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Zoltan Haindrich commented on CALCITE-2726: ------------------------------------------- It's a great idea to deprecate ExprSimplifier - as it may only cause trouble...after getting to the bottom of it; it was just a couple of minutes fixing it. > ReduceExpressionRule may oversimplify filter conditions containing nulls > ------------------------------------------------------------------------ > > Key: CALCITE-2726 > URL: https://issues.apache.org/jira/browse/CALCITE-2726 > Project: Calcite > Issue Type: Bug > Reporter: Zoltan Haindrich > Assignee: Zoltan Haindrich > Priority: Major > Fix For: 1.18.0 > > > ReduceExpressionsRule is invoking > [simplifications|https://github.com/apache/calcite/blob/efec74deb80da1708fd42bcc2b57289840869346/core/src/main/java/org/apache/calcite/rel/rules/ReduceExpressionsRule.java#L549] > - by using > [ExprSimplifier|https://github.com/apache/calcite/blob/efec74deb80da1708fd42bcc2b57289840869346/core/src/main/java/org/apache/calcite/rex/RexUtil.java#L2611] > which unfortunately doesn't switch unknownAs mode (because it's a visitor). > Can be reproduced by adding the following test case to RelOptRulesTests > {code} > @Test public void testIncorrectlyRemovedCondition() { > HepProgram program = new HepProgramBuilder() > .addRuleInstance(ReduceExpressionsRule.FILTER_INSTANCE) > .build(); > String sql = > // "select * from emp where ( (empno=1 and mgr=1) or > (empno=null and mgr=1) ) is null"; > "select * from emp where ( (empno=null and mgr=1) ) is null"; > checkPlanning(program, sql); > } > {code} > Plan should retain the condition; right now it incorrectly simplified to > false. > {code} > <TestCase name="testIncorrectlyRemovedCondition"> > <Resource name="sql"> > <![CDATA[select * from emp where ( (empno=null and mgr=1) ) is > null]]> > </Resource> > <Resource name="planBefore"> > <![CDATA[ > LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], > SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8]) > LogicalFilter(condition=[IS NULL(AND(=($0, null), =($3, 1)))]) > LogicalTableScan(table=[[CATALOG, SALES, EMP]]) > ]]> > </Resource> > <Resource name="planAfter"> > <![CDATA[ > LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], > SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8]) > LogicalValues(tuples=[[]]) > ]]> > </Resource> > </TestCase> > {code} -- This message was sent by Atlassian JIRA (v7.6.3#76005)