Here is a simple script to reproduce it

a = load 'test.dat' using PigStorage() as (nums:chararray);
b = load 'join.dat' using PigStorage('\u0001') as (number:chararray,text:chararray);
c = filter a by nums == '7';
d = join c by nums LEFT OUTER, b by number USING "skewed";
dump d;

==== test.dat ====
1
2
3
4
5

===== join.dat =====
1^Aone
2^Atwo
3^Athree

where ^A means Control-A charatcer used as a separator.

Complete stack trace of the error thrown my 3rd M/R job in the pipeline

java.lang.RuntimeException: Error in configuring object
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
at org.apache.hadoop.mapred.MapTask$OldOutputCollector.(MapTask.java:448)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:358)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:307)
at org.apache.hadoop.mapred.Child.main(Child.java:159)
Caused by: java.lang.reflect.InvocationTargetException
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.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
... 6 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: Empty samples file
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.partitioners.SkewedPartitioner.configure(SkewedPartitioner.java:128)
... 11 more
Caused by: java.lang.RuntimeException: Empty samples file
at org.apache.pig.backend.hadoop.executionengine.util.MapRedUtil.loadPartitionFile(MapRedUtil.java:128)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.partitioners.SkewedPartitioner.configure(SkewedPartitioner.java:125)
... 11 more

Modify the code to handle the empty input file being sampled for skewed join.

+1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12437818/PIG-1273.patch
against trunk revision 917827.

+1 @author. The patch does not contain any @author tags.

+1 tests included. The patch appears to include 3 new or modified tests.

+1 javadoc. The javadoc tool did not generate any warning messages.

+1 javac. The applied patch does not increase the total number of javac compiler warnings.

+1 findbugs. The patch does not introduce any new Findbugs warnings.

+1 release audit. The applied patch does not increase the total number of release audit warnings.

+1 core tests. The patch passed core unit tests.

+1 contrib tests. The patch passed contrib unit tests.

Test results: http://hudson.zones.apache.org/hudson/job/Pig-Patch-h7.grid.sp2.yahoo.net/223/testReport/
Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Pig-Patch-h7.grid.sp2.yahoo.net/223/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output: http://hudson.zones.apache.org/hudson/job/Pig-Patch-h7.grid.sp2.yahoo.net/223/console

This message is automatically generated.

+1