On Nov19, 2011, at 21:57 , Tom Lane wrote: > One thing I've been thinking for a bit is that for discrete ranges, > I find the '[)' canonical form to be surprising/confusing. If we > were to fix range_adjacent along the lines suggested by Florian, > would it be practical to go over to '[]' as the canonical form? > One good thing about that approach is that canonicalization wouldn't > have to involve generating values that might overflow.
I have argued against that in the past, mostly because 1) It's better to be consistent 2) While it seems intuitive for integer ranges to use [] and float ranges to use [), things are far less clear once you take other base types into account. For example, we'd end up making ranges over DATE use canonicalize to [], but ranges over TIMESTAMP to [). Which, at least IMHO, is quite far from intuitive. And if we start "fixing" these issues by making exception from the "discrete -> [], continuous -> [)" rule, we'll end up with essentially arbitrary behaviour pretty quickly. At which point (1) kicks it ;-) And then there also ranges over NUMERIC, which can be both discrete and continuous, depending on the typmod. Which I think is a good reason in itself to make as little behaviour as possible depend on the continuity or non-continuity of range types. best regards, Florian Pflug -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
