The Lock Types chart shows lock statistics broken down by lock type.

There is one line on the chart for each lock type:

  • AllocUnit
  • Application
  • Database
  • Extent
  • File
  • HoBT
  • Index
  • Key
  • Metadata
  • Object
  • Page
  • RID (Rows)
  • Table

The following counters can be chosen by clicking the arrow next to the chart name:

Waits per Second

the rate at which lock requests cannot be satisfied immediately and require the caller to wait before being granted the lock.

Average Wait Time

the average wait time (in milliseconds) for each lock request that resulted in a wait.

Lock Requests per Second

the number of lock requests and lock conversion requests per second.

Timeouts per Second

the number of lock timeouts per second. By default, SQL Server never times out locks (they will wait forever). However many applications issue a SET LOCK_TIMEOUT statement to cause SQL Server to timeout their locks after the specified interval. This statistic shows how often these timeouts are being exceeded.

The SQL Server | Sessions drilldown | Details page can be used to view the Lock Timeout (@@LOCK_TIMEOUT) values for each connection.

Deadlocks per Second

the number of lock requests per second that resulted in a deadlock. A deadlock occurs when session A requests a lock that conflicts with a lock already held by session B, and then session B requests a lock that conflicts with one session A holds. SQL Server chooses one session as the deadlock victim, cancels that connection and rolls back any updates they had done.