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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