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我正在尝试编写脚本以将 sql server 中的扩展事件数据导入表中。

我目前正在使用以下查询，

 select getdate() as [check_date], 
 xml.value('(./@name)[1]','nvarchar(60)') as [event_name], 
 dateadd(hour, 9, xml.value('(./@timestamp)[1]', 'datetime')) AS [timestamp], 
 xml.value('(data[@name="wait_type"]/text)[1]','nvarchar(max)') as [wait_type], 
 xml.value('(data[@name="opcode"]/text)[1]','nvarchar(max)') as [opcode], 
 xml.value('(data[@name="duration"]/value)[1]','bigint') as [duration], 
 xml.value('(data[@name="signal_duration"]/value)[1]','bigint') as [signal_duration], 
 xml.value('(data[@name="wait_resource"]/value)[1]','nvarchar(max)') as [wait_resource], 
 xml.value('(action[@name="client_app_name"]/value)[1]', 'nvarchar(max)') as [client_app_name],
 xml.value('(action[@name="client_hostname"]/value)[1]', 'nvarchar(max)') as [client_hostname], 
 xml.value('(action[@name="database_id"]/value)[1]', 'int') as [database_id], 
 xml.value('(action[@name="server_principal_name"]/value)[1]', 'nvarchar(max)') as [server_principal_name], 
 xml.value('(action[@name="sql_text"]/value)[1]', 'nvarchar(max)') as [sql_text], 
 xml.value('(action[@name="attach_activity_id_xfer"]/value)[1]', 'char(36)') as [attach_activity_id_xfer], 
 xml.value('(action[@name="attach_activity_id"]/value)[1]', 'char(36)') as [attach_activity_id_guid] , 
 substring(reverse(xml.value('(action[@name="attach_activity_id"]/value)[1]', 'nvarchar(max)')), 0,charindex('-', reverse(xml.value('(action[@name="attach_activity_id"]/value)[1]', 'nvarchar(100)')))) as [attach_activity_id_seq]   
 from [my_temporaly_xml_table_here] with (nolock)  
 CROSS APPLY target_xml.nodes('/RingBufferTarget/event[  @name=sql:variable("@p_event_name") and @timestamp > sql:variable("@p_lasttimestamp") ]') AS x(xml)

这些是我的索引，我决定使用选择性索引来提高性能，看起来使用选择性索引执行得很好，但结果并不好。此查询当前正在发生不可接受的逻辑读取。

好吧，当然数百个事件基本上是在生产服务器中触发的。

CREATE SELECTIVE XML INDEX sxidx_001
ON [my_temporaly_xml_table_here] (xml)  
FOR  
(  
--eventnode =  '/RingBufferTarget/event' as xquery 'node()', 
eventdatanode =  '/RingBufferTarget/event/data' as xquery 'node()', 
eventactionnode =  '/RingBufferTarget/event/action' as xquery 'node()', 
dataname =  '/RingBufferTarget/event/data/@name' as xquery 'xs:string' singleton,
actionname =  '/RingBufferTarget/event/action/@name' as xquery 'xs:string' singleton,
timestamp=  '/RingBufferTarget/event/@timestamp' as xquery 'xs:dateTime' singleton


)

有什么更好的性能建议吗？

4

0 回答 0