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Hadoop, mail # user - 100x slower mapreduce compared to pig


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Re: 100x slower mapreduce compared to pig
Mohit Anchlia 2012-02-29, 17:27
I am going to try few things today. I have a JAXBContext object that
marshals the xml, this is static instance but my guess at this point is
that since this is in separate jar then the one where job runs and I used
DistributeCache.addClassPath this context is being created on every call
for some reason. I don't know why that would be. I am going to create this
instance as static in the mapper class itself and see if that helps. I also
add debugs. Will post the results after try it out.

On Tue, Feb 28, 2012 at 4:18 PM, Prashant Kommireddi <[EMAIL PROTECTED]>wrote:

> It would be great if we can take a look at what you are doing in the UDF vs
> the Mapper.
>
> 100x slow does not make sense for the same job/logic, its either the Mapper
> code or may be the cluster was busy at the time you scheduled MapReduce
> job?
>
> Thanks,
> Prashant
>
> On Tue, Feb 28, 2012 at 4:11 PM, Mohit Anchlia <[EMAIL PROTECTED]
> >wrote:
>
> > I am comparing runtime of similar logic. The entire logic is exactly same
> > but surprisingly map reduce job that I submit is 100x slow. For pig I use
> > udf and for hadoop I use mapper only and the logic same as pig. Even the
> > splits on the admin page are same. Not sure why it's so slow. I am
> > submitting job like:
> >
> > java -classpath
> >
> >
> .:analytics.jar:/hadoop-0.20.2-cdh3u3/lib/*:/root/.mohit/hadoop-0.20.2-cdh3u3/*:common.jar
> > com.services.dp.analytics.hadoop.mapred.FormMLProcessor
> >
> >
> /examples/testfile40.seq,/examples/testfile41.seq,/examples/testfile42.seq,/examples/testfile43.seq,/examples/testfile44.seq,/examples/testfile45.seq,/examples/testfile46.seq,/examples/testfile47.seq,/examples/testfile48.seq,/examples/testfile49.seq
> > /examples/output1/
> >
> > How should I go about looking the root cause of why it's so slow? Any
> > suggestions would be really appreciated.
> >
> >
> >
> > One of the things I noticed is that on the admin page of map task list I
> > see status as "hdfs://dsdb1:54310/examples/testfile40.seq:0+134217728"
> but
> > for pig the status is blank.
> >
>