Oracle RAC Session Waits Test
Like the wait activity on stand-alone Oracle servers, administrators also need to observe the wait activity on Oracle servers that are part of a Real Application Cluster (RAC). This test connects to the global view on the monitored Oracle server in an RAC, and pulls out critical statistics pertaining to the session-level cluster-related events that wait on the global cache or any other global resource on that Oracle server. Using this information, administrators can determine the cluster events on which the database spends most of its time, and which Oracle instances and current connections are responsible for the reported waits. This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick Oracle Database as the Component type, Performance as the Test type, choose this test from the disabled tests list, and click on the << button to move the test to the ENABLED TESTS list. Finally, click the Update button.
Note:
This test needs to be enabled only while monitoring the Oracle servers in an RAC environment.
Target of the test : An Oracle server
Agent deploying the test : An internal agent
Outputs of the test : One set of results for every cluster-related session wait event monitored on the Oracle server.
|
Measurement | Description | Measurement Unit | Interpretation |
---|---|---|---|
Total waits: |
Indicates the total number of times waits happened on this event since the last measurement period. |
Number |
If the value of this measure is very high, then you can drill down further using the detailed diagnosis capability (if enabled) of the eG Enterprise to discover which Oracle instances and current connections may be responsible for this. The detailed diagnosis of this measure reveals the Oracle instance on which the events are waiting, the session IDs of the sessions that caused the wait events to occur, the users who initiated the sessions, and the total number of waits, wait time, and the maximum wait time for every session. |
Total waits timedout: |
Indicates the total number of waits on this event that timed out since the last measurement period. |
Number |
A large number of timed out wait events is typically, undesirable. Use Oracle-specific documentation to probe the cause of the timeout. |
Avg time waited: |
Indicates the average duration for which the waits on this wait event persisted since the last measurement period. |
Secs |
Ideally, the value of this measure should be low. A very high value or a consistent increase in this value is indicative of a problem situation requiring further investigation. Use the detailed diagnosis capability to zoom into the session that has contributed to the abnormal increase in wait time. |
Max time waited: |
Indicates the high watermark of wait time for this wait event. |
Secs |
|