eG Monitoring
 

Measures reported by OraSessionTest

In the database context, the connection between the user process and the server process is called a session. The server process communicates with the connected user process and performs tasks on behalf of the users.

The OraSessionTest is used by an eG agent to track session related user activity corresponding to a database server instance.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Num_total_sessions Indicates the total number of users connected to the database server. Number A high value may indicate that there is a high load on the server. The detailed diagnosis capability, if enabled, lists all the current sessions of a user.
Num_active_sessions Indicates the number of sessions that are currently accessing the database. Number A high value may indicate that there is a high load on the server. The detailed diagnosis capability, if enabled, lists all the active sessions of a user.
Num_background_sessions Indicates the number of sessions that are created when the database starts. Number A high value may indicate that there is a high load on the server. The detailed diagnosis capability, if enabled, lists all the background sessions.
Num_blocked_sessions Indicates the number of sessions that were blocked in this database. Number Blocking occurs when one session holds a lock on a resource that another session is requesting. As a result, the requesting session will be blocked - it will hang until the holding session gives up the locked resource. In almost every case, blocking is avoidable. In fact, if you find that your session is blocked in an interactive application, then you have probably been suffering from the lost update bug as well, perhaps without realizing it. That is, your application logic is flawed and that is the cause of blocking.

The five common DML statements that will block in the database are INSERT, UPDATE, DELETE, MERGE and SELECT FOR UPDATE.

Ideally, the value of this measure should be zero. The detailed diagnosis capability, if enabled, lists all the blocked sessions of this database.
Num_cached_sessions Indicates the number of sessions that were temporarily cached for use by this database. Number A high value may indicate that there is a high load on the server. The detailed diagnosis capability, if enabled, lists all the cached sessions of this database.
Num_inactive_sessions Indicates the number of sessions that were inactive in this database. Number Ideally, the value of this measure should be zero. The detailed diagnosis capability, if enabled, lists all the inactive sessions in this database.
Num_killed_sessions Indicates the number of inactive sessions that were terminated in this database. Number When a session is terminated, any active transactions of the session are rolled back, and resources held by the session (such as locks and memory areas) are immediately released and available to other sessions.

A low value is desired for this measure. The detailed diagnosis capability, if enabled, lists all the sessions that were killed in this database.
Num_sniped_sessions Indicates the number of sessions that were idle for a period more than the profile's maximum idle time and were waiting for a response from the client. Number The idle time is the time limit that is provided against the IDLE_TIME parameter in the user's profile or the default profile. A low value is desired for this measure. The detailed diagnosis capability, if enabled, lists all the sniped sessions of this database.