[CALCITE-1465] Store constants as a derived field in RelOptPredicateList

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.11.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 23/Oct/16 21:38
• Updated: 06/Jan/17 19:30
• Resolved: 24/Oct/16 22:36

Description

I propose that we compute predicate constants when we create a RelOptPredicateList, and store them in an immutable field constantMap.

Currently, any rule that wishes to detect constants by aliasing (e.g. if we know x = 5 and x = y then we can deduce y = 5) must start with a RelOptPredicateList (from the metadata supplier) and call the ReduceExpressionsRule.predicateConstants method. This method is called many times: in the current Calcite suite 1,201 instances of RelOptPredicateList are created and predicateConstants is called 82,670 times.

Pre-computing would use a little extra memory but reduce the method calls by ~68x.