> Yes, nowhere near, and yes. Sequence objects require disk I/O to
> update; the OID counter essentially lives in shared memory, and can
> be bumped for the price of a spinlock access.
Sequences also cache values (32 afair) - ie one log record is required
for 32 nextval-s. Sequence' data file is updated at checkpoint time,
so - not so much IO. I really think that using sequences for system
tables IDs would be good.
Vadim