License queuing, which must be enabled by your vendor, helps you 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. With queuing enabled, applications will be placed on hold until the necessary license(s) become available. (See also Environment variables.)
When license queuing is enabled, all license requests are appended to the end of the queue by default, regardless whether the request can be fulfilled immediately. Alternatively, you can enable fast queuing, which allows requests that can be fulfilled immediately to be fulfilled. Fast queuing can allow smaller license requests to be processed more promptly and help ensure higher license utilization. However, because it might enable users to bypass the queue, it does not necessarily implement fairness.
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.
To enable fast queuing, edit the FAST_QUEUE option in your license server configuration file. You can specify fast queuing for specified features or for all features; for example:
FAST_QUEUE = f1, f3
or
FAST_QUEUE = ALL