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>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Nisha Moond <nisha.moond412@gmail.com>
Cc: Gunnar Morling <gunnar.morling@googlemail.com>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: Unexpected behavior when setting "idle_replication_slot_timeout"
Date: Sat, 05 Jul 2025 10:47:56 +0200
Message-ID: <bf246a31f989357a1e4eb39e68d6bc078b394bf3.camel@cybertec.at> (raw)
In-Reply-To: <CAKFQuwbUEOww3_1h_aBnQDWdc1xz5egrP9iE_b_whb2cv3pLLQ@mail.gmail.com>
References: <CADGJaX_0+FTguWpNSpgVWYQP_7MhoO0D8=cp4XozSQgaZ40Odw@mail.gmail.com>
<CABdArM76e8-XChodqKxEiRK3tR_Yv3cymn_AWfP4bOsLDscZAg@mail.gmail.com>
<30e91649-06dd-453e-8658-5f4acd03a3bd@oss.nttdata.com>
<b26f13d7-769a-4b64-8bed-cb3a833c0604@oss.nttdata.com>
<686577f2379e4b978803e72746dcf0dd7baf3937.camel@cybertec.at>
<CAA4eK1Lp+ZY2Mr3jtspF_oKDUx7241h_Ke7g5g+D-XHFA7xC+g@mail.gmail.com>
<3422d282fd45e460b4ce1bd0745523ba63bd3848.camel@cybertec.at>
<CAKFQuwbUEOww3_1h_aBnQDWdc1xz5egrP9iE_b_whb2cv3pLLQ@mail.gmail.com>
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 rounding
> to integer occurs after any unit conversion.") and not in every
> time-related setting that chooses to use something larger than microseconds.
> 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 is 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.
> As-is, the description
> matches the name and the callout to the field in the second paragraph
> precisely clears up what this setting at least cares about. The reader
> should be directed to how that field is computed should they need clarification.
>
> Thus, I'd accept but not find required the idle/inactive wording change to
> 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%3DC9SO3Q93NgVDgbKN7LQ%40mail.gmail.com
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To: pgsql-bugs@postgresql.org
Cc: laurenz.albe@cybertec.at, david.g.johnston@gmail.com, amit.kapila16@gmail.com, masao.fujii@oss.nttdata.com, nisha.moond412@gmail.com, gunnar.morling@googlemail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: Unexpected behavior when setting "idle_replication_slot_timeout"
In-Reply-To: <bf246a31f989357a1e4eb39e68d6bc078b394bf3.camel@cybertec.at>
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