解析oracle对select加锁的技巧以及锁的查询
发布时间:2021-12-08 14:54:12 所属栏目:教程 来源:互联网
导读:解析oracle对select加锁的方法以及锁的查询 一、oracle对select加锁方法 复制代码 代码如下: create table test(a number,b number); insert into test values(1,2); insert into test values(3,4); insert into test values(8,9); commit; ---session 1 模
解析oracle对select加锁的方法以及锁的查询 一、oracle对select加锁方法 复制代码 代码如下: create table test(a number,b number); insert into test values(1,2); insert into test values(3,4); insert into test values(8,9); commit; ---session 1 模拟选中一个号码 SQL> select * from test where a =1 for update skip locked; A B ---------- ---------- 1 2 ---session 2 对a=1再进行select SQL> select * from test where a = 1 for update skip locked; 未选定行 -- session 3 全表select SQL> select * from test for update skip locked; A B ---------- ---------- 3 4 8 9 SQL> 二、查询那些用户,操纵了那些表造成了锁机 复制代码 代码如下: SELECT 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,all_objects o WHERE l.sid = s.sid AND l.id1 = o.object_id(+) AND s.username is NOT Null 三、查出被锁的表,和锁住这个表的会话ID select a.session_id ,b.* from v$locked_object a,all_objects b where a.object_id=b.object_id 四、 查出对应的SQL语句 复制代码 代码如下: select vs.SQL_TEXT,vsess.sid,vsess.SERIAL#,vsess.MACHINE,vsess.OSUSER ,vsess.TERMINAL,vsess.PROGRAM,vs.CPU_TIME,vs.DISK_READS from v$sql vs,v$session vsess where vs.ADDRESS=vsess.SQL_ADDRESS and vsess.sid=(上面查出来的会话ID) 五、 1.查哪个过程被锁 查V$DB_OBJECT_CACHE视图: SELECT * FROM V$DB_OBJECT_CACHE WHERE OWNER='过程的所属用户' AND LOCKS!='0'; 2. 查是哪一个SID,通过SID可知道是哪个SESSION. 查V$ACCESS视图: SELECT * FROM V$ACCESS WHERE OWNER='过程的所属用户' AND; 3. 查出SID和SERIAL# 查V$SESSION视图: SELECT SID,SERIAL#,PADDR FROM V$SESSION WHERE SID='刚才查到的SID' 查V$PROCESS视图: SELECT SPID FROM V$PROCESS WHERE ADDR='刚才查到的PADDR'; 4. 杀进程 (1).先杀ORACLE进程: ALTER SYSTEM KILL SESSION '查出的SID,查出的SERIAL#'; (2).再杀操作系统进程: KILL -9 刚才查出的SPID 或 ORAKILL 刚才查出的SID 刚才查出的SPID 六、查找最耗费系统资源的SQL 复制代码 代码如下: --CPU select b.sql_text, a.buffer_gets, a.executions, a.buffer_gets/decode(a.executions , 0 , 1 , a.executions), c.username from V$sqlarea a, v$sqltext_with_newlines b, dba_users c where a.parsing_user_id = c.user_id and a.address = b.address order by a.buffer_gets desc , b.piece 复制代码 代码如下: --IO select b.sql_text, a.disk_reads, a.executions, a.disk_reads/decode(a.executions , 0 , 1 , a.executions), c.username from v$sqlarea a, v$sqltext_with_newlines b, dba_users c where a.parsing_user_id = c.user_id and a.address = b.address order by a.disk_reads desc , b.piece 复制代码 代码如下: select s.sid,s.value "CPU Used" from v$sesstat s,v$statname n where s.statistic#=n.statistic# and n.name='CPU used by this session' and s.value>0 order by 2 desc; (编辑:我爱故事小小网_铜陵站长网) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |