public inbox for [email protected]  

help / color / mirror / Atom feed

From: Tom Lane <[email protected]>
To: Nathan Bossart <[email protected]>
Cc: Alexander Lakhin <[email protected]>
Cc: Sami Imseih <[email protected]>
Cc: Bharath Rupireddy <[email protected]>
Cc: Robert Treat <[email protected]>
Cc: [email protected]
Cc: pgsql-hackers <[email protected]>
Cc: [email protected]
Subject: Re: Add pg_stat_autovacuum_priority
Date: Wed, 08 Apr 2026 15:21:38 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <adan_E0o69p81lIj@nathan>
References: <CAA5RZ0vxby2osMMaCuZ=680tmt583cF9n4rOzTGdsiS-1PJknA@mail.gmail.com>
	<adE9RbcA7lhH_w2d@nathan>
	<CAA5RZ0tYzPDeXbqz9uKacRV2xjD055qrg=s3w2PEQPK8EruuSg@mail.gmail.com>
	<adFiCgN22xJ7Z-oR@nathan>
	<CAA5RZ0vRP-W2wJD2OxEb-=VGj2sp5pMCqHQg9YJiuDVPhaY5jQ@mail.gmail.com>
	<adQsdvPPNviWMCXb@nathan>
	<[email protected]>
	<[email protected]>
	<adaWuTR7oCKodH7k@nathan>
	<[email protected]>
	<adan_E0o69p81lIj@nathan>

Nathan Bossart <[email protected]> writes:
> On Wed, Apr 08, 2026 at 02:53:20PM -0400, Tom Lane wrote:
>> ... Aside from this problem, the elog's that
>> relation_needs_vacanalyze emits seem 100% inappropriate and misleading
>> when it's being called from the view.

> FWIW that elog() shouldn't be emitting anything from the view, unless
> something is broken.

[ looks again... ]  Oh, you mean because pg_stat_get_autovacuum_scores
passes 0 for elevel instead of any of the valid elevel constants.
Can you say "undocumented cowboy hack"?  I'd be happier if we added
something like "#define LOG_NEVER 0  /* Never emit this message */"
to elog.h and used that.

>> 2. Add a "bool *should_free" parameter, like we have in tuplestores
>> and some other places.  It's on the caller to pfree if should_free
>> gets set, but since we'd have to touch every caller, we'd not miss
>> any.

> This sounds most similar to the "bool *may_free" idea that Andres just
> posted.  IIUC the idea is that callers can free the result if they want,
> but they aren't required to do so.

Hmm, yeah I suppose a caller that doesn't care about leakage could
skip the pfree.  But are there really any of those?  The complaint
that prompted 02502c1bc concerned databases with many many thousands
of relations.

I now realize that what you said upthread about caching the results
might be a bigger problem, ie if the pgstats code does retain all
these values then we'd have a memory bloat problem there.  Maybe
we need a more aggressive API change that includes a way to specify
"don't cache this result".

			regards, tom lane

view thread (60+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Add pg_stat_autovacuum_priority
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox