SQLite

Check-in [bcb4f26247]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Further tweaks to the ORDER BY optimizer, to fix a bug and to get the optimizer to recognize some additional cases.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | qp-enhancements
Files: files | file ages | folders
SHA1: bcb4f262476193cfb17818d8c62bab528dddeef9
User & Date: drh 2012-10-08 20:27:35.617
Context
2012-10-08
21:01
All test cases (veryquick.tcl and min.rc) pass. A few branch operations in ORDER BY optimization logic are untested by min.rc. (Closed-Leaf check-in: 8314fd6078 user: drh tags: qp-enhancements)
20:27
Further tweaks to the ORDER BY optimizer, to fix a bug and to get the optimizer to recognize some additional cases. (check-in: bcb4f26247 user: drh tags: qp-enhancements)
19:41
Bug fixes in the ORDER BY optimizer. (check-in: 301bbee404 user: drh tags: qp-enhancements)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/where.c.
︙
2904
2905
2906
2907
2908
2909
2910
2911


2912
2913

2914
2915
2916
2917
2918
2919
2920
2921

2904
2905
2906
2907
2908
2909
2910

2911
2912
2913

2914

2915
2916
2917
2918
2919
2920
2921








-
+
+

-
+
-








    ** if there are any X= or X IS NULL constraints in the WHERE clause. */
    pConstraint = findTerm(p->pWC, base, iColumn, p->notReady,
                           WO_EQ|WO_ISNULL|WO_IN, pIdx);
    if( pConstraint==0 ){
      isEq = 0;
    }else if( pConstraint->eOperator==WO_IN ){
      break;
    }else if( pConstraint->prereqRight==0 ){
    }else if( pConstraint->eOperator==WO_ISNULL ){
      uniqueNotNull = 0;
      isEq = 1;
    }else if( pConstraint->eOperator==WO_ISNULL ){
    }else if( pConstraint->prereqRight==0 ){
      uniqueNotNull = 0;
      isEq = 1;
    }else{
      Expr *pRight = pConstraint->pExpr->pRight;
      if( pRight->op==TK_COLUMN ){
        WHERETRACE(("       .. isOrderedColumn(tab=%d,col=%d)",
                    pRight->iTable, pRight->iColumn));
        isEq = isOrderedColumn(p, pRight->iTable, pRight->iColumn);
︙
2931
2932
2933
2934
2935
2936
2937

2938
2939
2940
2941





2942
2943
2944
2945
2946
2947
2948

2949
2950
2951
2952
2953
2954
2955

2931
2932
2933
2934
2935
2936
2937
2938




2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949

2950
2951
2952
2953
2954
2955
2956
2957








+
-
-
-
-
+
+
+
+
+






-
+








    assert( iSortOrder==0 || iSortOrder==1 );
    if( !isMatch ){
      if( isEq==0 ){
        break;
      }else{
        continue;
      }
    }else if( isEq!=1 ){
    }else if( sortOrder==2 ){
      sortOrder = termSortOrder;
    }else if( termSortOrder!=sortOrder ){
      break;
      if( sortOrder==2 ){
        sortOrder = termSortOrder;
      }else if( termSortOrder!=sortOrder ){
        break;
      }
    }
    j++;
    pOBItem++;
    if( iColumn<0 ){
      seenRowid = 1;
      break;
    }else if( pTab->aCol[iColumn].notNull==0 ){
    }else if( pTab->aCol[iColumn].notNull==0 && isEq==0 ){
      uniqueNotNull = 0;
    }
  }

  /* If we have not found at least one ORDER BY term that matches the
  ** index, then show no progress. */
  if( pOBItem==&pOrderBy->a[nPriorSat] ) return nPriorSat;
︙