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https://issues.apache.org/jira/browse/CASSANDRA-5863?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15206596#comment-15206596
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Branimir Lambov commented on CASSANDRA-5863:
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bq. Can you re-run the stress with 500 threads vs 50 to see what it looks like
under some load?
The run is
[here|http://cstar.datastax.com/tests/id/2324a078-f040-11e5-8634-0256e416528f].
This time the 8G run is only as fast as the 480M one; this may be because this
many threads need more memory and we reserve 8G but only use 0.85 (this can be
found in the nodetool info output). Room for improvement there.
> In process (uncompressed) page cache
> ------------------------------------
>
> Key: CASSANDRA-5863
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5863
> Project: Cassandra
> Issue Type: Sub-task
> Reporter: T Jake Luciani
> Assignee: Branimir Lambov
> Labels: performance
> Fix For: 3.x
>
>
> Currently, for every read, the CRAR reads each compressed chunk into a
> byte[], sends it to ICompressor, gets back another byte[] and verifies a
> checksum.
> This process is where the majority of time is spent in a read request.
> Before compression, we would have zero-copy of data and could respond
> directly from the page-cache.
> It would be useful to have some kind of Chunk cache that could speed up this
> process for hot data, possibly off heap.
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