On Wed, 19 Jan 2005, Dan Langille wrote: > Hi folks, > > Running on 7.4.2, recently vacuum analysed the three tables in > question. > > The query plan in question changes dramatically when a WHERE clause > changes from ports.broken to ports.deprecated. I don't see why. > Well, I do see why: a sequential scan of a 130,000 rows. The query > goes from 13ms to 1100ms because the of this. The full plans are at > http://rafb.net/paste/results/v8ccvQ54.html > > I have tried some tuning by: > > set effective_cache_size to 4000, was 1000 > set random_page_cost to 1, was 4 > > The resulting plan changes, but no speed improvment, are at > http://rafb.net/paste/results/rV8khJ18.html > > Any suggestions please?
As a question, what does it do if enable_hashjoin is false? I'm wondering if it'll pick a nested loop for that step for the element/ports join and what it estimates the cost to be. ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org