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From "Gopal V (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (TEZ-2606) Cache-friendly data structure for sorting
Date Wed, 15 Jul 2015 01:00:06 GMT

    [ https://issues.apache.org/jira/browse/TEZ-2606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14627363#comment-14627363
] 

Gopal V commented on TEZ-2606:
------------------------------

[~ozawa]: Sure, MR types can also have their own prefix comparators - but it turned out to
be a circular dependency problem when I tried (i.e MRv2 Text cannot depend on a Tez interface).

https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/exec/tez/DagUtils.java#L391

is how Hive injects these and I'm not sure how you want to plug in the comparators.

> Cache-friendly data structure for sorting
> -----------------------------------------
>
>                 Key: TEZ-2606
>                 URL: https://issues.apache.org/jira/browse/TEZ-2606
>             Project: Apache Tez
>          Issue Type: Sub-task
>            Reporter: Tsuyoshi Ozawa
>            Assignee: Tsuyoshi Ozawa
>
> Alphasort[1]  mentions prefix key sort is effective way. I'd like to suggest to change
a layout of ring buffer to include prefix of key in meta data. This can improve the cache
hit rate when sorting.
> [1] Alphasort: http://dl.acm.org/citation.cfm?id=615237



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