Slow query help

[Flavio Pompermaier]

Hi to all,
I'm running a query like this one on my Phoenix 4.13 (on CDH 5.11.2):

SELECT COUNT(*) FROM (
  SELECT DISTINCT(SOMEFIELD)
  FROM TEST.MYTABLE
  WHERE VALID = TRUE AND SOMEFIELD IS NOT NULL
)

Unfortunately the query timeouts (timeout is 10 min).... Any suggestion
about how to tune my installation?

Best,
Flavi