DBHUB: A Lightweight Middleware for Accessing Heterogeneous Database Systems

Traditional relational database management system (RDBMS) has the capability of full transaction processing but introduces the unnecessary overhead for dealing with the unstructured data in several big data scenarios. In contrast, the NoSQL systems can query the unstructured data with higher space-time efficiency, but most of them are lacking the function of transaction processing. To bridge the gap, we propose DBHUB, a lightweight middleware to combine the advantages of both sides. DBHUB provides the compatible APIs to upper applications and detects the received queries to extract the unstructured data automatically. In general, DBHUB handles the write query with RDBMS’s storage engine and serves the read query by NoSQL’s routine. We implement DBHUB in a practical system which including InnoDB in MySQL and MongoDB. The experimental results show that DBHUB can effectively accelerate the read query on unstructured data against the single RDBMS one. Meanwhile, the write query incurs mild overhead due to the write amplifications on heterogeneous databases.