常用oracle查询总结

1.查找当前表级锁的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
where ao.object_id = lo.object_id and lo.session_id = sess.sid;

2.杀掉锁表进程：
alter system kill session ‘436,35123‘;

3.RAC环境中锁查找：
SELECT inst_id,DECODE(request,0,‘Holder: ‘,‘Waiter: ‘)||sid sess,
        id1, id2, lmode, request, type,block,ctime
FROM GV$LOCK
WHERE (id1, id2, type) IN
       (SELECT id1, id2, type FROM GV$LOCK WHERE request>0)
ORDER BY id1, request;
  

4.监控当前数据库谁在运行什么SQL语句
select osuser, username, sql_text 
from  v$session a, v$sqltext b
where  a.sql_address =b.address order by address, piece;

5.找使用CPU多的用户session
select a.sid,spid,status,substr(a.program,1,40) prog, a.terminal,osuser,value/60/100 value
from  v$session a,v$process b,v$sesstat c
where  c.statistic#=12 and 
       c.sid=a.sid and 
       a.paddr=b.addr 
       order by value desc;

6.查看死锁信息
SELECT (SELECT username
          FROM v$session
         WHERE SID = a.SID) blocker, a.SID, ‘is blocking‘,
       (SELECT username
          FROM v$session
         WHERE SID = b.SID) blockee, b.SID
  FROM v$lock a, v$lock b
 WHERE a.BLOCK = 1 AND b.request > 0 AND a.id1 = b.id1 AND a.id2 = b.id2;

7.具有最高等待的对象
SELECT   o.OWNER,o.object_name, o.object_type, a.event,
         SUM (a.wait_time + a.time_waited) total_wait_time
    FROM v$active_session_history a, dba_objects o
   WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE
     AND a.current_obj# = o.object_id
GROUP BY o.OWNER,o.object_name, o.object_type, a.event
ORDER BY total_wait_time DESC;

SELECT   a.session_id, s.osuser, s.machine, s.program, o.owner, o.object_name,
         o.object_type, a.event,
         SUM (a.wait_time + a.time_waited) total_wait_time
    FROM v$active_session_history a, dba_objects o, v$session s
   WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE
     AND a.current_obj# = o.object_id
     AND a.session_id = s.SID
GROUP BY o.owner,
         o.object_name,
         o.object_type,
         a.event,
         a.session_id,
         s.program,
         s.machine,
         s.osuser
ORDER BY total_wait_time DESC;

8.查询当前连接会话数
select s.value,s.sid,a.username
from
v$sesstat S,v$statname N,v$session A
where
n.statistic#=s.statistic# and
name=‘session pga memory‘
and s.sid=a.sid
order by s.value;

9.等待最多的用户
SELECT   s.SID, s.username, SUM (a.wait_time + a.time_waited) total_wait_time
    FROM v$active_session_history a, v$session s
   WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE
GROUP BY s.SID, s.username
ORDER BY total_wait_time DESC;

10.等待最多的SQL
SELECT   a.program, a.session_id, a.user_id, d.username, s.sql_text,
         SUM (a.wait_time + a.time_waited) total_wait_time
    FROM v$active_session_history a, v$sqlarea s, dba_users d
   WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE
     AND a.sql_id = s.sql_id
     AND a.user_id = d.user_id
GROUP BY a.program, a.session_id, a.user_id, s.sql_text, d.username;

11.查看消耗资源最多的SQL
SELECT hash_value, executions, buffer_gets, disk_reads, parse_calls
FROM V$SQLAREA
WHERE buffer_gets > 10000000 OR disk_reads > 1000000
ORDER BY buffer_gets + 100 * disk_reads DESC;

12.查看某条SQL语句的资源消耗
SELECT hash_value, buffer_gets, disk_reads, executions, parse_calls
FROM V$SQLAREA
WHERE hash_Value = 228801498 AND address = hextoraw(‘CBD8E4B0‘);

13.查询会话执行的实际SQL
SELECT   a.SID, a.username, s.sql_text
    FROM v$session a, v$sqltext s
   WHERE a.sql_address = s.address
     AND a.sql_hash_value = s.hash_value
     AND a.status = ‘ACTIVE‘
ORDER BY a.username, a.SID, s.piece;

14.显示正在等待锁的所有会话
SELECT * FROM DBA_WAITERS;

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