优化的点是,序列号不是每次都归0,而是归一个0到100的随机数。 //如果当前操作落在同一个ms(timestamp位相同)的话if(lastTimestamp == currentTimestamp) {//sequence++ 且 保证不溢出,下面测试可知道如果溢出了maxSequence就会变成0sequence = (sequence +1) & maxSequence;if(sequence ==0) {// overflow...
throw new UnsupportedOperationException("Timestamp bitsis exhausted. Refusing ID generate. Now: " + currentTimestamp); } return currentTimestamp; } private long tilNextMillis(long lastTimestamp) { long timestamp = timeGen(); while (timestamp <= lastTimestamp) { timestamp = timeGen(); } r...
如果你从其他的算法中迁移过来,可以取出之前的算法的max_id值, 初始的时间戳可以设置为minTS = current_timestamp - max_id>>22 + 1。这样的话,随着current_timestamp一直在增大,你新生成的最小值一定比之前的最大值大。 优点: 可以很方便的线性扩展,性能完全能够支撑大多数业务场景。 生成的ID满足上述数据库...
if (currentTimestamp - twepoch > MAX_DELTA_TIMESTAMP) { throw new UnsupportedOperationException("Timestamp bits is exhausted. Refusing ID generate. Now: " + currentTimestamp); } return currentTimestamp; } private long tilNextMillis(long lastTimestamp) { long timestamp = timeGen(); while (...
* @return */public static long getCurrentStamp() {return System.currentTimeMillis(); }public static void main(String[] args) { Set<Long> set = new HashSet<Long>();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) { ...
//时间戳需要左移位数 12+5+5=22位privatelongtimestampLeftShift=sequenceBits+workerIdBits+datacenterIdBits;//上次时间戳,初始值为负数privatelonglastTimestamp=-1L;publiclonggetWorkerId(){returnworkerId;}publiclonggetDatacenterId(){returndatacenterId;}publiclonggetTimestamp(){returnSystem.currentTimeMillis...
publiclonggetTimestamp(){returnSystem.currentTimeMillis();}publicIdWorker(longworkerId,longdatacenterId,longsequence){// 检查机房id和机器id是否超过31 不能小于0if(workerId>maxWorkerId||workerId<0){thrownewIllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0"...
{// 假设功率和光照强度之间的线性关系returnpowerOutput*50;// 简单的线性关系}functiongenerator(faker,options){constclientid=options.clientid;constcurrentTimestamp=Date.now();// 使用当前时间constcurrentDate=newDate(currentTimestamp).toISOString().split('T')[0];if(!store[clientid]){constdeviceType...
long timestamp = System.currentTimeMillis();if (timestamp <lastTimestamp) { throw new Runtime...
additionalFormatOptions提供給 COPY 命令充當機碼值組字典的其他檔案格式選項。 範例:DATE_FORMAT、TIME_FORMAT、TIMESTAMP_FORMAT。 如需詳細資訊,請參閱Snowflake 格式型別選項 (英文)。No 注意 請確定您有權執行下列命令,並存取架構INFORMATION_SCHEMA和資料表COLUMNS。