Hi I have Spark job which does group by and I cant avoid it because of my use case. I have large dataset around 1 TB which I need to process/update in DataFrame. Now my jobs shuffles huge data and slows things because of shuffling and groupby. One reason I see is my data is skew some of my group by keys are empty. How do I avoid empty group by keys in DataFrame? Does DataFrame avoid empty group by key? I have around 8 keys on which I do group by.

sourceFrame.select("blabla").groupby("col1","col2","col3",..."col8").agg("bla bla");