当前的group#是4,5,6SQL> select group#,status from v$log;    GROUP# STATUS---------- ----------------         4 INACTIVE         5 CURRENT         6 INACTIVE然后执行了下列语句：ALTER DATABASE ADD LOGFILE ('/arch/redo/redo7.log') size 1024M;ALTER DATABASE ADD LOGFILE ('/arch/redo/redo8.log') size 1024M;ALTER DATABASE ADD LOGFILE ('/arch/redo/redo9.log') size 1024M;ALTER DATABASE ADD LOGFILE ('/arch/redo/redo10.log') size 1024M;ALTER DATABASE ADD LOGFILE ('/arch/redo/redo11.log') size 1024M;ALTER DATABASE ADD LOGFILE ('/arch/redo/redo12.log') size 1024M;然后：SQL> select group#,status from v$log;    GROUP# STATUS---------- ----------------         1 UNUSED         2 UNUSED         3 UNUSED         4 INACTIVE         5 CURRENT         6 INACTIVE         7 UNUSED         8 UNUSED         9 UNUSEDredo 组 添加时， group#的使用原则就是 从1开始，有空着的group#就选择（就复用）这一点跟datafile 的管理是不同的：datafile的 号是不重用的。