[jira] [Comment Edited] (POOL-337) EvictionTimer does not remove cancelled tasks from the executor, leading to an IllegalStateException when the evictor attempts to evict

["Phil Steitz (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/POOL-337?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16433251#comment-16433251 ] 

Phil Steitz edited comment on POOL-337 at 4/11/18 4:03 PM:
-----------------------------------------------------------

Sorry, I missed the unit test in the updated PR.  In my testing I did not configure a listener to get the swallowed exceptions.  I think the analysis is correct and the patch should fix the issue.  It might be good to consider a little refactoring that would allow the GOP to hold a reference to the task that it needs to cancel (i.e. change the type of the Evictor) so you would not need to maintain the map in the EvictionTimer.


was (Author: psteitz):
Sorry, I missed the unit test in the updated PR.  What I am still not getting is how the stack trace at the top can happen.  I can see how the memory leak is a problem and I think there is definitely a bug here, but I would like to be able to reproduce this directly from the GOP API, which I can't do.  The underlying Evictor task should get cancelled while the eviction lock is held, but somehow the executor is still firing it in the trace at the top.

> EvictionTimer does not remove cancelled tasks from the executor, leading to an IllegalStateException when the evictor attempts to evict
> ---------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: POOL-337
>                 URL: https://issues.apache.org/jira/browse/POOL-337
>             Project: Commons Pool
>          Issue Type: Bug
>    Affects Versions: 2.5.0
>            Reporter: Reinald Verheij
>            Priority: Major
>         Attachments: EvictionTimer.java, EvictionTimer.java.original-from-2.5.0.java
>
>
> EvictionTimer does not remove cancelled tasks from the executor, leading to an IllegalStateException when the evictor attempts to evict.
>  
> EvictionTimer::schedule() adds eviction tasks to the executor, but the cancel does not remove it. This is asymmetric and leads to the following exception:
> {noformat}
> java.lang.IllegalStateException: Pool not open
> 	at org.apache.commons.pool2.impl.BaseGenericObjectPool.assertOpen(BaseGenericObjectPool.java:713)
> 	at org.apache.commons.pool2.impl.GenericObjectPool.evict(GenericObjectPool.java:721)
> 	at org.apache.commons.pool2.impl.BaseGenericObjectPool$Evictor.run(BaseGenericObjectPool.java:1077)
> 	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> 	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
> 	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
> 	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
> 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> 	at java.lang.Thread.run(Thread.java:748){noformat}
> I think the cancel would need to remember the future which returned from {{executor::scheduleWithFixedDelay()}} in {{schedule()}} and then do something like this (see  [^EvictionTimer.java] compared to original  [^EvictionTimer.java.original-from-2.5.0.java] )
> {code:java}
> if (futures.containsKey(task)) {
>     futures.remove(task).cancel(false);
>     executor.purge();
> }{code}



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