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From Avrilia Floratou <>
Subject Question on correlation optimizer
Date Wed, 11 Dec 2013 01:05:38 GMT

I'm running TPCH query 21 on Hive. 0.12 and have enabled
I could see the effect of the correlation optimizer on query 17 but when
running query 21 I don't actually see the optimizer being used. I used the
publicly available tpc-h queries for hive and merged all the intermediate
subqueries into one for Q21. In this query there is a correlation between
multiple subqueries since they all get lineitem as input. But what I
observe from the query plan and the execution of the query is that the
subqueries are executed one by one and their results are materialized
before the joins among them are executed. Is there any other parameter that
I need to set to make this work?


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