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Posted to issues@hbase.apache.org by "stack (JIRA)" <ji...@apache.org> on 2016/01/25 20:52:40 UTC
[jira] [Commented] (HBASE-13291) Lift the scan ceiling
[ https://issues.apache.org/jira/browse/HBASE-13291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15115855#comment-15115855 ]
stack commented on HBASE-13291:
-------------------------------
Here is another oldie but a goodie
> 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: 13291.hacks.txt, 13291.inlining.txt, Screen Shot 2015-03-26 at 12.12.13 PM.png, Screen Shot 2015-03-26 at 3.39.33 PM.png, TimeRange.patch, hack_to_bypass_bb.txt, nonBBposAndInineMvccVint.txt, q (1).png, scan_no_mvcc_optimized.svg, traces.7.svg, traces.filterall.svg, traces.nofilter.svg, traces.small2.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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