该脚本可以用于列出Oracle日志文件切换的频率图:

REM Log Switch Frequency Map

col Day for a10
col Date for a10
set linesize 80


SELECT trunc(first_time) "Date",
       to_char(first_time, 'Dy') "Day",
       count(1) "Total",
       SUM(decode(to_char(first_time, 'hh24'), '00', 1, 0)) "h0",
       SUM(decode(to_char(first_time, 'hh24'), '01', 1, 0)) "h1",
       SUM(decode(to_char(first_time, 'hh24'), '02', 1, 0)) "h2",
       SUM(decode(to_char(first_time, 'hh24'), '03', 1, 0)) "h3",
       SUM(decode(to_char(first_time, 'hh24'), '04', 1, 0)) "h4",
       SUM(decode(to_char(first_time, 'hh24'), '05', 1, 0)) "h5",
       SUM(decode(to_char(first_time, 'hh24'), '06', 1, 0)) "h6",
       SUM(decode(to_char(first_time, 'hh24'), '07', 1, 0)) "h7",
       SUM(decode(to_char(first_time, 'hh24'), '08', 1, 0)) "h8",
       SUM(decode(to_char(first_time, 'hh24'), '09', 1, 0)) "h9",
       SUM(decode(to_char(first_time, 'hh24'), '10', 1, 0)) "h10",
       SUM(decode(to_char(first_time, 'hh24'), '11', 1, 0)) "h11",
       SUM(decode(to_char(first_time, 'hh24'), '12', 1, 0)) "h12",
       SUM(decode(to_char(first_time, 'hh24'), '13', 1, 0)) "h13",
       SUM(decode(to_char(first_time, 'hh24'), '14', 1, 0)) "h14",
       SUM(decode(to_char(first_time, 'hh24'), '15', 1, 0)) "h15",
       SUM(decode(to_char(first_time, 'hh24'), '16', 1, 0)) "h16",
       SUM(decode(to_char(first_time, 'hh24'), '17', 1, 0)) "h17",
       SUM(decode(to_char(first_time, 'hh24'), '18', 1, 0)) "h18",
       SUM(decode(to_char(first_time, 'hh24'), '19', 1, 0)) "h19",
       SUM(decode(to_char(first_time, 'hh24'), '20', 1, 0)) "h20",
       SUM(decode(to_char(first_time, 'hh24'), '21', 1, 0)) "h21",
       SUM(decode(to_char(first_time, 'hh24'), '22', 1, 0)) "h22",
       SUM(decode(to_char(first_time, 'hh24'), '23', 1, 0)) "h23",
       round(count(1) / 24, 2) "Avg"
  FROM V$log_history
 group by trunc(first_time), to_char(first_time, 'Dy')
 Order by 1
/