| From: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, Dimitri Fontaine <dim(at)hi-media(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: *_collapse_limit, geqo_threshold |
| Date: | 2009-07-07 22:10:12 |
| Message-ID: | 20090707221011.GR7694@alvh.no-ip.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
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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