Software as a service is becoming an increasingly common software delivery model but causes a challenge to service providers related to the design of both applications and data management. Multi-tenant databases allow them to reduce operating costs by leveraging economies of scale. Load balancing of multi-tenant databases with shared-nothing architectures can be done in different tiers of the software stack. In this article, different approaches for this purpose are discussed and the proxy server H2 Proxy is presented. H2 Proxy can be deployed in different tiers and routes tenant requests to database servers corresponding to a tenant placement policy which is changeable at runtime. This article gives an overview of its implementation and demonstrates its efficient routing according to test results.
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