Reducers hang when map output file has a checksum error
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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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