Re: PostgreSQL 8.3, libpq and WHERE CURRENT OF

From: Sebastien FLAESCH <sf(at)4js(dot)com>
To: "Florian G(dot) Pflug" <fgp(at)phlo(dot)org>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <heikki(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org, Guillaume ERGAND <ger(at)4js(dot)com>
Subject: Re: PostgreSQL 8.3, libpq and WHERE CURRENT OF
Date: 2007-10-28 07:28:19
Message-ID: 47243A13.70607@4js.com
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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
>

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