我覺得下面的查詢速度太慢:理念,提高此查詢索引
(1679.1ms)
SELECT `media_files` . *
FROM `media_files`
INNER JOIN `playlist_media_files` ON `media_files`.`id` = `playlist_media_files`.`media_file_id`
WHERE `media_files`.`type`
IN (
'AudioFile'
)
AND `playlist_media_files`.`playlist_id` =7
ORDER BY media_files.artist ASC , media_files.release_year ASC , media_files.album ASC , media_files.disc_number ASC , media_files.position ASC
說明:
+----+-------------+----------------------+--------+---------------------------------------------------------------------------------------+-------------------------------------------+---------+---------------------------------------------------------+------+---------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+----------------------+--------+---------------------------------------------------------------------------------------+-------------------------------------------+---------+---------------------------------------------------------+------+---------------------------------+
| 1 | SIMPLE | playlist_media_files | ref | index_playlist_media_files_on_playlist_id,index_playlist_media_files_on_media_file_id | index_playlist_media_files_on_playlist_id | 4 | const | 3782 | Using temporary; Using filesort |
| 1 | SIMPLE | media_files | eq_ref | PRIMARY,index_media_files_on_type | PRIMARY | 4 | mydb.playlist_media_files.media_file_id | 1 | Using where |
+----+-------------+----------------------+--------+---------------------------------------------------------------------------------------+-------------------------------------------+---------+---------------------------------------------------------+------+---------------------------------+
每列索引。 任何MySQL專家都可以通過查看解釋來了解如何改進它?
的多個ORDER BY被查殺性能。
編輯:從意見
更新刪除私人網址:看來我可以爲後期ORDER BY排序像做concat(..fields..) AS sort
。
每張表中有多少行以及索引基數是多少? 'SHOW INDEXES FROM tablename' – piotrm