Domain Specific Continuous Queries Implemented using Database Management Systems

Abstract

We present an alternative to Continuous Queries, these are queries that deliver streams of data to clients as opposed to common queries which only respond with a single response. We define Domain Specific Continuous Queries as a query that, apart from an initial response with the matching set of records, streams all updates affecting the query. We implement this definition of a Continuous Query for a specific domain where an existing solution and problem definition already exists. The new implementation uses classic query-response database systems to supply the initial response. A persistent data structure containing the full state of the data is kept in memory, which allows our prototype to deduce which queries an incoming update affects. The new implementation is on par with the existing solution’s feature set and greatly outperforms it for our metrics. Especially for initial response latency.