Thread: Re: [COMMITTERS] pgsql: Improve performance offind_all_inheritors()

Hi, Robert.

> I'm a little worried that this will be noticeably slower when the
> number of partitions is small, like 4 or 8 or 16.  In other places,
> we've found it necessary to support both a list-based strategy and a
> hash-based strategy to avoid regressing small cases (e.g.
> join_rel_list + join_rel_hash in PlannerInfo, ResourceArray in
> resowner.c, etc).

I've checked it [1]. Apparently in this particular case patches make code
faster on small amount of partitions as well.

[1] https://postgr.es/m/20170324132258.GB16830%40e733.localdomain

--
Best regards,
Aleksander Alekseev

On Tue, Mar 28, 2017 at 3:59 PM, Aleksander Alekseev
<a.alekseev@postgrespro.ru> wrote:
> Hi, Robert.
>
>> I'm a little worried that this will be noticeably slower when the
>> number of partitions is small, like 4 or 8 or 16.  In other places,
>> we've found it necessary to support both a list-based strategy and a
>> hash-based strategy to avoid regressing small cases (e.g.
>> join_rel_list + join_rel_hash in PlannerInfo, ResourceArray in
>> resowner.c, etc).
>
> I've checked it [1]. Apparently in this particular case patches make code
> faster on small amount of partitions as well.

Huh.  Well, in that case, cool.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company