Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

On Mon, Jun 22, 2026 at 1:44 PM Pavel Borisov <pashkin(dot)elfe(at)gmail(dot)com> wrote:
> On Sun, 21 Jun 2026 at 16:11, Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
> >
> > On Thu, Jun 18, 2026 at 6:49 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
> > > On Thu, Jun 18, 2026 at 10:31:11AM +0300, Alexander Korotkov wrote:
> > > > Pushed with your suggestions accepted.
> > >
> > > Thanks. When I went back to test this, I merged ~25 partitions that
> > > were all on the same tablespace, but the merged table was created on the
> > > default tablespace.
> > >
> > > I tried again with default_tablespace set, but it was ignored. I think
> > > that's wrong. It's good to follow the tablespace of the parent table,
> > > but if it has no tablespace set, default_tablespace should be obeyed.
> > > See surrounding logic in DefineRelation.
> > >
> > > I see the docs say this:
> > > + <command>ALTER TABLE MERGE PARTITION</command> uses the partitioned
> > > + table itself as the template to construct the new partition.
> > > + The new partition will inherit the same table access method, persistence
> > > + type, and tablespace as the partitioned table.
> >
> > Correct, please see the attached patch, it makes
> > createPartitionTable() deal with tablespaces the same was as
> > DefineRelation() does.
>
> Thank you for working on this feature!
> I've looked into the last v1 patch.
>
> Does it also worth inheriting DefineRelation()'s check and error for
> the case if (tablespaceId == GLOBALTABLESPACE_OID)?
> A brief look for default_tablespace GUC doesn't reveal a way why it
> could not be set to global tablespace in a session.

Thank you for catching this. I've added this check and corresponding tests.

------
Regards,
Alexander Korotkov
Supabase