Обсуждение: Re: [HACKERS] [COMMITTERS] pgsql: Collect and use multi-column dependency stats

On 5 April 2017 at 18:48, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
>> Collect and use multi-column dependency stats
>
> The buildfarm is unhappy about the fact that this changed the API
> for clauselist_selectivity().  I am not convinced that that change
> was a good idea, so before telling FDW authors that they need to
> change their code, I'd like to hear a defense of the API change.
> Why not just use the existing varRelid parameter for that?  Why
> is there an assumption that only one rel's extended stats will
> ever be of interest?  This function does get used for join clauses.

Point noted. Reading thread and hope to fix today.

-- 
Simon Riggs                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

On 7 April 2017 at 00:47, Simon Riggs <simon@2ndquadrant.com> wrote:
> On 5 April 2017 at 18:48, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Simon Riggs <simon@2ndQuadrant.com> writes:
>>> Collect and use multi-column dependency stats
>>
>> The buildfarm is unhappy about the fact that this changed the API
>> for clauselist_selectivity().  I am not convinced that that change
>> was a good idea, so before telling FDW authors that they need to
>> change their code, I'd like to hear a defense of the API change.
>> Why not just use the existing varRelid parameter for that?  Why
>> is there an assumption that only one rel's extended stats will
>> ever be of interest?  This function does get used for join clauses.
>
> Point noted. Reading thread and hope to fix today.

I've attached a rebased patch which fixes up the conflict with the
BRIN cost estimate patch which went in a short while ago.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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On 6 April 2017 at 17:41, David Rowley <david.rowley@2ndquadrant.com> wrote:
> On 7 April 2017 at 00:47, Simon Riggs <simon@2ndquadrant.com> wrote:
>> On 5 April 2017 at 18:48, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> Simon Riggs <simon@2ndQuadrant.com> writes:
>>>> Collect and use multi-column dependency stats
>>>
>>> The buildfarm is unhappy about the fact that this changed the API
>>> for clauselist_selectivity().  I am not convinced that that change
>>> was a good idea, so before telling FDW authors that they need to
>>> change their code, I'd like to hear a defense of the API change.
>>> Why not just use the existing varRelid parameter for that?  Why
>>> is there an assumption that only one rel's extended stats will
>>> ever be of interest?  This function does get used for join clauses.
>>
>> Point noted. Reading thread and hope to fix today.
>
> I've attached a rebased patch which fixes up the conflict with the
> BRIN cost estimate patch which went in a short while ago.

Looks enough to me, for now at least. Minor comment added.

-- 
Simon Riggs                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services