Re: maintenance_work_mem used by Vacuum

On Sat, Oct 12, 2019 at 10:49 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> On Fri, Oct 11, 2019 at 5:13 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > That's right, but OTOH, if the user specifies gin_pending_list_limit
> > as an option during Create Index with a value greater than GUC
> > gin_pending_list_limit, then also we will face the same problem. It
> > seems to me that we haven't thought enough on memory usage during Gin
> > pending list cleanup and I don't want to independently make a decision
> > to change it. So unless the original author/committer or some other
> > people who have worked in this area share their opinion, we can leave
> > it as it is and make a parallel vacuum patch adapt to it.
>
> Yeah I totally agreed.
>
> Apart from the GIN problem can we discuss whether need to change the
> current memory usage policy of parallel utility command described in
> the doc? We cannot control the memory usage in index AM after all but
> we need to generically consider how much memory is used during
> parallel vacuum.
>

Do you mean to say change the docs for a parallel vacuum patch in this
regard? If so, I think we might want to do something for
maintenance_work_mem for parallel vacuum as described in one of the
emails above [1] and then change the docs accordingly.

[1] - https://www.postgresql.org/message-id/CAA4eK1JhpNsTiHj%2BJOy3N8uCGyTBMH8xDhUEtBw8ZeCAPRGp6Q%40mail.gmail.com

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com