13 August 2015

Why should you buy Evolved Caching?

If you are on the search for a full page caching solution for your Magento store you should you will probably have seen there are a wide range of solutions with more on the way seemingly all the time.  With Evolved Caching being at the higher end of the price range why should you pick it over other solutions?

Evolved Caching offers not only the best performance in the market place, but it's also a significantly more advanced solution than competing products.  In performance terms Evolved Caching is comparable to Varnish so you are likely to achieve the same time to first byte (TTFB).  If you want to use Varnish, then you can integrate directly and have both Varnish and Evolved Caching serve your cached pages.  Evolved Caching will also allow Varnish to cache many more pages than other Varnish only extension solutions - PageCache powered by Varnish for instance stops serving cached content altogether as soon as you add a product into the cart.

Evolved Caching is able to achieve the same TTFB as Varnish because of the way in which it serves cached content compared to other solutions. Most pull the cached content, then populate the cached page with dynamic data (i.e. mini cart, header links) before delivering anything to the browser.  Doing this however means you have to enter the Magento framework to generate the cached content and this is always going to be slow as every time you do this you need to run many thousands of lines of code and execute a large number of database requests.  This has a direct impact of how long it takes the server to deliver content to the browser and therefore your TTFB.

Evolved Caching is different because it delivers the cached content to the browser immediately giving an excellent TTFB and then populates the page with dynamic content after it has been delivered to the browser. It can populate the page with dynamic content in 2 ways, either via an AJAX request, or via BigPipe. It was the first solution to use AJAX, and the only solution to offer BigPipe as an option.

Whichever method you pick you are going to have the cached page content delivered to the browser quicker and therefore achieve a better TTFB.  To give you an idea of how much quicker, looking at some of the demo's for other solutions you might see the server taking something like around 30% of the time to generate HTML for each page (say 600ms without caching, 200ms with).  If you have a look at our benchmarks you will see you are looking at less than 0.5% of the time to generate HTML for each page.

So performance and TTFB is one reason to buy Evolved Caching over other solutions, but the benefits cover much more than just performance.  Evolved Caching has a totally different approach to keeping the cache up to date. Many other solutions rely on a cache purge and crawl cycle to refresh the cache - so this means that the entire cache is cleared and rebuilt on probably a daily, or more regular interval.  When making updates to your sites content you may not see those changes reflected until this cache purge and crawl cycle has been completed.  Evolved Caching is totally different in it's approach as the aim right from the start has been to make it a very much a hands off solution that just works while keeping your cache always primed and up to date. So just the relevant cached pages are rebuilt for instance when saving a product, category or CMS page. It also caters for caching scenarios that other solutions don't like rebuilding the cache for time limited design changes which are store wide, or just apply to a product, category or CMS page. The same is true for other time limited features such as product special prices.

Basically once a cached page has been created, there should never be a reason to have to delete it, and it should always be kept up to date automatically. Having said that, should you find for whatever reason you do need to clear your full page cache Evolved Caching does include functionality to crawl your site to create a good basic cache as a starting point (product, category and CMS pages are created). It also allows you to regenerate your entire cache should you, for instance, want to make a site wide design change that affects every page, i.e. in the header or footer.

Another reason to favour Evolved Caching over other solutions is the options it gives you in how you want to store your cached content.  You can store to files, APC, Memcached or Redis with memory based cache storage being faster on average than files.  Although some solutions offer different caching backends, many don't and only cache to files.

Evolved Caching was also developed to make it easy to configure for your install.  Other solutions require some development knowledge to holepunch any but standard blocks from caching - so you need to create an XML configuration file defining extra blocks to exclude.  Evolved Caching instead provides a frontend URL helper argument, ?shownames.  Append this to any frontend URL and the block names will be displayed, just add any of these names into the extension config in admin and that's it - no development knowledge required. You can equally add in pages by URL to be excluded from caching from admin, i.e. cart, checkout, customer login area etc.

These things are really just touching the surface of what the extension can do compared to competing, you can read a lot more in our documentation.

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