Re: Identifying user-created objects

On Thu, 13 Feb 2020 at 17:13, Julien Rouhaud  wrote:
>
> On Thu, Feb 13, 2020 at 8:32 AM Amit Langote  wrote:
> >
> > On Thu, Feb 13, 2020 at 10:30 AM Kyotaro Horiguchi
> >  wrote:
> > > At Mon, 10 Feb 2020 14:32:44 +0900, Amit Langote  wrote in
> > > > Agree that ObjectIsUserObject(oid) is easier to read than oid >=
> > > > FirstNormalObject.  I would have not bothered, for example, if it was
> > > > something like oid >= FirstUserObjectId to begin with.
> > >
> > > Aside from the naming, I'm not sure it's sensible to use
> > > FirstNormalObjectId since I don't see a clear definition or required
> > > characteristics for "user created objects" is.  If we did CREATE
> > > TABLE, FUNCTION or maybe any objects during single-user mode before
> > > the first object is created during normal multiuser operation, the
> > > "user-created(or not?)" object has an OID less than
> > > FirstNormalObjectId. If such objects are the "user created object", we
> > > need FirstUserObjectId defferent from FirstNormalObjectId.
> >
> > Interesting observation.  Connecting to database in --single mode,
> > whether done using initdb or directly, is always considered
> > "bootstrapping", so the OIDs from the bootstrapping range are
> > consumed.
> >
> > $ postgres --single -D pgdata postgres
> >
> > PostgreSQL stand-alone backend 13devel
> > backend> create table a (a int);
> > backend> select 'a'::regclass::oid;
> >          1: oid (typeid = 26, len = 4, typmod = -1, byval = t)
> >         ----
> >          1: oid = "14168"       (typeid = 26, len = 4, typmod = -1, byval = t)
> >
> > Here, FirstBootstrapObjectId < 14168 < FirstNormalObjectId
>
> FTR it's also possible to get the same result using binary mode and
> binary_upgrade_set_next_XXX functions.
>
> > Maybe we could document that pg_is_user_object() and its internal
> > counterpart returns true only for objects that are created during
> > "normal" multi-user database operation.
>
> +1

Agreed.

Attached updated version patch.

Regards,

-- 
Masahiko Sawada            http://www.2ndQuadrant.com/
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