hive-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sergey Shelukhin (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-10215) Large IN() clauses: deep hashCode performance during optimizer pass
Date Tue, 07 Apr 2015 19:46:12 GMT

    [ https://issues.apache.org/jira/browse/HIVE-10215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14483906#comment-14483906
] 

Sergey Shelukhin commented on HIVE-10215:
-----------------------------------------

I bet many more places could benefit from this... +1 for this one

> Large IN() clauses: deep hashCode performance during optimizer pass
> -------------------------------------------------------------------
>
>                 Key: HIVE-10215
>                 URL: https://issues.apache.org/jira/browse/HIVE-10215
>             Project: Hive
>          Issue Type: Bug
>          Components: Logical Optimizer
>    Affects Versions: 1.2.0
>            Reporter: Gopal V
>            Assignee: Gopal V
>            Priority: Minor
>         Attachments: HIVE-10215.1.patch
>
>
> The logical optimizer uses several maps and sets, which are exceeding expensive for large
IN() clauses due to the fact that several part of the queries walk over the lists without
short-circuiting during hashCode(), while equals() is faster due to short-circuiting via less
expensive operators.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message