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Overview
Comment:Disable the query flattener optimization for SELECT statements that are on the RHS of vector IN operators. This is a hack that fixes the bug described in ticket [da7841375186386c]. A better solution that does not disable the query flattener is needed, but this will server for the time being.
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SHA1: 27438fb43db4eae90fa005e7872debbb1db22c88
User & Date: drh 2016-11-23 21:01:38
Context
2016-11-23
21:08
Prevent a possible use-after-free bug in the query optimizer. check-in: 661b4506 user: drh tags: branch-3.15
21:01
Disable the query flattener optimization for SELECT statements that are on the RHS of vector IN operators. This is a hack that fixes the bug described in ticket [da7841375186386c]. A better solution that does not disable the query flattener is needed, but this will server for the time being. check-in: 27438fb4 user: drh tags: branch-3.15
20:44
Fix a potential use-after-free error during parsing of malformed CREATE TABLE statement. check-in: 0f956597 user: drh tags: branch-3.15
2016-11-17
13:13
Disable the query flattener optimization for SELECT statements that are on the RHS of vector IN operators. This is a hack that fixes the bug described in ticket [da7841375186386c]. A better solution that does not disable the query flattener is needed, but this will server for the time being. check-in: 005d5b87 user: drh tags: trunk
Changes
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Changes to src/wherecode.c.

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    }

    if( (pX->flags & EP_xIsSelect)==0 || pX->x.pSelect->pEList->nExpr==1 ){
      eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0);
    }else{
      Select *pSelect = pX->x.pSelect;
      sqlite3 *db = pParse->db;

      ExprList *pOrigRhs = pSelect->pEList;
      ExprList *pOrigLhs = pX->pLeft->x.pList;
      ExprList *pRhs = 0;         /* New Select.pEList for RHS */
      ExprList *pLhs = 0;         /* New pX->pLeft vector */

      for(i=iEq;i<pLoop->nLTerm; i++){
        if( pLoop->aLTerm[i]->pExpr==pX ){
................................................................................
          pX->pLeft = pLhs->a[0].pExpr;
        }else{
          pLeft->x.pList = pLhs;
          aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int) * nEq);
          testcase( aiMap==0 );
        }
        pSelect->pEList = pRhs;

        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap);

        testcase( aiMap!=0 && aiMap[0]!=0 );
        pSelect->pEList = pOrigRhs;
        pLeft->x.pList = pOrigLhs;
        pX->pLeft = pLeft;
      }
      sqlite3ExprListDelete(pParse->db, pLhs);
      sqlite3ExprListDelete(pParse->db, pRhs);







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    }

    if( (pX->flags & EP_xIsSelect)==0 || pX->x.pSelect->pEList->nExpr==1 ){
      eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0);
    }else{
      Select *pSelect = pX->x.pSelect;
      sqlite3 *db = pParse->db;
      u16 savedDbOptFlags = db->dbOptFlags;
      ExprList *pOrigRhs = pSelect->pEList;
      ExprList *pOrigLhs = pX->pLeft->x.pList;
      ExprList *pRhs = 0;         /* New Select.pEList for RHS */
      ExprList *pLhs = 0;         /* New pX->pLeft vector */

      for(i=iEq;i<pLoop->nLTerm; i++){
        if( pLoop->aLTerm[i]->pExpr==pX ){
................................................................................
          pX->pLeft = pLhs->a[0].pExpr;
        }else{
          pLeft->x.pList = pLhs;
          aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int) * nEq);
          testcase( aiMap==0 );
        }
        pSelect->pEList = pRhs;
        db->dbOptFlags |= SQLITE_QueryFlattener;
        eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap);
        db->dbOptFlags = savedDbOptFlags;
        testcase( aiMap!=0 && aiMap[0]!=0 );
        pSelect->pEList = pOrigRhs;
        pLeft->x.pList = pOrigLhs;
        pX->pLeft = pLeft;
      }
      sqlite3ExprListDelete(pParse->db, pLhs);
      sqlite3ExprListDelete(pParse->db, pRhs);

Changes to test/rowvalue3.test.

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    do_execsql_test 4.$tn.$tn2 "
      SELECT c FROM hh WHERE (a, b) in (SELECT x, y FROM k1) ORDER BY $orderby
    " $res
  }
}

#-------------------------------------------------------------------------
















finish_test







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    do_execsql_test 4.$tn.$tn2 "
      SELECT c FROM hh WHERE (a, b) in (SELECT x, y FROM k1) ORDER BY $orderby
    " $res
  }
}

#-------------------------------------------------------------------------

# 2016-11-17.  Query flattening in a vector SELECT on the RHS of an IN
# operator.  Ticket https://www.sqlite.org/src/info/da7841375186386c
#
do_execsql_test 5.0 {
  DROP TABLE IF EXISTS t1;
  DROP TABLE IF EXISTS t2;
  CREATE TABLE T1(a TEXT);
  INSERT INTO T1(a) VALUES ('aaa');
  CREATE TABLE T2(a TEXT PRIMARY KEY,n INT);
  INSERT INTO T2(a, n) VALUES('aaa',0);
  SELECT * FROM T2
  WHERE (a,n) IN (SELECT T1.a, V.n FROM T1, (SELECT * FROM (SELECT 0 n)) V);
} {aaa 0}


finish_test