ExtendEvent-判断DB是否有在使用

会话可以捕获所有执行的SQL语句，但是这样捕获的数据量太大，所以要进行一些筛选。比如账号，DB，影响行数。

查询的结果建议插入实体表，万一SSMS会话出现问题，零时表数据消失，还得重新查询，时间太久了。

EventTime是SQL执行完成时的时间点，

duration单位是微秒 1s=1000000us

select
    LEFT(SWITCHOFFSET(n.value('@timestamp','Datetime'),'+08:00'),23) as EventTime,
        n.value('(data[@name="row_count"]/value)[1]', 'bigint') as row_count,
    n.value('(data[@name="duration"]/value)[1]', 'bigint') as duration,
    n.value('(data[@name="statement"]/value)[1]', 'nvarchar(max)') as statement,
    n.value('(action[@name="database_name"]/value)[1]', 'nvarchar(128)') as database_name,
    n.value('(action[@name="client_app_name"]/value)[1]', 'nvarchar(128)') as client_app_name,
    n.value('(action[@name="username"]/value)[1]', 'nvarchar(128)') as username,
    n.value('(action[@name="client_hostname"]/value)[1]', 'nvarchar(128)') as client_hostname
    into #tmp
from
(select cast(event_data as XML) as event_data
from sys.fn_xe_file_target_read_file('M:\XEvent\DB_Usage_0*.xel', null, null, null)) ed
cross apply ed.event_data.nodes('event') as q(n)
order by EventTime  desc 

select   *  from  #tmp

生成的xel文件，建议最大就是1G，1G的解析时间大概20分钟，而10G要解析8个多小时，文件的修改时间为最后写入的时间（不是创建的时间），以此来判断需要解析哪些文件。

CREATE EVENT SESSION [DB_Usage] ON SERVER
ADD EVENT sqlserver.sql_statement_completed(SET collect_statement=(1)
    ACTION(sqlserver.client_app_name,sqlserver.client_hostname,sqlserver.
database_name,sqlserver.nt_username,sqlserver.sql_text,sqlserver.username))
ADD TARGET package0.event_file(SET filename=N'D:\XEvent\DB_Usage.xel')
WITH (MAX_MEMORY=4096 KB,EVENT_RETENTION_MODE=ALLOW_SINGLE_EVENT_LOSS,
MAX_DISPATCH_LATENCY=30 SECONDS,MAX_EVENT_SIZE=0 KB,MEMORY_PARTITION_MODE=NONE,TRACK_CAUSALITY=OFF,STARTUP_STATE=ON)
GO