OID Perfomance - Object-Relational databases

Folks,
Because it's a very elegant solution to my database structure issues,
I'm using OID's extensively as referents and foriegn keys.  However, I
wanted to see if others had previous experience in this (answer as many
as you like):

1. Is there a performance loss on searches and joins when I use the OID
as a liniking field as opposed to a SERIAL column?

2. Can I define my own index on the OIDs of a table?

3. What is the difference between these two DDL statements in terms of
data access and PG-SQL performance (assuming that table clients has
already been defined):

CREATE TABLE client_addresses AS (client_OID    OID    REFERENCES clients,address1    VARCHAR (30),address2    VARCHAR
(30),address3   VARCHAR (30))
 
and:
CREATE TABLE client_addresses AS (client        clients,address1    VARCHAR (30),address2    VARCHAR (30),address3
VARCHAR(30))
 

(This is Michael's questions rephrased)

4. Int4 seems kinda small to me for a value that needs to enumerate
every single database object.  Within a couple of years of heavy use, a
customer-transaction database could easily exceed 2 billion objects
created (and destroyed).  Are there plans to expand this to Int8?

-Josh Berkus

P.S. My aplolgies if I've already posted these questions; I never
received them back from the list mailer.


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