Oracle DataFile Growth Test

Periodic monitoring of the usage of the database is essential to ensure that the database is always adequately sized to handle current and future loads. This test monitors the usage of the datafiles that underlie a managed Oracle database instance, and indicates if any of the datafiles require resizing.

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 datafile 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. alternate view – In large environments, where the volume of transactions to the Oracle database server is generally very high, this test may take time to execute and retrieve the desired results. To ensure that the test is faster and is resource-efficient, administrators of such environments can create an alternate ‘view’ on the target Oracle database server, and grant select privileges to the view to the special database user mentioned above. Once the view is created, the test should be configured to use the alternate view for metrics collection; to achieve this, specify the name of the view in the alternate view text box. By default, this text box is set to none, which implies that the alternate view is not used by default.

    This alternate ‘view’ should be created with the following structure:

    CREATE OR REPLACE VIEW <VIEW_NAME> (
    TABLESPACE_NAME,
    FILE_ID,
    BLOCK_ID,
    BYTES,
    BLOCKS,
    RELATIVE_FNO
    ) AS
    select /*+ use_hash (tsfi, fet2) */ tsfi.tablespace_name,
           tsfi.file_id,
           fet2.block_id,
           tsfi.blocksize * fet2.blocks,
           fet2.blocks,
           tsfi.relfile#
    from   (select /*+ use_hash (ts, fi) */ ts.name tablespace_name,
                   fi.file# file_id,
                   ts.BLOCKSIZE,
                   fi.relfile#,
                   ts.ts#
            from   sys.ts$ ts,
                   sys.file$ fi
            where  ts.ts# = fi.ts#
            and    ts.online$ in (1,4)) Tsfi,
           (select f.block# block_id,
                   f.length blocks,
                   f.file# file_id,
                   f.ts#
            from   sys.fet$ f
            union all
            select f.ktfbfebno block_id,
                   f.ktfbfeblks blocks,
                   f.ktfbfefno,
                   ktfbfetsn
            from   sys.x$ktfbfe f) Fet2
    where  fet2.file_id = tsfi.relfile#
    and    fet2.ts# = tsfi.ts# ;

  8. 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

Datafile size:

Indicates the current size of this datafile.

MB

 

Used space in datafile:

Indicates the amount of database space that has been currently utilized by this datafile.

MB

 

Free space in datafile:

Indicates the amount of free space currently available for this datafile.

MB

 

Space usage:

Indicates the percentage of database space that has been utilized by this datafile.

Percent

Ideally, this value should be low. A value close to 100% is a cause for concern.

Space free:

Indicates the percentage of free space for this datafile.

Percent

Ideally, this value should be high. A sudden/consistent decrease in the value of this measure could indicate excessive utilization of the database caused by a sporadic/steady increase in database activity. Very low free space for a datafile could significantly deteriorate database performance. Under such circumstances therefore, you might want to resize that particular datafile or reorganize all the datafiles that are present in the managed database instance.