| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Lock_requests
|
The average number of lock requests per second |
Locks/Sec
|
A high value indicates that there is high locking activity in the system and may need close scrutiny for the type of locks being requested. The detailed diagnosis for this measure provides a listing of locks requests for each lock type.
|
| Lock_waits
|
The average number of times there was lock contention as a percentage of the total number of lock requests |
Waits/Sec
|
A high value of waits can have an adverse impact on application performance. Possible reasons for this behavior could be:
- Inadequate number of locks available in the database
- Unusually high locking behavior of applications accessing the database
- Improper database application design, etc.
The detailed diagnosis for this measure provides a listing of waited number of locks for each lock type.
|
| Avg_lock_wait_time
|
The average amount of wait time for each lock request that resulted in a wait |
Secs
|
A high value may indicate that there is contention for locks in the system. When the average wait time for locks is high, users may have to wait for their transactions to complete.
|
| Lock_timeouts
|
The number of times a task was waiting for a lock and the transaction was rolled back due to a session-level or server-level lock timeout |
Timeouts/Sec
|
Lock timeouts can be useful for removing tasks that acquire some locks, and then wait for long periods of time blocking other users. The detailed diagnosis for this measure provides a listing of lock timeouts for each lock type.
|
| Dead_locks
|
The average number of deadlocks found in the lock requests |
Number
|
A deadlock may arise due to various situations including bad design of queries and deficient coding practices. A deadlock is a situation where both/all the lock requestors are in a mutual or a multi-way tie.
Any deadlocks are detrimental to database application performance.
The detailed diagnosis for this measure provides a listing of number of dead locks for each lock type.
|