数据库锁介绍: https://www.jb51.net/article/248863.htm
1、查出锁定object的session的信息以及被锁定的object名
SELECT l.session_id sid, s.serial#, l.locked_mode, l.oracle_username, l.os_user_name, s.machine, s.terminal, o.object_name, s.logon_time FROM v$locked_object l, all_objects o, v$session s WHERE l.object_id = o.object_id AND l.session_id = s.sid ORDER BY sid, s.serial#;
2、查出锁定表的session的sid, serial#,os_user_name, machine name, terminal和执行的语句,比上面那段多出sql_text和action
SELECT l.session_id sid, s.serial#, l.locked_mode, l.oracle_username, s.user#, l.os_user_name, s.machine, s.terminal, a.sql_text, a.action FROM v$sqlarea a, v$session s, v$locked_object l WHERE l.session_id = s.sid AND s.prev_sql_addr = a.address ORDER BY sid, s.serial#;
3、查出锁定表的sid, serial#,os_user_name, machine_name, terminal,锁的type,mode
SELECT s.sid, s.serial#, s.username, s.schemaname, s.osuser, s.process, s.machine, s.terminal, s.logon_time, l.TYPE FROM v$session s, v$lock l WHERE s.sid = l.sid AND s.username IS NOT NULL ORDER BY sid;
4、这个语句将查找到数据库中所有的DML语句产生的锁,还可以发现,任何DML语句其实产生了两个锁,一个是表锁,一个是行锁。
SELECT /*+ rule */ s.username, DECODE(l.TYPE, "TM", "TABLE LOCK", "TX", "ROW LOCK", NULL) LOCK_LEVEL, o.owner, o.object_name, o.object_type, s.sid, s.serial#, s.terminal, s.machine, s.program, s.osuser FROM v$session s, v$lock l, dba_objects o WHERE l.sid = s.sid AND l.id1 = o.object_id(+) AND s.username IS NOT NULL;
5、如果发生了锁等待,我们可能更想知道是谁锁了表而引起谁的等待,以下的语句可以查询到谁锁了表,而谁在等待。
以下查询结果是一个树状结构,如果有子节点,则表示有等待发生。如果想知道锁用了哪个回滚段,还可以关联到V$rollname,其中xidusn就是回滚段的USN
SELECT LPAD(" ", DECODE(l.xidusn, 0, 3, 0)) || l.oracle_username user_name, o.owner, o.object_name, o.object_type, s.sid, s.serial# FROM v$locked_object l, dba_objects o, v$session s WHERE l.object_id = o.object_id AND l.session_id = s.sid ORDER BY o.object_id, xidusn DESC
alter system kill session 'sid,serial#';
alter system kill session'494,7355';
1、找到某表的锁 所属的sid,alter system kill session 'sid,serial#'
;即可
select v$lock.sid, decode(v$lock.type, "MR", "Media Recovery", "RT", "Redo Thread", "UN", "User Name", "TX", "Transaction", "TM", "DML", "UL", "PL/SQL User Lock", "DX", "Distributed Xaction", "CF", "Control File", "IS", "Instance State", "FS", "File Set", "IR", "Instance Recovery", "ST", "Disk Space Transaction", "TS", "Temp Segment", "IV", "Library Cache Invalida-tion", "LS", "Log Start or Switch", "RW", "Row Wait", "SQ", "Sequence Number", "TE", "Extend Table", "TT", "Temp Table", "Unknown") LockType, rtrim(owner) || "." || object_name object_name, decode(lmode, 0, "None", 1, "Null", 2, "Row-S", 3, "Row-X", 4, "Share", 5, "S/Row-X", 6, "Exclusive", "Unknown") LockMode, decode(request, 0, "None", 1, "Null", 2, "Row-S", 3, "Row-X", 4, "Share", 5, "S/Row-X", 6, "Exclusive", "Unknown") RequestMode, ctime, block b from v$lock, all_objects where sid > 6 and v$lock.id1 = all_objects.object_id;
2、查出被lock 的对象,然后 alter system kill session 'sid,serial#'
;
select object_id, session_id, serial#, oracle_username, os_user_name, s.process from v$locked_object a, v$session s where a.session_id = s.sid;
LOCK TABLE table_1 [,table_2, ..., table_n] IN lock_mode MODE NOWAIT
table_1,...,table_n: 一系列你想通过使用LOCK TABLE语句锁住的数据库表。
lock_mode: 对于某一数据库表你要设定的锁定模式。你可以从如下的锁定模式中任选一个。
NOWAIT: Oracle will not wait to lock the given Table(s), if the Table(s) is(are) not available
LOCK TABLE loan IN SHARE MODE ; LOCK TABLE region IN EXCLUSIVE MODE NOWAIT; LOCK TABLE acct IN SHARE UPDATE MODE; LOCK TABLE bank IN ROW EXCLUSIVE MODE NOWAIT; LOCK TABLE user IN SHARE ROW EXCLUSIVE MODE; LOCK TABLE branch IN ROW SHARE MODE NOWAIT; commit
到此这篇关于Oracle锁(lock)的文章就介绍到这了。希望对大家的学习有所帮助,也希望大家多多支持。
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