2010/11/18 Tom Lane <t...@sss.pgh.pa.us>: > Pavel Stehule <pavel.steh...@gmail.com> writes: >> "unnest" returns all fields, but >> these fields should not be used. There isn't possible to say - stop, I >> don't need other fields. It's possible just with special PL statement, >> because it is controlled by PL. So it is reason why I don't believe in >> optimizations on PL level. > > That is complete nonsense. array_unnest doesn't return the whole array > contents at once, so it's just as capable of being optimized as any > single-purpose implementation. If you exit the loop early, you just > don't call it anymore.
no it isn't - actually you cannot to limit a returned set when you call SRF function in expression context - if I remember well. We can change it - but this is other complexity. Pavel > > 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
