Performance Driven Database Design for Scalable Web Applications

Scaling up web applications requires distribution of load across multiple application servers and across multiple database servers. Distributing load across multiple application servers is fairly straightforward; however distributing load (select and UDI queries) across multiple database servers is more complex because of the synchronization requirements for multiple copies of the data. Different techniques have been investigated for data placement across multiple database servers, such as replication, partitioning and de-normalization. In this paper, we describe our architecture that utilizes these data placement techniques for determining the best possible layout of data. Our solution is general, and other data placement techniques can be integrated within our system. Once the data is laid out on the different database servers, our efficient query router routes the queries to the appropriate database server/(s). Our query router maintains multiple connections for a database server so that many queries are executed simultaneously on a database server, thus increasing the utilization of each database server. Our query router also implements a locking mechanism to ensure that the queries on a database server are executed in order. We have implemented our solutions in our system, that we call SIPD (System for Intelligent Placement of Data). Preliminary experimental results illustrate the significant performance benefits achievable by our system.