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Posted to common-dev@hadoop.apache.org by "Hairong Kuang (JIRA)" <ji...@apache.org> on 2007/03/15 21:56:09 UTC
[jira] Commented: (HADOOP-1123) LocalFileSystem gets a
NullPointerException when tries to recover from ChecksumError
[ https://issues.apache.org/jira/browse/HADOOP-1123?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12481312 ]
Hairong Kuang commented on HADOOP-1123:
---------------------------------------
When a checksumed file system tries to recover from a ChecksumError, it first reports the checksum error and then tries to read from a different replica.
For the local file system, it closes the input stream when reporting checksum error. In read retry, it does a seek on the closed input stream and thus causes a NPE.
One solution to this problem is not to retry reading for the local file system. We could let reportCheckError returns a flag indicating if we want to retry or not.
> LocalFileSystem gets a NullPointerException when tries to recover from ChecksumError
> ------------------------------------------------------------------------------------
>
> Key: HADOOP-1123
> URL: https://issues.apache.org/jira/browse/HADOOP-1123
> Project: Hadoop
> Issue Type: Bug
> Components: fs
> Affects Versions: 0.12.0
> Reporter: Hairong Kuang
> Assigned To: Hairong Kuang
> Fix For: 0.13.0
>
>
> NullPointerException occurs when run a large sort
> java.lang.NullPointerException
> at org.apache.hadoop.fs.FSDataInputStream$Buffer.seek(FSDataInputStream.java:74)
> at org.apache.hadoop.fs.FSDataInputStream.seek(FSDataInputStream.java:121)
> at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.readBuffer(ChecksumFileSystem.java:221)
> at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.read(ChecksumFileSystem.java:167)
> at org.apache.hadoop.fs.FSDataInputStream$PositionCache.read(FSDataInputStream.java:41)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
> at org.apache.hadoop.fs.FSDataInputStream$Buffer.read(FSDataInputStream.java:93)
> at java.io.DataInputStream.readInt(DataInputStream.java:370)
> at org.apache.hadoop.io.SequenceFile$Reader.nextRawKey(SequenceFile.java:1616)
> at org.apache.hadoop.io.SequenceFile$Sorter$SegmentDescriptor.nextRawKey(SequenceFile.java:2567)
> at org.apache.hadoop.io.SequenceFile$Sorter$MergeQueue.next(SequenceFile.java:2353)
> at org.apache.hadoop.mapred.ReduceTask$ValuesIterator.getNext(ReduceTask.java:180)
> at org.apache.hadoop.mapred.ReduceTask$ValuesIterator.next(ReduceTask.java:149)
> at org.apache.hadoop.mapred.lib.IdentityReducer.reduce(IdentityReducer.java:41)
> at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:313)
> at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:1445)
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