sql运行效率查询(oracle)

SELECT EXECUTIONS,
       DISK_READS,
       BUFFER_GETS,
       ROUND((BUFFER_GETS - DISK_READS) / BUFFER_GETS, 2) Hit_radio,
       ROUND(DISK_READS / EXECUTIONS, 2) Reads_per_run,
       SQL_TEXT
  FROM V$SQLAREA
WHERE EXECUTIONS > 0
   AND BUFFER_GETS > 0
   AND (BUFFER_GETS - DISK_READS) / BUFFER_GETS < 0.8
ORDER BY 4 DESC;