Question

我正在尝试查询system_health扩展事件环形缓冲区中的死锁事件。到目前为止，我已经得到了如下的死锁图。我为缺乏参考而道歉;我丢失了发现此查询的页面：

SELECT 
    CAST(event_data.value('(event/data/value)[1]', 'nvarchar(max)') AS XML) AS DeadlockGraph
FROM 
(   SELECT XEvent.query('.') AS event_data 
    FROM 
    (   -- Cast the target_data to XML 
        SELECT CAST(target_data AS XML) AS TargetData 
        FROM sys.dm_xe_session_targets AS st 
        INNER JOIN sys.dm_xe_sessions AS s 
            ON s.address = st.event_session_address 
        WHERE name = N'system_health' 
          AND target_name = N'ring_buffer' 
    ) AS Data 
    -- Split out the Event Nodes 
    CROSS APPLY TargetData.nodes ('RingBufferTarget/event[@name="xml_deadlock_report"]') AS XEventData (XEvent)   
) AS tab (event_data);

我还想在这些事件的时间戳中加入一列。如果我运行内部查询，我会看到事件的时间戳位于事件本身的XML中：

<event name="xml_deadlock_report"
    package="sqlserver" id="123" version="1"
    timestamp="2013-07-23T16:25:25.495Z">

如何解析此时间戳并显示它？我使用TSQL解析XML的经验有限。

我试过这个：

SELECT
    CAST(event_data.value('/@timestamp', 'nvarchar(500)') AS datetime) AS [time],
    CAST(event_data.value('(event/data/value)[1]', 'nvarchar(max)') AS XML) AS DeadlockGraph

但我收到错误：

Msg 2390，Level 16，State 1，Line 2 XQuery [tab.event_data.value（）]：不支持顶级属性节点

此：

CAST(event_data.value('(event/@timestamp)', 'nvarchar(500)') AS datetime) AS [time],

产生此错误：

Msg 2389，Level 16，State 1，Line 2 XQuery [tab.event_data.value（）]： 'value（）'需要一个单例（或空序列），找到的操作数输入'xdt：untypedAtomic *'

Answer 1

更改此

CAST(event_data.value('(event/@timestamp)', 'nvarchar(500)') AS datetime) AS [time],

用这个

SELECT 
    event_data.value('(/event/@timestamp)[1]','VARCHAR(50)') AS TS1,
    event_data.value('(/event/@timestamp)[1]','DATETIMEOFFSET') AS TS2,
    ...

结果：

TS1                      TS2                               
------------------------ ----------------------------------
2013-07-23T17:49:46.072Z 2013-07-23 17:49:46.0720000 +00:00

检索扩展事件会话环缓冲区中死锁的时间戳

1 个答案: