In our production system we have seen that the calls to SearchResourceAvailabilityForRequirementGroup are some times slower than 7 secs.
Looking in app insights we can see that the following plugin is the main issue. For instance in a call to availability API that took 19.7 seconds (!!??) the plugin took 9.4secs.
Microsoft.Dynamics.ScheduleCommon.Fps.FpsPlugin
Duration | 9.4 s
Another step that also contributes to the overall time is this..
SDKmsdyn_RetrieveRequirementGroupCandidates
Duration | 6.3 s
Why is the API so slow?