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Comment:Remove the BtreeMutexArray object - use the Vdbe.btreeMask field to accomplish the same result. Add a generation counter to btree mutexes in order to assert that mutexes are never temporarily dropped over a range of instructions in order to do deadlock avoidance in some subroutine. Lock all btrees in any Vdbe program that uses OP_ParseSchema.
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SHA1: d81708f7d1eee399bfe76f6b8dac950a85dc2582
User & Date: drh 2011-04-04 00:14:43.936
Context
2011-04-04
03:27
Suppress unused parameter warnings in sqlite3VdbeEnter() and related routines. (check-in: f8e98ab306 user: drh tags: trunk)
00:14
Remove the BtreeMutexArray object - use the Vdbe.btreeMask field to accomplish the same result. Add a generation counter to btree mutexes in order to assert that mutexes are never temporarily dropped over a range of instructions in order to do deadlock avoidance in some subroutine. Lock all btrees in any Vdbe program that uses OP_ParseSchema. (check-in: d81708f7d1 user: drh tags: trunk)
2011-04-03
18:19
Make sure that the constant 1 is cast to yDbType before shifting to create an attached database mask. This check-in is a follow-up and fix to the [7aaf8772274422] change that increases the maximum number of attached databases from 30 to 62. (check-in: e2a09ea73c user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btmutex.c.
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}

/*
** Release the BtShared mutex associated with B-Tree handle p and
** clear the p->locked boolean.
*/
static void unlockBtreeMutex(Btree *p){

  assert( p->locked==1 );
  assert( sqlite3_mutex_held(p->pBt->mutex) );
  assert( sqlite3_mutex_held(p->db->mutex) );
  assert( p->db==p->pBt->db );


  sqlite3_mutex_leave(p->pBt->mutex);
  p->locked = 0;
}


















/*
** Enter a mutex on the given BTree object.
**
** If the object is not sharable, then no mutex is ever required
** and this routine is a no-op.  The underlying mutex is non-recursive.
** But we keep a reference count in Btree.wantToLock so the behavior







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}

/*
** Release the BtShared mutex associated with B-Tree handle p and
** clear the p->locked boolean.
*/
static void unlockBtreeMutex(Btree *p){
  BtShared *pBt = p->pBt;
  assert( p->locked==1 );
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( sqlite3_mutex_held(p->db->mutex) );
  assert( p->db==pBt->db );

  pBt->iMutexCounter++;
  sqlite3_mutex_leave(pBt->mutex);
  p->locked = 0;
}

#ifdef SQLITE_DEBUG
/*
** Return the number of times that the mutex has been exited for
** the given btree.
**
** This is a small circular counter that wraps around to zero on
** overflow.  It is used only for sanity checking - to verify that
** mutexes are held continously by asserting that the value of
** this counter at the beginning of a region is the same as at
** the end.
*/
u32 sqlite3BtreeMutexCounter(Btree *p){
  assert( p->locked==1 || p->sharable==0 );
  return p->pBt->iMutexCounter;
}
#endif

/*
** Enter a mutex on the given BTree object.
**
** If the object is not sharable, then no mutex is ever required
** and this routine is a no-op.  The underlying mutex is non-recursive.
** But we keep a reference count in Btree.wantToLock so the behavior
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  /* Unless the database is sharable and unlocked, then BtShared.db
  ** should already be set correctly. */
  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );

  if( !p->sharable ) return;
  p->wantToLock++;
  if( p->locked ) return;



















  /* In most cases, we should be able to acquire the lock we
  ** want without having to go throught the ascending lock
  ** procedure that follows.  Just be sure not to block.
  */
  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
    p->pBt->db = p->db;







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  /* Unless the database is sharable and unlocked, then BtShared.db
  ** should already be set correctly. */
  assert( (p->locked==0 && p->sharable) || p->pBt->db==p->db );

  if( !p->sharable ) return;
  p->wantToLock++;
  if( p->locked ) return;

  /* Increment the mutex counter on all locked btrees in the same
  ** database connection.  This simulates the unlocking that would
  ** occur on a worst-case mutex dead-lock avoidance scenario.
  */
#ifdef SQLITE_DEBUG
  {
    int ii;
    sqlite3 *db = p->db;
    Btree *pOther;
    for(ii=0; ii<db->nDb; ii++){
      if( ii==1 ) continue;
      pOther = db->aDb[ii].pBt;
      if( pOther==0 || pOther->sharable==0 || pOther->locked==0 ) continue;
      pOther->pBt->iMutexCounter++;
    }
  }
#endif

  /* In most cases, we should be able to acquire the lock we
  ** want without having to go throught the ascending lock
  ** procedure that follows.  Just be sure not to block.
  */
  if( sqlite3_mutex_try(p->pBt->mutex)==SQLITE_OK ){
    p->pBt->db = p->db;
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      return 0;
    }
  }
  return 1;
}
#endif /* NDEBUG */

/*
** Add a new Btree pointer to a BtreeMutexArray. 
** if the pointer can possibly be shared with
** another database connection.
**
** The pointers are kept in sorted order by pBtree->pBt.  That
** way when we go to enter all the mutexes, we can enter them
** in order without every having to backup and retry and without
** worrying about deadlock.
**
** The number of shared btrees will always be small (usually 0 or 1)
** so an insertion sort is an adequate algorithm here.
*/
void sqlite3BtreeMutexArrayInsert(BtreeMutexArray *pArray, Btree *pBtree){
  int i, j;
  BtShared *pBt;
  if( pBtree==0 || pBtree->sharable==0 ) return;
#ifndef NDEBUG
  {
    for(i=0; i<pArray->nMutex; i++){
      assert( pArray->aBtree[i]!=pBtree );
    }
  }
#endif
  assert( pArray->nMutex>=0 );
  assert( pArray->nMutex<ArraySize(pArray->aBtree)-1 );
  pBt = pBtree->pBt;
  for(i=0; i<pArray->nMutex; i++){
    assert( pArray->aBtree[i]!=pBtree );
    if( pArray->aBtree[i]->pBt>pBt ){
      for(j=pArray->nMutex; j>i; j--){
        pArray->aBtree[j] = pArray->aBtree[j-1];
      }
      pArray->aBtree[i] = pBtree;
      pArray->nMutex++;
      return;
    }
  }
  pArray->aBtree[pArray->nMutex++] = pBtree;
}

/*
** Enter the mutex of every btree in the array.  This routine is
** called at the beginning of sqlite3VdbeExec().  The mutexes are
** exited at the end of the same function.
*/
void sqlite3BtreeMutexArrayEnter(BtreeMutexArray *pArray){
  int i;
  for(i=0; i<pArray->nMutex; i++){
    Btree *p = pArray->aBtree[i];
    /* Some basic sanity checking */
    assert( i==0 || pArray->aBtree[i-1]->pBt<p->pBt );
    assert( !p->locked || p->wantToLock>0 );

    /* We should already hold a lock on the database connection */
    assert( sqlite3_mutex_held(p->db->mutex) );

    /* The Btree is sharable because only sharable Btrees are entered
    ** into the array in the first place. */
    assert( p->sharable );

    p->wantToLock++;
    if( !p->locked ){
      lockBtreeMutex(p);
    }
  }
}

/*
** Leave the mutex of every btree in the group.

*/
void sqlite3BtreeMutexArrayLeave(BtreeMutexArray *pArray){
  int i;
  for(i=0; i<pArray->nMutex; i++){
    Btree *p = pArray->aBtree[i];
    /* Some basic sanity checking */
    assert( i==0 || pArray->aBtree[i-1]->pBt<p->pBt );
    assert( p->locked );
    assert( p->wantToLock>0 );

    /* We should already hold a lock on the database connection */
    assert( sqlite3_mutex_held(p->db->mutex) );

    p->wantToLock--;
    if( p->wantToLock==0 ){
      unlockBtreeMutex(p);
    }
  }
}

#else
void sqlite3BtreeEnter(Btree *p){
  p->pBt->db = p->db;
}
void sqlite3BtreeEnterAll(sqlite3 *db){
  int i;
  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;







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      return 0;
    }
  }
  return 1;
}
#endif /* NDEBUG */









































#else /* SQLITE_THREADSAFE>0 above.  SQLITE_THREADSAFE==0 below */
/*











** The following are special cases for mutex enter routines for use


** in single threaded applications that use shared cache.  Except for



** these two routines, all mutex operations are no-ops in that case and






** are null #defines in btree.h.
**
** If shared cache is disabled, then all btree mutex routines, including
** the ones below, are no-ops and are null #defines in btree.h.
*/




















void sqlite3BtreeEnter(Btree *p){
  p->pBt->db = p->db;
}
void sqlite3BtreeEnterAll(sqlite3 *db){
  int i;
  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
Changes to src/btree.h.
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/*
** Forward declarations of structure
*/
typedef struct Btree Btree;
typedef struct BtCursor BtCursor;
typedef struct BtShared BtShared;
typedef struct BtreeMutexArray BtreeMutexArray;

/*
** This structure records all of the Btrees that need to hold
** a mutex before we enter sqlite3VdbeExec().  The Btrees are
** are placed in aBtree[] in order of aBtree[]->pBt.  That way,
** we can always lock and unlock them all quickly.
*/
struct BtreeMutexArray {
  int nMutex;
  Btree *aBtree[SQLITE_MAX_ATTACHED+1];
};


int sqlite3BtreeOpen(
  const char *zFilename,   /* Name of database file to open */
  sqlite3 *db,             /* Associated database connection */
  Btree **ppBtree,         /* Return open Btree* here */
  int flags,               /* Flags */







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/*
** Forward declarations of structure
*/
typedef struct Btree Btree;
typedef struct BtCursor BtCursor;
typedef struct BtShared BtShared;














int sqlite3BtreeOpen(
  const char *zFilename,   /* Name of database file to open */
  sqlite3 *db,             /* Associated database connection */
  Btree **ppBtree,         /* Return open Btree* here */
  int flags,               /* Flags */
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#endif

#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
  void sqlite3BtreeLeave(Btree*);
  void sqlite3BtreeEnterCursor(BtCursor*);
  void sqlite3BtreeLeaveCursor(BtCursor*);
  void sqlite3BtreeLeaveAll(sqlite3*);
  void sqlite3BtreeMutexArrayEnter(BtreeMutexArray*);
  void sqlite3BtreeMutexArrayLeave(BtreeMutexArray*);
  void sqlite3BtreeMutexArrayInsert(BtreeMutexArray*, Btree*);
#ifndef NDEBUG
  /* These routines are used inside assert() statements only. */
  int sqlite3BtreeHoldsMutex(Btree*);
  int sqlite3BtreeHoldsAllMutexes(sqlite3*);

#endif
#else

# define sqlite3BtreeLeave(X)

# define sqlite3BtreeEnterCursor(X)
# define sqlite3BtreeLeaveCursor(X)
# define sqlite3BtreeLeaveAll(X)
# define sqlite3BtreeMutexArrayEnter(X)
# define sqlite3BtreeMutexArrayLeave(X)
# define sqlite3BtreeMutexArrayInsert(X,Y)

# define sqlite3BtreeHoldsMutex(X) 1
# define sqlite3BtreeHoldsAllMutexes(X) 1
#endif


#endif /* _BTREE_H_ */







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#endif

#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
  void sqlite3BtreeLeave(Btree*);
  void sqlite3BtreeEnterCursor(BtCursor*);
  void sqlite3BtreeLeaveCursor(BtCursor*);
  void sqlite3BtreeLeaveAll(sqlite3*);



#ifndef NDEBUG
  /* These routines are used inside assert() statements only. */
  int sqlite3BtreeHoldsMutex(Btree*);
  int sqlite3BtreeHoldsAllMutexes(sqlite3*);
  u32 sqlite3BtreeMutexCounter(Btree*);
#endif
#else

# define sqlite3BtreeLeave(X)
# define sqlite3BtreeMutexCounter(X) 0
# define sqlite3BtreeEnterCursor(X)
# define sqlite3BtreeLeaveCursor(X)
# define sqlite3BtreeLeaveAll(X)




# define sqlite3BtreeHoldsMutex(X) 1
# define sqlite3BtreeHoldsAllMutexes(X) 1
#endif


#endif /* _BTREE_H_ */
Changes to src/btreeInt.h.
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  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
  u32 pageSize;         /* Total number of bytes on a page */
  u32 usableSize;       /* Number of usable bytes on each page */
  int nTransaction;     /* Number of open transactions (read + write) */
  u32 nPage;            /* Number of pages in the database */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this struct */
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  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 */
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure







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  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
  u32 pageSize;         /* Total number of bytes on a page */
  u32 usableSize;       /* Number of usable bytes on each page */
  int nTransaction;     /* Number of open transactions (read + write) */
  u32 nPage;            /* Number of pages in the database */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  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 */
  u16 iMutexCounter;    /* The number of mutex_leave(mutex) calls */
#endif
  u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
};

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
Changes to src/vdbe.c.
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#ifdef VDBE_PROFILE
  u64 start;                 /* CPU clock count at start of opcode */
  int origPc;                /* Program counter at start of opcode */
#endif
  /*** INSERT STACK UNION HERE ***/

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  sqlite3VdbeMutexArrayEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    goto no_mem;
  }
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  p->rc = SQLITE_OK;







|







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#ifdef VDBE_PROFILE
  u64 start;                 /* CPU clock count at start of opcode */
  int origPc;                /* Program counter at start of opcode */
#endif
  /*** INSERT STACK UNION HERE ***/

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  sqlite3VdbeEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    goto no_mem;
  }
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  p->rc = SQLITE_OK;
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  if( ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = pOp[-1].p4.pColl;
  }
  (*ctx.pFunc->xFunc)(&ctx, n, apVal); /* IMP: R-24505-23230 */

  if( db->mallocFailed ){
    /* Even though a malloc() has failed, the implementation of the
    ** user function may have called an sqlite3_result_XXX() function
    ** to return a value. The following call releases any resources
    ** associated with such a value.
    */
    sqlite3VdbeMemRelease(&ctx.s);
    goto no_mem;
  }












  /* If any auxiliary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.
  */
  if( ctx.pVdbeFunc ){
    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
    pOp->p4.pVdbeFunc = ctx.pVdbeFunc;







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  if( ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = pOp[-1].p4.pColl;
  }
  (*ctx.pFunc->xFunc)(&ctx, n, apVal); /* IMP: R-24505-23230 */
  sqlite3VdbeMutexResync(p);
  if( db->mallocFailed ){
    /* Even though a malloc() has failed, the implementation of the
    ** user function may have called an sqlite3_result_XXX() function
    ** to return a value. The following call releases any resources
    ** associated with such a value.
    */
    sqlite3VdbeMemRelease(&ctx.s);
    goto no_mem;
  }

  /* The app-defined function has done something that as caused this
  ** statement to expire.  (Perhaps the function called sqlite3_exec()
  ** with a CREATE TABLE statement.)
  */
#if 0
  if( p->expired ){
    rc = SQLITE_ABORT;
    break;
  }
#endif

  /* If any auxiliary data functions have been called by this user function,
  ** immediately call the destructor for any non-static values.
  */
  if( ctx.pVdbeFunc ){
    sqlite3VdbeDeleteAuxData(ctx.pVdbeFunc, pOp->p1);
    pOp->p4.pVdbeFunc = ctx.pVdbeFunc;
2646
2647
2648
2649
2650
2651
2652

2653
2654
2655
2656
2657
2658
2659
          if( rc!=SQLITE_OK ){
            goto abort_due_to_error;
          }
        }
        if( p1==SAVEPOINT_ROLLBACK && (db->flags&SQLITE_InternChanges)!=0 ){
          sqlite3ExpirePreparedStatements(db);
          sqlite3ResetInternalSchema(db, 0);

          db->flags = (db->flags | SQLITE_InternChanges);
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){







>







2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
          if( rc!=SQLITE_OK ){
            goto abort_due_to_error;
          }
        }
        if( p1==SAVEPOINT_ROLLBACK && (db->flags&SQLITE_InternChanges)!=0 ){
          sqlite3ExpirePreparedStatements(db);
          sqlite3ResetInternalSchema(db, 0);
          sqlite3VdbeMutexResync(p);
          db->flags = (db->flags | SQLITE_InternChanges);
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){
2936
2937
2938
2939
2940
2941
2942

2943
2944
2945
2946
2947
2948
2949
    ** discard the database schema, as the user code implementing the
    ** v-table would have to be ready for the sqlite3_vtab structure itself
    ** to be invalidated whenever sqlite3_step() is called from within 
    ** a v-table method.
    */
    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
      sqlite3ResetInternalSchema(db, pOp->p1);

    }

    p->expired = 1;
    rc = SQLITE_SCHEMA;
  }
  break;
}







>







2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
    ** discard the database schema, as the user code implementing the
    ** v-table would have to be ready for the sqlite3_vtab structure itself
    ** to be invalidated whenever sqlite3_step() is called from within 
    ** a v-table method.
    */
    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
      sqlite3ResetInternalSchema(db, pOp->p1);
      sqlite3VdbeMutexResync(p);
    }

    p->expired = 1;
    rc = SQLITE_SCHEMA;
  }
  break;
}
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643


4644



4645
4646


4647

4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {
  int iDb;
  const char *zMaster;
  char *zSql;
  InitData initData;

  iDb = pOp->p1;
  assert( iDb>=0 && iDb<db->nDb );

  /* When this opcode is invoked, it is guaranteed that the b-tree mutex
  ** is held and the schema is loaded for database iDb. However, at the 
  ** start of the sqlite3_exec() call below, SQLite will invoke 
  ** sqlite3BtreeEnterAll(). If all mutexes are not already held, the iDb 
  ** mutex may be temporarily released to avoid deadlock. If this happens, 
  ** then some other thread may delete the in-memory schema of database iDb 
  ** before the SQL statement runs. The schema will not be reloaded because 
  ** the db->init.busy flag is set. This can result in a "no such table: 
  ** sqlite_master" or "malformed database schema" error being returned to 
  ** the user. 
  **
  ** To avoid this, obtain all mutexes and check that no other thread has
  ** deleted the schema before calling sqlite3_exec(). If we find that the
  ** another thread has deleted the schema, there is no need to update it.
  ** The updated schema will be loaded from disk when it is next required.
  */


  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );



  assert( DbHasProperty(db, iDb, DB_SchemaLoaded) );
  sqlite3BtreeEnterAll(db);


  if( DbHasProperty(db, iDb, DB_SchemaLoaded) ){

    zMaster = SCHEMA_TABLE(iDb);
    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
       db->aDb[iDb].zName, zMaster, pOp->p4.z);
    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      assert( db->init.busy==0 );
      db->init.busy = 1;
      initData.rc = SQLITE_OK;
      assert( !db->mallocFailed );
      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
      if( rc==SQLITE_OK ) rc = initData.rc;
      sqlite3DbFree(db, zSql);
      db->init.busy = 0;
    }
  }
  sqlite3BtreeLeaveAll(db);
  if( rc==SQLITE_NOMEM ){
    goto no_mem;
  }
  break;  
}

#if !defined(SQLITE_OMIT_ANALYZE)








|
<
|
<
<
<
|
<
<
<
<
<
<
<
<
<
<
<

>
>
|
>
>
>
|
|
>
>
|
>




















<







4631
4632
4633
4634
4635
4636
4637
4638
4639

4640



4641











4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674

4675
4676
4677
4678
4679
4680
4681
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {
  int iDb;
  const char *zMaster;
  char *zSql;
  InitData initData;

  /* Any prepared statement that invokes this opcode will hold mutexes

  ** on every btree.  This is a prerequisite for invoking 



  ** sqlite3InitCallback().











  */
#ifdef SQLITE_DEBUG
  for(iDb=0; iDb<db->nDb; iDb++){
    assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
  }
#endif
  assert( p->btreeMask == ~(yDbMask)0 );


  iDb = pOp->p1;
  assert( iDb>=0 && iDb<db->nDb );
  assert( DbHasProperty(db, iDb, DB_SchemaLoaded) );
  /* Used to be a conditional */ {
    zMaster = SCHEMA_TABLE(iDb);
    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s ORDER BY rowid",
       db->aDb[iDb].zName, zMaster, pOp->p4.z);
    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      assert( db->init.busy==0 );
      db->init.busy = 1;
      initData.rc = SQLITE_OK;
      assert( !db->mallocFailed );
      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
      if( rc==SQLITE_OK ) rc = initData.rc;
      sqlite3DbFree(db, zSql);
      db->init.busy = 0;
    }
  }

  if( rc==SQLITE_NOMEM ){
    goto no_mem;
  }
  break;  
}

#if !defined(SQLITE_OMIT_ANALYZE)
5186
5187
5188
5189
5190
5191
5192

5193
5194
5195
5196












5197

5198
5199
5200
5201
5202
5203
5204
  if( ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>p->aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = pOp[-1].p4.pColl;
  }
  (ctx.pFunc->xStep)(&ctx, n, apVal); /* IMP: R-24505-23230 */

  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&ctx.s));
    rc = ctx.isError;
  }












  sqlite3VdbeMemRelease(&ctx.s);

  break;
}

/* Opcode: AggFinal P1 P2 * P4 *
**
** Execute the finalizer function for an aggregate.  P1 is
** the memory location that is the accumulator for the aggregate.







>




>
>
>
>
>
>
>
>
>
>
>
>

>







5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
  if( ctx.pFunc->flags & SQLITE_FUNC_NEEDCOLL ){
    assert( pOp>p->aOp );
    assert( pOp[-1].p4type==P4_COLLSEQ );
    assert( pOp[-1].opcode==OP_CollSeq );
    ctx.pColl = pOp[-1].p4.pColl;
  }
  (ctx.pFunc->xStep)(&ctx, n, apVal); /* IMP: R-24505-23230 */
  sqlite3VdbeMutexResync(p);
  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(&ctx.s));
    rc = ctx.isError;
  }

  /* The app-defined function has done something that as caused this
  ** statement to expire.  (Perhaps the function called sqlite3_exec()
  ** with a CREATE TABLE statement.)
  */
#if 0
  if( p->expired ){
    rc = SQLITE_ABORT;
    break;
  }
#endif

  sqlite3VdbeMemRelease(&ctx.s);

  break;
}

/* Opcode: AggFinal P1 P2 * P4 *
**
** Execute the finalizer function for an aggregate.  P1 is
** the memory location that is the accumulator for the aggregate.
5212
5213
5214
5215
5216
5217
5218

5219
5220


5221
5222
5223
5224
5225
5226
5227
*/
case OP_AggFinal: {
  Mem *pMem;
  assert( pOp->p1>0 && pOp->p1<=p->nMem );
  pMem = &aMem[pOp->p1];
  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
  rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);

  if( rc ){
    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(pMem));


  }
  sqlite3VdbeChangeEncoding(pMem, encoding);
  UPDATE_MAX_BLOBSIZE(pMem);
  if( sqlite3VdbeMemTooBig(pMem) ){
    goto too_big;
  }
  break;







>


>
>







5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
*/
case OP_AggFinal: {
  Mem *pMem;
  assert( pOp->p1>0 && pOp->p1<=p->nMem );
  pMem = &aMem[pOp->p1];
  assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
  rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
  sqlite3VdbeMutexResync(p);
  if( rc ){
    sqlite3SetString(&p->zErrMsg, db, "%s", sqlite3_value_text(pMem));
  }else if( p->expired ){
    rc = SQLITE_ABORT;
  }
  sqlite3VdbeChangeEncoding(pMem, encoding);
  UPDATE_MAX_BLOBSIZE(pMem);
  if( sqlite3VdbeMemTooBig(pMem) ){
    goto too_big;
  }
  break;
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
       || eNew==PAGER_JOURNALMODE_WAL
       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );

  /* This opcode is used in two places: PRAGMA journal_mode and ATTACH.
  ** In PRAGMA journal_mode, the sqlite3VdbeUsesBtree() routine is called
  ** when the statment is prepared and so p->aMutex.nMutex>0.  All mutexes
  ** are already acquired.  But when used in ATTACH, sqlite3VdbeUsesBtree()
  ** is not called when the statement is prepared because it requires the
  ** iDb index of the database as a parameter, and the database has not
  ** yet been attached so that index is unavailable.  We have to wait
  ** until runtime (now) to get the mutex on the newly attached database.
  ** No other mutexes are required by the ATTACH command so this is safe
  ** to do.
  */
  assert( (p->btreeMask & (((yDbMask)1)<<pOp->p1))!=0 || p->aMutex.nMutex==0 );
  if( p->aMutex.nMutex==0 ){
    /* This occurs right after ATTACH.  Get a mutex on the newly ATTACHed
    ** database. */
    sqlite3VdbeUsesBtree(p, pOp->p1);
    sqlite3VdbeMutexArrayEnter(p);
  }

  pBt = db->aDb[pOp->p1].pBt;
  pPager = sqlite3BtreePager(pBt);
  eOld = sqlite3PagerGetJournalMode(pPager);
  if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
  if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;







|








<
|



|







5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328

5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
       || eNew==PAGER_JOURNALMODE_WAL
       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );

  /* This opcode is used in two places: PRAGMA journal_mode and ATTACH.
  ** In PRAGMA journal_mode, the sqlite3VdbeUsesBtree() routine is called
  ** when the statement is prepared and so p->btreeMask!=0.  All mutexes
  ** are already acquired.  But when used in ATTACH, sqlite3VdbeUsesBtree()
  ** is not called when the statement is prepared because it requires the
  ** iDb index of the database as a parameter, and the database has not
  ** yet been attached so that index is unavailable.  We have to wait
  ** until runtime (now) to get the mutex on the newly attached database.
  ** No other mutexes are required by the ATTACH command so this is safe
  ** to do.
  */

  if( p->btreeMask==0 ){
    /* This occurs right after ATTACH.  Get a mutex on the newly ATTACHed
    ** database. */
    sqlite3VdbeUsesBtree(p, pOp->p1);
    sqlite3VdbeEnter(p);
  }

  pBt = db->aDb[pOp->p1].pBt;
  pPager = sqlite3BtreePager(pBt);
  eOld = sqlite3PagerGetJournalMode(pPager);
  if( eNew==PAGER_JOURNALMODE_QUERY ) eNew = eOld;
  if( !sqlite3PagerOkToChangeJournalMode(pPager) ) eNew = eOld;
5942
5943
5944
5945
5946
5947
5948
5949



5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
  p->rc = rc;
  testcase( sqlite3GlobalConfig.xLog!=0 );
  sqlite3_log(rc, "statement aborts at %d: [%s] %s", 
                   pc, p->zSql, p->zErrMsg);
  sqlite3VdbeHalt(p);
  if( rc==SQLITE_IOERR_NOMEM ) db->mallocFailed = 1;
  rc = SQLITE_ERROR;
  if( resetSchemaOnFault ) sqlite3ResetInternalSchema(db, 0);




  /* This is the only way out of this procedure.  We have to
  ** release the mutexes on btrees that were acquired at the
  ** top. */
vdbe_return:
  sqlite3BtreeMutexArrayLeave(&p->aMutex);
  return rc;

  /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
  ** is encountered.
  */
too_big:
  sqlite3SetString(&p->zErrMsg, db, "string or blob too big");







|
>
>
>





|







5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
  p->rc = rc;
  testcase( sqlite3GlobalConfig.xLog!=0 );
  sqlite3_log(rc, "statement aborts at %d: [%s] %s", 
                   pc, p->zSql, p->zErrMsg);
  sqlite3VdbeHalt(p);
  if( rc==SQLITE_IOERR_NOMEM ) db->mallocFailed = 1;
  rc = SQLITE_ERROR;
  if( resetSchemaOnFault ){
    sqlite3ResetInternalSchema(db, 0);
    sqlite3VdbeMutexResync(p);
  }

  /* This is the only way out of this procedure.  We have to
  ** release the mutexes on btrees that were acquired at the
  ** top. */
vdbe_return:
  sqlite3VdbeLeave(p);
  return rc;

  /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
  ** is encountered.
  */
too_big:
  sqlite3SetString(&p->zErrMsg, db, "string or blob too big");
Changes to src/vdbeInt.h.
299
300
301
302
303
304
305

306
307
308
309
310
311
312
313
314
315
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  u8 usesStmtJournal;     /* True if uses a statement journal */
  u8 readOnly;            /* True for read-only statements */
  u8 isPrepareV2;         /* True if prepared with prepare_v2() */
  int nChange;            /* Number of db changes made since last reset */
  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */

  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
  int aCounter[3];        /* Counters used by sqlite3_stmt_status() */
  BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
#ifndef SQLITE_OMIT_TRACE
  i64 startTime;          /* Time when query started - used for profiling */
#endif
  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */







>


<







299
300
301
302
303
304
305
306
307
308

309
310
311
312
313
314
315
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  u8 usesStmtJournal;     /* True if uses a statement journal */
  u8 readOnly;            /* True for read-only statements */
  u8 isPrepareV2;         /* True if prepared with prepare_v2() */
  int nChange;            /* Number of db changes made since last reset */
  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
  u32 iMutexCounter;      /* Mutex counter upon sqlite3VdbeEnter() */
  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
  int aCounter[3];        /* Counters used by sqlite3_stmt_status() */

#ifndef SQLITE_OMIT_TRACE
  i64 startTime;          /* Time when query started - used for profiling */
#endif
  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
383
384
385
386
387
388
389



390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
void sqlite3VdbeMemStoreType(Mem *pMem);




#ifdef SQLITE_DEBUG
void sqlite3VdbeMemPrepareToChange(Vdbe*,Mem*);
#endif

#ifndef SQLITE_OMIT_FOREIGN_KEY
int sqlite3VdbeCheckFk(Vdbe *, int);
#else
# define sqlite3VdbeCheckFk(p,i) 0
#endif

#ifndef SQLITE_OMIT_SHARED_CACHE
void sqlite3VdbeMutexArrayEnter(Vdbe *p);
#else
# define sqlite3VdbeMutexArrayEnter(p)
#endif

int sqlite3VdbeMemTranslate(Mem*, u8);
#ifdef SQLITE_DEBUG
  void sqlite3VdbePrintSql(Vdbe*);
  void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
#endif
int sqlite3VdbeMemHandleBom(Mem *pMem);








>
>
>











<
<
<
<
<
<







383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403






404
405
406
407
408
409
410
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
void sqlite3VdbeMemStoreType(Mem *pMem);
void sqlite3VdbeEnter(Vdbe*);
void sqlite3VdbeLeave(Vdbe*);
void sqlite3VdbeMutexResync(Vdbe*);

#ifdef SQLITE_DEBUG
void sqlite3VdbeMemPrepareToChange(Vdbe*,Mem*);
#endif

#ifndef SQLITE_OMIT_FOREIGN_KEY
int sqlite3VdbeCheckFk(Vdbe *, int);
#else
# define sqlite3VdbeCheckFk(p,i) 0
#endif







int sqlite3VdbeMemTranslate(Mem*, u8);
#ifdef SQLITE_DEBUG
  void sqlite3VdbePrintSql(Vdbe*);
  void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
#endif
int sqlite3VdbeMemHandleBom(Mem *pMem);

Changes to src/vdbeaux.c.
153
154
155
156
157
158
159





160
161
162
163
164
165
166
  pOp->p5 = 0;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3 = p3;
  pOp->p4.p = 0;
  pOp->p4type = P4_NOTUSED;
  p->expired = 0;





#ifdef SQLITE_DEBUG
  pOp->zComment = 0;
  if( sqlite3VdbeAddopTrace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
#endif
#ifdef VDBE_PROFILE
  pOp->cycles = 0;
  pOp->cnt = 0;







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  pOp->p5 = 0;
  pOp->p1 = p1;
  pOp->p2 = p2;
  pOp->p3 = p3;
  pOp->p4.p = 0;
  pOp->p4type = P4_NOTUSED;
  p->expired = 0;
  if( op==OP_ParseSchema ){
    /* Any program that uses the OP_ParseSchema opcode needs to lock
    ** all btrees. */
    p->btreeMask = ~(yDbMask)0;
  }
#ifdef SQLITE_DEBUG
  pOp->zComment = 0;
  if( sqlite3VdbeAddopTrace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
#endif
#ifdef VDBE_PROFILE
  pOp->cycles = 0;
  pOp->cnt = 0;
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** returned program.
*/
VdbeOp *sqlite3VdbeTakeOpArray(Vdbe *p, int *pnOp, int *pnMaxArg){
  VdbeOp *aOp = p->aOp;
  assert( aOp && !p->db->mallocFailed );

  /* Check that sqlite3VdbeUsesBtree() was not called on this VM */
  assert( p->aMutex.nMutex==0 );

  resolveP2Values(p, pnMaxArg);
  *pnOp = p->nOp;
  p->aOp = 0;
  return aOp;
}








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** returned program.
*/
VdbeOp *sqlite3VdbeTakeOpArray(Vdbe *p, int *pnOp, int *pnMaxArg){
  VdbeOp *aOp = p->aOp;
  assert( aOp && !p->db->mallocFailed );

  /* Check that sqlite3VdbeUsesBtree() was not called on this VM */
  assert( p->btreeMask==0 );

  resolveP2Values(p, pnMaxArg);
  *pnOp = p->nOp;
  p->aOp = 0;
  return aOp;
}

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  return zP4;
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**
** The prepared statement has to know in advance which Btree objects
** will be used so that it can acquire mutexes on them all in sorted
** order (via sqlite3VdbeMutexArrayEnter().  Mutexes are acquired
** in order (and released in reverse order) to avoid deadlocks.
*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){
  yDbMask mask;
  assert( i>=0 && i<p->db->nDb && i<sizeof(yDbMask)*8 );
  assert( i<(int)sizeof(p->btreeMask)*8 );
  mask = ((yDbMask)1)<<i;

  if( (p->btreeMask & mask)==0 ){









    p->btreeMask |= mask;





    sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);

  }


}























































































#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
/*
** Print a single opcode.  This routine is used for debugging only.
*/
void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
  char *zP4;







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  return zP4;
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**
** The prepared statements need to know in advance the complete set of
** attached databases that they will be using.  A mask of these databases
** is maintained in p->btreeMask and is used for locking and other purposes.

*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){

  assert( i>=0 && i<p->db->nDb && i<sizeof(yDbMask)*8 );
  assert( i<(int)sizeof(p->btreeMask)*8 );
  p->btreeMask |= ((yDbMask)1)<<i;
}

/*
** Compute the sum of all mutex counters for all btrees in the
** given prepared statement.
*/
#ifndef SQLITE_OMIT_SHARED_CACHE
static u32 mutexCounterSum(Vdbe *p){
  u32 cntSum = 0;
#ifdef SQLITE_DEBUG
  int i;
  yDbMask mask;
  sqlite3 *db = p->db;
  Db *aDb = db->aDb;
  int nDb = db->nDb;
  for(i=0, mask=1; i<nDb; i++, mask += mask){
    if( i!=1 && (mask & p->btreeMask)!=0 && ALWAYS(aDb[i].pBt!=0) ){
      cntSum += sqlite3BtreeMutexCounter(aDb[i].pBt);
    }
  }
#endif
  return cntSum;
}
#endif

/*
** If SQLite is compiled to support shared-cache mode and to be threadsafe,
** this routine obtains the mutex associated with each BtShared structure
** that may be accessed by the VM passed as an argument. In doing so it also
** sets the BtShared.db member of each of the BtShared structures, ensuring
** that the correct busy-handler callback is invoked if required.
**
** If SQLite is not threadsafe but does support shared-cache mode, then
** sqlite3BtreeEnter() is invoked to set the BtShared.db variables
** of all of BtShared structures accessible via the database handle 
** associated with the VM.
**
** If SQLite is not threadsafe and does not support shared-cache mode, this
** function is a no-op.
**
** The p->btreeMask field is a bitmask of all btrees that the prepared 
** statement p will ever use.  Let N be the number of bits in p->btreeMask
** corresponding to btrees that use shared cache.  Then the runtime of
** this routine is N*N.  But as N is rarely more than 1, this should not
** be a problem.
*/
void sqlite3VdbeEnter(Vdbe *p){
#ifndef SQLITE_OMIT_SHARED_CACHE
  int i;
  yDbMask mask;
  sqlite3 *db = p->db;
  Db *aDb = db->aDb;
  int nDb = db->nDb;
  for(i=0, mask=1; i<nDb; i++, mask += mask){
    if( i!=1 && (mask & p->btreeMask)!=0 && ALWAYS(aDb[i].pBt!=0) ){
      sqlite3BtreeEnter(aDb[i].pBt);
    }
  }
  p->iMutexCounter = mutexCounterSum(p);
#endif
}

/*
** Unlock all of the btrees previously locked by a call to sqlite3VdbeEnter().
*/
void sqlite3VdbeLeave(Vdbe *p){
#ifndef SQLITE_OMIT_SHARED_CACHE
  int i;
  yDbMask mask;
  sqlite3 *db = p->db;
  Db *aDb = db->aDb;
  int nDb = db->nDb;

  /* Assert that the all mutexes have been held continously since
  ** the most recent sqlite3VdbeEnter() or sqlite3VdbeMutexResync().
  */
  assert( mutexCounterSum(p) == p->iMutexCounter );

  for(i=0, mask=1; i<nDb; i++, mask += mask){
    if( i!=1 && (mask & p->btreeMask)!=0 && ALWAYS(aDb[i].pBt!=0) ){
      sqlite3BtreeLeave(aDb[i].pBt);
    }
  }
#endif
}

/*
** Recompute the sum of the mutex counters on all btrees used by the
** prepared statement p.
**
** Call this routine while holding a sqlite3VdbeEnter() after doing something
** that might cause one or more of the individual mutexes held by the
** prepared statement to be released.  Calling sqlite3BtreeEnter() on 
** any BtShared mutex which is not used by the prepared statement is one
** way to cause one or more of the mutexes in the prepared statement
** to be temporarily released.  The anti-deadlocking logic in
** sqlite3BtreeEnter() can cause mutexes to be released temporarily then
** reacquired.
**
** Calling this routine is an acknowledgement that some of the individual
** mutexes in the prepared statement might have been released and reacquired.
** So checks to verify that mutex-protected content did not change
** unexpectedly should accompany any call to this routine.
*/
void sqlite3VdbeMutexResync(Vdbe *p){
#if !defined(SQLITE_OMIT_SHARED_CACHE) && defined(SQLITE_DEBUG)
  p->iMutexCounter = mutexCounterSum(p);
#endif
}

#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
/*
** Print a single opcode.  This routine is used for debugging only.
*/
void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
  char *zP4;
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    if( eOp==SAVEPOINT_ROLLBACK ){
      db->nDeferredCons = p->nStmtDefCons;
    }
  }
  return rc;
}

/*
** If SQLite is compiled to support shared-cache mode and to be threadsafe,
** this routine obtains the mutex associated with each BtShared structure
** that may be accessed by the VM passed as an argument. In doing so it
** sets the BtShared.db member of each of the BtShared structures, ensuring
** that the correct busy-handler callback is invoked if required.
**
** If SQLite is not threadsafe but does support shared-cache mode, then
** sqlite3BtreeEnterAll() is invoked to set the BtShared.db variables
** of all of BtShared structures accessible via the database handle 
** associated with the VM. Of course only a subset of these structures
** will be accessed by the VM, and we could use Vdbe.btreeMask to figure
** that subset out, but there is no advantage to doing so.
**
** If SQLite is not threadsafe and does not support shared-cache mode, this
** function is a no-op.
*/
#ifndef SQLITE_OMIT_SHARED_CACHE
void sqlite3VdbeMutexArrayEnter(Vdbe *p){
#if SQLITE_THREADSAFE
  sqlite3BtreeMutexArrayEnter(&p->aMutex);
#else
  sqlite3BtreeEnterAll(p->db);
#endif
}
#endif

/*
** This function is called when a transaction opened by the database 
** handle associated with the VM passed as an argument is about to be 
** committed. If there are outstanding deferred foreign key constraint
** violations, return SQLITE_ERROR. Otherwise, SQLITE_OK.
**
** If there are outstanding FK violations and this function returns 







<
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<







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    if( eOp==SAVEPOINT_ROLLBACK ){
      db->nDeferredCons = p->nStmtDefCons;
    }
  }
  return rc;
}




























/*
** This function is called when a transaction opened by the database 
** handle associated with the VM passed as an argument is about to be 
** committed. If there are outstanding deferred foreign key constraint
** violations, return SQLITE_ERROR. Otherwise, SQLITE_OK.
**
** If there are outstanding FK violations and this function returns 
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  /* No commit or rollback needed if the program never started */
  if( p->pc>=0 ){
    int mrc;   /* Primary error code from p->rc */
    int eStatementOp = 0;
    int isSpecialError;            /* Set to true if a 'special' error */

    /* Lock all btrees used by the statement */
    sqlite3VdbeMutexArrayEnter(p);

    /* Check for one of the special errors */
    mrc = p->rc & 0xff;
    assert( p->rc!=SQLITE_IOERR_BLOCKED );  /* This error no longer exists */
    isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
    if( isSpecialError ){







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  /* No commit or rollback needed if the program never started */
  if( p->pc>=0 ){
    int mrc;   /* Primary error code from p->rc */
    int eStatementOp = 0;
    int isSpecialError;            /* Set to true if a 'special' error */

    /* Lock all btrees used by the statement */
    sqlite3VdbeEnter(p);

    /* Check for one of the special errors */
    mrc = p->rc & 0xff;
    assert( p->rc!=SQLITE_IOERR_BLOCKED );  /* This error no longer exists */
    isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
    if( isSpecialError ){
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     && db->autoCommit 
     && db->writeVdbeCnt==(p->readOnly==0) 
    ){
      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
        rc = sqlite3VdbeCheckFk(p, 1);
        if( rc!=SQLITE_OK ){
          if( NEVER(p->readOnly) ){
            sqlite3BtreeMutexArrayLeave(&p->aMutex);
            return SQLITE_ERROR;
          }
          rc = SQLITE_CONSTRAINT;
        }else{ 
          /* The auto-commit flag is true, the vdbe program was successful 
          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
          ** key constraints to hold up the transaction. This means a commit 
          ** is required. */
          rc = vdbeCommit(db, p);
        }
        if( rc==SQLITE_BUSY && p->readOnly ){
          sqlite3BtreeMutexArrayLeave(&p->aMutex);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db);
        }else{
          db->nDeferredCons = 0;
          sqlite3CommitInternalChanges(db);







|











|







2187
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     && db->autoCommit 
     && db->writeVdbeCnt==(p->readOnly==0) 
    ){
      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
        rc = sqlite3VdbeCheckFk(p, 1);
        if( rc!=SQLITE_OK ){
          if( NEVER(p->readOnly) ){
            sqlite3VdbeLeave(p);
            return SQLITE_ERROR;
          }
          rc = SQLITE_CONSTRAINT;
        }else{ 
          /* The auto-commit flag is true, the vdbe program was successful 
          ** or hit an 'OR FAIL' constraint and there are no deferred foreign
          ** key constraints to hold up the transaction. This means a commit 
          ** is required. */
          rc = vdbeCommit(db, p);
        }
        if( rc==SQLITE_BUSY && p->readOnly ){
          sqlite3VdbeLeave(p);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db);
        }else{
          db->nDeferredCons = 0;
          sqlite3CommitInternalChanges(db);
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    /* Rollback or commit any schema changes that occurred. */
    if( p->rc!=SQLITE_OK && db->flags&SQLITE_InternChanges ){
      sqlite3ResetInternalSchema(db, 0);
      db->flags = (db->flags | SQLITE_InternChanges);
    }

    /* Release the locks */

    sqlite3BtreeMutexArrayLeave(&p->aMutex);
  }

  /* We have successfully halted and closed the VM.  Record this fact. */
  if( p->pc>=0 ){
    db->activeVdbeCnt--;
    if( !p->readOnly ){
      db->writeVdbeCnt--;







>
|







2271
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    /* Rollback or commit any schema changes that occurred. */
    if( p->rc!=SQLITE_OK && db->flags&SQLITE_InternChanges ){
      sqlite3ResetInternalSchema(db, 0);
      db->flags = (db->flags | SQLITE_InternChanges);
    }

    /* Release the locks */
    sqlite3VdbeMutexResync(p);
    sqlite3VdbeLeave(p);
  }

  /* We have successfully halted and closed the VM.  Record this fact. */
  if( p->pc>=0 ){
    db->activeVdbeCnt--;
    if( !p->readOnly ){
      db->writeVdbeCnt--;