Privacy policy. Install replication when you install SQL Server, or when you modify an existing instance. After replication components are installed, you must configure the server before you can use replication.
If you install replication components when you modify an existing instance of SQL Server, you must stop and restart SQL Server Agent after the installation is completed.
This action helps ensure that SQL Server Agent recognizes the replication agent subsystems and can call replication agents from job steps. Snapshot replication is used to replicate data precisely as it appears at the moment when the database snapshot was created.
This replication type can be used when data is changed infrequently; when it is not critical to have a database replica that is older than a master database; or a large volume of changes is made within a short period of time. No change tracking is performed for snapshot replication. For example, snapshot replication can be used when exchange rates or price lists are updated once per day and must be distributed from a main server to servers in branch offices.
Transactional replication is the periodic automated replication when the data is distributed from a master database to a database replica in real-time or near-real-time. Transactional replication is more complex than snapshot replication. Not only is the final state of a database replicated, all made transactions are also replicated, which makes it possible to monitor the entire transaction history on the database replica.
In the beginning of the transactional replication process, a snapshot is applied to the Subscriber and then data is continuously transferred from a master database to a database replica after being changed. Transactional replication is widely used as one-way replication. Peer-to-peer replication is used to replicate database data to multiple subscribers at the same time.
Changes can be made on any of the database servers. Changes are propagated to all database servers. Peer-to-peer replication can help scale out an application that uses a database. The main working principle is based on transactional replication. Below you can see how MS SQL Server peer-to-peer replication can be used between database servers that are distributed across the globe.
Merge replication is a type of bidirectional replication that is usually used in server-to-client environments for synchronizing data across database servers when they cannot be connected continuously. When the network connection is established between both database servers, merge replication agents detect changes made on both databases and modify databases to synchronize and update their state. Merge replication is similar to transactional replication, but data is replicated from the Publisher to the Subscriber and inversely.
For example, merge replication can be used by multiple peer stores that work with a shared warehouse. Each store is permitted to change the information in the warehouse database and at the same time all stores must have the updated state of their databases after the shipment of goods or delivery of supplies to the warehouse. Merge replication can be used in cases where the updated information must be available for the main or central database and branch databases simultaneously.
For example, if you want to configure MS SQL transactional replication, you can use the second database server where the Subscriber is configured of a version within two versions of the source database server on which the Publisher is configured.
If you are going to configure MS SQL replication for the first time, it is recommended that you practice in a test environment, for example, configuring replication in SQL servers running on virtual machines. You have to configure the servers before you can start database replication. Two Windows Server machines used in this example are not in Active Directory. If you use Active Directory, you can create the mssql user on the domain controller. You can start this service manually, but it is better co configure this service to start automatically after Windows boot.
Right click Logins and select New Login. Select Windows authentication. Click Search , then hit Check names to confirm and hit OK twice to save the settings. In the Members page click Add , enter the name of your user mssql and click Check names. The AdventureWorks database is used as a sample database in this example. Copy the AdventureWorks Import a sample database.
Select the needed. You can import the database from a backup on the second machine, where the database replica will be running. This approach allows you to reduce network traffic because your replication will start with replicating the changes to the existing database, but not copying the entire database data to an empty database.
Finally, we have:. Right click or double click mssql user and select Properties. On the User Mapping page, select users mapped to this login and tick the AdventureWorks database checkbox select AdventureWorksr on the second server accordingly. Configuring replication in a graphic mode is the most convenient method. To better understand how to configure replication in SQL server, there are screenshots to demonstrate the workflow.
Transactional database replication is explained in this example because it is one of the most used MS SQL Server replication types.
Distribution can be used for multiple publishers and subscribers. In this example, Distribution is configured on the main server on which a source database is stored. Hit Next for each step in the Wizard to continue. Snapshot Folder. You can leave the default path here. A snapshot is needed for initializing replication. Make sure that there is enough free space on the disk where your snapshot directory is located. The amount of free space must correspond to at least the size of a replicated database.
Distribution Database. Enter the distribution database name. You can leave the default name distribution and folders for the distribution database file and log file. Tick the checkbox near the distribution database name on the primary MS SQL Server instance that hosts a source database that will be replicated. Wizard Actions.
Tick the Configure distribution checkbox to configure distribution during the final step of the wizard. In this example, we will not generate a script file to be executed later.
Distribution Database: A database which contains all the Replication commands. Let us now begin with the Configuring of the Transactional Replication. There are 3 steps involved for Configuring the Transactional Replication: 1. Configuring the Distribution Database. Creating the publisher. Creating the subscriber. Configuring the Distribution Database 1. Right Click on the Replication node and Select Configure Distribution as shown in the screen capture below: 3.
A new window appears on the screen as shown in the screen capture below: 4. A new window appears as shown in the screen capture below: 7. A new window appears on the screen as shown in the screen capture below: As you can see in the above screen capture, you are asked where the Snapshot folder should reside on the Server. A new window appears as shown in the screen capture below: As you can see in the above screen capture, it displays information such as what will be the distribution database name, the location where the data and the log file will reside.
A new window appears as shown in the screen capture below: Click on the Finish button as shown in the screen capture below: In order to confirm it just expand the System Database node and you shall be able to view the distribution database, please refer the screen capture below: Creating the Publisher The following steps need to be followed while creating the publisher.
Right Click on Local Publications and select New Publications, please refer the screen capture below: 2. Recently we had an issue in our Production environment, on the Reporting Database Server the Transactional Replication procedure was being blocked due to execution Replication Without Creating a Snapshot. In replication, the standard way of creating a publisher is to create a publication with a snapshot which is what all the documentation recommends.
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