This command swaps two Redis databases, so that immediately all the clients connected to a given database will see the data of the other database, and the other way around. Example:
SWAPDB 0 1
This will swap database 0 with database 1. All the clients connected with database 0 will immediately see the new data, exactly like all the clients connected with database 1 will see the data that was formerly of database 0.
ERR Unknown or disabled command 'SWAPDB'