[HADOOP-3320] NPE in NetworkTopology.getDistance()

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.14.0
• Fix Version/s: 0.18.0
• Hadoop Flags: Reviewed
• Assignee: Hairong Kuang
• Reporter: Konstantin Shvachko
• Created: 28/Apr/08 21:14
• Updated: 02/May/13 02:29
• Resolved: 19/Jun/08 20:35

Description

I am seeing the following exception:

08/04/28 20:15:09 ERROR dfs.NNThroughputBenchmark: java.lang.NullPointerException
	at org.apache.hadoop.net.NetworkTopology.getDistance(NetworkTopology.java:443)
	at org.apache.hadoop.dfs.ReplicationTargetChooser.getPipeline(ReplicationTargetChooser.java:457)
	at org.apache.hadoop.dfs.ReplicationTargetChooser.chooseTarget(ReplicationTargetChooser.java:126)
	at org.apache.hadoop.dfs.ReplicationTargetChooser.chooseTarget(ReplicationTargetChooser.java:72)
	at org.apache.hadoop.dfs.FSNamesystem.getAdditionalBlock(FSNamesystem.java:1140)
	at org.apache.hadoop.dfs.NameNode.addBlock(NameNode.java:300)
	at org.apache.hadoop.dfs.NNThroughputBenchmark$BlockReportStats.addBlocks(NNThroughputBenchmark.java:786)
	at org.apache.hadoop.dfs.NNThroughputBenchmark$BlockReportStats.generateInputs(NNThroughputBenchmark.java:775)
	at org.apache.hadoop.dfs.NNThroughputBenchmark$OperationStatsBase.benchmark(NNThroughputBenchmark.java:203)
	at org.apache.hadoop.dfs.NNThroughputBenchmark.runBenchmark(NNThroughputBenchmark.java:1035)
	at org.apache.hadoop.dfs.NNThroughputBenchmark.main(NNThroughputBenchmark.java:1053)

It looks like the problem is in NetworkTopology.chooseRandom(String, String), which returns null in certain cases, but the value returned is never checked for null.

Issue Links

• depends upon: HADOOP-3513 Improve NNThroughputBenchmark log messages.