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  Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design. Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing? In this article, let's explore why Redis has a single-threaded architecture and still maintains its spe...

   REDIS,SINGLE-THREADED,MULTI-THREADING     2023-02-28 05:16:22

  JavaScript as a First Language

At Khan Academy we've been investigating teaching Computer Science to students in some new and interesting ways. The most interesting aspect of which is that we're likely going to be teaching them JavaScript as their first language. We're in a very unique position as we're primarily aiming to teach students who've been through our previous math and science-centric curriculum. Because of this we can create some rather compelling exercises and projects that never would've been feasible other...

   JavaScript,Learning,First language,Inheritence,Prototype     2011-12-23 07:53:45

  SQL Injection through HTTP Headers

During vulnerability assessment or penetration testing, identifying the input vectors of the target application is a primordial step. Sometimes, when dealing with Web application testing, verification routines related to SQL injection flaws discovery are restricted to the GET and POST variables as the unique inputs vectors ever. What about other HTTP header parameters? Aren’t they potential input vectors for SQL injection attacks? How can one test all these HTTP parameters and whic...

   Code security,SQL injection,HTTP header     2012-04-05 11:42:04

  How to play with cross domain request

What is cross domain request In simple, cross domain request is to request resource from other domain in one domain. Note, the "other domain" doesn't just mean domain name only, it includes much more. If the protocol, domain name, port is not the same, two domains will be considered different.  Below example describes what is considered as different domain. http://www.a.com/a.jshttp://www.a.com/b.js               # Same domainhttp://www.a.com/lab/a.js &nb...

   FRONT END,JSONP,CROSS DOMAIN,CROSS ORIGIN,CORS,DOCUMENT.DOMAIN,WINDOW.NAME     2016-11-06 00:48:54

  Simple Animation in the HTML5 Canvas Element

HTML5 is generating all kinds of buzz these days. Some of the buzz is about HTML5 being a replacement for Adobe’s Flash. I don’t think it’s there yet but it’s certainly on the way to changing the way content is presented on the web. This is a description of a very simple animation in an HTML5 canvas element. It is coded for readability and not for optimized operation. We’ll add a canvas element to a web page and then use javascript to draw on it. We will...

   HTML5,Canvas,Animation,Sample code     2011-07-01 10:20:08

  About browser event

First look at following codes: var $ = KISSY.all; $(‘a’).on(‘click’,function(e){ doSomeThing();//This function seems very famous e.halt(); }); The above codes seem complete the work we want them. The browser will not redirect us to the link in href, but is there some issue with the codes above? Before explaining what's wrong with the above codes, we first need to understand some concepts. Browser default behavior When we click a link, the browser will redirect us to anoth...

   JavaScript event,Event bubbling,event capturing     2012-11-15 11:15:41

  CSS and HTML5 responsive images

With the popularity of Retina screen, the requirement of the images in the webpages is higher. How to make sure the image still clear while enlarging twice on retina screen? This brings much trouble to web developers, the good news is CSS3 and HTML5 is trying to change this, we can use response image. What is responsive image? It means user agent loads different images according to different resolutions of output devices, it will not waste bandwidth as well. In addition, it can load respective ...

   CSS3, HTML5,image-set,responsive image     2013-03-10 03:30:07

  Google Dart? Don’t bet against JavaScript

Procotols, programming languages and operating systems all compete in a constantly evolving software ecosystem. Out of that ecosystem only a few technologies truly have staying power and survive over the long term. An example? How about Ethernet? It’s been a survivor over the last thirty years despite existing in a constantly changing landscape that’s been populated with many worthy competitors. Ethernetâ€â„...

   Google Dart,JavaScript,Comparison,Future     2011-12-06 09:49:39

  Best practices of front end optimization

1. Use DocumentFragment or innerHTML to replace complex elements insertion DOM operation on browser is expensive. Although browser performance is improved much, multiple DOM elements insertion is still expensive and will affect the page load speed. Assume we have an ul element on our page, we now want to retrieve a JSON list using AJAX and then update the ul using JavaScript. Usually we may write it as : var list = document.querySelector('ul'); ajaxResult.items.forEach(function(item) { // ...

   JavaScript,Front end,Optimization,Tips     2013-07-06 11:26:27

  Please Steal These webOS Features

When Apple introduced the first iPad in 2010, I bought one immediately. I didn’t know what I’d use it for, but I was sure that I would find some use for it. I never did. I played around with it, wrote some code for it, but eventually stopped using it. I would pick it up from time to time to read something or watch a YouTube movie, but even that was a rare occurrence. I have since picked up an iPad 2, and I’m using it a lot more than the first iPad, but again, I’...

   WebOS,Feature,HP,borrow     2012-02-22 05:45:49