plsqlvids01 plsqlvids01 <plsqlvids01@gmail.com> writes:
> What is the use of postgres regclass datatype in user tables? When would
> one want to use them when regular data types are available? If any tables
> have these data types, since pg_upgrade would fail, what data types should
> those be converted to?
Indeed, storing reg* types in user tables isn't particularly
recommended because of the pg_upgrade problem. However, casting
to a reg* type is plenty useful in queries on the system catalogs.
There is more info and examples in the manual:
https://www.postgresql.org/docs/current/datatype-oid.html
regards, tom lane
