NOTE: Refer to Inequality interval estimation

If an interval comes from an inequality predicate, we can produce a more accurate result with _arrayMin and _arrayMax. This is similar to Conjunction forming a range query. For example, for an interval [10, inf.0], the cardinality estimate can be calculated using the _arrayMax histogram alone. This may produce a better estimate than _arrayUnique, which may overestimate due to insufficient deduplication.