Re: should vacuum's first heap pass be read-only?

On Thu, Mar 31, 2022 at 6:43 PM Peter Geoghegan <pg@bowt.ie> wrote:
> > The only way the conveyor belt system has any
> > value is if we think that there is some set of circumstances where the
> > heap scan is separated in time from the index vacuum, such that we
> > might sometimes do an index vacuum without having done a heap scan
> > just before.
>
> I agree.

But in http://postgr.es/m/CA+Tgmoa6kVEeurtyeOi3a+rA2XuynwQmJ_s-h4kUn6-bKMMDRw@mail.gmail.com
(and the messages just before and just after it) we seemed to be
agreeing on a design where that's exactly what happens. It seemed like
a good idea to me at the time, but now it seems like it's a bad idea,
because it involves using the conveyor belt in a way that adds no
value.

Am I confused here?

-- 
Robert Haas
EDB: http://www.enterprisedb.com