A resource can be any logical entity depending on your application. For data base products, a resource could be anything from a record to a block of records, to an entire data set. You define the resources for which serialization is required. You assign a name to each resource so that you or any other user can identify the resource for processing.

A request to access a resource for either shared or exclusive ownership is called a resource request. Each resource request indicates who the requestor is, in what state (either shared or exclusive) the resource is requested, and user-defined data that the requestor can specify for use in contention management. The resource request also might specify another type of user-defined data that the system is to record for recovery purposes.

XES keeps track of requests for a specific resource in a resource request queue.