Members of a cache cluster are defined at the node level. Any and all agents deployed to those nodes participate in the cluster, according to their function.
A node can be configured to contain inference agents, or query agents, or both. When a node is configured to be a cache server, however, it should be used for cache data storage only. A cache server node can also contain inference agents and query agents. However for production systems it is recommended that cache server nodes do no other work.
An inference agent can be described as a rule session. Inference agents are supported in all object management options, but in Cache OM systems, inference agents are connected to the cache cluster, enabling fault tolerance of engine processes and cache data, as well as load balancing.
In TIBCO Designer, one BAR resource (added within an EAR resource) is used to configure an inference agent. For example, you can configure an inference agent with a selection of rule sets to provide business logic on the underlying objects in the cluster.
An inference agent group is a group of identical agents running in different engines concurrently, to enable load balancing and fault tolerance (see
Load Balancing and Fault Tolerance Between Inference Agents). All agents within a group have the same rules deployed and service the same destinations.
The purpose of cache servers is to store and serve cache data for the cluster. A dedicated cache server node is a non-reasoning agent used as a storage node only. It does not instantiate rule sets or query sets. Cache servers are responsible for object management. They participate in distribution, partitioning and storage of the objects in the cluster.
Query agents are available only in TIBCO BusinessEvents Enterprise Suite. They are used only with Cache object management. Query agents enable you to query the objects in the cache using an SQL-like syntax.
A query agent is a non-reasoning agent that and has read-only access to the underlying objects in the cache cluster. A query agent has no Rete network.