Oracle RAC Temp Tablespaces Test

A temporary tablespace, contrary to what the name might indicate, does exist on a permanent basis as do other tablespaces, such as the System and Sysaux tablespaces. However the data in a temporary tablespace is of a temporary nature, which persists only for the length of a user session. Oracle uses temporary tablespaces as work areas for tasks such as sort operations for users and sorting during index creation. Oracle does not allow users to create objects in a temporary tablespace. By definintion, the temporary tablespace holds data only for the duration of the user’s session, and the data can be shared by all users.

Sufficient free space should be available in the temporary tablespace, as critical operations such as sorting and execution of hash-intensive queries may otherwise fail. Periodically checking the space usage in the temporary tablespaces will provide you with early warning signals of potential space contentions. The RAC Temp Tablespaces test monitors the usage of the temporary tablespace in each instance of the Oracle RAC, and proactively reports which temporary tablespace is running dangerously low on free space. Moreover, the test also reports the usage of the temporary tablespace across instances.

Target of the test : Oracle RAC

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the temporary tablespace of each instance managed by the monitored Oracle RAC

Configurable parameters for the test
  1. TEST PERIOD - How often should the test be executed.
  2. Host – The host for which the test is to be configured.
  3. Port - The port on which the server is listening.
  4. orasid - The variable name of the oracle instance.
  5. 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’

  6. 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.

  7. Password – Password of the specified database user
  8. Confirm password – Confirm the password by retyping it here.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Used space:

Indicates the space used by this temporary tablespace.

MB

If this value is very high, then it indicates that the memory of this tablespace is almost full.

Free space:

Indicates the amount of unused space in this temporary tablespace.

MB

If this value is very low, then it indicates over-utilization of the tablespace.

Total space:

Indicates the total amount of space allocated for this temporary tablespace.

MB

 

Max space:

Indicates the maximum extent up to which this temporary tablespace can grow.

MB

Used percentage:

Indicates the percentage of space used in this temporary tablespace.

Percent

If this value is very high, then it indicates over-utilization of the tablespace.

Free percentage:

Indicates the space available for overall growth expressed as a ratio of Free space with respect to the Max space of this temporary tablespace. The formula used is: Free_space/Max_bytes*100

Percent

If this value is very low, it indicates that more space needs to be allotted to this tablespace to ensure that critical operations do not fail.