struct redisServer {
    /* General */
    char *configfile;           /* Absolute config file path, or NULL */
    int hz;                     /* serverCron() calls frequency in hertz */
    redisDb *db;
    dict *commands;             /* Command table */
    dict *orig_commands;        /* Command table before command renaming. */
    aeEventLoop *el;
    unsigned lruclock:REDIS_LRU_BITS; /* Clock for LRU eviction */
    int shutdown_asap;          /* SHUTDOWN needed ASAP */
    int activerehashing;        /* Incremental rehash in serverCron() */
    char *requirepass;          /* Pass for AUTH command, or NULL */
    char *pidfile;              /* PID file path */
    int arch_bits;              /* 32 or 64 depending on sizeof(long) */
    int cronloops;              /* Number of times the cron function run */
    char runid[REDIS_RUN_ID_SIZE+1];  /* ID always different at every exec. */
    int sentinel_mode;          /* True if this instance is a Sentinel. */
    /* Networking */
    int port;                   /* TCP listening port */
    int tcp_backlog;            /* TCP listen() backlog */
    char *bindaddr[REDIS_BINDADDR_MAX]; /* Addresses we should bind to */
    int bindaddr_count;         /* Number of addresses in server.bindaddr[] */
    char *unixsocket;           /* UNIX socket path */
    mode_t unixsocketperm;      /* UNIX socket permission */
    int ipfd[REDIS_BINDADDR_MAX]; /* TCP socket file descriptors */
    int ipfd_count;             /* Used slots in ipfd[] */
    int sofd;                   /* Unix socket file descriptor */
    list *clients;              /* List of active clients */
    list *clients_to_close;     /* Clients to close asynchronously */
    list *slaves, *monitors;    /* List of slaves and MONITORs */
    redisClient *current_client; /* Current client, only used on crash report */
    char neterr[ANET_ERR_LEN];   /* Error buffer for anet.c */
    uint64_t next_client_id;    /* Next client unique ID. Incremental. */
    /* RDB / AOF loading information */
    int loading;                /* We are loading data from disk if true */
    off_t loading_total_bytes;
    off_t loading_loaded_bytes;
    time_t loading_start_time;
    off_t loading_process_events_interval_bytes;
    /* Fast pointers to often looked up command */
    struct redisCommand *delCommand, *multiCommand, *lpushCommand, *lpopCommand,
                        *rpopCommand;
    /* Fields used only for stats */
    time_t stat_starttime;          /* Server start time */
    long long stat_numcommands;     /* Number of processed commands */
    long long stat_numconnections;  /* Number of connections received */
    long long stat_expiredkeys;     /* Number of expired keys */
    long long stat_evictedkeys;     /* Number of evicted keys (maxmemory) */
    long long stat_keyspace_hits;   /* Number of successful lookups of keys */
    long long stat_keyspace_misses; /* Number of failed lookups of keys */
    size_t stat_peak_memory;        /* Max used memory record */
    long long stat_fork_time;       /* Time needed to perform latest fork() */
    double stat_fork_rate;          /* Fork rate in GB/sec. */
    long long stat_rejected_conn;   /* Clients rejected because of maxclients */
    long long stat_sync_full;       /* Number of full resyncs with slaves. */
    long long stat_sync_partial_ok; /* Number of accepted PSYNC requests. */
    long long stat_sync_partial_err;/* Number of unaccepted PSYNC requests. */
    list *slowlog;                  /* SLOWLOG list of commands */
    long long slowlog_entry_id;     /* SLOWLOG current entry ID */
    long long slowlog_log_slower_than; /* SLOWLOG time limit (to get logged) */
    unsigned long slowlog_max_len;     /* SLOWLOG max number of items logged */
    size_t resident_set_size;       /* RSS sampled in serverCron(). */
    /* The following two are used to track instantaneous "load" in terms
     * of operations per second. */
    long long ops_sec_last_sample_time; /* Timestamp of last sample (in ms) */
    long long ops_sec_last_sample_ops;  /* numcommands in last sample */
    long long ops_sec_samples[REDIS_OPS_SEC_SAMPLES];
    int ops_sec_idx;
    /* Configuration */
    int verbosity;                  /* Loglevel in redis.conf */
    int maxidletime;                /* Client timeout in seconds */
    int tcpkeepalive;               /* Set SO_KEEPALIVE if non-zero. */
    int active_expire_enabled;      /* Can be disabled for testing purposes. */
    size_t client_max_querybuf_len; /* Limit for client query buffer length */
    int dbnum;                      /* Total number of configured DBs */
    int daemonize;                  /* True if running as a daemon */
    clientBufferLimitsConfig client_obuf_limits[REDIS_CLIENT_TYPE_COUNT];
    /* AOF persistence */
    int aof_state;                  /* REDIS_AOF_(ON|OFF|WAIT_REWRITE) */
    int aof_fsync;                  /* Kind of fsync() policy */
    char *aof_filename;             /* Name of the AOF file */
    int aof_no_fsync_on_rewrite;    /* Don't fsync if a rewrite is in prog. */
    int aof_rewrite_perc;           /* Rewrite AOF if % growth is > M and... */
    off_t aof_rewrite_min_size;     /* the AOF file is at least N bytes. */
    off_t aof_rewrite_base_size;    /* AOF size on latest startup or rewrite. */
    off_t aof_current_size;         /* AOF current size. */
    int aof_rewrite_scheduled;      /* Rewrite once BGSAVE terminates. */
    pid_t aof_child_pid;            /* PID if rewriting process */
    list *aof_rewrite_buf_blocks;   /* Hold changes during an AOF rewrite. */
    sds aof_buf;      /* AOF buffer, written before entering the event loop */
    int aof_fd;       /* File descriptor of currently selected AOF file */
    int aof_selected_db; /* Currently selected DB in AOF */
    time_t aof_flush_postponed_start; /* UNIX time of postponed AOF flush */
    time_t aof_last_fsync;            /* UNIX time of last fsync() */
    time_t aof_rewrite_time_last;   /* Time used by last AOF rewrite run. */
    time_t aof_rewrite_time_start;  /* Current AOF rewrite start time. */
    int aof_lastbgrewrite_status;   /* REDIS_OK or REDIS_ERR */
    unsigned long aof_delayed_fsync;  /* delayed AOF fsync() counter */
    int aof_rewrite_incremental_fsync;/* fsync incrementally while rewriting? */
    int aof_last_write_status;      /* REDIS_OK or REDIS_ERR */
    int aof_last_write_errno;       /* Valid if aof_last_write_status is ERR */
    int aof_load_truncated;         /* Don't stop on unexpected AOF EOF. */
    /* RDB persistence */
    long long dirty;                /* Changes to DB from the last save */
    long long dirty_before_bgsave;  /* Used to restore dirty on failed BGSAVE */
    pid_t rdb_child_pid;            /* PID of RDB saving child */
    struct saveparam *saveparams;   /* Save points array for RDB */
    int saveparamslen;              /* Number of saving points */
    char *rdb_filename;             /* Name of RDB file */
    int rdb_compression;            /* Use compression in RDB? */
    int rdb_checksum;               /* Use RDB checksum? */
    time_t lastsave;                /* Unix time of last successful save */
    time_t lastbgsave_try;          /* Unix time of last attempted bgsave */
    time_t rdb_save_time_last;      /* Time used by last RDB save run. */
    time_t rdb_save_time_start;     /* Current RDB save start time. */
    int lastbgsave_status;          /* REDIS_OK or REDIS_ERR */
    int stop_writes_on_bgsave_err;  /* Don't allow writes if can't BGSAVE */
    /* Propagation of commands in AOF / replication */
    redisOpArray also_propagate;    /* Additional command to propagate. */
    /* Logging */
    char *logfile;                  /* Path of log file */
    int syslog_enabled;             /* Is syslog enabled? */
    char *syslog_ident;             /* Syslog ident */
    int syslog_facility;            /* Syslog facility */
    /* Replication (master) */
    int slaveseldb;                 /* Last SELECTed DB in replication output */
    long long master_repl_offset;   /* Global replication offset */
    int repl_ping_slave_period;     /* Master pings the slave every N seconds */
    char *repl_backlog;             /* Replication backlog for partial syncs */
    long long repl_backlog_size;    /* Backlog circular buffer size */
    long long repl_backlog_histlen; /* Backlog actual data length */
    long long repl_backlog_idx;     /* Backlog circular buffer current offset */
    long long repl_backlog_off;     /* Replication offset of first byte in the
                                       backlog buffer. */
    time_t repl_backlog_time_limit; /* Time without slaves after the backlog
                                       gets released. */
    time_t repl_no_slaves_since;    /* We have no slaves since that time.
                                       Only valid if server.slaves len is 0. */
    int repl_min_slaves_to_write;   /* Min number of slaves to write. */
    int repl_min_slaves_max_lag;    /* Max lag of <count> slaves to write. */
    int repl_good_slaves_count;     /* Number of slaves with lag <= max_lag. */
    /* Replication (slave) */
    char *masterauth;               /* AUTH with this password with master */
    char *masterhost;               /* Hostname of master */
    int masterport;                 /* Port of master */
    int repl_timeout;               /* Timeout after N seconds of master idle */
    redisClient *master;     /* Client that is master for this slave */
    redisClient *cached_master; /* Cached master to be reused for PSYNC. */
    int repl_syncio_timeout; /* Timeout for synchronous I/O calls */
    int repl_state;          /* Replication status if the instance is a slave */
    off_t repl_transfer_size; /* Size of RDB to read from master during sync. */
    off_t repl_transfer_read; /* Amount of RDB read from master during sync. */
    off_t repl_transfer_last_fsync_off; /* Offset when we fsync-ed last time. */
    int repl_transfer_s;     /* Slave -> Master SYNC socket */
    int repl_transfer_fd;    /* Slave -> Master SYNC temp file descriptor */
    char *repl_transfer_tmpfile; /* Slave-> master SYNC temp file name */
    time_t repl_transfer_lastio; /* Unix time of the latest read, for timeout */
    int repl_serve_stale_data; /* Serve stale data when link is down? */
    int repl_slave_ro;          /* Slave is read only? */
    time_t repl_down_since; /* Unix time at which link with master went down */
    int repl_disable_tcp_nodelay;   /* Disable TCP_NODELAY after SYNC? */
    int slave_priority;             /* Reported in INFO and used by Sentinel. */
    char repl_master_runid[REDIS_RUN_ID_SIZE+1];  /* Master run id for PSYNC. */
    long long repl_master_initial_offset;         /* Master PSYNC offset. */
    /* Replication script cache. */
    dict *repl_scriptcache_dict;        /* SHA1 all slaves are aware of. */
    list *repl_scriptcache_fifo;        /* First in, first out LRU eviction. */
    unsigned int repl_scriptcache_size; /* Max number of elements. */
    /* Limits */
    unsigned int maxclients;            /* Max number of simultaneous clients */
    unsigned long long maxmemory;   /* Max number of memory bytes to use */
    int maxmemory_policy;           /* Policy for key eviction */
    int maxmemory_samples;          /* Pricision of random sampling */
    /* Blocked clients */
    unsigned int bpop_blocked_clients; /* Number of clients blocked by lists */
    list *unblocked_clients; /* list of clients to unblock before next loop */
    list *ready_keys;        /* List of readyList structures for BLPOP & co */
    /* Sort parameters - qsort_r() is only available under BSD so we
     * have to take this state global, in order to pass it to sortCompare() */
    int sort_desc;
    int sort_alpha;
    int sort_bypattern;
    int sort_store;
    /* Zip structure config, see redis.conf for more information  */
    size_t hash_max_ziplist_entries;
    size_t hash_max_ziplist_value;
    size_t list_max_ziplist_entries;
    size_t list_max_ziplist_value;
    size_t set_max_intset_entries;
    size_t zset_max_ziplist_entries;
    size_t zset_max_ziplist_value;
    size_t hll_sparse_max_bytes;
    time_t unixtime;        /* Unix time sampled every cron cycle. */
    long long mstime;       /* Like 'unixtime' but with milliseconds resolution. */
    /* Pubsub */
    dict *pubsub_channels;  /* Map channels to list of subscribed clients */
    list *pubsub_patterns;  /* A list of pubsub_patterns */
    int notify_keyspace_events; /* Events to propagate via Pub/Sub. This is an
                                   xor of REDIS_NOTIFY... flags. */
    /* Scripting */
    lua_State *lua; /* The Lua interpreter. We use just one for all clients */
    redisClient *lua_client;   /* The "fake client" to query Redis from Lua */
    redisClient *lua_caller;   /* The client running EVAL right now, or NULL */
    dict *lua_scripts;         /* A dictionary of SHA1 -> Lua scripts */
    mstime_t lua_time_limit;  /* Script timeout in milliseconds */
    mstime_t lua_time_start;  /* Start time of script, milliseconds time */
    int lua_write_dirty;  /* True if a write command was called during the
                             execution of the current script. */
    int lua_random_dirty; /* True if a random command was called during the
                             execution of the current script. */
    int lua_timedout;     /* True if we reached the time limit for script
                             execution. */
    int lua_kill;         /* Kill the script if true. */
    /* Latency monitor */
    long long latency_monitor_threshold;
    dict *latency_events;
    /* Assert & bug reporting */
    char *assert_failed;
    char *assert_file;
    int assert_line;
    int bug_report_start; /* True if bug report header was already logged. */
    int watchdog_period;  /* Software watchdog period in ms. 0 = off */
};

typedef struct redisClient {
    uint64_t id;            /* Client incremental unique ID. */
    int fd;
    redisDb *db;
    int dictid;
    robj *name;             /* As set by CLIENT SETNAME */
    sds querybuf;
    size_t querybuf_peak;   /* Recent (100ms or more) peak of querybuf size */
    int argc;
    robj **argv;
    struct redisCommand *cmd, *lastcmd;
    int reqtype;
    int multibulklen;       /* number of multi bulk arguments left to read */
    long bulklen;           /* length of bulk argument in multi bulk request */
    list *reply;
    unsigned long reply_bytes; /* Tot bytes of objects in reply list */
    int sentlen;            /* Amount of bytes already sent in the current
                               buffer or object being sent. */
    time_t ctime;           /* Client creation time */
    time_t lastinteraction; /* time of the last interaction, used for timeout */
    time_t obuf_soft_limit_reached_time;
    int flags;              /* REDIS_SLAVE | REDIS_MONITOR | REDIS_MULTI ... */
    int authenticated;      /* when requirepass is non-NULL */
    int replstate;          /* replication state if this is a slave */
    int repldbfd;           /* replication DB file descriptor */
    off_t repldboff;        /* replication DB file offset */
    off_t repldbsize;       /* replication DB file size */
    long long reploff;      /* replication offset if this is our master */
    long long repl_ack_off; /* replication ack offset, if this is a slave */
    long long repl_ack_time;/* replication ack time, if this is a slave */
    char replrunid[REDIS_RUN_ID_SIZE+1]; /* master run id if this is a master */
    int slave_listening_port; /* As configured with: SLAVECONF listening-port */
    multiState mstate;      /* MULTI/EXEC state */
    blockingState bpop;   /* blocking state */
    list *watched_keys;     /* Keys WATCHED for MULTI/EXEC CAS */
    dict *pubsub_channels;  /* channels a client is interested in (SUBSCRIBE) */
    list *pubsub_patterns;  /* patterns a client is interested in (SUBSCRIBE) */
    sds peerid;             /* Cached peer ID. */

    /* Response buffer */
    int bufpos;
    char buf[REDIS_REPLY_CHUNK_BYTES];
} redisClient;

struct redisServer server; /* server global state */

int main(int argc, char **argv) {
   
   
    server.sentinel_mode = checkForSentinelMode(argc,argv);
    
    if (server.sentinel_mode) {
        initSentinelConfig();
        initSentinel();
    }
       
    //设置redisServer默认配置
    initServerConfig();
    
    //加载配置项
    initServer();
    
    aeSetBeforeSleepProc(server.el,beforeSleep);
    
    //事件处理主函数
    aeMain(server.el);
        
    return 0;
}

void initServerConfig(void) {
    int j;

    getRandomHexChars(server.runid,REDIS_RUN_ID_SIZE);
    
    server.configfile = NULL;
    server.hz = REDIS_DEFAULT_HZ;
    server.runid[REDIS_RUN_ID_SIZE] = '\0';
    server.arch_bits = (sizeof(long) == 8) ? 64 : 32;
    server.port = REDIS_SERVERPORT;
    server.tcp_backlog = REDIS_TCP_BACKLOG;
    server.bindaddr_count = 0;
    server.unixsocket = NULL;
    server.unixsocketperm = REDIS_DEFAULT_UNIX_SOCKET_PERM;
    server.ipfd_count = 0;
    server.sofd = -1;
    server.dbnum = REDIS_DEFAULT_DBNUM;
    server.verbosity = REDIS_DEFAULT_VERBOSITY;
    server.maxidletime = REDIS_MAXIDLETIME;
    server.tcpkeepalive = REDIS_DEFAULT_TCP_KEEPALIVE;
    server.active_expire_enabled = 1;
    server.client_max_querybuf_len = REDIS_MAX_QUERYBUF_LEN;
    server.saveparams = NULL;
    server.loading = 0;
    server.logfile = zstrdup(REDIS_DEFAULT_LOGFILE);
    server.syslog_enabled = REDIS_DEFAULT_SYSLOG_ENABLED;
    server.syslog_ident = zstrdup(REDIS_DEFAULT_SYSLOG_IDENT);
    server.syslog_facility = LOG_LOCAL0;
    server.daemonize = REDIS_DEFAULT_DAEMONIZE;
    server.aof_state = REDIS_AOF_OFF;
    server.aof_fsync = REDIS_DEFAULT_AOF_FSYNC;
    server.aof_no_fsync_on_rewrite = REDIS_DEFAULT_AOF_NO_FSYNC_ON_REWRITE;
    server.aof_rewrite_perc = REDIS_AOF_REWRITE_PERC;
    server.aof_rewrite_min_size = REDIS_AOF_REWRITE_MIN_SIZE;
    server.aof_rewrite_base_size = 0;
    server.aof_rewrite_scheduled = 0;
    server.aof_last_fsync = time(NULL);
    server.aof_rewrite_time_last = -1;
    server.aof_rewrite_time_start = -1;
    server.aof_lastbgrewrite_status = REDIS_OK;
    server.aof_delayed_fsync = 0;
    server.aof_fd = -1;
    server.aof_selected_db = -1; /* Make sure the first time will not match */
    server.aof_flush_postponed_start = 0;
    server.aof_rewrite_incremental_fsync = REDIS_DEFAULT_AOF_REWRITE_INCREMENTAL_FSYNC;
    server.aof_load_truncated = REDIS_DEFAULT_AOF_LOAD_TRUNCATED;
    server.pidfile = zstrdup(REDIS_DEFAULT_PID_FILE);
    server.rdb_filename = zstrdup(REDIS_DEFAULT_RDB_FILENAME);
    server.aof_filename = zstrdup(REDIS_DEFAULT_AOF_FILENAME);
    server.requirepass = NULL;
    server.rdb_compression = REDIS_DEFAULT_RDB_COMPRESSION;
    server.rdb_checksum = REDIS_DEFAULT_RDB_CHECKSUM;
    server.stop_writes_on_bgsave_err = REDIS_DEFAULT_STOP_WRITES_ON_BGSAVE_ERROR;
    server.activerehashing = REDIS_DEFAULT_ACTIVE_REHASHING;
    server.notify_keyspace_events = 0;
    server.maxclients = REDIS_MAX_CLIENTS;
    server.bpop_blocked_clients = 0;
    server.maxmemory = REDIS_DEFAULT_MAXMEMORY;
    server.maxmemory_policy = REDIS_DEFAULT_MAXMEMORY_POLICY;
    server.maxmemory_samples = REDIS_DEFAULT_MAXMEMORY_SAMPLES;
    server.hash_max_ziplist_entries = REDIS_HASH_MAX_ZIPLIST_ENTRIES;
    server.hash_max_ziplist_value = REDIS_HASH_MAX_ZIPLIST_VALUE;
    server.list_max_ziplist_entries = REDIS_LIST_MAX_ZIPLIST_ENTRIES;
    server.list_max_ziplist_value = REDIS_LIST_MAX_ZIPLIST_VALUE;
    server.set_max_intset_entries = REDIS_SET_MAX_INTSET_ENTRIES;
    server.zset_max_ziplist_entries = REDIS_ZSET_MAX_ZIPLIST_ENTRIES;
    server.zset_max_ziplist_value = REDIS_ZSET_MAX_ZIPLIST_VALUE;
    server.hll_sparse_max_bytes = REDIS_DEFAULT_HLL_SPARSE_MAX_BYTES;
    server.shutdown_asap = 0;
    server.repl_ping_slave_period = REDIS_REPL_PING_SLAVE_PERIOD;
    server.repl_timeout = REDIS_REPL_TIMEOUT;
    server.repl_min_slaves_to_write = REDIS_DEFAULT_MIN_SLAVES_TO_WRITE;
    server.repl_min_slaves_max_lag = REDIS_DEFAULT_MIN_SLAVES_MAX_LAG;
    server.lua_caller = NULL;
    server.lua_time_limit = REDIS_LUA_TIME_LIMIT;
    server.lua_client = NULL;
    server.lua_timedout = 0;
    server.next_client_id = 1; /* Client IDs, start from 1 .*/
    server.loading_process_events_interval_bytes = (1024*1024*2);

    updateLRUClock();
    resetServerSaveParams();

    appendServerSaveParams(60*60,1);  /* save after 1 hour and 1 change */
    appendServerSaveParams(300,100);  /* save after 5 minutes and 100 changes */
    appendServerSaveParams(60,10000); /* save after 1 minute and 10000 changes */
    
    /* Replication related */
    server.masterauth = NULL;
    server.masterhost = NULL;
    server.masterport = 6379;
    server.master = NULL;
    server.cached_master = NULL;
    server.repl_master_initial_offset = -1;
    server.repl_state = REDIS_REPL_NONE;
    server.repl_syncio_timeout = REDIS_REPL_SYNCIO_TIMEOUT;
    server.repl_serve_stale_data = REDIS_DEFAULT_SLAVE_SERVE_STALE_DATA;
    server.repl_slave_ro = REDIS_DEFAULT_SLAVE_READ_ONLY;
    server.repl_down_since = 0; /* Never connected, repl is down since EVER. */
    server.repl_disable_tcp_nodelay = REDIS_DEFAULT_REPL_DISABLE_TCP_NODELAY;
    server.slave_priority = REDIS_DEFAULT_SLAVE_PRIORITY;
    server.master_repl_offset = 0;

    /* Replication partial resync backlog */
    server.repl_backlog = NULL;
    server.repl_backlog_size = REDIS_DEFAULT_REPL_BACKLOG_SIZE;
    server.repl_backlog_histlen = 0;
    server.repl_backlog_idx = 0;
    server.repl_backlog_off = 0;
    server.repl_backlog_time_limit = REDIS_DEFAULT_REPL_BACKLOG_TIME_LIMIT;
    server.repl_no_slaves_since = time(NULL);

    /* Client output buffer limits */
    for (j = 0; j < REDIS_CLIENT_TYPE_COUNT; j++)
        server.client_obuf_limits[j] = clientBufferLimitsDefaults[j];

    /* Double constants initialization */
    R_Zero = 0.0;
    R_PosInf = 1.0/R_Zero;
    R_NegInf = -1.0/R_Zero;
    R_Nan = R_Zero/R_Zero;

    /* Command table -- we initiialize it here as it is part of the
     * initial configuration, since command names may be changed via
     * redis.conf using the rename-command directive. */
    server.commands = dictCreate(&commandTableDictType,NULL);
    server.orig_commands = dictCreate(&commandTableDictType,NULL);
    populateCommandTable();
    server.delCommand = lookupCommandByCString("del");
    server.multiCommand = lookupCommandByCString("multi");
    server.lpushCommand = lookupCommandByCString("lpush");
    server.lpopCommand = lookupCommandByCString("lpop");
    server.rpopCommand = lookupCommandByCString("rpop");

    /* Slow log */
    server.slowlog_log_slower_than = REDIS_SLOWLOG_LOG_SLOWER_THAN;
    server.slowlog_max_len = REDIS_SLOWLOG_MAX_LEN;

    /* Latency monitor */
    server.latency_monitor_threshold = REDIS_DEFAULT_LATENCY_MONITOR_THRESHOLD;

    /* Debugging */
    server.assert_failed = "<no assertion failed>";
    server.assert_file = "<no file>";
    server.assert_line = 0;
    server.bug_report_start = 0;
    server.watchdog_period = 0;
}

void initServer(void) {
   
    //设置信号处理器
    setupSignalHandlers();

    //初始化数据结构
    server.current_client = NULL;
    server.clients = listCreate();
    server.clients_to_close = listCreate();
    server.slaves = listCreate();
    server.monitors = listCreate();
    server.slaveseldb = -1; /* Force to emit the first SELECT command. */
    server.unblocked_clients = listCreate();
    server.ready_keys = listCreate();

    //创建共享对象
    createSharedObjects();
    
    adjustOpenFilesLimit();
    
    //创建事件处理模型
    server.el = aeCreateEventLoop(server.maxclients+REDIS_EVENTLOOP_FDSET_INCR);
    
    //分配数据库数组
    server.db = zmalloc(sizeof(redisDb)*server.dbnum);

    //创建监听端口
    if (server.port != 0 &&
        listenToPort(server.port,server.ipfd,&server.ipfd_count) == REDIS_ERR)
        exit(1);

  
    /* Create the Redis databases, and initialize other internal state. */
    //创建redis数据结构，初始化内部状态
    for (j = 0; j < server.dbnum; j++) {
        server.db[j].dict = dictCreate(&dbDictType,NULL);
        server.db[j].expires = dictCreate(&keyptrDictType,NULL);
        server.db[j].blocking_keys = dictCreate(&keylistDictType,NULL);
        server.db[j].ready_keys = dictCreate(&setDictType,NULL);
        server.db[j].watched_keys = dictCreate(&keylistDictType,NULL);
        server.db[j].id = j;
        server.db[j].avg_ttl = 0;
    }
    
    server.pubsub_channels = dictCreate(&keylistDictType,NULL);
    server.pubsub_patterns = listCreate();
    listSetFreeMethod(server.pubsub_patterns,freePubsubPattern);
    listSetMatchMethod(server.pubsub_patterns,listMatchPubsubPattern);
    server.cronloops = 0;
    server.rdb_child_pid = -1;
    server.aof_child_pid = -1;
    aofRewriteBufferReset();
    server.aof_buf = sdsempty();
    server.lastsave = time(NULL); /* At startup we consider the DB saved. */
    server.lastbgsave_try = 0;    /* At startup we never tried to BGSAVE. */
    server.rdb_save_time_last = -1;
    server.rdb_save_time_start = -1;
    server.dirty = 0;
    resetServerStats();
    
    /* A few stats we don't want to reset: server startup time, and peak mem. */
    server.stat_starttime = time(NULL);
    server.stat_peak_memory = 0;
    server.resident_set_size = 0;
    server.lastbgsave_status = REDIS_OK;
    server.aof_last_write_status = REDIS_OK;
    server.aof_last_write_errno = 0;
    server.repl_good_slaves_count = 0;
    
    //更新缓存时间
    updateCachedTime();

    //创建定时任务时间
    if(aeCreateTimeEvent(server.el, 1, serverCron, NULL, NULL) == AE_ERR) {
        redisPanic("Can't create the serverCron time event.");
        exit(1);
    }

    //创建文件事件处理
    for (j = 0; j < server.ipfd_count; j++) {
        aeCreateFileEvent(server.el, server.ipfd[j], AE_READABLE,acceptTcpHandler,NULL)
    }       

    //打开AOF文件
    if (server.aof_state == REDIS_AOF_ON) {
        server.aof_fd = open(server.aof_filename,O_WRONLY|O_APPEND|O_CREAT,0644);
    }

    replicationScriptCacheInit();
    scriptingInit();
    slowlogInit();
    latencyMonitorInit();
    bioInit();
}

// 事件轮询的主函数
void aeMain(aeEventLoop *eventLoop) {
    eventLoop->stop = 0;
    // 一直处理事件
    while (!eventLoop->stop) {
        // 执行处理事件之前的函数
        if (eventLoop->beforesleep != NULL)
            eventLoop->beforesleep(eventLoop);
        //处理到时的时间事件和就绪的文件事件
        aeProcessEvents(eventLoop, AE_ALL_EVENTS);
    }
}

int aeProcessEvents(aeEventLoop *eventLoop, int flags)
{
    int processed = 0, numevents;

    //没有定时事件和文件事件，则直接返回
    if (!(flags & AE_TIME_EVENTS) && !(flags & AE_FILE_EVENTS)) return 0;

    /* Note that we want call select() even if there are no
     * file events to process as long as we want to process time
     * events, in order to sleep until the next time event is ready
     * to fire. */
    if (eventLoop->maxfd != -1 ||
        
        //获取距离现在最近的定时任务
        shortest = aeSearchNearestTimer(eventLoop);

        //调用网络模型select poll epoll事件处理函数
        numevents = aeApiPoll(eventLoop, tvp);
        
        for (j = 0; j < numevents; j++) {
            aeFileEvent *fe = &eventLoop->events[eventLoop->fired[j].fd];
            int mask = eventLoop->fired[j].mask;
            int fd = eventLoop->fired[j].fd;
            int rfired = 0;
            //处理可读事件
	         if (fe->mask & mask & AE_READABLE) {
                rfired = 1;
                fe->rfileProc(eventLoop,fd,fe->clientData,mask);
            }
            //处理可写时间
            if (fe->mask & mask & AE_WRITABLE) {
                if (!rfired || fe->wfileProc != fe->rfileProc)
                    fe->wfileProc(eventLoop,fd,fe->clientData,mask);
            }
            processed++;
        }
    }
    
    //处理定时任务事件
    if (flags & AE_TIME_EVENTS)
        processed += processTimeEvents(eventLoop);

    return processed; /* return the number of processed file/time events */
}