counter

I was considering to use Amazon DynamoDB in my application, and I have a question regarding its atomic counters reliability. I'm building a distributed application that needs to concurrently , and consistently , increment/decrement a counter stored in a Dynamo's attribute. I was wondering how reliable the Dynamo's atomic counter is in an heavy concurrent environment, where the concurrency level is extremely high (let's say, for example, an average rate of 20k concurrent hits - to get the idea, that would be almost 52 billions increments/decrements per month). The counter should be super

Assuming I have the following markup: <button id="dec">-</button> <output id="out">0</output> <button id="inc">+</button> <button id="res">RESET</button> And the following Rx.js script: var total = 0 Rx.Observable.merge( // decrement Rx.Observable.fromEvent($('#dec'), 'click') .map(function() { return -1 }), // increment Rx.Observable.fromEvent($('#inc'), 'click') .map(function() { return +1 }), // reset Rx.Observable.fromEvent($('#res'), 'click') .map(function() { return -total }) ) // merge .forEach(function(delta) { total += delta $('#out').text(total) }) Everything works as expected.

Counter目的是用来跟踪值出现的次数。它是一个无序的容器类型，以字典的键值对形式存储，其中元素作为key，其计数作为value。计数值可以是任意的Interger（包括0和负数）。Counter类和其他语言的bags或multisets很相似。 创建 下面的代码说明了Counter类创建的四种方法： Counter类的创建 来源： https://www.cnblogs.com/lz1996/p/11568051.html