Mongodb异常database.cpp:300

各位大神，谁有遇到过这种错误，我System.out.println(cursor.count());有140多W数据，但是cursor.hasNext()到了2W多条就没有了，如果我cursor.skip(30000)。就会出现以下异常：

Exception in thread "main" com.mongodb.MongoException: assertion src\mongo\db\database.cpp:300
    at com.mongodb.MongoException.parse(MongoException.java:82)
    at com.mongodb.DBApiLayer$MyCollection.__find(DBApiLayer.java:292)
    at com.mongodb.DBApiLayer$MyCollection.__find(DBApiLayer.java:273)
    at com.mongodb.DBCursor._check(DBCursor.java:368)
    at com.mongodb.DBCursor._hasNext(DBCursor.java:459)
    at com.mongodb.DBCursor.hasNext(DBCursor.java:484)