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From Db-Blog <>
Subject Re: largest table last in joins
Date Mon, 05 May 2014 22:44:07 GMT
If we have one big table joining with a small table and MAPJOIN hint is specified on the Smaller
table, still the ordering will be required? 

We can always forcefully set the auto convert join property to false and enable mapjoin hints.

Please let me know if I am off base on this topic. 


Sent from my iPhone, please avoid typos.

> On 05-May-2014, at 9:19 pm, Alan Gates <> wrote:
> Join ordering is not yet part of the Hive optimizer.  There is integration work being
done with the Optiq framework that will address this, but it is not complete yet.  Hopefully
at least an initial integration will be available in the next Hive release.
> Alan.
>> On May 2, 2014, at 5:36 AM, Aleksei Udatšnõi <> wrote:
>> Hello,
>> There is this old recommendation for optimizing Hive join to use the largest table
last in the join.
>> The same recommendation appears in Programming Hive book.
>> Is this recommendation still valid or newer version of Hive take care of such optimization
>> Best,
>> Aleksei
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