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MySQL "OR MATCH" hangs (very slow) on multiple tables

开发者 https://www.devze.com 2022-12-31 02:36 出处:网络
After learning how to do MySQL Full-Text search, the recommended solution for multiple tables was OR MATCH and then do the other database call. You can see that in my query below.

After learning how to do MySQL Full-Text search, the recommended solution for multiple tables was OR MATCH and then do the other database call. You can see that in my query below.

When I do this, it just gets stuck in a "busy" state, and I can't access the MySQL database.

SELECT 
 a.`product_id`, a.`name`, a.`slug`, a.`description`, b.`list_price`, b.`price`, c.`image`, c.`swatch`, e.`name` AS industry, 
 MATCH( a.`name`, a.`sku`, a.`description` ) AGAINST ( '%s' IN BOOLEAN MODE )     AS relevance 
FROM 
 `products` AS a LEFT JOIN `website_products` AS b 
  ON (a.`product_id` = b.`product_id`) 
 LEFT JOIN ( SELECT `product_id`, `image`, `swatch` FROM `product_images` WHERE `sequence` = 0) AS c 
  ON (a.`product_id` = c.`product_id`) 
 LEFT JOIN `brands` AS d 
  ON (a.`brand_id` = d.`brand_id`) 
 INNER JOIN `industries` AS e ON (a.`industry_id` = e.`industry_id`) 
WHERE 
 b.`website_id` = %d
 AND b.`status` = %d
 AND b.`active` = %d 
 AND MATCH( a.`name`, a.`sku`, a.`description` ) AGAINST ( '%s' IN BOOLEAN MODE ) 
  OR MATCH ( d.`name` ) AGAINST ( '%s' IN BOOLEAN MODE )
GROUP BY a.`product_开发者_开发技巧id` 
ORDER BY relevance DESC 
LIMIT 0, 9 

Any help would be greatly appreciated.


EDIT

All the tables involved are MyISAM, utf8_general_ci.

Here's the EXPLAIN SELECT statement:

id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a ALL NULL NULL NULL NULL 16076 Using temporary; Using filesort
1 PRIMARY b ref product_id product_id 4 database.a.product_id 2  
1 PRIMARY e eq_ref PRIMARY PRIMARY 4 database.a.industry_id 1  
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 23261  
1 PRIMARY d eq_ref PRIMARY PRIMARY 4 database.a.brand_id 1 Using where
2 DERIVED product_images ALL NULL NULL NULL NULL 25933 Using where

I don't know how to make that look neater -- sorry about that


UPDATE

it returns the query after 196 seconds (I think correctly). The query without multiple tables takes about .56 seconds (which I know is really slow, we plan on changing to solr or sphinx soon), but 196 seconds??

If we could add a number to the relevance if it was in the brand name ( d.name ), that would also work


I found 2 things slowing down my query drastically and fixed them.

To answer the first problem, it needed parentheses around the entire "MATCH AGAINST OR MATCH AGAINST":

WHERE 
    b.`website_id` = %d
    AND b.`status` = %d
    AND b.`active` = %d 
    AND ( 
        MATCH( a.`name`, a.`sku`, a.`description` ) AGAINST ( '%s' IN BOOLEAN MODE ) 
        OR MATCH ( d.`name` ) AGAINST ( '%s' IN BOOLEAN MODE )
    )

I didn't understand how to use EXPLAIN SELECT, but it helped quite a bit, so thank you! This reduced that first number 16076 rows to 143. I then noticed the other two with over 23 and 25 thousand rows. That was cause from this line:

LEFT JOIN ( SELECT `product_id`, `image`, `swatch` FROM `product_images` WHERE `sequence` = 0) AS c 
    ON (a.`product_id` = c.`product_id`)

There was a reason I was doing this in the first place, which then changed. When I changed it, I didn't realize I could do a normal LEFT JOIN:

LEFT JOIN `product_images` AS c 
    ON (a.`product_id` = c.`product_id`)

This makes my final query like this: (and MUCH faster went from the 196 seconds to 0.0084 or so)

SELECT 
    a.`product_id`, a.`name`, a.`slug`, a.`description`, b.`list_price`, b.`price`, 
    c.`image`, c.`swatch`, e.`name` AS industry, 
    MATCH( a.`name`, a.`sku`, a.`description` ) AGAINST ( '%s' IN BOOLEAN MODE ) AS relevance 
FROM 
    `products` AS a LEFT JOIN `website_products` AS b 
        ON (a.`product_id` = b.`product_id`) 
    LEFT JOIN `product_images` AS c 
        ON (a.`product_id` = c.`product_id`) 
    LEFT JOIN `brands` AS d 
        ON (a.`brand_id` = d.`brand_id`) 
    INNER JOIN `industries` AS e 
        ON (a.`industry_id` = e.`industry_id`) 
WHERE 
    b.`website_id` = %d
    AND b.`status` = %d
    AND b.`active` = %d
    AND c.`sequence` = %d
    AND ( 
        MATCH( a.`name`, a.`sku`, a.`description` ) AGAINST ( '%s' IN BOOLEAN MODE ) 
        OR MATCH( d.`name` ) AGAINST( '%s' IN BOOLEAN MODE ) 
    )
GROUP BY a.`product_id` 
ORDER BY relevance DESC 
LIMIT 0, 9

Oh, and even before I was doing a full text search with multiple tables, it was taking about 1/2 a second. This is much improved.

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