Replication questions

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1

We’re establishing a secondary site and are looking into how we can have the machines there active rather than warm standbys.

I’ve used Singlestore replication multiple times for replicating within the same datacenter; however is there any real-world experience on replicating over a VPN/WAN ?

  1. Is all replication asynchronous – ie: transaction commits are not delayed whilst the replica is updated ?
  2. Does replication spool the complete transaction or deltas; ie: will deleting and reinserting the same rows within a transaction be transmitted ?
  3. How can I monitor and resize the buffers for replication ?
  4. Can a database being replicated to redirect CUD operations to the primary ?
2

Thanks for your question, nlello. Glad to hear of your expansion! :dizzy: What version are you running?

3

From 7.6.9 to 7.6.13

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4

Hi Nello! Please let me know if you find this :point_down: helpful. Thanks

  1. Replication across clusters, which includes cross datacenter replication, only supports asynchronous mode. In asynchronous mode, writes on the primary cluster will never wait to be replicated to the secondary cluster. Furthermore, secondary cluster failures will never block the master.
  2. WITH FORCE DIFFERENTIAL replicates only the contents of the master database that are not already in the slave database.
  3. SHOW DATABASES EXTENDED command output summarizes the replication status and other information about the state of the databases present in the secondary MemSQL cluster. SHOW PARTITIONS EXTENDED on secondary-MA will display information such as replication role, the location of each partition, if it is locked, and other information. SHOW REPLICATION STATUS on a node shows the status of every replication process running on that node.
  4. If your primary cluster fails and you want to failover to a database on the secondary cluster, run the STOP REPLICATING db_name command on the secondary cluster master aggregator. This command promotes the database on the secondary cluster to the master database and the promoted database becomes available for reads and writes (DDL and DML). Re-point your application at the master aggregator in the cluster where the promoted database resides.After running STOP REPLICATING, you cannot resume replicating from the primary cluster. The link/replication is severed.
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