Understanding Peer-to-Peer Transactional Replication, Part 2

  • Comments posted to this topic are about the item Understanding Peer-to-Peer Transactional Replication, Part 2

  • Great Article when implementing peer to peer replication how did you find the latencies, and how wildly do they fluctuate for you? .. I know this is a "it depends answer" but just trying to get an understanding on how this behaves in the wild.

    would love to see something similar for merge replication too as I have an interest in both these replication technologies.

  • gregwhite83 (11/5/2015)


    Great Article when implementing peer to peer replication how did you find the latencies, and how wildly do they fluctuate for you? .. I know this is a "it depends answer" but just trying to get an understanding on how this behaves in the wild.

    Our PPTR implementation is done for redundancy/load balancing on a web application; the machines are physically close together on the same 10GB subnet; latencies are usually negligible.

    Part III talks about issues where mass updates introduce latency issues as distribution agents "catch up" with workloads. There are artefacts that must be closely monitored and addressed.

    Thanks

    John.

  • Thanks for the great detailed article in the continuing series.

  • Iwas Bornready (11/5/2015)


    Thanks for the great detailed article in the continuing series.

    You're welcome. Glad that you like it.

  • Thank you for providing this. I had to implement transactional replication without training and it wasn't pleasant. I still struggle with some aspects of it, especially the way the monitor works (not very intuitive). But I am confused about something on the difference between PPTR and Merge Replication. Both seem to be able to cross pollinate data with write capability. From what I read, even if there was a conflict (such as two nodes getting separate updates near simultaneously), there can be provisions made to resolve the conflict. So what is the practical difference?

  • jim.drewe (11/5/2015)


    Thank you for providing this. I had to implement transactional replication without training and it wasn't pleasant. I still struggle with some aspects of it, especially the way the monitor works (not very intuitive). But I am confused about something on the difference between PPTR and Merge Replication. Both seem to be able to cross pollinate data with write capability. From what I read, even if there was a conflict (such as two nodes getting separate updates near simultaneously), there can be provisions made to resolve the conflict. So what is the practical difference?

    Hi.

    First of all, Merge replication imposes an extra column with a GUID to control the merge. Merge is trigger-based. It uses a different sort of agent, the merge agent. Merge can be set to track column changes instead of just row changes.

    Peer-to-Peer is based on the transaction log, and is an amplification of classic transactional replication. Peer-to-peer uses a log reader agent and a distribution agent. It generates a SP and generates one call per row affected. That can add up to a lot of commands if a mass update is effected at one of the peers. Peer-to-peer is only in Enterprise Edition.

    I hope that I've answered your questions.

    Thanks

    John.

  • Excellent. Thanks.

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