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SQL Snapshot Replication RRS feed

  • Question

  • Fellow SQLers,

    Can someone explain if sql snapshot replication does a complete refesh from publisher to subscriber every time snapshot cycle is run? Or, if after the initial snapshot,  is it just the changes of the data to those articles in the publisher that gets sent?

    thx

    MG

    Sunday, April 14, 2019 4:45 PM

Answers

  • Hi MG,

    Snapshot replication distributes data at a specific moment and does not monitor for updates to the data. When synchronization occurs, the entire snapshot is generated and sent to Subscribers. When the Subscriber receives an update, it overwrites its entire copy of the data with the information received from the Publisher. Snapshot replication is most appropriate when data changes are substantial but infrequent. Please refer to Snapshot Replication.

    Best regards,
    Cathy Ji

    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

    • Marked as answer by mg101 Monday, April 15, 2019 1:20 PM
    Monday, April 15, 2019 7:12 AM

All replies

  • Hi MG,

    Snapshot replication distributes data at a specific moment and does not monitor for updates to the data. When synchronization occurs, the entire snapshot is generated and sent to Subscribers. When the Subscriber receives an update, it overwrites its entire copy of the data with the information received from the Publisher. Snapshot replication is most appropriate when data changes are substantial but infrequent. Please refer to Snapshot Replication.

    Best regards,
    Cathy Ji

    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

    • Marked as answer by mg101 Monday, April 15, 2019 1:20 PM
    Monday, April 15, 2019 7:12 AM
  • Thanks Cathy
    Monday, April 15, 2019 1:20 PM
  • Just to clarify.

    Transactional Replication uses an initial "snapshot" to initialize the data the first time (using the same Snapshot method as Snapshot replication or a backup/restore), then tracks the transactions run against the published database and runs those transactions again on the subscribers. 

    https://docs.microsoft.com/en-us/sql/relational-databases/replication/types-of-replication?view=sql-server-2017


    Monday, April 15, 2019 1:41 PM
  • Hi tom,

    I am puzzled as to your comment " then tracks the transactions run against the published database and runs those transactions again on the subscribers.:"   I do not see anything like that in the link provided. It was my understanding that when a snapshot ran "again" it walked the articles "again" and pumps it all across.

    That is why the is locking until it is done.

    MG

    Monday, April 15, 2019 2:39 PM
  • In "Transactional Replication" it tracks the changes and plays them again.

    In Snapshot, it is complete delete and reload of the table.

    Monday, April 15, 2019 3:57 PM
  • snapshot replication does a complete refesh from publisher to subscriber every time snapshot cycle is run?

    Is how "Snapshot Replication" works

    after the initial snapshot,  is it just the changes of the data to those articles in the publisher that gets sent?

    Is how "Transactional Replication" works.
    Monday, April 15, 2019 7:12 PM