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From Piotr Kołaczkowski (JIRA) <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-8576) Primary Key Pushdown For Hadoop
Date Fri, 29 May 2015 08:59:18 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-8576?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14564440#comment-14564440
] 

Piotr Kołaczkowski commented on CASSANDRA-8576:
-----------------------------------------------

Yes, it would be good to test it in a mixed version cluster. If cassandra.jar is part of the
Hadoop job classpath, then there shouldn't be any problems. Problems might happen if cassandra.jar
is on the classpath of Hadoop TT (inherited by all jobs), and different TTs used mixed versions
of it (with / without this patch).

> Primary Key Pushdown For Hadoop
> -------------------------------
>
>                 Key: CASSANDRA-8576
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8576
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Hadoop
>            Reporter: Russell Alexander Spitzer
>            Assignee: Alex Liu
>             Fix For: 2.1.x
>
>         Attachments: 8576-2.1-branch.txt, 8576-trunk.txt, CASSANDRA-8576-v2-2.1-branch.txt,
CASSANDRA-8576-v3-2.1-branch.txt
>
>
> I've heard reports from several users that they would like to have predicate pushdown
functionality for hadoop (Hive in particular) based services. 
> Example usecase
> Table with wide partitions, one per customer
> Application team has HQL they would like to run on a single customer
> Currently time to complete scales with number of customers since Input Format can't pushdown
primary key predicate
> Current implementation requires a full table scan (since it can't recognize that a single
partition was specified)



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