Re: do only critical work during single-user vacuum?

On Wed, Jan 19, 2022 at 5:26 PM Michael Paquier <michael@paquier.xyz> wrote:
>
> Could you avoid introducing a new grammar pattern in VACUUM?  Any new
> option had better be within the parenthesized part as it is extensible
> at will with its set of DefElems.

This new behavior is not an option that one can sensibly mix with
other options as the user sees fit, but rather hard-codes the
parameters for its single purpose. That said, I do understand your
objection.

[*thinks*]

How about the attached patch (and test script)? It still needs polish,
but it could work. It allows "verbose" to coexist, although that's
really only for testing normal mode. While testing in single-user
mode, I was sad to find out that it not only doesn't emit messages
(not a client), but also doesn't log. That would have been a decent
way to monitor progress...

In this form, I'm no longer a fan of calling the option "wraparound",
because it's too close to the "is_wraparound" param member.
Internally, at least, we can use "emergency" or "minimal". (In fact
the bit symbol is VACOPT_MINIMAL for this draft). That can be worked
out later.

On Fri, Jan 21, 2022 at 12:59 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> The purpose of this thread is to provide a way for users to run vacuum
> only very old tables (while skipping index cleanup, etc.),

Ah, thank you Sawada-san, now I understand why we have been talking
past each other. The purpose is actually:

- to have a simple, easy to type, command
- intended for single-user mode, but not limited to it (so it's easy to test)
- to get out of single user mode as quickly as possible

--
John Naylor
EDB: http://www.enterprisedb.com