Category: Replication

Jonathan Kehayias provides some tips on migrating (transactional) replicated databases when the cost of reinitializing is just too high:

The first part of building any plan is to know what specifically is being migrated or upgraded. This is important because the steps will be slightly different if you are only migrating or upgrading one part of the environment vs. the entire environment. It is also important to know where the distributor is for the configuration and whether or not the distribution database is going to be affected by the changes being made. In most cases it is a full environment migration to newer hardware or upgrade to newer release of SQL Server and the steps below will work. This is not the only way of migrating/upgrading large replicated databases but this is the one I have used for over 15 years at the date this post was written and it has been flawless.

Read on for more tips and a step-by-step process. With merge replication, of course, things are 40% more difficult.

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Steve Stedman wants to see how far behind transactional replication is:

Working with Transactional Replication with many of our SQL Server clients, one of the big questions that we are always asking is replication keeping up? Recently when deleting a few hundred million rows from a large table that is synced with transactional replication, I needed to programmatically check how the distribution was keeping up. The one measure that indicated that things were behind was the subscriber undistributed commands tab in the replication monitor. When the number of commands waiting to be applied was too large, I had to slow down my delete process.

Click through for an easy script. The really frustrating part is that transactional replication is easy but answering the same question with merge replication is a royal pain.

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Steve Stedman has a script for us:

When working with SQL Server transactional replication, one of the common checks to see if things look healthy is to insert a tracer token into the replication data stream and see how long it takes to get to the subscribers.

This is a process that can be very tedious if you have multiple publications to check, as you need to go to the replication monitor, click on the publisher, then go to tracer tokens tab and insert a tracer token. Then wait to see the result. If you need to do this more than a couple times, you may be waiting for a while.

As a result, Steve has created a way to simplify this. Click through for that script.

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Garland MacNeill takes us through a replication issue:

For the past couple of days, I’ve been working on getting transactional replication set up between a couple of servers in between other projects I’ve been working on. For the last day I kept running into the following error:

“The remote server <“server name”> does not exist, or has not been designated as a valid Publisher, or you may not have permissions to see available Publishers. ” 

Click through for the solution.

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Jonathan Kehayias has some good use cases for transactional replication:

Why in the world would you want to use Transactional Replication?  Isn’t that the thing that is impossible to manage, difficult to configure, and always prone to problems? As a consultant, I see a lot of scenarios where every problem becomes a nail because all you have is a hammer. Sometimes another technology can provide a solution to problems that exist but little is known about the technology, and Transactional Replication tends to fall into this scenario in my experience. In this post we are going to take a look some of the more common Transactional Replication use cases as well as some scenarios where it can be used to solve a business problem in a different way. As with anything, Transactional Replication is just another tool to have in your toolbox.

To be fair, merge replication is much more impossible to manage, difficult to configure, and prone to problems…

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Gonzalo Bissio covers one reason why initializing merge replication might be slow:

Since 1 week (Yes… 1 week) they were waiting for the replication re-initialization to finish since they introduced some changes on the system and they needed to reinitialize the replication again. The rate of the records between the publisher and the subscribers were too low (20 records per second). Since this application is used globally they write records on all of the regions (then the merge replication manage them).

Read on to see what Gonzalo’s company had going on and how they fixed it.

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