ORACLE lock table solutions and methods of finding SQL statements that cause lock tables

1. View the lock table status in the current system in ORACLE 
select * from v$locked_object 
You can get the sid and objectid by querying v$locked_object, and then use the sid and v$session linked list to query where the locked table is, and use v$session in The objectid field is associated with the id field of dba_objects to query detailed lock table conditions.

查询SQL如下： 
select sess.sid, 
       sess.serial#, 
       lo.oracle_username, 
       lo.os_user_name, 
       ao.object_name, 
       lo.locked_mode 
  from v$locked_object lo, dba_objects ao, v$session sess, v$process p 
where ao.object_id = lo.object_id 
   and lo.session_id = sess.sid;

查询是什么SQL引起了锁表的原因，SQL如下： 
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#;

2. ORACLE unlock method 
alter system kill session '156'; –156 is the locked process number, namely spid