"Julian Scarfe" <julian(at)avbrief(dot)com> writes:
>> Without the EXPLAIN ANALYZE output, nobody can say whether you have
>> interpreted your performance problem correctly or not.
> Fair enough, Tom.
Okay, so the "expensive function" isn't as expensive as all that ---
it seems to be adding only a few msec to the total runtime. The
problem you've got is that you need a nestloop-with-inner-indexscan
plan type, where the inner side is an Append group (that is, an
inheritance tree) --- and 8.1 doesn't know how to create such a plan.
If you can update to 8.2 or later it should get better.
regards, tom lane