if( p->db ){
      zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
    }else{
      zNew = sqlite3_realloc64(zOld, p->nAlloc);
    }
    if( zNew ){
      assert( p->zText!=0 || p->nChar==0 );
      if( zOld==0 && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
      p->zText = zNew;
      p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
    }else{
      sqlite3StrAccumReset(p);
      setStrAccumError(p, STRACCUM_NOMEM);
      return 0;
    }

    if( p->db ){
      zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
    }else{
      zNew = sqlite3_realloc64(zOld, p->nAlloc);
    }
    if( zNew ){
      assert( p->zText!=0 || p->nChar==0 );
      if( p->zText==p->zBase && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
      p->zText = zNew;
      p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
    }else{
      sqlite3StrAccumReset(p);
      setStrAccumError(p, STRACCUM_NOMEM);
      return 0;
    }

    Tcl_WrongNumArgs(interp, 1, objv, "SCRIPT");
    return TCL_ERROR;
  }
  if( logcallback.pObj ){
    Tcl_DecrRefCount(logcallback.pObj);
    logcallback.pObj = 0;
    logcallback.pInterp = 0;
    sqlite3_config(SQLITE_CONFIG_LOG, 0, 0);
  }
  if( objc>1 ){
    logcallback.pObj = objv[1];
    Tcl_IncrRefCount(logcallback.pObj);
    logcallback.pInterp = interp;
    sqlite3_config(SQLITE_CONFIG_LOG, xLogcallback, 0);
  }
  return TCL_OK;
}

/*
**     tcl_objproc COMMANDNAME ARGS...
**

    Tcl_WrongNumArgs(interp, 1, objv, "SCRIPT");
    return TCL_ERROR;
  }
  if( logcallback.pObj ){
    Tcl_DecrRefCount(logcallback.pObj);
    logcallback.pObj = 0;
    logcallback.pInterp = 0;
    sqlite3_config(SQLITE_CONFIG_LOG, (void*)0, (void*)0);
  }
  if( objc>1 ){
    logcallback.pObj = objv[1];
    Tcl_IncrRefCount(logcallback.pObj);
    logcallback.pInterp = interp;
    sqlite3_config(SQLITE_CONFIG_LOG, xLogcallback, (void*)0);
  }
  return TCL_OK;
}

/*
**     tcl_objproc COMMANDNAME ARGS...
**

    ** a zeroed allocator then calling GETMALLOC. */
    memset(&m2, 0, sizeof(m2));
    sqlite3_config(SQLITE_CONFIG_MALLOC, &m2);
    sqlite3_config(SQLITE_CONFIG_GETMALLOC, &m2);
    assert( memcmp(&m2, &memfault.m, sizeof(m2))==0 );

    rc = sqlite3_config(SQLITE_CONFIG_MALLOC, &memfault.m);
    sqlite3_test_control(SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS, 0, 0);

  }

  if( rc==SQLITE_OK ){
    memfault.isInstalled = 1;
  }
  return rc;
}

    ** a zeroed allocator then calling GETMALLOC. */
    memset(&m2, 0, sizeof(m2));
    sqlite3_config(SQLITE_CONFIG_MALLOC, &m2);
    sqlite3_config(SQLITE_CONFIG_GETMALLOC, &m2);
    assert( memcmp(&m2, &memfault.m, sizeof(m2))==0 );

    rc = sqlite3_config(SQLITE_CONFIG_MALLOC, &memfault.m);
    sqlite3_test_control(SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS,
        (void*)0, (void*)0);
  }

  if( rc==SQLITE_OK ){
    memfault.isInstalled = 1;
  }
  return rc;
}

** NULL, it means that memory space has already been allocated and that
** this routine should not allocate any new memory.  When pBuf is not
** NULL simply return pBuf.  Only allocate new memory space when pBuf
** is NULL.
**
** nByte is the number of bytes of space needed.
**
** *ppFrom points to available space and pEnd points to the end of the
** available space.  When space is allocated, *ppFrom is advanced past
** the end of the allocated space.
**
** *pnByte is a counter of the number of bytes of space that have failed
** to allocate.  If there is insufficient space in *ppFrom to satisfy the
** request, then increment *pnByte by the amount of the request.
*/
static void *allocSpace(
  void *pBuf,          /* Where return pointer will be stored */
  int nByte,           /* Number of bytes to allocate */

  u8 **ppFrom,         /* IN/OUT: Allocate from *ppFrom */
  u8 *pEnd,            /* Pointer to 1 byte past the end of *ppFrom buffer */
  int *pnByte          /* If allocation cannot be made, increment *pnByte */
){
  assert( EIGHT_BYTE_ALIGNMENT(*ppFrom) );
  if( pBuf ) return pBuf;
  nByte = ROUND8(nByte);
  if( &(*ppFrom)[nByte] <= pEnd ){
    pBuf = (void*)*ppFrom;
    *ppFrom += nByte;

  }else{
    *pnByte += nByte;
  }


  return pBuf;
}

/*
** Rewind the VDBE back to the beginning in preparation for
** running it.
*/
................................................................................
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Number of arguments in subprograms */
  int nOnce;                     /* Number of OP_Once instructions */
  int n;                         /* Loop counter */

  u8 *zCsr;                      /* Memory available for allocation */
  u8 *zEnd;                      /* First byte past allocated memory */
  int nByte;                     /* How much extra memory is needed */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( pParse==p->pParse );
................................................................................
  */
  nMem += nCursor;

  /* Allocate space for memory registers, SQL variables, VDBE cursors and 
  ** an array to marshal SQL function arguments in.
  */
  zCsr = (u8*)&p->aOp[p->nOp];            /* Memory avaliable for allocation */
  zEnd = (u8*)&p->aOp[pParse->nOpAlloc];  /* First byte past end of zCsr[] */


  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain && nMem<10 ){
    nMem = 10;
  }
  memset(zCsr, 0, zEnd-zCsr);
  zCsr += (zCsr - (u8*)0)&7;
  assert( EIGHT_BYTE_ALIGNMENT(zCsr) );
  p->expired = 0;

  /* Memory for registers, parameters, cursor, etc, is allocated in two
  ** passes.  On the first pass, we try to reuse unused space at the 
  ** end of the opcode array.  If we are unable to satisfy all memory
................................................................................
  **
  ** This two-pass approach that reuses as much memory as possible from
  ** the leftover space at the end of the opcode array can significantly
  ** reduce the amount of memory held by a prepared statement.
  */
  do {
    nByte = 0;
    p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), &zCsr, zEnd, &nByte);
    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), &zCsr, zEnd, &nByte);
    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                          &zCsr, zEnd, &nByte);
    p->aOnceFlag = allocSpace(p->aOnceFlag, nOnce, &zCsr, zEnd, &nByte);
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
    p->anExec = allocSpace(p->anExec, p->nOp*sizeof(i64), &zCsr, zEnd, &nByte);
#endif
    if( nByte ){
      p->pFree = sqlite3DbMallocZero(db, nByte);
    }
    zCsr = p->pFree;
    zEnd = &zCsr[nByte];
  }while( nByte && !db->mallocFailed );

  p->nCursor = nCursor;
  p->nOnceFlag = nOnce;
  if( p->aVar ){
    p->nVar = (ynVar)nVar;
    for(n=0; n<nVar; n++){

** NULL, it means that memory space has already been allocated and that
** this routine should not allocate any new memory.  When pBuf is not
** NULL simply return pBuf.  Only allocate new memory space when pBuf
** is NULL.
**
** nByte is the number of bytes of space needed.
**
** pFrom points to *pnFrom bytes of available space.  New space is allocated
** from the end of the pFrom buffer and *pnFrom is decremented.

**
** *pnNeeded is a counter of the number of bytes of space that have failed
** to allocate.  If there is insufficient space in pFrom to satisfy the
** request, then increment *pnNeeded by the amount of the request.
*/
static void *allocSpace(
  void *pBuf,          /* Where return pointer will be stored */
  int nByte,           /* Number of bytes to allocate */
  u8 *pFrom,           /* Memory available for allocation */
  int *pnFrom,         /* IN/OUT: Space available at pFrom */

  int *pnNeeded        /* If allocation cannot be made, increment *pnByte */
){
  assert( EIGHT_BYTE_ALIGNMENT(pFrom) );
  if( pBuf==0 ){
    nByte = ROUND8(nByte);
    if( nByte <= *pnFrom ){

      *pnFrom -= nByte;
      pBuf = &pFrom[*pnFrom];
    }else{
      *pnNeeded += nByte;
    }
  }
  assert( EIGHT_BYTE_ALIGNMENT(pBuf) );
  return pBuf;
}

/*
** Rewind the VDBE back to the beginning in preparation for
** running it.
*/
................................................................................
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Number of arguments in subprograms */
  int nOnce;                     /* Number of OP_Once instructions */
  int n;                         /* Loop counter */
  int nFree;                     /* Available free space */
  u8 *zCsr;                      /* Memory available for allocation */

  int nByte;                     /* How much extra memory is needed */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( pParse==p->pParse );
................................................................................
  */
  nMem += nCursor;

  /* Allocate space for memory registers, SQL variables, VDBE cursors and 
  ** an array to marshal SQL function arguments in.
  */
  zCsr = (u8*)&p->aOp[p->nOp];            /* Memory avaliable for allocation */
  assert( pParse->nOpAlloc*sizeof(Op) <= 0x7fffff00 );
  nFree = (pParse->nOpAlloc - p->nOp)*sizeof(p->aOp[0]); /* Available space */

  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain && nMem<10 ){
    nMem = 10;
  }
  memset(zCsr, 0, nFree);
  zCsr += (zCsr - (u8*)0)&7;
  assert( EIGHT_BYTE_ALIGNMENT(zCsr) );
  p->expired = 0;

  /* Memory for registers, parameters, cursor, etc, is allocated in two
  ** passes.  On the first pass, we try to reuse unused space at the 
  ** end of the opcode array.  If we are unable to satisfy all memory
................................................................................
  **
  ** This two-pass approach that reuses as much memory as possible from
  ** the leftover space at the end of the opcode array can significantly
  ** reduce the amount of memory held by a prepared statement.
  */
  do {
    nByte = 0;
    p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), zCsr, &nFree, &nByte);
    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), zCsr, &nFree, &nByte);
    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), zCsr, &nFree, &nByte);
    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), zCsr, &nFree, &nByte);
    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                          zCsr, &nFree, &nByte);
    p->aOnceFlag = allocSpace(p->aOnceFlag, nOnce, zCsr, &nFree, &nByte);
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
    p->anExec = allocSpace(p->anExec, p->nOp*sizeof(i64), zCsr, &nFree, &nByte);
#endif
    if( nByte ){
      p->pFree = sqlite3DbMallocZero(db, nByte);
    }
    zCsr = p->pFree;
    nFree = nByte;
  }while( nByte && !db->mallocFailed );

  p->nCursor = nCursor;
  p->nOnceFlag = nOnce;
  if( p->aVar ){
    p->nVar = (ynVar)nVar;
    for(n=0; n<nVar; n++){