presto-main/src/main/java/io/prestosql/operator/aggregation/state/LongDecimalWithOverflowStateFactory.java/GroupedLongDecimalWithOverflowState/setLongDecimal
class GroupedLongDecimalWithOverflowState:        @Override
        public void setLongDecimal(Slice value)
        {
            requireNonNull(value, "value is null");
            if (getLongDecimal() == null) {
                numberOfElements++;
            }
            unscaledDecimals.set(getGroupId(), value);
        }