Re: *_collapse_limit, geqo_threshold

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От Alvaro Herrera
Тема Re: *_collapse_limit, geqo_threshold
Дата
Msg-id 20090707221011.GR7694@alvh.no-ip.org
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Ответ на Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane escribió:

> My own thought is that from_collapse_limit has more justification,
> since it basically acts to stop a subquery from being flattened when
> that would make the parent query too complex, and that seems like a
> more understandable and justifiable behavior than treating JOIN
> syntax specially.

Isn't that what we use OFFSET 0 for?  That one has also the nice
property that you can actually specify which subquery you want to
prevent from being flattened.

Personally I have never seen a case where the collapse_limits were
useful tools.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.


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