From: | "Jim C(dot) Nasby" <decibel(at)decibel(dot)org> |
---|---|
To: | Dawid Kuroczko <qnex42(at)gmail(dot)com> |
Cc: | Lincoln Yeoh <lyeoh(at)pop(dot)jaring(dot)my>, Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: Converting MySQL tinyint to PostgreSQL |
Date: | 2005-07-19 07:21:05 |
Message-ID: | 20050719072105.GN38511@decibel.org |
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Thread: | |
Lists: | pgsql-general |
On Tue, Jul 19, 2005 at 02:02:28AM +0200, Dawid Kuroczko wrote:
> On 7/18/05, Lincoln Yeoh <lyeoh(at)pop(dot)jaring(dot)my> wrote:
> > However, maybe padding for alignment is a waste on the disk - disks being
> > so much slower than CPUs (not sure about that once the data is in memory ).
> > Maybe there should be an option to reorder columns so that less space is
> > wasted.
>
> Out of curiosity, do I understand right that if I create table
>
> CREATE TABLE sample1 (
> a boolean,
> b int,
> c boolean
> );
>
> ...it will take more storage than:
>
> CREATE TABLE sample2 (
> b int,
> a boolean,
> c boolean
> );
>
> ...I don't think such ordering should matter, but I would like to know
> how it really is. :)
Actually, I believe that's the case with just about every database,
though of course each one has different alignment constraints. The point
is that I don't know of any database that will silently re-order fields
under the covers to optimize storage.
--
Jim C. Nasby, Database Consultant decibel(at)decibel(dot)org
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