Why is Select Count(*) slower than Select * in hive

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Happy的楠姐
Happy的楠姐 2020-12-28 16:12

When i am running queries in VirtualBox Sandbox with hive. I feel Select count(*) is too much slower than the Select *.

Can an

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  •  一个人的身影
    2020-12-28 17:04

    select * from table
    

    It can be a Map only job But

    Select Count(*) from table 
    

    It can be a Map and Reduce job

    Hope this helps.

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