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  1. Calcite
  2. CALCITE-4029

ProjectRemoveRule auto pruning may prevent rules from running if mixed conventions are used in a logical plan

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Minor
    • Resolution: Not A Problem
    • Affects Version/s: 1.23.0
    • Fix Version/s: None
    • Component/s: core
    • Labels:
      None

      Description

      Preconditions to reproduce the issue:

      1. Logical plan has mixed conventions (for example, a bottom node is a TableScan in a final convention while other nodes are regular logical nodes with NONE convention).
      2. There is a rule that expects a logical node with an input (like a rule matching "operand(LogicalSort.class, operand(RelNode.class, any()))")
      3. A project over the scan is trivial (like SELECT * FROM ...)

      The issue is related to https://issues.apache.org/jira/browse/CALCITE-3939, please see comments for a detailed debugging of a real-life reproducing case.

      Example:

      Logical plan with a leaf nodes in a custom convention:

      LogicalSort[NONE]
       LogicalProject[NONE]
        CustomScan[CUSTOM_CONVENTION]

      A rule configured (RuleX) matches "operand(LogicalSort.class, operand(RelNode.class, any()))".

      Without ProjectRemoveRule auto pruning

      ProjectRemoveRule recognizes LogicalProject as trivial an merges it into a single RelSet with CustomScan. 

      RuleX can run on top of this change as far as LogicalProject has a logical node (LogicalProject in RelSubset[NONE]) as an input.

       

      With ProjectRemoveRule auto pruning

      ProjectRemoveRule recognizes LogicalProject as trivial but removes it with it's RelSet so the CustomScan is the only node in it's RelSet, RelSubset[CUSTOM_CONVENTION].

      RuleX can't run on top of this change as far as LogicalProject has an empty input RelSubset[NONE] of the RelSet with the CustomScan.

      Possible workarounds

      1. Disable ProjectRemoveRule auto pruning.
      2. Use only logical nodes in a logical plan, for the example above: use LogicalScan - >  CustomScanRule - > CustomScan instead of direct use of CustomScan.

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              • Assignee:
                Unassigned
                Reporter:
                anha Anton Haidai
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                Dates

                • Created:
                  Updated:
                  Resolved: