如何查詢鎖等待

1）查看當前的用戶會話和對應的鎖信息 

select s.sid,s.SERIAL#,s.USERNAME,s.STATUS,l.ID1,l.LMODE,l.REQUEST
 from v$session s,v$lock l
 where s.SID=l.SID and s.USERNAME is not null;

說明：

a.  username字段爲空-------後臺進程會話

b.  request字段-----------會話申請的鎖類型

• 0 - none
• 1 - null (NULL)
• 2 - row-S (SS)
• 3 - row-X (SX)
• 4 - share (S)
• 5 - S/Row-X (SSX)
• 6 - exclusive (X)

c.  lmode字段-----------會話持有鎖類型

• 0 - none
• 1 - null (NULL)
• 2 - row-S (SS)
• 3 - row-X (SX)
• 4 - share (S)
• 5 - S/Row-X (SSX)
• 6 - exclusive (X)

2）查看造成鎖等待的鎖的信息

 

select l.ID1,l.LMODE,l.REQUEST
 from v$session s,v$lock l
 where s.LOCKWAIT=l.KADDR;

3）查找造成鎖等待的會話信息

select s.SID,s.SERIAL#
 from v$session s,v$lock l
 where l.ID1 in (select distinct l2.ID1 from v$session s2,v$lock l2 where s2.LOCKWAIT=l2.KADDR)
       and s.SID=l.SID and l.LMODE<>0;

4）kill掉不釋放鎖的會話

alter system kill session 'sid,serial#';   --sid,serial# 爲3）中查詢