Re: Per tuple overhead, cmin, cmax, OID

Tom Lane wrote:
> Manfred Koizar <mkoi-pg(at)aon(dot)at> writes:
> > what about WITHOUT OIDS? I know dropping the OID from some tables and
> > keeping it for others is not trivial, because t_oid is the _first_
> > field of HeapTupleHeaderData. I'm vaguely considering a few possible
> > implementations and will invest more work in a detailed proposal, if
> > it's wanted.
>
> Yeah, I had been toying with the notion of treating OID like a user
> field --- ie, it'd be present in the variable-length part of the record
> if at all. It'd be a bit tricky to find all the places that would need
> to change, but I think there are not all that many.
>
> As usual, the major objection to any such change is losing the chance
> of doing pg_upgrade. But we didn't have pg_upgrade during the 7.2
> cycle either. If we put together several such changes and did them
> all at once, the benefit might be enough to overcome that complaint.

I think it is inevitable that there be enough binary file changes the
pg_upgrade will not work for 7.3 --- it just seems it is only a matter
of time.

One idea is to allow alternate page layouts using the heap page version
number, but that will be difficult/confusing in the code.

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