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
可以使用包装器函数轻松地报告任何现有函数的执行时间。
包装器用于扩展现有函数，以便在现有函数执行之前和之后执行某些操作——这是一种组合逻辑的方便方法。
下面是一个使用withDurationReporting包装器的例子:
// without duration reporting
const doSomethingThatMayTakeAWhile = async (someArg: string, anotherArg: number) => {
/** your logic goes here */
}
// with duration reporting
const doSomethingThatMayTakeAWhileWithReporting = withDurationReporting(
'doSomethingThatMayTakeAWhile',
doSomethingThatMayTakeAWhile
);
// note: you can define the function with duration reporting directly, too
const doSomethingThatMayTakeAWhile = withDurationReporting(
'doSomethingThatMayTakeAWhile',
async (someArg: string, anotherArg: number) => {
/** your logic goes here */
}
)
这是包装器本身:
import { hrtime } from 'process';
const roundToHundredths = (num: number) => Math.round(num * 100) / 100; // https://stackoverflow.com/a/14968691/3068233
/**
* a wrapper which reports how long it took to execute a function, after the function completes
*/
export const withDurationReporting = <R extends any, T extends (...args: any[]) => Promise<R>>(
title: string,
logic: T,
options: {
reportingThresholdSeconds: number;
logMethod: (message: string, metadata?: Record<string, any>) => void;
} = {
reportingThresholdSeconds: 1, // report on anything that takes more than 1 second, by default
logMethod: console.log, // log with `console.log` by default
},
) => {
return (async (...args: Parameters<T>): Promise<R> => {
const startTimeInNanoseconds = hrtime.bigint();
const result = await logic(...args);
const endTimeInNanoseconds = hrtime.bigint();
const durationInNanoseconds = endTimeInNanoseconds - startTimeInNanoseconds;
const durationInSeconds = roundToHundredths(Number(durationInNanoseconds) / 1e9); // https://stackoverflow.com/a/53970656/3068233
if (durationInSeconds >= options.reportingThresholdSeconds)
options.logMethod(`${title} took ${durationInSeconds} seconds to execute`, { title, durationInSeconds });
return result;
}) as T;
};
其他回答
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;
}
可以使用包装器函数轻松地报告任何现有函数的执行时间。
包装器用于扩展现有函数，以便在现有函数执行之前和之后执行某些操作——这是一种组合逻辑的方便方法。
下面是一个使用withDurationReporting包装器的例子:
// without duration reporting
const doSomethingThatMayTakeAWhile = async (someArg: string, anotherArg: number) => {
/** your logic goes here */
}
// with duration reporting
const doSomethingThatMayTakeAWhileWithReporting = withDurationReporting(
'doSomethingThatMayTakeAWhile',
doSomethingThatMayTakeAWhile
);
// note: you can define the function with duration reporting directly, too
const doSomethingThatMayTakeAWhile = withDurationReporting(
'doSomethingThatMayTakeAWhile',
async (someArg: string, anotherArg: number) => {
/** your logic goes here */
}
)
这是包装器本身:
import { hrtime } from 'process';
const roundToHundredths = (num: number) => Math.round(num * 100) / 100; // https://stackoverflow.com/a/14968691/3068233
/**
* a wrapper which reports how long it took to execute a function, after the function completes
*/
export const withDurationReporting = <R extends any, T extends (...args: any[]) => Promise<R>>(
title: string,
logic: T,
options: {
reportingThresholdSeconds: number;
logMethod: (message: string, metadata?: Record<string, any>) => void;
} = {
reportingThresholdSeconds: 1, // report on anything that takes more than 1 second, by default
logMethod: console.log, // log with `console.log` by default
},
) => {
return (async (...args: Parameters<T>): Promise<R> => {
const startTimeInNanoseconds = hrtime.bigint();
const result = await logic(...args);
const endTimeInNanoseconds = hrtime.bigint();
const durationInNanoseconds = endTimeInNanoseconds - startTimeInNanoseconds;
const durationInSeconds = roundToHundredths(Number(durationInNanoseconds) / 1e9); // https://stackoverflow.com/a/53970656/3068233
if (durationInSeconds >= options.reportingThresholdSeconds)
options.logMethod(`${title} took ${durationInSeconds} seconds to execute`, { title, durationInSeconds });
return result;
}) as T;
};
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");
}
});
}
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。
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。
