Oracle Transactions Test

Rollbacks are costly operations on the database. This test monitors the percentage of rollbacks happening for user transactions with a database instance.

This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick Oracle Database as the Component type, Performance as the Test type, choose this test from the disabled tests list, and click on the << button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Target of the test : An Oracle server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every SID monitored.

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. 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.

  5. Password – Password of the specified database user

    This login information is required to query Oracle’s internal dynamic views, so as to fetch the current status / health of the various database components.

  6. Confirm password – Confirm the password by retyping it here.
  7. ISPASSIVE – If the value chosen is yes, then the Oracle server under consideration is a passive server in an Oracle cluster. No alerts will be generated if the server is not running. Measures will be reported as “Not applicable" by the agent if the server is not up.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

User commits:

The number of user commits that have happened during the last measurement period

Number

 

User rollbacks:

The number of user rollbacks that have happened during the last measurement period

Number

Ideally, there should be few user rollbacks happening.

Typically, whenever a delete, insert or update operation is performed on the database, Undo tablespace is consumed, I/O overheads increase, and considerable server time is spent in performing that operation. When such operations are rolledback, these resources are wasted! To conserve resources, its best to keep rollbacks at a minimum. 

Percent rollbacks:

The number of user rollbacks as a percentage of the total user transactions (user commits + user rollbacks) with the database

Percent

The closer the percentage of rollbacks is to zero, the lower the overhead on the database due to rollbacks. The acceptable value of rollbacks will vary from one instance to another and will have to be configured based on the patterns of requests being handled by the database instance.