V$SES_OPTIMIZER_ENV

V$SES_OPTIMIZER_ENV displays the contents of the optimizer environment used by each session. When a new session is first created, it automatically inherits its optimizer environment from the optimizer environment defined at the instance level by V$SYS_OPTIMIZER_ENV. The value of certain parameters can be dynamically modified by issuing an ALTER SESSION statement.

Column	Datatype	Description
`SID`	`NUMBER`	Session identifier. This column can be used to join with `V$SESSION` on the `SID` column.
`ID`	`NUMBER`	Unique identifier of the parameter in the optimizer environment
`NAME`	`VARCHAR2(40)`	Name of the parameter
`SQL_FEATURE`	`VARCHAR2(64)`	Associated feature control ID
`ISDEFAULT`	`VARCHAR2(3)`	Indicates whether the parameter is set to the default value (`YES`) or not (`NO`)
`VALUE`	`VARCHAR2(25)`	Value of the parameter for the session
`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