At its foundation, CockroachDB depends on a key-value storage engine called Pebble. In CockroachDB v25.4, the storage team introduced value separation within Pebble: an optimization that improves compaction efficiency for many workloads. Value separation increases the throughput of the core of CockroachDB, the storage engine, by up to ~50%, depending on the workload, through algorithmic improvements. It reduces redundant I/O, reducing cost-to-serve at scale. We’ll look at how Pebble represents data today, what’s changed, and how that translates to database efficiency.

Annie Pompa

January 13, 2026