Reading null value from datasets

Hello, I would like to ask if there were any particular ways to read or treat null (e.g. Name, Lastname,, Age..) value in a dataset using readCsvFile, without being forced to ignore them. Thanks for your time. Guido

Insufficient number of network buffers running on cluster

here these values come from. Thanks in advance for your time, Guido

GC on TaskManagers stats

- PS-Scavenge.Count: 3, PS-MarkSweep.Time: 5, load: 3.73. 4. Is it the “load” value tightly related? Sorry if it has been quite long and thanks a lot. Guido