Oracle Rollbacks Test
The immediate availability of rollback segments for the various activities that occur in a database server is very critical. Contention for rollback segments can adversely impact the performance of a database server and hence, needs to be detected and reported immediately. To detect contention for rollback segments, the Oracle Rollbacks test monitors the degree of contention for buffers that contain rollback segment blocks.
Note:
This test will not report metrics for an Oracle 12c CDB server.
Target of the test : An Oracle server
Agent deploying the test : An internal agent
Outputs of the test : One set of results for every SID monitored.
|
Measurement | Description | Measurement Unit | Interpretation |
---|---|---|---|
System segment waits: |
Denotes the ratio of the number of waits for acquiring a header block or a block of the SYSTEM rollback segment to the total number of requests for data, measured over a period of time. |
Percent |
If the number of waits for any class of block exceeds 1% of the total number of requests, the size of the SYSTEM rollback segment needs to be increased. |
Non-system segment waits: |
Denotes the ratio of the number of waits for acquiring a header block or any other block of a non-SYSTEM rollback segment to the total number of requests for data, measured over a period of time. |
Percent |
If the number of waits for any class of block exceeds 1% of the total number of requests, the sizes of the existing rollback segments may need to be increased. Alternatively, additional rollback segments to may be created to reduce contention. |