分布式唯一ID生成器Twitter 的 Snowflake idworker有谁在用么

Question

Snowflake idworker在分布式部署到不同IDC服务器的时候，是否需要修改参数或配置才能达到产生的ID才会不重复？
[code="java"]

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**

• @author zhujuan
• From: https://github.com/twitter/snowflake
• An object that generates IDs.
• This is broken into a separate class in case
• we ever want to support multiple worker threads

• per process
  */
  public class IdWorker {

  protected static final Logger LOG = LoggerFactory.getLogger(IdWorker.class);

  private long workerId;
  private long datacenterId;
  private long sequence = 0L;

  private long twepoch = 1288834974657L;

  private long workerIdBits = 5L;
  private long datacenterIdBits = 5L;
  private long maxWorkerId = -1L ^ (-1L << workerIdBits);
  private long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
  private long sequenceBits = 12L;

  private long workerIdShift = sequenceBits;
  private long datacenterIdShift = sequenceBits + workerIdBits;
  private long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
  private long sequenceMask = -1L ^ (-1L << sequenceBits);

  private long lastTimestamp = -1L;

  public IdWorker(long workerId, long datacenterId) {
  // sanity check for workerId
  if (workerId > maxWorkerId || workerId < 0) {
  throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));
  }
  if (datacenterId > maxDatacenterId || datacenterId < 0) {
  throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));
  }
  this.workerId = workerId;
  this.datacenterId = datacenterId;
  LOG.info(String.format("worker starting. timestamp left shift %d, datacenter id bits %d, worker id bits %d, sequence bits %d, workerid %d", timestampLeftShift, datacenterIdBits, workerIdBits, sequenceBits, workerId));
  }

  public synchronized long nextId() {
  long timestamp = timeGen();

  if (timestamp < lastTimestamp) {
      LOG.error(String.format("clock is moving backwards.  Rejecting requests until %d.", lastTimestamp));
      throw new RuntimeException(String.format("Clock moved backwards.  Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
  }
  
  if (lastTimestamp == timestamp) {
      sequence = (sequence + 1) & sequenceMask;
      if (sequence == 0) {
          timestamp = tilNextMillis(lastTimestamp);
      }
  } else {
      sequence = 0L;
  }
  
  lastTimestamp = timestamp;
  
  return ((timestamp - twepoch) << timestampLeftShift) | (datacenterId << datacenterIdShift) | (workerId << workerIdShift) | sequence;
  

  }

  protected long tilNextMillis(long lastTimestamp) {
  long timestamp = timeGen();
  while (timestamp <= lastTimestamp) {
  timestamp = timeGen();
  }
  return timestamp;
  }

  protected long timeGen() {
  return System.currentTimeMillis();
  }
  }
  [/code]

Answer 1

是的,需要修改参数或配置才能达到产生的ID才会不重复