Re: [v9.5] Custom Plan API

On Mon, Nov 10, 2014 at 6:33 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Mon, Nov 10, 2014 at 6:55 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
> > I thought that in general if user has the API to register the custom
path
> > methods, it should have some way to unregister them and also user might
> > need to register some different custom path methods after unregistering
> > the previous one's. I think we should see what Robert or others have to
> > say about this point before trying to provide such an API.
>
> I wouldn't bother. As KaiGai says, if you want to shut the
> functionality off, the provider itself can provide a GUC. Also, we
> really have made no effort to ensure that loadable modules can be
> safely unloaded, or hooked functions safely-unhooked.
> ExecutorRun_hook is a good example. Typical of hook installation is
> this:
>
> prev_ExecutorRun = ExecutorRun_hook;
> ExecutorRun_hook = pgss_ExecutorRun;
>

In this case, Extension takes care of register and unregister for
hook. In _PG_init(), it register the hook and _PG_fini() it
unregisters the same. So if for custom scan core pg is
providing API to register the methods, shouldn't it provide an
API to unregister the same?

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