搞定了 6 种分布式ID，分库分表哪个适合做主键？

CREATE TABLE `t_order` (
  `id` bigint NOT NULL,
  `order_id` bigint NOT NULL,
  `user_id` bigint NOT NULL,
  `order_number` varchar(255) COLLATE utf8mb4_general_ci NOT NULL,
  `customer_id` bigint NOT NULL,
  `order_date` datetime DEFAULT NULL,
  `interval_value` varchar(125) COLLATE utf8mb4_general_ci DEFAULT NULL,
  `total_amount` decimal(10,2) NOT NULL,
  PRIMARY KEY (`order_id`) USING BTREE
) ;

spring:
  shardingsphere:
    rules:
      sharding:
        key-generators:  # 分布式序列算法配置
          # UUID生成算法
          uu-id-gen:
            type: UUID
        tables:
          t_order:  # 逻辑表名称
            actual-data-nodes: db$->{0..1}.t_order_${0..2} # 数据节点：数据库.分片表
            database-strategy:  # 分库策略
              standard:
                sharding-column: order_id
                sharding-algorithm-name: t_order_database_mod
            table-strategy: # 分表策略
              standard:
                sharding-column: order_id
                sharding-algorithm-name: t_order_table_mod
            key-generate-strategy: # 分布式主键生成策略
              column: id
              keyGeneratorName: uu-id-gen

spring:
  shardingsphere:
    rules:
      sharding:
        key-generators:  # 分布式序列算法配置
          # nanoid生成算法
          nanoid-gen:
            type: NANOID
        tables:
          t_order:  # 逻辑表名称
            actual-data-nodes: db$->{0..1}.t_order_${0..2} # 数据节点：数据库.分片表
            key-generate-strategy: # 分布式主键生成策略
              column: id
              keyGeneratorName: nanoid-gen

@Override
  public synchronized Long generateKey() {
      ..........
      return ((currentMilliseconds - EPOCH) << TIMESTAMP_LEFT_SHIFT_BITS) | (getWorkerId() << WORKER_ID_LEFT_SHIFT_BITS) | sequence;
  }

private void vibrateSequenceOffset() {
    sequenceOffset = sequenceOffset >= maxVibrationOffset ? 0 : sequenceOffset + 1;
}

@SneakyThrows(InterruptedException.class)
private boolean waitTolerateTimeDifferenceIfNeed(final long currentMilliseconds) {
    if (lastMilliseconds <= currentMilliseconds) {
        return false;
    }
    long timeDifferenceMilliseconds = lastMilliseconds - currentMilliseconds;
    Preconditions.checkState(timeDifferenceMilliseconds < maxTolerateTimeDifferenceMilliseconds,
            "Clock is moving backwards, last time is %d milliseconds, current time is %d milliseconds", lastMilliseconds, currentMilliseconds);
    Thread.sleep(timeDifferenceMilliseconds);
    return true;
}

spring:
  shardingsphere:
    rules:
      sharding:
        key-generators:  # 分布式序列算法配置
          # 雪花ID生成算法
          snowflake-gen:
            type: SNOWFLAKE
            props:
              worker-id: # 工作机器唯一标识
              max-vibration-offset: 1024 # 最大抖动上限值，范围[0, 4096)。注：若使用此算法生成值作分片值，建议配置此属性。此算法在不同毫秒内所生成的 key 取模 2^n (2^n一般为分库或分表数) 之后结果总为 0 或 1。为防止上述分片问题，建议将此属性值配置为 (2^n)-1
              max-tolerate-time-difference-milliseconds: 10 # 最大容忍时钟回退时间，单位：毫秒
        tables:
          t_order:  # 逻辑表名称
            actual-data-nodes: db$->{0..1}.t_order_${0..2} # 数据节点：数据库.分片表
            key-generate-strategy: # 分布式主键生成策略
              column: id
              keyGeneratorName: snowflake-gen

spring:
  shardingsphere:
    rules:
      sharding:
        key-generators:  # 分布式序列算法配置
          # COSID生成算法
          cosId-gen:
            type: COSID
            props:
              id-name: share
              as-string: false
        tables:
          t_order:  # 逻辑表名称
            actual-data-nodes: db$->{0..1}.t_order_${0..2} # 数据节点：数据库.分片表
            key-generate-strategy: # 分布式主键生成策略
              column: id
              keyGeneratorName: cosId-gen

public synchronized long generate() {
    long currentTimestamp = this.getCurrentTime();
    if (currentTimestamp < this.lastTimestamp) {
        throw new ClockBackwardsException(this.lastTimestamp, currentTimestamp);
    } else {
        if (currentTimestamp > this.lastTimestamp && this.sequence >= this.sequenceResetThreshold) {
            this.sequence = 0L;
        }

        this.sequence = this.sequence + 1L & this.maxSequence;
        if (this.sequence == 0L) {
            currentTimestamp = this.nextTime();
        }

        this.lastTimestamp = currentTimestamp;
        long diffTimestamp = currentTimestamp - this.epoch;
        if (diffTimestamp > this.maxTimestamp) {
            throw new TimestampOverflowException(this.epoch, diffTimestamp, this.maxTimestamp);
        } else {
            return diffTimestamp << (int)this.timestampLeft | this.machineId << (int)this.machineLeft | this.sequence;
        }
    }
}

spring:
  shardingsphere:
    rules:
      sharding:
        key-generators:  # 分布式序列算法配置
          # cosId-snowflake生成算法
          cosId-snowflake-gen:
            type: COSID_SNOWFLAKE
            props:
              epoch: 1477929600000
              as-string: false
        tables:
          t_order:  # 逻辑表名称
            actual-data-nodes: db$->{0..1}.t_order_${0..2} # 数据节点：数据库.分片表
            key-generate-strategy: # 分布式主键生成策略
              column: id
              keyGeneratorName: cosId-snowflake-gen

@Data
@Slf4j
public class SequenceAlgorithms implements KeyGenerateAlgorithm {

    // 这个方法用于指定我们自定义的算法的类型。它会返回一个字符串，表示所使用算法的类型，方便在配置和识别时使用。
    @Override
    public String getType() {
        // 返回算法类型表示
        return "custom";
    }

    // 这是生成主键的核心逻辑所在。在这个方法内部，我们可以根据业务需求选择合适的主键生成算法，比如美团的Leaf、滴滴的TinyId等。这个方法的具体实现会根据所选算法的特点和要求来设计
    @Override
    public Comparable<?> generateKey() {
        return null;
    }

    @Override
    public Properties getProps() {
        return null;
    }
    // 这个方法用于初始化主键生成算法所需的资源或配置
    @Override
    public void init(Properties properties) {
    }
}

resource
    |_META-INF
        |_services
           |_org.apache.shardingsphere.sharding.spi.KeyGenerateAlgorithm

spring:
  shardingsphere:
    rules:
      sharding:
        key-generators:  # 分布式序列算法配置
          # 自定义ID生成策略
          xiaofu-id-gen:
            type: custom
        tables:
          t_order:  # 逻辑表名称
            actual-data-nodes: db$->{0..1}.t_order_${0..2} # 数据节点：数据库.分片表
            key-generate-strategy: # 分布式主键生成策略
              column: id
              keyGeneratorName: xiaofu-id-gen