[MAPREDUCE-420] FileNotFoundException when finishing a profiled task that doesn't generate an output file

• Type: Bug
• Status: Resolved
• Priority: Trivial
• Resolution: Duplicate
• Assignee: Rodrigo Schmidt
• Reporter: Rodrigo Schmidt
• Created: 06/Feb/09 00:59
• Updated: 13/Sep/11 15:55
• Resolved: 06/Jan/10 19:27

Description

When running a hadoop job with mapred.task.profile=true, hadoop assumes that mapred.task.profile.params contains a "%s" that can be changed for a file name that will be created by the profiler containing its text output. If the profiler doesn't generate such an output file, profiled tasks will raise a FileNotFound exception at the end of their execution:

09/02/05 15:39:10 INFO mapred.JobClient: map 100% reduce 0%
09/02/05 15:39:10 INFO mapred.JobClient: Communication problem with server: java.io.FileNotFoundException: http://machine1:50060/tasklog?plaintext=true&taskid=attempt_200901221838_0043_m_000000_0&filter=profile
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1239)
at org.apache.hadoop.mapred.JobClient.downloadProfile(JobClient.java:1089)
at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1166)
at JavaCat.main(JavaCat.java:46)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:165)
at org.apache.hadoop.mapred.JobShell.run(JobShell.java:54)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
at org.apache.hadoop.mapred.JobShell.main(JobShell.java:68)

This happens because it's assumed users will use the default hprof profiler, which actually allows you to set the output file name. Not all profilers are like that and some don't have any option to create a text output log at all or don't allow you to change the name of the output file. In my case, I'm a profiler that doesn't generate text output and only allows you to set the output directory for the snapshot files it generates.

Issue Links

• is duplicated by: MAPREDUCE-105 Handling of mapred.task.profile.params is hprof specific
• is related to: HADOOP-2367 Get representative hprof information from tasks