diff --git a/src/zabbix_server/housekeeper/housekeeper.c b/src/zabbix_server/housekeeper/housekeeper.c
index b8584b9..675b8cb 100644
--- a/src/zabbix_server/housekeeper/housekeeper.c
+++ b/src/zabbix_server/housekeeper/housekeeper.c
@@ -1092,7 +1092,33 @@ static int	housekeeping_events(int now)
 		return 0;
 
 	for (rule = rules; NULL != rule->table; rule++)
+	{
+		/* set min_clock here because min(clock) calculation of events table in
+		 * housekeeping_process_rule() might be too slow.
+		 * assume that the event with the smallest eventid has the smallest clock.
+		 */
+
+		DB_RESULT	result;
+		DB_ROW		row;
+		zbx_uint64_t	id = 0;
+
+		result = DBselect("select eventid from events where %s order by eventid limit 1", rule->filter);
+		if (NULL != (row = DBfetch(result)) && SUCCEED != DBis_null(row[0]))
+			ZBX_STR2UINT64(id, row[0]);
+		DBfree_result(result);
+
+		if (0 < id)
+		{
+			result = DBselect("select clock from events where eventid=%ld", id);
+			if (NULL != (row = DBfetch(result)) && SUCCEED != DBis_null(row[0]))
+				rule->min_clock = atoi(row[0]);
+			else
+				rule->min_clock = now;
+			DBfree_result(result);
+		}
+
 		deleted += housekeeping_process_rule(now, rule);
+	}
 
 	return deleted;
 #undef ZBX_HK_EVENT_RULE