Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Listener shows 2 instances per service?

Re: Listener shows 2 instances per service?

From: EdStevens <quetico_man_at_yahoo.com>
Date: 5 Jan 2007 06:22:59 -0800
Message-ID: <1168006979.917038.38020@11g2000cwr.googlegroups.com>

hpuxrac wrote:
> Alexander Skwar wrote:
> > Hello!
> >
> > I'm trying to understand what "lsnrctl" shows me and have a hard
> > time to grasp it.
> >
> > When I login as "oracle" OS user, I start the listener control utility
> > by running "lsnrctl". I then start the LISTENER by running "start" and
> > get:
> >
> > LSNRCTL> start
> > Starting /opt/apps/oracle/product/9.2.04/bin/tnslsnr: please wait...
> >
> > TNSLSNR for Solaris: Version 9.2.0.4.0 - Production
> > System parameter file is /opt/apps/oracle/product/9.2.04/network/admin/listener.ora
> > Log messages written to /opt/apps/oracle/product/9.2.04/network/log/listener.log
> > Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=winds06.win.ch.da.rtr)(PORT=1521)))
> >
> > Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=winds06.win.ch.da.rtr)(PORT=1521)))
> > STATUS of the LISTENER
> > ------------------------
> > Alias LISTENER
> > Version TNSLSNR for Solaris: Version 9.2.0.4.0 - Production
> > Start Date 05-JAN-2007 11:50:10
> > Uptime 0 days 0 hr. 0 min. 0 sec
> > Trace Level off
> > Security OFF
> > SNMP OFF
> > Listener Parameter File /opt/apps/oracle/product/9.2.04/network/admin/listener.ora
> > Listener Log File /opt/apps/oracle/product/9.2.04/network/log/listener.log
> > Listening Endpoints Summary...
> > (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=winds06.win.ch.da.rtr)(PORT=1521)))
> > Services Summary...
> > Service "RACE002" has 1 instance(s).
> > Instance "RACE002", status UNKNOWN, has 1 handler(s) for this service...
> > Service "RACEA1" has 1 instance(s).
> > Instance "RACEA1", status UNKNOWN, has 1 handler(s) for this service...
> > Service "RACEB1" has 1 instance(s).
> > Instance "RACEB1", status UNKNOWN, has 1 handler(s) for this service...
> > Service "RACEP1" has 1 instance(s).
> > Instance "RACEP1", status UNKNOWN, has 1 handler(s) for this service...
> > Service "RACEREF1" has 1 instance(s).
> > Instance "RACEREF1", status UNKNOWN, has 1 handler(s) for this service...
> > The command completed successfully
> >
> > So there's just 1 instance per service - fine!
> >
> > A few seconds later, I ran "status" and got:
> >
> > LSNRCTL> status
> > Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=winds06.win.ch.da.rtr)(PORT=1521)))
> > STATUS of the LISTENER
> > ------------------------
> > Alias LISTENER
> > Version TNSLSNR for Solaris: Version 9.2.0.4.0 - Production
> > Start Date 05-JAN-2007 11:50:10
> > Uptime 0 days 0 hr. 0 min. 44 sec
> > Trace Level off
> > Security OFF
> > SNMP OFF
> > Listener Parameter File /opt/apps/oracle/product/9.2.04/network/admin/listener.ora
> > Listener Log File /opt/apps/oracle/product/9.2.04/network/log/listener.log
> > Listening Endpoints Summary...
> > (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=winds06.win.ch.da.rtr)(PORT=1521)))
> > Services Summary...
> > Service "RACE002" has 2 instance(s).
> > Instance "RACE002", status UNKNOWN, has 1 handler(s) for this service...
> > Instance "RACE002", status READY, has 1 handler(s) for this service...
> > Service "RACEA1" has 2 instance(s).
> > Instance "RACEA1", status UNKNOWN, has 1 handler(s) for this service...
> > Instance "RACEA1", status READY, has 1 handler(s) for this service...
> > Service "RACEB1" has 2 instance(s).
> > Instance "RACEB1", status UNKNOWN, has 1 handler(s) for this service...
> > Instance "RACEB1", status READY, has 1 handler(s) for this service...
> > Service "RACEP1" has 2 instance(s).
> > Instance "RACEP1", status UNKNOWN, has 1 handler(s) for this service...
> > Instance "RACEP1", status READY, has 1 handler(s) for this service...
> > Service "RACEREF1" has 2 instance(s).
> > Instance "RACEREF1", status UNKNOWN, has 1 handler(s) for this service...
> > Instance "RACEREF1", status READY, has 1 handler(s) for this service...
> > The command completed successfully
> >
> > Hm. Why are there now 2 instances per service?
> >
> > I haven't set up the server or databases myself and am trying to understand
> > what the former admin did here. In the internal documentation I cannot
> > find anything reg. this and there's also just one database host here.
> >
> > It would be great if somebody could help me here.
> >
> > Thanks a lot,
>
> It's really not a problem. At some point oracle added "dynamic
> registration" to the startup of the oracle database instance so it
> would register itself with a local listener. ( I think it was 8i ? ).
>
> Many existing environments have a pre-configured listener.ora which
> also has ( one could say hard coded ) a list of the instances which the
> listener will support.
>
> This has the effect of double counting ... one entry from the static
> pre-configured information in the listener.ora and another one from
> when the oracle instance dynamically tells the listener about itself.
>
> I have never seen this to be involved in a problem ( but who knows,
> anyone got a story here ? ).
>
> It's a little unclear why the oracle code for the listener double
> counts instead of just says "ok thanks I already knew about you" but
> it's probably related to a static configuration that says "this
> instance might actually be running and you support it" versus the
> dynamic one that says "yes here I am and I am now running" or something
> like that.

That's the most newbie-friendly response/explanation of this I've seen.  You really should save that into a little text file and paste it back into responses to the near weekly repitition of this question. Received on Fri Jan 05 2007 - 08:22:59 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US