Home Database Mysql Tutorial 查看Oracle数据库表被锁例子故障定位

查看Oracle数据库表被锁例子故障定位

Jun 07, 2016 pm 05:05 PM

查看oracle数据库表被锁例子mdash;mdash;故障定位 1.开一个会话session1,(实际就是和数据库建立一个连接,可以通过第三方软件

查看Oracle数据库表被锁例子——故障定位

1.开一个会话session1,(实际就是和数据库建立一个连接,可以通过第三方软件,或者直接使用sqlplus来连接)

SQL>select sid from v$mystat where rownum=1;

SID

158

SQL>create table t(x int primary key);

table created

SQL>insert into t values(1);

commit;

SQL>update t1 set    t=10 where  x=1;

已更新一行;

2.再开一个会话

SQL>select sid from v$mystat where rowunm=1;

SID

157

SQL>update t1 se x=10 where x=1;

这个时候session2被session1锁住

锁的情况可以通过v$ock视图查看

SQL>select sid,type,id1,id2,LMODE,request,block from v$lock where sid in (157,158) order by sid;

sid      ty     id1                id2      lmode request block

157   TM    51349         0          3           0            0

157   TX    327699      292       0           6            0

158   TX    327699      292      6           0              1

158   TM    51349       0           3            0             1

这里sid=158 是第一个会话,sid=157是第二个会话,block=1表示这个会话正在阻塞其他的会话。

request=6表示当前会话正在等待一个LMODE=6的锁。意思是这个会话正在被阻塞。如果此列非0,就是在等待一个锁。

TX行级锁

TM表级锁

id1,id2定义了锁的相关信息,锁的模式有lmode决定

一般来说,系统如果平时运行正常,突然会停止不动,多半是被阻塞了(blcoked)

3.然后去确定用户的信息

sql>select  machine from v$session where sid in (158,157)

可以看到用户所使用的机器名

如果用户是通过中间件连接过来的,,那机器的名字是中间件服务器的名字,可能需要借助中间件服务器提供的连接信息来确定用户。

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