On lun, 2006-04-10 at 12:44 +0800, Qingqing Zhou wrote: > <FavoYang@xxxxxxxxx> wrote > > I have a slow sql: > > SELECT * FROM mytable WHERE id IN (1,3,5,7,....3k here...); > > mytable is about 10k rows. > > > > if don't use the "IN" clause, it will cost 0,11 second, otherwise it > > will cost 2.x second > > I guess pg use linear search to deal with IN clause, is there any way > > to let pg use other search method with IN clause? (ex.Binary Search or > > hash Search) > > > > If you can put (1, 3, .., 3k) in a table, PG may choose a hash join. And maybe using SELECT * FROM yourtable WHERE id < 6002 AND id % 2 = 1; turns out to be faster, if we are allowed to extrapolate from the example. V.
