From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Nisha Moond <nisha.moond412@gmail.com>
To: Gunnar Morling <gunnar.morling@googlemail.com>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: Unexpected behavior when setting "idle_replication_slot_timeout"
Date: Fri, 04 Jul 2025 18:07:29 +0200
Message-ID: <686577f2379e4b978803e72746dcf0dd7baf3937.camel@cybertec.at> (raw)
In-Reply-To: <b26f13d7-769a-4b64-8bed-cb3a833c0604@oss.nttdata.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>
On Sat, 2025-07-05 at 00:22 +0900, Fujii Masao wrote:
> On 2025/07/04 23:12, Fujii Masao wrote:
> > But I wonder why the current unit of this GUC is minutes (GUC_UNIT_MIN).
> > Since at least two users (including myself) tried to set it to a value
> > less than 1 minute, it might worth considering changing the unit to seconds
> > (GUC_UNIT_S). Also which would reduces the chance of the reported trouble.
>
> Attached patch changes unit of idle_replication_slot_timeout to seconds.
-1
I think that the reason that several users tried to set it it less than a minute
is that they were trying to test the feature and didn't want to wait long.
I cannot imagine that anybody will want to abandon a standby server just
because it is idle for more than 30 seconds.
For me, there would be two appealing alternatives:
1. Always round up to the next minute.
2. Use the value -1 to deactivate the feature.
Optionally, we could forbid the value 0 in this case.
Stepping back a bit, I am not happy with the documentation. I looked at it,
trying to figure out what the parameter does, and I am none the wiser.
What exactly does it mean for a replication slot to idle?
- Does it mean that the standby is not connected?
- Does it mean that the standby is connected, but gives no feedback?
Probably not, but I only guess that because I know that there is a different
parameter for that.
- Does it mean that the standby is giving feedback, but that feedback doesn't
indicate progress?
I think we could do better here.
Yours,
Laurenz Albe
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To: pgsql-bugs@postgresql.org
Cc: laurenz.albe@cybertec.at, 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: <686577f2379e4b978803e72746dcf0dd7baf3937.camel@cybertec.at>
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