Re: Solving the OID-collision problem

> "Mark Woodward" <pgsql@mohawksoft.com> writes:
>>> I'm too lazy to run an experiment, but I believe it would.  Datum is
>>> involved in almost every function-call API in the backend. In
>>> particular this means that it would affect performance-critical code
>>> paths.
>
>> I hear you on the "lazy" part, but if OID becomes a structure, then you
>> are still comparing a native type until you get a match, then you make
>> one
>> more comparison to confirm it is the right one, or move on.
>
> No, you're missing the point entirely: on 32-bit architectures, passing
> a 32-bit integral type to a function is an extremely well optimized
> operation, as is returning a 32-bit integral type.  Passing or
> returning a 64-bit struct is, um, not so well optimized.

That's only if you call by value, call by reference is just as optimized.

>
> There's also the small problem that it really has to fit into Datum.
>

Would it break a lot if you add more to a datum?