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Posted to commits@cassandra.apache.org by "Jonathan Ellis (JIRA)" <ji...@apache.org> on 2014/05/12 17:39:18 UTC

[jira] [Updated] (CASSANDRA-5863) In process (uncompressed) page cache

     [ https://issues.apache.org/jira/browse/CASSANDRA-5863?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis updated CASSANDRA-5863:
--------------------------------------

    Fix Version/s:     (was: 2.1 rc1)
                   3.0

> In process (uncompressed) page cache
> ------------------------------------
>
>                 Key: CASSANDRA-5863
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5863
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: T Jake Luciani
>              Labels: performance
>             Fix For: 3.0
>
>
> 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. Initially this could be a off heap cache but it would be great to put these decompressed chunks onto a SSD so the hot data lives on a fast disk similar to https://github.com/facebook/flashcache.



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