Note: Available for Oracle 10.2 and later.
The Services By Instance page summarizes the current load associated with the services deployed on the Oracle RAC cluster.
To open the Services By Instance page
Charts on the Services page
CPU shows the rate (in milliseconds per second) at which CPU time is consumed by each service for all sessions on the database. Among the services deployed are:
The aggregated CPU time for all services cannot exceed (1000 ms/s) x (the number of CPUs on the cluster).
DB Time shows the rate (in milliseconds per second) at which elapsed time is spent in database user calls by the specified services.
DB time includes all wait time, and does not have the same limitations as CPU time. Because in theory ALL sessions may be waiting at the same time, the aggregated DB Time for all services can be as much as (1000 ms/s) x (the number of sessions connected).
There will always be some sessions connected on each instance in the cluster — even before a user logs in.
Logical Reads shows the rate of logical reads for the specified services across the instances in the Oracle RAC cluster.
A logical read occurs when Oracle finds data in the local buffer cache of an instance without needing to read the data from physical disk. The rate of logical reads can be used to measure the balance between the instances in a cluster.
Physical Reads shows the rate of physical reads for the specified services across the instances in the Oracle RAC cluster.
A physical read occurs when a database instance retrieves data from datafiles on the shared disk subsystem, and occurs every time a logical read fails to find the requested page in local or global cache.
Actions on the Services Page
Use the Chart Orientation control to display each chart in one of two ways:
|Services by Instance||
|Instances by Service||