可以根据TOP里面的SPID来查找原因，语句如下
SELECT a.osuser, a.username,b.address,b.hash_value, b.sql_text fromv$session a, v$sqltext b, v$process p
where p.spid = &spid
and p.addr = a.paddr
and a.STATUS = 'ACTIVE'
and a.sql_address =b.address
order by address, piece;

不过最好导出一份AWR报告结合ASH来看看