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https://issues.apache.org/jira/browse/HBASE-21657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16733858#comment-16733858
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stack commented on HBASE-21657:
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Oh, just to say I had similar travails over in HBASE-20188 [TESTING]
Performance trying to get the CPU to have a better profile random reading.
Didn't get to Scans. In HBASE-20188, messing w/ inlining, caching calculations,
and earlier selection on whether extendedcell or not paid dividends. The
StoreScanner#next here is nasty. Could you get a flame graph from your current
prod to see what its flamegraph looks like -- where branch-1 is spending its
time Scanning? Thanks [~openinx].
> PrivateCellUtil#estimatedSerializedSizeOf has been the bottleneck in 100%
> scan case.
> ------------------------------------------------------------------------------------
>
> Key: HBASE-21657
> URL: https://issues.apache.org/jira/browse/HBASE-21657
> Project: HBase
> Issue Type: Bug
> Components: Performance
> Reporter: Zheng Hu
> Assignee: Zheng Hu
> Priority: Major
> Fix For: 3.0.0, 2.2.0, 2.1.3, 2.0.5
>
> Attachments: HBASE-21657.v1.patch, HBASE-21657.v2.patch,
> HBase2.0.4-with-patch.v2.png, HBase2.0.4-without-patch-v2.png,
> hbase2.0.4-ssd-scan-traces.2.svg, hbase2.0.4-ssd-scan-traces.svg,
> hbase20-ssd-100-scan-traces.svg
>
>
> We are evaluating the performance of branch-2, and find that the throughput
> of scan in SSD cluster is almost the same as HDD cluster. so I made a
> FlameGraph on RS, and found that the
> PrivateCellUtil#estimatedSerializedSizeOf cost about 29% cpu, Obviously, it
> has been the bottleneck in 100% scan case.
> See the [^hbase20-ssd-100-scan-traces.svg]
> BTW, in our XiaoMi branch, we introduce a
> HRegion#updateReadRequestsByCapacityUnitPerSecond to sum up the size of cells
> (for metric monitor), so it seems the performance loss was amplified.
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