IdGenerator

Seata 优化的雪花算法

csharp 移植代码

    public class IdGenerator
    {
        private readonly long twepoch = 1588435200000L;
        private const int workerIdBits = 10;
        private const int timestampBits = 41;
        private const int sequenceBits = 12;
        private const int maxWorkerId = ~(-1 << workerIdBits);
        private long workerId;
        private long timestampAndSequence;
        private readonly long timestampAndSequenceMask = ~(-1L << (timestampBits + sequenceBits));

        public static readonly IdGenerator Instance = new IdGenerator(GenerateWorkerId());

        public IdGenerator(long workerId)
        {
            InitTimestampAndSequence();
            InitWorkerId(workerId);
        }

        private void InitTimestampAndSequence()
        {
            long timestamp = GetNewestTimestamp();
            long timestampWithSequence = timestamp << sequenceBits;
            this.timestampAndSequence = timestampWithSequence;
        }

        private void InitWorkerId(long workerId)
        {
            if (workerId > maxWorkerId || workerId < 0)
            {
                string message = string.Format("worker Id can't be greater than {0} or less than 0", maxWorkerId);
                throw new ArgumentException(message);
            }
            this.workerId = workerId << (timestampBits + sequenceBits);
        }

        public long NextId()
        {
            WaitIfNecessary();
            long next = Interlocked.Increment(ref timestampAndSequence);
            long timestampWithSequence = next & timestampAndSequenceMask;
            return workerId | timestampWithSequence;
        }

        public static long NewId()
        {
            return Instance.NextId();
        }

        private void WaitIfNecessary()
        {
            long currentWithSequence = timestampAndSequence;
            long current = currentWithSequence >> sequenceBits;
            long newest = GetNewestTimestamp();
            if (current >= newest)
            {
                Thread.Sleep(5);
            }
        }

        private long GetNewestTimestamp()
        {
            return DateTimeOffset.UtcNow.ToUnixTimeMilliseconds() - twepoch;
        }

        public static long GenerateWorkerId()
        {
            try
            {
                return GenerateWorkerIdBaseOnK8S();
            }
            catch (Exception)
            {
                try
                {
                    return GenerateWorkerIdBaseOnMac();
                }
                catch (Exception)
                {
                    return GenerateRandomWorkerId();
                }
            }
        }

        public static long GenerateWorkerIdBaseOnMac()
        {
            IEnumerable<NetworkInterface> all = NetworkInterface.GetAllNetworkInterfaces();
            foreach (NetworkInterface networkInterface in all)
            {
                bool isLoopback = networkInterface.NetworkInterfaceType == NetworkInterfaceType.Loopback;
                //bool isVirtual = networkInterface.;
                //if (isLoopback || isVirtual)
                if (isLoopback)
                {
                    continue;
                }
                byte[] mac = networkInterface.GetPhysicalAddress().GetAddressBytes();
                return ((mac[4] & 0B11) << 8) | (mac[5] & 0xFF);
            }
            throw new Exception("no available mac found");
        }

        public static long GenerateWorkerIdBaseOnK8S()
        {
            return GenerateWorkerIdBaseOnString(Environment.GetEnvironmentVariable("K8S_POD_ID"));
        }

        public static long GenerateWorkerIdBaseOnString(string str)
        {
            ArgumentNullException.ThrowIfNull(str, nameof(str));
            int hashValue = 0;
            int cc = 2 << (workerIdBits - 1);
            foreach (char c in str)
            {
                hashValue = (hashValue * 31 + c) % cc;
            }
            return hashValue + 1;
        }

        public static long GenerateRandomWorkerId()
        {
            return Random.Shared.NextInt64(maxWorkerId + 1);
        }
    }

YitIdHelper

开源库 https://github.com/yitter/IdGenerator

❄ 这是优化的雪花算法（雪花漂移），它生成的ID更短、速度更快。

❄ 支持 k8s 等容器环境自动扩容（自动注册 WorkerId），可在单机或分布式环境生成数字型唯一ID。

Guid

https://learn.microsoft.com/zh-cn/dotnet/api/system.guid?view=net-7.0

全局唯一标识符（GUID，Globally Unique Identifier）是一种由算法生成的二进制长度为128位的数字标识符。GUID主要用于在拥有多个节点、多台计算机的网络或系统中。

Nanoid

开源库 https://github.com/codeyu/nanoid-net

一个小巧、安全、URL友好、唯一的字符串ID生成器。

“一个惊人的无意义的完美主义水平，这简直让人无法不敬佩。”

小巧. 130字节 (经过压缩和gzip处理)。没有依赖。Size Limit 控制大小。
安全. 它使用硬件随机生成器。可在集群中使用。
紧凑. 它使用比 UUID（A-Za-z0-9_-）更大的字母表。因此，ID 大小从36个符号减少到21个符号。
可移植. Nano ID 已被移植到 20种编程语言。

Nano ID 与 UUID v4 (基于随机数) 相当。它们在 ID 中有相似数量的随机位 (Nano ID 为126，UUID 为122),因此它们的碰撞概率相似：:

要想有十亿分之一的重复机会, 必须产生103万亿个版本4的ID.

Nano ID 和 UUID v4之间有两个主要区别:

Nano ID 使用更大的字母表，所以类似数量的随机位被包装在21个符号中，而不是36个。
Nano ID 代码比 uuid/v4 包少 4倍: 130字节而不是423字节.

性能测试代码

[AllStatisticsColumn]
public class IdGeneratorTest
{
    public IdGeneratorTest()
    {
        var options = new IdGeneratorOptions()
        {
            WorkerId = 55,
            WorkerIdBitLength = 6,
            SeqBitLength = 12,
        };
        YitIdHelper.SetIdGenerator(options);
    }

    [Benchmark]
    public long IdGeneratorNewId() => IdGenerator.NewId();


    [Benchmark]
    public long YitIdHelperNextId() => YitIdHelper.NextId();

    [Benchmark]
    public string NewGuid() => Guid.NewGuid().ToString();

    [Benchmark]
    public string NanoidGenerate() => Nanoid.Generate();
}

结果


BenchmarkDotNet v0.13.10, Windows 11 (10.0.22000.2538/21H2/SunValley)
Intel Core i7-10700 CPU 2.90GHz, 1 CPU, 16 logical and 8 physical cores
.NET SDK 7.0.403
  [Host]     : .NET 6.0.24 (6.0.2423.51814), X64 RyuJIT AVX2
  DefaultJob : .NET 6.0.24 (6.0.2423.51814), X64 RyuJIT AVX2

Method	Mean	Error	StdDev	StdErr	Median	Min	Q1	Q3	Max	Op/s
IdGeneratorNewId	243.3 ns	1.33 ns	1.25 ns	0.32 ns	243.0 ns	241.42 ns	242.32 ns	244.3 ns	246.1 ns	4,109,814.4
YitIdHelperNextId	241.7 ns	66.08 ns	194.85 ns	19.48 ns	430.2 ns	43.51 ns	43.83 ns	431.8 ns	432.7 ns	4,137,225.0
NewGuid	179.5 ns	3.63 ns	6.06 ns	1.01 ns	177.1 ns	173.10 ns	175.06 ns	182.5 ns	193.3 ns	5,572,366.5
NanoidGenerate	188.6 ns	4.30 ns	12.21 ns	1.27 ns	185.1 ns	174.49 ns	179.40 ns	195.5 ns	219.8 ns	5,301,348.8