Re: Fix publisher-side sequence permission reporting

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Tristan Partin <tristan@partin.io>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-07-02T09:55:13Z
Lists: pgsql-hackers

Attachments

On Wed, Jul 1, 2026 at 9:38 PM Fujii Masao <masao.fujii@gmail.com> wrote:
>
> On Wed, Jun 24, 2026 at 2:40 PM Bharath Rupireddy
> <bharath.rupireddyforpostgres@gmail.com> wrote:
> >
> > Hi,
> >
> > On Tue, Jun 23, 2026 at 5:41 PM Fujii Masao <masao.fujii@gmail.com> wrote:
> > >
> > > BTW, isn't the current documentation a bit misleading? It says:
> > >
> > >     This function returns a row of NULL values if the sequence does not exist.
> > >
> > > But if the specified object does not exist, pg_get_sequence_data()
> > > raises an error rather than returning a row of NULL values. On the
> > > other hand, it does return a row of NULL values if the specified
> > > object exists but is not a sequence. Is my understanding correct? If
> > > so, how about something like:
> >
> > When the provided relation oid doesn't exist, returns NULL:
> > postgres=# select pg_get_sequence_data(99999999);
> >  pg_get_sequence_data
> > ----------------------
> >  (,,)
> > (1 row)
>
> Yes. If the specified OID does not exist, the function returns a row of
> NULL values. However, if the object is specified by name and it does
> not exist, an error is raised because the argument has type regclass.
>
> That's why I find the current wording "This function returns a row of
> NULL values if the sequence does not exist." a bit misleading.
>
> How about something like this instead?
>
>     This function returns a row of NULL values if the specified relation
>     OID does not exist, if it is not a sequence, if the current user lacks
>     <literal>SELECT</literal> privilege on the sequence, if the sequence
>     is another session's temporary sequence, or if it is an unlogged
>     sequence on a standby server.
>

Sounds reasonable. But after this we don't need the next para to say:
"It requires <literal>SELECT</literal> privilege on the sequence.".
See attached.

>
> > > The attached patch adds those HINT messages. It also updates the
> > > related documentation.
> >
> > Nice! This looks more explicit and clarifying. The patch LGTM.
>
> Thanks for the review!
>
> I've updated the patch furthermore. Attached.
>

LGTM.

-- 
With Regards,
Amit Kapila.

Commits

  1. Fix unlogged sequence corruption after standby promotion

  2. doc: Clarify pg_get_sequence_data() privileges and NULL results

  3. Fix misreporting of publisher sequence permissions during sync

  4. Introduce pg_sequence_read_tuple().