Re: slow "IN" clause

On lun, 2006-04-10 at 12:44 +0800, Qingqing Zhou wrote:
> <FavoYang(at)gmail(dot)com> 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.