Some additional thoughts: what appears to take the most time (i.e.
account for the highest cost in the explain), is _not_ running the
function itself (cost=0.00..0.01), but comparing the result from that
function with the name1 column in the mappings table
(cost=0.00..35935.05). Am I right? (See EXPLAIN in previous post.) If
so: that's pretty strange, because the name1-column in the mappings
table is indexed...
jan.