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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