Improving Performance - Client-side caching
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Client-side caching is a feature that stores frequently used information on the client's machine. It provides performance enhancements on the client side by allowing the client to quickly access a file that would have normally be accessed from a server.. Client caching is especially effective when the client disconnects from the server, in that case files can still be accessed from the local cache. Client-side caching is usually defined in the client's browser settings.
Dynamic content caching maximizes performance and scalability Dynamic content caching solutions address the scaling and performance issues of Web servers directly. They work well for heavily visited sites containing many dynamic features that must be tuned to respond quickly and easily. For a growing company anticipating reaching the Web server's maximum processing power, dynamic content caching solutions will expand the Web server’s capacity more effectively than adding additional hardware to manage the load. In certain cases, server-side dynamic caching may be 20 to 100 times faster than processing the page normally.
Two factors to keep in mind when considering whether to cache dynamic pages include frequency of content changes and demand level for current content (hit count). Anticipated hit count determines the prioritization of pages to be cache. More popular pages take precedence over less frequently accessed pages. Some caching solutions provide analysis of script popularity on the site.
Full page caching
Full-page caching is the simplest and most straightforward dynamic caching mechanism. The user defines which page to cache and the server stores it in the cache disk space. In subsequent request for the page, instead of parsing the page, running the script and building the HTML page, the server will locate the existing cached page and send it to the client. The home page for a Web site is an excellent example of a popular page for full-page caching. Generally it is the first page that users see, the most frequently accessed and therefore has the greatest impact on the user experience. As mentioned, when using dynamic content caching the web server no longer creates pages for each request, but sends pre-built copies to the clients. Therefore, users do not see content changes once a page has been cached. Introducing the concept of 'lifetime' settings can solve this problem while still maintaining huge performance gains, even when set as low as two minutes. Lifetime settings permit the server to discard cached pages once their defined lifetime has expired, forcing the application server to reprocess the pages.
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