ORACLE识别低效执行的SQL 语句

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;