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Posted to issues@hive.apache.org by "Nemon Lou (Jira)" <ji...@apache.org> on 2021/09/14 01:38:00 UTC
[jira] [Commented] (HIVE-3562) Some limit can be pushed down to map
stage
[ https://issues.apache.org/jira/browse/HIVE-3562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17414659#comment-17414659 ]
Nemon Lou commented on HIVE-3562:
---------------------------------
[~girishsk] I reported a same issue , also with some analysis : HIVE-24579
> Some limit can be pushed down to map stage
> ------------------------------------------
>
> Key: HIVE-3562
> URL: https://issues.apache.org/jira/browse/HIVE-3562
> Project: Hive
> Issue Type: Bug
> Reporter: Navis Ryu
> Assignee: Navis Ryu
> Priority: Trivial
> Fix For: 0.12.0
>
> Attachments: HIVE-3562.D5967.1.patch, HIVE-3562.D5967.2.patch, HIVE-3562.D5967.3.patch, HIVE-3562.D5967.4.patch, HIVE-3562.D5967.5.patch, HIVE-3562.D5967.6.patch, HIVE-3562.D5967.7.patch, HIVE-3562.D5967.8.patch, HIVE-3562.D5967.9.patch
>
>
> Queries with limit clause (with reasonable number), for example
> {noformat}
> select * from src order by key limit 10;
> {noformat}
> makes operator tree,
> TS-SEL-RS-EXT-LIMIT-FS
> But LIMIT can be partially calculated in RS, reducing size of shuffling.
> TS-SEL-RS(TOP-N)-EXT-LIMIT-FS
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