LATEST VERSION: 9.2.0 - CHANGELOG
Pivotal GemFire® v9.2

Changing the Default GemFire Configuration in the Tomcat Module

By default, the Tomcat module will run GemFire automatically with pre-configured settings. You can change these GemFire settings.

Here are the default settings:

  • Locators are used for member discovery.
  • The region name is set to gemfire_modules_sessions.
  • The cache region is replicated for peer-to-peer configurations and partitioned (with redundancy turned on) for client/server configurations.
  • GemFire clients have local caching turned on and when the local cache needs to evict data, it will evict least-recently-used (LRU) data first.

Note: On the application server side, the default inactive interval for session expiration is set to 30 minutes. To change this value, refer to Session Expiration.

Changing GemFire Distributed System Properties

GemFire system properties must be set by adding properties to Tomcat’s server.xml file. When setting properties, use the following syntax:

<Listener 
  className="org.apache.geode.modules.session.catalina.xxxLifecycleListener"
  name="value" 
  name="value" 
  ...
/> 

If the xxxLifecycleListener is a PeerToPeerCacheLifecycleListener, then a minimal addition to the server.xml file is

<Listener 
  className="org.apache.geode.modules.session.catalina.
     PeerToPeerCacheLifecycleListener"
  cache-xml-file="cache-peer.xml" 
  locators="localhost[10334]" 
 /> 

The list of configurable Tomcat’s server.xml system properties include any of the properties that can be specified in GemFire’s gemfire.properties file. The following list contains some of the properties that can be configured.

Parameter Description Default
cache-xml-file name of the cache configuration file cache-peer.xml for peer-to-peer, cache-client.xml for client/server
locators (only for peer-to-peer topology) (required) list of locators (host[port]) used by GemFire members; if a single locator listens on its default port, then set this value to "localhost[10334]" empty string
log-file name of the GemFire log file gemfire_modules.log
statistic-archive-file name of the GemFire statistics file gemfire_modules.gfs
statistic-sampling-enabled whether GemFire statistics sampling is enabled false

For more information on these properties, along with the full list of properties, see the Reference.

In addition to the standard GemFire system properties, the following cache-specific properties can also be configured with the LifecycleListener.

Parameter Description Default
criticalHeapPercentage percentage of heap at which updates to the cache are refused 0 (disabled)
evictionHeapPercentage percentage of heap at which session eviction begins 80.0
rebalance whether a rebalance of the cache should be done when the application server instance is started false

Although these properties are not part of the standard GemFire system properties, they apply to the entire JVM instance and are therefore also handled by the LifecycleListener. For more information about managing the heap, refer to Managing Heap and Off-heap Memory.

Changing Cache Configuration Properties

To edit GemFire cache properties such as the name and the characteristics of the cache region, you add these properties to Tomcat’s context.xml file. When adding properties, unless otherwise specified, use the following syntax:

<Manager 
  className="org.apache.geode.modules.session.catalina.Tomcat7DeltaSessionManager"
  name="value" 
  name="value" 
  ...
/> 

In the preceding code snippet, name is the property name and value is the property value. For example:

<Manager className="org.apache.geode.modules.session.catalina.
      Tomcat7DeltaSessionManager" 
  regionAttributesId="PARTITION_REDUNDANT" 
  regionName="my_region" 
/> 

This example creates a partitioned region by the name of “my_region”.

The following parameters are the cache configuration parameters that can be added to Tomcat’s context.xml file.

CommitSessionValve
Whether to wait until the end of the HTTP request to save all session attribute changes to the GemFire cache; if the configuration line is present in the application’s context.xml file, then only one put will be performed into the cache for the session per HTTP request. If the configuration line is not included, then the session is saved each time the setAttribute or removeAttribute method is invoked. As a consequence, multiple puts are performed into the cache during a single session. This configuration setting is recommended for any applications that modify the session frequently during a single HTTP request.

Default: Set

To disable this configuration, remove or comment out the following line from Tomcat’s context.xml file.

<Valve className="org.apache.geode.modules.session.catalina.CommitSessionValve"/>

enableDebugListener
Whether to enable a debug listener in the session region; if this parameter is set to true, info-level messages are logged to the GemFire log when sessions are created, updated, invalidated or expired.

Default: false

The GemFire API equivalent to setting this parameter:

// Create factory
AttributesFactory factory = ...; <or> RegionFactory factory = ...;
// Add cache listener
factory.addCacheListener(new DebugCacheListener());

enableLocalCache
Whether a local cache is enabled. If this parameter is set to true, the app server load balancer should be configured for sticky session mode.

Default: false for peer-to-peer, true for client/server

The GemFire API equivalent to setting this parameter:

// For peer-to-peer members: 
Cache.createRegionFactory(REPLICATE_PROXY); 
// For client members: 
ClientCache.createClientRegionFactory(CACHING_PROXY_HEAP_LRU);

regionAttributesId
Specifies the region shortcut. For more information see Region Shortcuts and Custom Named Region Attributes; when using a partitioned region attribute, it is recommended that you use PARTITION_REDUNDANT (rather than PARTITION) to ensure that the failure of a server does not result in lost session data.

Default: REPLICATE for peer-to-peer, PARTITION_REDUNDANT for client/server

The GemFire API equivalent to setting this parameter:

// Creates a region factory for the specified region shortcut 
Cache.createRegionFactory(regionAttributesId); 

regionName
Name of the region.

Default: gemfire_modules_sessions

The GemFire API equivalent to setting this parameter:

// Creates a region with the specified name 
RegionFactory.create(regionName);