Ruben Quesada Lopez created CALCITE-3198:
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Summary: ReduceExpressionsRule.FILTER_INSTANCE does not reduce
'NOT(x=a AND x=b)'
Key: CALCITE-3198
URL: https://issues.apache.org/jira/browse/CALCITE-3198
Project: Calcite
Issue Type: Bug
Affects Versions: 1.20.0
Reporter: Ruben Quesada Lopez
Currently, ReduceExpressionsRule.FILTER_INSTANCE can successfully reduce a
query like this one (see RelOptRulesTest#testReduceConstantsDup):
{code}
// query:
select d.deptno from dept d where d.deptno=7 and d.deptno=8
// plan before:
LogicalProject(DEPTNO=[$0])
LogicalFilter(condition=[AND(=($0, 7), =($0, 8))])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
// plan after:
LogicalProject(DEPTNO=[$0])
LogicalValues(tuples=[[]])
{code}
As we can see, since the filter is 'always false', the
LogicalTableScan+LogicalFilter are correctly replaced by an empty LogicalValues.
However, the same filter with a NOT expression, is not correctly simplified:
{code}
// query:
select d.deptno from dept d where not(d.deptno=7 and d.deptno=8)
// plan before:
LogicalProject(DEPTNO=[$0])
LogicalFilter(condition=[NOT(AND(=($0, 7), =($0, 8)))])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
// plan after (actual):
LogicalProject(DEPTNO=[$0])
LogicalFilter(condition=[OR(<>($0, 7), <>($0, 8))])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
// plan after (expected):
LogicalProject(DEPTNO=[$0])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
{code}
Since the filter is the negated of an 'always false filter' (the one used in
the previous query), it is therefore an 'always true filter', so the expected
behavior is that the LogicalFilter should be removed, and it is not.
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