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To: PG-Interfaces <pgsql-interfaces@postgresql.org>
Subject: Re: [INTERFACES] OIDs in pg_type stable across versions?
References: <wzi3e56ckqo.fsf@mail.dotcom.fr>
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In-Reply-To: Eric Marsden's message of "20 Jan 1999 11:16:31 +0100"
Date: 20 Jan 1999 14:42:36 +0100
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From: Guido.Goldstein@t-online.de (Guido Goldstein)


Moin!

On 20 Jan 1999 11:16:31 +0100
	Eric Marsden <emarsden@mail.dotcom.fr> wrote:
[snipped - low level interface for scheme]
> The fe-be protocol seems to provide sufficient information to do this
> type coercion: when the backend sends the attribute data in response
> to a SELECT statement, it sends a sequence of tuples (name, type-id,
> size). The type-id is an OID from the pg_type table.
> 
> Is is reasonable to assume that these oids will be stable across
> versions and platforms, or will I have to reconstruct a table from
> a `SELECT typname, oid FROM pg_type' each time a connection is
> initiated? 

I think, yes you should. Think of user defined types! They will be
stored in pg_types also.

What you can do is: cache and share this type information between all
connections initiated from this process.  And then, from time to time,
reload the type information -- or intercept all changes on pg_type
('listen' command) and reload your type infos then.

> (or maybe there's some simpler way to do the type coercions?)

Not in my field of vision.

HAND
  Guido
-- 
In the beginning there was nothing, and then even that exploded