It is possible that all the columns that PostgreSQL has are required by
the standard and that MariaDB is non-conforming by omitting them, but at
least some of the names look quite PostgreSQL-specific to me. So my
guess is that the standard only requires the first 4 and the rest are
RDBMS-specific.
Unless our docs are completely misleading I'd say that PostgreSQL is being conforming while MariaDB is treating information_schema as their version of pg_catalog (or at least our system views over top of pg_catalog).
If 5 and 6 and the last columns were not standard conforming it would seem pointless to include them since we don't have/implement the features they cover.
David J.
