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https://issues.apache.org/jira/browse/HBASE-28271?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17798694#comment-17798694
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Viraj Jasani commented on HBASE-28271:
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Snapshot is the only consumer of the lock procedure that provides countdown
latch to the procedure and waits until the latch is accessed by the procedure,
no other consumers of lock procedure provides non-null latch to implement any
wait strategy.
So, yes the plan is to make it generic enough but the only consumers we have is
snapshots.
> Infinite waiting on lock acquisition by snapshot can result in unresponsive
> master
> ----------------------------------------------------------------------------------
>
> Key: HBASE-28271
> URL: https://issues.apache.org/jira/browse/HBASE-28271
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 3.0.0-alpha-4, 2.4.17, 2.5.7
> Reporter: Viraj Jasani
> Assignee: Viraj Jasani
> Priority: Major
> Attachments: image.png
>
>
> When a region is stuck in transition for significant time, any attempt to
> take snapshot on the table would keep master handler thread in forever
> waiting state. As part of the creating snapshot on enabled or disabled table,
> in order to get the table level lock, LockProcedure is executed but if any
> region of the table is in transition, LockProcedure could not be executed by
> the snapshot handler, resulting in forever waiting until the region
> transition is completed, allowing the table level lock to be acquired by the
> snapshot handler.
> In cases where a region stays in RIT for considerable time, if enough
> attempts are made by the client to create snapshots on the table, it can
> easily exhaust all handler threads, leading to potentially unresponsive
> master. Attached a sample thread dump.
> Proposal: The snapshot handler should not stay stuck forever if it cannot
> take table level lock, it should fail-fast.
> !image.png!
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