SQLite

** is happening when it is supposed to.
*/
int sqlite3_xferopt_count;
#endif /* SQLITE_TEST */


#ifndef SQLITE_OMIT_XFER_OPT
/*
** Check to collation names to see if they are compatible.
*/
static int xferCompatibleCollation(const char *z1, const char *z2){
  if( z1==0 ){
    return z2==0;
  }
  if( z2==0 ){
    return 0;
  }
  return sqlite3StrICmp(z1, z2)==0;
}


/*
** Check to see if index pSrc is compatible as a source of data
** for index pDest in an insert transfer optimization.  The rules
** for a compatible index:
**
**    *   The index is over the same set of columns
**    *   The same DESC and ASC markings occurs on all columns

                             pDest->aColExpr->a[i].pExpr, -1)!=0 ){
        return 0;   /* Different expressions in the index */
      }
    }
    if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
      return 0;   /* Different sort orders */
    }
    if( !xferCompatibleCollation(pSrc->azColl[i],pDest->azColl[i]) ){
      return 0;   /* Different collating sequences */
    }
  }
  if( sqlite3ExprCompare(pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
    return 0;     /* Different WHERE clauses */
  }

    ){
      return 0;    /* Neither table may have __hidden__ columns */
    }
#endif
    if( pDestCol->affinity!=pSrcCol->affinity ){
      return 0;    /* Affinity must be the same on all columns */
    }
    if( !xferCompatibleCollation(pDestCol->zColl, pSrcCol->zColl) ){
      return 0;    /* Collating sequence must be the same on all columns */
    }
    if( pDestCol->notNull && !pSrcCol->notNull ){
      return 0;    /* tab2 must be NOT NULL if tab1 is */
    }
    /* Default values for second and subsequent columns need to match. */
    if( i>0