On Thu, Mar 30, 2006 at 02:31:34PM +0200, Steinar H. Gunderson wrote:
Well, it's logical enough; it scans along activity_id until it finds one with state=10000 or state=10001. You obviously have a _lot_ of records with low activity_id and state none of these two, so Postgres needs to scan all those records before it founds 100 it can output. This is the “startup cost” you're seeing.
Yes. And the estimates are bad enough (orders of magnitude) that I can't help but wonder whether pg could come up with a better plan with better statistics:
-> Index Scan using activity_pk on activity (cost=0.00..40717259.91 rows=6538650 width=8) (actual time=207356.050..207356.722 rows=100 loops=1) Filter: ((state = 10000) OR (state = 10001))
Mike Stone
