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Posted to commits@cassandra.apache.org by "Philip (flip) Kromer (JIRA)" <ji...@apache.org> on 2010/08/30 09:31:53 UTC
[jira] Commented: (CASSANDRA-1434) ColumnFamilyOutputFormat
performs blocking writes for large batches
[ https://issues.apache.org/jira/browse/CASSANDRA-1434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12904098#action_12904098 ]
Philip (flip) Kromer commented on CASSANDRA-1434:
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The blocking behavior is causing 'broken pipe' errors (even with relatively small batch sizes) when cassandra latency is high.
It also makes the whole cluster resonate: one slow node blocks many writers, which then all unblock at the same time, write bursts of enough size to cause a compaction or GC, etc simultaneously on every node. This means adding more writers doesn't work around the blocking write
> 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
> Fix For: 0.7.0
>
>
> By default, ColumnFamilyOutputFormat batches {{mapreduce.output.columnfamilyoutputformat.batch.threshold}} or {{Long.MAX_VALUE}} mutations, and then performs a blocking write.
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