[HBASE-8096] [replication] NPE while replicating a log that is acquiring a new block from HDFS

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.94.5
• Fix Version/s: 0.98.0, 0.94.7, 0.95.1
• Hadoop Flags: Reviewed
• Assignee: Dave Latham
• Reporter: Ian Friedman
• Created: 13/Mar/13 22:38
• Updated: 27/Apr/13 15:55
• Resolved: 13/Apr/13 17:07

Description

We're getting an NPE during replication, which causes replication for that RegionServer to stop until we restart it.

2013-03-10 12:49:12,679 ERROR org.apache.hadoop.hbase.replication.regionserver.ReplicationSource: Unexpected exception in ReplicationSource, currentPath=hdfs://hmaster1:9000/hbase/.logs/hslave1177,60020,1362549511446/hslave1177%2C60020%2C1362549511446.1362944946489
java.lang.NullPointerException
        at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.updateBlockInfo(DFSClient.java:1882)
        at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.openInfo(DFSClient.java:1855)
        at org.apache.hadoop.hdfs.DFSClient$DFSInputStream.<init>(DFSClient.java:1831)
        at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:578)
        at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:154)
        at org.apache.hadoop.fs.FilterFileSystem.open(FilterFileSystem.java:108)
        at org.apache.hadoop.io.SequenceFile$Reader.openFile(SequenceFile.java:1495)
        at org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader$WALReader.openFile(SequenceFileLogReader.java:62)
        at org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1482)
        at org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1475)
        at org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1470)
        at org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader$WALReader.<init>(SequenceFileLogReader.java:55)
        at org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogReader.reset(SequenceFileLogReader.java:308)
        at org.apache.hadoop.hbase.replication.regionserver.ReplicationHLogReaderManager.openReader(ReplicationHLogReaderManager.java:69)
        at org.apache.hadoop.hbase.replication.regionserver.ReplicationSource.openReader(ReplicationSource.java:505)
        at org.apache.hadoop.hbase.replication.regionserver.ReplicationSource.run(ReplicationSource.java:313)

Some extra digging into the DataNode and NameNode logs makes this seem related to HBASE-7530 and HDFS-4380

Here's the relevant snipped portions of the RS, DN, and NN logs:

RS 2013-03-10 12:49:12,618 INFO org.apache.hadoop.hbase.replication.regionserver.ReplicationSourceManager: Going to report log #hslave1177%2C60020%2C1362549511446.1362944946489 for position 59670826 in hdfs://hmaster1:9000/hbase/.logs/hslave1177,60020,1362549511446/hslave1177%2C60020%2C1362549511446.1362944946489
RS 2013-03-10 12:49:12,621 DEBUG org.apache.hadoop.hbase.regionserver.LogRoller: HLog roll requested
RS 2013-03-10 12:49:12,623 DEBUG org.apache.hadoop.hbase.replication.regionserver.ReplicationSource: Replicated in total: 31500300
RS 2013-03-10 12:49:12,623 DEBUG org.apache.hadoop.hbase.replication.regionserver.ReplicationSource: Opening log for replication hslave1177%2C60020%2C1362549511446.1362944946489 at 59670826
NN 2013-03-10 12:49:12,627 INFO org.apache.hadoop.hdfs.StateChange: BLOCK* NameSystem.allocateBlock: /hbase/.logs/hslave1177,60020,1362549511446/hslave1177%2C60020%2C1362549511446.1362944946489. blk_6905758215335505153_656717631
RS 2013-03-10 12:49:12,679 ERROR org.apache.hadoop.hbase.replication.regionserver.ReplicationSource: Unexpected exception in ReplicationSource, currentPath=hdfs://hmaster1:9000/hbase/.logs/hslave1177,60020,1362549511446/hslave1177%2C60020%2C1362549511446.1362944946489
DN 2013-03-10 12:49:12,680 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Receiving block blk_6905758215335505153_656717631 src: /192.168.44.1:43503 dest: /192.168.44.1:50010
NN 2013-03-10 12:49:12,804 INFO org.apache.hadoop.hdfs.StateChange: BLOCK* NameSystem.fsync: file /hbase/.logs/hslave1177,60020,1362549511446/hslave1177%2C60020%2C1362549511446.1362944946489 for DFSClient_hb_rs_hslave1177,60020,1362549511446

Issue Links

• relates to: HDFS-4380 Opening a file for read before writer writes a block causes NPE
• relates to: HBASE-7530 [replication] Work around HDFS-4380 else we get NPEs