Message-ID: <91687275-3826-49fc-b705-70ab2b6e0bcf@joeconway.com>
Date: Wed, 17 Dec 2025 11:46:14 -0500
MIME-Version: 1.0
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Subject: Re: Record last SELECT on a row?
To: Matthias Leisi <matthias@leisi.net>,
 pgsql-general <pgsql-general@postgresql.org>
References: <287E4DF6-35A2-4062-AEBA-32DB1DE35C5D@leisi.net>
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 <E680D170-8CDB-47B6-9354-2DF8FF7CB1ED@leisi.net>
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From: Joe Conway <mail@joeconway.com>
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On 12/17/25 11:25, Matthias Leisi wrote:
> 
>> pgaudit might satisfy your needs, since it would only log SELECT 
>> statements on that one table.  You'd still have to grep the log file, 
>> so the information wouldn't be real-time, but that's /probably/ not 
>> important.
> 
> That’s a viable suggestion, thanks a lot. Real-time is indeed not 
> necessary, a daily (or even a weekly) cleaning of unused data is 
> sufficient. pgaudit was anyway on the table for some other use cases, so 
> that would fit in nicely.

Possibly try using/abusing RLS?

8<-----------------
psql test
psql (19devel)
Type "help" for help.

create table t1(c1 int, c2 text);
insert into t1 values(1,'a'),(2,'b'),(3,'c'),(42,'zp');
grant select on table t1 to public;

create table a1(c1 int, t1 timestamptz);
create or replace function audit(int)
returns bool as
$$
   insert into a1 values($1, now()) returning true
$$ security definer language sql;
create policy audit_t1 ON t1 for select using (audit(c1));
alter table t1 enable row level security;

create user joe;
set session authorization joe;
select * from t1 where c1=42;

  c1 | c2
----+----
  42 | zp
(1 row)

reset session authorization;
select * from a1;

  c1 |              t1
----+-------------------------------
  42 | 2025-12-17 11:42:51.871843-05
(1 row)
8<-----------------

HTH,

-- 
Joe Conway
PostgreSQL Contributors Team
Amazon Web Services: https://aws.amazon.com