PDO比mysql查询慢得多？

我在PHP中使用PDO对象来运行MYSQL查询，并且我一直在尝试处理查询以加速它。该查询如下，在我的PHP文件中看到：

PDO比mysql查询慢得多？

$query = 
"SELECT SQL_NO_CACHE f.position, s.item_id, s.item_type, s.title, s.caption, s.date 
FROM apiv2.search_all s 
INNER JOIN apiv2.tags t 
USING(item_id, item_type) 
LEFT JOIN apiv2.featured f 
ON t.item_id = f.item_id AND t.item_type = f.item_type AND f.feature_type = :id 
WHERE t.tag = 'FeaturedContent' 
ORDER BY position IS NULL, position ASC, date"; 

$mysql_vars[':id'] = $id; 
$stmt = $connection->prepare($query); 
$stmt->execute($vars); 
$data = $stmt->fetchAll(PDO::FETCH_ASSOC);

此查询运行显著不同，这取决于我是否包含ORDER BY子句，但只能在MYSQL控制台：

- MYSQL Console with ORDER BY: 1.07 sec 
    - starting 0.000141 
    - Opening tables 0.001416 
    - System lock 0.000003 
    - Table lock 0.000007 
    - init 0.000021 
    - checking permissions 0.000001 
    - checking permissions 0.000036 
    - optimizing 0.000027 
    - statistics 0.000027 
    - preparing 0.000015 
    - Creating tmp table 0.003440 
    - executing 0.000001 
    - Copying to tmp table 1.050029 
    - Sorting result 0.013097 
    - Sending data 0.000295 
    - end 0.000002 
    - removing tmp table 0.002045 
    - end 0.000003 
    - query end 0.000002 
    - freeing items 0.000331 
    - logging slow query 0.000002 
    - cleaning up 0.000007 
- MYSQL Console unordered output: .0053 sec 
    - starting 0.000076 
    - Opening tables 0.001506 
    - System lock 0.000002 
    - Table lock 0.000005 
    - init 0.000015 
    - checking permissions 0.000001 
    - checking permissions 0.000022 
    - optimizing 0.000012 
    - statistics 0.000021 
    - preparing 0.000011 
    - executing 0.000001 
    - Sending data 0.002895 
    - end 0.000002 
    - query end 0.000001 
    - freeing items 0.000078 
    - logging slow query 0.000000 
    - cleaning up 0.000002 
- PDO Prepared stmt ORDER BY: 1.18 sec 
    - 'Status' => 'starting', 'Duration' => '0.000147' 
    - 'Status' => 'Opening tables', 'Duration' => '0.000784' 
    - 'Status' => 'System lock', 'Duration' => '0.000004' 
    - 'Status' => 'Table lock', 'Duration' => '0.000007' 
    - 'Status' => 'init', 'Duration' => '0.000017' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000002' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000028' 
    - 'Status' => 'optimizing', 'Duration' => '0.000018' 
    - 'Status' => 'statistics', 'Duration' => '0.000026' 
    - 'Status' => 'preparing', 'Duration' => '0.000014' 
    - 'Status' => 'Creating tmp table', 'Duration' => '0.002112' 
    - 'Status' => 'executing', 'Duration' => '0.000001' 
    - 'Status' => 'Copying to tmp table', 'Duration' => '1.033056' 
    - 'Status' => 'Sorting result', 'Duration' => '0.013759' 
    - 'Status' => 'Sending data', 'Duration' => '0.073144' 
    - 'Status' => 'end', 'Duration' => '0.000003' 
    - 'Status' => 'removing tmp table', 'Duration' => '0.001999' 
    - 'Status' => 'end', 'Duration' => '0.000004' 
    - 'Status' => 'query end', 'Duration' => '0.000007' 
    - 'Status' => 'freeing items', 'Duration' => '0.000118' 
    - 'Status' => 'logging slow query', 'Duration' => '0.000001' 
    - 'Status' => 'cleaning up', 'Duration' => '0.000003' 
- PDO Prepared stmt unordered output: 1.06 sec 
    - 'Status' => 'starting', 'Duration' => '0.000074' 
    - 'Status' => 'Opening tables', 'Duration' => '0.001364' 
    - 'Status' => 'System lock', 'Duration' => '0.000004' 
    - 'Status' => 'Table lock', 'Duration' => '0.000007' 
    - 'Status' => 'init', 'Duration' => '0.000017' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000001' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000026' 
    - 'Status' => 'optimizing', 'Duration' => '0.000015' 
    - 'Status' => 'statistics', 'Duration' => '0.000027' 
    - 'Status' => 'preparing', 'Duration' => '0.000013' 
    - 'Status' => 'executing', 'Duration' => '0.000002' 
    - 'Status' => 'Sending data', 'Duration' => '1.048216' 
    - 'Status' => 'end', 'Duration' => '0.000003' 
    - 'Status' => 'query end', 'Duration' => '0.000001' 
    - 'Status' => 'freeing items', 'Duration' => '0.000122' 
    - 'Status' => 'logging slow query', 'Duration' => '0.000001' 
    - 'Status' => 'cleaning up', 'Duration' => '0.000003' 
- MYSQL functions from PHP unordered: 1.09 sec 
    - 'Status' => 'starting', 'Duration' => '0.000109' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000002' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000001' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000004' 
    - 'Status' => 'Opening tables', 'Duration' => '0.002101' 
    - 'Status' => 'System lock', 'Duration' => '0.000004' 
    - 'Status' => 'Table lock', 'Duration' => '0.000009' 
    - 'Status' => 'init', 'Duration' => '0.000032' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000003' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000057' 
    - 'Status' => 'optimizing', 'Duration' => '0.000033' 
    - 'Status' => 'statistics', 'Duration' => '0.000065' 
    - 'Status' => 'preparing', 'Duration' => '0.000032' 
    - 'Status' => 'executing', 'Duration' => '0.000005' 
    - 'Status' => 'Sending data', 'Duration' => '1.000079' 
    - 'Status' => 'end', 'Duration' => '0.000005' 
    - 'Status' => 'query end', 'Duration' => '0.000002' 
    - 'Status' => 'freeing items', 'Duration' => '0.000300' 
    - 'Status' => 'logging slow query', 'Duration' => '0.000001' 
    - 'Status' => 'cleaning up', 'Duration' => '0.000007' 
- MYSQL functions from PHP w/ ORDER BY: 1.09 sec 
    - 'Status' => 'starting', 'Duration' => '0.000148' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000001' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000001' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000001' 
    - 'Status' => 'Opening tables', 'Duration' => '0.000559' 
    - 'Status' => 'System lock', 'Duration' => '0.000002' 
    - 'Status' => 'Table lock', 'Duration' => '0.000006' 
    - 'Status' => 'init', 'Duration' => '0.000019' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000001' 
    - 'Status' => 'checking permissions', 'Duration' => '0.000030' 
    - 'Status' => 'optimizing', 'Duration' => '0.000018' 
    - 'Status' => 'statistics', 'Duration' => '0.000025' 
    - 'Status' => 'preparing', 'Duration' => '0.000015' 
    - 'Status' => 'Creating tmp table', 'Duration' => '0.001828' 
    - 'Status' => 'executing', 'Duration' => '0.000001' 
    - 'Status' => 'Copying to tmp table', 'Duration' => '0.958071' 
    - 'Status' => 'Sorting result', 'Duration' => '0.013502' 
    - 'Status' => 'Sending data', 'Duration' => '0.088148' 
    - 'Status' => 'end', 'Duration' => '0.000003' 
    - 'Status' => 'removing tmp table', 'Duration' => '0.002037' 
    - 'Status' => 'end', 'Duration' => '0.000003' 
    - 'Status' => 'query end', 'Duration' => '0.000001' 
    - 'Status' => 'freeing items', 'Duration' => '0.000112' 
    - 'Status' => 'logging slow query', 'Duration' => '0.000001' 
    - 'Status' => 'cleaning up', 'Duration' => '0.000004'

解释说：

在订购

|-id-|-select_type-|-table----|-type---|-possible_keys--------|-key-----------------|-key_len-|-ref-------------------------------------|-rows--|-Extra 
|-1--|-SIMPLE------|-s--------|-ALL----|-PRIMARY,search_index-|-NULL----------------|-NULL----|-NULL------------------------------------|-92166-|-Using temporary; Using filesort 
|-1--|-SIMPLE------|-tags-----|-eq_ref-|-PRIMARY--------------|-PRIMARY-------------|-426-----|-apiv2.s.item_id,apiv2.s.item_type,const-|-1-----|-Using where; Using index 
|-1--|-SIMPLE------|-featured-|-ref----|-type_position_index--|-type_position_index-|-62------|-const-----------------------------------|-3-----|-Using index

不需预定

|-id-|-select_type-|-table----|-type---|-possible_keys--------|-key-----------------|-key_len-|-ref-------------------------------------|-rows--|-Extra 
|-1--|-SIMPLE------|-s--------|-ALL----|-PRIMARY,search_index-|-NULL----------------|-NULL----|-NULL------------------------------------|-88346-|- 
|-1--|-SIMPLE------|-tags-----|-eq_ref-|-PRIMARY--------------|-PRIMARY-------------|-426-----|-apiv2.s.item_id,apiv2.s.item_type,const-|-1-----|-Using where; Using index 
|-1--|-SIMPLE------|-featured-|-ref----|-type_position_index--|-type_position_index-|-62------|-const-----------------------------------|-3-----|-Using index

表：search_all

CREATE TABLE `search_all` ( 
    `item_id` varchar(20) NOT NULL DEFAULT '', 
    `item_type` varchar(20) NOT NULL DEFAULT '', 
    `title` varchar(255) DEFAULT NULL, 
    `caption` text, 
    `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
    PRIMARY KEY (`item_id`,`item_type`), 
    UNIQUE KEY `search_index` (`item_id`,`item_type`,`date`), 
    KEY `date_index` (`date`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8; 


|-id-|-select_type-|-table------|-type-|-possible_keys-|-key--|-key_len-|-ref--|-rows--|-Extra 
|-1--|-SIMPLE------|-search_all-|-ALL--|-NULL----------|-NULL-|-NULL----|-NULL-|-74785-|-

表：标签

CREATE TABLE `tags` ( 
    `tag` varchar(100) NOT NULL DEFAULT '', 
    `updated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
    `item_id` varchar(20) NOT NULL DEFAULT '', 
    `item_type` varchar(20) NOT NULL DEFAULT '', 
    PRIMARY KEY (`item_id`,`item_type`,`tag`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8; 


|-id-|-select_type-|-table-|-type--|-possible_keys-|-key-----|-key_len-|-ref--|-rows---|-Extra 
|-1--|-SIMPLE------|-tags--|-index-|-NULL----------|-PRIMARY-|-426-----|-NULL-|-197400-|-Using index

表：功能

CREATE TABLE `featured` ( 
    `position` int(10) NOT NULL DEFAULT '0', 
    `item_type` varchar(20) NOT NULL DEFAULT '', 
    `item_id` varchar(20) NOT NULL DEFAULT '', 
    `feature_type` varchar(20) NOT NULL DEFAULT '', 
    PRIMARY KEY (`position`,`item_type`,`item_id`,`feature_type`), 
    KEY `type_position_index` (`feature_type`,`position`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8; 


|-id-|-select_type-|-table----|-type--|-possible_keys-|-key-----------------|-key_len-|-ref--|-rows-|-Extra 
|-1--|-SIMPLE------|-featured-|-index-|-NULL----------|-type_position_index-|-66------|-NULL-|-13---|-Using index

为什么PDO中的无序或PHP中的MSQL没有区别？有什么办法可以让它变得更快吗？

来源

2011-06-22 Ripptor

发布查询的表定义（包括索引）和（EXPLAIN）执行计划。 –

你真的能重现吗？ “发送数据”似乎在最后一个示例中消耗了太多时间。也许它只是一个“滞后”或缓存问题。 – KingCrunch

我相信时间是在配置文件中的每一步的开始时检查的，这意味着长时间的时间实际上是对前一步骤的错误评论，这会将所有手指指向“正在执行”的步骤 – Ripptor

除非您的订单是针对索引列的，并且优化器认为使用索引是一个好主意，则“ORDER BY”将导致需要大量时间和资源的任何大小的结果集。

PDO版本耗时较长的原因是您的脚本消耗的行数比SQLServer可以提供的速度慢，因此数据库正在等待您的程序。由于您使用的是一种解释型语言和一种对行结果进行大量操作的API，因此这只是预料之中。这种“发送数据”的延迟要比排序的开销大得多（0.75秒和1.04秒）。

请注意，缓慢的检索是由顺序复合。在无序SQL的情况下，行将在选择后立即发送。在有序选择的情况下，所有行都将被选中，然后在发送第一个结果行之前进行排序。

来源

2011-06-23 02:02:10

我有一个位置的索引，但由于大多数行没有加入精选，大多数不会有位置。我已经实现了PHP排序来跳过MYSQL端的排序，但是由于删除排序并没有加快速度，我没有任何改进。如果我可以加快无序的PDO，那么我认为它可以工作。你有没有建议呢？ – Ripptor

你可以请张贴表定义（字段，字段的类型等）？

我先上date表search_all上tag表tags添加一个简单的索引和

一个简单的索引。

来源

2011-06-23 15:21:04

已添加表格定义。在search_all中有一个日期索引，而tags表是一个三键（item_id，item_type，tag） – Ripptor

@Ripptor：索引'（tag）'与索引'（item_id，item_type，tag） –

PDO比mysql查询慢得多？

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