Redis 从入门到精通（十）：高级特性专题 —— Stream、Bitmap、HyperLogLog、Geo 与 Bloom 过滤器
一、Stream：Redis 的轻量级消息队列
1.1 Stream 的诞生背景
Redis 原本有 Pub/Sub 作为消息通道，但它有致命缺陷：消息不持久化，消费者离线期间的消息直接丢失。Redis 5.0 引入 Stream 就是为了解决这个问题——它借鉴了 Kafka 的分区+消费者组设计，提供了持久化的、支持 ACK 的消息队列能力。
1.2 Stream 核心概念
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