[
https://issues.apache.org/jira/browse/CASSANDRA-4937?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13494553#comment-13494553
]
Pavel Yaskevich commented on CASSANDRA-4937:
--------------------------------------------
If you are talking about CRAR object cache then it lasts until SSTableReader
has no more references and SSTable itself is cleaned and prepared to be
deleted, every caller upon using close method on CRAR would return instance to
the queue to be reused by other threads (readers, compaction, streaming etc.).
> CRAR improvements (object cache + CompressionMetadata chunk offset storage
> moved off-heap).
> -------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-4937
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4937
> Project: Cassandra
> Issue Type: Improvement
> Affects Versions: 1.1.6
> Reporter: Pavel Yaskevich
> Assignee: Pavel Yaskevich
> Priority: Minor
> Fix For: 1.1.7
>
> Attachments: CASSANDRA-4937.patch
>
>
> After good amount of testing on one of the clusters it was found that in
> order to improve read latency we need to minimize allocation rate that
> compression involves, that minimizes GC (as well as heap usage) and
> substantially decreases latency on read heavy workloads.
> I have also discovered that RAR skip cache harms performance in situation
> when reads are done in parallel with compaction working with relatively big
> SSTable files (few GB and more). The attached patch removes possibility to
> skip cache from compressed files (I can also add changes to RAR to remove
> skip cache functionality as a separate patch).
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
