[HADOOP-1136] exception in UnderReplicatedBlocks:add when ther are more replicas of a block than required

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.12.2
• Fix Version/s: 0.13.0
• Assignee: Hairong Kuang
• Reporter: Dhruba Borthakur
• Created: 20/Mar/07 17:05
• Updated: 08/Jul/09 16:42
• Resolved: 11/Apr/07 08:27

Description

I was running a random writer followed by a sort when I saw this condition:

Exception in thread "org.apache.hadoop.dfs.FSNamesystem$ReplicationMonitor@187814" java.lang.ArrayIndexOutOfBoundsException: 3
at org.apache.hadoop.dfs.FSNamesystem$UnderReplicatedBlocks.add(FSNamesystem.java:447)
at org.apache.hadoop.dfs.FSNamesystem$UnderReplicatedBlocks.add(FSNamesystem.java:464)
at org.apache.hadoop.dfs.FSNamesystem.processPendingReplications(FSNamesystem.java:1891)
at org.apache.hadoop.dfs.FSNamesystem$ReplicationMonitor.run(FSNamesystem.java:1795)
at java.lang.Thread.run(Thread.java:619)

processPendingReplications is invoking neededReplications.add(). The add method then invokes add(block, 3, 4). This add method calls getPriority and that returns 3. Now, the call to priorityQueues[3].add() throws an OutOfBoundsException.