查看哪些用户在使用数据库

select osuser, 
       a.username, 
       cpu_time / executions / 1000000 || 's', 
       sql_fulltext, 
       machine 
  from v$session a, v$sqlarea b 
 where a.sql_address = b.address 
 order by cpu_time / executions desc 
select osuser, 
       a.username, 
       cpu_time / executions / 1000000 || 's', 
       sql_fulltext, 
       machine 
  from v$session a, v$sqlarea b 
 where a.sql_address = b.address 
 order by cpu_time / executions desc