With the just-committed changes in PathKey representation, the core backend is now pretty well invested in the assumption that index AMs that can deliver sorted results will use btree-compatible strategy numbers for their order-related operators. This doesn't seem to me to be any huge limitation (a new AM might possibly define additional operator strategies, but that needn't stop it from using 1-5 with the same meanings as btree). So I'm thinking that the pg_am columns amorderstrategy and amdescorder are redundant and should be replaced with a simple boolean, "amcansort" perhaps. Any objections?
regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq