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Posted to issues@hbase.apache.org by "Zhihong Yu (JIRA)" <ji...@apache.org> on 2012/04/29 05:40:45 UTC
[jira] [Commented] (HBASE-5898) Consider double-checked locking for
block cache lock
[ https://issues.apache.org/jira/browse/HBASE-5898?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13264456#comment-13264456 ]
Zhihong Yu commented on HBASE-5898:
-----------------------------------
Interesting idea.
Minor comments:
The indentation for while (true) loop is off.
Changes to conf/hbase-site.xml belong to another JIRA.
> Consider double-checked locking for block cache lock
> ----------------------------------------------------
>
> Key: HBASE-5898
> URL: https://issues.apache.org/jira/browse/HBASE-5898
> Project: HBase
> Issue Type: Improvement
> Components: performance
> Affects Versions: 0.94.1
> Reporter: Todd Lipcon
> Attachments: hbase-5898.txt
>
>
> Running a workload with a high query rate against a dataset that fits in cache, I saw a lot of CPU being used in IdLock.getLockEntry, being called by HFileReaderV2.readBlock. Even though it was all cache hits, it was wasting a lot of CPU doing lock management here. I wrote a quick patch to switch to a double-checked locking and it improved throughput substantially for this workload.
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