工作中数据库经常出现内存,找了篇文章
参照CSDN，中国风(Roy)一篇死锁文章
阻塞：其中一个事务阻塞，其它事务等待对方释放它们的锁,同时会导致死锁问题。
整理人：中国风(Roy) 参照Roy_88的博客
http://blog.csdn.net/roy_88/archive/2008/07/21/2682044.aspx
日期:2008.07.20
************************************************************************************************************************/
--生成测试表Ta
if not object_id('Ta') is null
drop table Ta
go
create table Ta(ID int Primary key,Col1 int,Col2 nvarchar(10))
insert Ta
select 1,101,'A' union all
select 2,102,'B' union all
select 3,103,'C'
go
if not object_id('Ta') is null
drop table Ta
go
create table Ta(ID int Primary key,Col1 int,Col2 nvarchar(10))
insert Ta
select 1,101,'A' union all
select 2,102,'B' union all
select 3,103,'C'
go
生成数据:
/*
表Ta
ID Col1 Col2
----------- ----------- ----------
1 101 A
2 102 B
3 103 C (3 行受影响)
*/
表Ta
ID Col1 Col2
----------- ----------- ----------
1 101 A
2 102 B
3 103 C (3 行受影响)
*/
1、将处理阻塞减到最少:
2、不要在事务中请求用户输入
3、在读数据考虑便用行版本管理
4、在事务中尽量访问最少量的数据
5、尽可能地使用低的事务隔离级别
阻塞1(事务):
--测试单表
-----------------------连接窗口1(update\insert\delete)------------------------------
begin tran
--update
update ta set col2='BB' where ID=2
--或insert
--begin tran
-- insert Ta values(4,104,'D')
--或delete
--begin tran
-- delete ta where ID=1
--rollback tran
-------------------------连接窗口2（查询表）---------------------------------------------
begin tran
select * from ta
--rollback tran
--- --分析--------------------------------------------------
-->SQL SERVER 2005查询死锁进程
select
request_session_id as spid,
resource_type,
db_name(resource_database_id) as dbName,
resource_description,
resource_associated_entity_id,
request_mode as mode,
request_status as Status
from
sys.dm_tran_locks
--Result:
/*
进程ID 资源类型 数据库 资源描述 资源关链ID 锁类型 进程状态
----------- ------------- ------ -------------------- ----------------------------- ----- ------
59 DATABASE Gepro 0 S GRANT
58 DATABASE Gepro 0 S GRANT
57 DATABASE Gepro 0 S GRANT
56 DATABASE Gepro 0 S GRANT
58 PAGE Gepro 1:1904 72057594039435264 IS GRANT
57 PAGE Gepro 1:1904 72057594039435264 IX GRANT
58 OBJECT Gepro 853578079 IS GRANT
57 OBJECT Gepro 853578079 IX GRANT
57 KEY Gepro (020068e8b274) 72057594039435264 X GRANT
58 KEY Gepro (020068e8b274) 72057594039435264 S WAIT
(9 行受影响)
*/
-----------------------连接窗口1(update\insert\delete)------------------------------
begin tran
--update
update ta set col2='BB' where ID=2
--或insert
--begin tran
-- insert Ta values(4,104,'D')
--或delete
--begin tran
-- delete ta where ID=1
--rollback tran
-------------------------连接窗口2（查询表）---------------------------------------------
begin tran
select * from ta
--rollback tran
--- --分析--------------------------------------------------
-->SQL SERVER 2005查询死锁进程
select
request_session_id as spid,
resource_type,
db_name(resource_database_id) as dbName,
resource_description,
resource_associated_entity_id,
request_mode as mode,
request_status as Status
from
sys.dm_tran_locks
--Result:
/*
进程ID 资源类型 数据库 资源描述 资源关链ID 锁类型 进程状态
----------- ------------- ------ -------------------- ----------------------------- ----- ------
59 DATABASE Gepro 0 S GRANT
58 DATABASE Gepro 0 S GRANT
57 DATABASE Gepro 0 S GRANT
56 DATABASE Gepro 0 S GRANT
58 PAGE Gepro 1:1904 72057594039435264 IS GRANT
57 PAGE Gepro 1:1904 72057594039435264 IX GRANT
58 OBJECT Gepro 853578079 IS GRANT
57 OBJECT Gepro 853578079 IX GRANT
57 KEY Gepro (020068e8b274) 72057594039435264 X GRANT
58 KEY Gepro (020068e8b274) 72057594039435264 S WAIT
(9 行受影响)
*/
-->SQL SERVER 2000查询死锁进程
SELECT DISTINCT
'进程ID' = STR(a.spid, 4)
, '进程ID状态' = CONVERT(CHAR(10), a.status)
, '死锁进程ID' = STR(a.blocked, 2)
, '工作站名称' = CONVERT(CHAR(10), a.hostname)
, '执行命令的用户' = CONVERT(CHAR(10), SUSER_NAME(a.uid))
, '数据库名' = CONVERT(CHAR(10), DB_NAME(a.dbid))
, '应用程序名' = CONVERT(CHAR(10), a.program_name)
, '正在执行的命令' = CONVERT(CHAR(16), a.cmd)
, '登录名' = a.loginame
, '执行语句' = b.text
FROM master..sysprocesses a CROSS APPLY
sys.dm_exec_sql_text(a.sql_handle) b
WHERE a.blocked IN ( SELECT blocked
FROM master..sysprocesses )
-- and blocked <> 0
ORDER BY STR(spid, 4)
--Result
/*
进程ID 进程ID 状态 死锁进程ID 工作站名称 执行命令的用户 数据库名 应用程序名 正在执行的命令 登录名 执行语句
---- ---------- ------ ---------- ---------- ---------- ---------- ---------------- ---------------------------------------------------------------------- -------------------------
56 sleeping 0 DC91229126 sa Gepro Microsoft AWAITING COMMAND DC91229126FF442\Administrator SET STATISTICS XML OFF
57 sleeping 0 DC91229126 sa Gepro Microsoft AWAITING COMMAND DC91229126FF442\Administrator SET STATISTICS XML OFF
58 suspended 57 DC91229126 sa Gepro Microsoft SELECT DC91229126FF442\Administrator begin tran select * from ta
59 runnable 0 DC91229126 sa Gepro Microsoft SELECT DC91229126FF442\Administrator SELECT DISTINCT
60 sleeping 0 DC91229126 sa Gepro Toad for S AWAITING COMMAND DC91229126FF442\Administrator SET FMTONLY OFF;
62 sleeping 0 DC91229126 sa Gepro Toad for S AWAITING COMMAND DC91229126FF442\Administrator
*/
--查连接住信息(spid:57、58)
select connect_time,last_read,last_write,most_recent_sql_handle
from sys.dm_exec_connections where session_id in(57,58)
--查看会话信息
select login_time,host_name,program_name,login_name,last_request_start_time,last_request_end_time
from sys.dm_exec_sessions where session_id in(57,58)
--查看阻塞正在执行的请求
select
session_id,blocking_session_id,wait_type,wait_time,wait_resource
from
sys.dm_exec_requests
where
blocking_session_id>0--正在阻塞请求的会话的 ID。如果此列是 NULL，则不会阻塞请求
/*
session_id,blocking_session_id,wait_type,wait_time,wait_resource
58 57 LCK_M_S 2116437 KEY: 6:72057594039435264 (020068e8b274)
*/
--查看正在执行的SQL语句
select
a.session_id,sql.text,a.most_recent_sql_handle
from
sys.dm_exec_connections a
cross apply
sys.dm_exec_sql_text(a.most_recent_sql_handle) as SQL --也可用函数fn_get_sql通过most_recent_sql_handle得到执行语句
where
a.Session_id in(57,58)
/*
session_id text
----------- -----------------------------------------------
57 SET STATISTICS XML OFF
58 begin tran select * from ta
*/
'进程ID' = STR(a.spid, 4)
, '进程ID状态' = CONVERT(CHAR(10), a.status)
, '死锁进程ID' = STR(a.blocked, 2)
, '工作站名称' = CONVERT(CHAR(10), a.hostname)
, '执行命令的用户' = CONVERT(CHAR(10), SUSER_NAME(a.uid))
, '数据库名' = CONVERT(CHAR(10), DB_NAME(a.dbid))
, '应用程序名' = CONVERT(CHAR(10), a.program_name)
, '正在执行的命令' = CONVERT(CHAR(16), a.cmd)
, '登录名' = a.loginame
, '执行语句' = b.text
FROM master..sysprocesses a CROSS APPLY
sys.dm_exec_sql_text(a.sql_handle) b
WHERE a.blocked IN ( SELECT blocked
FROM master..sysprocesses )
-- and blocked <> 0
ORDER BY STR(spid, 4)
--Result
/*
进程ID 进程ID 状态 死锁进程ID 工作站名称 执行命令的用户 数据库名 应用程序名 正在执行的命令 登录名 执行语句
---- ---------- ------ ---------- ---------- ---------- ---------- ---------------- ---------------------------------------------------------------------- -------------------------
56 sleeping 0 DC91229126 sa Gepro Microsoft AWAITING COMMAND DC91229126FF442\Administrator SET STATISTICS XML OFF
57 sleeping 0 DC91229126 sa Gepro Microsoft AWAITING COMMAND DC91229126FF442\Administrator SET STATISTICS XML OFF
58 suspended 57 DC91229126 sa Gepro Microsoft SELECT DC91229126FF442\Administrator begin tran select * from ta
59 runnable 0 DC91229126 sa Gepro Microsoft SELECT DC91229126FF442\Administrator SELECT DISTINCT
60 sleeping 0 DC91229126 sa Gepro Toad for S AWAITING COMMAND DC91229126FF442\Administrator SET FMTONLY OFF;
62 sleeping 0 DC91229126 sa Gepro Toad for S AWAITING COMMAND DC91229126FF442\Administrator
*/
--查连接住信息(spid:57、58)
select connect_time,last_read,last_write,most_recent_sql_handle
from sys.dm_exec_connections where session_id in(57,58)
--查看会话信息
select login_time,host_name,program_name,login_name,last_request_start_time,last_request_end_time
from sys.dm_exec_sessions where session_id in(57,58)
--查看阻塞正在执行的请求
select
session_id,blocking_session_id,wait_type,wait_time,wait_resource
from
sys.dm_exec_requests
where
blocking_session_id>0--正在阻塞请求的会话的 ID。如果此列是 NULL，则不会阻塞请求
/*
session_id,blocking_session_id,wait_type,wait_time,wait_resource
58 57 LCK_M_S 2116437 KEY: 6:72057594039435264 (020068e8b274)
*/
--查看正在执行的SQL语句
select
a.session_id,sql.text,a.most_recent_sql_handle
from
sys.dm_exec_connections a
cross apply
sys.dm_exec_sql_text(a.most_recent_sql_handle) as SQL --也可用函数fn_get_sql通过most_recent_sql_handle得到执行语句
where
a.Session_id in(57,58)
/*
session_id text
----------- -----------------------------------------------
57 SET STATISTICS XML OFF
58 begin tran select * from ta
*/
处理方法:
法一：
--连接窗口2
begin tran
select * from ta with (nolock)--用nolock:业务数据不断变化中,如销售查看当月时可用。
begin tran
select * from ta with (nolock)--用nolock:业务数据不断变化中,如销售查看当月时可用。
法二：
阻塞2(索引):
处理方法: 加索引
法三：设置当前查询隔离级别
-----------------------------连接窗口2------------------------------------------------
SET TRANSACTION ISOLATION LEVEL READ COMMITTED --设置会话已提交读:指定语句不能读取已由其他事务修改但尚未提交的数据
begin tran
select * from ta
SET TRANSACTION ISOLATION LEVEL READ COMMITTED --设置会话已提交读:指定语句不能读取已由其他事务修改但尚未提交的数据
begin tran
select * from ta
1、事务要尽量短
原文地址:http://www.cnblogs.com/ilovexiao/archive/2010/05/21/1740645.html
本文转自温景良(Jason)博客园博客，原文链接：http://www.cnblogs.com/wenjl520/archive/2010/07/15/1777794.html，如需转载请自行联系原作者