Re: should we have a fast-path planning for OLTP starjoins? - Mailing list pgsql-hackers

On 11/24/25 21:55, Robert Haas wrote:
> On Sun, Nov 23, 2025 at 9:39 AM Tomas Vondra <tomas@vondra.me> wrote:
>>> 1. I do not think I believe the premise that the dimension tables
>>> typically won't have restriction clauses.  ISTM that a typical
>>> query might be like
>>>
>>>       select sum(o.total_price) from
>>>       orders o
>>>       join customers c on c.id = o.c_id
>>>       join products p on p.id = o.p_id
>>>       where c.customer_name = 'Wile E Coyote'
>>>       and p.product_name = 'Rocket Skates';
>>>
>>
>> Good question. I don't have a great evidence such joins to dimensions
>> (without additional restrictions) are a common case. It's partially a
>> guess and partially based on my past experience.
> 
> In my experience, restriction clauses on dimension tables are very common.
> 

Sure, but does that imply the inverse case (dimensions without non-join
restrictions) are not? I'm not sure.


regards

-- 
Tomas Vondra