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Pig >> mail # user >> Unable to load data using PigStorage that was previously stored using PigStorage


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Jerry Lam 2013-04-17, 01:28
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Ruslan Al-Fakikh 2013-04-17, 15:57
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Jerry Lam 2013-04-17, 17:11
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Ruslan Al-Fakikh 2013-04-17, 17:22
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Ruslan Al-Fakikh 2013-04-17, 17:24
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Jerry Lam 2013-04-17, 17:38
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Ruslan Al-Fakikh 2013-04-17, 19:26
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Jerry Lam 2013-04-17, 19:48
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Re: Unable to load data using PigStorage that was previously stored using PigStorage
The output:
({ ([c#11,d#22]),([c#33,d#44]) })
()
looks weird.

Jerry, maybe the problem is in using PigStorage. As its javadoc says:

A load function that parses a line of input into fields using a character
delimiter

So I guess this is just for simple csv lines.
But you are trying to load a complicated Map structure as it was formatted
by previous storing.
Probably you'll need to write your own Loader for this. Another hint: using
the -schema paramenter to PigStorage, but I am not sure it can help:(

Ruslan
On Wed, Apr 17, 2013 at 11:48 PM, Jerry Lam <[EMAIL PROTECTED]> wrote:

> Hi Rusian:
>
> I did a describe B followed by a dump B, the output is:
> B: {b: {()}}
>
> ({ ([c#11,d#22]),([c#33,d#44]) })
> ()
>
> but when I executed
>
> C = foreach B generate flatten(b);
>
> dump C;
>
> I got the exception again...
>
> 2013-04-17 15:47:39,933 [Thread-26] WARN
>  org.apache.hadoop.mapred.LocalJobRunner - job_local_0002
> java.lang.Exception: java.lang.ClassCastException:
> org.apache.pig.data.DataByteArray cannot be cast to
> org.apache.pig.data.DataBag
> at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:400)
> Caused by: java.lang.ClassCastException: org.apache.pig.data.DataByteArray
> cannot be cast to org.apache.pig.data.DataBag
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.processInputBag(POProject.java:586)
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POProject.getNext(POProject.java:250)
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.getNext(PhysicalOperator.java:334)
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:372)
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:297)
> at
>
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.runPipeline(PigGenericMapBase.java:283)
> at
>
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:278)
> at
>
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:64)
> at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:725)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:332)
> at
>
> org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:232)
> at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
> at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
> at java.util.concurrent.FutureTask.run(FutureTask.java:138)
> at
>
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
> at
>
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
> at java.lang.Thread.run(Thread.java:680)
>
>
> Best Regards,
>
> Jerry
>
>
> On Wed, Apr 17, 2013 at 3:26 PM, Ruslan Al-Fakikh <[EMAIL PROTECTED]
> >wrote:
>
> > I think that before doing the FLATTEN, you should be 100% sure that your
> > cast worked properly. Can you first DESCRIBE B and then DUMP B right
> away?
> > Or probably it just can't be cast in this way. Honestly I don't know
> > exactly how it works, but here:
> > http://pig.apache.org/docs/r0.10.0/basic.html#cast
> > I see that casting from a map to a bag should produce an error.
> > Hope that helps.
> >
> >
> > On Wed, Apr 17, 2013 at 9:38 PM, Jerry Lam <[EMAIL PROTECTED]> wrote:
> >
> > > Hi Rusian:
> > >
> > > Thanks for your help. I really appreciate it. It really puzzled me.
> > >
> > > I did a "describe B", the output is "B: {b: bytearray}".
> > >
> > > I then tried to cast it as suggested, I got:
> > > B = foreach A generate document#'b' as b:{};
> > > describe B;
> > > B: {b: {()}}
> > >
> > > Then I proceed with:
> > > C = foreach B generate flatten(b);
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Jerry Lam 2013-04-18, 14:37
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Jerry Lam 2013-04-18, 14:43
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Prashant Kommireddi 2013-04-18, 16:34
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Jerry Lam 2013-04-18, 21:14
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Prashant Kommireddi 2013-04-18, 21:41
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Jerry Lam 2013-04-18, 22:57
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Ruslan Al-Fakikh 2013-04-19, 20:56
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Jerry Lam 2013-04-20, 00:39
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Prashant Kommireddi 2013-04-18, 06:56