Tomas Vondra <t...@fuzzy.cz> writes: > I think that we should make the documentation more explicit about this > limitation, because the current wording in fdw-callbacks documentation > seems to suggest it's possible to add such hidden columns. At least > that's how I read it before running into this.
You can add hidden columns if you've got 'em ;-). What's missing is the ability to create any hidden columns other than the ones in standard PG tables. What we most likely need is the ability for an FDW to override the type assigned to the CTID column at foreign table creation. (We'd then also need to think about where such a column could be shoehorned into a tuple, but the catalog support has to come first.) Alternatively, it might work to append "junk" columns in the user column numbering domain, which would only exist in runtime tuple descriptors and not in the catalogs. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers