Cluster Deployment Descriptor Reference : Cluster Tab — Cache OM — Domain Objects Settings

Cluster Tab — Cache OM — Domain Objects Settings
TIBCO BusinessEvents Express  This section relates to Cache OM functionality and does not apply to TIBCO BusinessEvents Express edition.
Configure object management options at the default (that is global) level, and as needed add entries to configure overrides at the object level.
Two tables are provided, one for the settings at the default level, and one for the similar settings that can be set for individual objects.
All objects use the default level settings unless you specify differently for them at the override level.
Default Level Settings
The Domain Object Default settings apply to all objects except those for which you explicitly configure overrides, using the Domain Object Overrides section.
 
Memory Only: Objects are not persisted in the cache. They are kept in the Rete network (working memory) only.
Cache Only: Objects are persisted in the cache. They must be loaded into working memory as needed. This is the most common choice for a cache cluster.
Cache+Memory (also written as Cache Plus Memory): Objects are persisted in the cache. They are also kept current in the Rete network.
Note: Due to issues with concurrency, in clusters with multiple active inference agents, use Cache Plus Memory only for constants and objects that change infrequently.
Note  If you set the mode to Memory Only, the rest of the properties in this section are not relevant and are ignored.
See Chapter 8, Cache Modes and Project Design in TIBCO BusinessEvents Architect’s Guide to understand the effect of this setting.
Checked: All objects are preloaded into the cache from the backing store. Lower level settings can override this setting by excluding specified objects.
Unchecked: No objects are preloaded. into the cache from the backing store. Lower level settings can override this setting by including specified objects.
Specifies whether object handles are loaded into the ObjectTable cache. The ObjectTable cache holds references (handles) to the objects themselves.
Handles are used in the object table. See The Role of the Object Table in TIBCO BusinessEvents Architect’s Guide for more details.
Checked: All object handles are preloaded. Lower level settings can override this setting by excluding handles for specified objects.
Unchecked: No object handles are preloaded into the cache from the backing store. Lower level settings can override this setting by including handles for specified objects.
If Preload Entities or Preload Handles or both are checked, this setting specifies the number of entity objects or handles (or both) to preload for each entity type whose objects or handles (or both) are configured to be preloaded.
The processing unit uses a local cache, of limited size, to improve access time to the concepts stored in the cluster cache. When a processing unit finds a concept instance in this local cache, the Check for Version setting determines whether the processing unit will use the instance directly, or instead check in the cluster cache for more recent version.
If Checked  (default value) The processing unit will check in the cluster cache for a more recent version. If a more recent version exists, it will be used, and will replace the one found in the local cache.
If Not Checked  The processing unit will use the instance found locally.
The processing unit has a special local cache used only for entities marked as Constant. Entities placed in this cache are only removed when they are explicitly deleted. If the processing unit finds an entity in the constant cache, it will use it without checking in the cluster.
If Checked  The entity is marked "Constant", and uses the constant cache.
If Not Checked  (default value) The entity does not use the constant cache.
The property See also Agent.AgentClassName.cacheTxn.updateCache is set to false (see Table 15, Inference Agent and Query Agent Properties (Sheet 1 of 4))
If checked: When a rule action changes the value of any of an entity’s properties, then the entity instance is evicted from the cache (updates are saved in the backing store)
Use as needed to improve performance and cache memory management. For example, if an entity is not accessed frequently, it may save memory in the cache if the entity is evicted from cache after it is updated.
If checked, the cache size is limited. Limited caches can be used only when a backing store is used to store entries in excess of the limit. The size of the entity cache is set in the Object Management section of the Cluster tab.
For objects that use Cache+Memory mode, check this checkbox to subscribe to subscription RTCs, so that changes to this object in one Rete Network are also changed in the Rete networks across all inference agents. See Using Locks to Ensure Data Integrity Within and Across Agents in TIBCO BusinessEvents Architect’s Guide for details.
Entity Level Object Overrides and Other Entity Level Settings
Many settings simply override the value of default settings. See Table 7, Cluster Tab — Cache OM — Domain Object Default Settings for general details about the use of each setting. The table below only provides details that are specific to overrides.
 
Memory Only Mode  If you set the mode for an entity to Memory Only, the rest of the properties in this section are not relevant and are ignored. Backing store is disabled for that entity.
Specifies whether objects of the specified type are loaded into the cache from the backing store on system startup (both normal startup and recovery).
default: Use the Preload Entities setting specified at the default level.
true: Objects of the specified type are preloaded into the cache from the backing store. If the default level setting is not to preload entities, you can use this override to preload selected entities.
false: No objects of the specified type are preloaded into the cache from the backing store. If the default level setting is to preload entities, you can use this override to not preload selected entities.
Specifies whether object handles for the specified type are loaded into the cache from the backing store on system startup (both normal startup and recovery).
default: Use the Preload Handles setting specified at the default level.
true: Handles for the specified type are preloaded into the cache from the backing store. If the default level setting is not to preload handles, you can use this override to preload selected entities’ handles.
false: No handles for the specified type are preloaded into the cache from the backing store. If the default level setting is to preload handles, you can use this override to preload selected entities’ handles.
If this object uses Cache+Memory mode, check this checkbox to subscribe to subscription RTCs, so that changes to this object in one Rete Network are also changed in the Rete networks across all inference agents. See Using Locks to Ensure Data Integrity Within and Across Agents in TIBCO BusinessEvents Architect’s Guide for details.
If this object uses Cache+Memory mode, and Subscribe Cluster is checked, specify a subscription preprocessor. This preprocessor is generally used to provide locking to ensure data consistency. See Using Locks to Ensure Data Integrity Within and Across Agents in TIBCO BusinessEvents Architect’s Guide for details.
Used only if the Backing Store > Enabled checkbox is checked. To exclude an entity from the backing store, uncheck the Has Backing Store checkbox.
Note  If you enable this override setting after the backing store has been set up, you must update the backing store schema. See Updating an Existing Backing Store Schema.
Used only if Oracle Coherence is the cache provider. Also used only if the query agent has enabled indexing: see be.agent.query.enable.filter.optimizer in Agent Classes Tab Settings and Properties. Also see Query Optimization in TIBCO BusinessEvents Developer’s Guide for more details and options.
Used with backing store to specify the length of string properties that exceed 255 characters (that is the actual contents stored in the column is more than 255 characters). Specifies the expected maximum length for the property. See String Properties that Exceed the DBMS Maximum Column Length for details.
This setting is for use only with ConceptReference type concept properties.
With a backing store, database updates related to a referring concept in a referenced concept can cause decreased performance. This happens when there are very many reverse references in a shared instance (referenced by many other instances).
To address this issue, set the value to false for ConceptReference type properties.
If you set the value to false, you must explicitly remove ConceptReference properties for deleted referenced concepts in the referring concept in your code.
For example, if employee is a ConceptReference type property in a concept acme, and smith is an instance of a concept type employee, then you would set Reverse References to true for the employee ConceptReference property, and you would add something like this to rules: