9.109 V$PARAMETER

V$PARAMETER displays information about the initialization parameters that are currently in effect for the session. A new session inherits parameter values from the instance-wide values displayed by the V$SYSTEM_PARAMETER view.
Column Datatype Description

NUM

NUMBER

Parameter number

NAME

VARCHAR2(80)

Name of the parameter

TYPE

NUMBER

Parameter type:

  • 1 - Boolean

  • 2 - String

  • 3 - Integer

  • 4 - Parameter file

  • 5 - Reserved

  • 6 - Big integer

VALUE

VARCHAR2(4000)

Parameter value for the session (if modified within the session); otherwise, the instance-wide parameter value

DISPLAY_VALUE

VARCHAR2(4000)

Parameter value in a user-friendly format. For example, if the VALUE column shows the value 262144 for a big integer parameter, then the DISPLAY_VALUE column will show the value 256K.

DEFAULT_VALUE

VARCHAR2(255)

The default value for this parameter. This is the value of the parameter if a value is not explicitly specified for the parameter.

ISDEFAULT

VARCHAR2(9)

Indicates whether the parameter is set to the default value (TRUE) or the parameter value was specified in the parameter file (FALSE).

The database sets the value of the ISDEFAULT column to TRUE for parameters that are not specified in the init.ora or server parameter file (SPFILE).

ISSES_MODIFIABLE

VARCHAR2(5)

Indicates whether the parameter can be changed with ALTER SESSION (TRUE) or not (FALSE)

ISSYS_MODIFIABLE

VARCHAR2(9)

Indicates whether the parameter can be changed with ALTER SYSTEM and when the change takes effect:

  • IMMEDIATE - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect immediately.

  • DEFERRED - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect in subsequent sessions.

  • FALSE - Parameter cannot be changed with ALTER SYSTEM unless a server parameter file was used to start the instance. The change takes effect in subsequent instances.

ISPDB_MODIFIABLE

VARCHAR2(5)

Indicates whether the parameter can be modified inside a PDB (TRUE) or not (FALSE)

ISINSTANCE_MODIFIABLE

VARCHAR2(5)

For parameters that can be changed with ALTER SYSTEM, indicates whether the value of the parameter can be different for every instance (TRUE) or whether the parameter must have the same value for all Real Application Clusters instances (FALSE). If the ISSYS_MODIFIABLE column is FALSE, then this column is always FALSE.

ISMODIFIED

VARCHAR2(10)

Indicates whether the parameter has been modified after instance startup:

  • MODIFIED - Parameter has been modified with ALTER SESSION

  • SYSTEM_MOD - Parameter has been modified with ALTER SYSTEM (which causes all the currently logged in sessions' values to be modified)

  • FALSE - Parameter has not been modified after instance startup

ISADJUSTED

VARCHAR2(5)

Indicates whether Oracle adjusted the input value to a more suitable value (for example, the parameter value should be prime, but the user input a non-prime number, so Oracle adjusted the value to the next prime number)

ISDEPRECATED

VARCHAR2(5)

Indicates whether the parameter has been deprecated (TRUE) or not (FALSE)

ISBASIC

VARCHAR2(5)

Indicates whether the parameter is a basic parameter (TRUE) or not (FALSE)

DESCRIPTION

VARCHAR2(255)

Description of the parameter

UPDATE_COMMENT

VARCHAR2(255)

Comments associated with the most recent update

HASH

NUMBER

Hash value for the parameter name

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

Examples

The following query returns the default value for the ALLOW_GLOBAL_DBLINKS initialization parameter:

SQL> SELECT name, default_value FROM v$parameter
  2  WHERE name = 'allow_global_dblinks';

NAME
-----------------------------------------------------------
DEFAULT_VALUE
----------------------------------------------------------- 
allow_global_dblinks
FALSE


SQL>

The following query shows that the ALLOW_GLOBAL_DBLINKS initialization parameter is not modifiable in a PDB:

SQL> SELECT name, ispdb_modifiable FROM v$parameter
  2  WHERE name = 'allow_global_dblinks';

NAME
-----------------------------------------------------------
ISPDB
-----
allow_global_dblinks
FALSE


SQL>

See Also:

"V$SYSTEM_PARAMETER"