Re: [HACKERS] Query fails when SRFs are part of FROM clause (Commitid: 69f4b9c85f)

In any case the more idiomatic way of writing your query these days (since 9.4 came out) is:

SELECT *

FROM pg_constraint pc

LEFT JOIN LATERAL generate_series(1, case when contype in ('f','p','u') then array_upper(pc.conkey, 1) else 0 end) gs ON true;