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Restarting Merge Replication after a few months break RRS feed

  • Question

  • I have Merge Replication running on a central Distributor with two push subscriptions. Due to IT issues, the two 2 subscriber merge agent jobs have been disabled for some months. During this period one of the subscriber databases has been constantly updated but the other has been static. Obviously the replicated database on the distributor is also a few months out of date too.

    Can I simply re-enable the subscriber merge agent jobs? I would have thought that Merge Replication should be able resume this way, albeit with a rather large merge to start with. I don't want to trigger a new snapshot as the database on the Distributor is months out of date.

    If a new snapshot is required I imagine that I would have to backup up the current Subscriber (i.e. currently active) database and restore it to the Distributor before creating a new snapshot. That in turn probably require removing the subscriptions (after scripting them of course) and recreating them.

    Restarting the existing agent jobs sound much simpler, if it will work.


    R Campbell

    Wednesday, December 5, 2018 10:25 PM

Answers

  • As soon as you start your subscriptions will be marked as expired. You will need to try to re-initialize with subscriber upload. This may upload the subscriber side data to the publisher and then send down a new snapshot. If you are lucky this will work.

    As a safety measure I would backup the subscriber databases copy them over to your publisher and restore them there under different names. Then use a tool like RedGate data compare to do data comparisions to figure out what is in the subscriber databases and what to migrate to the publisher.

    • Proposed as answer by Bob_FT Thursday, December 6, 2018 3:37 PM
    • Marked as answer by Dick Campbell Thursday, December 6, 2018 8:02 PM
    Thursday, December 6, 2018 2:44 PM
    Moderator

All replies

  • I am afraid that I could not understand you clearly. Any update ?
    Thursday, December 6, 2018 8:58 AM
  • Hi R Campbell,

     

    >>During this period one of the subscriber databases has been constantly updated but the other has been static. Obviously the replicated database on the distributor is also a few months out of date too.

     

    Could you please tell us whether the replicated database on the distributor was not changed after disabling the jobs.

    And just one subscriber database is changed and the other database was also not changed.

     

    Best Regards,
    Emily


    MSDN Community Support
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    Thursday, December 6, 2018 9:11 AM
  • Hi R Campbell,

     

    >>During this period one of the subscriber databases has been constantly updated but the other has been static. Obviously the replicated database on the distributor is also a few months out of date too.

     

    Could you please tell us whether the replicated database on the distributor was not changed after disabling the jobs.

    And just one subscriber database is changed and the other database was also not changed.

     

    Best Regards,
    Emily


    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com


    Naming the databases on the two subscribers database A and database B and the database on the distributor database D. Normally database A is the only “active” database. Inserts and updates of database are normally pulled up to database D then pushed down to database B. When I disabled the merge agent jobs on the distributor a few mounths ago, database A remained active and bases D and B became dormant. Some background information. The computer that hosts database A is a “Primary” SCADA sever logging factory production data and managing control recipes. Database D is accessed by corporate users for reports, based on replicated data from database A. Database B is hosted on the “Standby” SCADA server which, as its name suggests, only comes into play if the Primary SCADA fails. Replication ensures that database B is up-to-date when this happens.

    R Campbell

    Thursday, December 6, 2018 10:45 AM
  • As soon as you start your subscriptions will be marked as expired. You will need to try to re-initialize with subscriber upload. This may upload the subscriber side data to the publisher and then send down a new snapshot. If you are lucky this will work.

    As a safety measure I would backup the subscriber databases copy them over to your publisher and restore them there under different names. Then use a tool like RedGate data compare to do data comparisions to figure out what is in the subscriber databases and what to migrate to the publisher.

    • Proposed as answer by Bob_FT Thursday, December 6, 2018 3:37 PM
    • Marked as answer by Dick Campbell Thursday, December 6, 2018 8:02 PM
    Thursday, December 6, 2018 2:44 PM
    Moderator
  • Thanks, I would normally take the safe approach and start all over again with a back up the subscription database of choice, database A in this case. Before doing so I wanted to ask whether not or re-enabling the existing merge agent jobs. It sounds like the “easy way” is too risky.

    R Campbell


    Thursday, December 6, 2018 8:06 PM