Oracle RAC Active Sessions Test
This test reports the number of sessions currently active on each database in the Oracle RAC, and thus points you to overloaded instances.
Target of the test : Oracle RAC
Agent deploying the test : An internal agent
Outputs of the test : One set of results for every instance monitored.
Configurable parameters for the test
- TEST PERIOD - How often should the test be executed.
- Host – The host for which the test is to be configured.
- Port - The port on which the server is listening.
- orasid - The variable name of the oracle instance.
service name - A ServiceName exists for the entire Oracle RAC system. When clients connect to an Oracle cluster using the ServiceName, then the cluster routes the request to any available database instance in the cluster. By default, the service name is set to none. In this case, the test connects to the cluster using the orasid and pulls out the metrics from that database instance which corresponds to that orasid. If a valid service name is specified instead, then, the test will connect to the cluster using that service name, and will be able to pull out metrics from any available database instance in the cluster.
To know the ServiceName of a cluster, execute the following query on any node in the target cluster:
select name, value from v$parameter where name =’service_names’
User – In order to monitor an Oracle database server, a special database user account has to be created in every Oracle database instance that requires monitoring. A Click here hyperlink is available in the test configuration page, using which a new oracle database user can be created. Alternatively, you can manually create the special database user. When doing so, ensure that this user is vested with the select_catalog_role and create session privileges.
The sample script we recommend for user creation (in Oracle database server versions before 12c) for eG monitoring is:
create user oraeg identified by oraeg ;
create role oratest;
grant create session to oratest;
grant select_catalog_role to oratest;
grant oratest to oraeg;
The sample script we recommend for user creation (in Oracle database server 12c) for eG monitoring is:
alter session set container=<Oracle_service_name>;
create user <user_name>identified by <user_password> container=current default tablespace <name_of_default_tablespace> temporary tablespace <name_of_temporary_tablespace>;
Grant create session to <user_name>;
Grant select_catalog_role to <user_name>;
The name of this user has to be specified here.
- Password – Password of the specified database user
- Confirm password – Confirm the password by retyping it here.
To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.
The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:
- The eG manager license should allow the detailed diagnosis capability
- Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Number of sessions:
Indicates the number of sessions currently active on this instance.
This measure is a good indicator of the session load on an instance. Comparing the value of this measure across instances will help you identify the overloaded instance and also shed light on load-balancing irregularities.
You can use the detailed diagnosis of this measure to view the details of the active sessions. With the help of these details, you can figure out whether a session has remained open for too long a time due to prolonged wait events.