V$PARAMETER

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>