2. Is there any performance or other advantage to using PL/pgsql over Pl/Perl or Python?
Yes, if you want to loop over large amounts of data (FOR row IN SELECT) plpgsql will be faster since it does not have to convert the data from postgres to python/perl format.
---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq