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[jira] [Created] (CALCITE-2658) Introducing more ReduceExpressionRules


Chunwei Lei created CALCITE-2658:
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             Summary: Introducing more ReduceExpressionRules
                 Key: CALCITE-2658
                 URL: https://issues.apache.org/jira/browse/CALCITE-2658
             Project: Calcite
          Issue Type: Bug
          Components: core
    Affects Versions: 1.17.0
            Reporter: Chunwei Lei
            Assignee: Julian Hyde
             Fix For: 1.18.0


It is useful to have rules reducing Exchange/Sort/SortExchange keys, e.g.,

SELECT key,value FROM (SELECT 1 AS key, value FROM src) r DISTRIBUTE BY key;

can be reduced to 

SELECT 1 AS key, value FROM src;    # Since singleton requirement may already required by SELECT.

SELECT key,value FROM (SELECT 1 AS key, value FROM src) r ORDER BY key;

can be reduced to

SELECT 1 AS key, value FROM src;    # Since ordering on constant is useless.



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