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https://issues.apache.org/jira/browse/CASSANDRA-11940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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T Jake Luciani updated CASSANDRA-11940:
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Comment: was deleted
(was: I think this is actually the same issue as CASSANDRA-8729
Recycling the Mapped byte buffer is causing read before write.)
> Look into better default file_cache_size for 2.2
> ------------------------------------------------
>
> Key: CASSANDRA-11940
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11940
> Project: Cassandra
> Issue Type: Improvement
> Reporter: T Jake Luciani
> Assignee: T Jake Luciani
> Fix For: 2.2.x
>
> Attachments: abnormal disk read throughput.png
>
>
> CASSANDRA-8464 added support for mmapped decompression where in version <=
> 2.1 the reads were all decompressed in standard heap buffers.
> Since the usage of the file_cache is based solely on the buffer capacity we
> should/can make this much larger in 2.2 when the disk access mode is mmap.
> The downside of this cache being too small is made worse by 8464 since the
> buffers are mmapped/unmapped causing explicit page faults.
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