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From Otis Gospodnetic <otis_gospodne...@yahoo.com>
Subject Default Combiner or default combining behaviour?
Date Thu, 20 Mar 2008 22:56:47 GMT
Hi,

The MapReduce tutorial mentions Combiners only in passing.  Is there a default Combiner or
default combining behaviour?

Concretely, I want to make sure that records are not getting combined behind the scenes in
some way without me seeing it, and causing me to lose data.  For instance, if there is a default
Combiner or default combining behaviour that collapses multiple records with identical keys
and values into a single record, I'd like to avoid that.  Instead of blindly collapsing identical
records, I'd want to aggregate their values and emit the aggregate.

Thanks,
Otis
--
Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch



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