Latch-free Synchronization in Database Systems: Silver Bullet or Fool's Gold?

Recent research on multi-core database architectures has made the argument that, when possible, database systems should abandon the use of latches in favor of latch-free algorithms. Latch-based algorithms are thought to scale poorly due to their use of synchronization based on mutual exclusion. In contrast, latch-free algorithms make strong theoretical guarantees which ensure that the progress of a thread is never impeded due to the delay or failure of other threads. In this paper, we analyze the various factors that influence the performance and scalability of latch-free and latch-based algorithms, and perform a microbenchmark evaluation of latch-free and latch-based synchronization algorithms. Our findings indicate that the argument for latch-free algorithms’ superior scalability is far more nuanced than the current state-of-the-art in multi-core database architectures suggests.