Re: Add MAIN_RELATION_CLEANUP and SECONDARY_RELATION_CLEANUP options to VACUUM

On Mon, 3 Aug 2020 at 15:47, Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> On Tue, Jul 14, 2020 at 05:34:01AM +0000, k(dot)jamison(at)fujitsu(dot)com wrote:
> > I've also confirmed those through regression + tap test in my own env
> > and they've passed. I'll look into deeply again if I find problems.
>
> + VACOPT_TOAST_CLEANUP = 1 << 6, /* process TOAST table, if any */
> + VACOPT_DISABLE_PAGE_SKIPPING = 1 << 7, /* don't skip any pages */
> + VACOPT_MAIN_REL_CLEANUP = 1 << 8 /* process main relation */
> } VacuumOption;
>
> Do we actually need this much complication in the option set? It is
> possible to vacuum directly a toast table by passing directly its
> relation name, with pg_toast as schema, so you can already vacuum a
> toast relation without the main part. And I would guess that users
> caring about the toast table specifically would know already how to do
> that, even if it requires a simple script and a query on pg_class.

Yeah, I also doubt we really need to have this option in the core just
for the purpose of easily specifying toast relation to VACUUM command.
If the user doesn't know how to search the toast relation, I think we
can provide a script or an SQL function executes vacuum() C function
with the toast relation fetched by using the main relation. I
personally think VACUUM option basically should be present to control
the vacuum internal behavior granularly that the user cannot control
from outside, although there are some exceptions: FREEZE and ANALYZE.

Regards,

--
Masahiko Sawada http://www.2ndQuadrant.com/
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