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Hive Functions slow too much my query

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New Contributor

Hello  I'm new to the community and to cloudera/big data in general, 

 

I am having issues with hive performance I have for example a table of 600 records and when I use a select * it runs in .05 seconds but if I use for example a count(*) or any function it runs in like 17 seconds, do any have any tip or trick to check performance or what parameter to check/modify in order to improve this execution time?

 

My enviroment are CDH 6.1.0 withHive 2.1.1-cdh6.1.0

 

Thank you in advance 

 

Ulises Rangel

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4 REPLIES 4

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Hi Ulises,

 

This is expected.

 

When you do select *  without any complex aggregation / function hive can directly read the data from hdfs / files

 

But in case of count it need to do computation which involve creating job and doing the required aggregation which will take time.

 

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New Contributor

Thanks for the reply 

 

I know is a normal thing to happend but is there anything I could check in order to know if there is something wrong with my configuration?  or maybe a job trace, I am a newbie in this topics

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New Contributor

Thanks  I will start from there