[PIG-1784] ERROR 1081: Cannot cast to map. Expected bytearray but received: bag

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.8.0
• Fix Version/s: 0.8.1
• Assignee: Daniel Dai
• Reporter: Vivek Padmanabhan
• Created: 04/Jan/11 12:41
• Updated: 25/Apr/11 21:27
• Resolved: 04/Mar/11 16:44

Description

The below script was working fine with Pig 0.7. But in Pig 0.8 it is throwing exception.

A = LOAD 'small_input' USING PigStorage(',') AS (spaceid);
B = foreach A generate spaceid;
X = load 'main_data/part-00149' using MapLoader() as (map1, map2, map3);
X = LIMIT X 10;
Raw = foreach X generate map1#'yuid' as type, flatten(map3#'timespent_sessions') as timespent;
Mapping = join Raw by timespent#'p', B by spaceid USING 'replicated' parallel 50;
store Mapping into 'out';
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total 3 Mr jobs ar e planned for this script.The reducers of the second MR job is failing with the below exception :

WARN org.apache.hadoop.mapred.Child: Error running child
org.apache.pig.backend.executionengine.ExecException: ERROR 1081: Cannot cast to map. Expected bytearray but received: bag
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POCast.getNext(POCast.java:942)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POMapLookUp.processInput(POMapLookUp.java:87)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POMapLookUp.getNext(POMapLookUp.java:98)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POMapLookUp.getNext(POMapLookUp.java:117)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POLocalRearrange.getNext(POLocalRearrange.java:288)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POFRJoin.getNext(POFRJoin.java:252)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.processInput(PhysicalOperator.java:276)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:240)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.runPipeline(PigMapReduce.java:433)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.processOnePackageOutput(PigMapReduce.java:401)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.reduce(PigMapReduce.java:381)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Reduce.reduce(PigMapReduce.java:251)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:176)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:572)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:414)
at org.apache.hadoop.mapred.Child$4.run(Child.java:242)
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:1062)
at org.apache.hadoop.mapred.Child.main(Child.java:236)
Caused by: java.lang.ClassCastException: org.apache.pig.data.DefaultDataBag cannot be cast to org.apache.pig.data.DataByteArray
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POCast.getNext(POCast.java:928)