This page summarizes the features of Magnolia cache, lists the involved modules , and explains what is available in Community and Enterprise Editions. It also proposes alternatives for some of the third-party libraries.
The need to cache content is very different in developing, staging or production environments. If your system relies heavily on cache for performance the system may be misconfigured or it suffers from too small servers.
Caching features by edition
Caching arbitrary objects
With Magnolia you can cache basically every object beyond the well known page caching, for further details see caching arbitrary objects.
Magnolia caches content on a page level by default. This means that page is the smallest unit you can cache with the standard Cache module. The Dynamic Page Caching add-on allows you to cache fragments of a page.
Web resources caching
Magnolia has a separate Digital asset management module. Assets (for example images) and asset renditions served directly from Magnolia are cached by default. Assets served from external an DAM such as Cumulus DAM connector or Amazon S3 Connector module are not cached by Magnolia.
Granular cache policy configuration
The cache policy - what should be cached and what not - is highly customizable according to your requirements.
Granular flush policy configuration
You can define flush policies - rules when the cache must be flushed. For instance, you can make flush procedure depend on changes on JCR repositories.
Ehcache is Magnolia's default third-party low level cache implementation. (For more details see below.)
Alternative third-party low level cache implementation. (For more details see below.)
Cache Browser app
The Cache Browser app runs on an author instance and allows you to delete cache items on a granular level. The app will delete cached items on all the public instances - independent of your public instances setup - be it a single instance or a complex cluster.
Personalized variant caching
Dynamic page caching
Magnolia cache uses established third-party libraries for the low level functions. Depending on your production environment, one cache implementation may fit better than another. Please contact Magnolia Services to get the the best cache strategy for your project and server setup.
Default implementation - Ehcache
Ehcache version update to 2.10
Cache module version 5.4 (bundled with Magnolia 5.4) updated Ehcache from 1.5 to 2.10.
Ehcache stores cached content to disk. On version 1.5, cached content was always kept on the disk as long as flushing was not proactively requested. Version 2.10 deletes cached items when the server is stopped. As a consequence, when you restart the server, the cache store must be rebuilt again. Since a production system is stopped rarely the loss of the persistent cache store is typically not a problem. A production server is typically stopped only when updating Magnolia or if the server crashes.
However, if you want to use a cache that will persist between restarts of Magnolia, use the Memcached implementation.
Alternative implementation - Memcached
- Sharing of cache items between multiple instances of Magnolia
- Cached items persist restart of Magnolia instance
- Memcached servers may run on any server in the network and thus won't consume your server memory.
List of involved modules