On Wed, May 21, 2025 at 09:34:02AM +0900, Michael Paquier wrote: > On Tue, May 20, 2025 at 11:28:17PM +1200, David Rowley wrote: > > Certainly, a bit late, yes. It basically requires implementing > > unsigned types on the SQL level. I believe there are a few sunken > > ships along that coastline, and plenty of history in the archives if > > you want to understand some of the difficulties. > > Providing some more context and some more information than this reply, > the latest thread that I can find on the matter is this one, from > December 2024: > https://www.postgresql.org/message-id/CAN3gO4sPBKbfWYK10i294u3kzsfDb4WX891FMbjLnKjMS08u7A%40mail.gmail.com > > It summarizes nicely the situation and it contains some more general > points. > > This particular point from Tom about numeric promotion and casting > hierarchy resonates as a very good one: > https://www.postgresql.org/message-id/3180774.1733588677%40sss.pgh.pa.us > My own bet is that if you don't want to lose any existing > functionality, perhaps we should be just more aggressive with casting > requirements on input to begin with even if it means more work when > writing queries, even if it comes at a loss of usability that should > still be something..
Thanks a lot Michael! I actually read that thread at that time but forgot about it until you sent this link. > FWIW, I've wanted an unsigned in-core type more than once. It would > be a lot of work, but we have a lot of things that exist in the core > code that map to unsigned 32b or 64b integer values. Just naming one, > WAL LSN difference calculations. XLogRecPtr is a 64b unsigned value, > not its representation at SQL level, meaning that we'd overflow after > reaching the threshold of the bit tracking the signedness. It's true > that a system would need to live long enough to reach such LSNs, but > we have also 32b integers plugged here and there. Another one is > block numbers, or OID which is an in-core type. Having an in-core > unsigned integer type would scale better that creating types mapping > to every single internal core concept. Agreed.
