ZADD

ZADD key [NX|XX] [CH] [INCR]score member [score member ...]

将元素及对应分值添加到一个有序集合中

NX:不更新已经存在的key,只增加新元素

XX:只更新已经存在的key,不增加新元素

CH:abbr:changed.不指定时只返回新增的元素个数,指定时返回新增的和更新的元素个数之和

INCR:参考zincrby

//通过第二个参数区分是zadd还是zincrbyvoid zaddCommand(client *c) {    zaddGenericCommand(c,ZADD_NONE);}

/* This generic command implements both ZADD and ZINCRBY. *///zadd和zincrby两个命令都是调用这个函数void zaddGenericCommand(client *c, int flags) {    static char *nanerr = "resulting score is not a number (NaN)";    robj *key = c->argv[1];    robj *zobj;    sds ele;    double score = 0, *scores = NULL;    int j, elements;    int scoreidx = 0;    /* The following vars are used in order to track what the command actually     * did during the execution, to reply to the client and to trigger the     * notification of keyspace change. */    int added = 0;      /* Number of new elements added. */    int updated = 0;    /* Number of elements with updated score. */    int processed = 0;  /* Number of elements processed, may remain zero with                           options like XX. */    /* Parse options. At the end 'scoreidx' is set to the argument position     * of the score of the first score-element pair. */    scoreidx = 2;//从第二个参数开始处理.先处理nx,xx,ch,incr参数    while(scoreidx < c->argc) {        char *opt = c->argv[scoreidx]->ptr;        if (!strcasecmp(opt,"nx")) flags |= ZADD_NX;        else if (!strcasecmp(opt,"xx")) flags |= ZADD_XX;        else if (!strcasecmp(opt,"ch")) flags |= ZADD_CH;        else if (!strcasecmp(opt,"incr")) flags |= ZADD_INCR;        else break;        scoreidx++;    }    /* Turn options into simple to check vars. */    //从flag中取出相应的标志赋给独立的变量    int incr = (flags & ZADD_INCR) != 0;    int nx = (flags & ZADD_NX) != 0;    int xx = (flags & ZADD_XX) != 0;    int ch = (flags & ZADD_CH) != 0;    /* After the options, we expect to have an even number of args, since     * we expect any number of score-element pairs. */    //member和score是一一对应的,所以肯定是2的倍数.所以如果不是2的倍数或者根本    //没有member和score,直接返回命令语法错误    elements = c->argc-scoreidx;    if (elements % 2 || !elements) {        addReply(c,shared.syntaxerr);        return;    }    //elements赋值为有多少对
    
         elements /= 2; /* Now this holds the number of score-element pairs. */    /* Check for incompatible options. */    //nx和xxflag互斥,二者不能同时出现    if (nx && xx) {        addReplyError(c,            "XX and NX options at the same time are not compatible");        return;    }    //若有incr标志,则只能有一对
     
          //为什么不能是多对?    if (incr && elements > 1) {        addReplyError(c,            "INCR option supports a single increment-element pair");        return;    }    /* Start parsing all the scores, we need to emit any syntax error     * before executing additions to the sorted set, as the command should     * either execute fully or nothing at all. */    //依次检查每一个分数值    scores = zmalloc(sizeof(double)*elements);    for (j = 0; j < elements; j++) {        //该函数中会检查score是否是合法的double类型的值        if (getDoubleFromObjectOrReply(c,c->argv[scoreidx+j*2],&scores[j],NULL)            != C_OK) goto cleanup;    }    /* Lookup the key and create the sorted set if does not exist. */    //根据key查找对应的有序集合的value    zobj = lookupKeyWrite(c->db,key);    //key不存在    if (zobj == NULL) {        //如果设置了xx这个flag,直接返回错误        if (xx) goto reply_to_client; /* No key + XX option: nothing to do. */        //根据redis的配置,如果有序集合设置了不使用ziplist存储或者说第一个插入元素的长度大于        //设置的最大ziplist的元素长度值,则使用跳跃表存储否则使用ziplist        if (server.zset_max_ziplist_entries == 0 ||            server.zset_max_ziplist_value < sdslen(c->argv[scoreidx+1]->ptr))        {            zobj = createZsetObject();        } else {            zobj = createZsetZiplistObject();        }        //把key,zobj插入字典        dbAdd(c->db,key,zobj);    //key存在    } else {        //如果不是有序集合,直接返回错误        if (zobj->type != OBJ_ZSET) {            addReply(c,shared.wrongtypeerr);            goto cleanup;        }    }    //elements是
      
       对数    for (j = 0; j < elements; j++) {        double newscore;        score = scores[j];        //retflags设置为前文中的flags变量        int retflags = flags;        ele = c->argv[scoreidx+1+j*2]->ptr;        //每次遍历,score是分数,ele是member.调用zsetadd插入zobj        int retval = zsetAdd(zobj, score, ele, &retflags, &newscore);        if (retval == 0) {            addReplyError(c,nanerr);            goto cleanup;        }        //根据retflags,即一个元素是更新还是新加入,还是未做处理(即member存在,并且        //score值与新设置的一致),更新相应的计数变量(这些变量最后会返回给客户端)        if (retflags & ZADD_ADDED) added++;        if (retflags & ZADD_UPDATED) updated++;        if (!(retflags & ZADD_NOP)) processed++;        score = newscore;    }    server.dirty += (added+updated);//通过命令中的flag,返回给客户端不同的值reply_to_client:    if (incr) { /* ZINCRBY or INCR option. */        if (processed)            addReplyDouble(c,score);        else            addReply(c,shared.nullbulk);    } else { /* ZADD. */        addReplyLongLong(c,ch ? added+updated : added);    }//如果有更新或者新加,需要执行相应的watch key的通知及keyspace的通知cleanup:    zfree(scores);    if (added || updated) {        signalModifiedKey(c->db,key);        notifyKeyspaceEvent(NOTIFY_ZSET,            incr ? "zincr" : "zadd", key, c->db->id);    }}
      
     
    

ZINCRBY

ZINCRBY key increment member

如果key存在,就给相应member的score增加increment

否则直接给key设置分数为increment

//与zadd调用同一个函数,相当于zadd key incr,把incr flag置位void zincrbyCommand(client *c) {    zaddGenericCommand(c,ZADD_INCR);}

ZCARD

ZCARD key

返回有序集合的元素个数

void zcardCommand(client *c) {    robj *key = c->argv[1];    robj *zobj;    //查找key对应的value    if ((zobj = lookupKeyReadOrReply(c,key,shared.czero)) == NULL ||        checkType(c,zobj,OBJ_ZSET)) return;    //通过zsetLength获取zobj中的元素个数    addReplyLongLong(c,zsetLength(zobj));}

unsigned int zsetLength(const robj *zobj) {    int length = -1;    //如果是ziplist,通过zzlLength函数获取长度    //如果长度字段中的值小于UINT16_MAX，直接返回长度。否则需要遍历获取长度    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {        length = zzlLength(zobj->ptr);    //如果是skiplist,直接返回zsl->length    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {        length = ((const zset*)zobj->ptr)->zsl->length;    } else {        serverPanic("Unknown sorted set encoding");    }    return length;}

ZCOUNT

ZCOUNT key min max

返回key中score值在min和max之间的元素个数

其中min和max可以加(,如 zcount key (5 (10

加左括号表示不包含。不加表示包含

void zcountCommand(client *c) {    robj *key = c->argv[1];    robj *zobj;    zrangespec range;    int count = 0;    /* Parse the range arguments */    //判定范围.并将最大最小及是否包含写入range结构体中    if (zslParseRange(c->argv[2],c->argv[3],&range) != C_OK) {        addReplyError(c,"min or max is not a float");        return;    }    /* Lookup the sorted set */    if ((zobj = lookupKeyReadOrReply(c, key, shared.czero)) == NULL ||        checkType(c, zobj, OBJ_ZSET)) return;    //判断zobj底层编码是ziplist还是skiplist    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {        unsigned char *zl = zobj->ptr;        unsigned char *eptr, *sptr;        double score;        //找出第一个在范围之内的元素        /* Use the first element in range as the starting point */        eptr = zzlFirstInRange(zl,&range);        /* No "first" element */        if (eptr == NULL) {            addReply(c, shared.czero);            return;        }        /* First element is in range */        //ziplist中member和score是两个entry,并且member之后保存着score        //整体顺序是按score从小到大排列,score相同时,按member的字典序排列        sptr = ziplistNext(zl,eptr);        //所以此处从第一个元素的下一个entry处获取score        score = zzlGetScore(sptr);        serverAssertWithInfo(c,zobj,zslValueLteMax(score,&range));        /* Iterate over elements in range */        //迭代这个ziplist,如果score满足要求,则count++并且继续迭代,否则跳出        //最后会返回count        while (eptr) {            score = zzlGetScore(sptr);            /* Abort when the node is no longer in range. */            if (!zslValueLteMax(score,&range)) {                break;            } else {                count++;                zzlNext(zl,&eptr,&sptr);            }        }    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {        zset *zs = zobj->ptr;        zskiplist *zsl = zs->zsl;        zskiplistNode *zn;        unsigned long rank;        //如果是跳表,也是先取出第一个元素        /* Find first element in range */        zn = zslFirstInRange(zsl, &range);        /* Use rank of first element, if any, to determine preliminary count */        if (zn != NULL) {            //获取第一个元素的排名            rank = zslGetRank(zsl, zn->score, zn->ele);            count = (zsl->length - (rank - 1));            //如果最大值大于zsl中的最大值,则此count就是要找的个数            /* Find last element in range */            zn = zslLastInRange(zsl, &range);            /* Use rank of last element, if any, to determine the actual count */            if (zn != NULL) {                //如果最大值小于zsl中的最大值，则首先找到最后一个元素的rank                rank = zslGetRank(zsl, zn->score, zn->ele);                //重新计算count,与之前的计算公式合并之后为                //count = (zsl->length-(rankmin-1))-(zsl->length-rankmax))                //      = rankmax-rankmin+1                count -= (zsl->length - rank);            }        }    } else {        serverPanic("Unknown sorted set encoding");    }    //返回count    addReplyLongLong(c, count);}

ZRANGEBYSCORE

ZRANGEBYSCORE key min max WITHSCORES

获取有序结合中分值位于 min和max之间的所有元素

withscores:将member 和 score一起返回

limit offset count:从偏移offset开始获取count个元素

min和max可以为 -inf,+inf,分别表示负无穷和正无穷

//入口函数void zrangebyscoreCommand(client *c) {    genericZrangebyscoreCommand(c,0);}

/* This command implements ZRANGEBYSCORE, ZREVRANGEBYSCORE. */void genericZrangebyscoreCommand(client *c, int reverse) {    zrangespec range;    robj *key = c->argv[1];    robj *zobj;    long offset = 0, limit = -1;    int withscores = 0;    unsigned long rangelen = 0;    void *replylen = NULL;    int minidx, maxidx;    //该函数同时用于zrangbyscore和zrevrangebyscore    //二者通过函数中的reverse参数标识    //正序时第二个参数是min，第三个参数是max,逆序反之    /* Parse the range arguments. */    if (reverse) {        /* Range is given as [max,min] */        maxidx = 2; minidx = 3;    } else {        /* Range is given as [min,max] */        minidx = 2; maxidx = 3;    }    //将参数解析出来赋值到range变量    if (zslParseRange(c->argv[minidx],c->argv[maxidx],&range) != C_OK) {        addReplyError(c,"min or max is not a float");        return;    }    /* Parse optional extra arguments. Note that ZCOUNT will exactly have     * 4 arguments, so we'll never enter the following code path. */    if (c->argc > 4) {        int remaining = c->argc - 4;        int pos = 4;        //解析withscores和limit参数        while (remaining) {            if (remaining >= 1 && !strcasecmp(c->argv[pos]->ptr,"withscores")) {                pos++; remaining--;                withscores = 1;            } else if (remaining >= 3 && !strcasecmp(c->argv[pos]->ptr,"limit")) {                if ((getLongFromObjectOrReply(c, c->argv[pos+1], &offset, NULL)                        != C_OK) ||                    (getLongFromObjectOrReply(c, c->argv[pos+2], &limit, NULL)                        != C_OK))                {                    return;                }                pos += 3; remaining -= 3;            } else {                addReply(c,shared.syntaxerr);                return;            }        }    }    /* Ok, lookup the key and get the range */    if ((zobj = lookupKeyReadOrReply(c,key,shared.emptymultibulk)) == NULL ||        checkType(c,zobj,OBJ_ZSET)) return;    //按zset底层编码是ziplist还是skiplist分别处理    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {        unsigned char *zl = zobj->ptr;        unsigned char *eptr, *sptr;        unsigned char *vstr;        unsigned int vlen;        long long vlong;        double score;        /* If reversed, get the last node in range as starting point. */        //按正序还是逆序分别取最后一个值或者第一个值        if (reverse) {            eptr = zzlLastInRange(zl,&range);        } else {            eptr = zzlFirstInRange(zl,&range);        }        /* No "first" element in the specified interval. */        if (eptr == NULL) {            addReply(c, shared.emptymultibulk);            return;        }        /* Get score pointer for the first element. */        serverAssertWithInfo(c,zobj,eptr != NULL);        sptr = ziplistNext(zl,eptr);        /* We don't know in advance how many matching elements there are in the         * list, so we push this object that will represent the multi-bulk         * length in the output buffer, and will "fix" it later */        replylen = addDeferredMultiBulkLength(c);        /* If there is an offset, just traverse the number of elements without         * checking the score because that is done in the next loop. */        //如果有offset,先偏移相应的元素        //注意此处zzlNext传入了两个指针,会一次偏移一个
    
     对        //注意此处offset初始值是0,如果没指定则不会进入此处循环        while (eptr && offset--) {            if (reverse) {                zzlPrev(zl,&eptr,&sptr);            } else {                zzlNext(zl,&eptr,&sptr);            }        }        //如果有limit,则进入循环.取limit次.limit的初始值为-1,即使没指定,也会进入循环        //直到eptr为null或者循环中break掉        while (eptr && limit--) {            score = zzlGetScore(sptr);            /* Abort when the node is no longer in range. */            //不在范围之内时break掉            if (reverse) {                if (!zslValueGteMin(score,&range)) break;            } else {                if (!zslValueLteMax(score,&range)) break;            }            /* We know the element exists, so ziplistGet should always succeed */            serverAssertWithInfo(c,zobj,ziplistGet(eptr,&vstr,&vlen,&vlong));            //取出相应的值.可能为str,赋值给vstr,长度为vlen,或者为整型,赋值给vlong            rangelen++;            if (vstr == NULL) {                addReplyBulkLongLong(c,vlong);            } else {                addReplyBulkCBuffer(c,vstr,vlen);            }            //如果设置了withscores标志,则返回分数            if (withscores) {                addReplyDouble(c,score);            }            //开始迭代下一个节点            /* Move to next node */            if (reverse) {                zzlPrev(zl,&eptr,&sptr);            } else {                zzlNext(zl,&eptr,&sptr);            }        }    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {        zset *zs = zobj->ptr;        zskiplist *zsl = zs->zsl;        zskiplistNode *ln;        //同ziplist,先查找起始或最终节点        /* If reversed, get the last node in range as starting point. */        if (reverse) {            ln = zslLastInRange(zsl,&range);        } else {            ln = zslFirstInRange(zsl,&range);        }        /* No "first" element in the specified interval. */        if (ln == NULL) {            addReply(c, shared.emptymultibulk);            return;        }        /* We don't know in advance how many matching elements there are in the         * list, so we push this object that will represent the multi-bulk         * length in the output buffer, and will "fix" it later */        //返回客户端时先返回元素个数,但此处并不知道需要返回多少个元素,所以先占个位置        //replylen是存储len字段的指针        replylen = addDeferredMultiBulkLength(c);        /* If there is an offset, just traverse the number of elements without         * checking the score because that is done in the next loop. */        //处理offset.向前或向后skip        while (ln && offset--) {            if (reverse) {                ln = ln->backward;            } else {                ln = ln->level[0].forward;            }        }        //处理limit        while (ln && limit--) {            /* Abort when the node is no longer in range. */            if (reverse) {                if (!zslValueGteMin(ln->score,&range)) break;            } else {                if (!zslValueLteMax(ln->score,&range)) break;            }            rangelen++;            addReplyBulkCBuffer(c,ln->ele,sdslen(ln->ele));            if (withscores) {                addReplyDouble(c,ln->score);            }            /* Move to next node */            if (reverse) {                ln = ln->backward;            } else {                ln = ln->level[0].forward;            }        }    } else {        serverPanic("Unknown sorted set encoding");    }    //如果有withscores参数,返回给客户端的字符串数量是2倍    if (withscores) {        rangelen *= 2;    }    //将rangelen放入replylen指向的位置,返回给客户端    setDeferredMultiBulkLength(c, replylen, rangelen);}
    

ZRANK

ZRANK key member

返回有序集合中元素member的rank

以0为起始rank,元素分数从低到高

zrevrank,元素分数从高到低

void zrankGenericCommand(client *c, int reverse) {    robj *key = c->argv[1];    robj *ele = c->argv[2];    robj *zobj;    long rank;    //通过key找出有序集合的value zobj    if ((zobj = lookupKeyReadOrReply(c,key,shared.nullbulk)) == NULL ||        checkType(c,zobj,OBJ_ZSET)) return;    serverAssertWithInfo(c,ele,sdsEncodedObject(ele));    //在zobj中查找ele(第二个参数member)    rank = zsetRank(zobj,ele->ptr,reverse);    if (rank >= 0) {        addReplyLongLong(c,rank);    } else {        addReply(c,shared.nullbulk);    }}void zrankCommand(client *c) {    zrankGenericCommand(c, 0);}

long zsetRank(robj *zobj, sds ele, int reverse) {    unsigned long llen;    unsigned long rank;    llen = zsetLength(zobj);    //ziplist从前往后遍历,比较entry中的元素与ele,每次将rank++    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {        unsigned char *zl = zobj->ptr;        unsigned char *eptr, *sptr;        eptr = ziplistIndex(zl,0);        serverAssert(eptr != NULL);        sptr = ziplistNext(zl,eptr);        serverAssert(sptr != NULL);        rank = 1;        while(eptr != NULL) {            if (ziplistCompare(eptr,(unsigned char*)ele,sdslen(ele)))                break;            rank++;            zzlNext(zl,&eptr,&sptr);        }        if (eptr != NULL) {            //如果是逆序取,直接将llen-rank就是逆向的rank            if (reverse)                return llen-rank;            else                return rank-1;        } else {            return -1;        }    //skiplist通过zslGetRank获取rank,具体过程为跳表查找,将相应路过节点的span相加    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {        zset *zs = zobj->ptr;        zskiplist *zsl = zs->zsl;        dictEntry *de;        double score;        de = dictFind(zs->dict,ele);        if (de != NULL) {            score = *(double*)dictGetVal(de);            rank = zslGetRank(zsl,score,ele);            /* Existing elements always have a rank. */            serverAssert(rank != 0);            //逆向取rank            if (reverse)                return llen-rank;            else                return rank-1;        } else {            return -1;        }    } else {        serverPanic("Unknown sorted set encoding");    }}

ZREM

ZREM key member [member ...]

从有序集合中删除相应的member

void zremCommand(client *c) {    robj *key = c->argv[1];    robj *zobj;    int deleted = 0, keyremoved = 0, j;    //根据key找到对应的zobj    if ((zobj = lookupKeyWriteOrReply(c,key,shared.czero)) == NULL ||        checkType(c,zobj,OBJ_ZSET)) return;    //依次删除相应的元素,每次删除之后检查zset是否为空,如果为空,删掉该key,并且break    for (j = 2; j < c->argc; j++) {        if (zsetDel(zobj,c->argv[j]->ptr)) deleted++;        if (zsetLength(zobj) == 0) {            dbDelete(c->db,key);            keyremoved = 1;            break;        }    }    //如果确实有member被删除掉,通知keyspace zrem事件    //如果zset整个都被删除了,通知keyspace del事件    if (deleted) {        notifyKeyspaceEvent(NOTIFY_ZSET,"zrem",key,c->db->id);        if (keyremoved)            notifyKeyspaceEvent(NOTIFY_GENERIC,"del",key,c->db->id);        signalModifiedKey(c->db,key);        server.dirty += deleted;    }    //返回给客户端实际删除的member个数    addReplyLongLong(c,deleted);}

/* Delete the element 'ele' from the sorted set, returning 1 if the element * existed and was deleted, 0 otherwise (the element was not there). */int zsetDel(robj *zobj, sds ele) {    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {        unsigned char *eptr;        //ziplist先找到ele所在位置的指针eptr        if ((eptr = zzlFind(zobj->ptr,ele,NULL)) != NULL) {            //将该元素删除.ziplist删除时会resize,此处将删除之后ziplist的指针复值给zobj->ptr            zobj->ptr = zzlDelete(zobj->ptr,eptr);            return 1;        }    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {        zset *zs = zobj->ptr;        dictEntry *de;        double score;        //skiplist现将zobj->ptr->dict相应的ele删除掉。此处并未真实删除        //而是将ele所在的dictEntry返回        de = dictUnlink(zs->dict,ele);        if (de != NULL) {            /* Get the score in order to delete from the skiplist later. */            //通过dictEntry获取score            score = *(double*)dictGetVal(de);            /* Delete from the hash table and later from the skiplist.             * Note that the order is important: deleting from the skiplist             * actually releases the SDS string representing the element,             * which is shared between the skiplist and the hash table, so             * we need to delete from the skiplist as the final step. */            //此处将dict中的key和value实际free掉            dictFreeUnlinkedEntry(zs->dict,de);            /* Delete from skiplist. */            //从skiplist中删除元素.ele这个sds在hash和skiplist共享.从skiplist中删除时            //会释放此sds,所以必须先删除dict中的元素再删除skiplist中的元素            int retval = zslDelete(zs->zsl,score,ele,NULL);            serverAssert(retval);            //如果hash表中元素使用率小于10%,进行dict的resize            if (htNeedsResize(zs->dict)) dictResize(zs->dict);            return 1;        }    } else {        serverPanic("Unknown sorted set encoding");    }    return 0; /* No such element found. */}