This doesn't free me from adding a TO_CHAR to every timestamp column which is cumbersome if you have to replace every "select * …" with an explicit list of all columns.

True, but at the moment I don't know enough about Pg to suggest any better solutions than the ones I already have. As for the Perl solution, note it's possible to detect date/time columns by inspecting $sth->{pg_type} (in my code I use a regex like /^(?:datetime|timestamp(?:tz)?)$/i). For other database typesdrivers it's $sth->{TYPE} (I don't think this is standardized). And a comment in terms of future-proofing the code, SELECT * only makes sense to me if you're using selectrow_hashref or one of its variants, and otherwise, using query builders is useful too; Mojo::Pg provdes easy access to SQL::Abstract.