrnlBufferSize(pPager) 
        && pPager->dbSize>=pPager->dbFileSize
@@ -38789,7 +38843,7 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseOne(
       if( rc!=SQLITE_OK ) goto commit_phase_one_exit;
   
       /* Write all dirty pages to the database file. */
-      rc = pager_write_pagelist(sqlite3PcacheDirtyList(pPager->pPCache));
+      rc = pager_write_pagelist(pPager,sqlite3PcacheDirtyList(pPager->pPCache));
       if( rc!=SQLITE_OK ){
         assert( rc!=SQLITE_IOERR_BLOCKED );
         goto commit_phase_one_exit;
@@ -38849,7 +38903,7 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
   ** fails - make it so that we never reach this point if we do not hold
   ** all necessary locks.
   */
-  if( pPager->state<PAGER_RESERVED ) return SQLITE_ERROR;
+  if( NEVER(pPager->state<PAGER_RESERVED) ) return SQLITE_ERROR;
 
   /* An optimization. If the database was not actually modified during
   ** this transaction, the pager is running in exclusive-mode and is
@@ -38865,7 +38919,7 @@ SQLITE_PRIVATE int sqlite3PagerCommitPhaseTwo(Pager *pPager){
   if( pPager->dbModified==0 && pPager->exclusiveMode 
    && pPager->journalMode==PAGER_JOURNALMODE_PERSIST
   ){
-    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
+    assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) || !pPager->journalOff );
     return SQLITE_OK;
   }
 
@@ -39199,7 +39253,7 @@ SQLITE_PRIVATE int sqlite3PagerNosync(Pager *pPager){
 /*
 ** Set or retrieve the codec for this pager
 */
-static void sqlite3PagerSetCodec(
+SQLITE_PRIVATE void sqlite3PagerSetCodec(
   Pager *pPager,
   void *(*xCodec)(void*,void*,Pgno,int),
   void (*xCodecSizeChng)(void*,int,int),
@@ -39213,7 +39267,7 @@ static void sqlite3PagerSetCodec(
   pPager->pCodec = pCodec;
   pagerReportSize(pPager);
 }
-static void *sqlite3PagerGetCodec(Pager *pPager){
+SQLITE_PRIVATE void *sqlite3PagerGetCodec(Pager *pPager){
   return pPager->pCodec;
 }
 #endif
@@ -39537,7 +39591,7 @@ SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager *pPager){
 */
 SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager *pPager){
   if( pPager->dbModified ) return 0;
-  if( isOpen(pPager->jfd) && pPager->journalOff>0 ) return 0;
+  if( NEVER(isOpen(pPager->jfd) && pPager->journalOff>0) ) return 0;
   return 1;
 }
 
@@ -39594,25 +39648,37 @@ SQLITE_PRIVATE int sqlite3PagerWalSupported(Pager *pPager){
 }
 
 /*
-** Open a connection to the write-ahead log file for pager pPager. If
-** the log connection is already open, this function is a no-op.
-**
 ** The caller must be holding a SHARED lock on the database file to call
 ** this function.
+**
+** If the pager passed as the first argument is open on a real database
+** file (not a temp file or an in-memory database), and the WAL file
+** is not already open, make an attempt to open it now. If successful,
+** return SQLITE_OK. If an error occurs or the VFS used by the pager does 
+** not support the xShmXXX() methods, return an error code. *pisOpen is
+** not modified in either case.
+**
+** If the pager is open on a temp-file (or in-memory database), or if
+** the WAL file is already open, set *pisOpen to 1 and return SQLITE_OK
+** without doing anything.
 */
-SQLITE_PRIVATE int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen){
+SQLITE_PRIVATE int sqlite3PagerOpenWal(
+  Pager *pPager,                  /* Pager object */
+  int *pisOpen                    /* OUT: Set to true if call is a no-op */
+){
   int rc = SQLITE_OK;             /* Return code */
 
   assert( pPager->state>=PAGER_SHARED );
-  if( !pPager->pWal ){
+  assert( (pisOpen==0 && !pPager->tempFile && !pPager->pWal) || *pisOpen==0 );
+
+  if( !pPager->tempFile && !pPager->pWal ){
     if( !sqlite3PagerWalSupported(pPager) ) return SQLITE_CANTOPEN;
 
     /* Open the connection to the log file. If this operation fails, 
     ** (e.g. due to malloc() failure), unlock the database file and 
     ** return an error code.
     */
-    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
-                        pPager->zFilename, &pPager->pWal);
+    rc = sqlite3WalOpen(pPager->pVfs, pPager->fd, pPager->zWal, &pPager->pWal);
     if( rc==SQLITE_OK ){
       pPager->journalMode = PAGER_JOURNALMODE_WAL;
     }
@@ -39645,11 +39711,13 @@ SQLITE_PRIVATE int sqlite3PagerCloseWal(Pager *pPager){
     int logexists = 0;
     rc = sqlite3OsLock(pPager->fd, SQLITE_LOCK_SHARED);
     if( rc==SQLITE_OK ){
-      rc = pagerHasWAL(pPager, &logexists);
+      rc = sqlite3OsAccess(
+          pPager->pVfs, pPager->zWal, SQLITE_ACCESS_EXISTS, &logexists
+      );
     }
     if( rc==SQLITE_OK && logexists ){
       rc = sqlite3WalOpen(pPager->pVfs, pPager->fd,
-                          pPager->zFilename, &pPager->pWal);
+                          pPager->zWal, &pPager->pWal);
     }
   }
     
@@ -40091,7 +40159,7 @@ struct WalCkptInfo {
 ** is to the start of the write-ahead log frame-header.
 */
 #define walFrameOffset(iFrame, szPage) (                               \
-  WAL_HDRSIZE + ((iFrame)-1)*((szPage)+WAL_FRAME_HDRSIZE)        \
+  WAL_HDRSIZE + ((iFrame)-1)*(i64)((szPage)+WAL_FRAME_HDRSIZE)         \
 )
 
 /*
@@ -40112,7 +40180,7 @@ struct Wal {
   u8 writeLock;              /* True if in a write transaction */
   u8 ckptLock;               /* True if holding a checkpoint lock */
   WalIndexHdr hdr;           /* Wal-index header for current transaction */
-  char *zWalName;            /* Name of WAL file */
+  const char *zWalName;      /* Name of WAL file */
   u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
 #ifdef SQLITE_DEBUG
   u8 lockError;              /* True if a locking error has occurred */
@@ -40192,12 +40260,12 @@ static int walIndexPage(Wal *pWal, int iPage, volatile u32 **ppPage){
   if( pWal->nWiData<=iPage ){
     int nByte = sizeof(u32 *)*(iPage+1);
     volatile u32 **apNew;
-    apNew = (volatile u32 **)sqlite3_realloc(pWal->apWiData, nByte);
+    apNew = (volatile u32 **)sqlite3_realloc((void *)pWal->apWiData, nByte);
     if( !apNew ){
       *ppPage = 0;
       return SQLITE_NOMEM;
     }
-    memset(&apNew[pWal->nWiData], 0, sizeof(u32 *)*(iPage+1-pWal->nWiData));
+    memset((void *)&apNew[pWal->nWiData], 0, sizeof(u32 *)*(iPage+1-pWal->nWiData));
     pWal->apWiData = apNew;
     pWal->nWiData = iPage+1;
   }
@@ -40432,7 +40500,7 @@ static int walLockShared(Wal *pWal, int lockIdx){
                         SQLITE_SHM_LOCK | SQLITE_SHM_SHARED);
   WALTRACE(("WAL%p: acquire SHARED-%s %s\n", pWal,
             walLockName(lockIdx), rc ? "failed" : "ok"));
-  VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
   return rc;
 }
 static void walUnlockShared(Wal *pWal, int lockIdx){
@@ -40448,7 +40516,7 @@ static int walLockExclusive(Wal *pWal, int lockIdx, int n){
                         SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE);
   WALTRACE(("WAL%p: acquire EXCLUSIVE-%s cnt=%d %s\n", pWal,
             walLockName(lockIdx), n, rc ? "failed" : "ok"));
-  VVA_ONLY( pWal->lockError = (rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
+  VVA_ONLY( pWal->lockError = (u8)(rc!=SQLITE_OK && rc!=SQLITE_BUSY); )
   return rc;
 }
 static void walUnlockExclusive(Wal *pWal, int lockIdx, int n){
@@ -40596,7 +40664,7 @@ static void walCleanupHash(Wal *pWal){
   /* Zero the entries in the aPgno array that correspond to frames with
   ** frame numbers greater than pWal->hdr.mxFrame. 
   */
-  nByte = ((char *)aHash - (char *)&aPgno[iLimit+1]);
+  nByte = (int)((char *)aHash - (char *)&aPgno[iLimit+1]);
   memset((void *)&aPgno[iLimit+1], 0, nByte);
 
 #ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
@@ -40644,7 +40712,7 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
     ** entire hash table and aPgno[] array before proceding. 
     */
     if( idx==1 ){
-      int nByte = (u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1];
+      int nByte = (int)((u8 *)&aHash[HASHTABLE_NSLOT] - (u8 *)&aPgno[1]);
       memset((void*)&aPgno[1], 0, nByte);
     }
 
@@ -40664,7 +40732,7 @@ static int walIndexAppend(Wal *pWal, u32 iFrame, u32 iPage){
       assert( nCollide++ < idx );
     }
     aPgno[idx] = iPage;
-    aHash[iKey] = idx;
+    aHash[iKey] = (ht_slot)idx;
 
 #ifdef SQLITE_ENABLE_EXPENSIVE_ASSERT
     /* Verify that the number of entries in the hash table exactly equals
@@ -40772,8 +40840,8 @@ static int walIndexRecover(Wal *pWal){
     ){
       goto finished;
     }
-    pWal->hdr.bigEndCksum = (magic&0x00000001);
-    pWal->szPage = szPage;
+    pWal->hdr.bigEndCksum = (u8)(magic&0x00000001);
+    pWal->szPage = (u16)szPage;
     pWal->nCkpt = sqlite3Get4byte(&aBuf[12]);
     memcpy(&pWal->hdr.aSalt, &aBuf[16], 8);
 
@@ -40823,7 +40891,7 @@ static int walIndexRecover(Wal *pWal){
       if( nTruncate ){
         pWal->hdr.mxFrame = iFrame;
         pWal->hdr.nPage = nTruncate;
-        pWal->hdr.szPage = szPage;
+        pWal->hdr.szPage = (u16)szPage;
         aFrameCksum[0] = pWal->hdr.aFrameCksum[0];
         aFrameCksum[1] = pWal->hdr.aFrameCksum[1];
       }
@@ -40867,8 +40935,9 @@ static void walIndexClose(Wal *pWal, int isDelete){
 }
 
 /* 
-** Open a connection to the WAL file associated with database zDbName.
-** The database file must already be opened on connection pDbFd.
+** Open a connection to the WAL file zWalName. The database file must 
+** already be opened on connection pDbFd. The buffer that zWalName points
+** to must remain valid for the lifetime of the returned Wal* handle.
 **
 ** A SHARED lock should be held on the database file when this function
 ** is called. The purpose of this SHARED lock is to prevent any other
@@ -40883,16 +40952,14 @@ static void walIndexClose(Wal *pWal, int isDelete){
 SQLITE_PRIVATE int sqlite3WalOpen(
   sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
   sqlite3_file *pDbFd,            /* The open database file */
-  const char *zDbName,            /* Name of the database file */
+  const char *zWalName,           /* Name of the WAL file */
   Wal **ppWal                     /* OUT: Allocated Wal handle */
 ){
   int rc;                         /* Return Code */
   Wal *pRet;                      /* Object to allocate and return */
   int flags;                      /* Flags passed to OsOpen() */
-  char *zWal;                     /* Name of write-ahead log file */
-  int nWal;                       /* Length of zWal in bytes */
 
-  assert( zDbName && zDbName[0] );
+  assert( zWalName && zWalName[0] );
   assert( pDbFd );
 
   /* In the amalgamation, the os_unix.c and os_win.c source files come before
@@ -40909,8 +40976,7 @@ SQLITE_PRIVATE int sqlite3WalOpen(
 
   /* Allocate an instance of struct Wal to return. */
   *ppWal = 0;
-  nWal = sqlite3Strlen30(zDbName) + 5;
-  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile + nWal);
+  pRet = (Wal*)sqlite3MallocZero(sizeof(Wal) + pVfs->szOsFile);
   if( !pRet ){
     return SQLITE_NOMEM;
   }
@@ -40920,15 +40986,14 @@ SQLITE_PRIVATE int sqlite3WalOpen(
   pRet->pDbFd = pDbFd;
   pRet->readLock = -1;
   sqlite3_randomness(8, &pRet->hdr.aSalt);
-  pRet->zWalName = zWal = pVfs->szOsFile + (char*)pRet->pWalFd;
-  sqlite3_snprintf(nWal, zWal, "%s-wal", zDbName);
+  pRet->zWalName = zWalName;
   rc = sqlite3OsShmOpen(pDbFd);
 
   /* Open file handle on the write-ahead log file. */
   if( rc==SQLITE_OK ){
     pRet->isWIndexOpen = 1;
     flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MAIN_JOURNAL);
-    rc = sqlite3OsOpen(pVfs, zWal, pRet->pWalFd, flags, &flags);
+    rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
   }
 
   if( rc!=SQLITE_OK ){
@@ -41151,12 +41216,12 @@ static int walIteratorInit(Wal *pWal, WalIterator **pp){
       ht_slot *aIndex;            /* Sorted index for this segment */
 
       aPgno++;
-      nEntry = ((i+1)==nSegment)?(int)(iLast-iZero):(u32 *)aHash-(u32 *)aPgno;
+      nEntry = (int)(((i+1)==nSegment)?(int)(iLast-iZero):(u32 *)aHash-(u32 *)aPgno);
       aIndex = &((ht_slot *)&p->aSegment[p->nSegment])[iZero];
       iZero++;
   
       for(j=0; j<nEntry; j++){
-        aIndex[j] = j;
+        aIndex[j] = (ht_slot)j;
       }
       walMergesort((u32 *)aPgno, aTmp, aIndex, &nEntry);
       p->aSegment[i].iZero = iZero;
@@ -41270,20 +41335,25 @@ static int walCheckpoint(
 
     /* Iterate through the contents of the WAL, copying data to the db file. */
     while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
+      i64 iOffset;
       assert( walFramePgno(pWal, iFrame)==iDbpage );
       if( iFrame<=nBackfill || iFrame>mxSafeFrame ) continue;
-      rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, 
-          walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE
-      );
+      iOffset = walFrameOffset(iFrame, szPage) + WAL_FRAME_HDRSIZE;
+      /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL file */
+      rc = sqlite3OsRead(pWal->pWalFd, zBuf, szPage, iOffset);
       if( rc!=SQLITE_OK ) break;
-      rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, (iDbpage-1)*szPage);
+      iOffset = (iDbpage-1)*(i64)szPage;
+      testcase( IS_BIG_INT(iOffset) );
+      rc = sqlite3OsWrite(pWal->pDbFd, zBuf, szPage, iOffset);
       if( rc!=SQLITE_OK ) break;
     }
 
     /* If work was actually accomplished... */
     if( rc==SQLITE_OK ){
       if( mxSafeFrame==walIndexHdr(pWal)->mxFrame ){
-        rc = sqlite3OsTruncate(pWal->pDbFd, ((i64)pWal->hdr.nPage*(i64)szPage));
+        i64 szDb = pWal->hdr.nPage*(i64)szPage;
+        testcase( IS_BIG_INT(szDb) );
+        rc = sqlite3OsTruncate(pWal->pDbFd, szDb);
         if( rc==SQLITE_OK && sync_flags ){
           rc = sqlite3OsSync(pWal->pDbFd, sync_flags);
         }
@@ -41343,7 +41413,7 @@ SQLITE_PRIVATE int sqlite3WalClose(
       sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
     }
     WALTRACE(("WAL%p: closed\n", pWal));
-    sqlite3_free(pWal->apWiData);
+    sqlite3_free((void *)pWal->apWiData);
     sqlite3_free(pWal);
   }
   return rc;
@@ -41679,7 +41749,7 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){
       return WAL_RETRY;
     }else{
       assert( mxReadMark<=pWal->hdr.mxFrame );
-      pWal->readLock = mxI;
+      pWal->readLock = (i16)mxI;
     }
   }
   return rc;
@@ -41821,6 +41891,7 @@ SQLITE_PRIVATE int sqlite3WalRead(
   if( iRead ){
     i64 iOffset = walFrameOffset(iRead, pWal->hdr.szPage) + WAL_FRAME_HDRSIZE;
     *pInWal = 1;
+    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
     return sqlite3OsRead(pWal->pWalFd, pOut, nOut, iOffset);
   }
 
@@ -42092,7 +42163,7 @@ SQLITE_PRIVATE int sqlite3WalFrames(
     sqlite3Put4byte(&aWalHdr[24], aCksum[0]);
     sqlite3Put4byte(&aWalHdr[28], aCksum[1]);
     
-    pWal->szPage = szPage;
+    pWal->szPage = (u16)szPage;
     pWal->hdr.bigEndCksum = SQLITE_BIGENDIAN;
     pWal->hdr.aFrameCksum[0] = aCksum[0];
     pWal->hdr.aFrameCksum[1] = aCksum[1];
@@ -42111,8 +42182,8 @@ SQLITE_PRIVATE int sqlite3WalFrames(
     i64 iOffset;                  /* Write offset in log file */
     void *pData;
    
-   
     iOffset = walFrameOffset(++iFrame, szPage);
+    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
     
     /* Populate and write the frame header */
     nDbsize = (isCommit && p->pDirty==0) ? nTruncate : 0;
@@ -42152,6 +42223,7 @@ SQLITE_PRIVATE int sqlite3WalFrames(
       pData = pLast->pData;
 #endif
       walEncodeFrame(pWal, pLast->pgno, nTruncate, pData, aFrame);
+      /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
       rc = sqlite3OsWrite(pWal->pWalFd, aFrame, sizeof(aFrame), iOffset);
       if( rc!=SQLITE_OK ){
         return rc;
@@ -42186,7 +42258,7 @@ SQLITE_PRIVATE int sqlite3WalFrames(
 
   if( rc==SQLITE_OK ){
     /* Update the private copy of the header. */
-    pWal->hdr.szPage = szPage;
+    pWal->hdr.szPage = (u16)szPage;
     pWal->hdr.mxFrame = iFrame;
     if( isCommit ){
       pWal->hdr.iChange++;
@@ -44923,16 +44995,20 @@ static int getAndInitPage(
   int rc;
   assert( sqlite3_mutex_held(pBt->mutex) );
 
-  if( pgno<=0 || pgno>btreePagecount(pBt) ){
-    return SQLITE_CORRUPT_BKPT;
-  }
-  rc = btreeGetPage(pBt, pgno, ppPage, 0);
-  if( rc==SQLITE_OK ){
-    rc = btreeInitPage(*ppPage);
-    if( rc!=SQLITE_OK ){
-      releasePage(*ppPage);
+  if( pgno>btreePagecount(pBt) ){
+    rc = SQLITE_CORRUPT_BKPT;
+  }else{
+    rc = btreeGetPage(pBt, pgno, ppPage, 0);
+    if( rc==SQLITE_OK ){
+      rc = btreeInitPage(*ppPage);
+      if( rc!=SQLITE_OK ){
+        releasePage(*ppPage);
+      }
     }
   }
+
+  testcase( pgno==0 );
+  assert( pgno!=0 || rc==SQLITE_CORRUPT );
   return rc;
 }
 
@@ -45859,7 +45935,7 @@ SQLITE_PRIVATE int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
   rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
   if( SQLITE_OK!=rc ) goto trans_begun;
 
-  pBt->initiallyEmpty = pBt->nPage==0;
+  pBt->initiallyEmpty = (u8)(pBt->nPage==0);
   do {
     /* Call lockBtree() until either pBt->pPage1 is populated or
     ** lockBtree() returns something other than SQLITE_OK. lockBtree()
@@ -47582,7 +47658,6 @@ SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
     if( pCur->eState==CURSOR_INVALID ){
       assert( pCur->apPage[pCur->iPage]->nCell==0 );
       *pRes = 1;
-      rc = SQLITE_OK;
     }else{
       assert( pCur->apPage[pCur->iPage]->nCell>0 );
       *pRes = 0;
@@ -51347,7 +51422,7 @@ SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
   /* If setting the version fields to 1, do not automatically open the
   ** WAL connection, even if the version fields are currently set to 2.
   */
-  pBt->doNotUseWAL = (iVersion==1);
+  pBt->doNotUseWAL = (u8)(iVersion==1);
 
   rc = sqlite3BtreeBeginTrans(pBtree, 0);
   if( rc==SQLITE_OK ){
@@ -51839,6 +51914,9 @@ SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage){
       assert( rc2==SQLITE_OK );
     }
   
+    if( rc==SQLITE_IOERR_NOMEM ){
+      rc = SQLITE_NOMEM;
+    }
     p->rc = rc;
   }
   if( p->pDestDb ){
@@ -53961,7 +54039,9 @@ SQLITE_PRIVATE void sqlite3VdbeNoopComment(Vdbe *p, const char *zFormat, ...){
 ** check the value of p->nOp-1 before continuing.
 */
 SQLITE_PRIVATE VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
-  static const VdbeOp dummy;
+  /* C89 specifies that the constant "dummy" will be initialized to all
+  ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
+  static const VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
   assert( p->magic==VDBE_MAGIC_INIT );
   if( addr<0 ){
 #ifdef SQLITE_OMIT_TRACE
@@ -62392,14 +62472,13 @@ case OP_Rewind: {        /* jump */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   u.bl.pC = p->apCsr[pOp->p1];
   assert( u.bl.pC!=0 );
+  u.bl.res = 1;
   if( (u.bl.pCrsr = u.bl.pC->pCursor)!=0 ){
     rc = sqlite3BtreeFirst(u.bl.pCrsr, &u.bl.res);
     u.bl.pC->atFirst = u.bl.res==0 ?1:0;
     u.bl.pC->deferredMoveto = 0;
     u.bl.pC->cacheStatus = CACHE_STALE;
     u.bl.pC->rowidIsValid = 0;
-  }else{
-    u.bl.res = 1;
   }
   u.bl.pC->nullRow = (u8)u.bl.res;
   assert( pOp->p2>0 && pOp->p2<p->nOp );
@@ -63443,6 +63522,7 @@ case OP_Checkpoint: {
 };  
 #endif
 
+#ifndef SQLITE_OMIT_PRAGMA
 /* Opcode: JournalMode P1 P2 P3 * P5
 **
 ** Change the journal mode of database P1 to P3. P3 must be one of the
@@ -63569,7 +63649,8 @@ case OP_JournalMode: {    /* out2-prerelease */
   pOut->enc = SQLITE_UTF8;
   sqlite3VdbeChangeEncoding(pOut, encoding);
   break;
-};  
+};
+#endif /* SQLITE_OMIT_PRAGMA */
 
 #if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
 /* Opcode: Vacuum * * * * *
@@ -64753,7 +64834,12 @@ static struct sqlite3_io_methods JournalFileMethods = {
   0,             /* xCheckReservedLock */
   0,             /* xFileControl */
   0,             /* xSectorSize */
-  0              /* xDeviceCharacteristics */
+  0,             /* xDeviceCharacteristics */
+  0,             /* xShmOpen */
+  0,             /* xShmLock */
+  0,             /* xShmMap */
+  0,             /* xShmBarrier */
+  0              /* xShmClose */
 };
 
 /* 
@@ -83531,6 +83617,10 @@ SQLITE_PRIVATE void sqlite3Pragma(
   if( sqlite3StrICmp(zLeft,"journal_mode")==0 ){
     int eMode;                    /* One of the PAGER_JOURNALMODE_XXX symbols */
 
+    if( sqlite3ReadSchema(pParse) ){
+      goto pragma_out;
+    }
+
     sqlite3VdbeSetNumCols(v, 1);
     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "journal_mode", SQLITE_STATIC);
 
@@ -83539,7 +83629,7 @@ SQLITE_PRIVATE void sqlite3Pragma(
     }else{
       const char *zMode;
       int n = sqlite3Strlen30(zRight);
-      for(eMode=0; (zMode = sqlite3JournalModename(eMode)); eMode++){
+      for(eMode=0; (zMode = sqlite3JournalModename(eMode))!=0; eMode++){
         if( sqlite3StrNICmp(zRight, zMode, n)==0 ) break;
       }
       if( !zMode ){
@@ -84594,12 +84684,15 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
     */
     int rc;
     sqlite3_stmt *pStmt;
+    TESTONLY(int rcp);            /* Return code from sqlite3_prepare() */
 
     assert( db->init.busy );
     db->init.iDb = iDb;
     db->init.newTnum = atoi(argv[1]);
     db->init.orphanTrigger = 0;
-    rc = sqlite3_prepare(db, argv[2], -1, &pStmt, 0);
+    TESTONLY(rcp = ) sqlite3_prepare(db, argv[2], -1, &pStmt, 0);
+    rc = db->errCode;
+    assert( (rc&0xFF)==(rcp&0xFF) );
     db->init.iDb = 0;
     if( SQLITE_OK!=rc ){
       if( db->init.orphanTrigger ){
@@ -84608,7 +84701,7 @@ SQLITE_PRIVATE int sqlite3InitCallback(void *pInit, int argc, char **argv, char
         pData->rc = rc;
         if( rc==SQLITE_NOMEM ){
           db->mallocFailed = 1;
-        }else if( rc!=SQLITE_INTERRUPT && rc!=SQLITE_LOCKED ){
+        }else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){
           corruptSchema(pData, argv[0], sqlite3_errmsg(db));
         }
       }
@@ -94775,7 +94868,7 @@ static void constructAutomaticIndex(
       }
     }
   }
-  assert( n==pLevel->plan.nEq );
+  assert( (u32)n==pLevel->plan.nEq );
 
   /* Add additional columns needed to make the automatic index into
   ** a covering index */
@@ -96369,7 +96462,7 @@ static Bitmask codeOneLoopStart(
     ** a forward order scan on a descending index, interchange the 
     ** start and end terms (pRangeStart and pRangeEnd).
     */
-    if( bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
+    if( nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
       SWAP(WhereTerm *, pRangeEnd, pRangeStart);
     }
 
@@ -104069,7 +104162,6 @@ SQLITE_API int sqlite3_collation_needed16(
 }
 #endif /* SQLITE_OMIT_UTF16 */
 
-#ifndef SQLITE_OMIT_GLOBALRECOVER
 #ifndef SQLITE_OMIT_DEPRECATED
 /*
 ** This function is now an anachronism. It used to be used to recover from a
@@ -104079,7 +104171,6 @@ SQLITE_API int sqlite3_global_recover(void){
   return SQLITE_OK;
 }
 #endif
-#endif
 
 /*
 ** Test to see whether or not the database connection is in autocommit
@@ -106054,6 +106145,9 @@ static int fts3CreateTables(Fts3Table *p){
 ** An sqlite3_exec() callback for fts3TableExists.
 */
 static int fts3TableExistsCallback(void *pArg, int n, char **pp1, char **pp2){
+  UNUSED_PARAMETER(n);
+  UNUSED_PARAMETER(pp1);
+  UNUSED_PARAMETER(pp2);
   *(int*)pArg = 1;
   return 1;
 }
@@ -106079,7 +106173,7 @@ static void fts3TableExists(
   );    
   rc = sqlite3_exec(db, zSql, fts3TableExistsCallback, &res, 0);
   sqlite3_free(zSql);
-  *pResult = res & 0xff;
+  *pResult = (u8)(res & 0xff);
   if( rc!=SQLITE_ABORT ) *pRc = rc;
 }
 
diff --git a/dist/sqlite3.h b/dist/sqlite3.h
index 9ad6e39..9268b20 100644
--- a/dist/sqlite3.h
+++ b/dist/sqlite3.h
@@ -109,7 +109,7 @@ extern "C" {
 */
 #define SQLITE_VERSION        "3.7.0"
 #define SQLITE_VERSION_NUMBER 3007000
-#define SQLITE_SOURCE_ID      "2010-06-28 10:15:20 4932f22848b3d15a2b6dc5fa2cd69ce19182e2a4"
+#define SQLITE_SOURCE_ID      "2010-07-07 14:45:41 8eefc287265443ec043bdab629597e79c9d22006"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
@@ -832,16 +832,23 @@ typedef struct sqlite3_mutex sqlite3_mutex;
 ** handled as a fatal error by SQLite, vfs implementations should endeavor
 ** to prevent this by setting mxPathname to a sufficiently large value.
 **
-** The xRandomness(), xSleep(), and xCurrentTime() interfaces
-** are not strictly a part of the filesystem, but they are
+** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
+** interfaces are not strictly a part of the filesystem, but they are
 ** included in the VFS structure for completeness.
 ** The xRandomness() function attempts to return nBytes bytes
 ** of good-quality randomness into zOut.  The return value is
 ** the actual number of bytes of randomness obtained.
 ** The xSleep() method causes the calling thread to sleep for at
 ** least the number of microseconds given.  The xCurrentTime()
-** method returns a Julian Day Number for the current date and time.
-**
+** method returns a Julian Day Number for the current date and time as
+** a floating point value.
+** The xCurrentTimeInt64() method returns, as an integer, the Julian
+** Day Number multipled by 86400000 (the number of milliseconds in 
+** a 24-hour day).  
+** ^SQLite will use the xCurrentTimeInt64() method to get the current
+** date and time if that method is available (if iVersion is 2 or 
+** greater and the function pointer is not NULL) and will fall back
+** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 */
 typedef struct sqlite3_vfs sqlite3_vfs;
 struct sqlite3_vfs {
@@ -868,7 +875,6 @@ struct sqlite3_vfs {
   ** The methods above are in version 1 of the sqlite_vfs object
   ** definition.  Those that follow are added in version 2 or later
   */
-  int (*xRename)(sqlite3_vfs*, const char *zOld, const char *zNew, int dirSync);
   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
   /*
   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.