I don't know why searching in my "cities" table is so slow. My query looking for a table "cities" located about 25km from the city. I use this simple query and the database takes almost 20 seconds to return results.
SELECT city_destination,distance FROM cities WHERE city_start='Wien' AND distance <= 25 ORDER BY distance ASC
Table engine is InnoDB. The table has approx. 7 millions of rows:
+--------------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------------+-------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| id_of_start | int(11) | NO | | NULL | |
| id_of_destination | int(11) | NO | | NULL | |
| city_start | text | NO | | NULL | |
| city_destination | text | NO | | NULL | |
| distance | double | NO | | NULL | |
+--------------------+-------------+------+-----+---------+----------------+
Can anyone advise me how to optimize a database or query?