Deadlocks Detected

Description:  The total number of deadlocks that have occurred.

Usage:  This element can indicate that applications are experiencing contention problems. These problems could be caused by the following situations:

• Lock escalations are occurring for the database
• An application may be locking tables explicitly when system-generated row locks may be sufficient
• An application may be using an inappropriate isolation level when binding
• Catalog tables are locked for repeatable read
• Applications are getting the same locks in different orders, resulting in deadlock.

You may be able to resolve the problem by determining in which applications (or application processes) the deadlocks are occurring. You may then be able to modify the application to better enable it to execute concurrently. Some applications, however, may not be capable of running concurrently.

You can use the connection timestamp monitor elements (Last Reset Timestamp, Database Activation Timestamp, and Connection Request Start Timestamp) to determine the severity of the deadlocks. For example, 10 deadlocks in 5 minutes is much more severe than 10 deadlocks in 5 hours.

The descriptions for the related elements listed above may also provide additional tuning suggestions.