Re: Freeze avoidance of very large table.

On Mon, Oct 5, 2015 at 9:53 PM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
wrote:
>
> On Mon, Oct 5, 2015 at 11:03 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
wrote:
> > On Fri, Oct 2, 2015 at 8:14 PM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
wrote:
> >>> +#define Anum_pg_class_relallfrozen 12
> >>> Why is pg_class.relallfrozen necessary? ISTM that there is no user of
it now.
> >>
> >> The relallfrozen would be useful for user to estimate time to vacuum
> >> freeze or anti-wrapping vacuum before being done them actually.
> >> (Also this value is used on regression test.)
> >> But this information is not used on planning like relallvisible, so it
> >> would be good to move this information to another system view like
> >> pg_stat_*_tables.
> >
> > Or make pgstattuple and pgstattuple_approx report even the number
> > of frozen tuples?
> >
>
> But we cannot know the number of frozen pages without installation of
> pageinspect module.
> I'm a bit concerned about that the all projects cannot install
> extentension module into postgresql on production environment.
> I think we need to provide such feature at least into core.
>

I think we can display information about relallfrozen it in pg_stat_*_tables
as suggested by you. It doesn't make much sense to keep it in pg_class
unless we have some usecase for the same.

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