Re: The suggestion of reducing autovacuum_vacuum_cost_delay should be documented

On Tue, May 12, 2020 at 05:40:14PM -0400, Bruce Momjian wrote:
> On Tue, May 12, 2020 at 10:26:27AM +0000, PG Doc comments form wrote:
> > The following documentation comment has been logged on the website:
> >
> > Page: https://www.postgresql.org/docs/11/runtime-config-autovacuum.html
> > Description:
> >
> > The `autovacuum_vacuum_cost_delay` setting changes to 2ms in PostgreSQL 12
> > but in the old Postgresql version, the default setting is still 20ms. I
> > would suggest adding a suggestion in the old document
> > to lower the autovacuum_vacuum_cost_delay as:
> >
> > > The default value of autovacuum_vacuum_cost_delay is reduced to 2ms in
> > PostgreSQL 12. Reducing the autovacuum_vacuum_cost_delay will make the
> > autovacuum more aggressive and might reduce the vacuum cost for
> > write-intensive workload on big table.
>
> Uh, we usually don't suggest new defaults in back branches.

Basically, what I am saying is that if you want this, it would be a new
behavior that would need general discussion.