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Posted to dev@phoenix.apache.org by "James Taylor (JIRA)" <ji...@apache.org> on 2015/04/11 01:23:13 UTC

[jira] [Commented] (PHOENIX-1837) Detect ordered/unordered group-by

    [ https://issues.apache.org/jira/browse/PHOENIX-1837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14490529#comment-14490529 ] 

James Taylor commented on PHOENIX-1837:
---------------------------------------

FWIW, once PHOENIX-1826 is implemented, the TrackOrderPreservingExpressionCompiler could be used on the ORDER BY expression, but it's probably better to be able to determine this early as you're suggesting. Note also, somewhat related, but we can remove the need to sort GROUP BY rows at all which would help performance quite a bit: PHOENIX-1006.

> Detect ordered/unordered group-by
> ---------------------------------
>
>                 Key: PHOENIX-1837
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-1837
>             Project: Phoenix
>          Issue Type: Sub-task
>            Reporter: Maryann Xue
>            Assignee: Maryann Xue
>   Original Estimate: 120h
>  Remaining Estimate: 120h
>
> With ordered group-by, we would do much less work. The existing Phoenix code depends on TrackOrderPreservingExpressionCompiler to calculate the flag. But given that we would no longer use any of the Phoenix parse tree nodes and the TrackOrderPreservingExpressionCompiler is a parse tree node visitor, we should now implement the same logic with Calcite RexNode.



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