ClassCastException Exception when using Distinct UDF

[leiwang...@gmail.com]

A simple pig script to get the distinct elements of a gouped bag. 

data = LOAD  .............;
data_pro = FOREACH data GENERATE custid, ip, userid;
data_group = GROUP data_pro BY custid;
data_group_pro = FOREACH data_group GENERATE group, Distinct(data_pro.userid), 
Distinct(data_pro.ip); 

But there's error: 
java.lang.ClassCastException: org.apache.pig.data.SingleTupleBag cannot be cast 
to org.apache.pig.data.Tuple
        at org.apache.pig.builtin.Distinct$Initial.exec(Distinct.java:86)
        at org.apache.pig.builtin.Distinct$Initial.exec(Distinct.java:75)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:337)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:376)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.getNext(PhysicalOperator.java:354)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:372)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:297)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.processInput(PhysicalOperator.java:308)
        at 
org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POLocalRearrange.getNext(POLocalRearrange.java:263)
        at 
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.runPipeline(PigGenericMapBase.java:283)
        at 
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:278)
        at 
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:64)
        at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:140)
        at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:672)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:330)
        at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:396)
        at 
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1408)
        at org.apache.hadoop.mapred.Child.main(Child.java:262)
I am using pig 0.11 which is packaged in chd4.3.2, where i can see the source 
code:  
http://grepcode.com/file/repository.cloudera.com/content/repositories/releases/org.apache.pig/pig/0.11.0-cdh4.3.2/org/apache/pig/builtin/Distinct.java
 
Any insight on this?Thanks,Lei


leiwang...@gmail.com