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Date: Fri, 20 Mar 2015 20:39:38 +0000 (UTC)
From: "stack (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
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Subject: [jira] [Commented] (HBASE-13291) Lift the scan ceiling
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    [ https://issues.apache.org/jira/browse/HBASE-13291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14372055#comment-14372055 ] 

stack commented on HBASE-13291:
-------------------------------

[~ram_krish] Thanks for keeping an eye on me. Will try your suggestion in a while.

Meantime, am able to get ScannerV2.next and all below inlined (see attached flame graph and patch breaking stuff into smaller methods) but the improvement is small. Could spend more time going down this path but payback is not of the proportions that I'm after... so passing on this for time being.  Will put up graph of benefit in a while.

> Lift the scan ceiling
> ---------------------
>
>                 Key: HBASE-13291
>                 URL: https://issues.apache.org/jira/browse/HBASE-13291
>             Project: HBase
>          Issue Type: Improvement
>          Components: Scanners
>    Affects Versions: 1.0.0
>            Reporter: stack
>            Assignee: stack
>         Attachments: traces.filterall.svg, traces.nofilter.svg, traces.smaller.svg
>
>
> Scanning medium sized rows with multiple concurrent scanners exhibits interesting 'ceiling' properties. A server runs at about 6.7k ops a second using 450% of possible 1600% of CPUs  when 4 clients each with 10 threads doing scan 1000 rows.  If I add '--filterAll' argument (do not return results), then we run at 1450% of possible 1600% possible but we do 8k ops a second.
> Let me attach flame graphs for two cases. Unfortunately, there is some frustrating dark art going on. Let me try figure it... Filing issue in meantime to keep score in.


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