Mysql 难以解释是什么使我的查询如此缓慢
我有一个查询,在MySQL 5.6服务器上需要15秒才能得到350个结果,我无法诊断原因,我对数据库优化还是很陌生。U EXPLAIN visual确实显示了一些非唯一的键查找,但每个键只显示一个1行查找 我无法解释的表格解释,我希望其他人也能解释 我已经尝试将结束Mysql 难以解释是什么使我的查询如此缓慢,mysql,Mysql,我有一个查询,在MySQL 5.6服务器上需要15秒才能得到350个结果,我无法诊断原因,我对数据库优化还是很陌生。U EXPLAIN visual确实显示了一些非唯一的键查找,但每个键只显示一个1行查找 我无法解释的表格解释,我希望其他人也能解释 我已经尝试将结束LIMIT=350切换到100,10,查询运行所需的时间完全相同,大约为15秒 我已经尝试过禁用视图,但是除了使重新创建此查询变得困难之外,它并没有提高性能 也许相关的,在MySQL数据库中的其他EXPLAIN语句中,我看到了一个在它
LIMIT=350
切换到100,10,查询运行所需的时间完全相同,大约为15秒
我已经尝试过禁用视图,但是除了使重新创建此查询变得困难之外,它并没有提高性能
也许相关的,在MySQL数据库中的其他EXPLAIN语句中,我看到了一个在它旁边用Materialized引用的视图,但它没有出现在这个查询中使用的三个视图的旁边,事实上,我甚至没有看到被引用的视图,而只看到它们引用的表。这是一个因素吗
我上一次尝试是用特定的列替换最后选择的列,该列是一个listlineitems.*
,因为我已经阅读了可以提高速度的内容,这只是更好的练习,但我感觉这不会显著改善这种情况
以下是问题-
SELECT
0 AS 'Check',
DATE_FORMAT(`listlineitems`.`dateEntered`,
'%Y-%m-%d') AS 'Date Entered',
`listlineitems`.`itemId` AS 'parentTableIdx',
`listlineitems`.`parentProjectId` AS 'parentProjectIdx',
`listlineitems`.`idx` AS 'ID',
IF(`listlineitems`.`active` = 1,
'Active',
'Inactive') AS 'Active/Inactive',
CONCAT(`listUsers`.`FirstName`,
' ',
`listUsers`.`LastName`) AS 'Employee',
CASE `listlineitems`.`type`
WHEN 1 THEN 'Time Entry'
WHEN 2 THEN 'Expense Entry'
END AS 'Type',
`listcustomers`.`name` AS 'Customer',
`listlocations`.`name` AS 'Location',
`listareas`.`name` AS 'Area',
`listassets`.`name` AS 'Asset',
`listprojects`.`name` AS 'Project',
`listprojects`.`number` 'Project #',
`listprojects`.`autoassign` 'autoassign',
`listactivities`.`name` AS 'Activity',
(CASE `listlineitems`.`type`
WHEN 1 THEN `listlineitems`.`qty`
WHEN 2 THEN `listlineitems`.`qty`
END) AS 'Quantity',
`listlineitems`.`taxable` AS 'Taxable',
`listlineitems`.`totalAmount` - `listlineitems`.`taxAmount` AS 'Pre-Tax Amount',
`listlineitems`.`taxAmount` AS 'Tax Amount',
`listlineitems`.`totalAmount` AS 'Total Amount',
`listCustomers`.`idx` AS 'parentCustomerIdx',
`listLocations`.`idx` AS 'parentLocationIdx',
`listAreas`.`idx` AS 'parentAreaIdx',
`listAssets`.`idx` AS 'parentAssetIdx',
CONCAT(`listcustomers`.`name`,
'/',
`listlocations`.`name`,
'/',
`listareas`.`name`,
'/',
`listassets`.`name`,
'/',
`listprojects`.`name`) AS 'Path',
IF(`listlineitems`.`customerViewable` = 1,
'Yes',
'No') AS 'Cust. Viewable',
(CASE
WHEN `listlineitems`.`type` = 2 THEN `listexpenseentry`.`TotalCostToPSI` - `listexpenseentry`.`TaxCostToPSI`
ELSE `listlineitems`.`totalAmount` - `listlineitems`.`taxAmount`
END) AS 'preTaxCostPSI',
(CASE
WHEN `listlineitems`.`type` = 2 THEN `listexpenseentry`.`TaxCostToPSI`
ELSE `listlineitems`.`taxAmount`
END) AS 'taxCostPSI',
(CASE
WHEN `listlineitems`.`type` = 2 THEN `listexpenseentry`.`TotalCostToPSI`
ELSE `listlineitems`.`totalAmount`
END) AS 'totalCostPSI',
view_solinx2.lastAltered AS 'lastalteredSO',
view_polinx2.lastAlteredPO AS 'lastalteredPO',
view_invlinx2.lastAlteredInv AS 'lastalteredInv',
view_solinx2.lastAlteredAfterConfirmation AS 'lastAlteredAfterConfirmation',
view_solinx2.roleIdSO AS 'roleIdSO',
view_polinx2.roleIdPO AS 'roleIdPO',
view_polinx2.userIdPO AS 'userIdPO',
view_polinx2.lastAlteredafterConfirmation AS 'lastAlteredAfterConfirmationPO',
view_invlinx2.roleIdInv AS 'roleIdInv',
view_invlinx2.userIdInv AS 'userIdInv',
view_invlinx2.lastAlteredafterConfirmation AS 'lastAlteredAfterConfirmationInv',
view_solinx2.roleId AS 'roleId',
view_solinx2.userId AS 'userId',
view_solinx2.soId AS 'SOId',
view_solinx2.autoassignSO AS 'autoassignSO',
IF(view_solinx2.notNeeded = 1,
'Not Needed',
view_solinx2.number) AS 'SOname',
view_solinx2.dateEntered AS 'SoDate',
view_solinx2.totalSOAmount AS 'SoTotal',
view_invlinx2.invId AS 'InvId',
IF(view_solinx2.notNeeded = 1,
'------',
view_invlinx2.`number`) AS 'InvName',
view_invlinx2.dateEntered AS 'InvDate',
view_invlinx2.amount AS 'InvTotal',
view_polinx2.poId AS 'POId',
IF(view_solinx2.notNeeded = 1,
'------',
view_polinx2.`number`) AS 'POName',
view_polinx2.dateEntered AS 'PODate',
view_polinx2.amount AS 'POTotal',
(SELECT
listsalesorders.number
FROM
listsalesorders
WHERE
listsalesorders.idx = autoassign) AS 'test',
`listlineitems`.*
FROM
`listlineitems`
LEFT JOIN
`listUsers` ON `listlineitems`.`individualId` = `listUsers`.`idx`
LEFT JOIN
`listprojects` ON `listlineitems`.`parentProjectId` = `listprojects`.`idx`
LEFT JOIN
`listassets` ON `listlineitems`.`parentAssetId` = `listassets`.`idx`
LEFT JOIN
`listareas` ON `listlineitems`.`parentAreaId` = `listareas`.`idx`
LEFT JOIN
`listlocations` ON `listlineitems`.`parentLocationId` = `listlocations`.`idx`
LEFT JOIN
`listcustomers` ON `listlineitems`.`parentCustomerId` = `listcustomers`.`idx`
LEFT JOIN
`listactivities` ON `listactivities`.`idx` = `listlineitems`.`activityCode`
LEFT JOIN
`listexpenseentry` ON (`listexpenseentry`.`idx` = `listlineitems`.`itemId`
AND `listlineitems`.`type` = 2)
LEFT JOIN
view_solinx2 ON view_solinx2.idx = listlineitems.idx
LEFT JOIN
view_polinx2 ON view_polinx2.idx = listlineitems.idx
LEFT JOIN
view_invlinx2 ON view_invlinx2.idx = listlineitems.idx
GROUP BY `listlineitems`.`idx`
ORDER BY `listlineitems`.`dateEntered` DESC
LIMIT 10;
我不知道我还能做些什么来改进这一点,任何建议都非常感谢。您正在从listlineitems表(100+K记录)中选择所有内容,加入许多表,然后按idx分组,然后抛出大多数结果 你可以:
- 尝试将唯一索引(dateEntered,idx)添加到listlineitems
- 如果可以接受,请尝试按输入的日期限制listlineitems(其中输入的日期>日期(NOW(),间隔30天))。必须为输入的日期编制索引
- 尝试将selectfromlineitems+grouping+limit放入子查询,这样MySQL将只对子查询返回的这10行进行连接
- 将依赖子查询(listsalesorders)转换为左联接