Curious bit of synchronicity, related discussion going on in comp.arch on same topic, lurkers like me might appreciate the explanation given in
http://groups.google.com/groups?selm=svudnRBY5twrXG6jXTWJkQ%40metrocast.net ---------------------------(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