Flashback Query

SELECT count(*) from table_name
AS OF TIMESTAMP TO_TIMESTAMP('2012-01-01 15:29:00','YYYY-MM-DD HH24:MI:SS');

如果回滚段的大小不足够保存到当前时间的，那么就要挖日志，使用logminer了。

logminer：

http://blog.youkuaiyun.com/lijun_blue/article/details/7088503

logminer恢复一例：

http://www.oracleblog.org/working-case/dba-always-bad-luck-with-careless-customer/