Pragmatic Programming Techniques: Scalable System Design Patterns

Pragmatic Programming Techniques: Scalable System Design Patterns

Load Balancer

In this model, there is a dispatcher that determines which worker instance will handle the request based on different policies. The application should best be "stateless" so any worker instance can handle the request.

This pattern is deployed in almost every medium to large web site setup.



Scatter and Gather

In this model, the dispatcher multicast the request to all workers of the pool. Each worker will compute a local result and send it back to the dispatcher, who will consolidate them into a single response and then send back to the client.

This pattern is used in Search engines like Yahoo, Google to handle user's keyword search request ... etc.

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