On Wed, 2021-10-20 at 23:29 +0300, Radoslav Nedyalkov wrote: > We have a busy database that has oid increasing with 50-100M per month. > There is no oid type across user attributes anywhere nor user tables with oids; > Not sure where this generation comes from. If you can hint me, it would be great. > Also what happens when pg_class.oid reaches 4B. > pg_class itself is ~40K. Hard to say, perhaps you are creating lots of temporary tables (watch out for pg_attribute bloat!). The OID counter will simply wrap around, but there will be no duplicate OIDs in pg_class. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com