ORACLE查询系统中阻塞情况~

在ORACLE中经常会碰到阻塞的情况发生，这个时候我们就需要快速的找出导致阻塞的原因，并尽快排除它，好让系统重新正常运行。

下面以死锁为例，来看看如何找出导致阻塞的会话并解决问题。

//SCOTT窗口1 SQL> select * from t2; ID ---------- 3 1 2 SQL> update t2 set id=12 where id=2; 1 row updated. SQL> //SCOTT窗口2 SQL> select * from t2; ID ---------- 3 1 2 SQL> update t2 set id=11 where id=3; 已更新 1 行。 SQL> update t2 set id=13 where id=2; //此时进入等待……卡住不动了 //SYS窗口 SQL> select c.terminal||' ('''||a.sid||','||c.serial#||''') is blocking '||b.sid ||','||d.serial# block_msg, a.block 2 from v$lock a,v$lock b,v$session c,v$session d 3 where a.id1=b.id1 4 and a.id2=b.id2 5 and a.block>0 6 and a.sid <>b.sid 7 and a.sid=c.sid 8 and b.sid=d.SID 9 ; BLOCK_MSG BLOCK ---------------------------------------- ---------- HWANG ('138,305') is blocking 153,15 1 SQL> select sid,serial#,username from v$session where username is not null; SID SERIAL# USERNAME ---------- ---------- ------------------------------ 136 179 SYS 138 305 SCOTT 153 15 SCOTT //这个时候可以杀掉那个BLOCKER SQL> alter system kill session'138,305'; System altered. //SCOTT窗口1 SQL> select * from t2; select * from t2 * ERROR at line 1: ORA-00028: your session has been killed SQL>