(1) Physical Standby uses the redo log directly applying mechnism which involves the Oracle datafile format, redo format and consistency
Logical Standby uses the LogMiner to do the SQL apply. Both apply could not be catch up with the primary if there are fairly workload ongoing.
Readable standby is a new feature in 11g, as mentioned above, some data might not be realtime
,大家互相学习
1. 不管是ARCH模式还是LGWR方式,日志传到备机总要有一定时间差的,不太可能完全同步
11G了解的不多,11g有个Physical standby with Real Time Query,不知道楼上是不是说的这个,不过这个好像是解决Physical standby模式下不能读的问题的
2. oracle不可能区分用户错误和正常操作之间的区别吧
dataguard主要是用来解决灾备问题,用户错误应该是用flashback或不完全恢复之类的技术手段来处理比较好吧