Administration : Undo stores in Temporary tablespace?

Yes for for Temporary Tables.

Here is the excerpt from the documentation:-

By default, undo records for temporary tables are stored in the undo tablespace and are logged in the redo, which is the same way undo is managed for persistent tables. However, you can use the TEMP_UNDO_ENABLED initialization parameter to separate undo for temporary tables from undo for persistent tables. When this parameter is set to TRUE, the undo for temporary tables is called temporary undo.

Benefits

	Temporary undo reduces the amount of undo stored in the undo tablespaces.

	Less undo in the undo tablespaces can result in more realistic undo retention period requirements for undo records.
	Temporary undo reduces the size of the redo log.

	Performance is improved because less data is written to the redo log, and components that parse redo log records, such as LogMiner, perform better because there is less redo data to parse.

	Temporary undo enables data manipulation language (DML) operations on temporary tables in a physical standby database with the Oracle Active Data Guard option. However, data definition language (DDL) operations that create temporary tables must be issued on the primary database.

You can enable temporary undo for a specific session or for the whole system

Set the TEMP_UNDO_ENABLED initialization parameter:

	To enable temporary undo for a session, run the following SQL statement:
	ALTER SESSION SET TEMP_UNDO_ENABLED = TRUE;



	To disable temporary undo for a session, run the following SQL statement:
	ALTER SESSION SET TEMP_UNDO_ENABLED = FALSE;


	To enable temporary undo for the system, run the following SQL statement:
	ALTER SYSTEM SET TEMP_UNDO_ENABLED = TRUE;

	After temporary undo is enabled for the system, a session can disable temporary undo using the ALTER SESSION statement.


	To disable temporary undo for the system, run the following SQL statement:
	ALTER SYSTEM SET TEMP_UNDO_ENABLED = FALSE;

After temporary undo is disabled for the system, a session can enable temporary undo using the ALTER SESSION statement.

Note: By default the temporary undo is enabled for dataguard

Views:- V$TEMPUNDOSTAT,