redis键值数据库源码分析

/* * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com> * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of Redis nor the names of its contributors may be used * to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "redis.h" #include "slowlog.h" #include "bio.h" #include <time.h> #include <signal.h> #include <sys/wait.h> #include <errno.h> #include <assert.h> #include <ctype.h> #include <stdarg.h> #include <arpa/inet.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/time.h> #include <sys/resource.h> #include <sys/uio.h> #include <limits.h> #include <float.h> #include <math.h> #include <sys/resource.h> #include <sys/utsname.h> #include <locale.h> /* Our shared "common" objects */ /* 共享的对象 */ struct sharedObjectsStruct shared; /* Global vars that are actually used as constants. The following double * values are used for double on-disk serialization, and are initialized * at runtime to avoid strange compiler optimizations. */ /* 全局的double类型常量 */ double R_Zero, R_PosInf, R_NegInf, R_Nan; /*================================= Globals ================================= */ /* Global vars */ /* 全局的RedisServer */ struct redisServer server; /* server global state */ /* Our command table. * * Every entry is composed of the following fields: * * name: a string representing the command name. * function: pointer to the C function implementing the command. * arity: number of arguments, it is possible to use -N to say >= N * sflags: command flags as string. See below for a table of flags. * flags: flags as bitmask. Computed by Redis using the 'sflags' field. * get_keys_proc: an optional function to get key arguments from a command. * This is only used when the following three fields are not * enough to specify what arguments are keys. * first_key_index: first argument that is a key * last_key_index: last argument that is a key * key_step: step to get all the keys from first to last argument. For instance * in MSET the step is two since arguments are key,val,key,val,... * microseconds: microseconds of total execution time for this command. * calls: total number of calls of this command. * * The flags, microseconds and calls fields are computed by Redis and should * always be set to zero. * * Command flags are expressed using strings where every character represents * a flag. Later the populateCommandTable() function will take care of * populating the real 'flags' field using this characters. * * This is the meaning of the flags: * * w: write command (may modify the key space). * r: read command (will never modify the key space). * m: may increase memory usage once called. Don't allow if out of memory. * a: admin command, like SAVE or SHUTDOWN. * p: Pub/Sub related command. * f: force replication of this command, regardless of server.dirty. * s: command not allowed in scripts. * R: random command. Command is not deterministic, that is, the same command * with the same arguments, with the same key space, may have different * results. For instance SPOP and RANDOMKEY are two random commands. * S: Sort command output array if called from script, so that the output * is deterministic. * l: Allow command while loading the database. * t: Allow command while a slave has stale data but is not allowed to * server this data. Normally no command is accepted in this condition * but just a few. * M: Do not automatically propagate the command on MONITOR. * F: Fast command: O(1) or O(log(N)) command that should never delay * its execution as long as the kernel scheduler is giving us time. * Note that commands that may trigger a DEL as a side effect (like SET) * are not fast commands. */ /* redis命令表格对应关系 */ 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}, {"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,"wRsF",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,