“Lock Summary” provides overview statistics about lock activity that took place during the sample interval.
“Total Lock Requests” reports the total number of lock requests.
“Avg Lock Contention” reports the average number of times there was lock contention as a percentage of the total number of lock requests.
If the lock contention average is high, study the lock detail information below.
See Chapter 3, “Locking Configuration and Tuning,” in Performance and Tuning: Locking for more information on tuning locking behavior.
“Deadlock Percentage” reports the percentage of deadlocks as a percentage of the total number lock requests.
If this value is high, see “Deadlocks by lock type”.
“Avg Hash Chain Length” reports the average number of locks per hash bucket during the sample interval. You can configure the size of the lock hash table with the configuration parameter lock hashtable size. If the average number of locks per hash chain is more than four, consider increasing the size of the hash table.
See “Configuring the lock hashtable (Lock Manager)” on page 47 in Performance and Tuning: Locking for more information.
Large inserts with bulk copy are an exception to this guideline. Lock hash chain lengths may be longer during large bulk copies.
