Message-ID: <47243A13.70607@4js.com>
Date: Sun, 28 Oct 2007 08:28:19 +0100
From: Sebastien FLAESCH <sf@4js.com>
Organization: Four J's Development Tools
User-Agent: Thunderbird 1.5.0.9 (X11/20061220)
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To: "Florian G. Pflug" <fgp@phlo.org>
CC: Tom Lane <tgl@sss.pgh.pa.us>,
 Heikki Linnakangas <heikki@enterprisedb.com>,
	pgsql-hackers@postgresql.org, Guillaume ERGAND <ger@4js.com>
Subject: Re: PostgreSQL 8.3, libpq and WHERE CURRENT OF
References: <4721BAFE.3080601@4js.com> <4721BF34.80901@enterprisedb.com>
	<4721DECF.80401@4js.com> <10801.1193404182@sss.pgh.pa.us>
	<4721F289.7080800@4js.com> <4721F33F.10704@4js.com>
	<472369E9.1050808@phlo.org>
In-Reply-To: <472369E9.1050808@phlo.org>
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Florian,

Do you mean WITH HOLD cursors (+ FOR UPDATE) can also be used to do
DELETE/UPDATE WHERE CURRENT OF (i.e. outside transactions) ?

 From my experience this is an Informix-only feature, but if PostgreSQL
supports that it would help a lot to migrate existing applications.

I understand it's not a usual feature - one typically SELECT FOR UPDATE
and DELETE / UPDATE WHERE CURRENT OF in a transaction block.

I will give it a try anyway.

Further, I was wondering if DECLARE CURSOR could be slower as plain
SELECT statements. I will see this rapidly anyway so if someone can
give me some tips about the overhead/cost of moving to DECLARE CURSOR,
it would help me a lot.

Remember I am talking about a driver for our VM = moving to DECLARE
CURSOR would apply to all SELECT statements used in an application.

Thanks
Seb

Florian G. Pflug wrote:
> Sebastien FLAESCH wrote:
>> Forget this one, just missing the WITH HOLD option... Must teach 
>> myself a bit
>> more before sending further mails. Seb
> 
> AFAIK you cannot use "WITH HOLD" together with updateable cursors.
> I might be wrong, though...
> 
> regards, Florian Pflug
>