Does Replication Use Compression?

Does SQL Server replication impliment any kind of compression? It seems to me that this would be very helpful for congested WAN links and costly merge replication.

Hi Joshua,

Here is a direct quote from book online

http://msdn2.microsoft.com/en-us/library/ms151740.aspx

Does replication work over low bandwidth connections? Does it use compression?

Yes, replication does work over low bandwidth connections. For connections over TCP/IP, it uses the compression provided by the protocol but does not provide additional compression. For Web synchronization connections over HTTPS, it uses the compression provided by the protocol and also additional compression of the XML files used to replicate changes. For more information about replicating over low bandwidth connections, see A Slow Network Is Causing Problems.

So I guess the answer is no to your question. However, merge replication only sends the net changes rather all the changes at your publisher side. More more info, refer to the following quote from book online.

http://msdn2.microsoft.com/en-us/library/ms152565.aspx

Merge Replication

Merge replication is typically used in server-to-client environments. Merge replication is appropriate in any of the following situations:

Multiple Subscribers might update the same data at various times and propagate those changes to the Publisher and to other Subscribers.

Subscribers need to receive data, make changes offline, and later synchronize changes with the Publisher and other Subscribers.

Each Subscriber requires a different partition of data.

Conflicts might occur and, when they do, you need the ability to detect and resolve them.

The application requires net data change rather than access to intermediate data states. For example, if a row changes five times at a Subscriber before it synchronizes with a Publisher, the row changes only once at the Publisher to reflect the net data change (that is, the fifth value).
|||There are also hardware compression solutions out there that will compress the data before it goes across the network.|||

Compression seems like it should be a given, I hope MS decides to add this. For our situation, we have large amounts of data changes and while the connections are reliable, they may not always be ultra fast.

The doc quoted states that it can make use of the compression provided by the protocol, does that mean you could you use gzip?

|||Agreed, data compression across the wire is something that's being considered for future releases of SQL Server replication.