Re: Optimizer isn't perfect - Mailing list pgsql-general

From Alvaro Herrera
Subject Re: Optimizer isn't perfect
Date
Msg-id 20030831200941.GC30107@dcc.uchile.cl
Whole thread Raw
In response to Optimizer isn't perfect  (Greg Stark <gsstark@mit.edu>)
List pgsql-general
On Fri, Aug 29, 2003 at 10:37:32AM -0400, Greg Stark wrote:

> Except if it guesses wrong by assuming it isn't selective it would be maybe
> 50% slower doing lots of index lookups instead of a more efficient full table
> scan and join. If it guesses wrong by assuming it'll be very selective as it
> is in this case then it's 1000% slower doing repeated full table scans.

Well, there are operators that need some work.  I am seeing less than
ideal behaviour with OVERLAPS, but I think it isn't even documented...

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"In a specialized industrial society, it would be a disaster
to have kids running around loose." (Paul Graham)

pgsql-general by date:

Previous
From: Michael Meskes
Date:
Subject: Re: About GPL and proprietary software
Next
From: Ron Johnson
Date:
Subject: Re: About GPL and proprietary software