Re: autovacuum launcher using InitPostgres

Tom Lane wrote:
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> > Tom Lane wrote:
> >> I wonder if it would be cleaner to include the launcher in
> >> the autovacuum_max_workers parameter, and increase the min/default
> >> values of that by one.
>
> > Huh, yeah, sorry about that -- fixed here. I think the name of the
> > param, which includes "worker", precludes from raising the values.
>
> Well, I'm not sure the average user knows or cares about the difference
> between the launcher and the workers. The thing that was in the back of
> my mind was that we would now have the option to have the launcher show
> up in pg_stat_activity. If we were to do that then the case for
> counting it in the user-visible number-of-processes parameter would get
> a lot stronger (enough to justify renaming the parameter, if you insist
> that the launcher isn't a worker). I don't however have any strong
> opinion on whether we *should* include it in pg_stat_activity ---
> comments?

The user may not care about the difference, but there's a point in
having the limit be the simpler concept of "this is the maximum amount
of processes running vacuum at any time". The launcher is very
uninteresting to users.

> In the meantime, this looks reasonably sane in a fast read-through,
> but I saw a few comments that could use improvement, and I have not
> tried to actually review it (like look for missed places to change).
> Do you mind if I work it over for an hour or two?

Please go ahead.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.