Improve choose_custom_plan for initial partition prune case
| От | Andy Fan |
|---|---|
| Тема | Improve choose_custom_plan for initial partition prune case |
| Дата | |
| Msg-id | CAKU4AWqUJmQdu9qf_pXxBYETkiXhTaXAQ_qtX7wxeLw27phdOw@mail.gmail.com обсуждение исходный текст |
| Ответы |
Re: Improve choose_custom_plan for initial partition prune case
Re: Improve choose_custom_plan for initial partition prune case |
| Список | pgsql-hackers |
Given the plan example:
city_id int not null,
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (logdate);
CREATE TABLE measurement_y2006m02 PARTITION OF measurement
FOR VALUES FROM ('2006-02-01') TO ('2006-03-01');
CREATE TABLE measurement_y2006m03 PARTITION OF measurement
FOR VALUES FROM ('2006-03-01') TO ('2006-04-01');
prepare s as select * from measurement where logdate = $1;
execute s('2006-02-01').
The generic plan will probably not be chosen because it doesn't reduce the cost
which can be reduced at initial_prune while the custom plan reduces such cost
at planning time. which makes the cost comparison not fair. I'm thinking if we can
get an estimated cost reduction of initial_prunne for generic plan based on the
partition pruned at plan time from custom plan and then reducing
such costs from the generic plan. I just went through the related code but
didn't write anything now. I'd like to see if this is a correct direction to go.
Best Regards
Andy Fan
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