Support the system column xmin in pg_catalog.pg_namespace

[neverchanje]

The datagrip query:

select N.oid::bigint as id,
       N.xmin as state_number,
       nspname as name,
       D.description,
       pg_catalog.pg_get_userbyid(N.nspowner) as "owner"
from pg_catalog.pg_namespace N
  left join pg_catalog.pg_description D on N.oid = D.objoid

The minimal reproducible query:

select N.xmin as state_number
from pg_catalog.pg_namespace N;

[neverchanje]

#12021 duplicated