TIBCO BusinessEvents Cache Fundamentals
Read this section to grasp the basic ideas you need to understand and work with cache object management.
For greater depth, see TIBCO BusinessEvents Architect’s Guide.
- What is object management?
- Object management (or OM for short) refers to various ways that TIBCO BusinessEvents can manage the objects created by the actions of an inference agent’s rules and rule functions. You define the OM options in the project’s CDD file. The objects being managed of the types defined in the ontology, that is, concepts, scorecards and events. In the Project Design Tutorial, you used In Memory OM.
- What is a cache cluster?
- When you use Cache OM, objects are persisted redundantly in memory caches. Each TIBCO BusinessEvents engine (JVM) participates as a node in the cache cluster. The cache manager manages the objects across the JVMs.
- What’s the difference between the two supported cache providers?
- TIBCO BusinessEvents ships with an internally provided cache provider, TIBCO BusinessEvents DataGrid. This option is simple to set up and use.
- What is a distributed cache?
- TIBCO BusinessEvents uses a pre-configured distributed cache scheme.
- What is a backing store?
- With a distributed cache, one or more engines can fail without loss of data (depending on the number of backups of each object). However if all engines fail, the data is lost. For this reason it is common to write the objects to a database, known as the backing store.
- What are cache agents?
- Cache agents store and serve the cache data for the cluster. Tjey participate in distribution, partitioning and storage of the objects in the cluster.
- What other types of agents are there?
- Besides cache agents and inference agents, two other types of agents can join the cluster, too.
- How do agents use cached data?
- The inference agents can use objects in the cache as well as those they create from data coming in through channels (or create internally using rules and rule functions). Cached concept objects are shared by all agents in the cluster, scorecards are kept local to an agent, and events are clustered between the agents.
- What are modes?
- Each object type can use a different mode: Cache Only, Cache+Memory, and Memory Only.
- With Cache Only mode, how does data get from the Rete network to the cache?
- At the end of each RTC, that is, each "run to completion" cycle, data is flushed from the Rete network to the cache. In this way the Rete network does not become clogged with irrelevant data. (This behavior occurs when the entities are configured to use cache-only mode, which is the default and is strongly recommended.)
- With Cache Only mode, how does data get from the cache into the Rete network?
- Before each RTC, you must load the relevant data into the Rete network from the cache. If you do not then cached data that is needed by the rules triggered by incoming events is not present. For example, a request to create a new account arrives through a channel.
- How should I use Cache + Memory mode
- With cache plus memory mode, data is not flushed from the Rete network automatically. Use this only for constants or entities that change very seldom.
- How should I use Memory Only mode?
- Use this mode for entity types whose data is transient and does not need to be persisted.
- How do I change the number of backups of each object are kept?
- By default one backup of each cache object is maintained. Backups are maintained in different cache agents.
- How does TIBCO BusinessEvents deal with concurrency and locking?
- Multiple inference agents can run concurrently, sharing the same ontology and same cache cluster.
Copyright © TIBCO Software Inc. All rights reserved.