In PAS for OpenEdge, an agent is a single OS process that can run multiple ABL sessions concurrently. It is often referred to as a Multi-session Agent (MS Agent). A MS Agent can handle requests from multiple PAS for OpenEdge clients.

The ABL Session Manager in PAS for OpenEdge responds to client requests by communicating with an MS Agent process to assign an ABL session, to make sure that ABL code executes, and to ensure that a response is returned to the client. If there are no free sessions in one agent, it launches another agent.

You can configure properties like the number of sessions supported by an agent, the number of agent processes allowed in a server, and other in the /conf/openedge.properties file of a PAS for OpenEdge instance. It only applies to a single instance. All individual PAS for OpenEdge instances have their own openedge.properties file.

PAS for OpenEdge operates using either of the two session types:
  • Session managed—It means that a client is bound to a single session and the context is maintained between client requests. Subsequent client requests are handled in the context of the same session.
  • Session free—It means that a client is not bound to a single session. Subsequent requests from a client can be handled in different sessions.

A single PAS for OpenEdge instance supports both session-managed and session-free connections. The client request determines the mode of the session. Sessions running in different modes can run concurrently on a single instance of PAS for OpenEdge.