License queuing helps your users implement fair usage when licenses may not be immediately available. This feature is particularly useful for jobs scheduled for automatic execution. Without queuing enabled, checkout requests are immediately denied if the required license(s) are unavailable. If queuing is enabled, you determine its behavior; for example, the applications may be placed on hold until the necessary license(s) become available. (See LMX_Checkout for more information about how to implement license queuing behavior.)
License queuing has two variations: normal (the default) or fast queuing. By default, all license requests are appended to the end of the queue, regardless whether the request can be fulfilled immediately.
Alternatively, end users can enable fast queuing for their license server by changing a setting in their license server configuration file. Fast queuing allows requests that can be fulfilled immediately to be fulfilled.
For example, if a client is waiting for two licenses, and only one license is immediately available, another client that needs only one license can bypass the queue and take the single license without waiting. In this way, fast queuing allows smaller license requests to be processed more promptly and helps ensure higher license utilization. However, because it might enable users to bypass the queue, it does not necessarily implement fairness.
License queuing can be enabled by the end user by setting an environment variable. If you do not want to make license queuing available to end users, you can unset the environment variable as described in Controlling license behavior. Environment variables are described in detail in the LM-X End Users Guide.