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Posted to dev@pig.apache.org by "Thejas M Nair (JIRA)" <ji...@apache.org> on 2011/04/16 00:01:05 UTC
[jira] [Commented] (PIG-1997) define semantics of referring to a
column within bytearray column
[ https://issues.apache.org/jira/browse/PIG-1997?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13020448#comment-13020448 ]
Thejas M Nair commented on PIG-1997:
------------------------------------
Referring to a column in a bytearray column results in error, if the object is a DataByteArray -
{code}
grunt> cat bag.txt
1 {(1,2,3)}
4 {(4,5,6)}
grunt> l = load 'bag.txt' as (a, b);
grunt> f = foreach l generate b.$0;
grunt> dump f;
...
java.lang.ClassCastException: org.apache.pig.data.DataByteArray cannot be cast to org.apache.pig.data.Tuple
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.getNext(POProject.java:451)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.processInput(PhysicalOperator.java:290)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.getNext(POProject.java:158)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.getNext(POProject.java:333)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.getNext(PhysicalOperator.java:320)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:332)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:284)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.runPipeline(PigMapBase.java:261)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.map(PigMapBase.java:256)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.map(PigMapBase.java:58)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:621)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:177)
{code}
> define semantics of referring to a column within bytearray column
> ------------------------------------------------------------------
>
> Key: PIG-1997
> URL: https://issues.apache.org/jira/browse/PIG-1997
> Project: Pig
> Issue Type: Task
> Reporter: Thejas M Nair
>
> When column x is of type bytearray, the semantics of x.$0 is not clear.
> We need to define the behavior of this expression in the following cases -
> 1. Column type is bytearray and the actual object is DataByteArray.
> 2. Column type is bytearray and the actual object is either a Tuple or DataBag.
> When the bytearray column is an object of type DataByteArray, pig runtime tries to cast the object as a tuple and fails with a cast exception.
> I am not sure of the current behavior if the bytearray column actually contains a Tuple or DataBag object. (Needs to be tested).
> This is related to PIG-1281 .
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