## redis

Redis是一个使用ANSI C编写的开源、支持网络、基于内存、可持久性的键值对存储数据库。
Redis是最流行的键值对存储数据库。

- 官网: <https://redis.io>
- 源码: <http://download.redis.io/releases/redis-4.0.9.tar.gz>
- 文档: <https://redis.io/documentation>
- 开源: <https://github.com/antirez/redis/tree/4.0>

## 源码安装
```
$ wget http://download.redis.io/releases/redis-4.0.11.tar.gz
$ tar xzf redis-4.0.11.tar.gz && cd redis-4.0.11 && make
```
#### 启动服务端
```
$ src/redis-servce
...
```
#### 启动客户端
```
$ src/redis-cli
127.0.0.1:6379>
```
#### 基本命令
```
$ src/redis-cli
127.0.0.1:6379> set employee_name shy
OK
127.0.0.1:6379> get employee_name
"shy"
```
## 源码解析
### 数据结构
#### sds
#### dict
#### intset
#### adlist
#### ziplist
#### geohash
#### geo

### 数据类型
#### string
#### list
#### hash
#### set
#### zset

### 数据存储
#### db
#### expire
#### notify
#### script
#### multi
#### sort

### 服务框架
#### server
#### config
#### module
#### ae
#### aof
#### rdb

### 服务集群
#### replication
#### sentinel
#### cluster
#### pubsub

### 应用场景
#### 数据缓存
#### 分布式锁
#### 计数统计
#### 消息队列

基本类型
```
typedef struct redisObject { // server.h:585
    unsigned type:4;
    unsigned encoding:4;
    unsigned lru:LRU_BITS; /* LRU time (relative to global lru_clock) or
                            * LFU data (least significant 8 bits frequency
                            * and most significant 16 bits access time). */
    int refcount;
    void *ptr;
} robj;
```
```
typedef struct redisDb { // server.h:611
    dict *dict;                 /* The keyspace for this DB */
    dict *expires;              /* Timeout of keys with a timeout set */
    dict *blocking_keys;        /* Keys with clients waiting for data (BLPOP)*/
    dict *ready_keys;           /* Blocked keys that received a PUSH */
    dict *watched_keys;         /* WATCHED keys for MULTI/EXEC CAS */
    int id;                     /* Database ID */
    long long avg_ttl;          /* Average TTL, just for stats */
} redisDb;

struct redisServer { // server.h:874
    ...
    redisDb *db;
    ...
    int dbnum;                      /* Total number of configured DBs */
    ...
}
```


## 基本类型
### 字符串sds
```
struct __attribute__ ((__packed__)) sdshdr64 { // sds.h:68
    uint64_t len; /* used */
    uint64_t alloc; /* excluding the header and null terminator */
    unsigned char flags; /* 3 lsb of type, 5 unused bits */
    char buf[];
};
```

### 双链表adlist
```
typedef struct listNode { // adlist.h
    struct listNode *prev;
    struct listNode *next;
    void *value;
} listNode;

typedef struct list {
    listNode *head;
    listNode *tail;
    void *(*dup)(void *ptr);
    void (*free)(void *ptr);
    int (*match)(void *ptr, void *key);
    unsigned long len;
} list;
```

```
struct redisCommand redisCommandTable[] = {
}
```

### 哈希表dict
```
typedef struct dictEntry { // dict.h
    void *key;
    union {
        void *val;
        uint64_t u64;
        int64_t s64;
        double d;
    } v;
    struct dictEntry *next;
} dictEntry;

typedef struct dictType {
    uint64_t (*hashFunction)(const void *key);
    void *(*keyDup)(void *privdata, const void *key);
    void *(*valDup)(void *privdata, const void *obj);
    int (*keyCompare)(void *privdata, const void *key1, const void *key2);
    void (*keyDestructor)(void *privdata, void *key);
    void (*valDestructor)(void *privdata, void *obj);
} dictType;

/* This is our hash table structure. Every dictionary has two of this as we
 * implement incremental rehashing, for the old to the new table. */
typedef struct dictht {
    dictEntry **table;
    unsigned long size;
    unsigned long sizemask;
    unsigned long used;
} dictht;

typedef struct dict {
    dictType *type;
    void *privdata;
    dictht ht[2];
    long rehashidx; /* rehashing not in progress if rehashidx == -1 */
    unsigned long iterators; /* number of iterators currently running */
} dict;
```

### 跳跃表zskiplist
```
zskiplistNode { // server.h
    sds ele;
    double score;
    struct zskiplistNode *backward;
    struct zskiplistLevel {
        struct zskiplistNode *forward;
        unsigned int span;
    } level[];
} zskiplistNode;

typedef struct zskiplist {
    struct zskiplistNode *header, *tail;
    unsigned long length;
    int level;
} zskiplist;
```

### 整数集合intset
```
typedef struct intset { // intset.h
    uint32_t encoding;
    uint32_t length;
    int8_t contents[];
} intset;
```

## 源码解析
### 目录解析

- COPYING 版权文件
- README.md 说明文档
- Makefile make文件
- deps/ 依赖库
- src/ 源码目录
- tests/ 测试脚本
- utils/ 工具脚本
- redis.conf 配置文件
- sentinel.conf 配置文件

BUGS
INSTALL
MANIFESTO
CONTRIBUTING
00-RELEASENOTES

dump.rdb
runtest
runtest-cluster
runtest-sentinel

### 代码解析
```
server.h //服务端
  redisObject:struct //数据结构
    type:unsigned
    encoding:unsigned
    lru:unsigned
    refcount:int
    ptr:void*

server.c //服务端
  server: redisServer //服务端上下文
    pid: pid_t
    configfile: char*
    executable: char*
    exec_argv: char*
    commands: dict* //命令哈希表
    db: redisDb* //数据库
      dict: dict*
      expires: dict*
      blocking_keys: dict*
      ready_keys: dict*
      watched_keys: dict*
      id: int
      avg_ttl: long long
    clients: list/client //客户端连接
      id: uint64
      fd: int
      db: redisDb*
      name: robj*
      querybuf: sds
      pending_querybuf: sds
      argc: int
      argv: robj**
      cmd: redisCommand*
      reply: list*

  redisCommandTable: redisCommand //命令列表
    "get": getCommand
    "set": setCommand
      setGenericCommand(c)
        setKey(c->db,k,v)
          lookupKeyWrite(db,k)
            lookupKey(db,k)
              dictFind(db->dict,k->ptr)
          dbAdd(db,k,v)
            dictAdd(db->dict,k->ptr,v)
          dbOverwrite(db,k,v)
            dictReplace(db->dict,k->ptr,v)
        addReply(c, o)
          prepareClientToWrite(c)
            listAddNodeHead(server.clients_pending_write, c)
          _addReplyToBuffer(c, o)
            c->buf
            c->bufpos
          _addReplyObjecToList(c, o)
            listAddNodeTail(c->reply, sdsdup(o->ptr))

  serverLog() //输出日志
    server.verbosity
    serverLogRaw()
      server.logfile
  ustime()
  mstime()


  main() //程序入口
    initServerConfig() //初始化server
      populateCommandTable() //加载命令列表
        server.commands = redisCommandTable
    loadServerConfig() //加载配置文件
    initServer() //
      aeCreateFileEvent()
    loadDataFromDisk()
    aeMain():ae.c //事件循环
      el->beforesleep()
        handleClientsWithPendingWrites() //返回命令执行结果
          writeToClient(c)
            write(c->buf)
      aeProcessEvents(el):ae.c
        aeApiPoll()
        el->aftersleep()
        fe->rfileProc()/acceptTcpHandler() //添加网络监听事件
          anetTcpAccept()
          acceptCommonHandler()
            createClient()
              aeCreateFileEvent()/readQueryFromClient(el) //添加读取数据事件
                read(c->querybuf)
                processInputBuffer(c)
                  processInlineBuffer() //解析客户端命令
                    c->argv[i]=createObject()
                  processCommand(c) //执行客户端命令
                    c->cmd=lookupCommand()
                      dictFetchValue(server.commands)
                    call(c)
                      c->cmd->proc(c)/setCommand(c)

      fe->wfileProc()
      fe->rfileProc()
      processTimeEvnts()

db.c
  setKey()
t_string.c
  setGenericCommand()
  setCommand()

t_hash.c

t_list.c
t_set.c
t_zset.c

networking.c //
  createClient()

adlist.h //双链表
aslist.c
ae.h //事件循环
ae.c
ae_epoll.c
ae_evport.c
ae_kqueue.c
ae_select.c
anet.h //网络接口
anet.c
aof.c
asciilogo.h
atomicvar.h
bio.h
bio.c
bitops.c
blocked.c
childinfo.c
cluster.h
cluster.c
config.h
config.c
crc16.c
crc64.c
crc64.h
debug.c
debugmacro.h
defrag.c
dict.h
dict.c
edianconv.c
edianconv.h
evict.c
expire.c
fmacros.h
geo.c
geo.h
geohash.h
geohash.c
geohash_helper.h
geohash_helper.c
help.h
hyperloglog.c
intset.h
intset.c
latency.h
latency.c
lazyfree.c
lzf.h
lzf_c.h
lzf_d.h
lzfP.h
memtest.c
module.c
multi.c
networking.c
notify.c
object.c
pqsort.c
pqsort.h
pubsub.c
quicklist.c
quicklist.h
rand.c
rand.h
rax.c
rax.h
rax.malloc.h
rdb.c
rdb.h
redis-benchmark.c
redis-cli.c
redisassert.h
redismodule.h
release.c
release.h
replication.c
rio.h
rio.c
scripting.c
sds.h
sds.c
sdsalloc.h
sentinel.c
setproctitle.c
sha1.h
sha1.c
siphash.h
siphash.c
sort.c
sparkline.h
sparkline.c
syncio.c
testhelp.c
util.c
util.h
version.h
ziplist.h
ziplist.c
zipmap.c
zipmap.h
zmalloc.c
zmalloc.h





dict.c //
  dict:struct
    type:dictType
	privdata:void*
    ht:dictht[2]
      table:dictEntry**
        key:void*
        v:union
        next:void*
      size:long
      sizemask:long
      used:long
    rehashidx:long
    iterators:long
  
zmalloc.c //内存管理
  zmalloc()
  zcalloc()
  zrealloc()
  zmalloc_size()
  zfree()
  zstrdup()
```

### server.h
#### struct redisServer
#### struct client
#### struct redisObject
### networking.c
### db.c
### object.c
### t_hash.c
### t_list.c
### t_set.c
### t_string.c
### t_zset.c
### ae.c 事件循环