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From "Christopher Tubbs (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-1732) Resolve table name to table id once in Accumulo input format
Date Thu, 26 Sep 2013 17:09:03 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-1732?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13778978#comment-13778978
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Christopher Tubbs commented on ACCUMULO-1732:
---------------------------------------------

The same issue applies to renames in general for any arbitrary application that scans tables.
If we make the M/R API robust against this, should we also make it available for other applications?
Or is the M/R API a special case (because it's implementation details that it creates a separate
scanner per mapper).

Also, maybe that's the behavior you want? Maybe you're trying to rename a table and replace
it with a backup clone, to limit the impact of some problematic or corrupt data?
                
> Resolve table name to table id once in Accumulo input format
> ------------------------------------------------------------
>
>                 Key: ACCUMULO-1732
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-1732
>             Project: Accumulo
>          Issue Type: Bug
>    Affects Versions: 1.4.0
>            Reporter: Keith Turner
>            Assignee: Corey J. Nolet
>            Priority: Minor
>
> AccumuloInputFormat (and I suspect AccumuloOutputFormat) sends the table name to each
mapper.  The mapper uses this table name to create a scanner.  In the case of the following
events a map reduce job could read from two different table ids.   
>  # start M/R job reading table A
>  # rename table A (tableId=1) to table C
>  # rename table B (tableId=2) to table A
> If the input format passed table id 1 to the mappers, then the renames would not cause
a problem.

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