I set default_parallel=15
but when I did a
y = group z ALL;
x = foreach y generate SIZE(z);
the 2 lines generate a MR job with only 1 reducer.
I guess it's because SIZE() needs to count all the groups. but don't we
have the sort of cumulative/additive UDFs ?
it would be faster if we could parallelize SIZE()
Mark Wagner 2013-04-12, 00:52