Internal

Redis is single threaded, actually, Redis is kinda single threaded, since there are threads in order to perform certain slow operations on disk.

Redis 是单线程的, 但事实上, Redis 只是 近似 单线程, Redis 利用了多线程来处理一些慢操作

In a single-threaded server the easy way to make operations non-blocking is to do things incrementally instead of stopping the world. LRU eviction and keys expires are two obvious examples.

在一个单线程服务上, 实现非阻塞最简单的方式就是增量式的执行操作, 而不是 stop the world (姑且翻译成: 让世界停止转动). LRU eviction 和 key expires 是二个典型的例子, dict hash resize 也是增量式实现的.

Redis Object

typedef struct redisObject {
    unsigned type:4;
    unsigned encoding:4;

    /* LRU time (relative to server.lruclock) or
     * LFU data (least significant 8 bits frequency
     * and most significant 16 bits decreas time). */
    unsigned lru:LRU_BITS;
    int refcount;
    void *ptr;
} robj;

• Anatomy of a Redis command

Protocol

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