On Mon, Oct 25, 2010 at 2:27 PM, Jeff Davis <pg...@j-davis.com> wrote: > On Mon, 2010-10-25 at 13:00 -0400, Robert Haas wrote: >> I'm still confused. It seems to me (and maybe I'm full of it) that >> the distinction between continuous ranges and discrete ranges is >> pretty minor. Suppose you have continuous ranges done, and working. >> The only thing you need to add for discrete ranges (I think) is a >> canonicalization function that converts a range with one or both ends >> open to a range with both ends closed. Then you just apply this >> canonicalization functions to every value supplied by the user before >> doing anything else with it. Poof, discrete ranges! What am I >> missing? > > That's not too far from what I'm suggesting. On the wiki page, under > "approach 2" you'll see that one of the functions needed is a > "constructor" which would put it into a canonical form (if applicable) > and construct the representation. > > I think the difference is that I assumed that the UDFs used for the type > definition would handle both canonicalization and representation. I > think what you're suggesting is that postgres could handle > representation, and just always call the UDF to put it in canonical form > first. That might make it easier to define new types, but might limit > any representation optimizations that certain range types may be able to > exploit. Either approach seems reasonable to me.
<reads wiki page> Hmm. Do you have some concrete examples of cases where a range type might want to do some representational optimization? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
