[HDFS-4813] BlocksMap may throw NullPointerException during shutdown

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha1
• Fix Version/s: 2.1.0-beta
• Component/s: namenode
• Hadoop Flags: Reviewed
• Assignee: Jing Zhao
• Reporter: Tsz-wo Sze
• Created: 10/May/13 17:39
• Updated: 12/May/16 18:13
• Resolved: 15/May/13 02:19

Description

TestBlocksWithNotEnoughRacks may fail occasionally due to the bug:

java.lang.AssertionError: Test resulted in an unexpected exit
	at org.apache.hadoop.hdfs.MiniDFSCluster.shutdown(MiniDFSCluster.java:1416)
	at org.apache.hadoop.hdfs.server.blockmanagement.TestBlocksWithNotEnoughRacks.__CLR3_0_226e5kj1ntz(TestBlocksWithNotEnoughRacks.java:373)
	at org.apache.hadoop.hdfs.server.blockmanagement.TestBlocksWithNotEnoughRacks.testReduceReplFactorDueToRejoinRespectsRackPolicy(TestBlocksWithNotEnoughRacks.java:330)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	...

At the end of the log:

2013-05-10 13:05:53,828 FATAL hdfs.MiniDFSCluster (MiniDFSCluster.java:shutdown(1413)) - Test resulted in an unexpected exit
org.apache.hadoop.util.ExitUtil$ExitException: java.lang.NullPointerException
	at org.apache.hadoop.hdfs.server.blockmanagement.BlocksMap.getBlockCollection(BlocksMap.java:77)
	at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeReplicationWorkForBlocks(BlockManager.java:1153)
	at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeReplicationWork(BlockManager.java:1128)
	at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeDatanodeWork(BlockManager.java:3127)
	at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager$ReplicationMonitor.run(BlockManager.java:3089)
	at java.lang.Thread.run(Thread.java:662)
	...

Issue Links

• relates to: HDFS-4840 ReplicationMonitor gets NPE during shutdown