Re: *_collapse_limit, geqo_threshold - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: *_collapse_limit, geqo_threshold
Date
Msg-id 20090707221011.GR7694@alvh.no-ip.org
Whole thread Raw
In response to Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: *_collapse_limit, geqo_threshold  (Tom Lane <tgl@sss.pgh.pa.us>)
List 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.


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: bytea vs. pg_dump
Next
From: Mark Mielke
Date:
Subject: Re: 8.4, One-Time Filter and subquery ( ... FROM function() union all ... )