When a registrant starts the form process, they are actively monitored in the system's memory. This monitoring tracks and reserves any inventory the registrant selects while the registrant is incomplete. This inventory reservation prevents overbooking.
If the registrant stops going through the form and the time limit is reached, the system cancels the items the registrant selected. The canceled items are returned to the inventory pool.
As the registrant takes up system memory, the system limits the number of spots available for each form. This number can range from 150 - 900 slots based on the current system resources.
When the slot limit is reached, the registrant sees a notice on the form that the form is unavailable. If the registrant waits, the system checks every 10 seconds to see if a spot has freed up.
When the Plan > Options > "Incomplete registrations count..." setting has a value of 5,000 minutes, an incomplete registration that does not continue through the form to the Confirmation page takes up one system memory spot for 83 hours.
The system default of 10 minutes is usually enough. If more time is needed, increasing the setting to 30 or 60 minutes is often all that is necessary.
When setting the time value, an event manager needs to weigh how long a registrant may pause in the form. The event manager also needs to weigh how long the event manager wants the inventory to remain unavailable to other registrants. The event manager also needs to weigh how many people the event manager expects to register in the same timeframe.
A higher time value allows an incomplete registration to pause on the form for longer. A higher time value limits the number of incomplete registrations that can access the form simultaneously.
A higher time value and a higher expected number of registrants increases the likelihood of instances when registrants are told that the form is currently unavailable. In those instances, registrants need to wait to register.
> NOTE - Proper management of the above settings for the event should help avoid this ever becoming an issue.