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Hive, mail # user - MapSide join in Hive


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MapSide join in Hive
Viraj Bhat 2010-06-24, 17:43
Hi all,

 I am joining 2 datasets, one is around 1.5TB in size and the other is
around 350MB in size.

I wanted to do a Map Side join using "id" as the join column between the
two tables. I read about the Mapside join in Hive.

http://wiki.apache.org/hadoop/Hive/LanguageManual/Joins. Are there some
technical specs on Mapside join on a wiki/jira?

Here are some questions:

1)       Do the tables need to be sorted on "id"?

2)       Is there a restriction on the smaller table size?

Are there other join optimizations that Hive provides which I can apply
here?

 

Viraj