Re: CLUSTER FREEZE

On 24 October 2013 05:58, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:

> On Thu, Oct 24, 2013 at 4:58 AM, Thomas Munro <munro(at)ip9(dot)org> wrote:
> > Hi
> > I noticed that CLUSTER doesn't have a FREEZE option. Here is a patch to
> add
> > that, for consistency with VACUUM. Is it useful?
>
> I wonder why anyone would like to freeze during CLUSTER command when
> they already have separate way (VACUUM FREEZE) to achieve it, do you
> know or can think of any case where user wants to do it along with
> Cluster command?
>

As others have said, the goal is to freeze and cluster in a single step.
You can already do that if you know how things work under the covers with:

SET vacuum_freeze_min_age = 0;
CLUSTER my_table;

This patch lets you say CLUSTER FREEZE instead. It mirrors VACUUM, which
can freeze tuples based on the GUC and tuple age or the FREEZE keyword.

> Anyway code side, I think you need to set both feeze_min_age as well
> as freeze_table_age, see VACUUM command in gram.y
>

Ok, I attach a new version that is more like VACUUM in gram.y. (Although
I'm not sure why it isn't a single boolean flag).

Thanks,
Thomas Munro