Re: Why hash OIDs?

On Wed, Aug 29, 2018 at 11:05 AM Thomas Munro
 wrote:
> On Wed, Aug 29, 2018 at 2:09 AM Robert Haas  wrote:
> > rhaas=# create table a (x serial primary key);
> > CREATE TABLE
> > rhaas=# create table b (x serial primary key);
> > CREATE TABLE
> > rhaas=# select 'a'::regclass::oid, 'b'::regclass::oid;
> >   oid  |  oid
> > -------+-------
> >  16422 | 16430
> > (1 row)
> >
> > If you have a lot of tables like that, bad things are going to happen
> > to your hash table.
>
> Right.  I suppose that might happen accidentally when creating a lot
> of partitions.
>
> Advance the OID generator by some prime number after every CREATE TABLE?
>
> /me ducks

Erm, s/prime/random/.   Or use a different OID generator for each
catalogue so that attributes etc don't create gaps in pg_class OIDs.

-- 
Thomas Munro
http://www.enterprisedb.com