Very slow select but uniq key, is there way to improve? - mysql

Question

On my authorization, i was looking user by his social id:
select * from users where yandex_id = 65250508;
And result is very bad: 1 row in set (11.25 sec)
Count of this table:
select count(id) from users;
+-----------+
| count(id) |
+-----------+
| 1852446 |
+-----------+
Also there is explain of my query:
explain select * from users where yandex_id = 65250508;
+------+-------------+-------+------+---------------------------------+------+---------+------+---------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+-------+------+---------------------------------+------+---------+------+---------+-------------+
| 1 | SIMPLE | users | ALL | UNIQ_1483A5E988FDD79D,yandex_id | NULL | NULL | NULL | 1820017 | Using where |
+------+-------------+-------+------+---------------------------------+------+---------+------+---------+-------------+
and describe of table:
describe users;
+-------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+----------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| ts | int(10) unsigned | NO | MUL | NULL | |
| last_ts | int(10) unsigned | NO | MUL | NULL | |
| last_mail | int(10) unsigned | NO | | NULL | |
| photo | varchar(32) | YES | | NULL | |
| name | varchar(48) | YES | | NULL | |
| email | varchar(48) | YES | UNI | NULL | |
| state | smallint(6) | NO | MUL | NULL | |
| ip | bigint(20) unsigned | NO | | NULL | |
| gender | varchar(1) | NO | | NULL | |
| facebook_id | varchar(64) | YES | UNI | NULL | |
| mailru_id | varchar(64) | YES | UNI | NULL | |
| vk_id | varchar(64) | YES | UNI | NULL | |
| yandex_id | varchar(64) | YES | UNI | NULL | |
| google_id | varchar(64) | YES | UNI | NULL | |
| roles | longtext | YES | | NULL | |
| is_active | tinyint(1) | NO | MUL | 1 | |
+-------------+---------------------+------+-----+---------+----------------+
17 rows in set (0.00 sec)

Answer 1

Try USE INDEX(update_index) in your query explicitly.
Sometimes the optimizer makes wrong choice in selecting the index because of which the query is becoming slow.

Answer 2

I have resolved my issue. So, problem was in that i'm using in where integer value, but my field vas defined as varchar, so when i have changed searching id to string, it starts working perfect
MariaDB [hrabr]> select * from users force index(yandex_id) where yandex_id = 65250508;
1 row in set (13.81 sec)
and with string:
MariaDB [hrabr]> select * from users force index(yandex_id) where yandex_id = '65250508';
1 row in set (0.00 sec)
I hope it will help someone!