closeResultSet takes a very long time when the operation is aborted after 1%

XsvRdbTestInteger|CREATE TABLE `XsvRdbTestInteger` (

  `RtnID` int(11) NOT NULL AUTO_INCREMENT,

  `RtmID` int(11) NOT NULL,

  `RtnInteger` int(11) DEFAULT NULL,

  PRIMARY KEY (`RtnID`),

  KEY `IdxFkRtnRdb` (`RtmID`)

) ENGINE=InnoDB AUTO_INCREMENT=16376618 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin

long executeQueryDur = 0;

long closeResultSetDur = 0;

long totalTime = -System.currentTimeMillis();

try (final Statement stmt =

		con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, ResultSet.CLOSE_CURSORS_AT_COMMIT)) {

	if (_fetchSize != null) {

		stmt.setFetchSize(_fetchSize.intValue());

	}

	executeQueryDur = -System.currentTimeMillis();

	try (final ResultSet rs = stmt.executeQuery("SELECT RtnID,RtmID,RtnInteger FROM XsvRdbTestInteger")) {

		executeQueryDur += System.currentTimeMillis();

		int step = 0;

		while (rs.next()) {

			step++;

			if (_maxRows != null && step > _maxRows.intValue()) {

				_log4j.debug("### abbruch {}/{}, fetchSize {}", step, total, _fetchSize);

				break;

			}

		}

		closeResultSetDur = -System.currentTimeMillis();

	}

	closeResultSetDur += System.currentTimeMillis();

}

totalTime += System.currentTimeMillis();

final NumberFormat nf = NumberFormat.getInstance(Locale.GERMANY);

_log4j.info("totalTime=" + totalTime + " ms, executeQuery=" + executeQueryDur + " ms, closeResultSet=" + closeResultSetDur

		+ " ms, fetchSize=" + (_fetchSize == null ? "not set" : nf.format(_fetchSize)) + ", interrupt after " + nf.format(_maxRows)

		+ " rows, " + nf.format(total) + " rows in table");