Update sessions branch with latest changes from trunk.

FossilOrigin-Name: 01c84fd391a0ca1f5245c7eff0644d0cc6cff86b

22 files changed, 294 insertions, 186 deletions

diff --git a/src/backup.c b/src/backup.c
index f3b952bf0..aa3401897 100644
--- a/src/backup.c
+++ b/src/backup.c
@@ -678,9 +678,9 @@ int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
   pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
   if( pFd->pMethods ){
     i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);
-    sqlite3BeginBenignMalloc();
-    sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
-    sqlite3EndBenignMalloc();
+    rc = sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
+    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
+    if( rc ) goto copy_finished;
   }
 
   /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
@@ -705,12 +705,13 @@ int sqlite3BtreeCopyFile(Btree *pTo, Btree *pFrom){
   assert( b.rc!=SQLITE_OK );
   rc = sqlite3_backup_finish(&b);
   if( rc==SQLITE_OK ){
-    pTo->pBt->pageSizeFixed = 0;
+    pTo->pBt->btsFlags &= ~BTS_PAGESIZE_FIXED;
   }else{
     sqlite3PagerClearCache(sqlite3BtreePager(b.pDest));
   }
 
   assert( sqlite3BtreeIsInTrans(pTo)==0 );
+copy_finished:
   sqlite3BtreeLeave(pFrom);
   sqlite3BtreeLeave(pTo);
   return rc;
diff --git a/src/btree.c b/src/btree.c
index 7c043ccf7..253240665 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -243,7 +243,7 @@ static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
   /* If some other connection is holding an exclusive lock, the
   ** requested lock may not be obtained.
   */
-  if( pBt->pWriter!=p && pBt->isExclusive ){
+  if( pBt->pWriter!=p && (pBt->btsFlags & BTS_EXCLUSIVE)!=0 ){
     sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
     return SQLITE_LOCKED_SHAREDCACHE;
   }
@@ -264,7 +264,7 @@ static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
       sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
       if( eLock==WRITE_LOCK ){
         assert( p==pBt->pWriter );
-        pBt->isPending = 1;
+        pBt->btsFlags |= BTS_PENDING;
       }
       return SQLITE_LOCKED_SHAREDCACHE;
     }
@@ -352,7 +352,7 @@ static int setSharedCacheTableLock(Btree *p, Pgno iTable, u8 eLock){
 ** the setSharedCacheTableLock() procedure) held by Btree object p.
 **
 ** This function assumes that Btree p has an open read or write 
-** transaction. If it does not, then the BtShared.isPending variable
+** transaction. If it does not, then the BTS_PENDING flag
 ** may be incorrectly cleared.
 */
 static void clearAllSharedCacheTableLocks(Btree *p){
@@ -365,7 +365,7 @@ static void clearAllSharedCacheTableLocks(Btree *p){
 
   while( *ppIter ){
     BtLock *pLock = *ppIter;
-    assert( pBt->isExclusive==0 || pBt->pWriter==pLock->pBtree );
+    assert( (pBt->btsFlags & BTS_EXCLUSIVE)==0 || pBt->pWriter==pLock->pBtree );
     assert( pLock->pBtree->inTrans>=pLock->eLock );
     if( pLock->pBtree==p ){
       *ppIter = pLock->pNext;
@@ -378,22 +378,21 @@ static void clearAllSharedCacheTableLocks(Btree *p){
     }
   }
 
-  assert( pBt->isPending==0 || pBt->pWriter );
+  assert( (pBt->btsFlags & BTS_PENDING)==0 || pBt->pWriter );
   if( pBt->pWriter==p ){
     pBt->pWriter = 0;
-    pBt->isExclusive = 0;
-    pBt->isPending = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
   }else if( pBt->nTransaction==2 ){
     /* This function is called when Btree p is concluding its 
     ** transaction. If there currently exists a writer, and p is not
     ** that writer, then the number of locks held by connections other
     ** than the writer must be about to drop to zero. In this case
-    ** set the isPending flag to 0.
+    ** set the BTS_PENDING flag to 0.
     **
-    ** If there is not currently a writer, then BtShared.isPending must
+    ** If there is not currently a writer, then BTS_PENDING must
     ** be zero already. So this next line is harmless in that case.
     */
-    pBt->isPending = 0;
+    pBt->btsFlags &= ~BTS_PENDING;
   }
 }
 
@@ -405,8 +404,7 @@ static void downgradeAllSharedCacheTableLocks(Btree *p){
   if( pBt->pWriter==p ){
     BtLock *pLock;
     pBt->pWriter = 0;
-    pBt->isExclusive = 0;
-    pBt->isPending = 0;
+    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
     for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
       assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
       pLock->eLock = READ_LOCK;
@@ -1264,7 +1262,7 @@ static int freeSpace(MemPage *pPage, int start, int size){
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
   assert( size>=0 );   /* Minimum cell size is 4 */
 
-  if( pPage->pBt->secureDelete ){
+  if( pPage->pBt->btsFlags & BTS_SECURE_DELETE ){
     /* Overwrite deleted information with zeros when the secure_delete
     ** option is enabled */
     memset(&data[start], 0, size);
@@ -1367,6 +1365,7 @@ static int decodeFlags(MemPage *pPage, int flagByte){
   }else{
     return SQLITE_CORRUPT_BKPT;
   }
+  pPage->max1bytePayload = pBt->max1bytePayload;
   return SQLITE_OK;
 }
 
@@ -1502,7 +1501,7 @@ static void zeroPage(MemPage *pPage, int flags){
   assert( sqlite3PagerGetData(pPage->pDbPage) == data );
   assert( sqlite3PagerIswriteable(pPage->pDbPage) );
   assert( sqlite3_mutex_held(pBt->mutex) );
-  if( pBt->secureDelete ){
+  if( pBt->btsFlags & BTS_SECURE_DELETE ){
     memset(&data[hdr], 0, pBt->usableSize - hdr);
   }
   data[hdr] = (char)flags;
@@ -1855,9 +1854,9 @@ int sqlite3BtreeOpen(
   
     pBt->pCursor = 0;
     pBt->pPage1 = 0;
-    pBt->readOnly = sqlite3PagerIsreadonly(pBt->pPager);
+    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
 #ifdef SQLITE_SECURE_DELETE
-    pBt->secureDelete = 1;
+    pBt->btsFlags |= BTS_SECURE_DELETE;
 #endif
     pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
     if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
@@ -1878,7 +1877,7 @@ int sqlite3BtreeOpen(
       nReserve = 0;
     }else{
       nReserve = zDbHeader[20];
-      pBt->pageSizeFixed = 1;
+      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
 #ifndef SQLITE_OMIT_AUTOVACUUM
       pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
       pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
@@ -2166,7 +2165,7 @@ int sqlite3BtreeSyncDisabled(Btree *p){
 ** If parameter nReserve is less than zero, then the number of reserved
 ** bytes per page is left unchanged.
 **
-** If the iFix!=0 then the pageSizeFixed flag is set so that the page size
+** If the iFix!=0 then the BTS_PAGESIZE_FIXED flag is set so that the page size
 ** and autovacuum mode can no longer be changed.
 */
 int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
@@ -2174,7 +2173,7 @@ int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
   BtShared *pBt = p->pBt;
   assert( nReserve>=-1 && nReserve<=255 );
   sqlite3BtreeEnter(p);
-  if( pBt->pageSizeFixed ){
+  if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
     sqlite3BtreeLeave(p);
     return SQLITE_READONLY;
   }
@@ -2191,7 +2190,7 @@ int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
   }
   rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
   pBt->usableSize = pBt->pageSize - (u16)nReserve;
-  if( iFix ) pBt->pageSizeFixed = 1;
+  if( iFix ) pBt->btsFlags |= BTS_PAGESIZE_FIXED;
   sqlite3BtreeLeave(p);
   return rc;
 }
@@ -2231,8 +2230,8 @@ int sqlite3BtreeMaxPageCount(Btree *p, int mxPage){
 }
 
 /*
-** Set the secureDelete flag if newFlag is 0 or 1.  If newFlag is -1,
-** then make no changes.  Always return the value of the secureDelete
+** Set the BTS_SECURE_DELETE flag if newFlag is 0 or 1.  If newFlag is -1,
+** then make no changes.  Always return the value of the BTS_SECURE_DELETE
 ** setting after the change.
 */
 int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
@@ -2240,9 +2239,10 @@ int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
   if( p==0 ) return 0;
   sqlite3BtreeEnter(p);
   if( newFlag>=0 ){
-    p->pBt->secureDelete = (newFlag!=0) ? 1 : 0;
+    p->pBt->btsFlags &= ~BTS_SECURE_DELETE;
+    if( newFlag ) p->pBt->btsFlags |= BTS_SECURE_DELETE;
   } 
-  b = p->pBt->secureDelete;
+  b = (p->pBt->btsFlags & BTS_SECURE_DELETE)!=0;
   sqlite3BtreeLeave(p);
   return b;
 }
@@ -2263,7 +2263,7 @@ int sqlite3BtreeSetAutoVacuum(Btree *p, int autoVacuum){
   u8 av = (u8)autoVacuum;
 
   sqlite3BtreeEnter(p);
-  if( pBt->pageSizeFixed && (av ?1:0)!=pBt->autoVacuum ){
+  if( (pBt->btsFlags & BTS_PAGESIZE_FIXED)!=0 && (av ?1:0)!=pBt->autoVacuum ){
     rc = SQLITE_READONLY;
   }else{
     pBt->autoVacuum = av ?1:0;
@@ -2337,14 +2337,14 @@ static int lockBtree(BtShared *pBt){
 
 #ifdef SQLITE_OMIT_WAL
     if( page1[18]>1 ){
-      pBt->readOnly = 1;
+      pBt->btsFlags |= BTS_READ_ONLY;
     }
     if( page1[19]>1 ){
       goto page1_init_failed;
     }
 #else
     if( page1[18]>2 ){
-      pBt->readOnly = 1;
+      pBt->btsFlags |= BTS_READ_ONLY;
     }
     if( page1[19]>2 ){
       goto page1_init_failed;
@@ -2358,7 +2358,7 @@ static int lockBtree(BtShared *pBt){
     ** may not be the latest version - there may be a newer one in the log
     ** file.
     */
-    if( page1[19]==2 && pBt->doNotUseWAL==0 ){
+    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
       int isOpen = 0;
       rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
       if( rc!=SQLITE_OK ){
@@ -2435,6 +2435,11 @@ static int lockBtree(BtShared *pBt){
   pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
   pBt->maxLeaf = (u16)(pBt->usableSize - 35);
   pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
+  if( pBt->maxLocal>127 ){
+    pBt->max1bytePayload = 127;
+  }else{
+    pBt->max1bytePayload = (u8)pBt->maxLocal;
+  }
   assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
   pBt->pPage1 = pPage1;
   pBt->nPage = nPage;
@@ -2498,7 +2503,7 @@ static int newDatabase(BtShared *pBt){
   data[23] = 32;
   memset(&data[24], 0, 100-24);
   zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
-  pBt->pageSizeFixed = 1;
+  pBt->btsFlags |= BTS_PAGESIZE_FIXED;
 #ifndef SQLITE_OMIT_AUTOVACUUM
   assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
   assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
@@ -2562,7 +2567,7 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
   }
 
   /* Write transactions are not possible on a read-only database */
-  if( pBt->readOnly && wrflag ){
+  if( (pBt->btsFlags & BTS_READ_ONLY)!=0 && wrflag ){
     rc = SQLITE_READONLY;
     goto trans_begun;
   }
@@ -2572,7 +2577,9 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
   ** on this shared-btree structure and a second write transaction is
   ** requested, return SQLITE_LOCKED.
   */
-  if( (wrflag && pBt->inTransaction==TRANS_WRITE) || pBt->isPending ){
+  if( (wrflag && pBt->inTransaction==TRANS_WRITE)
+   || (pBt->btsFlags & BTS_PENDING)!=0
+  ){
     pBlock = pBt->pWriter->db;
   }else if( wrflag>1 ){
     BtLock *pIter;
@@ -2596,7 +2603,8 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
   rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
   if( SQLITE_OK!=rc ) goto trans_begun;
 
-  pBt->initiallyEmpty = (u8)(pBt->nPage==0);
+  pBt->btsFlags &= ~BTS_INITIALLY_EMPTY;
+  if( pBt->nPage==0 ) pBt->btsFlags |= BTS_INITIALLY_EMPTY;
   do {
     /* Call lockBtree() until either pBt->pPage1 is populated or
     ** lockBtree() returns something other than SQLITE_OK. lockBtree()
@@ -2608,7 +2616,7 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
     while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
 
     if( rc==SQLITE_OK && wrflag ){
-      if( pBt->readOnly ){
+      if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
         rc = SQLITE_READONLY;
       }else{
         rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
@@ -2645,7 +2653,8 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
 #ifndef SQLITE_OMIT_SHARED_CACHE
       assert( !pBt->pWriter );
       pBt->pWriter = p;
-      pBt->isExclusive = (u8)(wrflag>1);
+      pBt->btsFlags &= ~BTS_EXCLUSIVE;
+      if( wrflag>1 ) pBt->btsFlags |= BTS_EXCLUSIVE;
 #endif
 
       /* If the db-size header field is incorrect (as it may be if an old
@@ -3374,7 +3383,7 @@ int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
   BtShared *pBt = p->pBt;
   sqlite3BtreeEnter(p);
   assert( p->inTrans==TRANS_WRITE );
-  assert( pBt->readOnly==0 );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
   assert( iStatement>0 );
   assert( iStatement>p->db->nSavepoint );
   assert( pBt->inTransaction==TRANS_WRITE );
@@ -3409,7 +3418,9 @@ int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
     sqlite3BtreeEnter(p);
     rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
     if( rc==SQLITE_OK ){
-      if( iSavepoint<0 && pBt->initiallyEmpty ) pBt->nPage = 0;
+      if( iSavepoint<0 && (pBt->btsFlags & BTS_INITIALLY_EMPTY)!=0 ){
+        pBt->nPage = 0;
+      }
       rc = newDatabase(pBt);
       pBt->nPage = get4byte(28 + pBt->pPage1->aData);
 
@@ -3479,7 +3490,7 @@ static int btreeCursor(
   assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
   assert( pBt->pPage1 && pBt->pPage1->aData );
 
-  if( NEVER(wrFlag && pBt->readOnly) ){
+  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
     return SQLITE_READONLY;
   }
   if( iTable==1 && btreePagecount(pBt)==0 ){
@@ -4183,7 +4194,7 @@ static int moveToChild(BtCursor *pCur, u32 newPgno){
   return SQLITE_OK;
 }
 
-#ifndef NDEBUG
+#if 0
 /*
 ** Page pParent is an internal (non-leaf) tree page. This function 
 ** asserts that page number iChild is the left-child if the iIdx'th
@@ -4216,11 +4227,21 @@ static void moveToParent(BtCursor *pCur){
   assert( pCur->eState==CURSOR_VALID );
   assert( pCur->iPage>0 );
   assert( pCur->apPage[pCur->iPage] );
+
+  /* UPDATE: It is actually possible for the condition tested by the assert
+  ** below to be untrue if the database file is corrupt. This can occur if
+  ** one cursor has modified page pParent while a reference to it is held 
+  ** by a second cursor. Which can only happen if a single page is linked
+  ** into more than one b-tree structure in a corrupt database.  */
+#if 0
   assertParentIndex(
     pCur->apPage[pCur->iPage-1], 
     pCur->aiIdx[pCur->iPage-1], 
     pCur->apPage[pCur->iPage]->pgno
   );
+#endif
+  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );
+
   releasePage(pCur->apPage[pCur->iPage]);
   pCur->iPage--;
   pCur->info.nSize = 0;
@@ -4559,9 +4580,8 @@ int sqlite3BtreeMovetoUnpacked(
         ** 2 bytes of the cell.
         */
         int nCell = pCell[0];
-        if( !(nCell & 0x80)
-         && nCell<=pPage->maxLocal
-         && (pCell+nCell+1)<=pPage->aDataEnd
+        if( nCell<=pPage->max1bytePayload
+         /* && (pCell+nCell)<pPage->aDataEnd */
         ){
           /* This branch runs if the record-size field of the cell is a
           ** single byte varint and the record fits entirely on the main
@@ -4570,7 +4590,7 @@ int sqlite3BtreeMovetoUnpacked(
           c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
         }else if( !(pCell[1] & 0x80) 
           && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
-          && (pCell+nCell+2)<=pPage->aDataEnd
+          /* && (pCell+nCell+2)<=pPage->aDataEnd */
         ){
           /* The record-size field is a 2 byte varint and the record 
           ** fits entirely on the main b-tree page.  */
@@ -4691,7 +4711,13 @@ int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
   pPage = pCur->apPage[pCur->iPage];
   idx = ++pCur->aiIdx[pCur->iPage];
   assert( pPage->isInit );
-  assert( idx<=pPage->nCell );
+
+  /* If the database file is corrupt, it is possible for the value of idx 
+  ** to be invalid here. This can only occur if a second cursor modifies
+  ** the page while cursor pCur is holding a reference to it. Which can
+  ** only happen if the database is corrupt in such a way as to link the
+  ** page into more than one b-tree structure. */
+  testcase( idx>pPage->nCell );
 
   pCur->info.nSize = 0;
   pCur->validNKey = 0;
@@ -5116,7 +5142,7 @@ static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
   nFree = get4byte(&pPage1->aData[36]);
   put4byte(&pPage1->aData[36], nFree+1);
 
-  if( pBt->secureDelete ){
+  if( pBt->btsFlags & BTS_SECURE_DELETE ){
     /* If the secure_delete option is enabled, then
     ** always fully overwrite deleted information with zeros.
     */
@@ -5177,7 +5203,7 @@ static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
       if( rc==SQLITE_OK ){
         put4byte(&pTrunk->aData[4], nLeaf+1);
         put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
-        if( pPage && !pBt->secureDelete ){
+        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
           sqlite3PagerDontWrite(pPage->pDbPage);
         }
         rc = btreeSetHasContent(pBt, iPage);
@@ -6018,7 +6044,7 @@ static int balance_nonroot(
       ** In this case, temporarily copy the cell into the aOvflSpace[]
       ** buffer. It will be copied out again as soon as the aSpace[] buffer
       ** is allocated.  */
-      if( pBt->secureDelete ){
+      if( pBt->btsFlags & BTS_SECURE_DELETE ){
         int iOff;
 
         iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
@@ -6760,7 +6786,8 @@ int sqlite3BtreeInsert(
   }
 
   assert( cursorHoldsMutex(pCur) );
-  assert( pCur->wrFlag && pBt->inTransaction==TRANS_WRITE && !pBt->readOnly );
+  assert( pCur->wrFlag && pBt->inTransaction==TRANS_WRITE
+              && (pBt->btsFlags & BTS_READ_ONLY)==0 );
   assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
 
   /* Assert that the caller has been consistent. If this cursor was opened
@@ -6889,7 +6916,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
 
   assert( cursorHoldsMutex(pCur) );
   assert( pBt->inTransaction==TRANS_WRITE );
-  assert( !pBt->readOnly );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
   assert( pCur->wrFlag );
   assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
   assert( !hasReadConflicts(p, pCur->pgnoRoot) );
@@ -7010,7 +7037,7 @@ static int btreeCreateTable(Btree *p, int *piTable, int createTabFlags){
 
   assert( sqlite3BtreeHoldsMutex(p) );
   assert( pBt->inTransaction==TRANS_WRITE );
-  assert( !pBt->readOnly );
+  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
 
 #ifdef SQLITE_OMIT_AUTOVACUUM
   rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
@@ -7384,7 +7411,9 @@ void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
   /* If auto-vacuum is disabled in this build and this is an auto-vacuum
   ** database, mark the database as read-only.  */
 #ifdef SQLITE_OMIT_AUTOVACUUM
-  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ) pBt->readOnly = 1;
+  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
+    pBt->btsFlags |= BTS_READ_ONLY;
+  }
 #endif
 
   sqlite3BtreeLeave(p);
@@ -8184,7 +8213,8 @@ int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
   if( !pCsr->wrFlag ){
     return SQLITE_READONLY;
   }
-  assert( !pCsr->pBt->readOnly && pCsr->pBt->inTransaction==TRANS_WRITE );
+  assert( (pCsr->pBt->btsFlags & BTS_READ_ONLY)==0
+              && pCsr->pBt->inTransaction==TRANS_WRITE );
   assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
   assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
   assert( pCsr->apPage[pCsr->iPage]->intKey );
@@ -8224,7 +8254,8 @@ 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 = (u8)(iVersion==1);
+  pBt->btsFlags &= ~BTS_NO_WAL;
+  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;
 
   rc = sqlite3BtreeBeginTrans(pBtree, 0);
   if( rc==SQLITE_OK ){
@@ -8241,6 +8272,6 @@ int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
     }
   }
 
-  pBt->doNotUseWAL = 0;
+  pBt->btsFlags &= ~BTS_NO_WAL;
   return rc;
 }
diff --git a/src/btreeInt.h b/src/btreeInt.h
index 1535350a3..907c02e60 100644
--- a/src/btreeInt.h
+++ b/src/btreeInt.h
@@ -277,6 +277,7 @@ struct MemPage {
   u8 hasData;          /* True if this page stores data */
   u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
   u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
+  u8 max1bytePayload;  /* min(maxLocal,127) */
   u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
   u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
   u16 cellOffset;      /* Index in aData of first cell pointer */
@@ -407,17 +408,14 @@ struct BtShared {
   sqlite3 *db;          /* Database connection currently using this Btree */
   BtCursor *pCursor;    /* A list of all open cursors */
   MemPage *pPage1;      /* First page of the database */
-  u8 readOnly;          /* True if the underlying file is readonly */
-  u8 pageSizeFixed;     /* True if the page size can no longer be changed */
-  u8 secureDelete;      /* True if secure_delete is enabled */
-  u8 initiallyEmpty;    /* Database is empty at start of transaction */
   u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
 #ifndef SQLITE_OMIT_AUTOVACUUM
   u8 autoVacuum;        /* True if auto-vacuum is enabled */
   u8 incrVacuum;        /* True if incr-vacuum is enabled */
 #endif
   u8 inTransaction;     /* Transaction state */
-  u8 doNotUseWAL;       /* If true, do not open write-ahead-log file */
+  u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
+  u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
   u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
   u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
   u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
@@ -435,13 +433,22 @@ struct BtShared {
   BtShared *pNext;      /* Next on a list of sharable BtShared structs */
   BtLock *pLock;        /* List of locks held on this shared-btree struct */
   Btree *pWriter;       /* Btree with currently open write transaction */
-  u8 isExclusive;       /* True if pWriter has an EXCLUSIVE lock on the db */
-  u8 isPending;         /* If waiting for read-locks to clear */
 #endif
   u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
 };
 
 /*
+** Allowed values for BtShared.btsFlags
+*/
+#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
+#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
+#define BTS_SECURE_DELETE    0x0004   /* PRAGMA secure_delete is enabled */
+#define BTS_INITIALLY_EMPTY  0x0008   /* Database was empty at trans start */
+#define BTS_NO_WAL           0x0010   /* Do not open write-ahead-log files */
+#define BTS_EXCLUSIVE        0x0020   /* pWriter has an exclusive lock */
+#define BTS_PENDING          0x0040   /* Waiting for read-locks to clear */
+
+/*
 ** An instance of the following structure is used to hold information
 ** about a cell.  The parseCellPtr() function fills in this structure
 ** based on information extract from the raw disk page.
diff --git a/src/os.c b/src/os.c
index c26429bf9..b5e918a72 100644
--- a/src/os.c
+++ b/src/os.c
@@ -97,10 +97,23 @@ int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
   DO_OS_MALLOC_TEST(id);
   return id->pMethods->xCheckReservedLock(id, pResOut);
 }
+
+/*
+** Use sqlite3OsFileControl() when we are doing something that might fail
+** and we need to know about the failures.  Use sqlite3OsFileControlHint()
+** when simply tossing information over the wall to the VFS and we do not
+** really care if the VFS receives and understands the information since it
+** is only a hint and can be safely ignored.  The sqlite3OsFileControlHint()
+** routine has no return value since the return value would be meaningless.
+*/
 int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
   DO_OS_MALLOC_TEST(id);
   return id->pMethods->xFileControl(id, op, pArg);
 }
+void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
+  (void)id->pMethods->xFileControl(id, op, pArg);
+}
+
 int sqlite3OsSectorSize(sqlite3_file *id){
   int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
   return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
@@ -151,6 +164,7 @@ int sqlite3OsOpen(
 }
 int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
   DO_OS_MALLOC_TEST(0);
+  assert( dirSync==0 || dirSync==1 );
   return pVfs->xDelete(pVfs, zPath, dirSync);
 }
 int sqlite3OsAccess(
diff --git a/src/os.h b/src/os.h
index 52ac4b0cb..08cd178e7 100644
--- a/src/os.h
+++ b/src/os.h
@@ -252,6 +252,7 @@ int sqlite3OsLock(sqlite3_file*, int);
 int sqlite3OsUnlock(sqlite3_file*, int);
 int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
 int sqlite3OsFileControl(sqlite3_file*,int,void*);
+void sqlite3OsFileControlHint(sqlite3_file*,int,void*);
 #define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
 int sqlite3OsSectorSize(sqlite3_file *id);
 int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
@@ -260,6 +261,7 @@ int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
 void sqlite3OsShmBarrier(sqlite3_file *id);
 int sqlite3OsShmUnmap(sqlite3_file *id, int);
 
+
 /* 
 ** Functions for accessing sqlite3_vfs methods 
 */
diff --git a/src/os_unix.c b/src/os_unix.c
index 4f263bcdd..13faac3a5 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -225,7 +225,6 @@ struct unixFile {
   unsigned fsFlags;                   /* cached details from statfs() */
 #endif
 #if OS_VXWORKS
-  int isDelete;                       /* Delete on close if true */
   struct vxworksFileId *pId;          /* Unique file ID */
 #endif
 #ifndef NDEBUG
@@ -260,6 +259,9 @@ struct unixFile {
 # define UNIXFILE_DIRSYNC    0x00
 #endif
 #define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
+#define UNIXFILE_DELETE      0x20     /* Delete on close */
+#define UNIXFILE_URI         0x40     /* Filename might have query parameters */
+#define UNIXFILE_NOLOCK      0x80     /* Do no file locking */
 
 /*
 ** Include code that is common to all os_*.c files
@@ -1765,7 +1767,7 @@ static int closeUnixFile(sqlite3_file *id){
   }
 #if OS_VXWORKS
   if( pFile->pId ){
-    if( pFile->isDelete ){
+    if( pFile->ctrlFlags & UNIXFILE_DELETE ){
       osUnlink(pFile->pId->zCanonicalName);
     }
     vxworksReleaseFileId(pFile->pId);
@@ -3872,7 +3874,7 @@ static int unixOpenSharedMemory(unixFile *pDbFd){
       rc = SQLITE_NOMEM;
       goto shm_open_err;
     }
-    memset(pShmNode, 0, sizeof(*pShmNode));
+    memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
     zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1];
 #ifdef SQLITE_SHM_DIRECTORY
     sqlite3_snprintf(nShmFilename, zShmFilename, 
@@ -4555,12 +4557,9 @@ typedef const sqlite3_io_methods *(*finder_type)(const char*,unixFile*);
 static int fillInUnixFile(
   sqlite3_vfs *pVfs,      /* Pointer to vfs object */
   int h,                  /* Open file descriptor of file being opened */
-  int syncDir,            /* True to sync directory on first sync */
   sqlite3_file *pId,      /* Write to the unixFile structure here */
   const char *zFilename,  /* Name of the file being opened */
-  int noLock,             /* Omit locking if true */
-  int isDelete,           /* Delete on close if true */
-  int isReadOnly          /* True if the file is opened read-only */
+  int ctrlFlags           /* Zero or more UNIXFILE_* values */
 ){
   const sqlite3_io_methods *pLockingStyle;
   unixFile *pNew = (unixFile *)pId;
@@ -4568,11 +4567,6 @@ static int fillInUnixFile(
 
   assert( pNew->pInode==NULL );
 
-  /* Parameter isDelete is only used on vxworks. Express this explicitly 
-  ** here to prevent compiler warnings about unused parameters.
-  */
-  UNUSED_PARAMETER(isDelete);
-
   /* Usually the path zFilename should not be a relative pathname. The
   ** exception is when opening the proxy "conch" file in builds that
   ** include the special Apple locking styles.
@@ -4585,35 +4579,30 @@ static int fillInUnixFile(
 #endif
 
   /* No locking occurs in temporary files */
-  assert( zFilename!=0 || noLock );
+  assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 );
 
   OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
   pNew->h = h;
   pNew->pVfs = pVfs;
   pNew->zPath = zFilename;
-  pNew->ctrlFlags = 0;
-  if( sqlite3_uri_boolean(zFilename, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
+  pNew->ctrlFlags = (u8)ctrlFlags;
+  if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),
+                           "psow", SQLITE_POWERSAFE_OVERWRITE) ){
     pNew->ctrlFlags |= UNIXFILE_PSOW;
   }
   if( memcmp(pVfs->zName,"unix-excl",10)==0 ){
     pNew->ctrlFlags |= UNIXFILE_EXCL;
   }
-  if( isReadOnly ){
-    pNew->ctrlFlags |= UNIXFILE_RDONLY;
-  }
-  if( syncDir ){
-    pNew->ctrlFlags |= UNIXFILE_DIRSYNC;
-  }
 
 #if OS_VXWORKS
   pNew->pId = vxworksFindFileId(zFilename);
   if( pNew->pId==0 ){
-    noLock = 1;
+    ctrlFlags |= UNIXFILE_NOLOCK;
     rc = SQLITE_NOMEM;
   }
 #endif
 
-  if( noLock ){
+  if( ctrlFlags & UNIXFILE_NOLOCK ){
     pLockingStyle = &nolockIoMethods;
   }else{
     pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
@@ -4734,7 +4723,7 @@ static int fillInUnixFile(
     osUnlink(zFilename);
     isDelete = 0;
   }
-  pNew->isDelete = isDelete;
+  if( isDelete ) pNew->ctrlFlags |= UNIXFILE_DELETE;
 #endif
   if( rc!=SQLITE_OK ){
     if( h>=0 ) robust_close(pNew, h, __LINE__);
@@ -4799,18 +4788,19 @@ static int unixGetTempname(int nBuf, char *zBuf){
   /* Check that the output buffer is large enough for the temporary file 
   ** name. If it is not, return SQLITE_ERROR.
   */
-  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 17) >= (size_t)nBuf ){
+  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 18) >= (size_t)nBuf ){
     return SQLITE_ERROR;
   }
 
   do{
-    sqlite3_snprintf(nBuf-17, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
+    sqlite3_snprintf(nBuf-18, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
     j = (int)strlen(zBuf);
     sqlite3_randomness(15, &zBuf[j]);
     for(i=0; i<15; i++, j++){
       zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
     }
     zBuf[j] = 0;
+    zBuf[j+1] = 0;
   }while( osAccess(zBuf,0)==0 );
   return SQLITE_OK;
 }
@@ -4989,6 +4979,7 @@ static int unixOpen(
   int eType = flags&0xFFFFFF00;  /* Type of file to open */
   int noLock;                    /* True to omit locking primitives */
   int rc = SQLITE_OK;            /* Function Return Code */
+  int ctrlFlags = 0;             /* UNIXFILE_* flags */
 
   int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
   int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
@@ -5015,7 +5006,7 @@ static int unixOpen(
   /* If argument zPath is a NULL pointer, this function is required to open
   ** a temporary file. Use this buffer to store the file name in.
   */
-  char zTmpname[MAX_PATHNAME+1];
+  char zTmpname[MAX_PATHNAME+2];
   const char *zName = zPath;
 
   /* Check the following statements are true: 
@@ -5058,14 +5049,24 @@ static int unixOpen(
       }
     }
     p->pUnused = pUnused;
+
+    /* Database filenames are double-zero terminated if they are not
+    ** URIs with parameters.  Hence, they can always be passed into
+    ** sqlite3_uri_parameter(). */
+    assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 );
+
   }else if( !zName ){
     /* If zName is NULL, the upper layer is requesting a temp file. */
     assert(isDelete && !syncDir);
-    rc = unixGetTempname(MAX_PATHNAME+1, zTmpname);
+    rc = unixGetTempname(MAX_PATHNAME+2, zTmpname);
     if( rc!=SQLITE_OK ){
       return rc;
     }
     zName = zTmpname;
+
+    /* Generated temporary filenames are always double-zero terminated
+    ** for use by sqlite3_uri_parameter(). */
+    assert( zName[strlen(zName)+1]==0 );
   }
 
   /* Determine the value of the flags parameter passed to POSIX function
@@ -5142,7 +5143,14 @@ static int unixOpen(
     ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
   }
 #endif
-  
+
+  /* Set up appropriate ctrlFlags */
+  if( isDelete )                ctrlFlags |= UNIXFILE_DELETE;
+  if( isReadonly )              ctrlFlags |= UNIXFILE_RDONLY;
+  if( noLock )                  ctrlFlags |= UNIXFILE_NOLOCK;
+  if( syncDir )                 ctrlFlags |= UNIXFILE_DIRSYNC;
+  if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI;
+
 #if SQLITE_ENABLE_LOCKING_STYLE
 #if SQLITE_PREFER_PROXY_LOCKING
   isAutoProxy = 1;
@@ -5172,8 +5180,7 @@ static int unixOpen(
       useProxy = !(fsInfo.f_flags&MNT_LOCAL);
     }
     if( useProxy ){
-      rc = fillInUnixFile(pVfs, fd, syncDir, pFile, zPath, noLock,
-                          isDelete, isReadonly);
+      rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
       if( rc==SQLITE_OK ){
         rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
         if( rc!=SQLITE_OK ){
@@ -5190,8 +5197,8 @@ static int unixOpen(
   }
 #endif
   
-  rc = fillInUnixFile(pVfs, fd, syncDir, pFile, zPath, noLock,
-                      isDelete, isReadonly);
+  rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);
+
 open_finished:
   if( rc!=SQLITE_OK ){
     sqlite3_free(p->pUnused);
@@ -5216,7 +5223,7 @@ static int unixDelete(
     return unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
   }
 #ifndef SQLITE_DISABLE_DIRSYNC
-  if( dirSync ){
+  if( (dirSync & 1)!=0 ){
     int fd;
     rc = osOpenDirectory(zPath, &fd);
     if( rc==SQLITE_OK ){
@@ -5862,7 +5869,7 @@ static int proxyCreateUnixFile(
   pUnused->flags = openFlags;
   pNew->pUnused = pUnused;
   
-  rc = fillInUnixFile(&dummyVfs, fd, 0, (sqlite3_file*)pNew, path, 0, 0, 0);
+  rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0);
   if( rc==SQLITE_OK ){
     *ppFile = pNew;
     return SQLITE_OK;
diff --git a/src/os_win.c b/src/os_win.c
index 7269f436d..8b86c7ed5 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -2428,7 +2428,9 @@ static void winShmPurge(sqlite3_vfs *pVfs, int deleteFlag){
       }
       if( deleteFlag ){
         SimulateIOErrorBenign(1);
+        sqlite3BeginBenignMalloc();
         winDelete(pVfs, p->zFilename, 0);
+        sqlite3EndBenignMalloc();
         SimulateIOErrorBenign(0);
       }
       *pp = p->pNext;
@@ -2463,12 +2465,12 @@ static int winOpenSharedMemory(winFile *pDbFd){
   if( p==0 ) return SQLITE_IOERR_NOMEM;
   memset(p, 0, sizeof(*p));
   nName = sqlite3Strlen30(pDbFd->zPath);
-  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 16 );
+  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 17 );
   if( pNew==0 ){
     sqlite3_free(p);
     return SQLITE_IOERR_NOMEM;
   }
-  memset(pNew, 0, sizeof(*pNew));
+  memset(pNew, 0, sizeof(*pNew) + nName + 17);
   pNew->zFilename = (char*)&pNew[1];
   sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
   sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename); 
@@ -2504,7 +2506,6 @@ static int winOpenSharedMemory(winFile *pDbFd){
                  SQLITE_OPEN_WAL | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Mode flags */
                  0);
     if( SQLITE_OK!=rc ){
-      rc = SQLITE_CANTOPEN_BKPT;
       goto shm_open_err;
     }
 
@@ -2927,7 +2928,7 @@ static int getTempname(int nBuf, char *zBuf){
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "0123456789";
   size_t i, j;
-  char zTempPath[MAX_PATH+1];
+  char zTempPath[MAX_PATH+2];
 
   /* It's odd to simulate an io-error here, but really this is just
   ** using the io-error infrastructure to test that SQLite handles this
@@ -2970,14 +2971,14 @@ static int getTempname(int nBuf, char *zBuf){
   /* Check that the output buffer is large enough for the temporary file 
   ** name. If it is not, return SQLITE_ERROR.
   */
-  if( (sqlite3Strlen30(zTempPath) + sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX) + 17) >= nBuf ){
+  if( (sqlite3Strlen30(zTempPath) + sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX) + 18) >= nBuf ){
     return SQLITE_ERROR;
   }
 
   for(i=sqlite3Strlen30(zTempPath); i>0 && zTempPath[i-1]=='\\'; i--){}
   zTempPath[i] = 0;
 
-  sqlite3_snprintf(nBuf-17, zBuf,
+  sqlite3_snprintf(nBuf-18, zBuf,
                    "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
   j = sqlite3Strlen30(zBuf);
   sqlite3_randomness(15, &zBuf[j]);
@@ -2985,6 +2986,7 @@ static int getTempname(int nBuf, char *zBuf){
     zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
   }
   zBuf[j] = 0;
+  zBuf[j+1] = 0;
 
   OSTRACE(("TEMP FILENAME: %s\n", zBuf));
   return SQLITE_OK; 
@@ -3017,7 +3019,7 @@ static int winOpen(
   /* If argument zPath is a NULL pointer, this function is required to open
   ** a temporary file. Use this buffer to store the file name in.
   */
-  char zTmpname[MAX_PATH+1];     /* Buffer used to create temp filename */
+  char zTmpname[MAX_PATH+2];     /* Buffer used to create temp filename */
 
   int rc = SQLITE_OK;            /* Function Return Code */
 #if !defined(NDEBUG) || SQLITE_OS_WINCE
@@ -3076,13 +3078,20 @@ static int winOpen(
   */
   if( !zUtf8Name ){
     assert(isDelete && !isOpenJournal);
-    rc = getTempname(MAX_PATH+1, zTmpname);
+    rc = getTempname(MAX_PATH+2, zTmpname);
     if( rc!=SQLITE_OK ){
       return rc;
     }
     zUtf8Name = zTmpname;
   }
 
+  /* Database filenames are double-zero terminated if they are not
+  ** URIs with parameters.  Hence, they can always be passed into
+  ** sqlite3_uri_parameter().
+  */
+  assert( (eType!=SQLITE_OPEN_MAIN_DB) || (flags & SQLITE_OPEN_URI) ||
+        zUtf8Name[strlen(zUtf8Name)+1]==0 );
+
   /* Convert the filename to the system encoding. */
   zConverted = convertUtf8Filename(zUtf8Name);
   if( zConverted==0 ){
diff --git a/src/pager.c b/src/pager.c
index c57fe1874..6f3b65166 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -2486,10 +2486,9 @@ static int pager_truncate(Pager *pPager, Pgno nPage){
     if( rc==SQLITE_OK && currentSize!=newSize ){
       if( currentSize>newSize ){
         rc = sqlite3OsTruncate(pPager->fd, newSize);
-      }else{
+      }else if( (currentSize+szPage)<=newSize ){
         char *pTmp = pPager->pTmpSpace;
         memset(pTmp, 0, szPage);
-        testcase( (newSize-szPage) <  currentSize );
         testcase( (newSize-szPage) == currentSize );
         testcase( (newSize-szPage) >  currentSize );
         rc = sqlite3OsWrite(pPager->fd, pTmp, szPage, newSize-szPage);
@@ -2747,10 +2746,11 @@ end_playback:
   ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
   ** assertion that the transaction counter was modified.
   */
-  assert(
-    pPager->fd->pMethods==0 ||
-    sqlite3OsFileControl(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0)>=SQLITE_OK
-  );
+#ifdef SQLITE_DEBUG
+  if( pPager->fd->pMethods ){
+    sqlite3OsFileControlHint(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0);
+  }
+#endif
 
   /* If this playback is happening automatically as a result of an IO or 
   ** malloc error that occurred after the change-counter was updated but 
@@ -3087,10 +3087,7 @@ static int pagerPagecount(Pager *pPager, Pgno *pnPage){
         return rc;
       }
     }
-    nPage = (Pgno)(n / pPager->pageSize);
-    if( nPage==0 && n>0 ){
-      nPage = 1;
-    }
+    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);
   }
 
   /* If the current number of pages in the file is greater than the
@@ -3521,7 +3518,7 @@ int sqlite3PagerSetPagesize(Pager *pPager, u32 *pPageSize, int nReserve){
 
     if( rc==SQLITE_OK ){
       pager_reset(pPager);
-      pPager->dbSize = (Pgno)(nByte/pageSize);
+      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
       pPager->pageSize = pageSize;
       sqlite3PageFree(pPager->pTmpSpace);
       pPager->pTmpSpace = pNew;
@@ -4029,9 +4026,7 @@ static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
   assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
   if( rc==SQLITE_OK && pPager->dbSize>pPager->dbHintSize ){
     sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
-    sqlite3BeginBenignMalloc();
-    sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
-    sqlite3EndBenignMalloc();
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
     pPager->dbHintSize = pPager->dbSize;
   }
 
@@ -6055,7 +6050,8 @@ int sqlite3PagerRollback(Pager *pPager){
   }
 
   assert( pPager->eState==PAGER_READER || rc!=SQLITE_OK );
-  assert( rc==SQLITE_OK || rc==SQLITE_FULL || (rc&0xFF)==SQLITE_IOERR );
+  assert( rc==SQLITE_OK || rc==SQLITE_FULL
+          || rc==SQLITE_NOMEM || (rc&0xFF)==SQLITE_IOERR );
 
   /* If an error occurs during a ROLLBACK, we can no longer trust the pager
   ** cache. So call pager_error() on the way out to make any error persistent.
diff --git a/src/pcache1.c b/src/pcache1.c
index 405ae5aec..f76d7c8e8 100644
--- a/src/pcache1.c
+++ b/src/pcache1.c
@@ -40,7 +40,7 @@ typedef struct PGroup PGroup;
 ** Mode 1 uses more memory (since PCache instances are not able to rob
 ** unused pages from other PCaches) but it also operates without a mutex,
 ** and is therefore often faster.  Mode 2 requires a mutex in order to be
-** threadsafe, but is able recycle pages more efficient.
+** threadsafe, but recycles pages more efficiently.
 **
 ** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
 ** PGroup which is the pcache1.grp global variable and its mutex is
@@ -66,7 +66,7 @@ struct PGroup {
 struct PCache1 {
   /* Cache configuration parameters. Page size (szPage) and the purgeable
   ** flag (bPurgeable) are set when the cache is created. nMax may be 
-  ** modified at any time by a call to the pcache1CacheSize() method.
+  ** modified at any time by a call to the pcache1Cachesize() method.
   ** The PGroup mutex must be held when accessing nMax.
   */
   PGroup *pGroup;                     /* PGroup this cache belongs to */
@@ -357,7 +357,7 @@ void sqlite3PageFree(void *p){
 ** for all page cache needs and we should not need to spill the
 ** allocation onto the heap.
 **
-** Or, the heap is used for all page cache memory put the heap is
+** Or, the heap is used for all page cache memory but the heap is
 ** under memory pressure, then again it is desirable to avoid
 ** allocating a new page cache entry in order to avoid stressing
 ** the heap even further.
@@ -668,7 +668,7 @@ static int pcache1Pagecount(sqlite3_pcache *p){
 ** For a non-purgeable cache (a cache used as the storage for an in-memory
 ** database) there is really no difference between createFlag 1 and 2.  So
 ** the calling function (pcache.c) will never have a createFlag of 1 on
-** a non-purgable cache.
+** a non-purgeable cache.
 **
 ** There are three different approaches to obtaining space for a page,
 ** depending on the value of parameter createFlag (which may be 0, 1 or 2).
diff --git a/src/pragma.c b/src/pragma.c
index bfdcb2370..581bcaf0e 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -795,7 +795,7 @@ void sqlite3Pragma(
       Pager *pPager = sqlite3BtreePager(pDb->pBt);
       char *proxy_file_path = NULL;
       sqlite3_file *pFile = sqlite3PagerFile(pPager);
-      sqlite3OsFileControl(pFile, SQLITE_GET_LOCKPROXYFILE, 
+      sqlite3OsFileControlHint(pFile, SQLITE_GET_LOCKPROXYFILE, 
                            &proxy_file_path);
       
       if( proxy_file_path ){
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index a91997f9d..af1abecf4 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -2627,8 +2627,10 @@ int sqlite3_open_v2(
 ** to see if a database file was a URI that contained a specific query 
 ** parameter, and if so obtains the value of that query parameter.
 **
-** If F is the filename pointer passed into the xOpen() method of a VFS
-** implementation and P is the name of the query parameter, then
+** If F is the database filename pointer passed into the xOpen() method of 
+** a VFS implementation when the flags parameter to xOpen() has one or 
+** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
+** P is the name of the query parameter, then
 ** sqlite3_uri_parameter(F,P) returns the value of the P
 ** parameter if it exists or a NULL pointer if P does not appear as a 
 ** query parameter on F.  If P is a query parameter of F
@@ -2648,8 +2650,9 @@ int sqlite3_open_v2(
 ** 
 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
 ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
-** is not a pathname pointer that SQLite passed into the xOpen VFS method,
-** then the behavior of this routine is undefined and probably undesirable.
+** is not a database file pathname pointer that SQLite passed into the xOpen
+** VFS method, then the behavior of this routine is undefined and probably
+** undesirable.
 */
 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
 int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
@@ -6205,7 +6208,7 @@ struct sqlite3_pcache_page {
 ** [[the xShrink() page cache method]]
 ** ^SQLite invokes the xShrink() method when it wants the page cache to
 ** free up as much of heap memory as possible.  The page cache implementation
-** is not obligated to free any memory, but well-behaved implementions should
+** is not obligated to free any memory, but well-behaved implementations should
 ** do their best.
 */
 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
diff --git a/src/tclsqlite.c b/src/tclsqlite.c
index 4e7f2acbb..f2a517c8f 100644
--- a/src/tclsqlite.c
+++ b/src/tclsqlite.c
@@ -3163,7 +3163,7 @@ static int DbMain(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
   if( objc<3 || (objc&1)!=1 ){
     Tcl_WrongNumArgs(interp, 1, objv, 
       "HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
-      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN?"
+      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
 #ifdef SQLITE_HAS_CODEC
       " ?-key CODECKEY?"
 #endif
diff --git a/src/test2.c b/src/test2.c
index fa7dd76ce..8343692f6 100644
--- a/src/test2.c
+++ b/src/test2.c
@@ -537,6 +537,8 @@ static int fake_big_file(
   int rc;
   int n;
   i64 offset;
+  char *zFile;
+  int nFile;
   if( argc!=3 ){
     Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
        " N-MEGABYTES FILE\"", 0);
@@ -545,17 +547,24 @@ static int fake_big_file(
   if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;
 
   pVfs = sqlite3_vfs_find(0);
-  rc = sqlite3OsOpenMalloc(pVfs, argv[2], &fd, 
+  nFile = strlen(argv[2]);
+  zFile = sqlite3_malloc( nFile+2 );
+  if( zFile==0 ) return TCL_ERROR;
+  memcpy(zFile, argv[2], nFile+1);
+  zFile[nFile+1] = 0;
+  rc = sqlite3OsOpenMalloc(pVfs, zFile, &fd, 
       (SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB), 0
   );
   if( rc ){
     Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
+    sqlite3_free(zFile);
     return TCL_ERROR;
   }
   offset = n;
   offset *= 1024*1024;
   rc = sqlite3OsWrite(fd, "Hello, World!", 14, offset);
   sqlite3OsCloseFree(fd);
+  sqlite3_free(zFile);
   if( rc ){
     Tcl_AppendResult(interp, "write failed: ", errorName(rc), 0);
     return TCL_ERROR;
diff --git a/src/test3.c b/src/test3.c
index 4eabdccfd..9bac2cac1 100644
--- a/src/test3.c
+++ b/src/test3.c
@@ -66,6 +66,8 @@ static int btree_open(
   Btree *pBt;
   int rc, nCache;
   char zBuf[100];
+  int n;
+  char *zFilename;
   if( argc!=3 ){
     Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
        " FILENAME NCACHE FLAGS\"", 0);
@@ -78,8 +80,14 @@ static int btree_open(
     sDb.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
     sqlite3_mutex_enter(sDb.mutex);
   }
-  rc = sqlite3BtreeOpen(sDb.pVfs, argv[1], &sDb, &pBt, 0, 
+  n = strlen(argv[1]);
+  zFilename = sqlite3_malloc( n+2 );
+  if( zFilename==0 ) return TCL_ERROR;
+  memcpy(zFilename, argv[1], n+1);
+  zFilename[n+1] = 0;
+  rc = sqlite3BtreeOpen(sDb.pVfs, zFilename, &sDb, &pBt, 0, 
      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_MAIN_DB);
+  sqlite3_free(zFilename);
   if( rc!=SQLITE_OK ){
     Tcl_AppendResult(interp, errorName(rc), 0);
     return TCL_ERROR;
diff --git a/src/test_journal.c b/src/test_journal.c
index ef8207032..00567db59 100644
--- a/src/test_journal.c
+++ b/src/test_journal.c
@@ -409,6 +409,7 @@ static int openTransaction(jt_file *pMain, jt_file *pJournal){
         if( iOff==PENDING_BYTE ) continue;
         rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);
         pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);
+        if( ii+1==pMain->nPage && rc==SQLITE_IOERR_SHORT_READ ) rc = SQLITE_OK;
       }
     }
 
@@ -662,7 +663,7 @@ static int jtCheckReservedLock(sqlite3_file *pFile, int *pResOut){
 */
 static int jtFileControl(sqlite3_file *pFile, int op, void *pArg){
   jt_file *p = (jt_file *)pFile;
-  return sqlite3OsFileControl(p->pReal, op, pArg);
+  return p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
 }
 
 /*
diff --git a/src/test_multiplex.c b/src/test_multiplex.c
index eceb8d74a..af41c0b61 100644
--- a/src/test_multiplex.c
+++ b/src/test_multiplex.c
@@ -220,9 +220,27 @@ static int multiplexStrlen30(const char *z){
 /*
 ** Generate the file-name for chunk iChunk of the group with base name
 ** zBase. The file-name is written to buffer zOut before returning. Buffer
-** zOut must be allocated by the caller so that it is at least (nBase+4)
+** zOut must be allocated by the caller so that it is at least (nBase+5)
 ** bytes in size, where nBase is the length of zBase, not including the
 ** nul-terminator.
+**
+** If iChunk is 0 (or 400 - the number for the first journal file chunk),
+** the output is a copy of the input string. Otherwise, if 
+** SQLITE_ENABLE_8_3_NAMES is not defined or the input buffer does not contain
+** a "." character, then the output is a copy of the input string with the 
+** three-digit zero-padded decimal representation if iChunk appended to it. 
+** For example:
+**
+**   zBase="test.db", iChunk=4  ->  zOut="test.db004"
+**
+** Or, if SQLITE_ENABLE_8_3_NAMES is defined and the input buffer contains
+** a "." character, then everything after the "." is replaced by the 
+** three-digit representation of iChunk.
+**
+**   zBase="test.db", iChunk=4  ->  zOut="test.004"
+**
+** The output buffer string is terminated by 2 0x00 bytes. This makes it safe
+** to pass to sqlite3_uri_parameter() and similar.
 */
 static void multiplexFilename(
   const char *zBase,              /* Filename for chunk 0 */
@@ -231,9 +249,9 @@ static void multiplexFilename(
   int iChunk,                     /* Chunk to generate filename for */
   char *zOut                      /* Buffer to write generated name to */
 ){
-  memcpy(zOut, zBase, nBase+1);
+  int n = nBase;
+  memcpy(zOut, zBase, n+1);
   if( iChunk!=0 && iChunk!=SQLITE_MULTIPLEX_JOURNAL_8_3_OFFSET ){
-    int n = nBase;
 #ifdef SQLITE_ENABLE_8_3_NAMES
     int i;
     for(i=n-1; i>0 && i>=n-4 && zOut[i]!='.'; i--){}
@@ -247,7 +265,11 @@ static void multiplexFilename(
     }
 #endif
     sqlite3_snprintf(4,&zOut[n],"%03d",iChunk);
+    n += 3;
   }
+
+  assert( zOut[n]=='\0' );
+  zOut[n+1] = '\0';
 }
 
 /* Compute the filename for the iChunk-th chunk
@@ -266,7 +288,7 @@ static int multiplexSubFilename(multiplexGroup *pGroup, int iChunk){
   if( pGroup->zName && pGroup->aReal[iChunk].z==0 ){
     char *z;
     int n = pGroup->nName;
-    pGroup->aReal[iChunk].z = z = sqlite3_malloc( n+4 );
+    pGroup->aReal[iChunk].z = z = sqlite3_malloc( n+5 );
     if( z==0 ){
       return SQLITE_NOMEM;
     }
@@ -306,7 +328,6 @@ static sqlite3_file *multiplexSubOpen(
   *rc = multiplexSubFilename(pGroup, iChunk);
   if( (*rc)==SQLITE_OK && (pSubOpen = pGroup->aReal[iChunk].p)==0 ){
     int flags, bExists;
-    createFlag = (pGroup->flags & SQLITE_OPEN_CREATE)!=0;
     flags = pGroup->flags;
     if( createFlag ){
       flags |= SQLITE_OPEN_CREATE;
@@ -350,6 +371,7 @@ static sqlite3_int64 multiplexSubSize(
   sqlite3_file *pSub;
   sqlite3_int64 sz = 0;
 
+  if( *rc ) return 0;
   pSub = multiplexSubOpen(pGroup, iChunk, rc, NULL, 0);
   if( pSub==0 ) return 0;
   *rc = pSub->pMethods->xFileSize(pSub, &sz);
@@ -491,13 +513,14 @@ static int multiplexOpen(
   }
 
   if( rc==SQLITE_OK ){
+    const char *zUri = (flags & SQLITE_OPEN_URI) ? zName : 0;
     /* assign pointers to extra space allocated */
     memset(pGroup, 0, sz);
     pMultiplexOpen->pGroup = pGroup;
     pGroup->bEnabled = -1;
-    pGroup->bTruncate = sqlite3_uri_boolean(zName, "truncate", 
-                                 (flags & SQLITE_OPEN_MAIN_DB)==0);
-    pGroup->szChunk = sqlite3_uri_int64(zName, "chunksize",
+    pGroup->bTruncate = sqlite3_uri_boolean(zUri, "truncate", 
+                                   (flags & SQLITE_OPEN_MAIN_DB)==0);
+    pGroup->szChunk = sqlite3_uri_int64(zUri, "chunksize",
                                         SQLITE_MULTIPLEX_CHUNK_SIZE);
     pGroup->szChunk = (pGroup->szChunk+0xffff)&~0xffff;
     if( zName ){
@@ -611,7 +634,7 @@ static int multiplexDelete(
     */
     int nName = strlen(zName);
     char *z;
-    z = sqlite3_malloc(nName + 4);
+    z = sqlite3_malloc(nName + 5);
     if( z==0 ){
       rc = SQLITE_IOERR_NOMEM;
     }else{
diff --git a/src/test_quota.c b/src/test_quota.c
index 4529bd302..c8ed7389e 100644
--- a/src/test_quota.c
+++ b/src/test_quota.c
@@ -937,30 +937,38 @@ int sqlite3_quota_file(const char *zFilename){
   int rc;
   int outFlags = 0;
   sqlite3_int64 iSize;
-  fd = (sqlite3_file*)sqlite3_malloc(gQuota.sThisVfs.szOsFile +
-                                     gQuota.sThisVfs.mxPathname+1);
-  if( fd==0 ) return SQLITE_NOMEM;
-  zFull = gQuota.sThisVfs.szOsFile + (char*)fd;
-  rc = gQuota.pOrigVfs->xFullPathname(gQuota.pOrigVfs, zFilename,
-                                      gQuota.sThisVfs.mxPathname+1, zFull);
+  int nAlloc = gQuota.sThisVfs.szOsFile + gQuota.sThisVfs.mxPathname+2;
+
+  /* Allocate space for a file-handle and the full path for file zFilename */
+  fd = (sqlite3_file *)sqlite3_malloc(nAlloc);
+  if( fd==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    zFull = &((char *)fd)[gQuota.sThisVfs.szOsFile];
+    rc = gQuota.pOrigVfs->xFullPathname(gQuota.pOrigVfs, zFilename,
+        gQuota.sThisVfs.mxPathname+1, zFull);
+  }
+
   if( rc==SQLITE_OK ){
+    zFull[strlen(zFull)+1] = '\0';
     rc = quotaOpen(&gQuota.sThisVfs, zFull, fd, 
                    SQLITE_OPEN_READONLY | SQLITE_OPEN_MAIN_DB, &outFlags);
-  }
-  if( rc==SQLITE_OK ){
-    fd->pMethods->xFileSize(fd, &iSize);
-    fd->pMethods->xClose(fd);
-  }else if( rc==SQLITE_CANTOPEN ){
-    quotaGroup *pGroup;
-    quotaFile *pFile;
-    quotaEnter();
-    pGroup = quotaGroupFind(zFull);
-    if( pGroup ){
-      pFile = quotaFindFile(pGroup, zFull, 0);
-      if( pFile ) quotaRemoveFile(pFile);
+    if( rc==SQLITE_OK ){
+      fd->pMethods->xFileSize(fd, &iSize);
+      fd->pMethods->xClose(fd);
+    }else if( rc==SQLITE_CANTOPEN ){
+      quotaGroup *pGroup;
+      quotaFile *pFile;
+      quotaEnter();
+      pGroup = quotaGroupFind(zFull);
+      if( pGroup ){
+        pFile = quotaFindFile(pGroup, zFull, 0);
+        if( pFile ) quotaRemoveFile(pFile);
+      }
+      quotaLeave();
     }
-    quotaLeave();
   }
+
   sqlite3_free(fd);
   return rc;
 }
diff --git a/src/util.c b/src/util.c
index 4a332a5e9..fd3c858ab 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1164,10 +1164,6 @@ int sqlite3AbsInt32(int x){
 ** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
 ** do the suffix shortening regardless of URI parameter.
 **
-** Assume that zBaseFilename contains two \000 terminator bytes (so that
-** it can be harmlessly passed into sqlite3_uri_parameter()) and copy both
-** zero terminator bytes into the end of the revised name.
-**
 ** Examples:
 **
 **     test.db-journal    =>   test.nal
@@ -1176,7 +1172,6 @@ int sqlite3AbsInt32(int x){
 **     test.db-mj7f3319fa =>   test.9fa
 */
 void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
-  assert( zBaseFilename[strlen(zBaseFilename)+1]==0 );
 #if SQLITE_ENABLE_8_3_NAMES<2
   if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
 #endif
@@ -1184,7 +1179,7 @@ void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
     int i, sz;
     sz = sqlite3Strlen30(z);
     for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
-    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 5);
+    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
   }
 }
 #endif
diff --git a/src/vdbe.c b/src/vdbe.c
index c8573f3d6..8a68602ff 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -161,12 +161,6 @@ int sqlite3_found_count = 0;
    if( ((P)->flags&MEM_Ephem)!=0 \
        && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}
 
-/*
-** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
-** P if required.
-*/
-#define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
-
 /* Return true if the cursor was opened using the OP_OpenSorter opcode. */
 #ifdef SQLITE_OMIT_MERGE_SORT
 # define isSorter(x) 0
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index f38d18559..26077b684 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -486,8 +486,10 @@ int sqlite3VdbeMemHandleBom(Mem *pMem);
 
 #ifndef SQLITE_OMIT_INCRBLOB
   int sqlite3VdbeMemExpandBlob(Mem *);
+  #define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
 #else
   #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
+  #define ExpandBlob(P) SQLITE_OK
 #endif
 
 #endif /* !defined(_VDBEINT_H_) */
diff --git a/src/vdbemem.c b/src/vdbemem.c
index 0c7859431..f8777a791 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -19,12 +19,6 @@
 #include "vdbeInt.h"
 
 /*
-** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
-** P if required.
-*/
-#define expandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
-
-/*
 ** If pMem is an object with a valid string representation, this routine
 ** ensures the internal encoding for the string representation is
 ** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
@@ -123,7 +117,7 @@ int sqlite3VdbeMemMakeWriteable(Mem *pMem){
   int f;
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
   assert( (pMem->flags&MEM_RowSet)==0 );
-  expandBlob(pMem);
+  ExpandBlob(pMem);
   f = pMem->flags;
   if( (f&(MEM_Str|MEM_Blob)) && pMem->z!=pMem->zMalloc ){
     if( sqlite3VdbeMemGrow(pMem, pMem->n + 2, 1) ){
@@ -960,7 +954,7 @@ const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
   }
   assert( (MEM_Blob>>3) == MEM_Str );
   pVal->flags |= (pVal->flags & MEM_Blob)>>3;
-  expandBlob(pVal);
+  ExpandBlob(pVal);
   if( pVal->flags&MEM_Str ){
     sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
     if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
diff --git a/src/wal.c b/src/wal.c
index b9d353220..db9ce5186 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -1727,7 +1727,7 @@ static int walCheckpoint(
       i64 nReq = ((i64)mxPage * szPage);
       rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
       if( rc==SQLITE_OK && nSize<nReq ){
-        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
+        sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
       }
     }
 
@@ -1843,7 +1843,9 @@ int sqlite3WalClose(
       );
       if( rc==SQLITE_OK ){
         int bPersist = -1;
-        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist);
+        sqlite3OsFileControlHint(
+            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
+        );
         if( bPersist!=1 ){
           /* Try to delete the WAL file if the checkpoint completed and
           ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
@@ -1864,7 +1866,9 @@ int sqlite3WalClose(
     walIndexClose(pWal, isDelete);
     sqlite3OsClose(pWal->pWalFd);
     if( isDelete ){
+      sqlite3BeginBenignMalloc();
       sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
+      sqlite3EndBenignMalloc();
     }
     WALTRACE(("WAL%p: closed\n", pWal));
     sqlite3_free((void *)pWal->apWiData);