45.oracle之Redo日志文件操作命令

1.查看目前的redo日志组

sql>select thread#,group#,members,bytes/1024/1024,status from v$log;

2.新增日志组

alter database add logfile thread 1 group 1 ('xxxx/xxx/redo01.log') size 200M;    # （thread 1） rac结构需要指定
alter database add logfile thread 1 group 2 ('xxxx/xxx/redo02.log') size 200M;
或者
alter database add logfile thread 1 group 3 ('xxxx/xxx/redo03a.log','xxxx/xxxx/redo03b') size 200M;
alter database add logfile thread 1 group 4('xxxx/xxx/redo04a.log','xxxx/xxxx/redo04b') size 200M;

3.drop日志组

##删除日志组时需要被删除的日志是inactive状态才可以
alter database drop logfile group 1;
alter database drop logfile group 2;

   然后在操作操作系统层面进行物理删除 rm

4.几个清除redo日志命令

alter database clear unarchived logfile group 2
alter database clear logfile group 2;

5.开启和关闭logfile线程　　

select THREAD#,STATUS,ENABLED FROM v$thread;
alter database enable|disable  thread 2;