oracle - 如何检查 Oracle 数据库是否存在长时间运行的查询

Question

我的应用程序使用 Oracle 数据库，速度缓慢或似乎完全停止。

如何找出哪些查询成本最高，以便我可以进一步调查？

Answer 1

这显示当前“ACTIVE”的 SQL:-

select S.USERNAME, s.sid, s.osuser, t.sql_id, sql_text
from v$sqltext_with_newlines t,V$SESSION s
where t.address =s.sql_address
and t.hash_value = s.sql_hash_value
and s.status = 'ACTIVE'
and s.username <> 'SYSTEM'
order by s.sid,t.piece
/

这显示了锁。有时事情进展缓慢，但这是因为它被阻塞等待锁:

select
  object_name, 
  object_type, 
  session_id, 
  type,         -- Type or system/user lock
  lmode,        -- lock mode in which session holds lock
  request, 
  block, 
  ctime         -- Time since current mode was granted
from
  v$locked_object, all_objects, v$lock
where
  v$locked_object.object_id = all_objects.object_id AND
  v$lock.id1 = all_objects.object_id AND
  v$lock.sid = v$locked_object.session_id
order by
  session_id, ctime desc, object_name
/

这对于查找长操作(例如全表扫描)来说是一个很好的选择。如果是因为大量空头操作，则不会显示任何内容。

COLUMN percent FORMAT 999.99 

SELECT sid, to_char(start_time,'hh24:mi:ss') stime, 
message,( sofar/totalwork)* 100 percent 
FROM v$session_longops
WHERE sofar/totalwork < 1
/