Simply put, the first query only hits the metastore database and doesn't launch a map reduce job.
On the other hand, the second query runs a map side mapreduce job
Interestingly enough, for the first query, hive makes some good decisions on how to read the data. A simple select * could essentially simply be fetching a file from hdfs like an hdfs get... simplified, but true.
Hi Michael, I'm still trying to figure out where to find that log (is there any folder?).
I've tried finding the Query ID that Hive shows once i execute a query, but couldn't find it.
Query ID = root_20161205190741_fb2a555d-1633-404d-9128-0c3696d2d56a
Until now, i've just found the following exception (through CLI) after execution fails: