转自http://www.111cn.cn/database/109/b992816b1dddbb641c25c0999883427e.htm
declare @text nvarchar(max);
with tb
as
(
select blocking_session_id,
session_id,db_name(database_id) as dbname,text from master.sys.dm_exec_requests a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
),
tb1 as
(
select a.*,login_time,program_name,client_interface_name,login_name,cpu_time,memory_usage*8 as 'memory_usage(KB)',
total_scheduled_time,reads,writes,logical_reads
from tb a inner join master.sys.dm_exec_sessions b
on a.session_id=b.session_id
)
select @text=text from tb1 a inner join master.sys.dm_exec_connections b on a.session_id=b.session_id
print @text
/*
declare @text nvarchar(max);
with tb
as
(
select blocking_session_id,
session_id,db_name(database_id) as dbname,text from master.sys.dm_exec_requests a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
),
tb1 as
(
select a.*,login_time,program_name,client_interface_name,login_name,cpu_time,memory_usage*8 as 'memory_usage(KB)',
total_scheduled_time,reads,writes,logical_reads
from tb a inner join master.sys.dm_exec_sessions b
on a.session_id=b.session_id
)
select @text=text from tb1 a inner join master.sys.dm_exec_connections b on a.session_id=b.session_id
print @text
*/
还可以短一点：
declare @text nvarchar(max);
select @text=text
from master.sys.dm_exec_requests a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
print @text
/*
declare @text nvarchar(max);
select @text=text
from master.sys.dm_exec_requests a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
print @text
*/
1. SQL优化的原则是：
将一次操作需要读取的BLOCK数减到最低,即在最短的时间达到最大的数据吞吐量。
调整不良SQL通常可以从以下几点切入：
检查不良的SQL，考虑其写法是否还有可优化内容
检查子查询 考虑SQL子查询是否可以用简单连接� ......
