5.3 Viewing and Modifying Initialization Parameters

This section provides instructions about viewing the initialization parameter settings for your database and modifying these parameters. You can modify the initialization parameters for the database in one of three ways:

  • Until the instance is shut down: The new values for the initialization parameters are applied to the currently running instance, but, when the database is restarted, the initialization parameter values revert to their previous settings.

  • From now until the initialization parameter is changed again: The changes are applied to the currently running instance and are also stored in the server parameter file. The changes made to the initialization parameters persist when the database is restarted.

  • When the database is restarted: The new values for the initialization parameters are recorded in server parameter file, but are not applied to the currently running instance. The changes take effect only when the database is restarted.

Note:

These three scenarios correspond to using the SCOPE=MEMORY, SCOPE=BOTH, and SCOPE=SPFILE clauses of the ALTER SYSTEM SQL statement, respectively, when you use the ALTER SYSTEM statement to change initialization parameters.

To view or modify initialization parameters:

  1. In Oracle Enterprise Manager Database Express (EM Express), from the Configuration menu, select Initialization Parameters.

    The Initialization Parameters page appears.

    The Initialization Parameters page has two tabs:

    • Current—This tab (the default) displays all initialization parameter values that are currently active (in memory) for the Oracle instance.

    • SPFile—This tab displays initialization parameter settings in the server parameter file (SPFILE). This tab is present only when the current instance started up with a server parameter file. The file location is displayed at the top of the tab.

      Note:

      In a pluggable database (PDB), the Initialization Parameters page includes the PDB Modifiable column. Each initialization parameter that can be modified at the PDB level has a check mark in the PDB Modifiable column.

      Any initialization parameter in a PDB that does not have a check mark in the PDB Modifiable column can be set and modified only in the root, and the value set in the root applies to the individual PDBs in the multitenant container database (CDB).

    For more information on individual initialization parameters, see Oracle Database Reference.

  2. (Optional) On either tab, reduce the number of initialization parameters displayed by doing one or both of the following:

    • In the search field, enter text.

    • Select either the Modified or Basic option next to the search field to limit the display to either modified or basic initialization parameters.

    For example, to view only initialization parameters that have the text DEST anywhere in the parameter name, enter dest in the Search field. EM Express then restricts the list of initialization parameters accordingly.

  3. To modify an initialization parameter for the currently running instance only (the modifications will not persist when the instance is restarted), complete the following steps:

    1. On the Current tab, select the initialization parameter whose value you want to modify.

      Note:

      If the Set button does not become available when you select the parameter, then the parameter is not dynamic—that is, it cannot be changed for the current instance.

    2. Click the Set button.

      The Set Initialization Parameter page appears.

    3. In the Value column, enter a new value for the initialization parameter.

    4. For the Scope field, ensure that Memory is selected. The value you set will not persist when the instance is restarted.

    5. (Optional) In the Comments column, enter text explaining the reasons for the changes.

    6. Click OK.

      A confirmation message appears.

  4. To modify an initialization parameter for the currently running instance, and also record the modifications in the server parameter file that will persist when the database instance is restarted, complete the following steps:

    1. On the Current tab, select the initialization parameter whose value you want to modify.

      Note:

      If the Set button does not become available when you select the parameter, then the parameter is not dynamic—that is, it cannot be changed for the current instance.

    2. Click the Set button.

      The Set Initialization Parameter page appears.

    3. For the Scope field, ensure that both Memory and SPFile are selected. The value you set will persist when the database instance is restarted.

      Note:

      If the SPFile option is not available, then the database instance does not have an SPFILE, and changes made to the instance will not persist when the instance is restarted.

    4. (Optional) In the Comments column, enter text explaining the reasons for the changes.

    5. Click OK.

      A confirmation message appears. The message includes a Show SQL button. Click the Show SQL button to see the SQL statement that was executed.

  5. To modify an initialization parameter in the server parameter file only, such that the current instance is not affected and changes take effect only when the database is next restarted, complete the following steps:

    1. Click SPFile to view the SPFile tab.

    2. Select the initialization parameter whose value you want to modify. If the initialization parameter does not appear on the SPFile tab, then select the initialization parameter on the Current tab, instead.

    3. Click the Set button.

      The Set Initialization Parameter page appears.

    4. In the Scope field, choose SPFile.

      For an initialization parameter that cannot be reset without restarting the database, the Scope field defaults to SPFile, and the Memory option does not appear.

    5. In the Value column, enter a new value for the initialization parameter.

    6. (Optional) In the Comments column, enter text explaining the reasons for the changes.

    7. Click Apply.

      A confirmation message appears.

Note:

Changes to initialization parameters are recorded in the alert log as ALTER SYSTEM statements. See Oracle Database Administrator's Guide for information about the alert log.