Redis源码分析之set 和 sorted set 使用_Redis_

# 向集合添加一个或多个成员 SADD key member1 [member2] # 获取集合的成员数 SCARD key # 返回第一个集合与其他集合之间的差异。 SDIFF key1 [key2] # 返回给定所有集合的差集并存储在 destination 中 SDIFFSTORE destination key1 [key2] # 返回给定所有集合的交集 SINTER key1 [key2] # 返回给定所有集合的交集并存储在 destination 中 SINTERSTORE destination key1 [key2] # 判断 member 元素是否是集合 key 的成员 SISMEMBER key member # 返回集合中的所有成员 SMEMBERS key # 将 member 元素从 source 集合移动到 destination 集合 SMOVE source destination member # 移除并返回集合中的一个随机元素 SPOP key # 返回集合中一个或多个随机数 SRANDMEMBER key [count] # 移除集合中一个或多个成员 SREM key member1 [member2] # 返回所有给定集合的并集 SUNION key1 [key2] # 所有给定集合的并集存储在 destination 集合中 SUNIONSTORE destination key1 [key2] # 迭代集合中的元素 SSCAN key cursor [MATCH pattern] [COUNT count]

127.0.0.1:6379> SADD set-test xiaoming (integer) 1 (integer) 0 127.0.0.1:6379> SADD set-test xiaoming1 127.0.0.1:6379> SADD set-test xiaoming2 127.0.0.1:6379> SMEMBERS set-test 1) "xiaoming2" 2) "xiaoming" 3) "xiaoming1"

void saddCommand(client *c) { robj *set; int j, added = 0; set = lookupKeyWrite(c->db,c->argv[1]); if (checkType(c,set,OBJ_SET)) return; if (set == NULL) { set = setTypeCreate(c->argv[2]->ptr); dbAdd(c->db,c->argv[1],set); } for (j = 2; j < c->argc; j++) { if (setTypeAdd(set,c->argv[j]->ptr)) added++; if (added) { signalModifiedKey(c,c->db,c->argv[1]); notifyKeyspaceEvent(NOTIFY_SET,"sadd",c->argv[1],c->db->id); server.dirty += added; addReplyLongLong(c,added); } // 当 value 是整数类型使用 intset // 否则使用哈希表 robj *setTypeCreate(sds value) { if (isSdsRepresentableAsLongLong(value,NULL) == C_OK) return createIntsetObject(); return createSetObject(); /* Add the specified value into a set. * * If the value was already member of the set, nothing is done and 0 is * returned, otherwise the new element is added and 1 is returned. */ int setTypeAdd(robj *subject, sds value) { long long llval; // 如果是 OBJ_ENCODING_HT 说明是哈希类型 if (subject->encoding == OBJ_ENCODING_HT) { dict *ht = subject->ptr; dictEntry *de = dictAddRaw(ht,value,NULL); if (de) { // 设置key ,value 设置成null dictSetKey(ht,de,sdsdup(value)); dictSetVal(ht,de,NULL); return 1; } // OBJ_ENCODING_INTSET 代表是 inset } else if (subject->encoding == OBJ_ENCODING_INTSET) { if (isSdsRepresentableAsLongLong(value,&llval) == C_OK) { uint8_t success = 0; subject->ptr = intsetAdd(subject->ptr,llval,&success); if (success) { /* Convert to regular set when the intset contains * too many entries. */ // 如果条目过多将会转换成集合 size_t max_entries = server.set_max_intset_entries; /* limit to 1G entries due to intset internals. */ if (max_entries >= 1<<30) max_entries = 1<<30; if (intsetLen(subject->ptr) > max_entries) setTypeConvert(subject,OBJ_ENCODING_HT); return 1; } } else { /* Failed to get integer from object, convert to regular set. */ setTypeConvert(subject,OBJ_ENCODING_HT); /* The set *was* an intset and this value is not integer * encodable, so dictAdd should always work. */ serverAssert(dictAdd(subject->ptr,sdsdup(value),NULL) == DICT_OK); } else { serverPanic("Unknown set encoding"); return 0;

typedef struct intset { // 编码方法，指定当前存储的是 16 位，32 位，还是 64 位的整数 uint32_t encoding; uint32_t length; // 实际保存元素的数组 int8_t contents[]; } intset;

/* Insert an integer in the intset */ intset *intsetAdd(intset *is, int64_t value, uint8_t *success) { // 计算value的编码长度 uint8_t valenc = _intsetValueEncoding(value); uint32_t pos; if (success) *success = 1; /* Upgrade encoding if necessary. If we need to upgrade, we know that * this value should be either appended (if > 0) or prepended (if < 0), * because it lies outside the range of existing values. */ // 如果value的编码长度大于当前的编码位数，进行升级 if (valenc > intrev32ifbe(is->encoding)) { /* This always succeeds, so we don't need to curry *success. */ return intsetUpgradeAndAdd(is,value); } else { /* Abort if the value is already present in the set. * This call will populate "pos" with the right position to insert * the value when it cannot be found. */ // 当前值不存在的时候才进行插入 if (intsetSearch(is,value,&pos)) { if (success) *success = 0; return is; } is = intsetResize(is,intrev32ifbe(is->length)+1); if (pos < intrev32ifbe(is->length)) intsetMoveTail(is,pos,pos+1); } // 数据插入 _intsetSet(is,pos,value); is->length = intrev32ifbe(intrev32ifbe(is->length)+1); return is; }

/* Search for the position of "value". Return 1 when the value was found and * sets "pos" to the position of the value within the intset. Return 0 when * the value is not present in the intset and sets "pos" to the position * where "value" can be inserted. */ // 如果找到了对应的数据，返回 1 将 pos 设置为对应的位置 // 如果找不到，返回0，设置 pos 为可以为数据可以插入的位置 // intset 中的数据是排好序的，所以使用二分查找来寻找对应的元素 static uint8_t intsetSearch(intset *is, int64_t value, uint32_t *pos) { int min = 0, max = intrev32ifbe(is->length)-1, mid = -1; int64_t cur = -1; /* The value can never be found when the set is empty */ if (intrev32ifbe(is->length) == 0) { if (pos) *pos = 0; return 0; } else { /* Check for the case where we know we cannot find the value, * but do know the insert position. */ if (value > _intsetGet(is,max)) { if (pos) *pos = intrev32ifbe(is->length); return 0; } else if (value < _intsetGet(is,0)) { if (pos) *pos = 0; } } // 使用二分查找 while(max >= min) { mid = ((unsigned int)min + (unsigned int)max) >> 1; cur = _intsetGet(is,mid); if (value > cur) { min = mid+1; } else if (value < cur) { max = mid-1; } else { break; if (value == cur) { if (pos) *pos = mid; return 1; if (pos) *pos = min; }

typedef struct dict { dictType *type; void *privdata; // 哈希表数组，长度为2，一个正常存储数据，一个用来扩容 dictht ht[2]; long rehashidx; /* rehashing not in progress if rehashidx == -1 */ int16_t pauserehash; /* If >0 rehashing is paused (<0 indicates coding error) */ } dict; // 哈希表结构，通过两个哈希表使用，实现增量的 rehash typedef struct dictht { dictEntry **table; // hash 容量大小 unsigned long size; // 总是等于 size - 1，用于计算索引值 unsigned long sizemask; // 实际存储的 dictEntry 数量 unsigned long used; } dictht; // k/v 键值对节点，是实际存储数据的节点 typedef struct dictEntry { // 键对象，总是一个字符串类型的对象 void *key; union { // void指针，这意味着它可以指向任何类型 void *val; uint64_t u64; int64_t s64; double d; } v; // 指向下一个节点 struct dictEntry *next; } dictEntry;

dictEntry *dictAddRaw(dict *d, void *key, dictEntry **existing) { long index; dictEntry *entry; dictht *ht; if (dictIsRehashing(d)) _dictRehashStep(d); /* Get the index of the new element, or -1 if * the element already exists. */ if ((index = _dictKeyIndex(d, key, dictHashKey(d,key), existing)) == -1) return NULL; /* Allocate the memory and store the new entry. * Insert the element in top, with the assumption that in a database * system it is more likely that recently added entries are accessed * more frequently. */ // 这里来判断是否正在 Rehash 中 ht = dictIsRehashing(d) ? &d->ht[1] : &d->ht[0]; entry = zmalloc(sizeof(*entry)); entry->next = ht->table[index]; ht->table[index] = entry; ht->used++; /* Set the hash entry 
                
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