Re: [HACKERS] Block level parallel vacuum

On Tue, Oct 15, 2019 at 1:26 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Tue, Oct 15, 2019 at 4:15 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > > > > If we avoid postponing deleting empty pages till the cleanup phase,
> > > > > then we don't have the problem for gist indexes.
> > > >
> > > > Yes. But considering your pointing out I guess that there might be
> > > > other index AMs use the stats returned from bulkdelete in the similar
> > > > way to gist index (i.e. using more larger structure of which
> > > > IndexBulkDeleteResult is just the first field). If we have the same
> > > > concern the parallel vacuum still needs to deal with that as you
> > > > mentioned.
> > > >
> > >
> > > Right, apart from some functions for memory allocation/estimation and
> > > stats copy, we might need something like amcanparallelvacuum, so that
> > > index methods can have the option to not participate in parallel
> > > vacuum due to reasons similar to gist or something else.  I think we
> > > can work towards this direction as this anyway seems to be required
> > > and till we reach any conclusion for gist indexes, you can mark
> > > amcanparallelvacuum for gist indexes as false.
> >
> > Agreed. I'll create a separate patch to add this callback and change
> > parallel vacuum patch so that it checks the participation of indexes
> > and then vacuums on un-participated indexes after parallel vacuum.
>
> amcanparallelvacuum is not necessary to be a callback, it can be a
> boolean field of IndexAmRoutine.
>

Yes, it will be a boolean.  Note that for parallel-index scans, we
already have amcanparallel.

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