今天在自己机器做了个实验，插入10万条，由于空间少，重启数据库时出现：

SQL> startup
ORACLE instance started.

Total System Global Area 188743680 bytes
Fixed Size 1218460 bytes
Variable Size 167774308 bytes
Database Buffers 16777216 bytes
Redo Buffers 2973696 bytes
Database mounted.
ORA-16038: log 3 sequence# 103 cannot be archived
ORA-19502: write error on file "", blockno (blocksize=)
ORA-00312: online log 3 thread 1: '/home/lc_orauser/oradata/niutest/redo03.log'

?

后来发现是 闪回区的空间被全部占用

select group#,sequence#,archived,status from v$log;

GROUP# SEQUENCE# ARC STATUS
---------- ---------- --- ----------------
1 104 NO INACTIVE
3 103 NO INACTIVE
2 105 NO CURRENT

?

--清空闪回区空间，根据查询视图v$log可知，当前活动日志为2号日志组，则此时需要清空3号日志组的，

alter database clear unarchived logfile group 3;

然后再

alter database open;

解决了。