TIBCO ActiveMatrix® Adapter for OSIsoft PI is developed with PI SDK. For the TagEventPublicationService, the TIBCO ActiveMatrix® Adapter for OSIsoft PI would establish an event pipe for receiving events fro PI Data Archive. In the event the TagEventPublicationService processes slowly for the event loop (for example, EMS client is under reconnecting cycle), the messages are accumulated in the PI SDK, and accumulated messages would be processes in the next event.  

The limitation on maximum number of events per consumer is set at MAxUpdateQueue. Default is 50000 events per consumer. TotalUpdateQueue set the maximum number of events in Update Manager for all consumers (default at 1million events). 

This setting could be changed in PI System Management Tools under Operation, Tuning Parameters, Update Manager. For recommendation please refer to MaxUpdateQueue and TotalUpdateQueue Recommendations (https://customers.osisoft.com/s/knowledgearticle?knowledgeArticleUrl=3151OSI8).