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Posted to commits@cassandra.apache.org by "Christian Rolf (JIRA)" <ji...@apache.org> on 2014/02/06 14:46:09 UTC

[jira] [Updated] (CASSANDRA-6665) Batching in CqlRecordWriter

     [ https://issues.apache.org/jira/browse/CASSANDRA-6665?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Christian Rolf updated CASSANDRA-6665:
--------------------------------------

    Attachment: batchWrite.txt

Never submitted a patch here before, let me know if the format's bad.

> Batching in CqlRecordWriter
> ---------------------------
>
>                 Key: CASSANDRA-6665
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6665
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Hadoop
>         Environment: Cluster of 12 nodes, each node with 256-384 vnodes. RPC threads capped at 2048.
>            Reporter: Christian Rolf
>            Priority: Minor
>         Attachments: batchWrite.txt
>
>
> We're writing from Pig map tasks, about 20 million records of one integer each. 
> For the case of 12 nodes, with 256-384 vnodes per node, we get around 4000 threads per mapper. This obviously overloads the nodes, since the number of RPC threads are capped, and the write fails. 
> Also, each transfer is only in the order of a few bytes of payload. Clearly batching is a good solution.



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