Re: synchronized_standby_slots behavior inconsistent with quorum-based synchronous replication

Hi,

On Sat, Apr 11, 2026 at 10:04 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Fri, Mar 20, 2026 at 2:08 PM Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> wrote:
> >
> > On Fri, Mar 20, 2026 at 1:21 PM Hou, Zhijie/侯 志杰 <houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> > >
> > > Since we're reusing the same parser for two GUCs that have different
> > > interpretations of one syntax variant (the plain slot list), making the parser
> > > more general is a natural approach, especially given that the patch is adding
> > > new functionality here.
> > >
> > > My main concern is the IsPrioritySyncStandbySlotsSyntax() function. It
> > > introduces additional hard-coded parsing logic that duplicates what's already
> > > implemented in syncrep_gram.y. I'm also concerned about maintainability,
> > > particularly since we already discovered a bug in the hard-coded parser code [1]
> > > and the patch even added a tap-test (part E) to cover that path. All of this
> > > effort could be avoided by removing this function and leveraging functionality
> > > provided by the shared parser.
> > >
> >
> > The issue that you are referring to here was without this function.
> >
> > The idea here is to reuse the existing synchronous_standby_names
> > parser as-is, without changing its grammar or parse behavior.
> > synchronized_standby_slots differs only in post-parse interpretation
> > of simple-list syntax, so we add a local helper to disambiguate
> > explicit priority mode from plain lists before applying
> > synchronized_standby_slots semantics.
> >
>
> How about splitting the patch to separate out the ANY configuration as
> the first patch? Then we can focus on the FIRST configuration
> separately and it would be easier to evaluate whether changing the
> parser for it is worth the additional complexity.
>

That sounds like a good approach. I’ll split the current patch into
two parts, with support for the ANY-based syntax being the first
patch, and share it.

--
With Regards,
Ashutosh Sharma.