发现一个操作事务经常死锁,特别是客户端操作人数多的话,后面根据LOG发现执行时间长达数百毫秒。所以需要优化数据库分析
首先要勾选开启执行计划
然后输入对应的语句,然后执行,下面就有具体的查询计划,哪些占用了时间
语句类似这样insert into test(name) select 'aa' where not exists(seelct 1 from test where name = 'aa')
这个语句是会去扫描表test的,如果数据量大,比如test表包含了100万条记录,就非常有必要在test表对name 增加一个索引
非常有效果。
附加查看死锁脚本
create procedure [dbo].[sp_who_lock]
as
begin
declare @spid int,@bl int,
@intTransactionCountOnEntry int,
@intRowcount int,
@intCountProperties int,
@intCounter int
create table #tmp_lock_who (
id int identity(1,1),
spid smallint,
bl smallint)
IF @@ERROR<>0 RETURN @@ERROR
insert into #tmp_lock_who(spid,bl) select 0 ,blocked
from (select * from sysprocesses where blocked>0 ) a
where not exists(select * from (select * from sysprocesses where blocked>0 ) b
where a.blocked=spid)
union select spid,blocked from sysprocesses where blocked>0
IF @@ERROR<>0 RETURN @@ERROR
-- 找到临时表的记录数
select @intCountProperties = Count(*),@intCounter = 1
from #tmp_lock_who
IF @@ERROR<>0 RETURN @@ERROR
if @intCountProperties=0
select '现在没有阻塞和死锁信息' as message
-- 循环开始
while @intCounter <= @intCountProperties
begin
-- 取第一条记录
select @spid = spid,@bl = bl
from #tmp_lock_who where Id = @intCounter
begin
if @spid =0
select '引起数据库死锁的是: '+ CAST(@bl AS VARCHAR(10)) + '进程号,其执行的SQL语法如下'
else
select '进程号SPID:'+ CAST(@spid AS VARCHAR(10))+ '被' + '进程号SPID:'+ CAST(@bl AS VARCHAR(10)) +'阻塞,其当前进程执行的SQL语法如下'
DBCC INPUTBUFFER (@bl )
end
-- 循环指针下移
set @intCounter = @intCounter + 1
end
drop table #tmp_lock_who
return 0
end
附加查看语句执行时间:毫秒数
declare @ct datetime
set @ct = getdate()
select * from test
select datediff(ms,@ct,getdate()) as 'time'