如何更优化此查询？
SELECT COUNT(*) AS releases, SUM(bt.size) AS sum_size, SUM(a.download_count) download_count FROM bb_bt_torrents bt LEFT JOIN bb_attachments_desc a ON (a.attach_id = bt.attach_id) WHERE bt.poster_id = 35979;
此查询可以在大约25秒的时间内运行。 我有什么选择？
以下是给我的解释：
+----+-------------+-------+--------+---------------+-----------+---------+------------------------+--------+-------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+---------------+-----------+---------+------------------------+--------+-------+
| 1 | SIMPLE | bt | ref | poster_id | poster_id | 3 | const | 178770 | |
| 1 | SIMPLE | a | eq_ref | PRIMARY | PRIMARY | 3 | unionpeer.bt.attach_id | 1 | |
+----+-------------+-------+--------+---------------+-----------+---------+------------------------+--------+-------+
表格定义：
CREATE TABLE IF NOT EXISTS `bb_attachments_desc` (
`attach_id` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
`physical_filename` varchar(255) NOT NULL DEFAULT '',
`real_filename` varchar(255) NOT NULL DEFAULT '',
`download_count` mediumint(8) unsigned NOT NULL DEFAULT '0',
`comment` varchar(255) NOT NULL DEFAULT '',
`extension` varchar(100) NOT NULL DEFAULT '',
`mimetype` varchar(100) NOT NULL DEFAULT '',
`filesize` int(20) NOT NULL DEFAULT '0',
`filetime` int(11) NOT NULL DEFAULT '0',
`thumbnail` tinyint(1) NOT NULL DEFAULT '0',
`tracker_status` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`attach_id`),
KEY `filetime` (`filetime`),
KEY `filesize` (`filesize`),
KEY `physical_filename` (`physical_filename`(10))
) ENGINE=InnoDB DEFAULT CHARSET=cp1251;
CREATE TABLE IF NOT EXISTS `bb_bt_torrents` (
`torrent_id` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
`info_hash` varbinary(20) NOT NULL,
`post_id` mediumint(8) unsigned NOT NULL DEFAULT '0',
`poster_id` mediumint(9) NOT NULL DEFAULT '0',
`topic_id` mediumint(8) unsigned NOT NULL DEFAULT '0',
`forum_id` smallint(5) unsigned NOT NULL DEFAULT '0',
`attach_id` mediumint(8) unsigned NOT NULL DEFAULT '0',
`size` bigint(20) unsigned NOT NULL DEFAULT '0',
`reg_time` int(11) NOT NULL DEFAULT '0',
`call_seed_time` int(11) NOT NULL DEFAULT '0',
`complete_count` mediumint(8) unsigned NOT NULL DEFAULT '0',
`seeder_last_seen` int(11) NOT NULL DEFAULT '0',
`tor_status` tinyint(4) NOT NULL DEFAULT '0',
`tor_status_uid` mediumint(8) NOT NULL DEFAULT '0',
`tor_status_time` int(11) NOT NULL DEFAULT '0',
`tor_type` tinyint(1) NOT NULL DEFAULT '0',
`speed_up` mediumint(8) NOT NULL DEFAULT '0',
`speed_down` mediumint(8) NOT NULL DEFAULT '0',
`last_seeder_uid` mediumint(9) NOT NULL DEFAULT '0',
`donor` tinyint(2) NOT NULL DEFAULT '-1',
`donor_get_time` int(11) NOT NULL DEFAULT '0',
`rutracker_ids` tinyint(1) NOT NULL DEFAULT '0',
`dht` tinyint(1) NOT NULL DEFAULT '2',
PRIMARY KEY (`torrent_id`),
UNIQUE KEY `post_id` (`post_id`),
UNIQUE KEY `topic_id` (`topic_id`),
UNIQUE KEY `attach_id` (`attach_id`),
UNIQUE KEY `info_hash` (`info_hash`),
KEY `reg_time` (`reg_time`),
KEY `forum_id` (`forum_id`),
KEY `poster_id` (`poster_id`),
KEY `size` (`size`),
KEY `tor_status` (`tor_status`),
KEY `tor_status_time` (`tor_status_time`),
KEY `tor_status_2` (`tor_status`,`tor_status_time`)
) ENGINE=InnoDB DEFAULT CHARSET=cp1251;
我考虑重写此查询，但不知道如何。