LuTiao Programming

Jul 24, 2026 · Backend Development

Why Scheduled Tasks Run Multiple Times in a Cluster – The Real Issue Isn’t Quartz but Poor Architecture

When a Java application that uses Spring’s @Scheduled moves from a single server to a cluster, the same job may execute on every node, causing duplicate orders, messages, and data; the article explains why this happens, examines common lock‑based fixes and their pitfalls, and proposes a robust, idempotent, sharded task architecture.