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From: Ron Johnson <[email protected]>
To: pgsql-general <[email protected]>
Subject: Re: Loading the latest N rows into the cache seems way too fast.
Date: Mon, 17 Feb 2025 16:40:56 -0500
Message-ID: <CANzqJaDPR_sshr1hXuMsiZQDf7nH4BthNioCHJ4cVcGKxiSg_Q@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CANzqJaBTPgTJ_M3dGiOa5H-FvAo71oCCa1QHejbzK+joKdrSyw@mail.gmail.com>
	<[email protected]>

On Mon, Feb 17, 2025 at 4:36 PM Tom Lane <[email protected]> wrote:

> Ron Johnson <[email protected]> writes:
> > The bigint "id" column in "mytbl" is populated from a sequence, and so is
> > monotonically increasing: the newest records will have the biggest id
> > values.
> > The table also has a bytea column that averages about 100KB.
>
> > Loading 200K rows is more than 200MB.  I expected this "prewarm"
> statement
> > to take much longer than 1/2 second.  Am I still in the dark ages of
> > computer speed, or is this statement not doing what I hope it's doing?
>
> It's not pulling in the TOAST storage where the bytea column lives.
> (pg_prewarm wouldn't have either, without special pushups.)
>

Puzzling, since I ran "PERFORM *".  What if I explicitly mentioned the
bytea column's name?

-- 
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!


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