[HBASE-6228] Fixup daughters twice cause daughter region assigned twice

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Fix Version/s: 0.95.0
• Component/s: master
• Hadoop Flags: Reviewed
• Assignee: Chunhui Shen
• Reporter: Chunhui Shen
• Created: 18/Jun/12 06:10
• Updated: 23/Sep/13 18:30
• Resolved: 03/Oct/12 22:14

Description

First, how fixup daughters twice happen?
1.we will fixupDaughters at the last of HMaster#finishInitialization
2.ServerShutdownHandler will fixupDaughters when reassigning region through ServerShutdownHandler#processDeadRegion

When fixupDaughters, we will added daughters to .META., but it coudn't prevent the above case, because FindDaughterVisitor.

The detail is as the following:
Suppose region A is a splitted parent region, and its daughter region B is missing

1.First, ServerShutdownHander thread fixup daughter, so add daughter region B to .META. with serverName=null, and assign the daughter.

2.Then, Master's initialization thread will also find the daughter region B is missing and assign it. It is because FindDaughterVisitor consider daughter is missing if its serverName=null

Issue Links

• relates to: HBASE-6381 AssignmentManager should use the same logic for clean startup and failover