[HADOOP-1911] infinite loop in dfs -cat command.

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.13.1, 0.14.3
• Fix Version/s: 0.17.0
• Hadoop Flags: Reviewed
• Assignee: Christopher Douglas
• Reporter: Koji Noguchi
• Created: 17/Sep/07 22:09
• Updated: 08/Jul/09 16:42
• Resolved: 04/Apr/08 23:31

Description

[knoguchi]$ hadoop dfs -cat fileA
07/09/13 17:36:02 INFO fs.DFSClient: Could not obtain block 0 from any node:
java.io.IOException: No live nodes contain current block
07/09/13 17:36:20 INFO fs.DFSClient: Could not obtain block 0 from any node:
java.io.IOException: No live nodes contain current block
[repeats forever]

Setting one of the Debug statement to Warn, it kept on showing

 
 WARN org.apache.hadoop.fs.DFSClient: Failed to connect
to /99.99.999.9 :11111:java.io.IOException: Recorded block size is 7496, but
datanode reports size of 0
	at org.apache.hadoop.dfs.DFSClient$DFSInputStream.blockSeekTo(DFSClient.java:690)
	at org.apache.hadoop.dfs.DFSClient$DFSInputStream.read(DFSClient.java:771)
	at org.apache.hadoop.fs.FSDataInputStream$PositionCache.read(FSDataInputStream.java:41)
	at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
	at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
	at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
	at java.io.DataInputStream.readFully(DataInputStream.java:178)
	at java.io.DataInputStream.readFully(DataInputStream.java:152)
	at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.(ChecksumFileSystem.java:123)
	at org.apache.hadoop.fs.ChecksumFileSystem.open(ChecksumFileSystem.java:340)
	at org.apache.hadoop.fs.FileSystem.open(FileSystem.java:259)
	at org.apache.hadoop.util.CopyFiles$FSCopyFilesMapper.map(CopyFiles.java:466)
	at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:48)
	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:186)
	at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:1707)

Turns out fileA was corrupted. Fsck showed crc file of 7496 bytes, but when I searched for the blocks on each node, 3 replicas were all size 0.

Not sure how it got corrupted, but it would be nice if the dfs command fail instead of getting into an infinite loop.

Issue Links

• is related to: HADOOP-83 infinite retries accessing a missing block
• is related to: HDFS-127 DFSClient block read failures cause open DFSInputStream to become unusable
• is related to: HDFS-378 DFSClient should track failures by datanode across all streams