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Describe in brief working of Replication.What is Replication?
- It is a set of technologies for copying and distributing data and database objects from one database to another.
- It is the process of copying or moving data between databases on the same or different servers.
- It is a set of technologies for copying and distributing data.
- You can distribute data to different locations and to remote using with the replication.
- It is used in server-to-server scenarios that require high throughput.
- It helps to improve scalability and availability.
Working of Replication:
At first data and object is synchronized between publisher and subscribers. The snapshot is created on the publisher and transmitted to subscribers. All the subsequent changes on the publisher are stored in a distribution database. The subscriber receives the data either using push or pull mechanism as configured from the distribution database.
Types of Replication:
1. Transactional replication
2. Merge replication
3. Snapshot replication
1. Transactional replication:
- It starts with a snapshot of the publication database objects and data.
- It is used in server-to-server scenarios that require high throughput.
- It improves scalability and availability, data warehousing and reporting.
- Integrating data from multiple sites.
2. Merge replication:
- It is designed for mobile applications or distributed server applications that have possible data conflicts.
- It allows various sites to work autonomously and later merge updates into a single.
- It is implemented by the SQL Server Snapshot Agent and Merge Agent.
- Merge replication merges incremental data changes that occurred at the publisher or subscribers after the initial snapshot was created.
3. Snapshot replication:
- It is used to provide the initial data set for transactional and merge replication.
- It can also be used when complete refreshes of data are appropriate.
- It distributes data exactly as it appears at a specific moment in time and does not monitor for updates to the data.
- It is most appropriate when data changes are substantial but infrequent.
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