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Posted to commits@cassandra.apache.org by "Jonathan Ellis (Reopened) (JIRA)" <ji...@apache.org> on 2012/02/23 19:22:49 UTC
[jira] [Reopened] (CASSANDRA-3610) Checksum improvement for
CompressedRandomAccessReader
[ https://issues.apache.org/jira/browse/CASSANDRA-3610?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jonathan Ellis reopened CASSANDRA-3610:
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We still do a lot of int and long CRC updates in the commitlog though. Seems like that would be a better fit for the pure java implementation, which still does better for <= 64 bytes.
> Checksum improvement for CompressedRandomAccessReader
> -----------------------------------------------------
>
> Key: CASSANDRA-3610
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3610
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 1.1.0
> Environment: JVM
> Reporter: Vijay
> Assignee: Vijay
> Priority: Minor
> Fix For: 1.1.1
>
> Attachments: 0001-use-pure-java-CRC32-v2.patch, 0001-use-pure-java-CRC32-v3.patch, 0001-use-pure-java-CRC32.patch, TestCrc32Performance.java, TestCrc32Performance.java, crc32Test.xlsx
>
>
> When compression is on, Currently we see checksum taking up about 40% of the CPU more than snappy library.
> Looks like hadoop solved it by implementing their own checksum, we can either use it or implement something like that.
> http://images.slidesharecdn.com/1toddlipconyanpeichen-cloudera-hadoopandperformance-final-111110132228-phpapp01-slide-15-768.jpg?1321043717
> in our test env it provided 50% improvement over native implementation which uses jni to call the OS.
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