Merge‑On‑Read defers writes to background, cutting rewrite amplification
Merge‑On‑Read (MOR) shifts the cost of merging updates from the write path to background processing, avoiding the costly copy‑on‑write rewrites of whole columnar files. By appending changes to log files and compacting later, MOR enables high‑frequency row‑level mutations while keeping cheap object‑storage scans efficient, a design first introduced by Apache Hudi.