Redis Startup Process Analysis

The components involved in Redis are based on the C language. Each C file corresponds to a module and can be considered as a component. Based on the analysis of its source code, we can conclude that the following components and modules and methods are involved when the Redis service is started.

Startup sequence diagram

In the main function of redis. c, we mainly do three things:

1) Loading configuration includes loading from the command line or passing in the configuration file;

2) Start listening for unix and tcp, and save the client list in the clients of redisserver;

3) Start the AE event.

After the startup is complete, AE will query each client for input at a specific time. If any input is read from the client and the command is parsed.

The Command Parsing is mainly based on redisserver's redisCommandTable (redis. c). The structure shows the list of all REDIS commands and corresponding processing functions.

struct redisCommand redisCommandTable[] = {    {"get",getCommand,2,"r",0,NULL,1,1,1,0,0},    {"set",setCommand,-3,"wm",0,noPreloadGetKeys,1,1,1,0,0},    {"setnx",setnxCommand,3,"wm",0,noPreloadGetKeys,1,1,1,0,0},    {"setex",setexCommand,4,"wm",0,noPreloadGetKeys,1,1,1,0,0},    {"psetex",psetexCommand,4,"wm",0,noPreloadGetKeys,1,1,1,0,0},    {"append",appendCommand,3,"wm",0,NULL,1,1,1,0,0},    {"strlen",strlenCommand,2,"r",0,NULL,1,1,1,0,0},    {"del",delCommand,-2,"w",0,noPreloadGetKeys,1,-1,1,0,0},    {"exists",existsCommand,2,"r",0,NULL,1,1,1,0,0},    {"setbit",setbitCommand,4,"wm",0,NULL,1,1,1,0,0},    {"getbit",getbitCommand,3,"r",0,NULL,1,1,1,0,0},    {"setrange",setrangeCommand,4,"wm",0,NULL,1,1,1,0,0},    {"getrange",getrangeCommand,4,"r",0,NULL,1,1,1,0,0},    {"substr",getrangeCommand,4,"r",0,NULL,1,1,1,0,0},    {"incr",incrCommand,2,"wm",0,NULL,1,1,1,0,0},    {"decr",decrCommand,2,"wm",0,NULL,1,1,1,0,0},    {"mget",mgetCommand,-2,"r",0,NULL,1,-1,1,0,0},    {"rpush",rpushCommand,-3,"wm",0,NULL,1,1,1,0,0},    {"lpush",lpushCommand,-3,"wm",0,NULL,1,1,1,0,0},    {"rpushx",rpushxCommand,3,"wm",0,NULL,1,1,1,0,0},    {"lpushx",lpushxCommand,3,"wm",0,NULL,1,1,1,0,0},    {"linsert",linsertCommand,5,"wm",0,NULL,1,1,1,0,0},    {"rpop",rpopCommand,2,"w",0,NULL,1,1,1,0,0},    {"lpop",lpopCommand,2,"w",0,NULL,1,1,1,0,0},    {"brpop",brpopCommand,-3,"ws",0,NULL,1,1,1,0,0},    {"brpoplpush",brpoplpushCommand,4,"wms",0,NULL,1,2,1,0,0},    {"blpop",blpopCommand,-3,"ws",0,NULL,1,-2,1,0,0},    {"llen",llenCommand,2,"r",0,NULL,1,1,1,0,0},    {"lindex",lindexCommand,3,"r",0,NULL,1,1,1,0,0},    {"lset",lsetCommand,4,"wm",0,NULL,1,1,1,0,0},    {"lrange",lrangeCommand,4,"r",0,NULL,1,1,1,0,0},    {"ltrim",ltrimCommand,4,"w",0,NULL,1,1,1,0,0},    {"lrem",lremCommand,4,"w",0,NULL,1,1,1,0,0},    {"rpoplpush",rpoplpushCommand,3,"wm",0,NULL,1,2,1,0,0},    {"sadd",saddCommand,-3,"wm",0,NULL,1,1,1,0,0},    {"srem",sremCommand,-3,"w",0,NULL,1,1,1,0,0},    {"smove",smoveCommand,4,"w",0,NULL,1,2,1,0,0},    {"sismember",sismemberCommand,3,"r",0,NULL,1,1,1,0,0},    {"scard",scardCommand,2,"r",0,NULL,1,1,1,0,0},    {"spop",spopCommand,2,"wRs",0,NULL,1,1,1,0,0},    {"srandmember",srandmemberCommand,-2,"rR",0,NULL,1,1,1,0,0},    {"sinter",sinterCommand,-2,"rS",0,NULL,1,-1,1,0,0},    {"sinterstore",sinterstoreCommand,-3,"wm",0,NULL,1,-1,1,0,0},    {"sunion",sunionCommand,-2,"rS",0,NULL,1,-1,1,0,0},    {"sunionstore",sunionstoreCommand,-3,"wm",0,NULL,1,-1,1,0,0},    {"sdiff",sdiffCommand,-2,"rS",0,NULL,1,-1,1,0,0},    {"sdiffstore",sdiffstoreCommand,-3,"wm",0,NULL,1,-1,1,0,0},    {"smembers",sinterCommand,2,"rS",0,NULL,1,1,1,0,0},    {"zadd",zaddCommand,-4,"wm",0,NULL,1,1,1,0,0},    {"zincrby",zincrbyCommand,4,"wm",0,NULL,1,1,1,0,0},    {"zrem",zremCommand,-3,"w",0,NULL,1,1,1,0,0},    {"zremrangebyscore",zremrangebyscoreCommand,4,"w",0,NULL,1,1,1,0,0},    {"zremrangebyrank",zremrangebyrankCommand,4,"w",0,NULL,1,1,1,0,0},    {"zunionstore",zunionstoreCommand,-4,"wm",0,zunionInterGetKeys,0,0,0,0,0},    {"zinterstore",zinterstoreCommand,-4,"wm",0,zunionInterGetKeys,0,0,0,0,0},    {"zrange",zrangeCommand,-4,"r",0,NULL,1,1,1,0,0},    {"zrangebyscore",zrangebyscoreCommand,-4,"r",0,NULL,1,1,1,0,0},    {"zrevrangebyscore",zrevrangebyscoreCommand,-4,"r",0,NULL,1,1,1,0,0},    {"zcount",zcountCommand,4,"r",0,NULL,1,1,1,0,0},    {"zrevrange",zrevrangeCommand,-4,"r",0,NULL,1,1,1,0,0},    {"zcard",zcardCommand,2,"r",0,NULL,1,1,1,0,0},    {"zscore",zscoreCommand,3,"r",0,NULL,1,1,1,0,0},    {"zrank",zrankCommand,3,"r",0,NULL,1,1,1,0,0},    {"zrevrank",zrevrankCommand,3,"r",0,NULL,1,1,1,0,0},    {"hset",hsetCommand,4,"wm",0,NULL,1,1,1,0,0},    {"hsetnx",hsetnxCommand,4,"wm",0,NULL,1,1,1,0,0},    {"hget",hgetCommand,3,"r",0,NULL,1,1,1,0,0},    {"hmset",hmsetCommand,-4,"wm",0,NULL,1,1,1,0,0},    {"hmget",hmgetCommand,-3,"r",0,NULL,1,1,1,0,0},    {"hincrby",hincrbyCommand,4,"wm",0,NULL,1,1,1,0,0},    {"hincrbyfloat",hincrbyfloatCommand,4,"wm",0,NULL,1,1,1,0,0},    {"hdel",hdelCommand,-3,"w",0,NULL,1,1,1,0,0},    {"hlen",hlenCommand,2,"r",0,NULL,1,1,1,0,0},    {"hkeys",hkeysCommand,2,"rS",0,NULL,1,1,1,0,0},    {"hvals",hvalsCommand,2,"rS",0,NULL,1,1,1,0,0},    {"hgetall",hgetallCommand,2,"r",0,NULL,1,1,1,0,0},    {"hexists",hexistsCommand,3,"r",0,NULL,1,1,1,0,0},    {"incrby",incrbyCommand,3,"wm",0,NULL,1,1,1,0,0},    {"decrby",decrbyCommand,3,"wm",0,NULL,1,1,1,0,0},    {"incrbyfloat",incrbyfloatCommand,3,"wm",0,NULL,1,1,1,0,0},    {"getset",getsetCommand,3,"wm",0,NULL,1,1,1,0,0},    {"mset",msetCommand,-3,"wm",0,NULL,1,-1,2,0,0},    {"msetnx",msetnxCommand,-3,"wm",0,NULL,1,-1,2,0,0},    {"randomkey",randomkeyCommand,1,"rR",0,NULL,0,0,0,0,0},    {"select",selectCommand,2,"rl",0,NULL,0,0,0,0,0},    {"move",moveCommand,3,"w",0,NULL,1,1,1,0,0},    {"rename",renameCommand,3,"w",0,renameGetKeys,1,2,1,0,0},    {"renamenx",renamenxCommand,3,"w",0,renameGetKeys,1,2,1,0,0},    {"expire",expireCommand,3,"w",0,NULL,1,1,1,0,0},    {"expireat",expireatCommand,3,"w",0,NULL,1,1,1,0,0},    {"pexpire",pexpireCommand,3,"w",0,NULL,1,1,1,0,0},    {"pexpireat",pexpireatCommand,3,"w",0,NULL,1,1,1,0,0},    {"keys",keysCommand,2,"rS",0,NULL,0,0,0,0,0},    {"dbsize",dbsizeCommand,1,"r",0,NULL,0,0,0,0,0},    {"auth",authCommand,2,"rsl",0,NULL,0,0,0,0,0},    {"ping",pingCommand,1,"r",0,NULL,0,0,0,0,0},    {"echo",echoCommand,2,"r",0,NULL,0,0,0,0,0},    {"save",saveCommand,1,"ars",0,NULL,0,0,0,0,0},    {"bgsave",bgsaveCommand,1,"ar",0,NULL,0,0,0,0,0},    {"bgrewriteaof",bgrewriteaofCommand,1,"ar",0,NULL,0,0,0,0,0},    {"shutdown",shutdownCommand,-1,"ar",0,NULL,0,0,0,0,0},    {"lastsave",lastsaveCommand,1,"rR",0,NULL,0,0,0,0,0},    {"type",typeCommand,2,"r",0,NULL,1,1,1,0,0},    {"multi",multiCommand,1,"rs",0,NULL,0,0,0,0,0},    {"exec",execCommand,1,"sM",0,NULL,0,0,0,0,0},    {"discard",discardCommand,1,"rs",0,NULL,0,0,0,0,0},    {"sync",syncCommand,1,"ars",0,NULL,0,0,0,0,0},    {"replconf",replconfCommand,-1,"ars",0,NULL,0,0,0,0,0},    {"flushdb",flushdbCommand,1,"w",0,NULL,0,0,0,0,0},    {"flushall",flushallCommand,1,"w",0,NULL,0,0,0,0,0},    {"sort",sortCommand,-2,"wm",0,NULL,1,1,1,0,0},    {"info",infoCommand,-1,"rlt",0,NULL,0,0,0,0,0},    {"monitor",monitorCommand,1,"ars",0,NULL,0,0,0,0,0},    {"ttl",ttlCommand,2,"r",0,NULL,1,1,1,0,0},    {"pttl",pttlCommand,2,"r",0,NULL,1,1,1,0,0},    {"persist",persistCommand,2,"w",0,NULL,1,1,1,0,0},    {"slaveof",slaveofCommand,3,"ast",0,NULL,0,0,0,0,0},    {"debug",debugCommand,-2,"as",0,NULL,0,0,0,0,0},    {"config",configCommand,-2,"ar",0,NULL,0,0,0,0,0},    {"subscribe",subscribeCommand,-2,"rpslt",0,NULL,0,0,0,0,0},    {"unsubscribe",unsubscribeCommand,-1,"rpslt",0,NULL,0,0,0,0,0},    {"psubscribe",psubscribeCommand,-2,"rpslt",0,NULL,0,0,0,0,0},    {"punsubscribe",punsubscribeCommand,-1,"rpslt",0,NULL,0,0,0,0,0},    {"publish",publishCommand,3,"pfltr",0,NULL,0,0,0,0,0},    {"watch",watchCommand,-2,"rs",0,noPreloadGetKeys,1,-1,1,0,0},    {"unwatch",unwatchCommand,1,"rs",0,NULL,0,0,0,0,0},    {"restore",restoreCommand,4,"awm",0,NULL,1,1,1,0,0},    {"migrate",migrateCommand,6,"aw",0,NULL,0,0,0,0,0},    {"dump",dumpCommand,2,"ar",0,NULL,1,1,1,0,0},    {"object",objectCommand,-2,"r",0,NULL,2,2,2,0,0},    {"client",clientCommand,-2,"ar",0,NULL,0,0,0,0,0},    {"eval",evalCommand,-3,"s",0,zunionInterGetKeys,0,0,0,0,0},    {"evalsha",evalShaCommand,-3,"s",0,zunionInterGetKeys,0,0,0,0,0},    {"slowlog",slowlogCommand,-2,"r",0,NULL,0,0,0,0,0},    {"script",scriptCommand,-2,"ras",0,NULL,0,0,0,0,0},    {"time",timeCommand,1,"rR",0,NULL,0,0,0,0,0},    {"bitop",bitopCommand,-4,"wm",0,NULL,2,-1,1,0,0},    {"bitcount",bitcountCommand,-2,"r",0,NULL,1,1,1,0,0}};