SQL Server Extended Events使用2：查询使用锁最多的对象
当我们怀疑可能存在高度争用的资源，并希望了解这些对象占用多少锁定。一旦识别锁定频率最高的对象，便可采取一些措施来优化对争用对象的访问。使用SQL Server Extended Events可以帮助我们获得对象使用的锁资源。
--先删除LockCounts Event Session
IF EXISTS(SELECT* FROM sys.server_event_sessionsWHEREname='LockCounts')
DROP EVENT sessionLockCounts ON SERVER
GO
DECLARE @dbid int
SELECT @dbid =db_id('AdventureWorks')
DECLARE @sql nvarchar(1024)
SET @sql = '
CREATE eventsession LockCounts ON SERVER
ADD EVENTsqlserver.lock_acquired (WHERE database_id ='+CAST(@dbidAS nvarchar)+')
ADD TARGETpackage0.synchronous_bucketizer (
SETfiltering_event_name=''sqlserver.lock_acquired'', source_type=0,source=''resource_0'')'
EXEC (@sql)
GO
ALTER EVENT sessionLockCounts ON SERVER
STATE=start
GO
--
-- Create asimple workload that takes locks.
--
USEAdventureWorks
GO
SELECT TOP 1 * FROM HumanResources.Department
GO
-- Bucketizingtarget output is available from the
--sys.dm_xe_session_targets dynamic management view in
-- XML format.
-- The followingquery joins the bucketizing target output with
-- sys.objectsto obtain the object names.
--
SELECT name, object_id, lock_count FROM
(SELECT objstats.value('.','bigint')AS lobject_id,
objstats.value('@count','bigint') AS lock_count
FROM (
SELECT CAST(xest.target_dataAS XML)
LockData
FROM sys.dm_xe_session_targets xest
JOIN sys.dm_xe_sessions xesONxes.address= xest.event_session_address
JOIN sys.server_event_sessions sesONxes.name = ses.name
WHERE xest.target_name= 'synchronous_bucketizer'ANDxes.name = 'LockCounts'
) Locks
CROSS APPLY LockData.nodes('//BucketizerTarget/Slot')AS T(objstats)
)LockedObjects
INNER JOIN sys.objects o
ONLockedObjects.lobject_id= o.object_id
WHERE o.type!= 'S' AND o.type= 'U'
ORDER BY lock_countdesc
GO
--
结果：
name object_id lock_count
-------------------------------
Department 805577908 2
(1 row(s) affected)
-- Stop theevent session.
--
ALTER EVENT SESSIONLockCounts ON SERVER
state=stop
GO
--Drop the eventsession
DROP EVENT SESSIONLockCounts ON SERVER