Just got my VirtualBox Sandbox running and am going through the tutorials (which are amazing btw!) and had a question that I was hoping folks out here could help me with.
I ran the Hive query (in Tutorial 1) for running a count on the NYSE_Stocks and then just on listing all the stocks (Select *)..and I am a bit puzzled on how the Select count(*) is slower than the Select *. Also, I noticed that the Select count(*) did not spawn any MR jobs.
Can anyone explain what is going on behind the covers for both these queries and why one is slower than the other?