[jira] [Commented] (CASSANDRA-2527) Add ability to snapshot data as input to hadoop jobs

["Jonathan Ellis (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-2527?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13839472#comment-13839472 ] 

Jonathan Ellis commented on CASSANDRA-2527:
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bq. Not really feasible; Hadoop is a special case since we can seq scan sstables without having to fully "open" them (sample indexes, populate key cache, etc)

... so, I'm not sure how interesting that leaves this given that we're trying to do predicate pushdown for Hadoop queries that could be indexed, for instance.

> Add ability to snapshot data as input to hadoop jobs
> ----------------------------------------------------
>
>                 Key: CASSANDRA-2527
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2527
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Jeremy Hanna
>            Assignee: Tyler Hobbs
>            Priority: Minor
>              Labels: hadoop
>             Fix For: 2.1
>
>
> It is desirable to have immutable inputs to hadoop jobs for the duration of the job.  That way re-execution of individual tasks do not alter the output.  One way to accomplish this would be to snapshot the data that is used as input to a job.



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