先查询会话占用内存情况，通常是由于程序中sql导致。

SELECT server 连接类型 ,s.status, s.username,  oSUSEr,
       NAME,  VALUE / 1024 / 1024 "占用内存MB", s.SID "会话ID",
       s.serial#, spid "操作系统进程ID",
       p.PGA_USED_MEM,  p.PGA_ALLOC_MEM, p.PGA_FREEABLE_MEM, p.PGA_MAX_MEM,
       'alter system kill session '''||s.sid||','||s.serial#||''' immediate;' kill_session
       
  FROM v$session s, v$sesstat st, v$statname sn, v$process p
 WHERE st.SID = s.SID
   AND st.statistic# = sn.statistic#
   AND sn.NAME LIKE 'session pga memory'
   AND p.addr = s.paddr
 ORDER BY VALUE DESC;