I think Kevin mentioned this before and he wasn't sure why either but thought I would bring it up since I'm not clear what the reason for this is. Our ST_OrderingEquals function is a short-hand for SELECT $1 && $2 AND $1 ~= $2 But ~= already uses a GIST index doesn't it? So why this extra $1 && $2 check? Is the && faster to compute? Or have higher selectivity? Thanks, Regina