"Marc G. Fournier" <scrappy(at)postgresql(dot)org> writes:
> I'm still loading the 'WITHOUT OIDS' database ... should I expect that,
> with CLUSTERing, its performance would be slightly better yet, or would
> the difference be negligible?
I think the difference will be marginal, but worth doing; you're
reducing the row size from 40 bytes to 36 if I counted correctly,
so circa-10% I/O saving, no?
24 bytes minimum 7.4 HeapTupleHeader
4 bytes OID
12 bytes three int4 fields
On a machine with 8-byte MAXALIGN, this would not help, but on
Intel hardware it should.
regards, tom lane