On 20 June 2017 at 07:49, Tom Lane wrote:
> I'm not totally satisfied that there isn't any case where the smallest
> selectivity hack is appropriate. In the example you're showing here,
> the FK columns are independent so that we get more or less the right
> answer with or without the FK. But in
David Rowley writes:
> On 22 May 2017 at 16:10, David Rowley wrote:
>> I also just noticed that I don't think I've got ANTI join cases
>> correct in the patch I sent. I'll look at that now.
> I've attached an updated patch.
> This one is much less invasive than my original attempt.
Sorry for no
On 22 May 2017 at 16:10, David Rowley wrote:
> I also just noticed that I don't think I've got ANTI join cases
> correct in the patch I sent. I'll look at that now.
I've attached an updated patch.
This one is much less invasive than my original attempt.
There are two fundamental changes here:
On 21 May 2017 at 07:56, Tom Lane wrote:
> I'm entirely unconvinced by this patch --- it seems to simply be throwing
> away a lot of logic. Notably it lobotomizes the FK code altogether for
> semi/antijoin cases, but you've not shown any example that even involves
> such joins, so what's the argu
David Rowley writes:
> I've been analyzing a reported regression case between a 9.5 plan and
> a 9.6 plan. I tracked this down to the foreign key join selectivity
> code, specifically the use_smallest_selectivity code which is applied
> to outer joins where the referenced table is on the outer sid
On 18 May 2017 at 20:28, David Rowley wrote:
> A vastly simplified example case is:
>
> create table fkest (a int, b int, c int unique, primary key(a,b));
> create table fkest1 (a int, b int, primary key(a,b));
>
> insert into fkest select x/10,x%10, x from generate_Series(1,400) x;
> insert into
I've been analyzing a reported regression case between a 9.5 plan and
a 9.6 plan. I tracked this down to the foreign key join selectivity
code, specifically the use_smallest_selectivity code which is applied
to outer joins where the referenced table is on the outer side of the
join.
A vastly simpl
