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Posted to commits@cassandra.apache.org by "Oleksandr Petrov (JIRA)" <ji...@apache.org> on 2013/06/29 22:55:20 UTC

[jira] [Commented] (CASSANDRA-5504) Eternal iteration when using older hadoop version due to next() call and empty key value

    [ https://issues.apache.org/jira/browse/CASSANDRA-5504?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13696196#comment-13696196 ] 

Oleksandr Petrov commented on CASSANDRA-5504:
---------------------------------------------

Can anyone confirm if 1.2.4 contains the fix, too?
It seems to work, it's just not clear wether fix made it there or it's just a coincidence...
                
> Eternal iteration when using older hadoop version due to next() call and empty key value
> ----------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-5504
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5504
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Hadoop
>    Affects Versions: 1.2.0
>            Reporter: Oleksandr Petrov
>            Assignee: Oleksandr Petrov
>            Priority: Minor
>             Fix For: 1.2.5
>
>         Attachments: 5504-v3.txt, patch2.diff, patch.diff
>
>
> Currently, when using newer hadoop versions, due to the call to 
> next(ByteBuffer key, SortedMap<ByteBuffer, IColumn> value)
> within ColumnFamilyRecordReader, because `key.clear();` is called, key is emptied. That causes the StaticRowIterator and WideRowIterator to glitch, namely, when Iterables.getLast(rows).key is called, key is already empty. This will cause Hadoop to request the same range again and again all the time.
> Please see the attached patch/diff, it simply adds lastRowKey (ByteBuffer) and saves it for the next iteration along with all the rows, this allows query for the next range to be fully correct.
> This patch is branched from 1.2.3 version.
> Tested against Cassandra 1.2.3, with Hadoop 1.0.3, 1.0.4 and 0.20.2

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