Lachesis : robust database storage management based on device-specific performance characteristics

Abstract: "Database systems work hard to tune I/O performance, but they do not always achieve the full performance potential of modern disk drives. Their abstracted view of storage components hides useful device-specific characteristics, such as disk track boundaries and advanced built-in firmware algorithms. This paper presents a new storage manager architecture, called Lachesis, that exploits a few observable device-specific characteristics to achieve more robust performance. Most notably, it enables efficiency nearly equivalent to sequential streaming even in the presence of competing I/O traffic. With automatic adaptation to device characteristics, Lachesis simplifies manual configuration and restores optimizer assumptions about the relative costs of different access patterns expressed in query plans. Based on expriments with both IBM DB2 and an implementation inside the Shore storage manager, Lachesis improves performance of TPC-H queries on average by 10% when running on dedicated hardware. More importantly, it speeds up TPC-H by up to 3X when running concurrently with an OLTP workload, which is simultaneously improved by 7%.