Mysql性能：如何在數據庫中存儲文件樹？

Question

我試圖將文件存儲在數據庫中，並查詢文件夾的數量和大小。我的表格如下。

CREATE TABLE `files` (
`permission` varchar(10) DEFAULT NULL, 
`size` int(11) NOT NULL DEFAULT '0' COMMENT 'filesize', 
`date` varchar(20) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL, 
`time` varchar(20) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL, 
`path` varchar(1024) CHARACTER SET latin1 COLLATE latin1_general_ci DEFAULT NULL, 
KEY `path` (`path`(10)), 
KEY `path_2` (`path`(4)), 
KEY `size` (`size`) 
) ENGINE=MyISAM 

我的文件夾就像「????/some string」。我有大約38,333,316條記錄。 簡單查詢大約需要22秒。

mysql> select count(*),sum(size)/(1024.0*1024.0*1024.0) from files 
where path like '5___%' and size != 2048; 
+----------+----------------------------------+ 
| count(*) | sum(size)/(1024.0*1024.0*1024.0) | 
+----------+----------------------------------+ 
| 7900746 |      9019.6535 | 
+----------+----------------------------------+ 
1 row in set (22.89 sec) 

mysql> explain select count(*),sum(size)/(1024.0*1024.0*1024.0) 
     from files where path like '5___%' and size != 2048; 
--+-----------+-----+----+-------------- -+----+-------+----+--------+----------- 
id|select_type|table|type|possible_keys |key |key_len|ref |rows | Extra  
--+-----------+-----+----+----------------+----+-------+----+--------+----------- 
1| SIMPLE |files| ALL|path,path_2,size|NULL|NULL |NULL|38333316|Using where 
--+-----------+-----+----+----------------+----+-------+----+--------+----------- 
1 row in set (0.23 sec) 

有沒有辦法優化查詢，我可以加快以某種方式？ 通常我希望問類似這樣的一些問題：

path like '5___%' and size != 2048 
path like '3___%' and size != 2048 
path like '45__%' and size != 2048 

感謝阿曼。

Answer 1

嘗試這樣：

CREATE TABLE `directories` (
    `id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
    `path` varchar(1024) NOT NULL, 
    `permissions` varchar(10) NOT NULL, 
    `timestamp` datetime NOT NULL, 
    PRIMARY KEY (`id`), 
    KEY `path` (`path`(4)) 
) ENGINE=MyISAM DEFAULT CHARSET=latin1 

CREATE TABLE `files` (
    `directory_id` int(10) unsigned NOT NULL, 
    `filename` varchar(1024) NOT NULL, 
    `permissions` varchar(10) NOT NULL, 
    `timestamp` datetime NOT NULL, 
    `size` bigint(20) unsigned NOT NULL, 
    KEY `size` (`size`) 
) ENGINE=MyISAM DEFAULT CHARSET=latin1 

SELECT COUNT(*), SUM(size)/1073741824 FROM files WHERE directory_id IN(SELECT group_concat(id SEPARATOR ',') FROM directories WHERE path LIKE '5___%');