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https://issues.apache.org/jira/browse/PHOENIX-4618?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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chenglei resolved PHOENIX-4618.
-------------------------------
Resolution: Fixed
Fix Version/s: 4.15.0
> 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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