1、查询oracle快照
 select t.snap_id as snap_id,
        to_char(t.startup_time, 'yyyy-mm-dd hh24:mi:ss') as "SQL第一次执行时间",
        to_char(t.begin_interval_time, 'yyyy-mm-dd hh24:mi:ss') as "快照开始时间",
        to_char(t.end_interval_time, 'yyyy-mm-dd hh24:mi:ss') as "快照结束时间"
   from DBA_HIST_SNAPSHOT t
  order by snap_id desc;
2、执行以下SQL，查询S执行时间最长的前10条SQL语句
 select *
   from (select round((t2.elapsed_time_delta / 1000000), 2) as "elapsed_time(s)",
                t2.executions_delta as "executions",
                round(((t2.elapsed_time_delta / 1000000) /
                      t2.executions_delta),
                      2) as "Elapsed Time per Exec (s)",
                round((t2.cpu_time_delta / t2.elapsed_time_delta) * 100, 2) as "%CPU",
                --round(t1.user_io_wait_time / t2.elapsed_time_delta * 100, 2) as "%IO",
                t1.sql_id as sql_id,
                t1.module as "sql module",
                t1.sql_text as sql_text,
                t1.sql_fulltext as sql_fulltext,
                to_char(t3.begin_interval_time, 'yyyy-mm-dd hh24:mi:ss') as "begin time",
                to_char(t3.end_interval_time, 'yyyy-mm-dd hh24:mi:ss') as "end time"
           from v$sqlarea t1, DBA_HIST_SQLSTAT t2, DBA_HIST_SNAPSHOT t3
          where t1.sql_id = t2.sql_id
            and t2.snap_id = t3.snap_id
            and t2.executions_delta is not null
            and t2.executions_delta <> 0
            and t2.elapsed_time_delta is not null
            and t2.elapsed_time_delta <> 0
               -- and t1.parsing_schema_name in ('FASP_PLATFORM')
            and t2.snap_id = &snap_id
          order by t2.elapsed_time_delta desc)
  where rownum <= 10;