Ok, so MVCC is the best thing since a guy put a round stone on a stick and called it "the wheel", but I've seen several references on this list about "indexes not being under MVCC" - at least that's how I read it, the original posts were explaining why indexes can't be used for solving MIN()/MAX()/COUNT() aggregates. Is this correct? In particular, I'm trying to find out is there (b)locking involved when concurrently updating and/or inserting records in an indexed table. My guess is that, since PG does copy+delete on updating, even updating a non-indexed field will require fixups in the index tree (to point to the new record) and thus (b)locking.
