[HBASE-10704] BaseLoadBalancer#roundRobinAssignment() may add same region to assignment plan multiple times

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.99.0, hbase-10070
• Hadoop Flags: Reviewed
• Assignee: Ted Yu
• Reporter: Ted Yu
• Created: 08/Mar/14 00:35
• Updated: 21/Feb/15 23:33
• Resolved: 11/Mar/14 00:41

Description

I noticed the following exception in some unit tests:

2014-03-09 03:38:13,523 WARN  [s111-s2.cs1cloud.internal,57347,1394350359795-GeneralBulkAssigner-2] master.GeneralBulkAssigner$SingleServerBulkAssigner(232): Failed bulking assigning 18 region(s) to s111.internal,46094,1394350360588, and continue to bulk assign others
java.lang.NullPointerException
	at org.apache.hadoop.hbase.master.AssignmentManager.assign(AssignmentManager.java:1505)
	at org.apache.hadoop.hbase.master.GeneralBulkAssigner$SingleServerBulkAssigner.run(GeneralBulkAssigner.java:228)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:722)

Here is related code:

          Lock lock = locks.remove(encodedName);
          lock.unlock();

lock was null due to BaseLoadBalancer#roundRobinAssignment() adding same region to assignment plan multiple times.

This happens in computing lastFewRegions where cluster.wouldLowerAvailability() returns true.