Redis

Overview EVAL and EVALSHA are Redis commands used to execute Lua scripts within the Redis server. They differ primarily in how they handle script loading and execution: EVAL: This command takes the Lua script as an argument. Redis parses and hashes the script every time EVAL is called. This adds overhead, especially for frequently executed scripts. EVALSHA: This command takes the SHA1 hash of the Lua script as an argument. Redis retrieves the script from its internal cache using this hash. [Read More]

Redlock Algorithm: Distributed Lock Management Introduction The Redlock algorithm is a distributed lock algorithm designed to provide a reliable locking mechanism in distributed systems. It was proposed by the Redis community as a way to implement distributed locks using multiple independent Redis instances. Purpose The main purpose of the Redlock algorithm is to ensure that: Mutual exclusion is guaranteed Deadlock free operation is possible Fault tolerance is achieved up to a certain degree Algorithm Overview The Redlock algorithm uses multiple Redis instances (typically 5) to achieve consensus on lock acquisition and release. [Read More]

Comprehensive Technical Analysis: Redis, Pika, and Codis Introduction In the realm of distributed data storage and caching systems, Redis, Pika, and Codis represent three distinct approaches to solving scalability, persistence, and performance challenges. This comprehensive analysis delves deep into the architectures, features, and use cases of these systems, providing detailed code examples and visual representations to facilitate a thorough understanding. Redis Redis (Remote Dictionary Server) is an open-source, in-memory data structure store that has become a cornerstone in modern application architectures. [Read More]

A comprehensive guide to troubleshooting Redis performance issues 1. Introduction Redis is renowned for its high performance, capable of handling 100,000 operations per second. However, users may encounter unexpected latency issues in various scenarios: Same commands sometimes fast, sometimes slow Simple operations like SET and DEL taking unexpectedly long Temporary slowdowns that resolve themselves Sudden performance degradation after long periods of stability This comprehensive guide (approximately 20,000 words) aims to provide a thorough troubleshooting approach for Redis performance issues. [Read More]

What is Redis pipelining? Pipelining is a technique used to send multiple commands to the server without waiting for the replies, and then reading the replies in a single step. Explain Redis transactions. Redis transactions allow the execution of a group of commands in a single step. Key properties: All commands in a transaction are serialized and executed sequentially Either all or none of the commands are processed Redis transactions are atomic How does Redis implement master-slave replication? [Read More]