Re: Multi-pass planner
От | Dimitri Fontaine |
---|---|
Тема | Re: Multi-pass planner |
Дата | |
Msg-id | m2ip42qg9t.fsf@2ndQuadrant.fr обсуждение исходный текст |
Ответ на | Re: Multi-pass planner (Robert Haas <robertmhaas@gmail.com>) |
Ответы |
Re: Multi-pass planner
Re: Multi-pass planner |
Список | pgsql-hackers |
Robert Haas <robertmhaas@gmail.com> writes: > for estimate_worstcase_fraction. So, when computing the cost of a > path, we'd compute our current expected-case estimate, and also a > worst-case estimate, and then compute the final cost as: There also was the idea for the executor to be able to handle alternate plans and some heuristic to determine that the actual cost of running a plan is much higher than what's been estimated, so much so as to switch to starting from scratch with the other plan instead. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support
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