Question

我目前正在使用LEFT JOIN对2个表执行查找。交易时间非常缓慢，通常约为10秒。请查看下面的表格/查询/个人资料信息。

表＃1（14k行）：

CREATE TABLE `price` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`PRICE_ID` varchar(255) COLLATE latin1_general_ci DEFAULT NULL,
`TYPE` varchar(255) COLLATE latin1_general_ci DEFAULT NULL,
`PRICING_REF` varchar(255) COLLATE latin1_general_ci DEFAULT NULL,
`STOCK_CODE` varchar(255) COLLATE latin1_general_ci DEFAULT NULL,
`CALC_METHOD` bigint(20) DEFAULT NULL,
`CALC_VALUE` double DEFAULT NULL,
`STORED_PRICE` double DEFAULT NULL,
`ROUNDER_METHOD` tinyint(4) DEFAULT NULL,
`ROUNDER_DIRECTION` tinyint(4) DEFAULT NULL,
`ROUNDER_MULTIPLE_OF` double DEFAULT NULL,
`ROUNDER_ADJUSTMENT` double DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;

表＃2（18k行）：

CREATE TABLE `stock` (
 `id` bigint(20) NOT NULL AUTO_INCREMENT,
 `STOCK_CODE` varchar(255) COLLATE latin1_general_ci DEFAULT NULL,
 `DESCRIPTION` varchar(255) COLLATE latin1_general_ci DEFAULT NULL,
 `SALES_PRICE` double DEFAULT NULL,
 `LAST_PURCHASE_PRICE` double DEFAULT NULL,
 `QTY_IN_STOCK` double DEFAULT NULL,
 `QTY_ON_ORDER` double DEFAULT NULL,
 `LAST_SALE_DATE` date DEFAULT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;

查询：

SELECT stock.*,price.stored_price,price.pricing_ref 
FROM stock 
    LEFT JOIN price ON stock.stock_code = price.stock_code 
    AND price.pricing_ref = '2HWE001' 
LIMIT 0,10

分析器：

Detailed profile

Order   StateDocumentation  Time
1   Starting    102 µs
2   Checking Permissions    5 µs
3   Checking Permissions    3 µs
4   Opening Tables  36 µs
5   Init    35 µs
6   System Lock 11 µs
7   Optimizing  6 µs
8   Statistics  24 µs
9   Preparing   30 µs
10  Executing   2 µs
11  Sending Data    9.8 s
12  End 19 µs
13  Query End   8 µs
14  Closing Tables  16 µs
15  Freeing Items   67 µs
16  Cleaning Up 16 µs

我在MySQL中启用了query_cache，但它几乎没有带来任何好处。任何人都可以对此有所了解吗？

MySQL发送数据速度慢 - LEFT JOIN查询

0 个答案: