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https://issues.apache.org/jira/browse/HBASE-4367?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13103345#comment-13103345
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stack commented on HBASE-4367:
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bq. Yet I think it's nice to print out dates in human-readable forms in some
places. I don't know about you, but I can't tell you what time 12349582034 is
For sure, but it looked like a silly compare of timestamps was all that was
going on in the patch (perhaps there a toString in here somewhere...).
> Deadlock in MemStore flusher due to JDK internally synchronizing on current
> thread
> ----------------------------------------------------------------------------------
>
> Key: HBASE-4367
> URL: https://issues.apache.org/jira/browse/HBASE-4367
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.90.4
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Priority: Critical
> Fix For: 0.92.0
>
> Attachments: 4367.txt, hbase-4367.txt
>
>
> We observed a deadlock in production between the following threads:
> - IPC handler thread holding the monitor lock on MemStoreFlusher inside
> reclaimMemStoreMemory, waiting to obtain MemStoreFlusher.lock (the reentrant
> lock member)
> - cacheFlusher thread inside flushRegion holds MemStoreFlusher.lock, and then
> calls PriorityCompactionQueue.add, which calls
> PriorityCompactionQueue.addToRegionsInQueue, which calls
> CompactionRequest.toString(), which calls Date.toString. If this occurs just
> after a GC under memory pressure, Date.toString needs to reload locale
> information (stored in a soft reference), so it calls
> ResourceBundle.loadBundle, which uses Thread.currentThread() as a
> synchronizer (see sun bug http://bugs.sun.com/view_bug.do?bug_id=6915621).
> Since the current thread is the MemStoreFlusher itself, we have a lock order
> inversion and a deadlock.
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