OneDB 
SAP liveCache OneDB (OneDB) is the combination of an SAP MaxDB database with an SAP liveCache database within a database.
SAP liveCache OneDB has many advantages over a normal configuration with two separate database instances, including:
You only have to maintain one database.
The SAP MaxDB and SAP liveCache databases share resources such as the data cache, CPU, log volumes, data volumes, and backups.
Activities
It is sufficient to perform the usual database administration tasks for only the SAP MaxDB database of your OneDB. For the SAP liveCache database of your OneDB, you need only to take account of the following:
Ensure regularly that the SQL Optimizer statistics for the SAP liveCache database of your OneDB are up-to-date. Use the Optimizer Statistics node in the liveCache Alert Monitor to do this. If necessary, schedule an update of the SQL Optimizer statistics (DBA Planning Calendar, Scheduling an Update of the SQL Optimizer Statistics).
Explicitly starting/stopping the SAP liveCache database of a OneDB is not required and not desirable. Therefore, the functions Start liveCache and Stop liveCache in the Operating user menu (DBA Cockpit/liveCache Assistant) cannot be used. The function modules START_LIVECACHE_LVC and STOP_LIVECACHE_LVC are also not available for the SAP liveCache database of a OneDB (Function Module for Starting/Stopping/Initializing).
More Information
SAP Note 1038709 (FAQ: SAP MaxDB/liveCache One DB)