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https://issues.apache.org/jira/browse/HBASE-28271?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17798814#comment-17798814
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ruanhui commented on HBASE-28271:
---------------------------------
[~vjasani]
Our users don't need to specify nonce group and nonce for proc-v2 snapshot.
They are automatically populated when the high version client build the
snapshot request.
For the master, if there is no nonce in the snapshot request, it will think
that the request comes from a lower version client and will choose to take
zk-based snapshot.
So back to your question, no. But there is a test of zk-based snapshot. Please
see
org.apache.hadoop.hbase.master.procedure.TestSnapshotProcedureConcurrently for
details.
> 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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