[CALCITE-2104] Add separate rules for "AggregateUnionAggregateRule" to reduce potential matching cost in VolcanoPlanner

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.13.0
• Fix Version/s: 1.16.0
• Component/s: core
• Assignee: Julian Hyde
• Reporter: lincoln lee
• Created: 21/Dec/17 12:55
• Updated: 27/Feb/24 22:23
• Resolved: 27/Dec/17 00:39

Description

Problem: when optimize some sql (has Union + Aggregate pattern) based on VolcanoPlanner may take a long time(tens of seconds or a few minutes).
After adding the time cost statistics for each rule during the optimization phase, I found that "AggregateUnionAggregateRule" has a large value, but the query pattern will not be matched finally.
So I try to make a minor change for AggregateUnionAggregateRule and the statistics shows a improvement for the same query be tested. (see the attached image)

1. Current AggregateUnionAggregateRule's match pattern:

         topAgg
            |    
          Union
        /        \
     Rel        Rel

2. Real patterns that can possibly be matched:

         topAgg
            |    
          Union
        /     \
bottomAgg      Rel

Or

         topAgg
            |    
          Union
        /        \
    Rel      bottomAgg

Will this change reasonable? (BTW, would it be useful to add some time cost statistics to VolcanoPlanner like the attached image below? I saw a CalciteTimingTracer class and getSqlTimingTracer() in CalciteTracer but not used.)

Issue Links

• relates to: CALCITE-260 RelOptPlannerRule should be able to match one child and ignore another