Measures reported by MongoCursorTest
A cursor is a pointer to the result set of a query. Clients can iterate through a cursor to retrieve results. By default, cursors timeout after 10 minutes of inactivity. Cursors that remain open for long periods of time can drain valuable memory resources; so can those cursors that have been configured to not timeout at all. To avoid the unnecessary memory drain, the MongoCursorTest test instantly alerts administrators to an abnormally large number of open cursors and notimeout cursors.
Outputs of the test : One set of results for the MongoDB server monitored.
The measures made by this test are as follows:
| Measurement |
Description |
Measurement Unit |
Interpretation |
| Initiated_transactions |
Indicates the rate at which transactions are initiated. |
Transactions/Sec |
|
| Commited_transactions |
Indicates the rate at which transactions are committed. |
Transactions/Sec |
|
| Rolledback_transactions |
Indicates the rate at which transactions are rolledback. |
Transactions/Sec |
Ideally, the value of this measure should be very low. |
| Rollback_rate |
Indicates the percentage of initiated transactions that are rolled back. |
Percent |
A value close to 100% is a serious cause for concern, as it implies that almost all transactions have been rolledback. Rollbacks consume processing overheads excessively and reduce database performance. |
| Recent_checkpoint_time |
Indicates the amount of time taken to create the most recent checkpoint. |
Millisecs |
An increase in this value under steady write load may indicate saturation on the I/O subsystem. |
|