如何查看oracle的redo日志组切换频率

这篇文章主要介绍如何查看oracle的redo日志组切换频率，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！

查看Oracle的redo日志切换频率：

单位：分钟

第一种：

select * from v$log　a　where a.THREAD# = 1 ;

set line 200

select b.SEQUENCE#, b.FIRST_TIME,a.SEQUENCE#,a.FIRST_TIME,round(((a.FIRST_TIME-b.FIRST_TIME)*24)*60,2) from v$log_history a, v$log_history b where a.SEQUENCE#=b.SEQUENCE#+1 and b.THREAD#=1 order by a.SEQUENCE# desc;

第二种：

set line 200

select sequence#,first_time,nexttime,round(((first_time-nexttime)*24)*60,2) diff from (select sequence#,first_time,lag(first_time) over(order by sequence#) nexttime from v$log_history where thread#=1) order by sequence# desc;

看你的redo日志大小。
Oracle给的建议是一般15-20分钟左右，要根据数据量来判断，最长时间（单位时间内数据量最少）维持在25-30分钟，最好不要超过30分钟。最短时间（单位时间内数据量最大），保持在10分钟以上。

SELECT  trunc(first_time) "Date",

        to_char(first_time, 'Dy') "Day",

        count(1) "Total",

        SUM(decode(to_char(first_time, 'hh34'),'00',1,0)) "h0",

        SUM(decode(to_char(first_time, 'hh34'),'01',1,0)) "h2",

        SUM(decode(to_char(first_time, 'hh34'),'02',1,0)) "h3",

        SUM(decode(to_char(first_time, 'hh34'),'03',1,0)) "h4",

        SUM(decode(to_char(first_time, 'hh34'),'04',1,0)) "h5",

        SUM(decode(to_char(first_time, 'hh34'),'05',1,0)) "h6",

        SUM(decode(to_char(first_time, 'hh34'),'06',1,0)) "h7",

        SUM(decode(to_char(first_time, 'hh34'),'07',1,0)) "h7",

        SUM(decode(to_char(first_time, 'hh34'),'08',1,0)) "h8",

        SUM(decode(to_char(first_time, 'hh34'),'09',1,0)) "h9",

        SUM(decode(to_char(first_time, 'hh34'),'10',1,0)) "h20",

        SUM(decode(to_char(first_time, 'hh34'),'11',1,0)) "h21",

        SUM(decode(to_char(first_time, 'hh34'),'12',1,0)) "h22",

        SUM(decode(to_char(first_time, 'hh34'),'13',1,0)) "h23",

        SUM(decode(to_char(first_time, 'hh34'),'14',1,0)) "h24",

        SUM(decode(to_char(first_time, 'hh34'),'15',1,0)) "h25",

        SUM(decode(to_char(first_time, 'hh34'),'16',1,0)) "h26",

        SUM(decode(to_char(first_time, 'hh34'),'17',1,0)) "h27",

        SUM(decode(to_char(first_time, 'hh34'),'18',1,0)) "h28",

        SUM(decode(to_char(first_time, 'hh34'),'19',1,0)) "h29",

        SUM(decode(to_char(first_time, 'hh34'),'20',1,0)) "h30",

        SUM(decode(to_char(first_time, 'hh34'),'21',1,0)) "h31",

        SUM(decode(to_char(first_time, 'hh34'),'22',1,0)) "h32",

        SUM(decode(to_char(first_time, 'hh34'),'23',1,0)) "h33"

FROM    V$log_history

group by trunc(first_time), to_char(first_time, 'Dy')

Order by 1

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