1Citywire – Oct 2012For internal use only - no part of this report can be distributed to affiliate, subsidiary, parent or associated companies, to third parties or publicised in any way.

Migrating from a scale-up relational database to a scale-out schema-less solution

The Company

• Founded in 1999 as a financial news website in the UK. Based in London

• Citywire is a growth company and today, we make money via online and print advertising, events and research across Europe and starting Q3, Lat. America and Asia

• At the start of 2012, we had thirteen people in the technology team

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Technology we use

• Windows Servers• ASP.NET• MS SQL Server 2008 R2• Vmware Virtualisation• NetApp Storage• Couchbase noSQL

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Where we were in 2011

• Rapid traffic growth• Time-outs• Server 500’s• Long loading times

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www.citywire.co.uk architecture

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Where were the problems?

• Complicated SQL leading to poor query performance

• Single SQL server overloaded at busy times• ASP.NET Memory caching is inefficient• Complicated DAL code and often business

logic in SQL

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Our codebase

• Technical Debt accrued over the years - Business logic all over the place, including in stored procedure

• ASP.NET Web Forms (with some MVC)• Synchronous messaging with WCF

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SQL Server

• Operational issues – single point of failure, maintenance jobs

• In team skills – we had no DBA, and our developers were strong in C# and ASP.NET

• Cost – every couple of years, we had been buying bigger and bigger servers

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ASP.NET Caching

• Consistency across web gardens and web farms

• ASP.NET Cache is lost when the worker process is restarted

• Cache size limitations, garbage collection, and large objects (http://www.simple-talk.com/dotnet/.net-framework/the-dangers-of-the-large-object-heap/)

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Our solution to the problem

• Commitment to separation of concerns, MVC, IoC, dependency injection, and AOP

• CDN for static content• A distributed caching solution

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How did we do it?

• Built a Couchbase (membase) cluster• AOP - MS Enterprise Library’s Policy Injection

Handler• IoC and Dependency Injection - Structuremap• Left our CMS and processes working off the

SQL Server

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Couchbase (Membase)

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What did it give us?

• Cache consistency across web farm and gardens

• Scalable cache size• But not resilience against single point of

failure for our main web site, we were only caching.

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Global Growth in 2012

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Architecting for 35 websites

• New codebase, with continued commitment to separation of concerns, MVC and IoC

• Asynchronous eventual consistency - NServiceBus

• Commitment to scaling out• Building a “single version of the truth” in the

form of schemaless documents stored in couchbase

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Schemaless documents

• JSON, we used the JSON.NET serialiser (http://json.codeplex.com/)

• Moved all business logic to move into the “publishing” tier• Asynchronous publishing via nService bus, and continue to also

go to SQL• Conventions for modifying

document fields forbackwards compatibility

• Developers can stay in theircomfort zone of C# and awayfrom SQL

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How we are doing it ….

• Using Couchbase 1.8.1 in production and Solr for search.

• Started by caching the newly designed documents using existing methods by building code to create the document through existing services

• Created async publishing integration points to couchbase leaving existing SQL based applications to function

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Publishing documents

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Thanks for listening

• Truc Chu• tchu@citywire.co.uk• http://www.linkedin.com/pub/truc-chu/

48/267/29b

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Citywire – Oct 2012For internal use only - no part of this report can be distributed to affiliate, subsidiary, parent or associated companies, to third parties or publicised in any way. 20