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https://issues.apache.org/jira/browse/HBASE-14205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14907088#comment-14907088
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Hudson commented on HBASE-14205:
--------------------------------
FAILURE: Integrated in HBase-TRUNK #6836 (See
[https://builds.apache.org/job/HBase-TRUNK/6836/])
HBASE-14205 RegionCoprocessorHost System.nanoTime() performance bottleneck
(apurtell: rev 20ed465d07ba02c66d8f1af5746ee59dd446cb95)
*
hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/RegionListTmpl.jamon
*
hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionSourceImpl.java
*
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/MetricsRegionWrapperStub.java
*
hbase-hadoop2-compat/src/test/java/org/apache/hadoop/hbase/regionserver/TestMetricsRegionSourceImpl.java
*
hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionWrapper.java
*
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java
*
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionWrapperImpl.java
> RegionCoprocessorHost System.nanoTime() performance bottleneck
> --------------------------------------------------------------
>
> Key: HBASE-14205
> URL: https://issues.apache.org/jira/browse/HBASE-14205
> Project: HBase
> Issue Type: Bug
> Reporter: Jan Van Besien
> Assignee: Andrew Purtell
> Priority: Critical
> Fix For: 2.0.0, 1.2.0, 1.3.0
>
> Attachments: HBASE-14205.patch
>
>
> The tracking of execution time of coprocessor methods introduced in
> HBASE-11516 introduces 2 calls to System.nanoTime() per coprocessor method
> per coprocessor. This is resulting in a serious performance bottleneck in
> certain scenarios.
> For example consider the scenario where many rows are being ingested (PUT) in
> a table which has multiple coprocessors (we have up to 20 coprocessors). This
> results in 8 extra calls to System.nanoTime() per coprocessor (prePut,
> postPut, postStartRegionOperation and postCloseRegionOperation) which has in
> total (i.e. times 20) been seen to result in a 50% increase of execution time.
> I think it is generally considered bad practice to measure execution times on
> such a small scale (per single operation). Also note that measurements are
> taken even for coprocessors that do not even have an actual implementation
> for certain operations, making the problem worse.
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