Message-ID: <bf246a31f989357a1e4eb39e68d6bc078b394bf3.camel@cybertec.at>
Subject: Re: Unexpected behavior when setting "idle_replication_slot_timeout"
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: smithpb2250@gmail.com, Amit Kapila <amit.kapila16@gmail.com>, Fujii
 Masao	 <masao.fujii@oss.nttdata.com>, Nisha Moond
 <nisha.moond412@gmail.com>,  Gunnar Morling
 <gunnar.morling@googlemail.com>, pgsql-bugs@lists.postgresql.org
Date: Sat, 05 Jul 2025 10:47:56 +0200
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On Fri, 2025-07-04 at 23:16 -0700, David G. Johnston wrote:
> We should clearly document how rounding works in section 19.1.1
> (which we mostly do; "If the parameter is of integer type, a final roundi=
ng
> to integer occurs after any unit conversion.") and not in every
> time-related setting that chooses to use something larger than microsecon=
ds.
> So, 30s is 'unit converted' up to 0.5 minutes (not explicitly explained..=
.)
> then rounded to zero (which is odd, half normally rounds up...).
> I'm against cluttering up the individual settings docs with this detail.

That's fine with me; do you have a patch?

> If the change from idle to inactive=C2=A0is needed in the description we =
should
> just admit we named it wrong in the first place.

I had half a mind to propose renaming the parameter, but I shied from
a lengthy bikeshedding discussion.  Reading up on the archives, I see
that Peter Smith proposed the term "idle" in [1], and nobody had any
problem with it.

For the record: I would be much more happy if the parameter were called
"inactive_replication_slot_timeout", since we use the term "active" in
"pg_replication_slots".  Also, we call connections "idle" when they are
established, but doing nothing, and this parameter is about disconnected
replication connections.

>                                                 =C2=A0 As-is, the descrip=
tion
> matches the name and the callout to the field in the second paragraph
> precisely clears up what this setting at least cares about.=C2=A0 The rea=
der
> should be directed to how that field is computed should they need clarifi=
cation.
>=20
> Thus, I'd accept but not find required the idle/inactive wording change t=
o
> any of various degrees; and would ask that any clarification regarding
> generic setting value interpretation be relegated to 19.1.1 where all
> such settings can benefit.

I am sure that there is some information in these sentences, but I cannot
extract it, even after reading them twice.

Yours,
Laurenz Albe

 [1]: https://postgr.es/m/CAHut%2BPtHbYNxPvtMfs7jARbsVcFXL1%3DC9SO3Q93NgVDg=
bKN7LQ%40mail.gmail.com