The Worker queries your messaging system for messages and receives all of them. However, not all items are subsequently sent to the Retain Server.
If the link between the Worker and the messaging system is slow, consider placing the Worker on the messaging system's server or on a server that has a fast link to the messaging system.
The downside to this strategy is software updates.
When upgrading Retain software, you must update each Worker. Workers running on the Retain Server or on a separate server are upgraded together.