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https://issues.apache.org/jira/browse/DAEMON-333?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Manuel Dominguez Sarmiento updated DAEMON-333:
----------------------------------------------
    Description: 
The shutdown sequence invokes System.gc() several times. I'm not sure why this 
would be necessary, especially considering that System.gc() is only a hint and 
the JVM will not necessarily do anything when this method is invoked. 
Especially if -XX:+DisableExplicitGC is used, which is fairly common practice 
in production environments.

In our case, we use rather huge heaps (over 100 GB) so shutdown can take 
forever, depending on how much uncollected garbage there is in the JVM heap. 
We've always used -XX:+DisableExplicitGC so this was never apparent, however we 
decided to stop using -XX:+DisableExplicitGC after careful code review showed 
none of our apps or supporting libraries are using System.gc() and sometimes we 
want to trigger GC manually from monitoring tools (Jconsole, VisualVM, etc.) - 
but we found the hard way that Commons Daemon / jsvc is using System.gc() on 
shutdown, preventing the speedy shutdown we were used to.

Re-introducing XX:+DisableExplicitGC fixes the problem, and shutdown is back to 
normal, takes less than 8 seconds on our hardware.

  was:
The shutdown sequence invokes System.gc() several times. I'm not sure why this 
would be necessary, especially considering that System.gc() is only a hint and 
the JVM will not necessarily do anything when this method is invoked. 
Especially if -XX:+DisableExplicitGC is used, which is fairly common practice 
in production environments.

In our case, we use rather huge heaps (over 100 GB) so shutdown can take 
forever, depending on how much uncollected garbage there is in the JVM heap. 
We've always used -XX:+DisableExplicitGC so this was never apparent, however we 
decided to stop using -XX:+DisableExplicitGC after careful code review showed 
none of our apps or supporting libraries are using System.gc() and sometimes we 
want to trigger GC manually from monitoring tools (Jconsole, VisualVM, etc.) - 
but we found the hard way that Commons Daemon / jsvc is using System.gc() on 
shutdown, preventing the speedy shutdown we were used to.


> Stop abusing System.gc() on Commons Daemon jsvc shutdown
> --------------------------------------------------------
>
>                 Key: DAEMON-333
>                 URL: https://issues.apache.org/jira/browse/DAEMON-333
>             Project: Commons Daemon
>          Issue Type: Bug
>          Components: Jsvc
>    Affects Versions: 1.0.15
>            Reporter: Manuel Dominguez Sarmiento
>
> The shutdown sequence invokes System.gc() several times. I'm not sure why 
> this would be necessary, especially considering that System.gc() is only a 
> hint and the JVM will not necessarily do anything when this method is 
> invoked. Especially if -XX:+DisableExplicitGC is used, which is fairly common 
> practice in production environments.
> In our case, we use rather huge heaps (over 100 GB) so shutdown can take 
> forever, depending on how much uncollected garbage there is in the JVM heap. 
> We've always used -XX:+DisableExplicitGC so this was never apparent, however 
> we decided to stop using -XX:+DisableExplicitGC after careful code review 
> showed none of our apps or supporting libraries are using System.gc() and 
> sometimes we want to trigger GC manually from monitoring tools (Jconsole, 
> VisualVM, etc.) - but we found the hard way that Commons Daemon / jsvc is 
> using System.gc() on shutdown, preventing the speedy shutdown we were used to.
> Re-introducing XX:+DisableExplicitGC fixes the problem, and shutdown is back 
> to normal, takes less than 8 seconds on our hardware.



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