[HIVE-14065] Provide an API for making Hive read-only for a short period

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Colin McCabe
• Reporter: Colin McCabe
• Created: 20/Jun/16 23:15
• Updated: 01/Oct/19 22:07

Description

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.

Issue Links

• relates to: SENTRY-1371 Rework fetching Hive Paths state