Dear Vijay
Many thanks for the comprehensive response.
The installed Postgres is just the current standard Ubuntu 22.04 LTS
release. The output of pg_config is below. Since the reboot we've not had
the error again (even though I'm still getting concurrency issues) and
having reached out to Linode
My bad. I was expecting primary and unique to be mentioned here, so I did not
read on.
**INCLUDING CONSTRAINTS***
**#[https://www.postgresql.org/docs/current/sql-createtable.html#SQL-CREATETABLE-PARMS-LIKE-OPT-CONSTRAINTS]*
/*CHECK*// constraints will be copied. No distinction is made between
