18.2. Cache Store Configuration Details (Library Mode)

The following lists contain details about the configuration elements and parameters for cache store elements in JBoss Data Grid's Library mode:
The namedCache Element

  • Add the name value to the name parameter to set the name of the cache store.
The persistence Element

  • The passivation parameter affects the way in which Red Hat JBoss Data Grid interacts with stores. When an object is evicted from in-memory cache, passivation writes it to a secondary data store, such as a system or a database. Valid values for this parameter are true and false but passivation is set to false by default.
The singleFile Element

  • The shared parameter indicates that the cache store is shared by different cache instances. For example, where all instances in a cluster use the same JDBC settings to talk to the same remote, shared database. shared is false by default. When set to true, it prevents duplicate data being written to the cache store by different cache instances. For the LevelDB cache stores, this parameter must be excluded from the configuration, or set to false because sharing this cache store is not supported.
  • The preload parameter is set to false by default. When set to true the data stored in the cache store is preloaded into the memory when the cache starts. This allows data in the cache store to be available immediately after startup and avoids cache operations delays as a result of loading data lazily. Preloaded data is only stored locally on the node, and there is no replication or distribution of the preloaded data. Red Hat JBoss Data Grid will only preload up to the maximum configured number of entries in eviction.
  • The fetchPersistentState parameter determines whether or not to fetch the persistent state of a cache and apply it to the local cache store when joining the cluster. If the cache store is shared the fetch persistent state is ignored, as caches access the same cache store. A configuration exception will be thrown when starting the cache service if more than one cache store has this property set to true. The fetchPersistentState property is false by default.
  • The ignoreModifications parameter determines whether modification methods are applied to the specific cache store. This allows write operations to be applied to the local file cache store, but not the shared cache store. In some cases, transient application data should only reside in a file-based cache store on the same server as the in-memory cache. For example, this would apply with a further JDBC based cache store used by all servers in the network. ignoreModifications is false by default.
  • The maxEntries parameter provides maximum number of entries allowed. The default value is -1 for unlimited entries.
  • The maxKeysInMemory parameter is used to speed up data lookup. The single file store keeps an index of keys and their positions in the file, restricting the size of the index using the maxKeysInMemory parameter. The default value for this parameter is -1.
  • The purgeOnStartup parameter controls whether cache store is purged when it starts up.
  • The location configuration element sets a location on disk where the store can write.
The async Element

The async element contains parameters that configure various aspects of the cache store.

  • The enabled parameter determines whether the file store is asynchronous.
  • The threadPoolSize parameter specifies the number of threads that concurrently apply modifications to the store. The default value for this parameter is 1.
  • The flushLockTimeout parameter specifies the time to acquire the lock which guards the state to be flushed to the cache store periodically. The default value for this parameter is 1.
  • The modificationQueueSize parameter specifies the size of the modification queue for the asynchronous store. If updates are made at a rate that is faster than the underlying cache store can process this queue, then the asynchronous store behaves like a synchronous store for that period, blocking until the queue can accept more elements. The default value for this parameter is 1024 elements.
  • The shutdownTimeout parameter specifies maximum amount of time that can be taken to stop the cache store. Default value for this parameter is 25 seconds.
The singleton Element

The singleton element enables modifications to be stored by only one node in the cluster. This node is called the coordinator. The coordinator pushes the caches in-memory states to disk. The shared element cannot be defined with singleton enabled at the same time.

  • The enabled attribute determines whether this feature is enabled. Valid values for this parameter are true and false. The enabled attribute is set to false by default.
  • The pushStateWhenCoordinator parameter is set to true by default. If true, this property causes a node that has become the coordinator to transfer in-memory state to the underlying cache store. This parameter is useful where the coordinator has crashed and a new coordinator is elected.
  • When pushStateWhenCoordinator is set to true, the pushStateTimeout parameter sets the maximum number of milliseconds that the process pushing the in-memory state to the underlying cache loader can take. The default time for this parameter is 10 seconds.
The remoteStore Element

  • The remoteCacheName attribute specifies the name of the remote cache to which it intends to connect in the remote Infinispan cluster. The default cache will be used if the remote cache name is unspecified.
  • The fetchPersistentState attribute, when set to true, ensures that the persistent state is fetched when the remote cache joins the cluster. If multiple cache stores are chained, only one cache store can have this property set to true . The default for this value is false.
  • The shared attribute is set to true when multiple cache instances share a cache store, which prevents multiple cache instances writing the same modification individually. The default for this attribute is false.
  • The preload attribute ensures that the cache store data is pre-loaded into memory and is immediately accessible after starting up. The disadvantage of setting this to true is that the start up time increases. The default value for this attribute is false.
  • The ignoreModifications attribute prevents cache modification operations such as put, remove, clear, store, etc. from affecting the cache store. As a result, the cache store can become out of sync with the cache. The default value for this attribute is false.
  • The purgeOnStartup attribute ensures that the cache store is purged during the start up process. The default value for this attribute is false.
  • The tcpNoDelay attribute triggers the TCP NODELAY stack. The default value for this attribute is true.
  • The pingOnStartup attribute sends a ping request to a back end server to fetch the cluster topology. The default value for this attribute is true.
  • The keySizeEstimate attribute provides an estimation of the key size. The default value for this attribute is 64.
  • The valueSizeEstimate attribute specifies the size of the byte buffers when serializing and deserializing values. The default value for this attribute is 512.
  • The forceReturnValues attribute sets whether FORCE_RETURN_VALUE is enabled for all calls. The default value for this attribute is false.
The servers and server Elements

Create a servers element within the remoteStore element to set up the server information for multiple servers. Add a server element within the general servers element to add the information for a single server.

  • The host attribute configures the host address.
  • The port attribute configures the port used by the Remote Cache Store.
The connectionPool Element

  • The maxActive attribute indicates the maximum number of active connections for each server at a time. The default value for this attribute is -1 which indicates an infinite number of active connections.
  • The maxIdle attribute indicates the maximum number of idle connections for each server at a time. The default value for this attribute is -1 which indicates an infinite number of idle connections.
  • The maxTotal attribute indicates the maximum number of persistent connections within the combined set of servers. The default setting for this attribute is -1 which indicates an infinite number of connections.
  • The connectionUrl parameter specifies the JDBC driver-specific connection URL.
  • The username parameter contains the username used to connect via the connectionUrl.
  • The driverClass parameter specifies the class name of the driver used to connect to the database.
The leveldbStore Element

  • The location parameter specifies the location to store the primary cache store. The directory is automatically created if it does not exist.
  • The expiredLocation parameter specifies the location for expired data using. The directory stores expired data before it is purged. The directory is automatically created if it does not exist.
  • The shared parameter specifies whether the cache store is shared. The only supported value for this parameter in the LevelDB cache store is false.
  • The preload parameter specifies whether the cache store will be pre-loaded. Valid values are true and false.
The jpaStore Element

  • The persistenceUnitName attribute specifies the name of the JPA cache store.
  • The entityClassName attribute specifies the fully qualified class name of the JPA entity used to store the cache entry value.
  • The batchSize (optional) attribute specifies the batch size for cache store streaming. The default value for this attribute is 100.
  • The storeMetadata (optional) attribute specifies whether the cache store keeps the metadata (for example expiration and versioning information) with the entries. The default value for this attribute is true.
The binaryKeyedJdbcStore, stringKeyedJdbcStore, and mixedKeyedJdbcStore Elements

  • The fetchPersistentState parameter determines whether the persistent state is fetched when joining a cluster. Set this to true if using a replication and invalidation in a clustered environment. Additionally, if multiple cache stores are chained, only one cache store can have this property enabled. If a shared cache store is used, the cache does not allow a persistent state transfer despite this property being set to true. The fetchPersistentState parameter is false by default.
  • The ignoreModifications parameter determines whether operations that modify the cache (e.g. put, remove, clear, store, etc.) do not affect the cache store. As a result, the cache store can become out of sync with the cache.
  • The purgeOnStartup parameter specifies whether the cache store is purged when initially started.
  • The key2StringMapper parameter specifies the class name of the Key2StringMapper used to map keys to strings for the database tables.
The binaryKeyedTable and stringKeyedTable Elements

  • The dropOnExit parameter specifies whether the database tables are dropped upon shutdown.
  • The createOnStart parameter specifies whether the database tables are created by the store on startup.
  • The prefix parameter defines the string prepended to name of the target cache when composing the name of the cache bucket table.
The idColumn, dataColumn, and timestampColumn Elements

  • The name parameter specifies the name of the column used.
  • The type parameter specifies the type of the column used.
The store Element

  • The class parameter specifies the class name of the cache store implementation.
  • The preload parameter specifies whether to load entries into the cache during start up. Valid values for this parameter are true and false.
  • The shared parameter specifies whether the cache store is shared. This is used when multiple cache instances share a cache store. Valid values for this parameter are true and false.
The property Element

  • The name parameter specifies the name of the property.
  • The value parameter specifies the value of the property.