Thanks for the tip! Regards, Behrang (sent from my mobile)
On Mon, Oct 7, 2019, 07:37 Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > On Tue, Oct 01, 2019 at 11:42:33PM +1000, Behrang Saeedzadeh wrote: > >Thanks. That eliminated the bottleneck! > > > >Any ideas why adding ORDER BY to the subquery also changes the plan in a > >way that eliminates the bottleneck? > > > > IIRC the ORDER BY clause makes it impossible to "collapse" the subquery > into the main (upper) one, and it probably happens to constrict the > choices so that the planner ends up picking a good plan. I guess adding > "OFFSET 0" to the subquery would have the same effect. > > > regards > > -- > Tomas Vondra http://www.2ndQuadrant.com > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services >
