Inactivity device based on speed and location.

[Jeferex]

One thing I think should be improved is Inactivity. By default, a device is considered inactive when speed is <= 0 but I have some devices that always send speed = 0 so they are considered inactive even though they are moving. So I think, to consider a device inactive, speed and location should be considered.

[vitalidze]

I am thinking about this issue for several days and can't find a scalable way of implementing it. The main hardness is to find out previous non-idle position when user logs in. For speed it is found with single simple SQL query, but for location it cannot be done with simple query because it requires to look into previous position. So it either requires additional JOIN of same positions table, or user-defined variables (works for MySQL and H2, but not for PostgreSQL), or load all data in memory and then filter programmatically in java. All these options scale badly if amount of data grows, and I'm out of ideas.

Maybe there are any other thoughts of this feature implementation?

I am thinking about adding a check box to just allow to disable this 'idle' calculation for devices that don't send speed as a surrender solution.