Magnolia 5.6 reached end of life on June 25, 2020. This branch is no longer supported, see End-of-life policy.
Memcached is a high-performance, distributed memory object caching system. Memcached implementation for Magnolia CMS brings you the advantages of a distributed cache:
If you extend your web app from a magnolia-empty-webapp or any other web app extended from it (such as magnolia-bundled-webapp) you also need to exclude the default ehcache implementation:
<dependency> <groupId>info.magnolia</groupId> <artifactId>magnolia-empty-webapp</artifactId> <type>pom</type> <exclusions> <exclusion> <groupId>info.magnolia.cache</groupId> <artifactId>magnolia-cache-ehcache</artifactId> </exclusion> </exclusions> </dependency>
If you've never used memcached, look at how to install memcached server. You need at least one memcache server per cache. That means for every cache configuration under /modules/cache/config/contentCaching
, you need one entry under /modules/cache/config/cacheFactory/delegateFactories/memcached/caches
. This is at least (by default) defaultPageCache
and uuid-key-mapping
.
Magnolia Memcached implementation uses Spymemcached client which has its own configuration options that can be set in info.magnolia.cache.memcached.spy.MemcachedFactory info.magnolia.cache.memcached.spy.MemcachedConnectionFactoryBuilder 10000 true BINARY 998 -1 false -1 false 30 localhost:11211 ../defaultPageCache localhost:11212/modules/cache/config/cacheFactory/CACHE_NAME
.Node name Value
Parameter | Default value | Description / Available values |
protocolN2B | BINARY | BINARY or TEXT protocol. |
readBufSizeN2B | 10000 | Size of the read buffer. |
shouldOptimizeN2B | false | There are several elements of the design that each allow high throughput. |
useNagleAlgorithmN2B | true | Improves the efficiency of TCP/IP networks by reducing the number of packets that need to be sent over the network. |
maxReconnectDelayN2B | 30 | Set the maximum reconnect delay. |
opQueueMaxBlockTimeN2B | 1000 | Set the maximum amount of time (in milliseconds) a client is willing to wait for space to become available in an output queue. |
timeoutExceptionThresholdN2B | 998 | Set the maximum timeout exception threshold. |
opTimeoutN2B | -1 | Set the default operation timeout in milliseconds. |
failureModeN2B | Redistribute
|
|
transcoderN2B | net.spy.memcached.transcoders.SerializingTranscoder | Needs to be set as content node with class property:
|
locatorN2B | ARRAY_MOD
|
|
servers | - | Memcache server/s to use for this cache in format <domain or ip>:<port number> |
One of the advantages of the memcached implementation is the sharing of cache entries between multiple instances of Magnolia. If the cache item is processed by one of the public instances, it is sent to memcached server/s and other Magnolia instances do not need to render the content again; instead they may use the item cached in the registered memcached servers.
For the following tests, we requested content from two Magnolia instances at the same time. You can see the results on the first graph. As you can see the throughput is 2x bigger since the instances share the cache items. This of course applies only for the first requests for a content object, but that's the time after flushing of cache when the load on the server is highest.
The second graph shows performance when the items are precached. Memcached is a little slower than Ehcache in this case.
Please note that the Spymemcached client uses its own licence:
Spymemcached license
/**
* Copyright (c) 2006-2009 Dustin Sallings
* Copyright (c) 2009-2011 Couchbase, Inc.
*
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* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
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