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https://issues.apache.org/jira/browse/SPARK-19655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15873087#comment-15873087
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Sean Owen edited comment on SPARK-19655 at 2/18/17 10:14 AM:
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What is the problem? selecting "1" _is_ an optimization, or at least, should 
make no difference at all. EDIT: I assume you mean count(1), but, if not, can 
you provide an example of which DB that affects? because of course that's not 
even an aggregate function then.


was (Author: srowen):
What is the problem? selecting "1" _is_ an optimization, or at least, should 
make no difference at all.

> select count(*) , requests 1 for each row
> -----------------------------------------
>
>                 Key: SPARK-19655
>                 URL: https://issues.apache.org/jira/browse/SPARK-19655
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 2.1.0
>            Reporter: hosein
>            Priority: Minor
>
> when I want query select count( * ) by JDBC and monitor queries in database 
> side, I see spark requests: select 1 for destination table
> it means 1 for each row and it is not optimized



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