Wow, I was pretty sure to have tested it, but apparently not. The reason
for the NPE seems to be the @MonitoredUDF
You can reproduced it with the following code:
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import org.apache.hadoop.conf.Configuration;
import org.apache.pig.EvalFunc;
import org.apache.pig.builtin.MonitoredUDF;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.util.UDFContext;
@MonitoredUDF(timeUnit = TimeUnit.HOURS, duration = 3, intDefault = 1)
public class TestJobConf extends EvalFunc<Tuple> {
public TestJobConf() {
}
@Override
public Tuple exec(Tuple tuple) throws IOException {
if (tuple == null || tuple.size() == 0) {
return null;
}
Configuration jobConf;
jobConf = UDFContext.getUDFContext().getJobConf();
System.err.println(jobConf.toString());
return null;
}
}
Log from the Task:
2013-10-30 19:24:09,516 ERROR TestJobConf:
java.util.concurrent.ExecutionException:
java.lang.NullPointerException
2013-10-30 19:24:10,388 ERROR TestJobConf:
java.util.concurrent.ExecutionException:
java.lang.NullPointerException
2013-10-30 19:24:10,880 ERROR TestJobConf:
java.util.concurrent.ExecutionException:
java.lang.NullPointerException
2013-10-30 19:24:11,512 ERROR TestJobConf:
java.util.concurrent.ExecutionException:
java.lang.NullPointerException
2013-10-30 19:24:12,264 ERROR TestJobConf:
java.util.concurrent.ExecutionException:
java.lang.NullPointerException
Without the MonitoredUDF Annotation the log output is:
Configuration: core-default.xml, core-site.xml, mapred-default.xml,
mapred-site.xml, hdfs-default.xml, hdfs-site.xml, .....
Seems like a bug.
2013/10/30 Pradeep Gollakota <pradeep...@gmail.com>
> Are you able to post your UDF (or at least a sanitized version)?
>
>
> On Wed, Oct 30, 2013 at 10:46 AM, Henning Kropp <henning.kr...@gmail.com
> >wrote:
>
> > Hi,
> >
> > thanks for your reply. I read about the expected behavior on the
> front-end
> > and I am getting the NPE on the back-end. The Mappers log the Exception
> > during Execution.
> >
> > I am currently digging through debug messages. What to look out for?
> There
> > are bunch of
> >
> > [main] DEBUG org.apache.hadoop.conf.Configuration - java.io.IOException:
> > config()
> >
> > log messages. But I recall them as being "normal" for reasons I don't
> > remember.
> >
> > Regards
> >
> >
> > 2013/10/30 Cheolsoo Park <piaozhe...@gmail.com>
> >
> > > Hi,
> > >
> > > Are you getting NPE on the front-end or the back-end? Sounds like
> jobConf
> > > is not added to UDFContext, which is expected on the front-end. Please
> > see
> > > the comments in getJobConf() and addJobConf() in the source code:
> > >
> > >
> > >
> >
> https://svn.apache.org/repos/asf/pig/trunk/src/org/apache/pig/impl/util/UDFContext.java
> > >
> > > Thanks,
> > > Cheolsoo
> > >
> > >
> > > On Wed, Oct 30, 2013 at 9:57 AM, Henning Kropp <
> henning.kr...@gmail.com
> > > >wrote:
> > >
> > > > Hi,
> > > >
> > > > I am stuck. In my UDF (Java) extends EvalFunc the following code
> throws
> > > and
> > > > NPE in exec(), when executed in -x mapred mode:
> > > >
> > > > Configuration jobConf = UDFContext.getUDFContext().getJobConf();
> > > > System.err.println(jobConf.toString());
> > > >
> > > > I did not find any useful information as why my JobConf is always
> null.
> > > All
> > > > I find is that this is the right way to get the JobConf in a UDF and
> > that
> > > > the behavior of what is returned when running locally (jira issue).
> > > >
> > > > Any ideas? I am running it on a very old Hadoop version 0.20.2 Are
> > there
> > > > some known issues? I use Pig 0.11.1
> > > >
> > > > Many thanks in advanced
> > > >
> > > > PS: Just found someone with the same issue
> > > >
> > http://stackoverflow.com/questions/18795008/accessing-hdfs-from-pig-udf
> > > >
> > >
> >
>
