Thanks. This is what I want to know :-)
Regards,
Billow
>Yeah, what he wants is to implement a function in Postgres which does
>something like an LDAP or DNS lookup or something like that.
>Sure you can do this. The only tricky bit is the thing you mentioned about
>reusing the connection. You could always leave the connection in a safe state
>and don't need to worry about cleaning it up then you could just store it in a
>static variable which would be the simplest option.
>If you want to use Postgres's facilities for allocating memory and cleaning it
>up when no longer in use you can use some of the Postgres internal API for
>memory contexts and resource owners. But I don't see any particular reason you
>should need to worry about this stuff for something simple you're implementing
>yourself.
On 10/18/07, D'Arcy J.M. Cain <darcy@druid.net> wrote: On Thu, 18 Oct 2007 11:24:24 -0400
"Billow Gao" <billowgy@gmail.com> wrote:
> I can write the network program.
> But I am not 100% sure whether I can add the c-language function (
> http://www.postgresql.org/docs/8.2/interactive/xfunc-c.html)
> to PostgreSQL. The function will be dynamic loaded by PostgreSQL.
> I want to know whether there are any limitation on the function I wrote.
>
> for example:
> If I want to write a function:
>
> PG_FUNCTION_INFO_V1(c_talktoremoteudp);
>
>
> And use it in PostgreSQL like:
>
> =========================================
> SELECT name, c_talktoremoteudp
>
> (emp, 1500) AS overpaid
> FROM emp
> WHERE name = 'Bill' OR name = 'Sam';
>
> =========================================
> The function c_talktoremoteudp will:
> 1. send udp data to remote udp server
> 2. monitor an udp port and wait for the reply
> 3. return the data to the select query.
I am confused. The dynamic function resides in the server. The query
runs in the server. Where is the "remoteness" in any of this? Are you
saying that there is a second server that is not PostgreSQL that uses
UDP that you want to communicate with and merge info into the
PostgreSQL server from?
--
D'Arcy J.M. Cain <darcy@druid.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.
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