[HBASE-543] A region's state is kept in several places in the master opening the possibility for race conditions

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.1.0, 0.1.1, 0.2.0
• Fix Version/s: 0.19.0
• Component/s: master
• Assignee: Jim Kellerman
• Reporter: Jim Kellerman
• Created: 24/Mar/08 22:26
• Updated: 13/Sep/09 22:26
• Resolved: 24/Dec/08 01:38

Description

A region's state exists in multiple maps in the RegionManager: unassignedRegions, pendingRegions, regionsToClose, closingRegions, regionsToDelete, etc.

One of these race conditions was found in HBASE-534.

For HBase-0.1.x, we should just patch the holes we find.

The ultimate solution (which requires a lot of changes in HMaster) should be applied to HBase trunk.

Proposed solution:

Create a class that encapsulates a region's state and provide synchronized access to the class that validates state changes.
There should be a single structure that holds regions in these transitional states and it should be a synchronized collection of some kind.

Issue Links

• blocks: HBASE-546 Use Zookeeper in HBase
• blocks: HBASE-504 Allow HMsg's carry a payload: e.g. exception that happened over on the remote side.
• is related to: HBASE-549 Don't CLOSE region if message is not from server that opened it or is opening it
• is related to: HBASE-1077 Master does not reassign regions closed while opening
• relates to: HBASE-599 CME iterating return from ServerManager.getMarkedToClose

Sub-Tasks

• Regionserver attempting to open reassigned region but master ignoring, thinks region is still closing: Closed
• Region assigned to two regionservers after split: Closed