Copy-on-Write

This article explains how copy‑on‑write (COW) B‑trees work, why they improve concurrency, and what trade‑offs they introduce for modern database engines.

Copy‑on‑write lets multiple processes reference the same memory until a write occurs, dramatically reducing duplication and improving performance. This post explains the mechanics, real‑world implementations, and trade‑offs.

Copy‑on‑write B‑trees let databases capture point‑in‑time snapshots without blocking writers, enabling true atomic reads and fast recovery.

Copy‑on‑write B‑trees let databases take point‑in‑time snapshots instantly, without blocking writes. This post explains the mechanics, trade‑offs, and real‑world implementations.

Copy‑on‑write avoids costly memory allocation by sharing data until a write occurs, dramatically improving throughput in many systems.