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https://issues.apache.org/jira/browse/HBASE-5494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13268007#comment-13268007
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Phabricator commented on HBASE-5494:
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avf has commented on the revision "[jira] [HBASE-5494] [89-fb] Table-level
locks for schema changing operations.".
@stack I'm currently thinking over this. I think it makes sense to have a
separate JIRA (or perhaps another patch for the same JIRA?) to address this --
acquiring a table lock for merges and splits makes sense to me. Since a table
lock would only serve to prevent table schema modifications (disabling/enabling
schemas), it would be okay if the lock remains "stuck" during a split -- as
long as there is a way to recover from this.
I am thinking of the right way to remove persistent locks in general from a
crash -- will get back to you with some thoughts on the matter.
REVISION DETAIL
https://reviews.facebook.net/D2997
> Introduce a zk hosted table-wide read/write lock so only one table operation
> at a time
> --------------------------------------------------------------------------------------
>
> Key: HBASE-5494
> URL: https://issues.apache.org/jira/browse/HBASE-5494
> Project: HBase
> Issue Type: Improvement
> Reporter: stack
> Attachments: D2997.3.patch
>
>
> I saw this facility over in the accumulo code base.
> Currently we just try to sort out the mess when splits come in during an
> online schema edit; somehow we figure we can figure all possible region
> transition combinations and make the right call.
> We could try and narrow the number of combinations by taking out a zk table
> lock when doing table operations.
> For example, on split or merge, we could take a read-only lock meaning the
> table can't be disabled while these are running.
> We could then take a write only lock if we want to ensure the table doesn't
> change while disabling or enabling process is happening.
> Shouldn't be too hard to add.
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