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Date: Sun, 19 Sep 2010 13:45:33 -0400 (EDT)
From: "Stu Hood (JIRA)" <jira@apache.org>
To: commits@cassandra.apache.org
Subject: [jira] Commented: (CASSANDRA-1434) ColumnFamilyOutputFormat
 performs blocking writes for large batches
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    [ https://issues.apache.org/jira/browse/CASSANDRA-1434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12912263#action_12912263 ] 

Stu Hood commented on CASSANDRA-1434:
-------------------------------------

* ArrayBlockingQueue.isEmpty will kill client threads if their queue is ever empty
* Interrupt handling doesn't seem like a clearer solution for killing client threads: what happens when an interrupt in received during a mutation?
* I don't like the idea of indefinite retries: pretending that the cluster is never unavailable sidesteps Hadoop's own retry system
* As mentioned in IRC, batchSize == 1 does not seem like a good value to hardcode. Any amount of overhead becomes measurable when you are sending small enough values: mutations containing a single integer might increase in size X fold for instance

> ColumnFamilyOutputFormat performs blocking writes for large batches
> -------------------------------------------------------------------
>
>                 Key: CASSANDRA-1434
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1434
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Hadoop
>            Reporter: Stu Hood
>            Assignee: Stu Hood
>             Fix For: 0.7 beta 2
>
>         Attachments: 0001-Switch-away-from-Multimap-and-fix-regression-introdu.patch, 0002-Improve-concurrency-and-add-basic-retries-by-attempt.patch, 0003-Switch-RingCache-back-to-multimap.patch, 0004-Replace-Executor-with-map-of-threads.patch, 1434-v3.txt
>
>
> By default, ColumnFamilyOutputFormat batches {{mapreduce.output.columnfamilyoutputformat.batch.threshold}} or {{Long.MAX_VALUE}} mutations, and then performs a blocking write.

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