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Posted to common-dev@hadoop.apache.org by "Devaraj Das (JIRA)" <ji...@apache.org> on 2007/03/26 20:16:32 UTC
[jira] Commented: (HADOOP-1159) Reducers hang when map output file
has a checksum error
[ https://issues.apache.org/jira/browse/HADOOP-1159?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12484176 ]
Devaraj Das commented on HADOOP-1159:
-------------------------------------
Although this issue can be solved by handling the NPE, this and other such problems, in general, can be handled by a fix for HADOOP-1158.
> Reducers hang when map output file has a checksum error
> -------------------------------------------------------
>
> Key: HADOOP-1159
> URL: https://issues.apache.org/jira/browse/HADOOP-1159
> Project: Hadoop
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.12.2
> Reporter: Nigel Daley
>
> Two reduces hung in our sort benchmark. They always fail to get map outputs from node X due to checksum error when the map outputs are read at that node resulting in a NullPointerException on node X. This leads to constant failures on the two fetching reduces.
> 2007-03-26 00:02:57,082 WARN org.apache.hadoop.fs.FileSystem: Moving bad file /e/c/k/hqa/tb/tmp/mapred/local2/task_0002_m_022488_0/file.out to /e/c/bad_files/file.out.542279301
> 2007-03-26 00:02:57,083 INFO org.apache.hadoop.fs.FSInputChecker: Found checksum error: org.apache.hadoop.fs.ChecksumException: Checksum error: /e/c/k/hqa/tb/tmp/mapred/local2/task_0002_m_022488_0/file.out at 106484224
> at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.verifySum(ChecksumFileSystem.java:254)
> at org.apache.hadoop.fs.ChecksumFileSystem$FSInputChecker.readBuffer(ChecksumFileSystem.java:211)
> 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.read1(BufferedInputStream.java:258)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> at java.io.DataInputStream.read(DataInputStream.java:132)
> at org.apache.hadoop.mapred.TaskTracker$MapOutputServlet.doGet(TaskTracker.java:1659)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
> at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:427)
> at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:475)
> at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:567)
> at org.mortbay.http.HttpContext.handle(HttpContext.java:1565)
> at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:635)
> at org.mortbay.http.HttpContext.handle(HttpContext.java:1517)
> at org.mortbay.http.HttpServer.service(HttpServer.java:954)
> at org.mortbay.http.HttpConnection.service(HttpConnection.java:814)
> at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:981)
> at org.mortbay.http.HttpConnection.handle(HttpConnection.java:831)
> at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:244)
> at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
> at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)
> 2007-03-26 00:02:57,083 WARN /: /mapOutput?map=task_0002_m_022488_0&reduce=1542:
> java.lang.NullPointerException
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