Transactional Replication SQL Server – Purposes & Implementation

In an SQL Server environment, there are numerous procedures that assist users with specific operations. One similar operation is the transactional replication SQL Server. In this article, we will discuss and learn more about this procedure, understanding its functioning and implementation. 

So, without any further delays, let’s first learn briefly about what transactional replication is.

What is Transactional Replication in SQL?

If we simplify the term, it is basically a way to copy the data from a SQL Server database to another in a synchronized manner. This method is very beneficial in situations where the users wish to create one or more copies of their data to stay closely in sync, like in situations of data sharing across multiple locations. Let’s now take a look at the basic components used for the transactional replication SQL Server process.

• Publisher – This is the main or source database from which the data is to be copied.
• Distributor – The distributor is responsible for storing the changes and passing them from the source to the target database/server.
• Subscriber – the target database that receives the data from the publisher.

Any change made in the source server or database is stored in the transaction log and is further sent to the distributor. The next process is responsible for updating these changes to the subscriber database. With the complete process happening simultaneously, the target database is always synchronized with the publisher.

This is the entire process explanation of the transactional replication. Let’s now proceed with the use case scenarios where this process is beneficial and where it is required. 

Use Cases of Transactional Replication in SQL Server

There are different situations where transactional replication is required and is beneficial in various aspects. Here are some of these use case scenarios:

• When users need a real-time reporting of data.
• In cases where the data is supposed to be shared across multiple locations.
• For database synchronization among applications.
• To migrate data to a new server or database.

These are the possible use case scenarios that use transactional replication. Let’s now learn how transactional replication is implemented. 

Also Read: What is Peer To Peer Replication In SQL Server and how it can be configured?

Execution of Transactional Replication SQL Server

To understand the process in a better way, we must know the key concepts of the process. Here are the important concepts that we need to understand before the process initiation:

• Snapshot Initialization
  The process includes taking a snapshot of the published articles for the first synchronization.
• Log Reader Agent
  The log reader agent works on the Distributor and is responsible for monitoring the transaction log at the Publisher. 
• Distribution Agent
  The Distribution agent is responsible for delivering the transactions from the distributor to the Subscriber and can run simultaneously for real-time transactional replication. 
• Data Consistency
  This is one of the crucial aspects to understand. The data consistency here means that all the changes made to the subscriber are in the exact same order as they were made at the publisher. 

This is a theoretical explanation of how the method is implemented and how it works. We will now take a look at the thorough steps of how the process is executed for a better understanding of the users.

Transactional Replication SQL Server – Steps Explained

There are a few prerequisites to follow before jumping right to the process. This will help you execute the process more safely and also keep the data secure throughout. Let’s learn these prerequisites for better implementation of the process. 

• Ensure that the SQL Server Agent is enabled on all the servers involved in the process.
• Check the network connection between the three components: Publisher, Distributor, and Subscriber. 
• Check and ensure there are no compatibility issues between the Publisher and Subscriber.
• Grant all the required permissions for the process to be executed. 

These steps will help with the execution, preventing any major issues from occurring. Now, it’s time to learn the technicalities of the process. 

Set Up the Publisher in SSMS

1. In SQL Server Management Studio, expand replication. Then right-click on local publications and select new publication.
2. Next, choose the database you wish to publish and then select transactional publication.
3. Now, choose the articles(tables, stored procedures, etc.). Then, select the snapshot schedule and configure the security for the snapshot agent.
4. Finish the process and create the publication. 

After setting up the publisher, it’s time to set up the distributor in the database. Let’s see how that can be done. 

Configuring the Distributor With SSMS

1. The first step is to connect to the publisher instance in SSMS.
2. Then, right-click on the replication and choose Configure Distribution.
3. Next, either choose a remote distributor or select the ‘Use the Server As Its Own Distributor’ option.
4. Select a snapshot folder and complete the process. 

After this process, the distributor will be configured. Now it’s time to set up the Subscriber in the database. 

Setting up the Subscriber in the Database

1. Firstly, expand the created publisher in SSMS. 
2. Then, right-click on the publisher and find new subscriptions. 
3. Next, choose Pull or Push subscription. 
4. Then, select the subscribe instance and database.
5. Also, select and configure the distribution agent security, subscription initialization, and the agent schedule. 
6. Complete the wizard to create the subscription.

Till here, we have created all three required components for transactional replication SQL Server. Now, it is time to start and verify the replication process. 

Initiate and Verify the Replication

To verify the process, confirm the following things:

• The configured snapshot agent is running and creating the snapshot files without any issues. 
• The Distributor agent is updating the changes from the publisher to the subscriber. 

To check and verify the replication process, follow the given steps:

1. Right-click on replication.
2. Select and launch the Replication Monitor to efficiently monitor the complete process. 

This is the complete process for how transactional replication SQL Server can be executed. If the users wish to use this method for any of the given use cases, they can follow up with these steps and can benefit from the transactional replication process. 

Conclusion

With the help of this thorough write-up, we have understood and learned the entire process of transactional replication SQL Server. We have also discussed thoroughly the steps to implement the process smoothly and seamlessly.