Vladimir Sitnikov created CALCITE-2452:
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Summary: RexSimplify: avoid multiple similar optimization passes
over the same nodes
Key: CALCITE-2452
URL: https://issues.apache.org/jira/browse/CALCITE-2452
Project: Calcite
Issue Type: Sub-task
Reporter: Vladimir Sitnikov
Assignee: Julian Hyde
simplifyAndTerms(List<RexNode> terms) has two loops and it calls simplify on
each expression twice.
simplifyAnd(RexCall e) calls simplifyList (that walks all the tree down), then
simplifyAnd2ForUnknownAsFalse calls simplify_ again.
It looks like just one pass should be sufficient for most of the cases, and the
logic should probably be adjusted as follows:
{code:java}
simplify(RexNode node){
// e.g. simplify the node with assumption that all the arguments were
simplified, etc, avoid complicated checks
node = simplifyTrivialCases(node);
// this walks over the tree, simplifies operands first then simplifies the
call itself
node = simplifyArgumentsThenSimplifyNode(node);
return node;
}
Method naming should clearly indicate that the method is heavy, so it would not
accidentally be used.
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