Re: 2 instances, 1 listener, services summary

yls177 wrote:
> i have an oracle user who has 2 instances and they have the same
> oracle home from "env". Therefore, 2 instances are having the same
> listener, tnsnames configuration.
>
> Of course, the initsid.ora are different.
>
>
> LISTENER =
> (DESCRIPTION_LIST =
> (DESCRIPTION =
> (ADDRESS_LIST =
> (ADDRESS = (PROTOCOL = TCP)(HOST = myhost)(PORT = 1521))
> )
> )
> )
>
> SID_LIST_LISTENER =
> (SID_LIST =
> (SID_DESC =
> (GLOBAL_DBNAME = instance_1)
> (ORACLE_HOME = /oracle/product/8.1.7)
> (SID_NAME = idea)
> )
> )
>
> 1) status of lisenter gives the below
> Services Summary...
> instance_1 has 2 service handler(s)
> instance_2 has 2 service handler(s)
> instance_1 has 1 service handler(s)
> instance_1 has 2 service handler(s)
> instance_1 has 2 service handler(s)
> instance_2 has 2 service handler(s)
> instance_2 has 2 service handler(s)

Don't edit. If you want people to make intelligent comments about what you are experiencing, they need ALL the information, not your precis of it.

This extract in particular gives me no information. I cannot see whether some of these lines are referring to dispatchers or not. Whether some really refer to instances and not services or not. Whether some lines read STATUS READY and others STATUS UNKNOWN or not. And so on.

> a) both instances has the same port number.

Instances don't have port numbers. Be precise. You have one listener, running on port 1521. Fine. Perfectly normal and acceptable.

> b) in my listener configuration, i have only the instance_1
> configuration.

Yes, you have a static SID_LIST declaration of the fact that instance_1 exists. That should result in a line in lsnrctl status (or lsnrctl services) which states

"service instance_1 has 2 instances...

    Instance "instance_1", status UNKNOWN..."

...because you've merely said "Listen out for this SID", but the poor listener has no idea whether it is actually running.

You should also have a line saying :

    Instance "instance_1", status READY..."

Because in 8i and above, instances register their actual existence with the listener, using PMON, so that the listener knows very well that the specific instance is up and running and available for connections.

It is perfectly normal to have two instances listed for one service, provided one says READY and one UNKNOWN. It simply means the listener is aware of instances via two mechanisms -one where you tell it in the SID_LIST, the other where PMON tells it.

> c) both instances share the same oracle user

Not an issue.

> Questions
> i) I am puzzled by the list of services summary as shown above.What
> does it mean?

Who can say? Because you didn't cut and paste, but decided to do an edit job, and in the process stripped out all the relevant information!

> ii) in my listener configuration, i have only the entry for instance
> 1. And i have checked that when i su to the oracle user , the instance
> is instance_1.

That's not a question! What's the question? Your listener.ora doesn't mention instance_2, true enough. Yet your lsnrctl status command reports on instance_2. Is the question, 'how come it manages to do so'? Then the answer is: PMON registered the existence of instance_2 with the listener at startup. For instance_2, in other words, you only have one of the listener notification mechanisms in place: dynamic instance registration. You have chosen not to mention instance_2 in the SID_LIST section of the listener.ora, and therefore that mechanism is not in use. That is also perfectly acceptable (though it will mean that you'll never be able to manage instance_2 using Enterprise Manager, because the Intelligent Agent will not be aware of its existence... the Intelligent Agent relies on the SID_LIST section of the listener.ora to work out what instances are available for managing).

Incidentally, I notice that your global database name is INSTANCE_1. If that is correct, it means you haven't created your databases properly. If you're using the database configuration assistant, read the relevant naming screen carefully: it spells it out that the global database name should be in the form INSTANCE -dot- DOMAIN. And if you haven't got a real domain, invent one. Your global database name should have been, therefore, instance_1.local or instance_1.nodomain or instance_1.mydomain.com... anything at all, but not just the same thing as the instance name.

Because you didn't specify a domain name component of your global database name, you may well find that the actual global database name reported to the listener is 'instance_1.world'. "World" is what you get in 8i when you don't specify a domain of your own, IIRC.

Regards
HJR Received on Sun Nov 21 2004 - 21:45:17 CST