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From Billie J Rinaldi <>
Subject Re: grouping
Date Sat, 11 Feb 2012 00:43:56 GMT
When you add an aggregator or combiner to a scan, it doesn't aggregate all the values in the
scan range. It provides an aggregated value for each unique cell (i.e. row, column family,
column qualifier, and column visibility tuple). It aggregates together values for keys that
only differ by timestamp.

If there is a VersioningIterator configured for the table (which there is by default), make
sure to set the aggregator or combiner at a lower "priority" than the versioning, so that
it occurs first -- or just remove the VersioningIterator from the table.


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