[HBASE-18005] read replica: handle the case that region server hosting both primary replica and meta region is down

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.4.0, 2.0.0
• Hadoop Flags: Reviewed
• Assignee: Hua Xiang
• Reporter: Hua Xiang
• Created: 05/May/17 22:27
• Updated: 01/Aug/18 06:23
• Resolved: 06/Jun/17 16:08

Description

Identified one corner case in testing that when the region server hosting both primary replica and the meta region is down, the client tries to reload the primary replica location from meta table, it is supposed to clean up only the cached location for specific replicaId, but it clears caches for all replicas. Please see

https://github.com/apache/hbase/blob/master/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionImplementation.java#L813

Since it takes some time for regions to be reassigned (including meta region), the following may throw exception

https://github.com/apache/hbase/blob/master/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RpcRetryingCallerWithReadReplicas.java#L173

This exception needs to be caught and it needs to get cached location (in this case, the primary replica's location is not available). If there are cached locations for other replicas, it can still go ahead to get stale values from secondary replicas.

With meta replica, it still helps to not clean up the caches for all replicas as the info from primary meta replica is up-to-date.

Issue Links

• Is contained by: HBASE-18223 Track the effort to improve/bug fix read replica feature