First things first, I'm asking because of idle curiosity not because of
any more pressing needs.

I know that PostgreSQL is very flexible when it comes to procedural
languages and consequently there are several implementations in addition
to PL/pgSQL. I'm wondering whether the architecture is similarly
flexible in other places. I can think of a few things that might or
might not be possible/interesting/sensible:

- Switch the SQL frontend for one with another syntax and semantics,
such as C.J. Date's Tutorial D.

- Completely exchange the query planner or amend it with specific
algorithms.

- Add another backend that stores tuples by column or some other
strategy.

These ideas are in no way meant as suggestions, but rather as
illustrations of what kind of flexibility I have in mind.

Michael

--
Michael Schuerig
mailto:michael (AT) schuerig (DOT) de
http://www.schuerig.de/michael/