16.2 太牛了！分库分表和智能分片竟然还能这样实现？
在分布式任务调度系统中，随着业务规模的增长，单一数据库往往无法满足海量数据存储和高并发访问的需求。分库分表技术是解决这一问题的关键手段。今天我们将深入探讨如何实现分库分表和智能分片策略。
分库分表架构设计
分库分表是一种将数据分散存储在多个数据库和表中的技术，能够有效提升系统的存储容量和并发处理能力。
packageshardingimport("database/sql""fmt""hash/crc32""math""sort""strconv""strings""sync""time")// ShardingConfig 分库分表配置typeShardingConfigstruct{DatabaseCountintTableCountintShardingKeystringShardingType ShardingType DatabasePrefixstringTablePrefixstring}// ShardingType 分片类型typeShardingTypeintconst(ShardingTypeMod ShardingType=iota// 取模分片ShardingTypeRange// 范围分片ShardingTypeHash// 哈希分片)// ShardingManager 分库分表管理器typeShardingManagerstruct{config*ShardingConfig databasesmap[string]*sql.DB mutex sync.RWMutex router*ShardingRouter}// ShardingRouter 分片路由typeShardingRouterstruct{config*ShardingConfig}// NewShardingManager 创建分库分表管理器funcNewShardingManager(config*ShardingConfig)*ShardingManager{router:=&ShardingRouter{config:config,}return&ShardingManager{config:config,databases:make(map[string]*sql.DB),router:router,}}// AddDatabase 添加数据库连接func(sm*ShardingManager)AddDatabase(dbNamestring,db*sql.DB){sm.mutex.Lock()defersm.mutex.Unlock()sm.databases[dbName]=db}// GetDatabase 获取数据库连接func(sm*ShardingManager)GetDatabase(dbIndexint)(*sql.DB,error){sm.mutex.RLock()defersm.mutex.RUnlock()dbName:=fmt.Sprintf("%s_%d",sm.config.DatabasePrefix,dbIndex)db,exists:=sm.databases[dbName]if!exists{returnnil,fmt.Errorf("database %s not found",dbName)}returndb,nil}// Route 路由分片func(sm*ShardingManager)Route(shardingValueinterface{})(*ShardLocation,error){returnsm.router.Route(shardingValue)}// ShardLocation 分片位置typeShardLocationstruct{DatabaseIndexintTableIndexintDatabaseNamestringTableNamestring}// Route 路由分片func(sr*ShardingRouter)Route(shardingValueinterface{})(*ShardLocation,error){vardbIndex,tableIndexintswitchsr.config.ShardingType{caseShardingTypeMod:dbIndex,tableIndex=sr.modSharding(shardingValue)caseShardingTypeRange:dbIndex,tableIndex=sr.rangeSharding(shardingValue)caseShardingTypeHash:dbIndex,tableIndex=sr.hashSharding(shardingValue)default:returnnil,fmt.Errorf("unsupported sharding type: %v",sr.config.ShardingType)}location:=&ShardLocation{DatabaseIndex:dbIndex,TableIndex:tableIndex,DatabaseName:fmt.Sprintf("%s_%d",sr.config.DatabasePrefix,dbIndex),TableName:fmt.Sprintf("%s_%d",sr.config.TablePrefix,tableIndex),}returnlocation,nil}// modSharding 取模分片func(sr*ShardingRouter)modSharding(shardingValueinterface{})(int,int){// 将分片值转换为整数varvalueint64switchv:=shardingValue.(type){caseint:value=int64(v)caseint64:value=vcasestring:// 对字符串进行哈希value=int64(crc32.ChecksumIEEE([]byte(v)))default:// 默认使用字符串表示value=int64(crc32.ChecksumIEEE([]byte(fmt.Sprintf("%v",v))))}// 计算数据库和表索引dbIndex:=int(value%int64(sr.config.DatabaseCount))tableIndex:=int((value/int64(sr.config.DatabaseCount))%int64(sr.config.TableCount))returndbIndex,tableIndex}// rangeSharding 范围分片func(sr*ShardingRouter)rangeSharding(shardingValueinterface{})(int,int){varvalueint64switchv:=shardingValue.(type){caseint:value=int64(v)caseint64:value=vcasestring:// 尝试解析为整数ifi,err:=strconv.ParseInt(v,10,64);err==nil{value=i}else{// 否则使用哈希value=int64(crc32.ChecksumIEEE([]byte(v)))}default:// 默认使用字符串表示ifs,ok:=v.(fmt.Stringer);ok{ifi,err:=strconv.ParseInt(s.String(),10,64);err==nil{value=i}else{value=int64(crc32.ChecksumIEEE([]byte(s.String())))}}else{value=int64(crc32.ChecksumIEEE([]byte(fmt.Sprintf
