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From: Magnus Hagander <magnus@hagander.net>
Date: Fri, 25 Feb 2022 17:28:41 +0100
Message-ID: <CABUevEwqqRHHZxb2tEGDNo3mhosh0ATvS0X5Gi6KEtKQKQp44w@mail.gmail.com>
Subject: Re: Add parameter jit_warn_above_fraction
To: Andres Freund <andres@anarazel.de>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
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On Fri, Feb 25, 2022 at 5:20 PM Andres Freund <andres@anarazel.de> wrote:
>
> Hi,
>
> On 2022-02-25 16:16:01 +0100, Magnus Hagander wrote:
> > This patch adds a configuration parameter jit_warn_above_fraction that
> > will cause a warning to be logged if the fraction of time spent on
> > doing JIT is bigger than the specified one. For example, this can be
> > used to track down those cases where JIT ends up taking 90% of the
> > query runtime because of bad estimates...
>
> Hm. Could it make sense to do this as a auto_explain feature?

It could be. But I was looking for something a lot more "light weight"
than having to install an extension. But yes, if we wanted to, we
could certainly change jit_warn_above_fraction to be
auto_explain.log_min_jit_fraction or something like that, and do
basically the same thing. But then, we could also have
log_min_duration_statement be part of auto_explain instead, so it's
all about where to draw the line :)

-- 
 Magnus Hagander
 Me: https://www.hagander.net/
 Work: https://www.redpill-linpro.com/