Prior to K2 blackpearl 4.6, multiple databases on the same SQL instance were created during the installation of K2 blackpearl.
With clean installs of 4.6 and later, a single database is created. If previous versions are upgraded to 4.6 or later, the multiple databases are upgraded but not consolidated.
Maintaining a Single consolidated K2 database is much easy. We strongly recommend our clients to consolidate.
The K2 Database Consolidation Tool is used to consolidate multiple K2 databases into a single database.
Please contact K2 Support in order to receive the correct version of the K2 Database Consolidation Tool for your environment.
More information on the tool can be obtained here on this KB – http://help.k2.com/kb001628