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What Are The Differences Between Physical/logical Standby Databases? How Would You Decide Which One Is Best Suited For Your Environment? |
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Answer» Physical standby DB: As the name, it is physically (DATAFILES, schema, other physical IDENTITY) same copy of the primary database. It synchronized with the primary database with APPLY Redo to the standby DB. Logical Standby DB: As the name logical information is the same as the production database, it may be physical structure can be different. It synchronized with primary database though SQL Apply, Redo received from the primary database into SQL statements and then executing these SQL statements on the standby DB. We can open “physical stand by DB to “read only” and make it available to the APPLICATIONS users (Only select is allowed during this PERIOD). we can not apply redo logs received from primary database at this time. We do not see such issues with logical standby database. We can open the database in normal mode and make it available to the users. At the same time, we can apply archived logs received from primary database. For OLTP large transaction database it is better to choose logical standby database. Physical standby DB: As the name, it is physically (datafiles, schema, other physical identity) same copy of the primary database. It synchronized with the primary database with Apply Redo to the standby DB. Logical Standby DB: As the name logical information is the same as the production database, it may be physical structure can be different. It synchronized with primary database though SQL Apply, Redo received from the primary database into SQL statements and then executing these SQL statements on the standby DB. We can open “physical stand by DB to “read only” and make it available to the applications users (Only select is allowed during this period). we can not apply redo logs received from primary database at this time. We do not see such issues with logical standby database. We can open the database in normal mode and make it available to the users. At the same time, we can apply archived logs received from primary database. For OLTP large transaction database it is better to choose logical standby database. |
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