用下列sql工具找出低效sql:

 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;

     ( 虽然目前各种关于sql优化的图形化工具层出不穷,但是写出自己的sql工具来解决问题始终是一个最好的方法)