SELECT * FROM v$archived_log ;
SELECT * FROM v$log ;
SELECT * FROM v$logfile ;
Query the switching frequency of redolong:
method 1:
select b.SEQUENCE#, b.FIRST_TIME,a.SEQUENCE#,a.FIRST_TIME,round(((a.FIRST_TIME-b.FIRST_TIME)*24)*60,2) from v$log_history a, v$log_history b where a.SEQUENCE#=b.SEQUENCE#+1 and b.THREAD#=1 order by a.SEQUENCE# desc;
Method 2:
select sequence#,first_time,nexttime,round(((first_time-nexttime)*24)*60,2) diff from (select sequence#,first_time,lag(first_time) over(order by sequence#) nexttime from v$log_history where thread#=1) order by sequence# desc;
If the switching frequency is too high (it is recommended to switch every 15~20 minutes), the size of the logfile should be enlarged:
1. Execute SELECT * FROM v$logfile ; view the existing logfile information
2. Create a new log group file that you need to create according to the maximum value of the existing group#
ALTER DATABASE ADD logfile GROUP 12 '/opt/oracle/oradata/orcl/redo12.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 13 '/opt/oracle/oradata/orcl/redo13.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 14 '/opt/oracle/oradata/orcl/redo14.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 15 '/opt/oracle/oradata/orcl/redo15.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 16 '/opt/oracle/oradata/orcl/redo16.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 17 '/opt/oracle/oradata/orcl/redo17.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 18 '/opt/oracle/oradata/orcl/redo18.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 19 '/opt/oracle/oradata/orcl/redo19.log' SIZE 5120m ;
ALTER DATABASE ADD logfile GROUP 20 '/opt/oracle/oradata/orcl/redo20.log' SIZE 5120m ;
Execute SELECT * FROM v$logfile ; confirm whether the new creation is successful:
3. Delete the current logfile
Execute SELECT * FROM v$log before delete; confirm log status; is INACTIVE.
ALTER database DROP logfile group 8;
ALTER database DROP logfile group 9;
ALTER database DROP logfile group 10;
ALTER database DROP logfile group 11;
Fourth, switch the current log
ALTER system switch logfile ;
alter system checkpoint;