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Single-System Locks In single-system architectures, locks like ReentrantLock are effective for controlling concurrent access within a single JVM. However, when multiple instances of an application are running behind a load balancer, these locks become ineffective as each instance operates independently. Testing with JMeter to simulate high co ...

RabbitMQ Setup with Dead Letter Handling To handle timed‑order expiry, a RabbitMQ infrastructure consisting of a direct exchange, a durable queue, and a dedicated dead‑letter exchange (DLX) is defined. The queue is declared with arguments that route expired (unconsumed) messages to the DLX after a configured TTL. Below is the Spring configurati ...

Redis-Based Distributed Locking with Redisson Distributed systems often require mechanisms to ensure that only one process or thread can access a shared resource at a time across different service instances. Redis, a popular in-memory data store, can be effectively leveraged for this purpose, particularly through libraries like Redisson. Maven ...

Overview Redisson is an in-memory data grid built on top of Redis that provides distributed Java objects and services. Beyond standard Redis operations, it offers a rich set of distributed structures including Queue, Lock, AtomicLong, CountDownLatch, Publish/Subscribe, and ExecutorService. Redisson abstracts away the complexities of Redis, allo ...

Redis Lock Vulnearbility Analysis Asynchronous replication creates critical vulnerabilities during failover scenarios: Timeline: 1. Client A acquires lock on master (SET resource_id unique_val NX EX 30) 2. Lock replication to replica delayed (ms to hundreds of ms) 3. Master fails, sentinel triggers failover (3-10 seconds) 4. Replica becomes new ...

Solving Cache Penetration Consider a typical product lookup service: public Product getProductById(Long id) { Product product = cache.get(id); if (product != null) { return product; } product = database.query(id); if (product != null) { cache.put(id, product); } return product; } If a product ID ...