presto-main/src/main/java/io/prestosql/util/JsonUtil.java/HashTable/calculateMaxFill
class HashTable:        private static int calculateMaxFill(int hashSize)
        {
            checkArgument(hashSize > 0, "hashSize must be greater than 0");
            int maxFill = (int) Math.ceil(hashSize * FILL_RATIO);
            if (maxFill == hashSize) {
                maxFill--;
            }
            checkArgument(hashSize > maxFill, "hashSize must be larger than maxFill");
            return maxFill;
        }