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Re: Adding percentile metrics to pg_stat_statements module - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: Adding percentile metrics to pg_stat_statements module
Date
Msg-id 20191101141751.6ixckomofyhejqws@development
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In response to Re: Adding percentile metrics to pg_stat_statements module  (Igor Calabria <igor.calabria@gmail.com>)
Responses Re: Adding percentile metrics to pg_stat_statements module  (Igor Calabria <igor.calabria@gmail.com>)
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On Fri, Nov 01, 2019 at 11:11:13AM -0300, Igor Calabria wrote:
>Yeah, I agree that there's no reason to store the digests themselves and I
>really liked the idea of it being optional.

That's not what I wrote. My point was that we *should* store the digests
themselves, otherwise we just introduce additional errors into the
estimates, because it discards the weights/frequencies.

>If it turns out that memory consumption on real workloads is small enough,
>it could eventually be turned on by default.
>

Maybe, but it's not just about memory consumption. CPU matters too.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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