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https://issues.apache.org/jira/browse/CASSANDRA-6764?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13911207#comment-13911207
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John Carrino commented on CASSANDRA-6764:
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Good point. Ok. We may just run this with 2000 writer threads and call it a
day.
I would still like to add the throw if the mutation is being dropped. For
periodic this throw will just be eaten by the FutureTask but for batch it
will fail the write.
> Using Batch commitlog_sync is slow and doesn't actually batch writes
> --------------------------------------------------------------------
>
> Key: CASSANDRA-6764
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6764
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: John Carrino
> Fix For: 1.2.16
>
> Attachments: cassandra_6764_v2.patch
>
>
> The assumption behind batch commit mode is that the client does it's own
> batching and wants to wait until the write is durable before returning. The
> problem is that the queue that cassandra uses under the covers only allows
> for a single ROW (RowMutation) per thread (concurrent_writes). This means
> that commitlog_sync_batch_window_in_ms should really be called sleep_between
> each_concurrent_writes_rows_in_ms.
> I assume the reason this slipped by for so long is that no one uses batch
> mode, probably because people say "it's slow". We need durability so this
> isn't an option.
> However it doesn't need to be this slow.
> Also, if you write a row that is larger than the commit log size it silently
> (warn) fails to put it in the commit log. This is not ideal for batch mode.
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