[jira] [Comment Edited] (PHOENIX-4618) Optimize out order-by on sort-merge-join when possible

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

    [ https://issues.apache.org/jira/browse/PHOENIX-4618?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16795089#comment-16795089 ] 

chenglei edited comment on PHOENIX-4618 at 3/18/19 3:05 PM:
------------------------------------------------------------

This JIRA is contained by PHOENIX-5148.


was (Author: comnetwork):
This JIRA was contained by PHOENIX-5148.

> Optimize out order-by on sort-merge-join when possible
> ------------------------------------------------------
>
>                 Key: PHOENIX-4618
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-4618
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: Maryann Xue
>            Assignee: Maryann Xue
>            Priority: Major
>             Fix For: 4.15.0
>
>
> To do this, \{{OrderPreservingTracker}} relies solely on primary keys for inferring alignment between order-by expressions and the input sortedness. To implement this improvement, we need to have extra information of sortedness which supports equivalent sorted expressions. For example,
> {code}SELECT * FROM T1 JOIN T2 ON T1.a = T2.a and T1.b = T2.b{code}
> The result of the sort-merge-join is sorted on (T1.a, T1.b) and (T2.a, T2.b) at the same time.
> Thus, both 1)
> {code}SELECT * FROM T1 JOIN T2 ON T1.a = T2.a and T1.b = T2.b ORDER BY T1.a, T1.b{code}
> and 2)
> {code}SELECT * FROM T1 JOIN T2 ON T1.a = T2.a and T1.b = T2.b ORDER BY T2.a, T2.b{code}
> should avoid doing an extra order-by after the sort-merge-join operation.



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