我正在试图找出为什么与我的笔记本电脑相比，查询在服务器上执行的时间太长。服务器和笔记本电脑都在WAMP 2.0上运行MySQL 5.1.36并且具有相同的数据库模式，因为我已从服务器数据库导出它并将其导入到笔记本电脑的数据库中。在服务器上执行0.031秒时，在笔记本电脑上执行需要82.447秒！
笔记本电脑规格
操作系统：Microsoft Windows 7 Professional， 处理器：Intel®Core™i7-4600M处理器（4M高速缓存，高达3.60 GHz）， 内存：8GB
服务器规格
操作系统：Microsoft Windows 2008 Standard SP2， 处理器：英特尔®至强®处理器X5570（8M高速缓存，2.93 GHz，6.40 GT / s英特尔®QPI）， 内存：4GB
以下是query is being executed和when not时服务器上CPU利用率的屏幕截图。请记住，服务器是在服务器场中运行的VM。
以下是查询，每个表的行数不超过1000行。
SELECT form.id AS `Reference No.`,
DATE_FORMAT(form.sbmt, '%d %b %Y') AS `Submission Date`,
DATE_FORMAT(form.sbmt, '%h:%i %p') AS `Submission Time`,
department.name AS `Department`,
section.name AS `Section`,
reporting_to_1.id AS `Reporting To 1 - System ID`,
reporting_to_1.name_ldap AS `Reporting To 1 - Name`,
reporting_to_1_department.name AS `Reporting To 1 - Department`,
CONVERT(IFNULL(reporting_to_2.id, '') USING utf8) AS `Reporting To 2 - System ID`,
IFNULL(reporting_to_2.name_ldap, '') AS `Reporting To 2 - Name`,
IFNULL(reporting_to_2_department.name, '') AS `Reporting To 2 - Department`,
form_type.des AS `Form Type`,
CONVERT(IF(form.subno = 0, '-', form.subno) USING utf8) AS `Subscriber No.`,
form.subname AS `Subscriber Name`,
form.incidentdate AS `Incident Date`,
form.rsndes AS `Reason`,
form.amount AS `Amount`,
form.des AS `Description`,
CONCAT('http://cns/attach/', attachment_1.path, '/', attachment_1.filename_generated) AS `Attachment - 1`,
CONCAT('http://cns/attach/', attachment_2.path, '/', attachment_2.filename_generated) AS `Attachment - 2`,
IFNULL(info.name, '') AS `Agent Info - Name`,
CONVERT(IFNULL(info.emp_id, '') USING utf8) AS `Agent Info - ID`,
IFNULL(info.tabs, '') AS `Agent Info - TABS`,
IFNULL(info.type, '') AS `Agent Info - Type`,
CONVERT(IFNULL(info_teamleader.id, '') USING utf8) AS `Agent Info - Team Leader - System ID`,
IFNULL(info_teamleader.name_ldap, '') AS `Agent Info - Team Leader - Name`,
creator.id AS `Created By - System ID`,
creator.name AS `Created By - Name`,
CONVERT(IFNULL(authorizing_teamleader_user.id, '') USING utf8) AS `Processed By - Team Leader - System ID`,
IFNULL(authorizing_teamleader_user.name_ldap, '') AS `Processed By - Team Leader - Name`,
CONVERT(IFNULL(authorizing_teamleader_user.emp_id, '') USING utf8) AS `Processed By - Team Leader - Employee ID`,
CONVERT(IFNULL(DATE_FORMAT(authorizing_teamleader.datetime, '%d %b %Y'), '') USING utf8) AS `Processed On - Team Leader - Date`,
CONVERT(IFNULL(DATE_FORMAT(authorizing_teamleader.datetime, '%h:%i %p'), '') USING utf8) AS `Processed On - Team Leader - Time`,
CONVERT(IFNULL(authorizing_manager_user.id, '') USING utf8) AS `Processed By - Manager - System ID`,
IFNULL(authorizing_manager_user.name_ldap, '') AS `Processed By - Manager - Name`,
CONVERT(IFNULL(authorizing_manager_user.emp_id, '') USING utf8) AS `Processed By - Manager - Employee ID`,
CONVERT(IFNULL(DATE_FORMAT(authorizing_manager.datetime, '%d %b %Y'), '') USING utf8) AS `Processed On - Manager - Date`,
CONVERT(IFNULL(DATE_FORMAT(authorizing_manager.datetime, '%h:%i %p'), '') USING utf8) AS `Processed On - Manager - Time`,
CONVERT(IFNULL(authorizing_director_user.id, '') USING utf8) AS `Processed By - Director - System ID`,
IFNULL(authorizing_director_user.name_ldap, '') AS `Processed By - Director - Name`,
CONVERT(IFNULL(authorizing_director_user.emp_id, '') USING utf8) AS `Processed By - Director - Employee ID`,
CONVERT(IFNULL(DATE_FORMAT(authorizing_director.datetime, '%d %b %Y'), '') USING utf8) AS `Processed On - Director - Date`,
CONVERT(IFNULL(DATE_FORMAT(authorizing_director.datetime, '%h:%i %p'), '') USING utf8) AS `Processed On - Director - Time`,
status.des AS `Status`,
CONVERT(IF(status.des = 'Pending', '', status_by.id) USING utf8) AS `Status By - System ID`,
IFNULL(status_by.name_ldap, '') AS `Status By - Name`,
CONVERT(IFNULL(status_by.emp_id, '') USING utf8) AS `Status By - Employee ID`,
IFNULL(status_by_role.des, '') AS `Status By - Position`,
CONVERT(IFNULL(DATE_FORMAT(form.statuson, '%d %b %Y'), '') USING utf8) AS `Status On - Date`,
CONVERT(IFNULL(DATE_FORMAT(form.statuson, '%h:%i %p'), '') USING utf8) AS `Status On - Time`,
CONCAT('http://cns/pdf/', form.pdf) AS `PDF`
FROM cns_form AS form
JOIN cns_departments AS department
ON form.deptid = department.id
JOIN cns_sections AS section
ON form.sectid = section.id
JOIN (cns_users AS reporting_to_1,
cns_departments AS reporting_to_1_department)
ON reporting_to_1.id = form.rprtid1
AND reporting_to_1.dept_id = reporting_to_1_department.id
LEFT JOIN (cns_users AS reporting_to_2,
cns_departments AS reporting_to_2_department)
ON reporting_to_2.id = form.rprtid2
AND reporting_to_2.dept_id = reporting_to_2_department.id
LEFT JOIN cns_form_attachments AS attachment_1
ON form.id = attachment_1.form_id
AND attachment_1.id = (SELECT MIN(id)
FROM cns_form_attachments
WHERE form_id = form.id)
LEFT JOIN cns_form_attachments AS attachment_2
ON form.id = attachment_2.form_id
AND attachment_2.id = (SELECT MAX(id)
FROM cns_form_attachments
WHERE form_id = form.id)
JOIN cns_status AS status
ON form.status = status.id
JOIN cns_form_type AS form_type
ON form.waivetype = form_type.id
LEFT JOIN (cns_form_infos AS info,
cns_users AS info_teamleader)
ON form.id = info.form_id
AND info_teamleader.id = info.teamleaderid
JOIN cns_users AS creator
ON creator.id = form.empid
LEFT JOIN (cns_form_authorizers AS authorizing_teamleader,
cns_users AS authorizing_teamleader_user)
ON authorizing_teamleader.form = form.id
AND authorizing_teamleader.role = 't'
AND authorizing_teamleader_user.id = authorizing_teamleader.`from`
LEFT JOIN (cns_form_authorizers AS authorizing_manager,
cns_users AS authorizing_manager_user)
ON authorizing_manager.form = form.id
AND authorizing_manager.role = 'm'
AND authorizing_manager_user.id = authorizing_manager.`from`
LEFT JOIN (cns_form_authorizers AS authorizing_director,
cns_users AS authorizing_director_user)
ON authorizing_director.form = form.id
AND authorizing_director.role = 'd'
AND authorizing_director_user.id = authorizing_director.`from`
LEFT JOIN (cns_users AS status_by,
cns_roles AS status_by_role)
ON status_by.id = form.statusby
AND status_by.role = status_by_role.id
WHERE status.des != 'Pending'
ORDER BY form.id DESC
对上述查询
进行EXPLAIN
+----+--------------------+-----------------------------+--------+------------------------------------+----------------+---------+--------------------------------------+------+----------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+--------------------+-----------------------------+--------+------------------------------------+----------------+---------+--------------------------------------+------+----------------------------------------------------+
| 1 | PRIMARY | form | ALL | empid,rprtid1,deptid,sectid,status | NULL | NULL | NULL | 779 | Using temporary; Using filesort |
| 1 | PRIMARY | authorizing_teamleader | ref | from,role | role | 1 | const | 0 | Using where |
| 1 | PRIMARY | authorizing_teamleader_user | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.authorizing_teamleader.from | 1 | NULL |
| 1 | PRIMARY | authorizing_manager | ref | from,role | role | 1 | const | 0 | Using where |
| 1 | PRIMARY | authorizing_manager_user | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.authorizing_manager.from | 1 | NULL |
| 1 | PRIMARY | status | ALL | PRIMARY,des | NULL | NULL | NULL | 3 | Using where; Using join buffer (Block Nested Loop) |
| 1 | PRIMARY | reporting_to_1 | eq_ref | PRIMARY,dept_id | PRIMARY | 4 | wfs-test.form.rprtid1 | 1 | Using where |
| 1 | PRIMARY | reporting_to_2 | eq_ref | PRIMARY,dept_id | PRIMARY | 4 | wfs-test.form.rprtid2 | 1 | NULL |
| 1 | PRIMARY | reporting_to_2_department | ALL | PRIMARY | NULL | NULL | NULL | 9 | Using where |
| 1 | PRIMARY | info | eq_ref | form_id_UNIQUE | form_id_UNIQUE | 4 | wfs-test.form.id | 1 | NULL |
| 1 | PRIMARY | info_teamleader | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.info.teamleaderid | 1 | NULL |
| 1 | PRIMARY | creator | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.form.empid | 1 | NULL |
| 1 | PRIMARY | attachment_1 | ref | PRIMARY,form_id | form_id | 4 | wfs-test.form.id | 1 | Using where |
| 1 | PRIMARY | attachment_2 | ref | PRIMARY,form_id | form_id | 4 | wfs-test.form.id | 1 | Using where |
| 1 | PRIMARY | authorizing_director | ref | from,role | role | 1 | const | 0 | Using where |
| 1 | PRIMARY | authorizing_director_user | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.authorizing_director.from | 1 | NULL |
| 1 | PRIMARY | status_by | eq_ref | PRIMARY,role | PRIMARY | 4 | wfs-test.form.statusby | 1 | NULL |
| 1 | PRIMARY | status_by_role | ALL | PRIMARY | NULL | NULL | NULL | 8 | Using where |
| 1 | PRIMARY | department | ALL | PRIMARY | NULL | NULL | NULL | 9 | Using where; Using join buffer (Block Nested Loop) |
| 1 | PRIMARY | reporting_to_1_department | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.reporting_to_1.dept_id | 1 | NULL |
| 1 | PRIMARY | section | eq_ref | PRIMARY | PRIMARY | 4 | wfs-test.form.sectid | 1 | NULL |
| 3 | DEPENDENT SUBQUERY | cns_form_attachments | ref | form_id | form_id | 4 | wfs-test.form.id | 1 | NULL |
| 2 | DEPENDENT SUBQUERY | cns_form_attachments | ref | form_id | form_id | 4 | wfs-test.form.id | 1 | NULL |
+----+--------------------+-----------------------------+--------+------------------------------------+----------------+---------+--------------------------------------+------+----------------------------------------------------+