Oracle数据库突然宕机
查看日志发现（E:\app\Administrator\diag\rdbms\orcl\orcl\trace\alert_orcl.log）
日志中报错
Thread 1 cannot allocate new log, sequence 287072
Checkpoint not complete
参照：http://blog.csdn.net/huaishu/article/details/16886111
select group#,sequence#,bytes,members,status from v$log;
alter database add logfile group 4 ('E:\APP\ADMINISTRATOR\ORADATA\ORCL\redo04.log') size 200M;
alter database add logfile group 5 ('E:\APP\ADMINISTRATOR\ORADATA\ORCL\redo05.log') size 200M;
alter database add logfile group 6 ('E:\APP\ADMINISTRATOR\ORADATA\ORCL\redo06.log') size 200M;
alter system switch logfile;
alter database drop logfile group 1;