mysql 索引的使用

Question

mysql> explain SELECT * FROM uchome_feed force index(uid) WHERE uid IN ('0',16,109,164,182,238,268,388,403,475);
+----+-------------+-------------+------+---------------+------+---------+------+--------+-------------+
| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows   | Extra       |
+----+-------------+-------------+------+---------------+------+---------+------+--------+-------------+
|  1 | SIMPLE      | uchome_feed | ALL  | uid           | NULL | NULL    | NULL | 449779 | Using where | 
+----+-------------+-------------+------+---------------+------+---------+------+--------+-------------+强制使用索引居然也没用，mysql in操作难道不走索引？？
该如何优化？？

Answer 1

贴一下：
show index from uchome_feed;看一下。

Answer 2

mysql> show index from uchome_feed;
+-------------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table       | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| uchome_feed |          0 | PRIMARY  |            1 | feedid      | A         |      449779 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | uid      |            1 | uid         | A         |      449779 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | uid      |            2 | dateline    | A         |      449779 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | dateline |            1 | dateline    | A         |       24987 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | hot      |            1 | hot         | A         |          37 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | id       |            1 | id          | A         |        1578 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | id       |            2 | idtype      | A         |        3627 |     NULL | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | icon     |            1 | icon        | A         |          73 |       20 | NULL   |      | BTREE      |         | 
| uchome_feed |          1 | uids     |            1 | uid         | A         |      449779 |     NULL | NULL   |      | BTREE      |         | 
+-------------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
9 rows in set (0.01 sec)