logical standby 与phisical standby

liuyi8903 · 发表于 2006-4-29 07:35

lz看看data guard concepts吧！

上面都写得非常清楚！

redlover9999 · 发表于 2006-4-29 15:11

Physical standby databases
A physical standby database is physically identical to the primary database, with on-disk database structures that are identical to the primary database on a block-for-block basis. The physical standby database is updated by performing recovery (Redo Apply) on the redo information that is received from the primary database. It can either be recovering data or open for read-only reporting.
Logical standby databases
A logical standby database is logically identical to the primary database. The logical standby database is updated by using SQL Apply. This is done with the use of the LogMiner technology on the log information received from the primary database. The tables in a logical standby database can be used simultaneously for recovery and for other tasks such as reporting, summations, and queries.