This article explains why running only one Spring Boot instance per server is essential for stability and data integrity, and presents four practical techniques—file locks, FileChannel locks, port binding, and IPC sockets—complete with code samples to prevent duplicate startups.
This article explains how to handle flash‑sale (seckill) scenarios in PHP by reducing database pressure with caching, preventing stock oversell using row locks, transactions, file locks, and Redis queues, and provides complete code examples for each technique.
This article explains a real-world case where storing WeChat access tokens in a JSON file caused race conditions, analyzes the root cause, and demonstrates how to use PHP's flock() function with proper locking to safely read and write the token, including sample code.
This article explains the principles behind NFS file‑lock state view consistency, covering NFSv4's stateful design, the SeqId mechanism, SunRPC handling of duplicate requests, and how signal interruptions are managed to keep client and server lock views synchronized.
This tutorial explains how to use Java NIO's FileChannel to acquire exclusive and shared file locks, covering lock types, required channel modes, code examples for FileOutputStream, RandomAccessFile, and FileInputStream, and discusses platform-specific considerations and common exceptions.
This article explains MMKV's design, the challenges of adding multi‑process support on Android, the IPC architecture choices, file‑lock synchronization mechanisms, and performance comparisons with SharedPreferences and SQLite.
This article demonstrates how cron jobs can overlap when a script runs longer than its schedule, and shows how to use Linux's flock file lock to ensure only one instance of the script runs at a time, preventing execution conflicts.
