Skip site navigation (1) Skip section navigation (2)

Re: Add dblink function to check if a named connection exists

From: "Asko Oja" <ascoja(at)gmail(dot)com>
To: "Joe Conway" <mail(at)joeconway(dot)com>
Cc: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Tommy Gildseth" <tommy(dot)gildseth(at)usit(dot)uio(dot)no>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Add dblink function to check if a named connection exists
Date: 2008-06-02 06:59:37
Message-ID: ecd779860806012359q41bb4a1fk341f495b63c1453a@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Just use plproxy and skip all the hassle of dblink :)

On Mon, Jun 2, 2008 at 3:14 AM, Joe Conway <mail(at)joeconway(dot)com> wrote:

> Tom Lane wrote:
>
>> Tommy Gildseth <tommy(dot)gildseth(at)usit(dot)uio(dot)no> writes:
>>
>>> One obvious disadvantage of this approach, is that I need to connect and
>>> disconnect in every function. A possible solution to this, would be having a
>>> function f.ex dblink_exists('connection_name') that returns true/false
>>> depending on whether the  connection already exists.
>>>
>>
>> Can't you do this already?
>>
>>        SELECT 'myconn' = ANY (dblink_get_connections());
>>
>> A dedicated function might be a tad faster, but it probably isn't going
>> to matter compared to the overhead of sending a remote query.
>>
>
> I agree. The above is about as simple as
>  SELECT dblink_exists('dtest1');
> and probably not measurably slower. If you still think a dedicated function
> is needed, please send the output of some performance testing to justify it.
>
> If you really want the notational simplicity, you could use an SQL function
> to wrap it:
>
> CREATE OR REPLACE FUNCTION dblink_exists(text)
> RETURNS bool AS $$
>  SELECT $1 = ANY (dblink_get_connections())
> $$ LANGUAGE sql;
>
> contrib_regression=# SELECT dblink_exists('dtest1');
>  dblink_exists
> ---------------
>  f
> (1 row)
>
> I guess it might be worthwhile adding the SQL function definition to
> dblink.sql.in as an enhancement in 8.4.
>
> Joe
>
>
>
> --
> Sent via pgsql-hackers mailing list (pgsql-hackers(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-hackers
>

In response to

pgsql-hackers by date

Next:From: Dave PageDate: 2008-06-02 07:37:36
Subject: Re: Overhauling GUCS
Previous:From: Robert HodgesDate: 2008-06-02 06:51:29
Subject: Re: Table rewrites vs. pending AFTER triggers

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group