Re: [INTERFACES] OIDs in pg_type stable across versions?

From: Guido(dot)Goldstein(at)t-online(dot)de (Guido Goldstein)
To: PG-Interfaces <pgsql-interfaces(at)postgresql(dot)org>
Subject: Re: [INTERFACES] OIDs in pg_type stable across versions?
Date: 1999-01-20 13:42:36
Message-ID: lt7lui6oxf.fsf@Guido.Goldstein.dialup.t-online.de
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Moin!

On 20 Jan 1999 11:16:31 +0100
Eric Marsden <emarsden(at)mail(dot)dotcom(dot)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

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