Re: Querying the hostname of the server

Yes, nice and simple.

I just did this in C and it works ok!

hostname.c
===========================================

#include <unistd.h>
#include "postgres.h"
#include "utils/elog.h"
#include "utils/palloc.h"
#include "storage/bufpage.h"
#define MAX_HOST_SIZE 200

PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(hostname);
Datum hostname(PG_FUNCTION_ARGS);

Datum
hostname(PG_FUNCTION_ARGS)
{
int len;
char buf[MAX_HOST_SIZE + 1];
text *result;

gethostname(buf,MAX_HOST_SIZE);
len = strlen(buf);
//elog(NOTICE, "hostname=%s\n",buf);
result=(text *)palloc(len + VARHDRSZ);
SET_VARSIZE(result, len + VARHDRSZ);
memcpy(VARDATA(result),buf,strlen(buf));
PG_RETURN_POINTER(result);
}

Makefile
===========================================
MODULE_big = hostname
OBJS = hostname.o

ifdef USE_PGXS
PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
include $(PGXS)
else
subdir = /var/lib/pgsql/src/Ccode/hostname
top_builddir = /usr/local/src/postgresql-8.3.3
include $(top_builddir)/src/Makefile.global
include $(top_srcdir)/contrib/contrib-global.mk
endif

hostname.sql
==================================================
CREATE OR REPLACE FUNCTION hostname() RETURNS text
AS '$libdir/hostname', 'hostname'
LANGUAGE c IMMUTABLE STRICT;

Στις Friday 30 April 2010 17:43:49 ο/η Glyn Astill έγραψε:
> --- On Fri, 30/4/10, Ross J. Reedstrom <reedstrm(at)rice(dot)edu> wrote:
>
> > > Hi,
> > >
> > > I have a number of PostgreSQL servers which I often
> > access through ssh
> > > tunnel with Pgadmin3. I would like to double check
> > which one I have landed
> > > on (if the tunnel is really configured the way I
> > want). Is there a way to
> > > query the hostname from the catalogs?
> >
> > Hmm, that's a bit tricky, since I assume you're using a
> > local db
> > connection inside the tunnel, so inet_server_addr()
> > probably returns
> > null. If you're talking unix/linux machines, then
> > /etc/hostname _should_
> > have the current hostname in it, so:
> >
> > create temp table foo (t text);
> > copy foo from '/etc/hostname';
> > select * from foo;
> > drop table foo;
> >
> > Should work.
> >
>
> Or you could do something like:
>
> CREATE OR REPLACE FUNCTION hostname()
> RETURNS text AS
> $BODY$
> $host = `hostname`;
> return $host;
> $BODY$
> LANGUAGE 'plperlu';
>
>
>
>
>
>

--
Achilleas Mantzios