DB Roll Back, if replication Interupted

  • If Replication is interupted due to some reasons, what would be the status of Subsriber Database?

    Database would be Rolled Back or Not. if Not then how to Roll Back the Database

    Thanks

  • What type of replication ?


    * Noel

  • Replication deals with transactions. If there were an issue in the middle of the transaction, it would roll back. If it is committed, it's there.

  • Steve Jones - Editor (6/5/2008)


    Replication deals with transactions. If there were an issue in the middle of the transaction, it would roll back. If it is committed, it's there.

    If it is snapshot replication. Resumable snapshots are available only with "concurrent" option and IF the bcp threads = 1 but if either of those conditions is false you will have to start from scratch and the Subscriber DB will be in an inconsistent state.


    * Noel

  • I am using Merge Replication.

    when synchronization was in process , i disabled the netwrok connections

    then replication was stoped, but the subscription DB wasn't Rolled Back.

    How the Subscription DB is Rolled Back ?

  • zafar (6/5/2008)


    I am using Merge Replication.

    when synchronization was in process , i disabled the netwrok connections

    then replication was stoped, but the subscription DB wasn't Rolled Back.

    How the Subscription DB is Rolled Back ?

    You will have to make sure that Merge agent is running correctly. If it is in a bad state because of your "disabled Network" you will have to "re-enable the network" and let the agent run to completion.

    Synchronization does happens "transactionally" as Steve posted above.

    The entire syncronization set is re-applied if it was not delivered properly.


    * Noel

  • But wouldn't some transactions in merge be applied if they committed? It wouldn't necessarily roll back everything because the network dropped. My understanding is that merge is transactional two-way, but it has additional logic to handle updating the same records.

    Also, what is "rolled back"? To the beginning of the db? replication is always running, so the rollbacks occur to the beginning of some transaction set if there is an interruption. As transactions are committed (replication transactions) they are then permanent in that database.

  • Once again. Steve is correct. Transactionally commited data will remain in the database. If comunication link is broken, clients could potentially "see" the "partial" state. Merge replication is to be used knowing that convergence will EVENTUALLY happen.

    If the PO defines "Rollback" as the entire Operation in one single transaction then that is not what actually happens.


    * Noel

  • i am using Merge replication, and it doesn't rolling back the data that has been synchronized before the network connection was broken.

    How could i Roll Back that data ?

    Your quick response will be highly appreciated.

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