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https://issues.apache.org/jira/browse/PIG-595?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Viraj Bhat updated PIG-595:
---------------------------
Attachment: querypairs.txt
Input file
> Use of Combiner causes java.lang.ClassCastException in ForEach
> --------------------------------------------------------------
>
> Key: PIG-595
> URL: https://issues.apache.org/jira/browse/PIG-595
> Project: Pig
> Issue Type: Bug
> Components: impl
> Affects Versions: types_branch
> Reporter: Viraj Bhat
> Fix For: types_branch
>
> Attachments: querypairs.txt
>
>
> The following Pig script causes a ClassCastException when QueryPairs is used
> in the ForEach statement. This is due to the use of the combiner.
> {code}
> QueryPairs = load 'querypairs.txt' using PigStorage() as ( q1: chararray,
> q2: chararray );
> describe QueryPairs;
> QueryPairsGrouped = group QueryPairs by ( q1 );
> describe QueryPairsGrouped;
> QueryGroups = foreach QueryPairsGrouped generate
> group as q1,
> COUNT(QueryPairs) as paircount,
> QueryPairs as QueryPairs;
> describe QueryGroups;
> dump QueryGroups;
> {code}
> =================================================================================================================
> 2008-12-31 15:01:48,713 [main] ERROR
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.Launcher - Error
> message from task (map)
> task_200812151518_4922_m_000000java.lang.ClassCastException:
> org.apache.pig.data.DefaultDataBag cannot be cast to org.apache.pig.data.Tuple
> at
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POCombinerPackage.getNext(POCombinerPackage.java:122)
> at
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigCombiner$Combine.processOnePackageOutput(PigCombiner.java:152)
> at
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigCombiner$Combine.reduce(PigCombiner.java:143)
> at
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigCombiner$Combine.reduce(PigCombiner.java:57)
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.combineAndSpill(MapTask.java:904)
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.sortAndSpill(MapTask.java:785)
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.flush(MapTask.java:698)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:228)
> at
> org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:2207)
> =================================================================================================================
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