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From Thejas Nair <thejas.n...@gmail.com>
Subject Re: Issue with Star schema
Date Wed, 16 Mar 2016 01:06:35 GMT
As suggested, looking at the explain plan should tell you if map-join
is getting used.
Using a recent version with hive-on-tez would also give you further
speedup as map-joins are optimized further in it.


On Tue, Mar 15, 2016 at 9:32 AM, sreebalineni . <sreebalineni@gmail.com> wrote:
> You can think of map joins.If cluster is configured by default it must be
> happening already check query profile
>
> On Tue, 15 Mar 2016 21:12 Himabindu sanka, <himabindu.sanka@gmail.com>
> wrote:
>
>> Hi Team,
>>
>>
>>
>> I have a query where I am joining with 10 other entities
>>
>>
>>
>> Like
>>
>>
>>
>> Select  a.col1,b1.col1,b2.col1 from
>>
>>
>>
>> A a
>>
>> Left outer join b1 on
>>
>> Left outer join b2 on
>>
>> Left outer join b3….
>>
>>
>>
>>
>>
>> A is my driver entity which a 20 million data. Most of the other entities
>> are small just 10 to 20 rows of data.
>>
>>
>> In that scenario, my hive query is taking hours of time to join and fetch
>> it.  Please suggest me optimization technique.
>>
>> This is chocking the query performance.
>>
>>
>>
>>
>>
>> *Regards,*
>>
>> *Himabindu Sanka*
>>

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