Simon, The University of North Carolina (I think?) did some nice work on not only hypothetical indexes, but hypothetical materialized views (as well as really materialized view planner selection). Have you looked at that work? I think I forwarded the paper & code to Jonah at one point ...
-- --Josh Josh Berkus PostgreSQL @ Sun San Francisco ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq