Re: Glacially slow nested SELECT

Demitri Muna <thatsanicehatyouhave(at)mac(dot)com> writes:
> On 15 Jan 2007, at 16:21, Tom Lane wrote:
>> It looks like spview is a view with an embedded ORDER BY? IIRC that
>> prevents any meaningful optimization of joins to it --- and
>> WHERE-IN-sub-SELECT is a kind of join.

> Thanks for the pointer Tom; removing the ORDER BY from the view did
> the trick. Is there a reason that the sorting can't be done after the
> selection?

Well, it'd require major revisions to the planner, and it'd break
various queries that depend on the planner honoring sub-select ORDER BY
(people use that to guarantee the order in which values are fed to
custom aggregates, for instance).

regards, tom lane