GuavaCacheProvider¶

GuavaCacheProvider provides local in-memory caching by using a Guava Cache for storing the various GWC Tiles locally on the machine. For configuring a GuavaCacheProvider the user must create a new bean in the Application Context file (like geowebcache-core-context.xml) and then add a reference to a CacheConfiguration instance.

Here is an example of configuration:

<bean id="cacheConfiguration" class="org.geowebcache.storage.blobstore.memory.CacheConfiguration">
  <property name="hardMemoryLimit" value="64"/> <!-- 64 Mb -->
      <property name="policy" value="EXPIRE_AFTER_ACCESS"/> <!-- Cache Eviction Policy is EXPIRE_AFTER_ACCESS. Other values are EXPIRE_AFTER_WRITE, NULL(LRU eviction based on cache size) -->
      <property name="evitionTime" value="240"/> <!-- Eviction time is 240 seconds -->
      <property name="concurrencyLevel" value="4"/> <!-- Concurrency Level of the cache is 4 -->
</bean>

<bean id="guavaCacheProvider" class="org.geowebcache.storage.blobstore.memory.guava.GuavaCacheProvider">
  <property name="configuration" ref="cacheConfiguration"/> <!-- Setting of the configuration -->
</bean>

HazelcastCacheProvider¶

HazelcastCacheProvider is useful for implementing distributed in memory caching for clustering. It internally uses Hazelcast for handling distributed caching. The HazelcastCacheProvider configuration requires another object called HazelcastLoader. This object accepts an Hazelcast instance or loads a file called hazelcast.xml from a proper directory defined by the property “hazelcast.config.dir”. If none of them is present, the CacheProvider object cannot be used.

The user must follow these rules for configuring the Hazelcast instance:

1. The Hazelcast configuration requires a Map object with name CacheProviderMap
2. Map eviction policy must be LRU or LFU
3. Map configuration must have a fixed size defined in Mb
4. Map configuration must have USED_HEAP_SIZE as MaxSizePolicy

Here the user can find both examples:

• From hazelcast.xml:

  <hazelcast xsi:schemaLocation="http://www.hazelcast.com/schema/config hazelcast-config-2.3.xsd"
                     xmlns="http://www.hazelcast.com/schema/config"
                     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <group>
          <name>cacheCluster</name>
          <password>geoserverCache</password>
    </group>
  
    <network>
          <!--
                  Typical usage: multicast enabled with port auto-increment enabled
                  or tcp-ip enabled with port auto-increment disabled. Note that you
                  must choose between multicast and tcp-ip. Another option could be
                  aws, but will not be described here.
  
          -->
          <port auto-increment="false">5701</port>
                  <join>
                           <multicast enabled="false">
                                  <multicast-group>224.2.2.3</multicast-group>
                                  <multicast-port>54327</multicast-port>
                          </multicast>
                          <tcp-ip enabled="true">
                                  <interface>192.168.1.32</interface>
                                  <interface>192.168.1.110</interface>
                          </tcp-ip>
                  </join>
    </network>
    <map name="CacheProviderMap">
                  <eviction-policy>LRU</eviction-policy>
                  <max-size policy="USED_HEAP_SIZE">16</max-size>
    </map>
  
  </hazelcast>
  

  And the related application context will be:

  <bean id="HazelCastLoader1"
          class="org.geowebcache.storage.blobstore.memory.distributed.HazelcastLoader">
  </bean>
  
  <bean id="HazelCastCacheProvider1"
          class="org.geowebcache.storage.blobstore.memory.distributed.HazelcastCacheProvider">
          <constructor-arg ref="HazelCastLoader1" />
  </bean>
  

  Note

  Remember that in this case the user must define the hazelcast.config.dir property when starting the application.

• From application context (See Hazelcast documentation for more info):

  <hz:hazelcast id="instance1">
          <hz:config>
                  <hz:group name="dev" password="password" />
                  <hz:network port="5701" port-auto-increment="true">
                          <hz:join>
                                  <hz:multicast enabled="true" multicast-group="224.2.2.3"
                                          multicast-port="54327" />
                          <hz:tcp-ip enabled="false">
                            <hz:members>10.10.1.2, 10.10.1.3</hz:members>
                          </hz:tcp-ip>
                          </hz:join>
                  </hz:network>
                  <hz:map name="CacheProviderMap" max-size="16" eviction-policy="LRU"
                          max-size-policy="USED_HEAP_SIZE" />
          </hz:config>
  </hz:hazelcast>
  
  <bean id="HazelCastLoader1"
          class="org.geowebcache.storage.blobstore.memory.distributed.HazelcastLoader">
          <property name="instance" ref="instance1" />
  </bean>
  
  <bean id="HazelCastCacheProvider1"
          class="org.geowebcache.storage.blobstore.memory.distributed.HazelcastCacheProvider">
          <constructor-arg ref="HazelCastLoader1" />
  </bean>
  

Optional configuration parameters¶

In this section are described other available configuration parameters to configure:

• Cache expiration time:

  <map name="CacheProviderMap">
  ...
  
          <time-to-live-seconds>0</time-to-live-seconds>
          <max-idle-seconds>0</max-idle-seconds>
  
  </map>
  

  Where time-to-live-seconds indicates how many seconds an entry can stay in cache and max-idle-seconds indicates how many seconds an entry may be not accessed before being evicted.

• Near Cache.

  <map name="CacheProviderMap">
  ...
  <near-cache>
    <!--
          Same configuration parameters of the Hazelcast Map. Note that size indicates the maximum number of
          entries in the near cache. A value of Integer.MAX_VALUE indicates no limit on the maximum
          size.
    -->
    <max-size>5000</max-size>
    <time-to-live-seconds>0</time-to-live-seconds>
    <max-idle-seconds>60</max-idle-seconds>
    <eviction-policy>LRU</eviction-policy>
  
    <!--
          Indicates if a cached entry can be evicted if the same value is modified in the Hazelcast Map. Default is true.
    -->
    <invalidate-on-change>true</invalidate-on-change>
  
    <!--
          Indicates if local entries must be cached. Default is false.
    -->
    <cache-local-entries>false</cache-local-entries>
  </near-cache>
  
  </map>
  

  Near Cache is a local cache for each cluster instance which is used for caching entries in the other cluster instances. This behaviour avoids to request those entries each time by executing a remote call. This feature could be helpful in order to improve Hazelcast Cache performances.

  Note

  A value of max-size bigger or equal to Integer.MAX_VALUE cannot be used in order to avoid an uncontrollable growth of the cache size.