[jira] [Created] (CALCITE-2790) AggregateJoinTransposeRule incorrectly pushes down distinct count into join

["Andrew Tsvelodub (JIRA)" <ji...@apache.org>]

Andrew Tsvelodub created CALCITE-2790:
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             Summary: AggregateJoinTransposeRule incorrectly pushes down distinct count into join
                 Key: CALCITE-2790
                 URL: https://issues.apache.org/jira/browse/CALCITE-2790
             Project: Calcite
          Issue Type: Bug
          Components: core
    Affects Versions: 1.18.0
            Reporter: Andrew Tsvelodub
            Assignee: Julian Hyde


AggregateJoinTransposeRule.EXTENDED can push down aggregate functions into the join.

For Distinct Count (and other distinct aggregate functions) this should not be performed the same way as for simple count, since distinct count is not a decomposable function. [1]

While this can be done in theory, by adding the distinct column to the list of groups in below aggregate[2], I want to fix the buggy behavior first, before trying to improve the existing rule.

[1] Dynamic Programming: The Next Step, M. Eich, G. Moerkotte ([https://ub-madoc.bib.uni-mannheim.de/37228/1/main.pdf)]
[2] Including Group-By in Query Optimization, S. Chaudhuri, K. Shim ([https://pdfs.semanticscholar.org/3079/5447cec18753254edbbd7839f0afa58b2a39.pdf)]



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