相克军_Oracle体系_随堂笔记014-锁 latch,lock

lock table  in [row share][row exclusive][share][share row exclusive][exclusive] mode;

grant select on v_$mystat to hr; 

select sid from v$mystat where rownum=1; 

update employees set last_name=last_name||‘a‘ where department_id=60; 

select xidusn,xidslot,xidsqn,status from v$transaction; 

select sid,type,id1,id2,
decode(lmode,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) lock_mode,   
decode(request,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) request_mode,
block
from v$lock
where sid=&sid; 

select object_name from dba_objects where object_id=&object_id; 

select trunc(393249/power(2,16)) as undo_blk#,bitand(393249,to_number(‘ffff‘,‘xxxx‘)) + 0 as slot# from dual;      

select sid from v$mystat where rownum=1; 

update employees set last_name=last_name||‘b‘ where department_id=60; 

select sid, type, id1, id2,
decode(lmode,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) lock_mode,
decode(request,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) request_mode,
block
from v$lock
where sid in(&sid1,&sid2)
order by sid;  

select sid from v$mystat where rownum=1; 

update employees set last_name=last_name||‘c‘ where department_id=60; 

select sid,type,
decode(request,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) request_mode
from v$enqueue_lock
where sid in(&sid1,&sid2); 

select a.sid blocker_sid, a.serial#, a.username as blocker_username, b.type,
decode(b.lmode,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) lock_mode,
b.ctime as time_held,c.sid as waiter_sid,
decode(c.request,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) request_mode,
c.ctime time_waited  
from   v$lock b, v$enqueue_lock c, v$session a  
where  a.sid = b.sid and    b.id1= c.id1(+) and b.id2 = c.id2(+) and c.type(+) = ‘TX‘ and  b.type = ‘TX‘ and  b.block   = 1
order by time_held, time_waited; 

alter system kill session ‘&sid,&serial‘; 

select sid from v$mystat where rownum=1; 

update employees set last_name=last_name||‘a‘ where department_id=60;
update departments set department_name=‘unknow‘ where department_id=10;
update locations set city=‘unknown‘ where location_id=1100;  

select sid, type, id1, id2,
decode(lmode,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) lock_mode,
decode(request,0,‘None‘,1,‘Null‘,2,‘Row share‘,3,‘Row Exclusive‘,4,‘Share‘,5,‘Share Row Exclusive‘,6,‘Exclusive‘) request_mode,block
from v$lock
where sid=&sid;  

select name, value from v$parameter where name in(‘transactions‘,‘dml_locks‘); 

select resource_name as "R_N", current_utilization as "C_U", max_utilization as "M_U", initial_allocation as "I_U"  
from v$resource_limit  
where resource_name in(‘transactions‘,‘dml_locks‘); 

select sid from v$mystat where rownum=1;
update employees set last_name=last_name||‘a‘ where employee_id=100 

select sid from v$mystat where rownum=1;
update employees set last_name=last_name||‘b‘ where employee_id=101; 

update employees set last_name=last_name||‘c‘ where employee_id=101; 

update employees set last_name=last_name||‘d‘ where employee_id=100;