Phil Bernstein

Latch-Free Index Trees Scale by Choosing a Worker Before Reconstruction

David B. Lomet, a retired Microsoft Research researcher, argues that latch-free index trees can still lose scalability when competing threads perform the same expensive structural work before one wins a compare-and-swap. In his talk on the Bw-tree, he presents latch-free notices as an early way to select a worker, protect the state being changed and direct updates while consolidation, splits or merges proceed. The aim is to avoid redundant reconstruction without stopping other threads from using the index.