Usually, I configure and run multiple listeners listening at different ports, for the production database. For some important instances like PILOT and TRAINING also I configure multiple listeners, depending on criticality of the instance maintained.

You can configure different listener service in different ports for different purposes. One listener for process schedulers and one listener for external app servers and one listener for internal app servers and more importantly one listener for your maintenance purpose. I do not disclose the port numbers to others which I use for maintenance for obvious reasons.

Also you can configure the specific port numbers to a network card so that the traffic is divided if you have high traffic and heavy usage like CRM.

If you are experienced DBA, you should not have much difficulty in configuring multiple listeners.

If you need more information on how to configure multiple listener or configuring a port to a specific network card [needs root access],  I would be glad to help, just leave a note here.

One final note: Don’t forget to secure the listeners, especially if you are using older versions.

If you are new DBA, read this security document by Integrigy on listeners’ security. It has good information.

Comments (9)

	1. 03-05-2008 09:42
	I don't understand how multiple listeners are useful, especially if we are on 1 RAC. Do they allow access to different objects, or provide different resources? Guest

JustMe

	2. 03-06-2008 07:42
	No the listeners will not restrict access to different objects. If you want to restrict to objects, then you may create different user ids and restrict the access. This article is to emphasis on the security and control the access of the database from different applications like app server and process scheduler. http://psadmin.org Registered

RD

	3. 10-13-2008 09:42
	1) Is there a performance benefit for setting up multiple listeners?    2) If I have multiple listeners, how do I measure Listener response time ? Anything captured within the database? Guest

ML

	4. 10-13-2008 10:18
	There is some performance benefit indirectly. Creating multiple listeners does not improve the performance of listeners in general as the response time on any query depends on various factors like network bandwidth etc.  But it will improve in other way like it distributes the load on the listeners. For example if you are running an application for customers, agent and executives in different box and you want to the performance on the executives not disturbed, then you can create separate listeners for separate different applications and keep the executive application separately and not disturbed by other listeners which has high traffic like customers and agents. Configure the listener which is assigned to executive application through higher bandwidth or you might connect the boxes directly without going through the regular network by using fiber cords etc. http://www.psadmin.org Registered

RD

	5. 10-13-2008 11:39
	Thanks for your response.    In other words, what would be the various reasons I may want to create additional listener, other than management purpose (explained above). Is there something like, it is X secs response/wait time on my default listener and adding a 2nd listener would help me bring down the X secs. Is there some metric to measure/quantify the performance of a listener ? Guest

ML

	6. 10-13-2008 12:40
	Yes, it should not make any difference if the listeners are going through same IP/network Cord and the query is the same with the idealistic conditions like no lock on the objects, load on the traffic are the same etc. http://www.psadmin.org Registered

RD

	7. 10-14-2008 06:29
	OK, Thanks much.     So, in conclusion, what I hear is that there is no way to determine how well your listener is performing/handling load (a decision point to add additional listeners).    Thanks again. Guest

ML

	8. 10-14-2008 07:06
	Yes.     The listeners do not increase or reduce performance. Only other factors like network, bandwidth, structure of the query, memory on the server allocated to SGA etc change the performance. When you have multiple Listeners you are dividing the load between two different networks. http://www.psadmin.org Registered

RD

	9. 10-14-2008 11:45
	Thanks much Guest

ML

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