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https://issues.apache.org/jira/browse/HIVE-14065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15340856#comment-15340856
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Mohit Sabharwal commented on HIVE-14065:
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[~alangates], I think Colin is requesting an API that effectively takes a
(shared?) lock at the metastore level, disallowing all writes
that currently each need an exclusive Zk lock.
> Provide an API for making Hive read-only for a short period
> -----------------------------------------------------------
>
> Key: HIVE-14065
> URL: https://issues.apache.org/jira/browse/HIVE-14065
> Project: Hive
> Issue Type: Improvement
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
>
> HIVE-7973 added a notification log which allows clients to do incremental
> replication of the Hive metastore. However, it is a challenge to get the
> initial state of the Hive database. Using existing APIs may give us an
> inconsistent state. For example, if a Hive table is renamed while we're
> loading all tables, we may miss that information.
> The easiest way to fix this would be to provide an API for making Hive
> read-only for a short period. This locking API would come with a timeout so
> that if the locker failed, the system would not stay down. It would return
> an ID which uniquely identified the lock instance. The read-only lock itself
> could be implemented by taking all the ZooKeeper locks. The RPC for removing
> the lock would return back a status indicating whether the lock had timed out
> before being removed or not. If it had timed out, we could retry our
> snapshot loading process with a longer timeout period.
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