Constant reduction at Rex level

[Vladimir Sitnikov]

Hi,

Does anyone know why optiq does not perform constant reduction at rex level?

I noticed if (false) code in OptiqPrepareImpl:

    // Change the below to enable constant-reduction.

    if (false) {

      planner.addRule(ReduceExpressionsRule.PROJECT_INSTANCE);

      planner.addRule(ReduceExpressionsRule.FILTER_INSTANCE);

      planner.addRule(ReduceExpressionsRule.CALC_INSTANCE);

      planner.addRule(ReduceExpressionsRule.JOIN_INSTANCE);

      planner.addRule(ReduceValuesRule.FILTER_INSTANCE);

      planner.addRule(ReduceValuesRule.PROJECT_FILTER_INSTANCE);

      planner.addRule(ReduceValuesRule.PROJECT_INSTANCE);

    }

It looks like those rules might help optimizing where 1=2 to empty relation eliminating the enumerator(), next(), etc.

From my non-optiq experience, those kind of conditions often arise from "generic queries".

Vladimir