Oracle redo log 大小及组数的设置（在线修改日志组数目及组成员个数）(二)

6 rows selected.

SYS@ORCL>alter database drop logfile group 1;

Database altered.

SYS@ORCL>alter database drop logfile group 2;

Database altered.

SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ---------------- ---
3 50 ACTIVE YES
4 100 CURRENT NO
5 100 UNUSED YES
6 100 UNUSED YES

SYS@ORCL>alter system switch logfile;

System altered.

SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ---------------- ---
3 50 ACTIVE YES
4 100 ACTIVE YES
5 100 CURRENT NO
6 100 UNUSED YES
SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ---------------- ---
3 50 ACTIVE YES
4 100 ACTIVE YES
5 100 CURRENT NO
6 100 UNUSED YES

SYS@ORCL>alter system checkpoint; --强制执行检查点

System altered.

SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ---------------- ---
3 50 INACTIVE YES
4 100 ACTIVE YES
5 100 CURRENT NO
6 100 UNUSED YES

SYS@ORCL>alter database drop logfile group 3;

Database altered.

SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ---------------- ---
4 100 ACTIVE YES
5 100 CURRENT NO
6 100 UNUSED YES

4.向新创建的日志组添加成员
注意： 若在生产库中，则将新创建的成员放到不同的磁盘上
SYS@ORCL>alter system switch logfile;

System altered.

SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ---------------- ---
4 100 ACTIVE YES
5 100 ACTIVE YES
6 100 CURRENT NO

SYS@ORCL>alter system switch logfile;

System altered.

SYS@ORCL>select GROUP# ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

GROUP# SIZE_M STATUS ARC
---------- ---------- ----------------