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Phabricator commented on HBASE-5494: ------------------------------------ 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. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira