text: -- for small cardinality the 64 bit hash perform worse, but for 1e10:
  -- 4 byte hash: 2.8832809652e10
  -- 8 byte hash: 0.9998568925e10
  -- but hence checking with 1e10 values takes too much time (~45 secs), this
  -- test is just to ensure that the result is different (and to document the
  -- outcome).
  
  SELECT uniqCombined(number)   FROM numbers(1e7);
  SELECT uniqCombined64(number) FROM numbers(1e7);
  