1.forcing log switches
sql> alter system switch logfile;
2.forcing checkpoints
sql> alter system checkpoint;
3.adding online redo log groups
sql> alter database add logfile [group 4] ('/disk3/log4a.rdo','/disk4/log4b.rdo') size 1m;
4.adding online redo log members
sql> alter database add logfile member '/disk3/log1b.rdo' to group 1, '/disk4/log2b.rdo' to group 2;
5.changes the name of the online redo logfile
sql> alter database rename file 'c:/oracle/oradata/oradb/redo01.log' to 'c:/oracle/oradata/redo01.log';
6.drop online redo log groups
sql> alter database drop logfile group 3;
7.drop online redo log members
sql> alter database drop logfile member 'c:/oracle/oradata/redo01.log';
8.clearing online redo log files
sql> alter database clear [unarchived] logfile 'c:/oracle/log2a.rdo';
9.using logminer analyzing redo logfiles #這個可能是8i的日志分析，10g的請看另一篇日志挖掘。
a. in the init.ora specify utl_file_dir = ' '
b. sql> execute dbms_logmnr_d.build('oradb.ora','c:"oracle"oradb"log');
c. sql> execute dbms_logmnr_add_logfile('c:"oracle"oradata"oradb"redo01.log', dbms_logmnr.new);
d. sql> execute dbms_logmnr.add_logfile('c:"oracle"oradata"oradb"redo02.log', dbms_logmnr.addfile);
e. sql> execute dbms_logmnr.start_logmnr(dictfilename=>'c:"oracle"oradb"log"oradb.ora');
f. sql> select * from v$logmnr_contents(v$logmnr_dictionary,v$logmnr_parameters v$logmnr_logs);
g. sql> execute dbms_logmnr.end_logmnr;
10.查看系統日志文件信息及大小
sql>select a.group#, a.sequence#,a.bytes/1024/1024 tsize , a.members,a.status,b.member,b.type from v$log a , v$logfile b where a.group#=b.group#;