Horton

Re: Pgstattuple on Sequences: Seeking Community Feedback on Potential Patch

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Ayush Vatsa <ayushvatsa1810@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2024-09-01T23:44:49Z
Lists: pgsql-hackers 
On Fri, Aug 30, 2024 at 04:06:03PM -0500, Nathan Bossart wrote:
> I suppose it would be difficult to argue that it is actually useful, given
> it hasn't worked since v11 and apparently nobody noticed until recently.
> If we're content to leave it unsupported, then sure, let's just remove the
> "relkind == RELKIND_SEQUENCE" check in pgstat_relation().  But I also don't
> have a great reason to _not_ support it.  It used to work (which appears to
> have been intentional, based on the code), it was unintentionally broken,
> and it'd work again with a ~1 line change.  "SELECT count(*) FROM
> my_sequence" probably doesn't provide a lot of value, but I have no
> intention of proposing a patch that removes support for that.

IMO, it can be useful to check the state of the page used by a
sequence.  We have a few tweaks in sequence.c like manipulations of
t_infomask, and I can be good to check for its status on corrupted
systems.
--
Michael

Commits

  1. Fix contrib/pageinspect's test for sequences.

  2. Reintroduce support for sequences in pgstattuple and pageinspect.

  3. Only allow heap in a number of contrib modules.