  Memory disaggregation can potentially allow memory-optimized range indexes
such as B+-trees to scale beyond one machine while attaining high hardware
utilization and low cost. Designing scalable indexes on disaggregated memory,
however, is challenging due to rudimentary caching, unprincipled offloading and
excessive inconsistency among servers.
  This paper proposes DEX, a new scalable B+-tree for memory disaggregation.
DEX includes a set of techniques to reduce remote accesses, including logical
partitioning, lightweight caching and cost-aware offloading. Our evaluation
shows that DEX can outperform the state-of-the-art by 1.7--56.3X, and the
advantage remains under various setups, such as cache size and skewness.
