The DML_LOCKS initialization parameter specifies the maximum number of DML locks. The purpose of DML locks is to guarantee the integrity of data being accessed concurrently by multiple users. DML locks prevent destructive interference of simultaneous conflicting DML and/or DDL operations.
This metric checks for the utilization of the lock resource against the values (percentage) specified by the threshold arguments. If the percentage of all active DML locks to the limit set in the DML_LOCKS initialization parameter exceeds the values specified in the threshold arguments, then a warning or critical alert is generated.
If DML_LOCKS is 0, this test fails to register. A value of 0 indicates that enqueues are disabled.
The rest of the information in this section is only valid for this metric when it appears in either the Enterprise Manager Grid Control or the Enterprise Manager Database Control (if applicable).
The following table shows how often the metric's value is collected and compared against the default thresholds. The 'Consecutive Number of Occurrences Preceding Notification' column indicates the consecutive number of times the comparison against thresholds should hold TRUE before an alert is generated.
|
Target Version |
Evaluation and Collection Frequency |
Upload Frequency |
Operator |
Default Warning Threshold |
Default Critical Threshold |
Consecutive Number of Occurrences Preceding Notification |
Alert Text |
|
pre-10g |
Every 15 Minutes |
After Every Sample |
> |
80 |
Not Defined |
3 |
%target% has reached %value%%% of the lock limit. |
SELECT resource_name name, 100*DECODE(initial_allocation, ' UNLIMITED', 0, current_utilization / initial_allocation) usage FROM v$resource_limit WHERE LTRIM(limit_value) != '0' AND LTRIM(initial_allocation) != '0' AND resource_name = 'dml_locks'
Increase the DML_LOCKS instance parameter by 10%.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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