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From: Alexander Korotkov <aekorotkov@gmail.com>
Date: Tue, 30 Jun 2026 22:38:00 +0300
Message-ID: 
 <CAPpHfdtaSRnD-QupnJ54WqiHm77N5HggK10zq-Ch-7+-EiW0qw@mail.gmail.com>
Subject: Re: Add SPLIT PARTITION/MERGE PARTITIONS commands
To: Pavel Borisov <pashkin.elfe@gmail.com>
Cc: Dmitry Koval <d.koval@postgrespro.ru>,
 Justin Pryzby <pryzby@telsasoft.com>,
	pgsql-hackers@lists.postgresql.org
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Hi, Pavel!

On Tue, Jun 30, 2026 at 2:25=E2=80=AFPM Pavel Borisov <pashkin.elfe@gmail.c=
om> wrote:
> On Tue, 30 Jun 2026 at 15:07, Alexander Korotkov <aekorotkov@gmail.com> w=
rote:
> > On Fri, Jun 26, 2026 at 10:50=E2=80=AFPM Alexander Korotkov
> > <aekorotkov@gmail.com> wrote:
> > > On Fri, Jun 26, 2026 at 6:20=E2=80=AFPM Dmitry Koval <d.koval@postgre=
spro.ru> wrote:
> > > > If we exclude case with DEFAULT partition, MERGE PARTITIONS command=
 was
> > > > intended to be used when an incorrect table partitioning was chosen=
.
> > > > For example, a table was initially partitioned by month, but later =
we
> > > > needed to change table partitioning by quarter. In this case, MERGE
> > > > PARTITIONS command should merge several adjacent partitions into on=
e.
> > > > Current checks are made for this case.
> > > >
> > > >  >- If there's *no* default partition, then I think the check shoul=
d be
> > > >  >relaxed; it's sufficient to verify that the bounds of the merged
> > > >  >partition do not overlap with any partition which is not being me=
rged;
> > > >
> > > > It's probably possible to do this. But in this case, the command wi=
ll
> > > > not exactly be "MERGE PARTITIONS" ("MERGE PARTITIONS & EXPAND"?).
> > >
> > > +1,
> > > We can implement a support for this for 20.  For 19, I propose to
> > > state the restriction more explicit in the docs.  See the attached
> > > patch.
> >
> > I'm going to push the docs patch if no objections.
> I looked at the doc patch. IMO "in order to be merged" is redundant.
> I'd propose following:
> "For range-partitioned tables, the ranges of merged partitions must be
> adjacent. This applies even if the partitioned table has no default
> partition."

I've included your suggestion.
Pushed and and backpatched to 19.

------
Regards,
Alexander Korotkov
Supabase