Oracle Active Data Guard Physical Standby as HVR Replicate Source Database

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  • #14687
    Anonymous
    Inactive

    What we have:

    1. Oracle Physical Standby (Being replicated by Oracle Active Data Guard from PROD) – Read Only DB
    2. There are two types of tables which are being replicated from PROD:
      1. Tables which have Supplemental Logging Enabled.
      2. Tables which do NOT have supplemental logging enabled.

    Goal:

    For tables which do NOT have supplemental logging enabled, we want to capture changes as they happen on the standby database.

     

    If we use HVR Replication with the Standby Database as Source Database, can it take care of the tables which do not have supplemental logging to the Target Database?

    #14688
    Mark
    Keymaster

    By default Oracle does not write the external row identifier (primary key or unique key, if there is on) to the transaction logs in case of updates (inserts and deletes are always fully logged). During replication a row identifier is required to know how to process the data downstream.

    Traditionally HVR requires supplemental logging to be enabled in order to fully capture the contents for an update, and we still document this as the best practice. However nowadays you can also set up HVR to capture the database’s ROWID as the surrogate key in an extra column, and use that to process the data downstream. Depending on your scenario this may work for you if there is no option to add supplemental logging to the tables on the source that don’t already have supplemental logging enabled.

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