[jira] [Resolved] (LUCENE-7570) Tragic events during merges can lead to deadlock

2017-02-08 Thread Michael McCandless (JIRA) 

 [ 
https://issues.apache.org/jira/browse/LUCENE-7570?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Michael McCandless resolved LUCENE-7570.

   Resolution: Fixed
Fix Version/s: 5.5.4

> Tragic events during merges can lead to deadlock
> 
>
> Key: LUCENE-7570
> URL: https://issues.apache.org/jira/browse/LUCENE-7570
> Project: Lucene - Core
>  Issue Type: Bug
>  Components: core/index
>Affects Versions: 5.5, master (7.0)
>Reporter: Joey Echeverria
>Assignee: Michael McCandless
> Fix For: master (7.0), 5.5.4, 6.4
>
> Attachments: LUCENE-7570.patch, thread_dump.txt
>
>
> When an {{IndexWriter#commit()}} is stalled due to too many pending merges, 
> you can get a deadlock if the currently active merge thread hits a tragic 
> event.
> # The thread performing the commit synchronizes on the the {{commitLock}} in 
> {{commitInternal}}.
> # The thread goes on to to call {{ConcurrentMergeScheduler#doStall()}} which 
> {{waits()}} on the {{ConcurrentMergeScheduler}} object. This release the 
> merge scheduler's monitor lock, but not the {{commitLock}} in {{IndexWriter}}.
> # Sometime after this wait begins, the merge thread gets a tragic exception 
> can calls {{IndexWriter#tragicEvent()}} which in turn calls 
> {{IndexWriter#rollbackInternal()}}.
> # The {{IndexWriter#rollbackInternal()}} synchronizes on the {{commitLock}} 
> which is still held by the committing thread from (1) above which is waiting 
> on the merge(s) to complete. Hence, deadlock.
> We hit this bug with Lucene 5.5, but I looked at the code in the master 
> branch and it looks like the deadlock still exists there as well.



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[jira] [Resolved] (LUCENE-7570) Tragic events during merges can lead to deadlock

2016-12-09 Thread Michael McCandless (JIRA) 

 [ 
https://issues.apache.org/jira/browse/LUCENE-7570?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Michael McCandless resolved LUCENE-7570.

   Resolution: Fixed
Fix Version/s: 6.4
   master (7.0)

> Tragic events during merges can lead to deadlock
> 
>
> Key: LUCENE-7570
> URL: https://issues.apache.org/jira/browse/LUCENE-7570
> Project: Lucene - Core
>  Issue Type: Bug
>  Components: core/index
>Affects Versions: 5.5, master (7.0)
>Reporter: Joey Echeverria
> Fix For: master (7.0), 6.4
>
> Attachments: LUCENE-7570.patch, thread_dump.txt
>
>
> When an {{IndexWriter#commit()}} is stalled due to too many pending merges, 
> you can get a deadlock if the currently active merge thread hits a tragic 
> event.
> # The thread performing the commit synchronizes on the the {{commitLock}} in 
> {{commitInternal}}.
> # The thread goes on to to call {{ConcurrentMergeScheduler#doStall()}} which 
> {{waits()}} on the {{ConcurrentMergeScheduler}} object. This release the 
> merge scheduler's monitor lock, but not the {{commitLock}} in {{IndexWriter}}.
> # Sometime after this wait begins, the merge thread gets a tragic exception 
> can calls {{IndexWriter#tragicEvent()}} which in turn calls 
> {{IndexWriter#rollbackInternal()}}.
> # The {{IndexWriter#rollbackInternal()}} synchronizes on the {{commitLock}} 
> which is still held by the committing thread from (1) above which is waiting 
> on the merge(s) to complete. Hence, deadlock.
> We hit this bug with Lucene 5.5, but I looked at the code in the master 
> branch and it looks like the deadlock still exists there as well.



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