Hi, Bruce, Bruce Momjian wrote: >>Ahh. There's a hack to do that by defining a new opclass that reverses < >>and >, and then doing ORDER BY project_id, id, date USING new_opclass. >> >>I think there's a TODO about this, but I'm not sure... > > Yes, and updated: > > * Allow the creation of indexes with mixed ascending/descending > specifiers > > This is possible now by creating an operator class with reversed sort > operators. One complexity is that NULLs would then appear at the start > of the result set, and this might affect certain sort types, like > merge join. I think it would be better to allow "index zig-zag scans" for multi-column index.[1] So it traverses in a given order on the higher order column, and the sub trees for each specific high order value is traversed in reversed order.
