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From Guy Doulberg <>
Subject Distinct in hive
Date Tue, 25 Jan 2011 16:25:36 GMT
We made a query in hive, that calculates the number of distinct values in a  group by.
On small portion of data it worked well, however when we ran the query over large portion
of data, we failed because OutOfMemory in some of the reducers.

We wonder how is the distinct operator works in HIVE? Does it use some sort of data structure
that its size is proportional to the number of distinct values?

Many thanks

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