The result set should have 31 rows, that is correct. On Mon, Feb 23, 2009 at 7:53 PM, Scott Marlowe <scott.marl...@gmail.com>wrote:
> On Mon, Feb 23, 2009 at 6:24 PM, Farhan Husain <russ...@gmail.com> wrote: > This sort here: > > > -> Sort (cost=565372.46..568084.16 rows=1084680 width=74) (actual > > time=5410606.604..5410606.628 rows=31 loops=1) > > Sort Key: a1.subj > > Sort Method: quicksort Memory: 489474kB > > -> Seq Scan on jena_g1t1_stmt a1 (cost=0.00..456639.59 > > rows=1084680 width=74) (actual time=0.043..44005.780 rows=3192000 > loops=1) > > Seems to be the problem. There are a few things that seem odd, the > first is that it estimates it will return 1M ros, but returns only 31. > The other is that sorting 31 rows is taking 5410606 milliseconds. > > My first guess would be to crank up the statistics on a1.subj to a few > hundred (going up to a thousand if necessary) re-analyzing and seeing > if the query plan changes. > > I'm not expert enough on explain analyze to offer any more. > -- Mohammad Farhan Husain Research Assistant Department of Computer Science Erik Jonsson School of Engineering and Computer Science University of Texas at Dallas
