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https://issues.apache.org/jira/browse/HADOOP-17728?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17362205#comment-17362205
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yikf edited comment on HADOOP-17728 at 6/12/21, 1:00 AM:
---------------------------------------------------------

[~liuml07] and [~Jim_Brennan] Thanks for discussion.

I'm thinking, the issue is remove() blocks indefinitely, so this would never 
let it check Thread.interrupted() again if nothing is in the queue. reference: 
[code|#L4009]]

FYI, It is better that have a timeout?


was (Author: kaifeiyi):
[~liuml07] and [~Jim_Brennan] Thanks for discussion.

I'm thinking, the issue is remove() blocks indefinitely, so this would never 
let it check Thread.interrupted() again if nothing is in the queue.

[code|#L4009]]

FYI, It is better that have a timeout?

> Fix issue of the StatisticsDataReferenceCleaner cleanUp
> -------------------------------------------------------
>
>                 Key: HADOOP-17728
>                 URL: https://issues.apache.org/jira/browse/HADOOP-17728
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: fs
>    Affects Versions: 3.2.1
>            Reporter: yikf
>            Assignee: yikf
>            Priority: Minor
>              Labels: pull-request-available, reverted
>          Time Spent: 5h 10m
>  Remaining Estimate: 0h
>
> Cleaner thread will be blocked if we remove reference from ReferenceQueue 
> unless the `queue.enqueue` called.
> ----
>     As shown below, We call ReferenceQueue.remove() now while cleanUp, Call 
> chain as follow:
>                          *StatisticsDataReferenceCleaner#queue.remove()  ->  
> ReferenceQueue.remove(0)  -> lock.wait(0)*
>     But, lock.notifyAll is called when queue.enqueue only, so Cleaner thread 
> will be blocked.
>  
> ThreadDump:
> {code:java}
> "Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007f7afc088800 
> nid=0x2119 in Object.wait() [0x00007f7b00230000]
>    java.lang.Thread.State: WAITING (on object monitor)
>         at java.lang.Object.wait(Native Method)
>         - waiting on <0x00000000c00c2f58> (a java.lang.ref.Reference$Lock)
>         at java.lang.Object.wait(Object.java:502)
>         at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
>         - locked <0x00000000c00c2f58> (a java.lang.ref.Reference$Lock)
>         at 
> java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153){code}



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