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https://issues.apache.org/jira/browse/HDFS-17067?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Xing Lin updated HDFS-17067:
----------------------------
Description:
In HDFS-17030, we introduced an ExecutorService, to submit getHAServiceState()
requests. We constructed the ExecutorService directly from a basic
ThreadPoolExecutor, without setting _allowCoreThreadTimeOut_ to true. Then, the
core thread will be kept up and running even when the main thread exits. To fix
it, one could set _allowCoreThreadTimeOut_ to true. However, in this PR, we
decide to directly use an existing executorService implementation
(_BlockingThreadPoolExecutorService_) in hadoop instead. It takes care of
setting _allowCoreThreadTimeOut_ and also allows setting the thread prefix.
{code:java}
private final ExecutorService nnProbingThreadPool =
new ThreadPoolExecutor(1, 4, 1L, TimeUnit.MINUTES,
new ArrayBlockingQueue<Runnable>(1024));
{code}
A second minor issue is we did not shutdown the executorService in close(). It
is a minor issue as close() will only be called when the garbage collector
starts to reclaim an ObserverReadProxyProvider object, not when there is no
reference to the ObserverReadProxyProvider object. The time between when an
ObserverReadProxyProvider becomes dereferenced and when the garage collector
actually starts to reclaim that object is out of control/under-defined (unless
the program is shutdown with an explicit System.exit(1)).
was:
In HDFS-17030, we introduced an ExecutorService, to submit getHAServiceState()
requests. We constructed the ExecutorService directly from a basic
ThreadPoolExecutor, without setting _allowCoreThreadTimeOut_ to true. Then, the
core thread will be kept up and running even when the main thread exits. To fix
it, one could set _allowCoreThreadTimeOut_ to true. However, in this PR, we
decide to directly use an existing executorService implementation
(_BlockingThreadPoolExecutorService_) in hadoop instead. It takes care of
setting _allowCoreThreadTimeOut_ and also allows setting the thread prefix.
Second minor issue is we did not shutdown the executorService in close(). It is
a minor issue as close() will only be called when the garbage collector starts
to reclaim an ObserverReadProxyProvider object, not when there is no reference
to the ObserverReadProxyProvider object. The time between when an
ObserverReadProxyProvider becomes dereferenced and when the garage collector
actually starts to reclaim that object is out of control/under-defined (unless
the program is shutdown with an explicit System.exit(1)).
{code:java}
private final ExecutorService nnProbingThreadPool =
new ThreadPoolExecutor(1, 4, 1L, TimeUnit.MINUTES,
new ArrayBlockingQueue<Runnable>(1024));
{code}
> Use BlockingThreadPoolExecutorService for nnProbingThreadPool in
> ObserverReadProxy
> ----------------------------------------------------------------------------------
>
> Key: HDFS-17067
> URL: https://issues.apache.org/jira/browse/HDFS-17067
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs
> Affects Versions: 3.4.0
> Reporter: Xing Lin
> Assignee: Xing Lin
> Priority: Major
>
> In HDFS-17030, we introduced an ExecutorService, to submit
> getHAServiceState() requests. We constructed the ExecutorService directly
> from a basic ThreadPoolExecutor, without setting _allowCoreThreadTimeOut_ to
> true. Then, the core thread will be kept up and running even when the main
> thread exits. To fix it, one could set _allowCoreThreadTimeOut_ to true.
> However, in this PR, we decide to directly use an existing executorService
> implementation (_BlockingThreadPoolExecutorService_) in hadoop instead. It
> takes care of setting _allowCoreThreadTimeOut_ and also allows setting the
> thread prefix.
> {code:java}
> private final ExecutorService nnProbingThreadPool =
> new ThreadPoolExecutor(1, 4, 1L, TimeUnit.MINUTES,
> new ArrayBlockingQueue<Runnable>(1024));
> {code}
> A second minor issue is we did not shutdown the executorService in close().
> It is a minor issue as close() will only be called when the garbage collector
> starts to reclaim an ObserverReadProxyProvider object, not when there is no
> reference to the ObserverReadProxyProvider object. The time between when an
> ObserverReadProxyProvider becomes dereferenced and when the garage collector
> actually starts to reclaim that object is out of control/under-defined
> (unless the program is shutdown with an explicit System.exit(1)).
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