Index: include/classes/api/services/CItemGeneral.php
===================================================================
--- include/classes/api/services/CItemGeneral.php	(revision 59866)
+++ include/classes/api/services/CItemGeneral.php	(working copy)
@@ -566,53 +566,16 @@
 	 * @param type $checkMax
 	 */
 	protected function checkUseInGraphAxis(array $itemids, $checkMax = false) {
-		if ($checkMax) {
-			$filter = array('ymax_itemid' => $itemids);
-			$itemIdColumn = 'ymax_itemid';
-			$typeColumn = 'ymax_type';
-		}
-		else {
-			$filter = array('ymin_itemid' => $itemids);
-			$itemIdColumn = 'ymin_itemid';
-			$typeColumn = 'ymin_type';
-		}
+		$itemIdColumn = $checkMax ? 'ymax_itemid' : 'ymin_itemid';
+		$error = $checkMax
+			? 'Could not delete these items because some of them are used as MAX values for graphs.'
+			: 'Could not delete these items because some of them are used as MIN values for graphs.';
 
-		// make it work for both graphs and graph prototypes
-		$filter['flags'] = array(
-			ZBX_FLAG_DISCOVERY_PROTOTYPE,
-			ZBX_FLAG_DISCOVERY_NORMAL,
-			ZBX_FLAG_DISCOVERY_CREATED
-		);
+		$result = DBselect('SELECT NULL FROM graphs WHERE '.dbConditionInt($itemIdColumn, $itemids), 1);
 
-		// check if the items are used in Y axis min/max values in any graphs
-		$graphs = API::Graph()->get(array(
-			'output' => array($itemIdColumn, $typeColumn, 'graphtype'),
-			'filter' => $filter
-		));
-
-		$updateGraphs = array();
-		foreach ($graphs as &$graph) {
-			// check if Y type is actually set to GRAPH_YAXIS_TYPE_ITEM_VALUE
-			if ($graph[$typeColumn] == GRAPH_YAXIS_TYPE_ITEM_VALUE) {
-				if ($checkMax) {
-					self::exception(ZBX_API_ERROR_PARAMETERS, 'Could not delete these items because some of them are used as MAX values for graphs.');
-				}
-				else {
-					self::exception(ZBX_API_ERROR_PARAMETERS, 'Could not delete these items because some of them are used as MIN values for graphs.');
-				}
-			}
-			else {
-				$graph[$itemIdColumn] = null;
-				$updateGraphs[] = $graph;
-			}
+		if (DBfetch($result)) {
+			self::exception(ZBX_API_ERROR_PARAMETERS, $error);
 		}
-
-		// if there are graphs, that have an y*_itemid column set, but the
-		// y*_type column is not set to GRAPH_YAXIS_TYPE_ITEM_VALUE, set y*_itemid to NULL.
-		// Otherwise we won't be able to delete them.
-		if ($updateGraphs) {
-			API::Graph()->update($updateGraphs);
-		}
 	}
 
 	/**