Lock:Timeout Event Class

The Lock:Timeout event class indicates that a request for a lock on a resource, such as a page, has timed out because another transaction is holding a blocking lock on the required resource. Time-out is determined by the @@LOCK_TIMEOUT system function and can be set with the SET LOCK_TIMEOUT statement.

Use the Lock:Timeout event class to monitor when time-out conditions occur. This information is useful to determine if time-outs are significantly affecting the performance of your application, and which objects are involved. You can examine the application code that modifies these objects to determine if changes to minimize time-outs can be made.

Lock:Timeout events with a duration of 0 are commonly the result of internal lock probes and are not necessarily an indication of a problem. The Lock:Timeout (timeout > 0) event can be used to ignore time-outs with a duration of 0.

Lock:Timeout Event Class Data Columns

Data column name Data type Description Column ID Filterable
ApplicationName nvarchar Name of the client application that created the connection to an instance of SQL Server. This column is populated with the values passed by the application rather than the displayed name of the program. 10 Yes
BinaryData image Lock resource identifier. 2 Yes
ClientProcessID int ID assigned by the host computer to the process where the client application is running. This data column is populated if the client provides the client process ID. 9 Yes
DatabaseID int ID of the database in which the lock time-out occurred. SQL Server Profiler displays the name of the database if the ServerName data column is captured in the trace and the server is available. Determine the value for a database by using the DB_ID function. 3 Yes
DatabaseName nvarchar Name of the database in which the time-out occurred. 35 Yes
Duration bigint Amount of time (in microseconds) between the time the lock request was issued and the lock was timed out. 13 Yes
EndTime datetime Time at which the event ended. 15 Yes
EventClass int Type of event = 27. 27 No
EventSequence int The sequence of a given event within the request. 51 No
GroupID int ID of the workload group where the SQL Trace event fires. 66 Yes
HostName nvarchar Name of the computer on which the client is running. This data column is populated if the client provides the host name. To determine the host name, use the HOST_NAME function. 8 Yes
IntegerData2 int Identified for informational purposes only. Not supported. Future compatibility is not guaranteed. 55 Yes
IsSystem int Indicates whether the event occurred on a system process or a user process. 1 = system, 0 = user. 60 Yes
LoginName nvarchar Name of the login of the user (either SQL Server security login or the Microsoft Windows login credentials in the form of DOMAIN\username). 11 Yes
LoginSid image Security identification number (SID) of the logged-in user. You can find this information in the sys.server_principals catalog view. Each SID is unique for each login in the server. 41 Yes
Mode int The resulting mode after the time-out.

0=NULL - Compatible with all other lock modes (LCK_M_NL)

1=Schema Stability lock (LCK_M_SCH_S)

2=Schema Modification Lock (LCK_M_SCH_M)

3=Shared Lock (LCK_M_S)

4=Update Lock (LCK_M_U)

5=Exclusive Lock (LCK_M_X)

6=Intent Shared Lock (LCK_M_IS)

7=Intent Update Lock (LCK_M_IU)

8=Intent Exclusive Lock (LCK_M_IX)

9=Shared with intent to Update (LCK_M_SIU)

10=Shared with Intent Exclusive (LCK_M_SIX)

11=Update with Intent Exclusive (LCK_M_UIX)

12=Bulk Update Lock (LCK_M_BU)

13=Key range Shared/Shared (LCK_M_RS_S)

14=Key range Shared/Update (LCK_M_RS_U)

15=Key Range Insert NULL (LCK_M_RI_NL)

16=Key Range Insert Shared (LCK_M_RI_S)

17=Key Range Insert Update (LCK_M_RI_U)

18=Key Range Insert Exclusive (LCK_M_RI_X)

19=Key Range Exclusive Shared (LCK_M_RX_S)

20=Key Range Exclusive Update (LCK_M_RX_U)

21=Key Range Exclusive Exclusive (LCK_M_RX_X)
32 Yes
NTDomainName nvarchar Windows domain to which the user belongs. 7 Yes
NTUserName nvarchar Windows user name. 6 Yes
ObjectID int ID of the object which was timed out, if available and applicable. 22 Yes
ObjectID2 bigint ID of the related object or entity, if available and applicable. 56 Yes




58 Yes
RequestID int ID of the request containing the statement. 49 Yes
ServerName nvarchar Name of the instance of SQL Server being traced. 26 No
SessionLoginName nvarchar Login name of the user who originated the session. For example, if you connect to SQL Server using Login1 and execute a statement as Login2, SessionLoginName shows Login1; while LoginName shows Login2. This column displays both SQL Server and Windows logins. 64 Yes
SPID int ID of the session on which the event occurred. 12 Yes
StartTime datetime Time at which the event started, if available. 14 Yes
TextData ntext Text value dependent on the lock type that was being acquired when the time-out occurred. 1 Yes
TransactionID bigint System-assigned ID of the transaction. 4 Yes












57 Yes

See Also

sp_trace_setevent (Transact-SQL)
Lock:Timeout (timeout > 0) Event Class
sys.dm_tran_locks (Transact-SQL)