Signature updates on holidays - How does it work?

Surely it is a stupid question , but I have always wondered how the "antivirus signatures update" process works.

I imagine that there is not an army of employees checking "virus signatures" by hand , building the "update pack" and making it available for all of us, but even if an automatic mode exists I wonder how it can make available updates on holidays (when, I hope, ESET staff is relaxing at home )

 

There's nothing like holidays when everybody would relax far from computers. At least 1-2 updates are issued every day, no matter whether it's holiday or whatever.