select group#,members from v$log;
查看日志文件的状态
select group#,status from v$log;
有状态来决定执行步骤
status:
active
alter system checkpoint;
alter database clear logfile group <group#>
inactive,unused
alter database clear logfile group <group#>
current
alter system switch logfile;
alter system checkpoint;
alter database clear logfile group <group#>