Clive Page <clive(dot)page(at)cantab(dot)net> writes:
> Is there a way of forcing the use of Rtree indexing in v8.4,
No, because the rtree code is gone entirely. We took it out on the
basis of tests showing that the gist implementation performed as well
or better. I'm not sure why it's not working for you, but if you
can provide a more complete test case, we could look into it.
One thing to check into right away is whether the system is even
trying to use the index --- what does EXPLAIN show about it?
Do you by any chance have EXPLAIN output for the same query on the
old system? What was the old PG version, anyway?
regards, tom lane