On Fri, 2009-04-03 at 10:04 -0400, Tom Lane wrote: > Matthew Wakeling <matt...@flymine.org> writes: > > On Fri, 3 Apr 2009, Robert Haas wrote: > >> Why not just use SQL to do the join? > > > Because the merge condition is: > > > WHERE l1.start <= l2.end AND l2.start <= l1.end > > > and merge joins in postgres only currently cope with the case where the > > merge condition is an equals relationship.
(snip) > I don't actually believe that a standard merge join algorithm will work > with an intransitive join condition ... I think it's a common enough problem that having a non-standard join algorithm written for that case would be interesting indeed. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
