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https://issues.apache.org/jira/browse/HBASE-5494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13269113#comment-13269113
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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.".
Hi Prakash.
Thanks for the comments! I'll chat with you on Monday about the potential
issue around handling connection loss (I was under impression that
RecoverableZookeeper handles that).
INLINE COMMENTS
src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWrapper.java:1336
Isn't this handled by RecoverableZooKeeper?
src/main/java/org/apache/hadoop/hbase/zookeeper/DistributedLock.java:112 This
is to verify that we are only releasing a lock that we ourselves acquire, and
that code doesn't (accidentally) release lock acquired by other
threads/processes.
src/main/java/org/apache/hadoop/hbase/zookeeper/DistributedLock.java:294 Good
catch, will handle this.
REVISION DETAIL
https://reviews.facebook.net/D2997
BRANCH
table_level_ddl_locks
> 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, D2997.4.patch, D2997.5.patch,
> D2997.6.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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