Received: from localhost (maia-3.hub.org [200.46.204.184])
	by postgresql.org (Postfix) with ESMTP id ED2239FA145
	for <pgsql-sql-postgresql.org@postgresql.org>;
	Wed, 17 Jan 2007 08:59:18 -0400 (AST)
Received: from postgresql.org ([200.46.204.71])
	by localhost (mx1.hub.org [200.46.204.184]) (amavisd-new, port 10024)
	with ESMTP id 81860-05 for <pgsql-sql-postgresql.org@postgresql.org>;
	Wed, 17 Jan 2007 08:58:59 -0400 (AST)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.4
Received: from main2.mycybernet.net (main2.mycybernet.net [209.222.63.140])
	by postgresql.org (Postfix) with ESMTP id D3CD49FB223
	for <pgsql-sql@postgresql.org>; Wed, 17 Jan 2007 08:59:03 -0400 (AST)
Received: from 227-54-222-209.mycybernet.net ([209.222.54.227]
	helo=phlogiston.dydns.org)
	by main2.mycybernet.net with esmtp (Exim 4.62)
	(envelope-from <ajs@phlogiston.dyndns.org>) id 1H7AXS-0007yB-1e
	for pgsql-sql@postgresql.org; Wed, 17 Jan 2007 08:09:14 -0500
Received: by phlogiston.dydns.org (Postfix, from userid 1000)
	id 2683041A2; Wed, 17 Jan 2007 07:58:57 -0500 (EST)
Date: Wed, 17 Jan 2007 07:58:57 -0500
From: Andrew Sullivan <ajs@crankycanuck.ca>
To: pgsql-sql@postgresql.org
Subject: Re: Postgresql & Oracle Heteregenous services - strange behaviour
Message-ID: <20070117125857.GD19527@phlogiston.dyndns.org>
References: <pan.2007.01.17.12.52.25.379331@gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <pan.2007.01.17.12.52.25.379331@gmail.com>
User-Agent: Mutt/1.5.9i
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Archive-Number: 200701/68
X-Sequence-Number: 27220

On Wed, Jan 17, 2007 at 01:52:25PM +0100, Marcin St?pnicki wrote:
> I see this in postgresql logs:
> 
> [6210]   DEBUG:  query: select * from "zew_patients"
> [6210]   DEBUG:  query:  SELECT "A1"."p_nr_pesel" FROM "zew_patients"
> "A1" WHERE ("A1"."p_patient_id" = 19300)
> 
> The point is, I don't why oh why the first select is issued (some cache?),

<speculation level="rank">

I bet it's getting the column list from the table or some such thing. 
This is a lousy way to do it (the information_schema would be more
correct, although maybe no faster).

The reason it isn't repeated, I bet, is that your connection is
persistent, so the information gets cached.

</speculation>

A
-- 
Andrew Sullivan  | ajs@crankycanuck.ca
Everything that happens in the world happens at some place.
		--Jane Jacobs