Backing Store Write Strategy

TIBCO BusinessEvents implements the cache-aside strategy for writing to the backing store, in which the inference agent handles all writes simultaneously, and offers transaction control.

With cache-aside database write strategy, inference agents manage writes to the cache, the local L1 cache, and the backing store, simultaneously, in the post RTC phase. (The cache agent reads from the backing store, but does not write to it.)

Cache-aside allows batching of writes to the backing store and provides thread and queue size controls.

Starting a Minimum Number (Quorum) of Cache Agents

At system startup, one node in the cache cluster loads objects from the backing store to the cache cluster, according to the preloading settings (see Storage and Retrieval of Entity Objects). Any node in the cluster can perform the preloading.

Before preloading begins, you must ensure that enough cache agents have started to hold the objects from the backing store. The cluster does not start processing incoming data until the required objects have been loaded into the cache.

See TIBCO BusinessEvents Configuration Guide, for details about specifying the minimum number of cache agents that must start before cache loading begins.

After the specified number of cache agents has started, the processing unit that acquires the lock first performs the cache loading. Any processing unit can acquire the lock. All agents wait until backing store data has finished loading before they start.

Note: This setting does not affect runtime operation of the deployed application. Deployed applications continue to run even if one or more cache agents fails and the quorum is no longer met. A warning message is written to the log file.