I was thinking along the kind of missing index Tom was arguing about for RI checks, that may be helped if an appropriate index is available.
I'm not sure what could be done, even with the query, in the general case. How to guess what index would help make a better plan? It depends on the optimiser itself, on what kind of indexes could be built, and so on. That's more human expect work than tool work.
Also, if they have a partial index on the FK, it's not good enough! In CVS, IS NOT NULL partial indexes should be used, but in general all others still won't...
Chris
---------------------------(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
