By the way, now that it works, I am glad to prove you wrong on the optimizer
behavior on 7.1.3 :-)
My query
select * from r where d = 8;
still results in sequential scan:
Seq Scan on r (cost=0.00..527.16 rows=7191 width=16)
However, the query
select * from r where d = 1;
now results in index scan.
Index Scan using r_d_idx on r (cost=0.00..308.45 rows=719 width=16)
Not to say I am sufficiently confused - now to go on with some more testing...
Daniel