我有一段JavaScript代码,我正在使用node.js解释器执行。

for(var i = 1; i < LIMIT; i++) {
  var user = {
    id: i,
    name: "MongoUser [" + i + "]"
  };
  db.users.save(user, function(err, saved) {
    if(err || !saved) {
      console.log("Error");
    } else {
      console.log("Saved");
    }
  });
}

如何测量这些数据库插入操作所花费的时间?我可以在这段代码之后和之前计算日期值的差异,但这将是不正确的,因为代码的异步性质。


当前回答

我从AWS转到Azure时也遇到了同样的问题

对于express和aws,您已经可以使用,existing time()和timeEnd()

对于Azure,使用这个: https://github.com/manoharreddyporeddy/my-nodejs-notes/blob/master/performance_timers_helper_nodejs_azure_aws.js

这些time()和timeEnd()使用现有的hrtime()函数,提供高分辨率的实时时间。

希望这能有所帮助。

其他回答

调用console.time('label')将以毫秒为单位记录当前时间,然后调用console.timeEnd('label')将显示从该点开始的持续时间。

以毫秒为单位的时间会自动打印在标签旁边,所以你不需要单独调用console.log来打印标签:

console.time('test');
//some code
console.timeEnd('test'); //Prints something like that-> test: 11374.004ms

有关更多信息,请参阅console.time上的Mozilla开发者文档。

对于任何想要获得时间流逝值而不是控制台输出的人:

使用process.hrtime()作为@D。Deriso建议,以下是我更简单的方法:

function functionToBeMeasured() {
    var startTime = process.hrtime();
    // do some task...
    // ......
    var elapsedSeconds = parseHrtimeToSeconds(process.hrtime(startTime));
    console.log('It takes ' + elapsedSeconds + 'seconds');
}

function parseHrtimeToSeconds(hrtime) {
    var seconds = (hrtime[0] + (hrtime[1] / 1e9)).toFixed(3);
    return seconds;
}

令人惊讶的是,还没有人提到图书馆的新建:

在节点>= 8.5中可用,并且应该在现代浏览器中

https://developer.mozilla.org/en-US/docs/Web/API/Performance

https://nodejs.org/docs/latest-v8.x/api/perf_hooks.html#

节点8.5 ~ 9。x (Firefox, Chrome)

// const { performance } = require('perf_hooks'); // enable for node const delay = time => new Promise(res=>setTimeout(res,time)) async function doSomeLongRunningProcess(){ await delay(1000); } performance.mark('A'); (async ()=>{ await doSomeLongRunningProcess(); performance.mark('B'); performance.measure('A to B', 'A', 'B'); const measure = performance.getEntriesByName('A to B')[0]; // firefox appears to only show second precision. console.log(measure.duration); // apparently you should clean up... performance.clearMarks(); performance.clearMeasures(); // Prints the number of milliseconds between Mark 'A' and Mark 'B' })();

https://repl.it/@CodyGeisler/NodeJsPerformanceHooks

节点12.倍

https://nodejs.org/docs/latest-v12.x/api/perf_hooks.html

const { PerformanceObserver, performance } = require('perf_hooks');
const delay = time => new Promise(res => setTimeout(res, time))
async function doSomeLongRunningProcess() {
    await delay(1000);
}
const obs = new PerformanceObserver((items) => {
    console.log('PerformanceObserver A to B',items.getEntries()[0].duration);
      // apparently you should clean up...
      performance.clearMarks();
      // performance.clearMeasures(); // Not a function in Node.js 12
});
obs.observe({ entryTypes: ['measure'] });

performance.mark('A');

(async function main(){
    try{
        await performance.timerify(doSomeLongRunningProcess)();
        performance.mark('B');
        performance.measure('A to B', 'A', 'B');
    }catch(e){
        console.log('main() error',e);
    }
})();

我需要它是累积的,用来测量不同的东西。 构建这些函数:

function startMeasuring(key) {
  measureTimers[key] = process.hrtime();
}

function stopMeasuring(key) {
  if (!measures[key]) {
    measures[key] = 0;
  }

  let hrtime = process.hrtime(measureTimers[key]);
  measures[key] += hrtime[0] + hrtime[1] / 1e9;
  measureTimers[key] = null;
}

用法:

startMeasuring("first Promise");
startMeasuring("first and second Promises");
await new Promise((resolve) => {
  setTimeout(resolve, 1400);
});
stopMeasuring("first Promise");
stopMeasuring("first and second Promises");

startMeasuring("first and second Promises");
await new Promise((resolve) => {
  setTimeout(resolve, 600);
});
stopMeasuring("first and second Promises");

console.log("Measure Results", measures); 
/*
Measusre Results {
  setting: 0.00002375,
  'first Promise': 1.409392916,
  'first and second Promise': 2.015160376
}
*/
var start = +new Date();
var counter = 0;
for(var i = 1; i < LIMIT; i++){
    ++counter;
    db.users.save({id : i, name : "MongoUser [" + i + "]"}, function(err, saved) {
          if( err || !saved ) console.log("Error");
          else console.log("Saved");
          if (--counter === 0) 
          {
              var end = +new Date();
              console.log("all users saved in " + (end-start) + " milliseconds");
          }
    });
}