hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Namit Jain (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-3639) join order across mutiple joins
Date Tue, 30 Oct 2012 07:12:24 GMT
Namit Jain created HIVE-3639:
--------------------------------

             Summary: join order across mutiple joins
                 Key: HIVE-3639
                 URL: https://issues.apache.org/jira/browse/HIVE-3639
             Project: Hive
          Issue Type: Improvement
          Components: Query Processor
            Reporter: Namit Jain


This came up during a discussion with Sambavi - please add any details I may
have missed.

For a query of the form:

select ..
from
A join B on A.c1 = B.c1
join C on B.c2=C.c2;


A,B are joined first and the result is then joined with C.
This is clearly sub-optimal if A is the largest table, in which case
B and C should be joined first, and then the result should be joined with A.


--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message