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https://issues.apache.org/jira/browse/HBASE-16890?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15610797#comment-15610797
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ramkrishna.s.vasudevan commented on HBASE-16890:
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Just posting as per Stack request to what was done.
bq.There is also a means of carrying unsync'd appends from one WAL to another
if a WAL goes unresponsive, a feature we'd like to keep (Another 'feature' of
asyncwal that we don't have in FSHLog is some size accounting so if N bytes of
appends, sync regardless....we should keep this too, something current FSHLog
can't do because it intentionally lets appends and sync run independent of each
other).
Ok. Agree.
bq. Any sense of how many syncs you were aggregating in your tests?
Am not sure how to account for this in particular. The JFR reports says most of
the time is spent in checksum as part of the sync call in case AsyncWAL but
other than that I am not sure specifically how to see that. But I got your
intention out here.
And one reason what I see there is a speed up in my case is that because of the
hack I intentionally come out of wait for some of the syncs than it was doing
previously. But that should not be major the factor for the gain here.
> Analyze the performance of AsyncWAL and fix the same
> ----------------------------------------------------
>
> Key: HBASE-16890
> URL: https://issues.apache.org/jira/browse/HBASE-16890
> Project: HBase
> Issue Type: Sub-task
> Components: wal
> Affects Versions: 2.0.0
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Fix For: 2.0.0
>
> Attachments: AsyncWAL_disruptor.patch, Screen Shot 2016-10-25 at
> 7.34.47 PM.png, Screen Shot 2016-10-25 at 7.39.07 PM.png, Screen Shot
> 2016-10-25 at 7.39.48 PM.png, async.svg, classic.svg, contention.png,
> contention_defaultWAL.png
>
>
> Tests reveal that AsyncWAL under load in single node cluster performs slower
> than the Default WAL. This task is to analyze and see if we could fix it.
> See some discussions in the tail of JIRA HBASE-15536.
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