How does the Database Agent impact resource overhead?

[Christine.Chang]

The database agent can add between 0% to 2% additional overhead on CPU usage. In addition, a database's idle time may be reported as overhead; for example, if a database is idle for 99% of the time, it may look like the database has an overhead of close to 100%. The existing resource allocation for most databases can support the agent overhead, so you should not need to increase the resource allocation for the application when installing the agent. 

Queries that are run on SQL Server and Oracle may consume temporary storage if the data is large or if the database sort area size is small.