hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Siying Dong (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HIVE-1783) CommonJoinOperator optimize the case of 1:1 join
Date Thu, 18 Nov 2010 00:17:16 GMT

     [ https://issues.apache.org/jira/browse/HIVE-1783?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Siying Dong updated HIVE-1783:
------------------------------

    Status: Patch Available  (was: Open)

> CommonJoinOperator optimize the case of 1:1 join
> ------------------------------------------------
>
>                 Key: HIVE-1783
>                 URL: https://issues.apache.org/jira/browse/HIVE-1783
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Siying Dong
>            Assignee: Siying Dong
>            Priority: Minor
>         Attachments: HIVE-1783.1.patch, HIVE-1783.2.patch, HIVE-1783.3.patch, HIVE-1783.4.patch
>
>
> CommonJoinOperator.genObject() is expensive. It does a recursive and keeps lots of states
because it has to:
> 1. handle null cases for outer joins
> 2. handle the case of duplicated keys from one join party
> We can do a minor optimization to detect a 1:1 join (which is quite common) before calling
CommonJoinOperator.genObject() and forward columns in a simple for-loop if we are sure neither
of 1 or 2 will happen.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message