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Overview
Comment:This additional fix prevents a partial index from being qualified for use if the constraint that qualifies the partial index is part of the ON clause of a LEFT JOIN.
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SHA1: 1a1516e4da26dcee35e6fbb6604ce252faf3d116
User & Date: drh 2015-02-24 16:48:59.496
Context
2015-02-24
18:39
More test cases to help ensure that partial indexes do not get used if their qualifing constraint is inside the ON clause of a LEFT JOIN. (Closed-Leaf check-in: c6399958a1 user: drh tags: tkt-2326c258)
16:48
This additional fix prevents a partial index from being qualified for use if the constraint that qualifies the partial index is part of the ON clause of a LEFT JOIN. (check-in: 1a1516e4da user: drh tags: tkt-2326c258)
16:05
Make sure partial automatic indexes are not based on terms in the ON clause of a LEFT JOIN. Fix for ticket [2326c258d02ead3]. UPDATE: This fix does not work where the partial index is a named index. (check-in: c0f4e308a5 user: drh tags: tkt-2326c258)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/where.c.
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/* Check to see if a partial index with pPartIndexWhere can be used
** in the current query.  Return true if it can be and false if not.
*/
static int whereUsablePartialIndex(int iTab, WhereClause *pWC, Expr *pWhere){
  int i;
  WhereTerm *pTerm;
  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    if( sqlite3ExprImpliesExpr(pTerm->pExpr, pWhere, iTab) ) return 1;




  }
  return 0;
}

/*
** Add all WhereLoop objects for a single table of the join where the table
** is idenfied by pBuilder->pNew->iTab.  That table is guaranteed to be








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/* Check to see if a partial index with pPartIndexWhere can be used
** in the current query.  Return true if it can be and false if not.
*/
static int whereUsablePartialIndex(int iTab, WhereClause *pWC, Expr *pWhere){
  int i;
  WhereTerm *pTerm;
  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    if( sqlite3ExprImpliesExpr(pTerm->pExpr, pWhere, iTab)
     && !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
    ){
      return 1;
    }
  }
  return 0;
}

/*
** Add all WhereLoop objects for a single table of the join where the table
** is idenfied by pBuilder->pNew->iTab.  That table is guaranteed to be
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Changes to test/autoindex4.test.
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do_execsql_test autoindex4-3.0 {
  CREATE TABLE A(Name text);
  CREATE TABLE Items(ItemName text , Name text);
  INSERT INTO Items VALUES('Item1','Parent');
  INSERT INTO Items VALUES('Item2','Parent');
  CREATE TABLE B(Name text);
  










  SELECT Items.ItemName
    FROM Items
      LEFT JOIN A ON (A.Name = Items.ItemName and Items.ItemName = 'dummy')
      LEFT JOIN B ON (B.Name = Items.ItemName)
    WHERE Items.Name = 'Parent'
    ORDER BY Items.ItemName;
} {Item1 Item2}








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do_execsql_test autoindex4-3.0 {
  CREATE TABLE A(Name text);
  CREATE TABLE Items(ItemName text , Name text);
  INSERT INTO Items VALUES('Item1','Parent');
  INSERT INTO Items VALUES('Item2','Parent');
  CREATE TABLE B(Name text);
  
  SELECT Items.ItemName
    FROM Items
      LEFT JOIN A ON (A.Name = Items.ItemName and Items.ItemName = 'dummy')
      LEFT JOIN B ON (B.Name = Items.ItemName)
    WHERE Items.Name = 'Parent'
    ORDER BY Items.ItemName;
} {Item1 Item2}
do_execsql_test autoindex4-3.1 {
  CREATE INDEX Items_x1 ON Items(ItemName,Name) WHERE ItemName = 'dummy';
  
  SELECT Items.ItemName
    FROM Items
      LEFT JOIN A ON (A.Name = Items.ItemName and Items.ItemName = 'dummy')
      LEFT JOIN B ON (B.Name = Items.ItemName)
    WHERE Items.Name = 'Parent'
    ORDER BY Items.ItemName;
} {Item1 Item2}
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