Horton

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

Nathan Bossart <nathandbossart@gmail.com>

View thread View on postgr.es
From: Nathan Bossart <nathandbossart@gmail.com>
To: Ayush Vatsa <ayushvatsa1810@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, michael@paquier.xyz
Date: 2024-08-29T17:36:35Z
Lists: pgsql-hackers 
On Thu, Aug 29, 2024 at 10:17:57PM +0530, Ayush Vatsa wrote:
> Please find attached the patch that re-enables
> support for sequences within the pgstattuple extension.
> I have also included the necessary test cases for
> sequences, implemented in the form of regress tests.

Thanks.  Robert, do you have any concerns with this?

+select * from pgstattuple('serial');
+ table_len | tuple_count | tuple_len | tuple_percent | dead_tuple_count | dead_tuple_len | dead_tuple_percent | free_space | free_percent 
+-----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
+      8192 |           1 |        41 |           0.5 |                0 |              0 |                  0 |       8104 |        98.93
+(1 row)

I'm concerned that some of this might be platform-dependent and make the
test unstable.  Perhaps we should just select count(*) here.

+	/**
+	 * Sequences don't fall under heap AM but are still
+	 * allowed for obtaining tuple-level statistics.
+	 */

I think we should be a bit more descriptive here, like the comment in
verify_heapam.c:

	/*
	 * Sequences always use heap AM, but they don't show that in the catalogs.
	 * Other relkinds might be using a different AM, so check.
	 */

-- 
nathan

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.