The paper entitled "MQJoin: Efficient Shared Execution of Main-memory Joins" by Darko Makreshanski, Georgios Giannikis, Gustavo Alonso and Donald Kossmann has been selected as one of the Best Papers of VLDB 2016.
Database architectures typically process queries one-at-a-time, ex- ecuting concurrent queries in independent execution contexts. Of- ten, such a design leads to unpredictable performance and poor scalability. One approach to circumvent the problem is to take advantage of sharing opportunities across concurrently running queries. In this paper we propose Many-Query Join (MQJoin), a novel method for sharing the execution of a join that can effi- ciently deal with hundreds of concurrent queries.
This is achieved by minimizing redundant work and making efficient use of main- memory bandwidth and multi-core architectures. Compared to ex- isting proposals, MQJoin is able to efficiently handle larger work- loads regardless of the schema by exploiting more sharing oppor- tunities. We also compared MQJoin to two commercial main- memory column-store databases. For a TPC-H based workload, we show that MQJoin provides 2-5x higher throughput with signif- icantly more stable response times.