Simulating a Search Engine Service focusing on Network Performance

Abstract

Large-scale computer systems like Search Engines provide services to thousands of users, and their user demand can change suddenly. This unstable demand impacts sensitively to the service components (like network and hosts). The system should be able to address unexpected scenarios; otherwise, users would be forced to leave the service. Creating tests scenarios is an alternative to deal with this variable workload before implementing new configuration in the system. However, the complexity and size of the system are a huge constraint to create physical models. Simulation can help to test promising models of search engines. In this paper we propose a method to model a Search Engine Service (SES) on small scale to analyze the impact of different configurations. We model the interaction of a typical search engine with three main components: a Front Service (FS), a Cache Service (CS) and an Index service (IS). The FS takes as input a query of user and search into a database with the support of a CS to improve the performance of the system. The proposed model processes a trace file from a real SES and based on the dependency relation among the messages, services and queries, it is modeled the full functionality of the SES. The output is, on one hand a simulated trace file to compare the model with the real system and on the other hand statistics about performance. The simulation allow us to test configurations of FS, CS, and IS, which can be unlikely in the real system.