16.1. Replication Overview

SQL Server replication closely resembles the magazine publishing industry, so we'll use that analogy to explain its overall architecture. Consider National Geographic. The starting point is the large pool of journalists writing articles. From all the available articles, the editor picks which ones will be included in the current month's magazine. The selected set of articles is then published in a publication. Once a monthly publication is printed, it is shipped out via various distribution channels to subscribers all over the world.

In SQL Server replication, similar terminology is used. The pool from which a publication is formed can be considered a database. Each piece selected for publication is an article; it can be a table, a stored procedure, or another database object. Like a magazine publisher, replication also needs a distributor to deliver publications, keep track of delivery status, and maintain a history of synchronization to maintain data consistency. Depending on the kind of replication model you choose, articles from a publication can be stored as files in a folder to which both publisher and subscriber(s) have access, or transactions within articles can be committed on subscribers synchronously or asynchronously. Regardless of how publications are delivered, replication always needs a distributor database to keep track of delivery status. Depending on the capacity of the publication server, the distributor database can be on the same ...

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