On Tue, Jul 20, 2004 at 10:18:19PM -0400, Rod Taylor wrote: > I've taken a look and managed to cut out quite a bit of used time. > You'll need to confirm it's the same results though (I didn't -- it is > the same number of results (query below)
It looks very much like the same results. > Secondly, I had no luck getting the hashjoin but this probably doesn't > matter. I've assumed that the number of users will climb faster than the > product set offered, and generated additional data via the below command > run 4 times: Actually, the number of users won't climb that much faster; what will probably increase is the number of opinions. > I found that by this point, the hashjoin and mergejoin have essentially > the same performance -- in otherwords, as you grow you'll want the > mergejoin eventually so I wouldn't worry about it too much. Hm, OK. > -- Plain join okay since o12.correlation <> 0 > -- eliminates any NULLs anyway. > -- Was RIGHT JOIN OK, that makes sense (although I don't really see why it should be faster). > -- Was old Left join > WHERE o3.prodid NOT IN (SELECT prodid > FROM opinions AS o4 > WHERE uid = 1355) As my server is 7.2 and not 7.4, that obviously won't help much :-) Thanks anyway, though -- we'll upgrade eventually, and it'll help then. /* Steinar */ -- Homepage: http://www.sesse.net/ ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
