实验:
session 1:SQL> show user;USER is "SYS"SQL>SQL> create table t_all_objs as select owner,object_id,object_name from all_objects where 0=1;Table created.SQL> alter table T_ALL_OBJS add constraint pk_t_all_objs primary key (OBJECT_ID);Table altered.SQL> insert into t_all_objs(owner,object_id,object_name) values('TEST',2013011701,'test1');1 row created.SQL> insert into t_all_objs(owner,object_id,object_name) values('TEST',2013011702,'test2');1 row created.SQL> commit;Commit complete.SQL> select sid from v$mystat where rownum<2; SID---------- 61SQL> SQL> select * from t_all_objs; OWNER OBJECT_ID OBJECT_NAME------------------------------ ---------- ------------------------------TEST 2013011701 test1TEST 2013011702 test2SQL> update t_all_objs set object_name='test11' where object_id=2013011701;1 row updated.未提交...................................session 2:SQL> update t_all_objs set object_name='test101' where object_id=2013011701; 1 row updated.hang住了...........................--显然是有阻塞,假设我们只知道阻塞的对象是T_ALL_OBJS表,则排障如下,主要是根据将object_id关联到v$session的ROW_WAIT_OBJ#,如下:set lines 200 pages 999col ORACLE_USERNAME for a14col OBJECT_NAME for a20col MACHINE for a14col OS_USER_NAME for a14col terminal for a14select l.session_id sid, s.serial#, l.locked_mode, l.oracle_username, l.os_user_name, s.machine, s.terminal, o.object_name, o.object_type, o.object_id, s.logon_time from v$locked_object l, dba_objects o, v$session s where l.object_id = o.object_id and o.object_name='T_ALL_OBJS' and l.session_id = s.sid order by sid, s.serial#; SID SERIAL# LOCKED_MODE ORACLE_USERNAM OS_USER_NAME MACHINE TERMINAL OBJECT_NAME OBJECT_TYPE OBJECT_ID LOGON_TIME---------- ---------- ----------- -------------- -------------- -------------- -------------- -------------------- ------------------- ---------- ------------ 59 165 3 SYS oracle wang pts/9 T_ALL_OBJS TABLE 89985 06-NOV-17 61 721 3 SYS oracle wang pts/8 T_ALL_OBJS TABLE 89985 06-NOV-17或者直接查询dba_object的object_id值。。。。。。。。。。。接着关联到ROW_WAIT_OBJ#=89985,即ROW_WAIT_OBJ#=object_idSQL> select sid,sql_id,status,blocking_session, ROW_WAIT_OBJ#,ROW_WAIT_FILE#,ROW_WAIT_BLOCK#,ROW_WAIT_ROW# from v$session where event='enq: TX - row lock contention' and ROW_WAIT_OBJ#=89985; SID SQL_ID STATUS BLOCKING_SESSION ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW#---------- ------------- -------- ---------------- ------------- -------------- --------------- ------------- 59 c53uad8st2u8t ACTIVE 61 89985 1 102393 0--接着根据blocking_seesin=61,查询:SQL> select sid,serial#,sql_id,status,event,blocking_session, ROW_WAIT_OBJ#,ROW_WAIT_FILE#,ROW_WAIT_BLOCK#,ROW_WAIT_ROW# from v$session where sid=61; SID SERIAL# SQL_ID STATUS EVENT BLOCKING_SESSION ROW_WAIT_OBJ# ROW_WAIT_FILE# ROW_WAIT_BLOCK# ROW_WAIT_ROW#---------- ---------- ------------- -------- ---------------------------------------------------------------- ---------------- ------------- -------------- --------------- ------------- 61 721 INACTIVE SQL*Net message from client -1 0 0 0--找到原因sid,杀掉:SQL> alter system kill session '61,721' immediate;System altered.SQL> --发现session 2已经提交了SQL> update t_all_objs set object_name='test101' where object_id=2013011701; 1 row updated.--commit提交后查询SQL> commit;Commit complete.SQL> select * from t_all_objs;OWNER OBJECT_ID OBJECT_NAME------------------------------ ---------- ------------------------------TEST 2013011701 test101TEST 2013011702 test2SQL> ============================================================================================或者直接用如下三种方法排查:
select SID,TYPE,ID1,ID2,LMODE,REQUEST,CTIME,BLOCK from V$lock whereblock=1 or request<>0;
SID TY ID1 ID2 LMODE REQUEST CTIME BLOCK
---------- -- ---------- ---------- ---------- ---------- ---------- ----------
59 TX 393249 10702 0 6 127 0
61 TX 393249 10702 6 0 135 1
select a.sid hold_sid, b.sid wait_sid, a.type, a.id1, a.id2, a.ctime
from v$lock a, v$lock b
where a.id1 = b.id1
and a.id2 = b.id2
and a.block = 1
and b.block = 0; HOLD_SID WAIT_SID TY ID1 ID2 CTIME---------- ---------- -- ---------- ---------- ---------- 61 59 TX 393249 10702 108select decode(request,0,'holder: ','waiter: ') ||
sid session_id, id1, id2, lmode, request, type
from v$lock
where (id1, id2, type) in (select id1, id2, type from v$lock where request > 0)
order by id1, request;SESSION_ID ID1 ID2 LMODE REQUEST TY------------------------------------------------ ---------- ---------- ---------- ---------- --holder: 61 393249 10702 6 0 TXwaiter: 59 393249 10702 0 6 TX
网站名称:tx锁之ROW_WAIT_OBJ#和object_id关联排障
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