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https://issues.apache.org/jira/browse/HBASE-21738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16747712#comment-16747712
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Zheng Hu commented on HBASE-21738:
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bq. BTW compared to 1.x based write flow, we have now some synchronized blocks
for the size accounting in Segment level or so. Would be better to eliminate
that also
I've seen that, it's ThreadSafeMemStoreSizing. Maybe use a LongAdder instead
of AtomicXXX ?
> Remove all the CSLM#size operation in our memstore because it's an quite time
> consuming.
> ----------------------------------------------------------------------------------------
>
> Key: HBASE-21738
> URL: https://issues.apache.org/jira/browse/HBASE-21738
> Project: HBase
> Issue Type: Sub-task
> Components: Performance
> Reporter: Zheng Hu
> Assignee: Zheng Hu
> Priority: Critical
> Fix For: 3.0.0, 2.2.0, 2.1.3, 2.0.5
>
> Attachments: HBASE-21738.v1.patch, HBASE-21738.v2.patch,
> HBASE-21738.v3.patch, HBASE-21738.v4.patch, add-some-log.patch,
> image-2019-01-18-14-03-28-662.png, log.txt, performance-after-the-patch.v3.png
>
>
> Made some performance test for 100% put case in branch-2 before.
> We can see that there are many latency peak in p999 latency curve , and the
> peak time are almost the point time which our region is flushing.
> See the [hbase20-ssd-put-10000000000-rows-latencys-and-qps
> |https://issues.apache.org/jira/secure/attachment/12955341/12955341_image-2019-01-18-14-03-28-662.png]
> And, I used the
> [add-some-log.patch|https://issues.apache.org/jira/secure/attachment/12955342/add-some-log.patch]
> to log some time consuming when we grab the update.writeLock() to make a
> memstore snapshot. Tested again, I found those logs in [log.txt.
> |https://issues.apache.org/jira/secure/attachment/12955343/log.txt]
> Seems most of the time was consumed when taking memstore snapshot.. Let me
> dig into this.
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