Under distributed JMS caching, participating Oracle Commerce Platform instances act as message sources and sinks for invalidation events. As installed, the Oracle Commerce Platform provides two components that are already configured as Patch Bay message sources and sinks:
/atg/dynamo/service/GSAInvalidatorServiceis configured as a Patch Bay message source. When a repository item that uses distributed JMS caching is updated, theGSAInvalidatorServicecomponent generates a JMS cache invalidation event of classatg.adapter.gsa.invalidator.MultiTypeInvalidationMessage./atg/dynamo/service/GSAInvalidatorReceiveris configured as a Patch Bay message sink and is a durable subscriber to invalidation topics. When one Oracle Commerce Platform instance generates a JMS cache invalidation event, theGSAInvalidatorReceiveron other instances receives the message and invalidates the appropriate item caches.
As installed, the Oracle Commerce Platform defines the SQL JMS topics that are used by the GSAInvalidatorService and GSAInvalidatorReceiver components.
To set up distributed JMS caching:
On each Oracle Commerce Platform instance that uses distributed JMS caching, enable the
GSAInvalidatorServiceby configuring the/atg/dynamo/Configurationcomponent as follows:gsaInvalidatorEnabled=trueOptionally, configure each SQL Repository’s
invalidatorServiceproperty to aGSAInvalidatorServicecomponent. If this property is not set, the repository uses the defaultGSAInvalidatorServicecomponent as a Patch Bay message source:/atg/dynamo/service/GSAInvalidatorService.Optionally, configure each
GSAInvalidatorServicecomponent’smaxItemsPerEventproperty. This property specifies the maximum number of cached items that a singleMultiTypeInvalidationMessagecan invalidate—by default, 200. If an event exceeds this limit, the entire cache of the invalidated item is flushed. A value of 0 ensures that every event always flushes the entire cache of the invalidated item.This mechanism can significantly reduce message payload, as a message that affects large numbers of items only needs to contain information about the item types to invalidate, rather than individual items.
Configure PatchBay in each participating Oracle Commerce Platform instance to access the same SQL JMS database tables.
