X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 24C249F9316 for ; Thu, 18 May 2006 13:54:57 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 41646-05 for ; Thu, 18 May 2006 13:54:47 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey- Received: from wx-out-0102.google.com (wx-out-0102.google.com [66.249.82.207]) by postgresql.org (Postfix) with ESMTP id 931909FA48C for ; Thu, 18 May 2006 13:54:47 -0300 (ADT) Received: by wx-out-0102.google.com with SMTP id s7so99467wxc for ; Thu, 18 May 2006 09:54:47 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=maQX0a2fa0qOyqlX0cokygznrbhkkMWbU0Eh+3I2Vhplbuz9uvukijB7EHm+e11n4UYx774boSPCYwZ7+rCJTyOVWG0ksH3luaFpo8TYmRF+BPBcmRy0CA+fkQP+mNXkWz1Shgjp4HmZedK+Aapj+iXkPiRr+rU48l1GJHwclkM= Received: by 10.70.47.11 with SMTP id u11mr877743wxu; Thu, 18 May 2006 09:54:46 -0700 (PDT) Received: by 10.70.8.11 with HTTP; Thu, 18 May 2006 09:54:46 -0700 (PDT) Message-ID: Date: Thu, 18 May 2006 18:54:46 +0200 From: "Guillaume Lelarge" To: "Andrew Sullivan" Subject: Re: Add column and specify the column position in a table Cc: pgsql-sql@postgresql.org In-Reply-To: <20060518155829.GE29472@phlogiston.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <446B9418.3080700@encs.concordia.ca> <446C0BC0.7050805@gmail.com> <20060518140014.GA3122@surnet.cl> <20060518155829.GE29472@phlogiston.dyndns.org> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/147 X-Sequence-Number: 25178 2006/5/18, Andrew Sullivan : > On Thu, May 18, 2006 at 05:43:19PM +0200, Guillaume Lelarge wrote: > > Do you mean that, using "alter table test add column" with the "after" > > option, MySQL creates a new table, populates it with the old table > > data and finally drops the old table ? I mean, there's the same > > performance problem with big tables ? > > MySQL does that for a great deal of its DDL. Yes, the performance is > awful for this on big tables. > > The reason I didn't answer the OP's question, though, is that I can't > think of a legitimate reason to do this anyway. The physical layout > of the columns should not be of concern to the developer, who should > be naming the columns anyway. > I totally agree on the physical layout. Just being curious :) --=20 Guillaume.