Editing Message-oriented middleware (section)

==Disadvantages==
The primary disadvantage of many message-oriented middleware systems is that they require an extra component in the [[software architecture|architecture]], the message transfer agent ([[message broker]]). As with any [[system]], adding another component can lead to reductions in [[computer performance|performance]] and reliability, and can also make the system as a whole more difficult and expensive to [[software maintenance|maintain]].

In addition, many inter-application communications have an intrinsically [[Synchronization (computer science)|synchronous]] aspect, with the sender specifically wanting to wait for a reply to a message before continuing (see [[real-time computing]] and [[near real time|near-real-time]] for extreme cases). Because message-based [[data communication|communication]] inherently functions asynchronously, it may not fit well in such situations. That said, most MOM systems have facilities to group a request and a response as a single pseudo-synchronous transaction.

With a synchronous messaging system, the calling function does not return until the called function has finished its task. In a [[loose coupling|loosely coupled]] asynchronous system, the calling client can continue to load work upon the recipient until the resources needed to handle this work are depleted and the called component fails. Of course, these conditions can be minimized or avoided by monitoring performance and adjusting message flow, but this is work that is not needed with a synchronous messaging system. The important thing is to understand the advantages and liabilities of each kind of system. Each system is appropriate for different kinds of tasks. Sometimes, a combination of the two kinds of systems is required to obtain the desired behavior.