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https://issues.apache.org/jira/browse/HDFS-14655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16924650#comment-16924650
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Erik Krogen commented on HDFS-14655:
------------------------------------
v2 looks good to me except that I don't think {{newFixedThreadPool}} is the
right approach. This will create 5 threads per JN even if only 1 is ever used
since it sets the core pool size equal to the maximum pool size:
{code:title=HadoopExecutors}
public static ExecutorService newFixedThreadPool(int nThreads,
ThreadFactory threadFactory) {
return new HadoopThreadPoolExecutor(nThreads, nThreads,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>(),
threadFactory);
}
{code}
Instead, what we want is:
{code}
new HadoopThreadPoolExecutor(1, numThreads, 1L, TimeUnit.MINUTES, new
LinkedBlockingQueue<Runnable>(), threadFactory);
{code}
This gives a core pool size of 1 thread, so there will always be 1 running for
use. More can be spawned as-needed, but only up to {{numThreads}} at maximum.
> [SBN Read] Namenode crashes if one of The JN is down
> ----------------------------------------------------
>
> Key: HDFS-14655
> URL: https://issues.apache.org/jira/browse/HDFS-14655
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 3.3.0
> Reporter: Harshakiran Reddy
> Assignee: Ayush Saxena
> Priority: Critical
> Attachments: HDFS-14655-01.patch, HDFS-14655-02.patch,
> HDFS-14655.poc.patch
>
>
> {noformat}
> 2019-07-04 17:35:54,064 | INFO | Logger channel (from parallel executor) to
> XXXXXXX/XXXXXXX | Retrying connect to server: XXXXXXX/XXXXXXX. Already tried
> 9 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10,
> sleepTime=1000 MILLISECONDS) | Client.java:975
> 2019-07-04 17:35:54,087 | FATAL | Edit log tailer | Unknown error encountered
> while tailing edits. Shutting down standby NN. | EditLogTailer.java:474
> java.lang.OutOfMemoryError: unable to create new native thread
> at java.lang.Thread.start0(Native Method)
> at java.lang.Thread.start(Thread.java:717)
> at
> java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:957)
> at
> java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1378)
> at
> com.google.common.util.concurrent.MoreExecutors$ListeningDecorator.execute(MoreExecutors.java:440)
> at
> com.google.common.util.concurrent.AbstractListeningExecutorService.submit(AbstractListeningExecutorService.java:56)
> at
> org.apache.hadoop.hdfs.qjournal.client.IPCLoggerChannel.getJournaledEdits(IPCLoggerChannel.java:565)
> at
> org.apache.hadoop.hdfs.qjournal.client.AsyncLoggerSet.getJournaledEdits(AsyncLoggerSet.java:272)
> at
> org.apache.hadoop.hdfs.qjournal.client.QuorumJournalManager.selectRpcInputStreams(QuorumJournalManager.java:533)
> at
> org.apache.hadoop.hdfs.qjournal.client.QuorumJournalManager.selectInputStreams(QuorumJournalManager.java:508)
> at
> org.apache.hadoop.hdfs.server.namenode.JournalSet.selectInputStreams(JournalSet.java:275)
> at
> org.apache.hadoop.hdfs.server.namenode.FSEditLog.selectInputStreams(FSEditLog.java:1681)
> at
> org.apache.hadoop.hdfs.server.namenode.FSEditLog.selectInputStreams(FSEditLog.java:1714)
> at
> org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer.doTailEdits(EditLogTailer.java:307)
> at
> org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.doWork(EditLogTailer.java:460)
> at
> org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.access$300(EditLogTailer.java:410)
> at
> org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread$1.run(EditLogTailer.java:427)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:360)
> at
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1709)
> at
> org.apache.hadoop.security.SecurityUtil.doAsLoginUserOrFatal(SecurityUtil.java:483)
> at
> org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.run(EditLogTailer.java:423)
> 2019-07-04 17:35:54,112 | INFO | Edit log tailer | Exiting with status 1:
> java.lang.OutOfMemoryError: unable to create new native thread |
> ExitUtil.java:210
> {noformat}
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