Re: Optimizer hook
| От | Tom Lane |
|---|---|
| Тема | Re: Optimizer hook |
| Дата | |
| Msg-id | 8067.1190760570@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Re: Optimizer hook (Julius Stroffek <Julius.Stroffek@Sun.COM>) |
| Ответы |
Re: Optimizer hook
|
| Список | pgsql-patches |
Julius Stroffek <Julius.Stroffek@Sun.COM> writes:
> Parts of the result path might be found by geqo and parts of it by
> regular algorithm.
Why would you care? Seems like forcing that to not happen is actively
making it stupider.
> If there is no way of how to make the code work then it makes no sense
> to put the hook to the place I am proposing. It works for me, but I have
> not tested that very well yet. If I would swap calls to geqo
> and make_one_rel_by_joins it will not work. Therefore there might be
> an issue I do not know about yet.
Well, I can see one likely problem: list_copy is a shallow copy and
thus doesn't ensure that the second set of functions sees the same input
data structures as the first. I know that geqo has to go through some
special pushups to perform multiple invocations of the base planner,
and I suspect you need that here too. Look at geqo_eval().
regards, tom lane
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