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https://issues.apache.org/jira/browse/HBASE-13097?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14335950#comment-14335950
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zhangduo commented on HBASE-13097:
----------------------------------
I modified TestAcidGuarantees to use only one Connection
instance(HBaseTestingUtility.getConnection). It works.
This is jmap result
{noformat}
1: 11022336 264536064
io.netty.buffer.PoolThreadCache$MemoryRegionCache$Entry
2: 24960 44488704
[Lio.netty.buffer.PoolThreadCache$MemoryRegionCache$Entry;
{noformat}
I only use one Connection instance, so If we have multiple Connection instance
it is easy to cause OOM or long running Full GCs.
I do not know if we really need to use multiple Connections in some tests. If
so, I think we need a netty expert to help us preventing OOM when using
multiple Bootstraps(or maybe we should not use multiple Bootstraps?)
> Netty PooledByteBufAllocator cause OOM in some unit test
> --------------------------------------------------------
>
> Key: HBASE-13097
> URL: https://issues.apache.org/jira/browse/HBASE-13097
> Project: HBase
> Issue Type: Bug
> Components: IPC/RPC, test
> Affects Versions: 2.0.0, 1.1.0
> Reporter: zhangduo
>
> In some unit tests(such as TestAcidGuarantees) we create multiple Connection
> instance. If we use AsyncRpcClient, then there will be multiple netty
> Bootstrap and every Bootstrap has its own PooledByteBufAllocator.
> I haven't read the code clearly but it uses some threadlocal technics and
> jmap shows io.netty.buffer.PoolThreadCache$MemoryRegionCache$Entry is the
> biggest things on Heap.
> See
> https://builds.apache.org/job/HBase-TRUNK/6168/artifact/hbase-server/target/surefire-reports/org.apache.hadoop.hbase.TestAcidGuarantees-output.txt
> {noformat}
> 2015-02-24 23:50:29,704 WARN [JvmPauseMonitor]
> util.JvmPauseMonitor$Monitor(167): Detected pause in JVM or host machine (eg
> GC): pause of approximately 20133ms
> GC pool 'PS MarkSweep' had collection(s): count=15 time=55525ms
> {noformat}
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