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Re: Listener shows 2 instances per service?

From: hpuxrac <johnbhurley_at_sbcglobal.net>
Date: 5 Jan 2007 05:40:53 -0800
Message-ID: <1168004453.330654.160500@s80g2000cwa.googlegroups.com>

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. Received on Fri Jan 05 2007 - 07:40:53 CST

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