Oracle RAC Undo Usage Test

This test periodically monitors the space usage of UNDO tablespace of each instance managed by the Oracle cluster, and proactively alerts administrators to excessive space consumption by, or deficiencies in space allocations to, the UNDO tablespace.

Target of the test : Oracle RAC

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the undo 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. SCAN Name - SCAN stands for Single Client Access Name, it is a feature used in Oracle RAC environments that provide a single name for clients to access any Oracle Database running in the cluster. You can provide SCAN as an alternative to IP/Host Name. If this parameter value is provided, it will be used for connectivity otherwise IP/Hostname will be used.
  5. orasid - The variable name of the oracle instance.

  6. 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’

  7. 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.

  8. Password – Password of the specified database user
  9. Confirm password – Confirm the password by retyping it here.

  10. 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 only by a SYS user 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# ;

  11. SSL- By default, this flag is set to No, as the target Oracle cluster is not SSL-enabled by default. If the target cluster is SSL-enabled, then set this flag to Yes.
  12. SSL Cipher-This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none. A cipher suite is a set of cryptographic algorithms that are used before a client application and server exchange information over an SSL/TLS connection. It consist of sets of instructions on how to secure a network through SSL (Secure Sockets Layer) or TLS (Transport Layer Security). In this text box, provide a comma-seperated list of cipher suites that are allowed for SSL/TLS connection to the target cluster. By default, this parameter is set to none.
  13. TRUSTSTORE FILE- This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none. TrustStore is used to store certificates from Certified Authorities (CA) that verify and authenticate the certificate presented by the server in an SSL connection. Therefore, the eG agent should have access to the truststore where the certificates are stored to authenticate and connect with the target cluster and collect metrics. For this, first import the certificates into the following default location <eG_INSTALL_DIR>/lib/security/mytruststore.jks. To know how to import the certificate into the truststore, refer toPre-requisites for monitoring Oracle Cluster. Then, provide the truststore file name in this text box. For example: mytruststore.jks. By default, none is specified against this text box.
  14. TRUSTSTORE TYPE-This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none.Specify the type of truststore that contains the certificates for server authentication in this text box. For eg.,JKS. By default, this parameter is set to the value none.
  15. TRUSSTORE PASSWORD-This parameter is applicable only if the target Oracle Cluster is SSL-enabled, if not, set this parameter to none. If a Truststore File name is provided, then, in this text box, provide the password that is used to obtain the associated certificate details from the Truststore File. By default, this parameter is set to none.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Total space

Indicates the total size of the UNDO tablespace.

MB

 

Used space

Indicates the used size of the UNDO tablespace.

MB

 

Free space

Indicates the free size of the UNDO tablespace.

MB

Ideally, the value of this measurement should be very high.

Used percentage

Indicates the percentage of space allocated to the UNDO tablespace, which is already used.

Percent

Typically, a high percentage indicates that the available free space in this undo tablespace is very less. Therefore, to optimize this measure, the administrator is required to allocate sufficient space to this tablespace or tune the undo retention period and figure out the process that takes longer time to query the required data.