查询归档切换频率

set linesize 999
set pagesize 999    
column h0 format 999
    column h1 format 999
    column h2 format 999
    column h3 format 999
    column h4 format 999
    column h5 format 999
    column h6 format 999
    column h7 format 999
    column h8 format 999
    column h9 format 999
    column h10 format 999
    column h11 format 999
    column h12 format 999
    column h13 format 999
    column h14 format 999
    column h15 format 999
    column h16 format 999
    column h17 format 999
    column h18 format 999
    column h19 format 999
    column h20 format 999
    column h21 format 999
    column h22 format 999
    column h23 format 999
    column avg format 999.99
    column day format a6
    
    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 gv$log_history
       WHERE first_time >= trunc(SYSDATE) - 50
       and thread# = inst_id
    GROUP BY TRUNC (first_time), TO_CHAR (first_time, 'Dy')
    ORDER BY 1 DESC;