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MySQL LIMIT optimization issue

开发者 https://www.devze.com 2023-03-23 20:35 出处:网络
I have the following MySQL query that I\'m looking to make the LIMIT faster as it\'s runningVERY slow.SQL_CALC_FOUND_ROWS equals about 114000 rows.

I have the following MySQL query that I'm looking to make the LIMIT faster as it's running VERY slow. SQL_CALC_FOUND_ROWS equals about 114000 rows.

SELECT SQL_CALC_FOUND_ROWS PStD.ProductID FROM ProductStoreDef PStD
    JOIN ProductSummary PS ON PStD.ProductID = PS.ProductID 
    JOIN MasterVendor MV ON MV.VendorID = PStD.MasterVendorID 
WHERE 
    PStD.SKUStatus = 'A' AND 
    MV.isActive = 1 AND 
    PStD.MasterCategoryID = 66 AND 
    PStD.CustomerPrice > 0
ORDER BY PStD.VendorName, PS.VendorPartNumber 
LIMIT 100000,50

The following is the EXPLAIN results

+----+-------------+-------+--------+-------------------------------------------------------------------------------------------------+-----------------+---------+-------------------------+------+---------------开发者_开发知识库-------------------------------+
| id | select_type | table | type   | possible_keys                                                                                   | key             | key_len | ref                     | rows | Extra                                        |
+----+-------------+-------+--------+-------------------------------------------------------------------------------------------------+-----------------+---------+-------------------------+------+----------------------------------------------+
|  1 | SIMPLE      | MV    | ALL    | PRIMARY,isActive,VendorID                                                                       | NULL            | NULL    | NULL                    | 2126 | Using where; Using temporary; Using filesort | 
|  1 | SIMPLE      | PStD  | ref    | PRIMARY,MasterVendorID,MasterCategoryID,SKUStatus,CustomerPrice,MasterVendCatID,ProdStoreStatus | MasterVendCatID | 8       | ecomm.MV.VendorID,const |   94 | Using where                                  | 
|  1 | SIMPLE      | PS    | eq_ref | PRIMARY                                                                                         | PRIMARY         | 4       | ecomm.PStD.ProductID    |    1 |                                              | 
+----+-------------+-------+--------+-------------------------------------------------------------------------------------------------+-----------------+---------+-------------------------+------+----------------------------------------------+

Any advice would be appreciated.

Update: Solved this issue by creating a separate table that pre-calculates the sort order making the site run about 500x to 1000x faster.


Seems like the problem is sorting. In this case you may try to create these indexes, but I cannot guarantee anything:

ALTER TABLE `ProductStoreDef` ADD INDEX `ProductStoreDef_CIndex` (
    `ProductID` ASC, `MasterVendorID` ASC, `MasterCategoryID` ASC, 
    `SKUStatus` ASC, `CustomerPrice` ASC, `VendorName` ASC
);    
ALTER TABLE `ProductSummary` ADD INDEX `ProductSummary_CIndex` (
    `ProductID` ASC, `VendorPartNumber` ASC
);    
ALTER TABLE `MasterVendor` ADD INDEX `MasterVendor_CIndex` (
    `VendorID` ASC, `isActive` ASC
);
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