[PIG-1895] Class cast exception while projecting udf result

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.7.0, 0.8.0, 0.9.0
• Fix Version/s: 0.8.1
• Component/s: impl
• Assignee: Daniel Dai
• Reporter: Vivek Padmanabhan
• Created: 11/Mar/11 11:10
• Updated: 03/May/11 17:16
• Resolved: 03/May/11 17:16

Description

Class cast exception is thrown when I try to project the result from my udf. The udf has a defined schema DataType.BAG,DataType.LONG and DataType.INTEGER

The below is my script

Data = load 'file:/home/pvivek/Desktop/input' using PigStorage() as ( i: int );
AllData = group Data all parallel 1;
SampledData = foreach AllData generate org.vivek.TestEvalFunc(Data, 5) as rs;
SampledData1 = foreach SampledData generate rs.sampled;

Even though the output schema defines "sampled" as a data bag, while processing, instead of sending only the data bag generated from the UDF , the entire tuple was sent to the projection as result.

Exception recieved :
java.lang.ClassCastException: org.apache.pig.data.BinSedesTuple cannot be cast to org.apache.pig.data.DataBag
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.processInputBag(POProject.java:484)
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.getNext(POProject.java:197)
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.processInputBag(POProject.java:480)
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.getNext(POProject.java:197)
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:339)
	at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:291)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.runPipeline(PigMapReduce.java:434)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.processOnePackageOutput(PigMapReduce.java:402)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.reduce(PigMapReduce.java:382)
	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.reduce(PigMapReduce.java:1)
	at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:176)
	at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:566)
	at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:408)
	at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:216)

This issue is happening with 0.9/0.8 and 0.7

Issue Links

• relates to: PIG-1866 Dereference a bag within a tuple does not work