Re: Weird 8.2.4 performance

Mark Kirkwood wrote:
>
> 8.2 is deciding to use a bitmap index scan on taskid_taskinstance_key,
> which seems to be slower (!) than a plain old index scan that 8.0 is
> using. A dirty work around is to disable bitmap scans via:

I'm having difficulty figuring out why it's doing this at all. There's
only one index involved, and it's over the primary-key to boot!

An EXPLAIN ANALYSE with enable_bitmapscan off should say why PG thinks
the costs are cheaper than they actually are.

PS - well worded question Kurt. All the relevant information neatly laid
out, explain analyse on both platforms - you should be charging to let
people help ;-)

--
   Richard Huxton
   Archonet Ltd