Deadlocks Detected

Snapshot Information Level
Database
Application

API Structure(s)
sqlm_dbase
sqlm_appl

Monitor Group
Basic
Lock

Resettable

Yes

Event Information Level
Database
Connection

API Structure(s)
sqlm_db_event
sqlm_conn_event

API Element Name
Element Type

deadlocks
counter

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 timestamps monitor elements ("First Database Connect 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.

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