On Fri, Nov 8, 2013 at 6:04 AM, Jan Walter <j...@commontongue.com> wrote:
> Hi, > > I would like to know, how does the size of the IN list affect query > planner. > I have a query > > select distinct on (event_id, tag_id) et.id, > e.id as event_id, t.id as tag_id, t.name, > t.user_id, t.shared, t.color, > case > when ea.id <> e.id then true > else false > end as inherited > from do_event e > join do_event ea on (ea.tree_id = e.tree_id and ea.lft <= e.lft and > ea.rght >= e.rght) > join do_event_tags et on (et.event_id = ea.id) > join do_tag t on (t.id = et.tag_id) > where e.id in (LIST_OF_INTEGERS) and > (t.user_id = 14 or t.shared) > order by event_id, tag_id, inherited; > Looking at your EXPLAIN ANALYZE plan I was immediately reminded of this article http://www.datadoghq.com/2013/08/100x-faster-postgres-performance-by-changing-1-line/, where changing the array to a VALUES() clause was a huge win for them.
