> I am using the oid of the table as the main key and I've found that is
> not indexed (maybe because I have declared another primary key in the
> table)
>
> it is a good practice to create an index like this on the oid of a table?
> CREATE INDEX idoid annuncio400 USING btree (oid);
Yes it is - in fact you really should add a unique index, not just a
normal index, as you want to enforce uniqueness of the oid column. It
is theoretically possible to end up with duplicate oids in wraparound
situations.
Even better though is to not use oids at all, of course...
Chris
