1.查看总消耗时间最多的前10条SQL语句

select *  from (select v.sql_id,  v.child_number,  v.sql_text,  v.elapsed_time,  v.cpu_time,  v.disk_reads,  rank() over(order by v.elapsed_time desc) elapsed_rank  from v$sql v) a  where elapsed_rank <= 10;

2.查看CPU消耗时间最多的前10条SQL语句

select *  from (select v.sql_id,  v.child_number,  v.sql_text,  v.elapsed_time,  v.cpu_time,  v.disk_reads,  rank() over(order by v.cpu_time desc) elapsed_rank  from v$sql v) a  where elapsed_rank <= 10;

3.查看消耗磁盘读取最多的前10条SQL语句

select *  from (select v.sql_id,  v.child_number,  v.sql_text,  v.elapsed_time,  v.cpu_time,  v.disk_reads,  rank() over(order by v.disk_reads desc) elapsed_rank  from v$sql v) a  where elapsed_rank <= 10;

4.查看当前数据库执行次数最多的SQL，例如，查询执行最频繁的TOP 15的SQL语句

SELECT SQL_TEXT, EXECUTIONS   FROM (SELECT SQL_TEXT, EXECUTIONS, RANK() OVER(ORDER BY EXECUTIONS DESC) EXEC_RANK  FROM V$SQLAREA)  WHERE EXEC_RANK <= 15;