redis版本：redis-3.2.9
在客户端输入 set name zhang，调试redis服务器，得到调用栈如下：
在dictReplace中加了断点，结果跳出来4个线程，redis还是单进程单线程吗？
上图的调用栈漏了一个栈帧：aeProcessEvents -> (networking.c) readQueryFromClient -> (networking.c) processInputBuffer
aeMain 事件循环
void aeMain(aeEventLoop *eventLoop) { eventLoop->stop = 0; while (!eventLoop->stop) { if (eventLoop->beforesleep != NULL) eventLoop->beforesleep(eventLoop); aeProcessEvents(eventLoop, AE_ALL_EVENTS); } }
aeProcessEvents 先处理文件事件（使用 epoll 选择文件事件），再处理时间事件
int aeProcessEvents(aeEventLoop *eventLoop, int flags) { int processed = 0, numevents; /* Nothing to do? return ASAP */ 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 || ((flags & AE_TIME_EVENTS) && !(flags & AE_DONT_WAIT))) { int j; aeTimeEvent *shortest = NULL; struct timeval tv, *tvp; if (flags & AE_TIME_EVENTS && !(flags & AE_DONT_WAIT)) shortest = aeSearchNearestTimer(eventLoop); if (shortest) { long now_sec, now_ms; aeGetTime(&now_sec, &now_ms); tvp = &tv; /* How many milliseconds we need to wait for the next * time event to fire? */ long long ms = (shortest->when_sec - now_sec)*1000 + shortest->when_ms - now_ms; if (ms > 0) { tvp->tv_sec = ms/1000; tvp->tv_usec = (ms % 1000)*1000; } else { tvp->tv_sec = 0; tvp->tv_usec = 0; } } else { /* If we have to check for events but need to return * ASAP because of AE_DONT_WAIT we need to set the timeout * to zero */ if (flags & AE_DONT_WAIT) { tv.tv_sec = tv.tv_usec = 0; tvp = &tv; } else { /* Otherwise we can block */ tvp = NULL; /* wait forever */ } } 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; /* note the fe->mask & mask & ... code: maybe an already processed * event removed an element that fired and we still didn't * processed, so we check if the event is still valid. */ if (fe->mask & mask & AE_READABLE) { rfired = 1; fe->rfileProc(eventLoop,fd,fe->clientData,mask); } if (fe->mask & mask & AE_WRITABLE) { if (!rfired || fe->wfileProc != fe->rfileProc) fe->wfileProc(eventLoop,fd,fe->clientData,mask); } processed++; } } /* Check time events */ if (flags & AE_TIME_EVENTS) processed += processTimeEvents(eventLoop); return processed; /* return the number of processed file/time events */ }
readQueryFromClient 客户端的命令通过网络传输到达 server，读取命令，设置到 client 的 querybuf 中
void readQueryFromClient(aeEventLoop *el, int fd, void *privdata, int mask) { client *c = (client*) privdata; int nread, readlen; size_t qblen; UNUSED(el); UNUSED(mask); readlen = PROTO_IOBUF_LEN; /* If this is a multi bulk request, and we are processing a bulk reply * that is large enough, try to maximize the probability that the query * buffer contains exactly the SDS string representing the object, even * at the risk of requiring more read(2) calls. This way the function * processMultiBulkBuffer() can avoid copying buffers to create the * Redis Object representing the argument. */ if (c->reqtype == PROTO_REQ_MULTIBULK && c->multibulklen && c->bulklen != -1 && c->bulklen >= PROTO_MBULK_BIG_ARG) { int remaining = (unsigned)(c->bulklen+2)-sdslen(c->querybuf); if (remaining < readlen) readlen = remaining; } qblen = sdslen(c->querybuf); if (c->querybuf_peak < qblen) c->querybuf_peak = qblen; c->querybuf = sdsMakeRoomFor(c->querybuf, readlen); nread = read(fd, c->querybuf+qblen, readlen); if (nread == -1) { if (errno == EAGAIN) { return; } else { serverLog(LL_VERBOSE, "Reading from client: %s",strerror(errno)); freeClient(c); return; } } else if (nread == 0) { serverLog(LL_VERBOSE, "Client closed connection"); freeClient(c); return; } sdsIncrLen(c->querybuf,nread); c->lastinteraction = server.unixtime; if (c->flags & CLIENT_MASTER) c->reploff += nread; server.stat_net_input_bytes += nread; if (sdslen(c->querybuf) > server.client_max_querybuf_len) { sds ci = catClientInfoString(sdsempty(),c), bytes = sdsempty(); bytes = sdscatrepr(bytes,c->querybuf,64); serverLog(LL_WARNING,"Closing client that reached max query buffer length: %s (qbuf initial bytes: %s)", ci, bytes); sdsfree(ci); sdsfree(bytes); freeClient(c); return; } processInputBuffer(c); }
processInputBuffer 客户端的命令全部保存在 client 的 querybuf 属性中，可能包含多条命令，例如管道，从 querybuf 中逐条解析命令，并设置 client 的 argc 和 argv 属性。
一条命令对应一个 argc 和 argv。例如 get name，此时 argv[0] 为 get，argv[1] 为 name。
void processInputBuffer(client *c) { server.current_client = c; /* Keep processing while there is something in the input buffer */ while(sdslen(c->querybuf)) { /* Return if clients are paused. */ if (!(c->flags & CLIENT_SLAVE) && clientsArePaused()) break; /* Immediately abort if the client is in the middle of something. */ if (c->flags & CLIENT_BLOCKED) break; /* CLIENT_CLOSE_AFTER_REPLY closes the connection once the reply is * written to the client. Make sure to not let the reply grow after * this flag has been set (i.e. don't process more commands). * * The same applies for clients we want to terminate ASAP. */ if (c->flags & (CLIENT_CLOSE_AFTER_REPLY|CLIENT_CLOSE_ASAP)) break; /* Determine request type when unknown. */ if (!c->reqtype) { if (c->querybuf[0] == '*') { c->reqtype = PROTO_REQ_MULTIBULK; } else { c->reqtype = PROTO_REQ_INLINE; } } if (c->reqtype == PROTO_REQ_INLINE) { if (processInlineBuffer(c) != C_OK) break; } else if (c->reqtype == PROTO_REQ_MULTIBULK) { if (processMultibulkBuffer(c) != C_OK) break; } else { serverPanic("Unknown request type"); } /* Multibulk processing could see a <= 0 length. */ if (c->argc == 0) { resetClient(c); } else { /* Only reset the client when the command was executed. */ if (processCommand(c) == C_OK) resetClient(c); /* freeMemoryIfNeeded may flush slave output buffers. This may result * into a slave, that may be the active client, to be freed. */ if (server.current_client == NULL) break; } } server.current_client = NULL; }
processCommand 根据命令名(即 argv[0])寻找对应的命令函数，给 c->cmd 赋值，以 'get name' 为例，c->cmd = {"get",getCommand,2,"rF",0,NULL,1,1,1,0,0}
int processCommand(client *c) { /* The QUIT command is handled separately. Normal command procs will * go through checking for replication and QUIT will cause trouble * when FORCE_REPLICATION is enabled and would be implemented in * a regular command proc. */ if (!strcasecmp(c->argv[0]->ptr,"quit")) { addReply(c,shared.ok); c->flags |= CLIENT_CLOSE_AFTER_REPLY; return C_ERR; } /* Now lookup the command and check ASAP about trivial error conditions * such as wrong arity, bad command name and so forth. */ c->cmd = c->lastcmd = lookupCommand(c->argv[0]->ptr); if (!c->cmd) { flagTransaction(c); addReplyErrorFormat(c,"unknown command '%s'", (char*)c->argv[0]->ptr); return C_OK; } else if ((c->cmd->arity > 0 && c->cmd->arity != c->argc) || (c->argc < -c->cmd->arity)) { flagTransaction(c); addReplyErrorFormat(c,"wrong number of arguments for '%s' command", c->cmd->name); return C_OK; } /* Check if the user is authenticated */ if (server.requirepass && !c->authenticated && c->cmd->proc != authCommand) { flagTransaction(c); addReply(c,shared.noautherr); return C_OK; } /* If cluster is enabled perform the cluster redirection here. * However we don't perform the redirection if: * 1) The sender of this command is our master. * 2) The command has no key arguments. */ if (server.cluster_enabled && !(c->flags & CLIENT_MASTER) && !(c->flags & CLIENT_LUA && server.lua_caller->flags & CLIENT_MASTER) && !(c->cmd->getkeys_proc == NULL && c->cmd->firstkey == 0 && c->cmd->proc != execCommand)) { int hashslot; int error_code; clusterNode *n = getNodeByQuery(c,c->cmd,c->argv,c->argc, &hashslot,&error_code); if (n == NULL || n != server.cluster->myself) { if (c->cmd->proc == execCommand) { discardTransaction(c); } else { flagTransaction(c); } clusterRedirectClient(c,n,hashslot,error_code); return C_OK; } } /* Handle the maxmemory directive. * * First we try to free some memory if possible (if there are volatile * keys in the dataset). If there are not the only thing we can do * is returning an error. */ if (server.maxmemory) { int retval = freeMemoryIfNeeded(); /* freeMemoryIfNeeded may flush slave output buffers. This may result * into a slave, that may be the active client, to be freed. */ if (server.current_client == NULL) return C_ERR; /* It was impossible to free enough memory, and the command the client * is trying to execute is denied during OOM conditions? Error. */ if ((c->cmd->flags & CMD_DENYOOM) && retval == C_ERR) { flagTransaction(c); addReply(c, shared.oomerr); return C_OK; } } /* Don't accept write commands if there are problems persisting on disk * and if this is a master instance. */ if (((server.stop_writes_on_bgsave_err && server.saveparamslen > 0 && server.lastbgsave_status == C_ERR) || server.aof_last_write_status == C_ERR) && server.masterhost == NULL && (c->cmd->flags & CMD_WRITE || c->cmd->proc == pingCommand)) { flagTransaction(c); if (server.aof_last_write_status == C_OK) addReply(c, shared.bgsaveerr); else addReplySds(c, sdscatprintf(sdsempty(), "-MISCONF Errors writing to the AOF file: %s ", strerror(server.aof_last_write_errno))); return C_OK; } /* Don't accept write commands if there are not enough good slaves and * user configured the min-slaves-to-write option. */ if (server.masterhost == NULL && server.repl_min_slaves_to_write && server.repl_min_slaves_max_lag && c->cmd->flags & CMD_WRITE && server.repl_good_slaves_count < server.repl_min_slaves_to_write) { flagTransaction(c); addReply(c, shared.noreplicaserr); return C_OK; } /* Don't accept write commands if this is a read only slave. But * accept write commands if this is our master. */ if (server.masterhost && server.repl_slave_ro && !(c->flags & CLIENT_MASTER) && c->cmd->flags & CMD_WRITE) { addReply(c, shared.roslaveerr); return C_OK; } /* Only allow SUBSCRIBE and UNSUBSCRIBE in the context of Pub/Sub */ if (c->flags & CLIENT_PUBSUB && c->cmd->proc != pingCommand && c->cmd->proc != subscribeCommand && c->cmd->proc != unsubscribeCommand && c->cmd->proc != psubscribeCommand && c->cmd->proc != punsubscribeCommand) { addReplyError(c,"only (P)SUBSCRIBE / (P)UNSUBSCRIBE / PING / QUIT allowed in this context"); return C_OK; } /* Only allow INFO and SLAVEOF when slave-serve-stale-data is no and * we are a slave with a broken link with master. */ if (server.masterhost && server.repl_state != REPL_STATE_CONNECTED && server.repl_serve_stale_data == 0 && !(c->cmd->flags & CMD_STALE)) { flagTransaction(c); addReply(c, shared.masterdownerr); return C_OK; } /* Loading DB? Return an error if the command has not the * CMD_LOADING flag. */ if (server.loading && !(c->cmd->flags & CMD_LOADING)) { addReply(c, shared.loadingerr); return C_OK; } /* Lua script too slow? Only allow a limited number of commands. */ if (server.lua_timedout && c->cmd->proc != authCommand && c->cmd->proc != replconfCommand && !(c->cmd->proc == shutdownCommand && c->argc == 2 && tolower(((char*)c->argv[1]->ptr)[0]) == 'n') && !(c->cmd->proc == scriptCommand && c->argc == 2 && tolower(((char*)c->argv[1]->ptr)[0]) == 'k')) { flagTransaction(c); addReply(c, shared.slowscripterr); return C_OK; } /* Exec the command */ if (c->flags & CLIENT_MULTI && c->cmd->proc != execCommand && c->cmd->proc != discardCommand && c->cmd->proc != multiCommand && c->cmd->proc != watchCommand) { queueMultiCommand(c); addReply(c,shared.queued); } else { call(c,CMD_CALL_FULL); c->woff = server.master_repl_offset; if (listLength(server.ready_keys)) handleClientsBlockedOnLists(); } return C_OK; }
redis 所有的命令存硬编码在一个数组中，数组元素包含命令名，执行函数等属性
struct redisCommand redisCommandTable[] = { {"get",getCommand,2,"rF",0,NULL,1,1,1,0,0}, {"set",setCommand,-3,"wm",0,NULL,1,1,1,0,0}, {"setnx",setnxCommand,3,"wmF",0,NULL,1,1,1,0,0}, {"setex",setexCommand,4,"wm",0,NULL,1,1,1,0,0}, {"psetex",psetexCommand,4,"wm",0,NULL,1,1,1,0,0}, {"append",appendCommand,3,"wm",0,NULL,1,1,1,0,0}, {"strlen",strlenCommand,2,"rF",0,NULL,1,1,1,0,0}, {"del",delCommand,-2,"w",0,NULL,1,-1,1,0,0}, {"exists",existsCommand,-2,"rF",0,NULL,1,-1,1,0,0}, {"setbit",setbitCommand,4,"wm",0,NULL,1,1,1,0,0}, {"getbit",getbitCommand,3,"rF",0,NULL,1,1,1,0,0}, {"bitfield",bitfieldCommand,-2,"wm",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,"wmF",0,NULL,1,1,1,0,0}, {"decr",decrCommand,2,"wmF",0,NULL,1,1,1,0,0}, {"mget",mgetCommand,-2,"r",0,NULL,1,-1,1,0,0}, {"rpush",rpushCommand,-3,"wmF",0,NULL,1,1,1,0,0}, {"lpush",lpushCommand,-3,"wmF",0,NULL,1,1,1,0,0}, {"rpushx",rpushxCommand,3,"wmF",0,NULL,1,1,1,0,0}, {"lpushx",lpushxCommand,3,"wmF",0,NULL,1,1,1,0,0}, {"linsert",linsertCommand,5,"wm",0,NULL,1,1,1,0,0}, {"rpop",rpopCommand,2,"wF",0,NULL,1,1,1,0,0}, {"lpop",lpopCommand,2,"wF",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,"rF",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,"wmF",0,NULL,1,1,1,0,0}, {"srem",sremCommand,-3,"wF",0,NULL,1,1,1,0,0}, {"smove",smoveCommand,4,"wF",0,NULL,1,2,1,0,0}, {"sismember",sismemberCommand,3,"rF",0,NULL,1,1,1,0,0}, {"scard",scardCommand,2,"rF",0,NULL,1,1,1,0,0}, {"spop",spopCommand,-2,"wRF",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}, {"sscan",sscanCommand,-3,"rR",0,NULL,1,1,1,0,0}, {"zadd",zaddCommand,-4,"wmF",0,NULL,1,1,1,0,0}, {"zincrby",zincrbyCommand,4,"wmF",0,NULL,1,1,1,0,0}, {"zrem",zremCommand,-3,"wF",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}, {"zremrangebylex",zremrangebylexCommand,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}, {"zrangebylex",zrangebylexCommand,-4,"r",0,NULL,1,1,1,0,0}, {"zrevrangebylex",zrevrangebylexCommand,-4,"r",0,NULL,1,1,1,0,0}, {"zcount",zcountCommand,4,"rF",0,NULL,1,1,1,0,0}, {"zlexcount",zlexcountCommand,4,"rF",0,NULL,1,1,1,0,0}, {"zrevrange",zrevrangeCommand,-4,"r",0,NULL,1,1,1,0,0}, {"zcard",zcardCommand,2,"rF",0,NULL,1,1,1,0,0}, {"zscore",zscoreCommand,3,"rF",0,NULL,1,1,1,0,0}, {"zrank",zrankCommand,3,"rF",0,NULL,1,1,1,0,0}, {"zrevrank",zrevrankCommand,3,"rF",0,NULL,1,1,1,0,0}, {"zscan",zscanCommand,-3,"rR",0,NULL,1,1,1,0,0}, {"hset",hsetCommand,4,"wmF",0,NULL,1,1,1,0,0}, {"hsetnx",hsetnxCommand,4,"wmF",0,NULL,1,1,1,0,0}, {"hget",hgetCommand,3,"rF",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,"wmF",0,NULL,1,1,1,0,0}, {"hincrbyfloat",hincrbyfloatCommand,4,"wmF",0,NULL,1,1,1,0,0}, {"hdel",hdelCommand,-3,"wF",0,NULL,1,1,1,0,0}, {"hlen",hlenCommand,2,"rF",0,NULL,1,1,1,0,0}, {"hstrlen",hstrlenCommand,3,"rF",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,"rF",0,NULL,1,1,1,0,0}, {"hscan",hscanCommand,-3,"rR",0,NULL,1,1,1,0,0}, {"incrby",incrbyCommand,3,"wmF",0,NULL,1,1,1,0,0}, {"decrby",decrbyCommand,3,"wmF",0,NULL,1,1,1,0,0}, {"incrbyfloat",incrbyfloatCommand,3,"wmF",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,"lF",0,NULL,0,0,0,0,0}, {"move",moveCommand,3,"wF",0,NULL,1,1,1,0,0}, {"rename",renameCommand,3,"w",0,NULL,1,2,1,0,0}, {"renamenx",renamenxCommand,3,"wF",0,NULL,1,2,1,0,0}, {"expire",expireCommand,3,"wF",0,NULL,1,1,1,0,0}, {"expireat",expireatCommand,3,"wF",0,NULL,1,1,1,0,0}, {"pexpire",pexpireCommand,3,"wF",0,NULL,1,1,1,0,0}, {"pexpireat",pexpireatCommand,3,"wF",0,NULL,1,1,1,0,0}, {"keys",keysCommand,2,"rS",0,NULL,0,0,0,0,0}, {"scan",scanCommand,-2,"rR",0,NULL,0,0,0,0,0}, {"dbsize",dbsizeCommand,1,"rF",0,NULL,0,0,0,0,0}, {"auth",authCommand,2,"sltF",0,NULL,0,0,0,0,0}, {"ping",pingCommand,-1,"tF",0,NULL,0,0,0,0,0}, {"echo",echoCommand,2,"F",0,NULL,0,0,0,0,0}, {"save",saveCommand,1,"as",0,NULL,0,0,0,0,0}, {"bgsave",bgsaveCommand,-1,"a",0,NULL,0,0,0,0,0}, {"bgrewriteaof",bgrewriteaofCommand,1,"a",0,NULL,0,0,0,0,0}, {"shutdown",shutdownCommand,-1,"alt",0,NULL,0,0,0,0,0}, {"lastsave",lastsaveCommand,1,"RF",0,NULL,0,0,0,0,0}, {"type",typeCommand,2,"rF",0,NULL,1,1,1,0,0}, {"multi",multiCommand,1,"sF",0,NULL,0,0,0,0,0}, {"exec",execCommand,1,"sM",0,NULL,0,0,0,0,0}, {"discard",discardCommand,1,"sF",0,NULL,0,0,0,0,0}, {"sync",syncCommand,1,"ars",0,NULL,0,0,0,0,0}, {"psync",syncCommand,3,"ars",0,NULL,0,0,0,0,0}, {"replconf",replconfCommand,-1,"aslt",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,sortGetKeys,1,1,1,0,0}, {"info",infoCommand,-1,"lt",0,NULL,0,0,0,0,0}, {"monitor",monitorCommand,1,"as",0,NULL,0,0,0,0,0}, {"ttl",ttlCommand,2,"rF",0,NULL,1,1,1,0,0}, {"touch",touchCommand,-2,"rF",0,NULL,1,1,1,0,0}, {"pttl",pttlCommand,2,"rF",0,NULL,1,1,1,0,0}, {"persist",persistCommand,2,"wF",0,NULL,1,1,1,0,0}, {"slaveof",slaveofCommand,3,"ast",0,NULL,0,0,0,0,0}, {"role",roleCommand,1,"lst",0,NULL,0,0,0,0,0}, {"debug",debugCommand,-1,"as",0,NULL,0,0,0,0,0}, {"config",configCommand,-2,"lat",0,NULL,0,0,0,0,0}, {"subscribe",subscribeCommand,-2,"pslt",0,NULL,0,0,0,0,0}, {"unsubscribe",unsubscribeCommand,-1,"pslt",0,NULL,0,0,0,0,0}, {"psubscribe",psubscribeCommand,-2,"pslt",0,NULL,0,0,0,0,0}, {"punsubscribe",punsubscribeCommand,-1,"pslt",0,NULL,0,0,0,0,0}, {"publish",publishCommand,3,"pltF",0,NULL,0,0,0,0,0}, {"pubsub",pubsubCommand,-2,"pltR",0,NULL,0,0,0,0,0}, {"watch",watchCommand,-2,"sF",0,NULL,1,-1,1,0,0}, {"unwatch",unwatchCommand,1,"sF",0,NULL,0,0,0,0,0}, {"cluster",clusterCommand,-2,"a",0,NULL,0,0,0,0,0}, {"restore",restoreCommand,-4,"wm",0,NULL,1,1,1,0,0}, {"restore-asking",restoreCommand,-4,"wmk",0,NULL,1,1,1,0,0}, {"migrate",migrateCommand,-6,"w",0,migrateGetKeys,0,0,0,0,0}, {"asking",askingCommand,1,"F",0,NULL,0,0,0,0,0}, {"readonly",readonlyCommand,1,"F",0,NULL,0,0,0,0,0}, {"readwrite",readwriteCommand,1,"F",0,NULL,0,0,0,0,0}, {"dump",dumpCommand,2,"r",0,NULL,1,1,1,0,0}, {"object",objectCommand,3,"r",0,NULL,2,2,2,0,0}, {"client",clientCommand,-2,"as",0,NULL,0,0,0,0,0}, {"eval",evalCommand,-3,"s",0,evalGetKeys,0,0,0,0,0}, {"evalsha",evalShaCommand,-3,"s",0,evalGetKeys,0,0,0,0,0}, {"slowlog",slowlogCommand,-2,"a",0,NULL,0,0,0,0,0}, {"script",scriptCommand,-2,"s",0,NULL,0,0,0,0,0}, {"time",timeCommand,1,"RF",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}, {"bitpos",bitposCommand,-3,"r",0,NULL,1,1,1,0,0}, {"wait",waitCommand,3,"s",0,NULL,0,0,0,0,0}, {"command",commandCommand,0,"lt",0,NULL,0,0,0,0,0}, {"geoadd",geoaddCommand,-5,"wm",0,NULL,1,1,1,0,0}, {"georadius",georadiusCommand,-6,"w",0,NULL,1,1,1,0,0}, {"georadiusbymember",georadiusByMemberCommand,-5,"w",0,NULL,1,1,1,0,0}, {"geohash",geohashCommand,-2,"r",0,NULL,1,1,1,0,0}, {"geopos",geoposCommand,-2,"r",0,NULL,1,1,1,0,0}, {"geodist",geodistCommand,-4,"r",0,NULL,1,1,1,0,0}, {"pfselftest",pfselftestCommand,1,"a",0,NULL,0,0,0,0,0}, {"pfadd",pfaddCommand,-2,"wmF",0,NULL,1,1,1,0,0}, {"pfcount",pfcountCommand,-2,"r",0,NULL,1,-1,1,0,0}, {"pfmerge",pfmergeCommand,-2,"wm",0,NULL,1,-1,1,0,0}, {"pfdebug",pfdebugCommand,-3,"w",0,NULL,0,0,0,0,0}, {"post",securityWarningCommand,-1,"lt",0,NULL,0,0,0,0,0}, {"host:",securityWarningCommand,-1,"lt",0,NULL,0,0,0,0,0}, {"latency",latencyCommand,-2,"aslt",0,NULL,0,0,0,0,0} };
而这些命令会存放在一个字典中 dict *commands
void populateCommandTable(void) { int j; int numcommands = sizeof(redisCommandTable)/sizeof(struct redisCommand); for (j = 0; j < numcommands; j++) { struct redisCommand *c = redisCommandTable+j; char *f = c->sflags; int retval1, retval2; while(*f != ' ') { switch(*f) { case 'w': c->flags |= CMD_WRITE; break; case 'r': c->flags |= CMD_READONLY; break; case 'm': c->flags |= CMD_DENYOOM; break; case 'a': c->flags |= CMD_ADMIN; break; case 'p': c->flags |= CMD_PUBSUB; break; case 's': c->flags |= CMD_NOSCRIPT; break; case 'R': c->flags |= CMD_RANDOM; break; case 'S': c->flags |= CMD_SORT_FOR_SCRIPT; break; case 'l': c->flags |= CMD_LOADING; break; case 't': c->flags |= CMD_STALE; break; case 'M': c->flags |= CMD_SKIP_MONITOR; break; case 'k': c->flags |= CMD_ASKING; break; case 'F': c->flags |= CMD_FAST; break; default: serverPanic("Unsupported command flag"); break; } f++; } retval1 = dictAdd(server.commands, sdsnew(c->name), c); /* Populate an additional dictionary that will be unaffected * by rename-command statements in redis.conf. */ retval2 = dictAdd(server.orig_commands, sdsnew(c->name), c); serverAssert(retval1 == DICT_OK && retval2 == DICT_OK); } }
call 执行具体命令，并且传播命令，等等。
void call(client *c, int flags) { long long dirty, start, duration; int client_old_flags = c->flags; /* Sent the command to clients in MONITOR mode, only if the commands are * not generated from reading an AOF. */ if (listLength(server.monitors) && !server.loading && !(c->cmd->flags & (CMD_SKIP_MONITOR|CMD_ADMIN))) { replicationFeedMonitors(c,server.monitors,c->db->id,c->argv,c->argc); } /* Initialization: clear the flags that must be set by the command on * demand, and initialize the array for additional commands propagation. */ c->flags &= ~(CLIENT_FORCE_AOF|CLIENT_FORCE_REPL|CLIENT_PREVENT_PROP); redisOpArrayInit(&server.also_propagate); /* Call the command. */ dirty = server.dirty; start = ustime(); c->cmd->proc(c); duration = ustime()-start; dirty = server.dirty-dirty; if (dirty < 0) dirty = 0; /* When EVAL is called loading the AOF we don't want commands called * from Lua to go into the slowlog or to populate statistics. */ if (server.loading && c->flags & CLIENT_LUA) flags &= ~(CMD_CALL_SLOWLOG | CMD_CALL_STATS); /* If the caller is Lua, we want to force the EVAL caller to propagate * the script if the command flag or client flag are forcing the * propagation. */ if (c->flags & CLIENT_LUA && server.lua_caller) { if (c->flags & CLIENT_FORCE_REPL) server.lua_caller->flags |= CLIENT_FORCE_REPL; if (c->flags & CLIENT_FORCE_AOF) server.lua_caller->flags |= CLIENT_FORCE_AOF; } /* Log the command into the Slow log if needed, and populate the * per-command statistics that we show in INFO commandstats. */ if (flags & CMD_CALL_SLOWLOG && c->cmd->proc != execCommand) { char *latency_event = (c->cmd->flags & CMD_FAST) ? "fast-command" : "command"; latencyAddSampleIfNeeded(latency_event,duration/1000); slowlogPushEntryIfNeeded(c->argv,c->argc,duration); } if (flags & CMD_CALL_STATS) { c->lastcmd->microseconds += duration; c->lastcmd->calls++; } /* Propagate the command into the AOF and replication link */ if (flags & CMD_CALL_PROPAGATE && (c->flags & CLIENT_PREVENT_PROP) != CLIENT_PREVENT_PROP) { int propagate_flags = PROPAGATE_NONE; /* Check if the command operated changes in the data set. If so * set for replication / AOF propagation. */ if (dirty) propagate_flags |= (PROPAGATE_AOF|PROPAGATE_REPL); /* If the client forced AOF / replication of the command, set * the flags regardless of the command effects on the data set. */ if (c->flags & CLIENT_FORCE_REPL) propagate_flags |= PROPAGATE_REPL; if (c->flags & CLIENT_FORCE_AOF) propagate_flags |= PROPAGATE_AOF; /* However prevent AOF / replication propagation if the command * implementatino called preventCommandPropagation() or similar, * or if we don't have the call() flags to do so. */ if (c->flags & CLIENT_PREVENT_REPL_PROP || !(flags & CMD_CALL_PROPAGATE_REPL)) propagate_flags &= ~PROPAGATE_REPL; if (c->flags & CLIENT_PREVENT_AOF_PROP || !(flags & CMD_CALL_PROPAGATE_AOF)) propagate_flags &= ~PROPAGATE_AOF; /* Call propagate() only if at least one of AOF / replication * propagation is needed. */ if (propagate_flags != PROPAGATE_NONE) propagate(c->cmd,c->db->id,c->argv,c->argc,propagate_flags); } /* Restore the old replication flags, since call() can be executed * recursively. */ c->flags &= ~(CLIENT_FORCE_AOF|CLIENT_FORCE_REPL|CLIENT_PREVENT_PROP); c->flags |= client_old_flags & (CLIENT_FORCE_AOF|CLIENT_FORCE_REPL|CLIENT_PREVENT_PROP); /* Handle the alsoPropagate() API to handle commands that want to propagate * multiple separated commands. Note that alsoPropagate() is not affected * by CLIENT_PREVENT_PROP flag. */ if (server.also_propagate.numops) { int j; redisOp *rop; if (flags & CMD_CALL_PROPAGATE) { for (j = 0; j < server.also_propagate.numops; j++) { rop = &server.also_propagate.ops[j]; int target = rop->target; /* Whatever the command wish is, we honor the call() flags. */ if (!(flags&CMD_CALL_PROPAGATE_AOF)) target &= ~PROPAGATE_AOF; if (!(flags&CMD_CALL_PROPAGATE_REPL)) target &= ~PROPAGATE_REPL; if (target) propagate(rop->cmd,rop->dbid,rop->argv,rop->argc,target); } } redisOpArrayFree(&server.also_propagate); } server.stat_numcommands++; }
c->cmd->proc(c); 是调用具体的命令。以 'get name' 为例，c->cmd->proc = getCommand
int getGenericCommand(client *c) { robj *o; if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL) return C_OK; if (o->type != OBJ_STRING) { addReply(c,shared.wrongtypeerr); return C_ERR; } else { addReplyBulk(c,o); return C_OK; } } void getCommand(client *c) { getGenericCommand(c); }
执行命令，把响应添加到缓冲区
client 有 2 个输出缓冲区可用，一个是 char buf[PROTO_REPLY_CHUNK_BYTES]，一个是 list *reply，首先使用 buf，当 buf 不足时，使用 reply
发送响应： (t_string.c) setGenericCommand -> (networking.c) addReply
void addReply(client *c, robj *obj) { if (prepareClientToWrite(c) != C_OK) return; /* This is an important place where we can avoid copy-on-write * when there is a saving child running, avoiding touching the * refcount field of the object if it's not needed. * * If the encoding is RAW and there is room in the static buffer * we'll be able to send the object to the client without * messing with its page. */ if (sdsEncodedObject(obj)) { if (_addReplyToBuffer(c,obj->ptr,sdslen(obj->ptr)) != C_OK) _addReplyObjectToList(c,obj); } else if (obj->encoding == OBJ_ENCODING_INT) { /* Optimization: if there is room in the static buffer for 32 bytes * (more than the max chars a 64 bit integer can take as string) we * avoid decoding the object and go for the lower level approach. */ if (listLength(c->reply) == 0 && (sizeof(c->buf) - c->bufpos) >= 32) { char buf[32]; int len; len = ll2string(buf,sizeof(buf),(long)obj->ptr); if (_addReplyToBuffer(c,buf,len) == C_OK) return; /* else... continue with the normal code path, but should never * happen actually since we verified there is room. */ } obj = getDecodedObject(obj); if (_addReplyToBuffer(c,obj->ptr,sdslen(obj->ptr)) != C_OK) _addReplyObjectToList(c,obj); decrRefCount(obj); } else { serverPanic("Wrong obj->encoding in addReply()"); } } int _addReplyToBuffer(client *c, const char *s, size_t len) { size_t available = sizeof(c->buf)-c->bufpos; if (c->flags & CLIENT_CLOSE_AFTER_REPLY) return C_OK; /* If there already are entries in the reply list, we cannot * add anything more to the static buffer. */ if (listLength(c->reply) > 0) return C_ERR; /* Check that the buffer has enough space available for this string. */ if (len > available) return C_ERR; memcpy(c->buf+c->bufpos,s,len); c->bufpos+=len; return C_OK; }
那么客户端的响应是什么时候从缓冲区发送出去的呢？
void aeMain(aeEventLoop *eventLoop) { eventLoop->stop = 0; while (!eventLoop->stop) { if (eventLoop->beforesleep != NULL) eventLoop->beforesleep(eventLoop); aeProcessEvents(eventLoop, AE_ALL_EVENTS); } }