Default Parameters for OraExtentsTest

An extent in Oracle is a set of contiguous blocks allocated in Oracle for storage of data. Since this is one of the basic units of allocation, proper management of extents is essential for efficient database performance. The OraExtentsTest helps in identifying objects that are running out of extents and those that are using too many extents.

Note:

This test is applicable only for Oracle databases with ‘Dictionary Managed Tablespace’. From Oracle 9i onwards, all tablespaces are ‘Locally Managed Tablespaces’. Therefore, this test is applicable only upto Oracle 8i.

This page depicts the default parameters that need to be configured for the OraExtentsTest.

• The TEST PERIOD list box helps the user to decide how often this test needs to be executed. 

• 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 in the USER text box, and the password of this user has to be entered in the PASSWORD text box. Confirm the password by retyping it in the CONFIRM PASSWORD text box. 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.

• 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# ;
  

• This test reports a Large_extent_objects measure, which reveals the number of objects that exceed a pre-configured number of extents; this limit is set using the MAXEXTENT parameter. If you enter a number in the MAXEXTENT text box, then, the Large_extent_objects measure of this test will return the count of objects with more extents than the number specified in the MAXEXTENT text box. By default, the MAXEXTENT parameter is set to 1000.

• If the ISPASSIVE parameter is set to YES, then it means that, by default, all Oracle servers being monitored by the eG system are the passive servers of an Oracle cluster. No alerts will be generated if the servers are not running. Measures will be reported as "Not applicable" by the agent if the servers are not up.

• Once the necessary values have been entered, clicking on the UPDATE button will register the changes made.

When changing default configurations of tests, the values with "$" indicate variables that will be replaced by the eG system according to the specific server being managed - for instance, $hostName is the host/nickname of the target host, $port is the port number of the server being monitored. E.g., for a server xyz:80, $hostName will be changed automatically by the eG manager to "xyz" and $port will be changed to "80" when configuring a test.