Tigon: A Distributed Database for a CXL Pod

Building efficient distributed transactional databases remains a challenging problem despite decades of research. Existing distributed databases synchronize cross-host concurrent data accesses over a network, which requires numerous message exchanges and introduces performance overhead.

We describe Tigon, the first distributed in-memory database that synchronizes concurrent cross-host data accesses using atomic operations on CXL memory. Using CXL memory is more efficient than network-based approaches, but Tigon's design must address CXL's higher latency and lower bandwidth relative to local DRAM, as well as CXL's limited hardware support for cross-host cache coherence. For TPC-C and a variant of YCSB, Tigon achieves up to 2.5× higher throughput compared with two optimized shared-nothing databases that use CXL memory as a transport and up to 18.5× higher throughput compared with an RDMA-based distributed database.