On Thu, 20 May 2004, Bruno Wolff III wrote: > On Wed, May 19, 2004 at 15:17:01 +0200, > Atesz <[EMAIL PROTECTED]> wrote: > > > > I'd like to ask why the index scaning can't move on an index in > > multi-order directions (For exapmle: 1.column: forward, 2.column: > > backward and 3.column: forward again)? So I wouldn't have to use so many > > indexes. Has somebody tried to implement this idea in Postgres or is > > there a more difficult reason in the postgres implementation which > > cause this defect? > > Because there is only one order on an index. So you can only go forward > and backwards over all of the columns/functions.
If you're willing to make multiple visits you might be able to scan past and back but I don't know how that'd work for our indexes. ---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match