Re: Feature request - CREATE TYPE ... WITH OID = oid_number.

The reasons are simple, particularly, I don't want to bloat SQL
with CAST or ::. Its not elegant and looks ugly. If I need to bind
e.g. int or short I don't want write ::integer or ::smallint in SQL,
because I can easily map int to integer via OID...
I don't clearly understand how set_next_pg_type_oid code
can helps me.
Also I don't understand why cache of OIDs can't be used to get
results via PQexecParams in a binary form ? I can do it.
Querying the db for OIDs seems to me a good idea. But:
1. Since the structure of pg_type system catalog can be changed
the developer must be able to determine a libpq version to be able
to implement cross libpq-version of the product (especially library).
So PQversion() should be there :-)
2. To avoid memory overheads (especially in WEB environments)
it would be nice if libpq will keep cache of types metadata as a static
structure per database and provide an API to work with (in this case I
totally agree with Pavel). At least, the API should support rereading
the cache. In this case 1. (PQversion) is not needed -- libpq care it
itself :-)

2010/12/7 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>

> 2010/12/7 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> > Merlin Moncure <mmoncure(at)gmail(dot)com> writes:
> >> On Tue, Dec 7, 2010 at 11:49 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >>> Say what? He didn't say that, he said "don't assume that user-defined
> >>> types have hard-wired OIDs".
> >
> >> Well, you're right, strictly speaking. Of course, the OP is not
> >> assuming it, he is enforcing it.
> >
> > No, he's wishing he could enforce it. Which will work, mostly, until
> > the day it doesn't because of a pre-existing collision. And then he'll
> > be up the creek with a lot of software that he can't fix readily. I
> > concur with Andrew's advice: don't go there in the first place. Use a
> > cache to mitigate the costs of looking up user-defined OIDs, and you
> > won't regret it later.
> >
>
> I had to solve similar task, and probably I am not alone. Can pg
> supports some cache and some API for "custom oid"? Now, a work with
> custom types on C level is little bit unfriendly. There isn't a
> problem with builtin types - these are well defined. I agree, so
> direct access to oids for custom types isn't a good idea. But some
> general API or pattern can be nice - mainly for client side.
>
> regards
>
> Pavel
>
> > regards, tom lane
> >
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>

--
// Dmitriy.