What is the significance of remote listener in rac

Using multiple addresses allows a client to connect to an instance of the database even if the initial instance has failed. Oracle RAC provides failover with the node VIP addresses by configuring multiple listeners on multiple nodes to manage client connection requests for the same database service. If a node fails, then the service connecting to the VIP is relocated transparently to a surviving node, enabling fast notification of the failure to the clients connecting through the VIP.

If the application and client are configured with transparent application failover options, then the client is reconnected to the surviving node. Standalone Oracle databases perform load balancing by distributing connections among the shared server dispatcher processes.

Oracle RAC uses both dedicated and shared server processing when shared servers are configured. The installation process creates a tnsnames. This file acts as a repository of net service names. Each net service name is associated with a connect identifier. A connect identifier is an identifier that maps a user-defined name to a connect descriptor.

A connect descriptor contains the following information:. The network route to the service, including the location of the listener through a protocol address. The tnsnames. By default, the tnsnames. With Oracle Clusterware 11 g Release 2 and later, the listener association no longer requires tnsnames. The listener associations are configured as follows:. For example, after you create the database, to add a second listener, listening on port , use a command similar to the following command to have the database register with both listeners on startup:.

DBCA creates net service names for connections as described in the following sections:. You can also use net service names to connect to Oracle RAC. This example shows a connect descriptor that is used in a tnsnames. The connect identifier in this case is the same as the cluster domain, mycluster. Instead of specifying the address for an individual server, virtual Internet Protocol VIP address, or a cluster node name, the connect descriptor uses the SCAN, which is myscan.

Oracle Clusterware resolves connection requests that use the net service name mycluster. The specific cluster node on which the instance is running is invisible to the client.

The net service name does not require a fully qualified domain name for the server on which a database, database instance, or listener runs. The client then submits connection requests to each address in succession until a connection is made. Clients that connect to a particular instance of the database use the net service name for the instance. In this example, the connect identifier is the same as the instance name, mycluster1. The connect descriptor uses the SCAN to locate the instance within the cluster.

Clients connecting to the net service name mycluster1. Oracle Clusterware resolves that connection to the cluster node on which the instance is running.

The following sections describe Oracle Net listener configuration:. The listener. If needed, you can edit the listener. Do not modify the endpoints because these are automatically managed by the listener agent. Oracle recommends that you leave the parameter unset so that the Database Agent process can maintain it automatically.

Oracle Database Net Services Reference for more information about the listener. Oracle Database Net Services Administrator's Guide for information about understanding and configuring listeners. A remote listener is a listener residing on one computer that redirects connections to a database instance on another computer. For example, SCAN listeners are remote listeners. Oracle Database Net Services Reference for an overview of listeners.

To administer Oracle Database 12 c Release 1 Do not attempt to use the lsnrctl commands from Oracle home locations for earlier releases, because they cannot be used with Oracle Database 12 c Release 1 For listeners not managed by Oracle Clusterware, you can use a non-default location for the listener.

It can include the protocol addresses it is accepting connection requests on, a list of the database and other services it is listening for, and control parameters used by the listener. Manual editing of the listener. Each listener is configured with one or more protocol addresses that specify its listening endpoints. The listener agent dynamically updates endpoints with the listener. Starting with Oracle Database 11 g Release 2, the listener. Listening endpoints, such as the port numbers, are dynamically registered with the listener.

The listener is configured with default protocol listening addresses. How is a scan listener different from a regular database listener? What makes a SCAN listener special? Unlike a regular listener where the listener is accessed via a DNS host name or IP address , a SCAN listener uses a list of domain names, allowing Oracle to assign incoming connections to a server using their own least-recently-used algorithm.

If listener know from advisories that its local instance is least loaded and should service client request then listener passes client request to local instance. If local instance is over loaded then listener can use TNS redirect to redirect client request to a less loaded instance means remote instance.

This is called as Server Side Load balancing. Facebook Page: OracleHelp. Latest posts by Ludovico see all. Beware of how it registers. Seems it is oracle bug. Leave a Reply Cancel reply Your email address will not be published. This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Close Privacy Overview This website uses cookies to improve your experience while you navigate through the website.