If the C code for the prior dbsize patch is not acceptable for whatever
reason, here's a SQL-based patch to replace it. It's not a drop-in for
7.3/7.4 as I'd hoped, only an 8.1 patch. I believe it is functionally
equivalent to the C patch, but simpler, shorter, and probably a tad slower.
I also removed the README section on how to aggregate since it was
incomplete/incorrect (it didn't count toasted indices) and added a SQL
function that itemizes the size for a relation's table and index data
(helpful to us in identifying bloat, measuring performance, capacity
estimation, etc).
Ed
