Hibernate - Memcached

A library for using Memcached as a second level distributed cache in Hibernate.

• Uses spymemcached client
• Supports entity and query caching.

Jump to

• Maven dependency
• Configuration options
• Versions

Maven dependency

To install it, you just need to add the following Maven dependency (check Versions for the right version for you):

<dependency>
    <groupId>com.github.mihaicostin</groupId>
    <artifactId>hibernate-l2-memcached</artifactId>
    <version>5.2.7.0</version>
</dependency>

https://mvnrepository.com/artifact/com.github.mihaicostin/hibernate-l2-memcached

Example config:

<property name="hibernate.cache.region.factory_class">com.mc.hibernate.memcached.MemcachedRegionFactory</property>
<property name="hibernate.memcached.operationTimeout">5000</property>
<property name="hibernate.memcached.connectionFactory">KetamaConnectionFactory</property>
<property name="hibernate.memcached.hashAlgorithm">FNV1_64_HASH</property>

If memcached authentication is required you can specify username and password:

<property name="hibernate.memcached.username">memcached-username</property>
<property name="hibernate.memcached.password">memcached-password</property>

If memcached are running on a remote server, e.g. on AWS ElastiCache, you can specify the connection URL:

<property name="hibernate.memcached.servers">cache.c3wd5k.cfg.euw1.cache.amazonaws.com:11211</property>

Configuration options

Targeting the memcached client (net.spy.memcached configurations)

Property	Default Value
hibernate.memcached.servers	localhost:11211
hibernate.memcached.operationQueueLength	(default provided by net.spy.memcached.DefaultConnectionFactory)
hibernate.memcached.readBufferSize	(default provided by net.spy.memcached.DefaultConnectionFactory)
hibernate.memcached.operationTimeout	(default provided by net.spy.memcached.DefaultConnectionFactory)
hibernate.memcached.hashAlgorithm	NATIVE_HASH
hibernate.memcached.connectionFactory	DefaultConnectionFactory
hibernate.memcached.daemonMode	false
hibernate.memcached.username	-
hibernate.memcached.password	-

Targeting the cache implementation (global or region specific)

Property	Default Value
hibernate.memcached.cacheTimeSeconds	300
hibernate.memcached.clearSupported	false
hibernate.memcached.memcacheClientFactory	com.mc.hibernate.memcached.spymemcached.SpyMemcacheClientFactory
hibernate.memcached.dogpilePrevention	false
hibernate.memcached.dogpilePrevention.expirationFactor	2
hibernate.memcached.keyStrategy	com.mc.hibernate.memcached.keystrategy.Sha1KeyStrategy

In order to specify a property for a specific region add the region name right after memcached. ex: hibernate.memcached.myregion.cacheTimeSeconds

Versions

Use the version compatible with your hibernate version (ex: Version 5.2.1.x is developed for and compatible with hibernate 5.2.1.Final)

Hibernate 5.2.x

• v 5.2.10.0
  • Add a new cache property hibernate.memcached.cacheLockTimeout (defaults to 60.000 ms)
  • Update to latest spymemcached version
  • hibernate-core dependency (as provided): 5.2.10.Final
• v 5.2.7.1
  • Fix for Issue #9
• v 5.2.7.0
  • Support Hibernate 5.2.7.Final (PR by @akhalikov )
  • Update spymemcached to 2.12.2
  • Tested with 5.2.7.Final - 5.2.10.Final
• v 5.2.1.0
  • Update spymemcached to the latest version: 2.12.1

Hibernate 5.1.x

• v 5.1.5.1
  • Fix for Issue #9
• v 5.1.5.0
  • Support for Hibernate 5.1.x (tested with 5.1.1.Final - 5.1.5.Final)

Hibernate 5.0.x

• v 5.0.1.0
  • Support for Hibernate 5.0.x

Hibernate 4.3.x

• v 4.3.11.0
  • Fix for Issue #9 (configure the cache with all available properties)
• v 1.1.0
  • Memcached client now respects the region timeout property Issue #1

    <property name="hibernate.memcached.REGION.cacheTimeSeconds">10</property>

• v 1.0.0
  • Compatible with hibernate 4.3.x

Known issues

• SecondLevelCacheStatistics won't work with this adapter since it tries to get the cache content as a Map (and that's not easily done with memcached)
• Cache region eviction won't actually evict the key, but invalidate them (see https://github.com/memcached/memcached/wiki/ProgrammingTricks#deleting-by-namespace)

Acknowledgements

• Based on the work done on Hibernate-Memcached for hibernate 3.x
  • https://github.com/raykrueger/hibernate-memcached
  • https://github.com/kcarlson/hibernate-memcached