Re: [HACKERS] indexes and floats

From: Vince Vielhaber <vev(at)michvhf(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: hackers(at)postgreSQL(dot)org, "Thomas G(dot)Lockhart" <lockhart(at)alumni(dot)caltech(dot)edu>
Subject: Re: [HACKERS] indexes and floats
Date: 1998-08-04 15:08:03
Message-ID: XFMail.980804110803.vev@michvhf.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers


On 04-Aug-98 Tom Lane wrote:

> OK, that sounds plausible. But in my examples,
>
> play=> explain select x from f8 where x = 500;
> NOTICE: QUERY PLAN:
> Seq Scan on f8 (cost=40.00 size=100 width=8)
>
> Your explanation implies that here, the parser is converting to
> select x from f8 where int4(x) = 500;
> which is wrong for the same accuracy-loss reasons you cite later.
> (And if that isn't what it's doing, what then?)
>
> I think it would be a good idea if someone actually dug into this
> and verified what's going on. I have found some other cases that
> lead me to think there's more to this than we understand just yet.
> With an index on an int4 field, I get

What file(s) are these decisions actually made in?

Vince.
--
==========================================================================
Vince Vielhaber -- KA8CSH email: vev(at)michvhf(dot)com flame-mail: /dev/null
# include <std/disclaimers.h> TEAM-OS2
Online Searchable Campground Listings http://www.camping-usa.com
"There is no outfit less entitled to lecture me about bloat
than the federal government" -- Tony Snow
==========================================================================

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Thomas G. Lockhart 1998-08-04 16:37:54 Re: [HACKERS] indexes and floats
Previous Message Bruce Momjian 1998-08-04 15:04:46 EXPLAIN VERBOSE