From: Bruce Momjian <bruce@momjian.us>
To: Dave Page <dpage@pgadmin.org>
Cc: David Rowley <dgrowleyml@gmail.com>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Tracking last scan time
Date: Wed, 31 Aug 2022 12:13:37 -0400
Message-ID: <Yw+IsSDlUhbjFiZO@momjian.us> (raw)
In-Reply-To: <CA+OCxoyW+T=xUdehU=oDcHeK-qw7ToaSvy0aOpbdWAa4Q_iL4w@mail.gmail.com>
References: <CA+OCxozrVHNFVEPkweUHMZje+t1tfY816d9MZYc6eZwOOusOaQ@mail.gmail.com>
<YwYzLM0vXFHRbogY@momjian.us>
<CA+OCxoxFFLz+nQteim-Fx=2_eFx0hj2AY8PKwEbE11Y0KRBPug@mail.gmail.com>
<YwY90ApeDiNjzhH4@momjian.us>
<CAApHDvpDVYKSzJ0n3ho7fbGCpK-_q--DndG7X9W0MHjF0Q6OXg@mail.gmail.com>
<CA+OCxozMPTZjLaiYOvBzFEp-pTKnPOTQ7vckEs+MbVyf=HRchg@mail.gmail.com>
<Yw5a/xZk/OXC/c+l@momjian.us>
<CA+OCxoyW+T=xUdehU=oDcHeK-qw7ToaSvy0aOpbdWAa4Q_iL4w@mail.gmail.com>
On Wed, Aug 31, 2022 at 05:02:33PM +0100, Dave Page wrote:
>
>
> On Tue, 30 Aug 2022 at 19:46, Bruce Momjian <bruce@momjian.us> wrote:
>
> On Fri, Aug 26, 2022 at 02:05:36PM +0100, Dave Page wrote:
> > On Thu, 25 Aug 2022 at 01:44, David Rowley <dgrowleyml@gmail.com> wrote:
> > I don't have a particular opinion about the patch, I'm just pointing
> > out that there are other ways. Even just writing down the numbers on
> a
> > post-it note and coming back in a month to see if they've changed is
> > enough to tell if the table or index has been used.
> >
> >
> > There are usually other ways to perform monitoring tasks, but there is
> > something to be said for the convenience of having functionality built in
> and
> > not having to rely on tools, scripts, or post-it notes :-)
>
> Should we consider using something cheaper like time() so we don't need
> a GUC to enable this?
>
>
> Interesting idea, but on my mac at least, 100,000,000 gettimeofday() calls
> takes about 2 seconds, whilst 100,000,000 time() calls takes 14(!) seconds.
Wow. I was just thinking you need second-level accuracy, which must be
cheap somewhere.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Indecision is a decision. Inaction is an action. Mark Batterson
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To: pgsql-hackers@postgresql.org
Cc: bruce@momjian.us, dpage@pgadmin.org, dgrowleyml@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Tracking last scan time
In-Reply-To: <Yw+IsSDlUhbjFiZO@momjian.us>
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