[PIG-894] order-by fails when input is empty

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.4.0
• Fix Version/s: 0.6.0
• Hadoop Flags: Reviewed
• Assignee: Daniel Dai
• Reporter: Thejas Nair
• Created: 21/Jul/09 18:55
• Updated: 24/Mar/10 22:15
• Resolved: 09/Oct/09 18:08

Description

grunt> l = load 'students.txt' ;
grunt> f = filter l by 1 == 2;
grunt> o = order f by $0 ;
grunt> dump o;

This results in 3 MR jobs . The 2nd (sampling) MR creates empty sample file, and 3rd MR (order-by) fails with following error in Map job -

java.lang.RuntimeException: java.lang.RuntimeException: Empty samples file
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.partitioners.WeightedRangePartitioner.configure(WeightedRangePartitioner.java:104)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:58)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:82)
at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.(MapTask.java:348)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:193)
at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:2207)
Caused by: java.lang.RuntimeException: Empty samples file
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.partitioners.WeightedRangePartitioner.configure(WeightedRangePartitioner.java:89)
... 5 more