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SEARCH KEYWORD -- HTTP Cache



  Cache Reheating - Not to be Ignored


An important aspect to keep in mind with databases is the cost of cache reheating after a server restart. Consider the following diagram which shows several cache servers (e.g., memcached) in front of a database server.This sort of setup is common and can work quite well when appropriate; it removes read load from the database and allows more RAM to be utilized for scaling (when the database doesn’t scale horizontally). But what happens if all the cache servers restart at the same time, say, o...

   Database,Cost,Cache reheating,Advice     2011-09-21 09:47:29


  How key-based cache expiration works


There are only two hard things in Computer Science: cache invalidation and naming things — Phil Karlton Doing cache invalidation by hand is an incredibly frustrating and error-prone process. You’re very likely to forget a spot and let stale data get served. That’s enough to turn most people off russian-doll caching structures, like the one we’re using for Basecamp Next. Thankfully there’s a better way. A much better way. It’s called key-based cache expiration and it works lik...

   Cache,Expiration,Key-base cache,Work     2012-02-20 05:32:40


  Content based HTTP Cache


Browsers may cache the webpages we visited, when user types a URL on the address bar, the browser may cache the webpage returned from server while displaying it. If there is no update on the webpage, then next time when the browser requests the same page, it will not download the page again, instead it will load the cached page. If the website explicitly specify that the page is updated, then the browser will download the page again from the server. What's HTTP Cache? You may be familiar with th...

   HTTP Cache,Web crawler     2013-05-24 05:12:59


  Meta tag in HTML header


In server response, we can use response.setHeader() to set the meta information in header of a HTML page. The usage is response.setHeader(name,context); meta is used to simulate the response header of HTTP protocol in HTML page. It should be put between the <head> and </head> tag. 1. <meta name="Generator" content="" > <!--This is to specify the tool which generates this page such as Microsoft FrontPage 4.0 etc --> 2. <meta name="keywords" content=""> <!-- To tel...

   HTTP,meta,HTML,head     2013-05-22 11:34:08


  Differences among Enter,F5 and Ctrl+F5 in webpage refresh


When we press Enter, F5 or Ctrl+F5 to refresh a webpage, is there any difference among them? Actually it's yes, we can find the difference from the request header and response header information. There are two cases about pressing Enter in the address bar. First if the page requested is cached and not expired in the browser, we can find the header information sent by the browser is : Host 192.168.3.174:8080 User-Agent Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0 Accept ...

   Refresh,F5,Ctrl+F5     2013-06-13 22:03:35


  Diving Deeper into HTML5 Offline Browsing


Recently, I published an article on one of the new features in HTML 5 called Offline Browsing  in HTML5 with ApplicationCache.The response to that article was good, and I was asked to expand on some further points including:how to decide on what files to cachethe implications of caching those filesdebugging the ApplicationCacheSo, that’s where this article will start: where the last one finished.  If you haven’t, you should probably read the previous article before this one.Let’s...

   HTML5,Offline browsing,New breakthrough,Feature     2011-12-20 08:46:06


  Buffcacher


What should a ‘cache’ be? It means a lot of things, but to my mind the default programming type should be: “keep around expensive-to-generate bits of read-only data in case we need them again, or until the computer really needs that RAM for something else” I was writing a custom video editing program in Python (interesting choice of language for that problem) and I wanted to cache decoded frames; but I just wasn’t happy with the memory management of explicit caches.  It me...

   Buffer,Cache,Web browser,Memory,RAM     2012-02-24 05:10:10


  Will PHP __autoload() function really affect performance?


IntroductionRegarding to PHP performance, the most frequently discussed is the __autoload() function. Many people say that this function will affect the performance very much, some other people say that opcode will affect __autoload() as well. So we will have some tests on these two.EnvironmentPHP 5.3.9 -- Launch under fastcgi modeNginx 1.1.12eAccelerator 0.9.6.1ScreenshotsLaunch pageeAccelerator(In php.ini) configurationFile structure(each Test file has over 6000 lines of code)Testing With e...

   PHP,__autoload(),opcode,performance     2012-05-09 11:25:26


  Reducing Code Nesting


"This guy’s code sucks!" It’s something we’ve all said or thought when we run into code we don’t like. Sometimes it’s because it’s buggy, sometimes it’s because it conforms to a style we don’t like, and sometimes it’s because it just feels wrong. Recently I found myself thinking this, and automatically jumping to the conclusion that the developer who wrote it was a novice. The code had a distinct property that I dislike: lots of nesting. But the more I think about it, the ...

   Code nesting,Readability,Maintainability,Reduction     2012-01-02 08:13:46


  Load and execute JavaScript


When we load and execute JavaScript in a webpage, there are many points we need to care about because of its design and feature. There are two features about JavaScript execution in a browser: 1). The JavaScript codes will be executed immediately once loaded;2). When JavaScript codes are being executed, they will block the following contents (including page rendering and other resources downloading). So if there are multiple js files to be loaded, these codes will be executed sequentially. Since...

   JavaScript,async,defer,load,execute     2013-06-07 04:53:46