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Posted to commits@cassandra.apache.org by "Jordan West (Jira)" <ji...@apache.org> on 2019/09/17 20:59:00 UTC

[jira] [Comment Edited] (CASSANDRA-15295) Running into deadlock when do CommitLog initialization

    [ https://issues.apache.org/jira/browse/CASSANDRA-15295?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16931810#comment-16931810 ] 

Jordan West edited comment on CASSANDRA-15295 at 9/17/19 8:58 PM:
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Happy to [~gzh1992n]. A few comments:

 
 * I verified it does not affect 3.0 branch because CommitLogSegmentManager#start exits immediately after starting managerThread instead of calling advaceAllocatingFrom(null);
 * The database doesn’t start, which causes many tests to fail as well, because there is no default commit log segment manager factory set
 * CommitLogInitWithExpcetionTest#L63 - should check prior to this call that initThread is not null

Minor naming nits (do with them what you please):
 * Rename KillerHook => OnKillHook, and onKill => execute
 * Drop the “I*” naming for the CommitLogSegmentMgrFactoryInterface. Consider renaming it CommitLogSegmentManagerFactory


was (Author: jrwest):
Happy to [~gzh1992n]. A few comments:

 
 * I verified it does not affect 3.0 branch because CommitLogSegmentManager#start exits immediately after starting managerThread instead of calling advaceAllocatingFrom(null);
 * The database doesn’t start, which causes many tests to fail as well, because there is no default commit log segment manager factory set
 * CommitLogInitWithExpcetionTest#L63 - should check prior to this call that initThread is not null
 * Minor naming nits (do with them what you please):
 * Rename KillerHook => OnKillHook, and onKill => execute
 * Drop the “I*” naming for the CommitLogSegmentMgrFactoryInterface. Consider renaming it CommitLogSegmentManagerFactory

> Running into deadlock when do CommitLog initialization
> ------------------------------------------------------
>
>                 Key: CASSANDRA-15295
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-15295
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Local/Commit Log
>            Reporter: Zephyr Guo
>            Assignee: Zephyr Guo
>            Priority: Normal
>         Attachments: jstack.log, pstack.log, screenshot-1.png, screenshot-2.png, screenshot-3.png
>
>
> Recently, I found a cassandra(3.11.4) node stuck in STARTING status for a long time.
>  I used jstack to saw what happened. The main thread stuck in *AbstractCommitLogSegmentManager.awaitAvailableSegment*
>  !screenshot-1.png! 
> The strange thing is COMMIT-LOG-ALLOCATOR thread state was runnable but it was not actually running.  
>  !screenshot-2.png! 
> And then I used pstack to troubleshoot. I found COMMIT-LOG-ALLOCATOR block on java class initialization.
>   !screenshot-3.png! 
> This is a deadlock obviously. CommitLog waits for a CommitLogSegment when initializing. In this moment, the CommitLog class is not initialized and the main thread holds the class lock. After that, COMMIT-LOG-ALLOCATOR creates a CommitLogSegment with exception and call *CommitLog.handleCommitError*(static method).  COMMIT-LOG-ALLOCATOR will block on this line because CommitLog class is still initializing.
>  
>  



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