SQLite

Check-in [7455d932f5]
Login

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

Overview
Comment:Allow LIKE operators that appear in a WHERE clause to be included in the cursor-hint for a cursor on the rhs of a LEFT JOIN.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | cursor-hints
Files: files | file ages | folders
SHA1: 7455d932f5079ffe40462a8c119fc22b8a9bcbcc
User & Date: dan 2016-06-20 17:22:06.973
Context
2016-06-20
17:25
For a table on the rhs of a LEFT JOIN operator, do not include terms like "IS NULL" from the WHERE clause in the cursor-hint. These may be false for rows that the cursor would otherwise visit, but true for a row of all NULL values generated by the LEFT JOIN. (check-in: 913e595615 user: dan tags: trunk)
17:22
Allow LIKE operators that appear in a WHERE clause to be included in the cursor-hint for a cursor on the rhs of a LEFT JOIN. (Closed-Leaf check-in: 7455d932f5 user: dan tags: cursor-hints)
2016-06-17
19:27
Include WHERE terms in the cursor-hint passed to a cursor opened for the rhs of a LEFT JOIN iff we can be sure that those terms will not evaluate to true if the LEFT JOIN generates a row of NULLs. (check-in: 998095aba0 user: dan tags: cursor-hints)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/wherecode.c.
638
639
640
641
642
643
644
645
646
647
648
649





650


651
652
653
654
655
656
657
**
**   col IS NULL
**   col IS NOT NULL
**   coalesce(col, 1)
**   CASE WHEN col THEN 0 ELSE 1 END
*/
static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_IS || pExpr->op==TK_FUNCTION 
   || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT 
   || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE 
  ){
    pWalker->eCode = 1;





  }


  return WRC_Continue;
}


/*
** This function is called on every node of an expression tree used as an
** argument to the OP_CursorHint instruction. If the node is a TK_COLUMN







|




>
>
>
>
>
|
>
>







638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
**
**   col IS NULL
**   col IS NOT NULL
**   coalesce(col, 1)
**   CASE WHEN col THEN 0 ELSE 1 END
*/
static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_IS 
   || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT 
   || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE 
  ){
    pWalker->eCode = 1;
  }else if( pExpr->op==TK_FUNCTION ){
    int d1;
    char d2[3];
    if( 0==sqlite3IsLikeFunction(pWalker->pParse->db, pExpr, &d1, d2) ){
      pWalker->eCode = 1;
    }
  }

  return WRC_Continue;
}


/*
** This function is called on every node of an expression tree used as an
** argument to the OP_CursorHint instruction. If the node is a TK_COLUMN
Changes to test/cursorhint2.test.
159
160
161
162
163
164
165












166
167
168
}

do_extract_hints_test 2.10 {
  SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE x2.b = 32+32
} {
  x2 {AND(EQ(c1,ADD(32,32)),EQ(c0,r[2]))}
}













finish_test








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



159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
}

do_extract_hints_test 2.10 {
  SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE x2.b = 32+32
} {
  x2 {AND(EQ(c1,ADD(32,32)),EQ(c0,r[2]))}
}

do_extract_hints_test 2.11 {
  SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE x2.b LIKE 'abc%'
} {
  x2 {AND(expr,EQ(c0,r[2]))}
}

do_extract_hints_test 2.11 {
  SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE coalesce(x2.b, 1)
} {
  x2 {EQ(c0,r[2])}
}

finish_test