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Re: Fix incorrect start up costs for WindowAgg paths (bug #17862) - Mailing list pgsql-hackers

From Andy Fan
Subject Re: Fix incorrect start up costs for WindowAgg paths (bug #17862)
Date
Msg-id CAKU4AWqDHY6KYcuKuRTpWngvgtT7aGPSZCYWjYHZv2m4CQwsNA@mail.gmail.com
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In response to Fix incorrect start up costs for WindowAgg paths (bug #17862)  (David Rowley <dgrowleyml@gmail.com>)
Responses Re: Fix incorrect start up costs for WindowAgg paths (bug #17862)  (David Rowley <dgrowleyml@gmail.com>)
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On Wed, Apr 12, 2023 at 5:04 PM David Rowley <dgrowleyml@gmail.com> wrote:

With the attached patch, that turns into:

The concept of startup_tuples for a WindowAgg looks good to me, but I 
can't follow up with the below line:

+ return clamp_row_est(partition_tuples * DEFAULT_INEQ_SEL);

# select count(*) over() from tenk1 limit 1;
 count
-------
 10000  -->  We need to scan all the tuples.  

Should we just return clamp_row_est(partition_tuples)? 
 

--
Best Regards
Andy Fan

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