After writing my last post on MongoDB, I attended a meet-up at the Mozilla office in San Francisco to hear the tale of a real company in the process of migrating from Microsoft SQL Server to MongoDB.
The company, Harmonic, sells enterprise software for managing workflows around video. Videos come in, go through checks, conversions, and other processing, and get distributed over multiple channels. (Ok, vast simplification, but that’s the gist of it.) The architecture consists of a GUI and other management tools on the front-end, a set of services for processing videos on the back-end, and a workflow engine that orchestrates the process. The workflow engine stores its state in a database, and that database had been Microsoft SQL Server.
The marketing staff demanded that engineering reduce complexity for customers, increase scalability, and keep costs low. Nick Vicars-Harris, who manages the Harmonic engineering team, experimented with MongoDB. It took just a few days to tweak the data layer, written in C# and utilizing LINQ, to work with MongoDB rather than SQL Server. According to Vicars-Harris, Harmonic removed code that had been needed for object relational mapping, refactored, and produced more intuitive code. Rather than normalizing workflow state across over twenty tables, Harmonic could now store each job and its related tasks in a single document. In addition to removing complexity, the solution passed the test for scalability.
Harmonics also took advantage of the MongoDB simplified deployment model to create what Vicars-Harris calls smart nodes, nodes that communicate with each other and self-configure, a solution that met the requirements for simplified deployment and maintenance.
After listening to the presentation, I was impressed with the ease of transition from SQL to NoSQL. Clearly, the workflow use case fits in well with document-oriented databases.
Jim Downey 
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