Like Index Management in Magento, the Cache Management system in Magento is a useful tool to optimise site speed and performance. While cache has become such a necessary part of internet browsing, it is probably without a doubt one of the least understood parts of Magento.
So what exactly is cache? Cache is the temporary storage of web documents (such as HTML, images, etc) so as to increase speed of subsequent requests. Once a user visits a webpage, Magento will cache the page, making every subsequent requests and loading of that page quicker.
Cache options in Magento are found via the cache management screen, (via System > Cache Management) in the admin system. It is from this screen that cache is cleared/flushed. Pressing the Flush Magento Cache will flush enabled cache types here that are set to enabled.
Magento has the following cache types:
- Configuration (non-layout XML files)
- Blocks HTML output (Page blocks, such as footers)
- Collections Data
- EAV types and attributes
- Web Services Configuration
How to Flush Cache
- Navigate to System > Cache Management to arrive at the Cache Storage Management screen.
- On the Cache Management screen, you can view all the types and status of caches used in Magento. Available statuses include: Enabled, Invalidated and Disabled. Cache that requires a refresh will be marked with the status of Invalidated (will appear in Yellow).
How to Flush all Cache
- Using the Select All to the top left of the grid, select all and then click 'Flush Magento Cache' to clear all cache. Any caches that were previously marked as Invalidated should now appear in green with the status of Enabled.
How to Flush Specific Cache
- Using the checkbox(s) beside each of the cache types, select which cache you would like to refresh and once happy with selection, click the 'Flush Magento Cache' button.
Note: Underneath the main cache grid on the Cache Storage Management screen, you may have noticed Additional Cache Management buttons. These additional cache types are as follows:
- Flush Catalog Images Cache - Removes all automatically resized and watermarked catalog images that are stored at: media/catalog/products/cache.
- Flush Swatch Images Cache - Removes pregenerated swatch image files
- Re-build Visual Merchandiser categories - Rebuilds the visual merchandiser categories.
Enterprise Edition Only
Full page cache (FPC) can help reduce server load and improve response times by allowing for fully-generated pages to be read directly from the cache. This will also mean that even with subsequent page loads, the load on the server will remain as low as possible as well as increasing site speed. It can be very beneficial in the instance that your store / website regularly experiences bouts of high traffic - and might even be necessary to keeping your site optimised.