Сложный запрос MySQL все еще использует файловую сортировку, хотя индексы существуют

У меня есть таблица Joomla с тысячами строк содержимого (примерно 3 миллиона). У меня проблемы с переписыванием запросов к базе данных, чтобы они выполнялись как можно быстрее при запросе таблиц.

Вот мой полный запрос:

SELECT cc.title AS category, a.id, a.title, a.alias, a.title_alias, a.introtext, a.fulltext, a.sectionid, a.state, a.catid, a.created, a.created_by, a.created_by_alias, a.modified, a.modified_by, a.checked_out, a.checked_out_time, a.publish_up, a.publish_down, a.attribs, a.hits, a.images, a.urls, a.ordering, a.metakey, a.metadesc, a.access, CASE WHEN CHAR_LENGTH(a.alias) THEN CONCAT_WS(":", a.id, a.alias) ELSE a.id END AS slug, CASE WHEN CHAR_LENGTH(cc.alias) THEN CONCAT_WS(":", cc.id, cc.alias) ELSE cc.id END AS catslug, CHAR_LENGTH( a.`fulltext` ) AS readmore, u.name AS author, u.usertype, g.name AS groups, u.email AS author_email
FROM j15_content AS a
LEFT JOIN j15_categories AS cc
ON a.catid = cc.id
LEFT JOIN j15_users AS u
ON u.id = a.created_by
LEFT JOIN j15_groups AS g
ON a.access = g.id
WHERE 1
AND a.access <= 0
AND a.catid = 108
AND a.state = 1
AND ( publish_up = '0000-00-00 00:00:00' OR publish_up <= '2012-02-08 00:16:26' )
AND ( publish_down = '0000-00-00 00:00:00' OR publish_down >= '2012-02-08 00:16:26' )
ORDER BY a.title, a.created DESC
LIMIT 0, 10

Вот результат EXPLAIN:

 +----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-----------------------------+
| id | select_type | table | type   | possible_keys                                         | key       | key_len | ref                       | rows    | Extra                       |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-----------------------------+
|  1 | SIMPLE      | a     | ref    | idx_access,idx_state,idx_catid,idx_access_state_catid | idx_catid | 4       | const                     | 3108187 | Using where; Using filesort |
|  1 | SIMPLE      | cc    | const  | PRIMARY                                               | PRIMARY   | 4       | const                     |       1 |                             |
|  1 | SIMPLE      | u     | eq_ref | PRIMARY                                               | PRIMARY   | 4       | database.a.created_by     |       1 |                             |
|  1 | SIMPLE      | g     | eq_ref | PRIMARY                                               | PRIMARY   | 1       | database.a.access         |       1 |                             |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-----------------------------+

И чтобы показать, какие индексы существуют, ПОКАЖИТЕ ИНДЕКС ИЗ j15_content:

+-------------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table       | Non_unique | Key_name               | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| j15_content |          0 | PRIMARY                |            1 | id          | A         |     3228356 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_section            |            1 | sectionid   | A         |           2 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_access             |            1 | access      | A         |           1 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_checkout           |            1 | checked_out | A         |           2 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_state              |            1 | state       | A         |           2 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_catid              |            1 | catid       | A         |           6 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_createdby          |            1 | created_by  | A         |           1 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | title                  |            1 | title       | A         |      201772 |        4 | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_access_state_catid |            1 | access      | A         |           1 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_access_state_catid |            2 | state       | A         |           2 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_access_state_catid |            3 | catid       | A         |           7 |     NULL | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_title_created      |            1 | title       | A         |     3228356 |        8 | NULL   |      | BTREE      |         |
| j15_content |          1 | idx_title_created      |            2 | created     | A         |     3228356 |     NULL | NULL   |      | BTREE      |         |
+-------------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+

Как видите, есть несколько фрагментов данных взято из базы. Теперь я проверил, упростив запрос, что реальная проблема связана с предложением ORDER BY. Без упорядочивания результатов запрос достаточно отзывчивый, вот объяснение:

+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-------------+
| id | select_type | table | type   | possible_keys                                         | key       | key_len | ref                       | rows    | Extra       |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-------------+
|  1 | SIMPLE      | a     | ref    | idx_access,idx_state,idx_catid,idx_access_state_catid | idx_catid | 4       | const                     | 3108187 | Using where |
|  1 | SIMPLE      | cc    | const  | PRIMARY                                               | PRIMARY   | 4       | const                     |       1 |             |
|  1 | SIMPLE      | u     | eq_ref | PRIMARY                                               | PRIMARY   | 4       | database.a.created_by     |       1 |             |
|  1 | SIMPLE      | g     | eq_ref | PRIMARY                                               | PRIMARY   | 1       | database.a.access         |       1 |             |
+----+-------------+-------+--------+-------------------------------------------------------+-----------+---------+---------------------------+---------+-------------+

Как видите, сервер убивает фатальная файловая сортировка. С таким количеством строк я изо всех сил стараюсь оптимизировать все с помощью индексов, но с этим все еще что-то не так. Любой вклад будет очень признателен.

Безуспешная попытка использования FORCE INDEX:

explain     SELECT cc.title AS category, a.id, a.title, a.alias, a.title_alias, a.introtext, a.fulltext, a.sectionid, a.state, a.catid, a.created, a.created_by, a.created_by_alias, a.modified, a.modified_by, a.checked_out, a.checked_out_time, a.publish_up, a.publish_down, a.attribs, a.hits, a.images, a.urls, a.ordering, a.metakey, a.metadesc, a.access, CASE WHEN CHAR_LENGTH(a.alias) THEN CONCAT_WS(":", a.id, a.alias) ELSE a.id END AS slug, CASE WHEN CHAR_LENGTH(cc.alias) THEN CONCAT_WS(":", cc.id, cc.alias) ELSE cc.id END AS catslug, CHAR_LENGTH( a.`fulltext` ) AS readmore, u.name AS author, u.usertype, g.name AS groups, u.email AS author_email
    ->     FROM bak_content AS a
    ->     FORCE INDEX (idx_title_created)
    ->     LEFT JOIN bak_categories AS cc
    ->     ON a.catid = cc.id
    ->     LEFT JOIN bak_users AS u
    ->     ON u.id = a.created_by
    ->     LEFT JOIN bak_groups AS g
    ->     ON a.access = g.id
    ->     WHERE 1
    ->     AND a.access <= 0
    ->     AND a.catid = 108
    ->     AND a.state = 1
    ->     AND ( publish_up = '0000-00-00 00:00:00' OR publish_up <= '2012-02-08
    ->     AND ( publish_down = '0000-00-00 00:00:00' OR publish_down >= '2012-0
    ->     ORDER BY a.title, a.created DESC
    ->     LIMIT 0, 10;

Результат:

+----+-------------+-------+--------+---------------+---------+---------+-------
| id | select_type | table | type   | possible_keys | key     | key_len | ref
+----+-------------+-------+--------+---------------+---------+---------+-------
|  1 | SIMPLE      | a     | ALL    | NULL          | NULL    | NULL    | NULL
|  1 | SIMPLE      | cc    | const  | PRIMARY       | PRIMARY | 4       | const
|  1 | SIMPLE      | u     | eq_ref | PRIMARY       | PRIMARY | 4       | database
|  1 | SIMPLE      | g     | eq_ref | PRIMARY       | PRIMARY | 1       | database
+----+-------------+-------+--------+---------------+---------+---------+-------