Re: [v9.3] OAT_POST_ALTER object access hooks

On Mon, Dec 3, 2012 at 9:59 AM, Kohei KaiGai <kaigai@kaigai.gr.jp> wrote:
> As we discussed before, it is hard to determine which attributes shall
> be informed to extension via object_access_hook, so the proposed
> post-alter hook (that allows to compare older and newer versions)
> works fine on 99% cases.
> However, I'm inclined to handle SET TABLESPACE as an exception
> of this scenario. For example, an idea is to define OAT_PREP_ALTER
> event additionally, but only invoked very limited cases that takes
> unignorable side-effects until system catalog updates.
> For consistency of hook, OAT_POST_ALTER event may also ought
> to be invoked just after catalog updates of pg_class->reltablespace,
> but is_internal=true.
>
> How about your opinion?

I don't really like it - I think POST should mean POST.  You can
define some other hook that gets called somewhere else, but after
means after.  There are other plausible uses of these hooks besides
sepgsql; for example, logging the completion time of an action.
Putting the hooks in the "wrong" places because that happens to be
more convenient for sepgsql is going to render them useless for any
other purpose.  Maybe nobody else will use them anyway, but I'd rather
not render it impossible before we get off the ground.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company