A temporary dbspace is a dbspace reserved exclusively for the storage of temporary tables. You cannot mirror a temporary dbspace.
The database server never drops a temporary dbspace unless it is explicitly directed to do so. A temporary dbspace is temporary only in the sense that the database server does not preserve any of the dbspace contents when the database server shuts down abnormally.
Whenever you set up the database server, all temporary dbspaces are set up. The database server clears any tables that might remain since the last time that the database server shut down.
The database server does not perform logical or physical logging for temporary dbspaces. Because temporary dbspaces are not physically logged, fewer checkpoints and I/O operations occur, which improves performance.
The database server logs table creation, the allocation of extents, and the dropping of the table for a temporary table in a standard dbspace. In contrast, the database server does not log tables stored in temporary dbspaces. Logical-log suppression in temporary dbspaces reduces the number of log records to roll forward during logical recovery as well, thus improving the performance during critical down time.
Using temporary dbspaces to store temporary tables also reduces the size of your storage-space backup, because the database server does not back up temporary dbspaces.
If you have more than one temporary dbspace and execute a SELECT statement into a temporary table, the results of the query are inserted in round robin order.
For detailed instructions on how to create a temporary dbspace, see Creating a Temporary Dbspace.