oracle查看锁阻塞-谁阻塞了谁

一模拟锁阻塞

#阻塞1

一个会话正在往一个大表写入大量数据的时候，另一个会话加字段：

#会话1

#会话2

会话2被阻塞了。

#阻塞2

模拟一个会话update一条记录，没提交。

另一个会话也update这一条记录：

会话2被阻塞了。

二简单查看阻塞链

select *from (select a.inst_id,a.sid, a.serial#,a.sql_id,a.event,a.status,connect_by_isleaf as isleaf,sys_connect_by_path(SID, '<-') tree,level as tree_levelfrom gv$session astart with a.blocking_session is not nullconnect by nocycle a.sid = prior a.blocking_session)where isleaf = 1order by tree_level asc;

输出示例：

TREE这里可以看到阻塞链（从右往左看），这里是：

978阻塞了729；

372阻塞了616。

三查看具体谁阻塞了谁

SELECT DISTINCT s1.inst_id as blocking_inst_id,s1.username as blocking_username,s1.machine as blocking_machine,s1.sid as blocking_sid,s1.serial# as blocking_serial#,c1.sql_text as blocking_sql_text,s1.status as blocking_staus,s1.event as blocking_event,
s2.inst_id as waiting_inst_id,s2.username as waiting_username,s2.machine waiting_machine,s2.sid as waiting_sid,s2.serial# as waiting_serial#,c2.sql_text as waiting_sql_text,s2.status as blocking_staus,s2.event as waiting_eventFROM gv$lock l1,gv$session s1,gv$lock l2,gv$session s2,gv$sqlarea c1,gv$sqlarea c2,gv$process b1,gv$process b2WHERE     s1.sid = l1.sidAND s2.sid = l2.sidAND s1.inst_id = l1.inst_idAND s2.inst_id = l2.inst_idAND s1.paddr = b1.addrAND s2.paddr = b2.addrAND c1.SQL_ID=s1.PREV_SQL_ID       AND s2.sql_hash_value = c2.hash_valueAND l1.block > 0AND l2.request > 0AND l1.id1 = l2.id1AND l1.id2 = l2.id2
UNION
SELECT DISTINCT s1.inst_id as blocking_inst_id,s1.username as blocking_username,s1.machine as blocking_machine,s1.sid as blocking_sid,s1.serial# as blocking_serial#,c1.sql_text as blocking_sql_text,s1.status as blocking_staus,s1.event as blocking_event,
s2.inst_id as waiting_inst_id,s2.username as waiting_username,s2.machine waiting_machine,s2.sid as waiting_sid,s2.serial# as waiting_serial#,c2.sql_text as waiting_sql_text,s2.status as blocking_staus,s2.event as waiting_eventFROM gv$lock l1,gv$session s1,gv$lock l2,gv$session s2,gv$sqlarea c1,gv$sqlarea c2,gv$process b1,gv$process b2WHERE     s1.sid = l1.sidAND s2.sid = l2.sidAND s1.inst_id = l1.inst_idAND s2.inst_id = l2.inst_idAND s1.paddr = b1.addrAND s2.paddr = b2.addrAND c1.hash_value=s1.sql_hash_valueAND c1.address=s1.sql_addressAND s2.sql_hash_value = c2.hash_valueAND l1.block > 0AND l2.request > 0AND l1.id1 = l2.id1AND l1.id2 = l2.id2

#备注

union前的sql可以查看源端执行过的sql（在一个事务里执行了，但是还没提交）。

union后的sql可以查看当前源端正在执行的sql。

一次性展示不全，这里分三个截图展示：