查看Oracle的redo日志切换频率

1.Oracle log 每次切换会记录到告警日志中 设想写个方案来查看log切换频率来判断Oracle log是否应该更改大小。

2.sql

　　a.查看redo日志信息

select * from v$log

　　b.查看日志切换频率 

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;

　　或者

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;