public inbox for [email protected]  

help / color / mirror / Atom feed

From: Yugo Nagata <[email protected]>
To: Dean Rasheed <[email protected]>
Cc: SATYANARAYANA NARLAPURAM <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Infinite Autovacuum loop caused by failing virtual generated column expression
Date: Tue, 14 Apr 2026 15:24:25 +0900
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAEZATCXWgYexeVm8yS6G8oFyyF=8ef9QwDt4Eyia-5hxBhjoVw@mail.gmail.com>
References: <CAHg+QDcdkGQ4Q683Uq7ZJ0P6NcbB=F3Sh8thMSiFY9wwnSEoQQ@mail.gmail.com>
	<CAEZATCXWgYexeVm8yS6G8oFyyF=8ef9QwDt4Eyia-5hxBhjoVw@mail.gmail.com>

On Sat, 11 Apr 2026 17:33:13 +0100
Dean Rasheed <[email protected]> wrote:

> On Fri, 10 Apr 2026 at 21:19, SATYANARAYANA NARLAPURAM
> <[email protected]> wrote:
> >
> > PG19 added support for stats on virtual generated columns [1]. Creating extended statistics on a virtual generated column whose expression can raise an error leads to ANALYZE failing repeatedly, and autovacuum retrying indefinitely. This floods the server logs and also wastes resources. Vacuum analyze on that column (without extended stats) succeeds.
> >
> 
> True, though this is nothing new. The same thing can happen with
> expression statistics on an expression that raises an error, which has
> been possible since PG14.

Yes, this issue is not new, and I’m not aware of a way to prevent it a priori.

> 
> > In order to avoid retry storms, I think we have two options. (1) skipping the offending row from the sample, (2) skipping the extended stats computation for that table with a warning message. At least this avoid autovacuum infinite retry. Attached a draft patch for the option (2). Thoughts?
> >
> 
> I'm not sure. The default retry interval is 1 minute, so it won't
> exactly be a flood of messages. Also, if the error only occurs for a
> small subset of rows, it's possible that retrying might succeed.

I think it would be good to skip ANALYZE for the extended statistics that cause
errors and just emit a warning, rather than aborting ANALYZE for the entire table.
It seems reasonable to treat this as the user’s responsibility to notice the warning
and address the underlying issue.

Regards,
Yugo Nagata

-- 
Yugo Nagata <[email protected]>

view thread (7+ 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]
  Subject: Re: Infinite Autovacuum loop caused by failing virtual generated column expression
  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