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From Philip Tromans <philip.j.trom...@gmail.com>
Subject Re: Map side aggregations
Date Wed, 23 May 2012 09:15:38 GMT
Hi Ranjith,

I haven't checked the code (so this might not be true), but I think that
the map side aggregation stuff uses it's own hash map within the map phase
to do the aggregation, instead of using a combiner, so you wouldn't expect
to see any combine input records. Have a look for parameters
like hive.groupby.mapaggr.checkinterval, and the associated documentation
will explain how it all works.

Cheers,

Phil.

On 23 May 2012 02:44, Ranjith <ranjith.raghunath1@gmail.com> wrote:

> Thanks Matt. I am not performing a join so does that matter? What does
> this local task do?
>
> Thanks,
> Ranjith
>
> On May 22, 2012, at 8:17 PM, "Tucker, Matt" <Matt.Tucker@disney.com>
> wrote:
>
> Try setting hive.auto.convert.join to true.  The CLI will have a local
> task before it starts a map-reduce job on the cluster.
>
> Matt
>
>
>
> On May 22, 2012, at 8:43 PM, "Raghunath, Ranjith" <
> Ranjith.Raghunath1@usaa.com> wrote:
>
>  I have the parameter hive.map.aggr set to true. However, when I look at
> the counters associated with the map tasks I notice the following “Combine
> input records 0”. I am interpreting this as a failure to perform the map
> side aggregation. Is that accurate? Is this option not working in hive
> 0.7.1?
>
> Thanks,
> Ranjith
>
>
>
>
>

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