Re: [PATCH] Add pg_get_tablespace_ddl() function to reconstruct CREATE TABLESPACE statement

On Tue, Nov 4, 2025 at 5:25 AM Jim Jones <jim(dot)jones(at)uni-muenster(dot)de> wrote:

> Hi Nishant
>
> On 04/11/2025 11:37, Nishant Sharma wrote:
> > Using name as parameter is more user friendly than OID.
> > Because users usually do not know the oids. Constructing
> > the DDL from the name appears better as it contains a name
> > in it. So, no gain in having an OID version of
> > pg_get_tablespace_ddl.
>
> Would you also say that having a pg_tablespace_size(oid) has no benefit?
>
> I took a look at similar functions, and the only pattern I could
> identify is that all of them take an oid parameter.
>
> pg_tablespace_size: oid and name
> pg_tablespace_location: oid
> has_tablespace_privilege: oid, name, and text
> pg_tablespace_databases: oid
> ...
> pg_get_tablespace_ddl: name
>
> I'm definitely not opposed to having just a name parameter, but I
> thought it would be worth mentioning.
>
> Best, Jim
>

Hello, Jim and Nishant!

About having an OID variant:

I definitely want to keep the current name-based parameter, and it looks
like we all agree on that.

The question is if we should additionally have an OID-based variant.

I personally see no harm in additionally having an OID-based variant,
seeing as it looks like a lot of functions do seem to take an OID. If I
understand correctly, many functions take an OID, and Postgres users are
supposed to have read the docs (
https://www.postgresql.org/docs/current/datatype-oid.html) to know to cast
names to OIDs. So, in terms of following established practice / patterns,
an OID-based variant is defensible.

Thankfully for people like me (for whom the "just cast the OID to a name"
pattern never sunk in after 25 years of using Postgres), I'm glad text/name
variants of functions are also a thing in Postgres, as I suspect every time
a user has a choice between the two, a user will choose to just provide the
name.

Let me know what you think!

Thanks, Jim,

Thanks Nishant for fixing/improving my v2 patch to v3!

-Manni