Message-ID: <a5858d490737bac1696b24abbada58210e2c68eb.camel@cybertec.at>
Subject: Re: Record last SELECT on a row?
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Matthias Leisi <matthias@leisi.net>, "pgsql-generallists.postgresql.org"
	 <pgsql-general@lists.postgresql.org>
Date: Wed, 17 Dec 2025 09:41:17 +0100
In-Reply-To: <287E4DF6-35A2-4062-AEBA-32DB1DE35C5D@leisi.net>
References: <287E4DF6-35A2-4062-AEBA-32DB1DE35C5D@leisi.net>
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On Wed, 2025-12-17 at 08:40 +0100, Matthias Leisi wrote:
> An application (which we can=E2=80=99t change) is accessing some Postgres=
 table, and we would
> like to record when the rows in that table were last read (meaning: appea=
red in a
> SELECT result). The ultimate goal would be that we can =E2=80=9Eage out=
=E2=80=9C rows which have not
> been accessed in a certain period of time.
>=20
> If we had full control over the application, we could eg use a function t=
o select the
> records and then update some =E2=80=9Elast read=E2=80=9C column. But sinc=
e we don=E2=80=99t control the
> application, that=E2=80=99s not an option. On the other hand, we have ful=
l control over the
> database, so we could put some other =E2=80=9Eobject=E2=80=9C in lieu of =
the direct table.
>=20
> Any other ways this could be achieved?

I don't think that is possible.  You could log all statements, but that won=
't show
which rows are accessed.

Yours,
Laurenz Albe