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From: Pavel Borisov <pashkin.elfe@gmail.com>
Date: Tue, 30 Jun 2026 15:25:31 +0400
Message-ID: 
 <CALT9ZEEuOmeJFNUviG4F+ExsVzreBV6=GPRWh-BX0rD4ejPtNA@mail.gmail.com>
Subject: Re: Add SPLIT PARTITION/MERGE PARTITIONS commands
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Dmitry Koval <d.koval@postgrespro.ru>,
 Justin Pryzby <pryzby@telsasoft.com>,
	pgsql-hackers@lists.postgresql.org
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Hi, Alexander!

On Tue, 30 Jun 2026 at 15:07, Alexander Korotkov <aekorotkov@gmail.com> wro=
te:
>
> 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@postgresp=
ro.ru> wrote:
> > > If we exclude case with DEFAULT partition, MERGE PARTITIONS command w=
as
> > > 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 one.
> > > Current checks are made for this case.
> > >
> > >  >- If there's *no* default partition, then I think the check should =
be
> > >  >relaxed; it's sufficient to verify that the bounds of the merged
> > >  >partition do not overlap with any partition which is not being merg=
ed;
> > >
> > > It's probably possible to do this. But in this case, the command will
> > > 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."

Regards,
Pavel Borisov
Supabase