Oracle SQL tuning 數據庫優化步驟圖文教程

 　　SQL Turning 是Quest公司出品的Quest Central軟件中的一個工具。Quest Central是一款集成化、圖形化、跨平台的數據庫管理解決方案，可以同時管理 Oracle、DB2 和 SQL server 數據庫。

　　一、SQL Tuning for SQL Server簡介

　　SQL語句的優化對發揮數據庫的最佳性能非常關鍵。然而不幸的是，應用優化通常由於時間和資源的因素而被忽略。SQL Tuning (SQL優化)模塊可以對比和評測特定應用中SQL語句的運行性能，提出智能化的優化建議，幫助用戶改善應用的響應時間。SQL優化模塊具有非介入式SQL采集、自動優化和專家建議等功能，全面改善SQL優化工作。

　　二、SQL Tuning for SQL Server的使用

　　1、打開Quest Database Management Solutions彈出窗口如圖1所示

　　圖1

　　2、在紅色標記處打開SQL Tuning 優化SQL

　　(1)建立連接。

　　在Quest Central主界面上的“Database”樹上選擇“SQL Server”，然後在下方出現的“Tools”框中選擇“SQL Tuning”選項，打開“Lanch SQL Tuning for SQL Server Connections”對話框(圖2、圖3)。我們在這裡建立數據庫服務器的連接，以後的分析工作都會在它上面完成。

　　圖2 “建立連接”對話框

　　圖3

　　雙擊“New Connection”圖標，在彈出窗口中輸入數據庫的信息，單擊“OK”，然後單擊“Connect”即可。

　　(2)分析原始SQL語句 ，在單擊“Connect”後將彈出一個新窗口，如圖4

　　圖4

　　在打開窗口的“Oriangal SQL”文本框內輸入需要分析的原始SQL語句，紅色標記處選擇對應的數據庫名，SQL語句代碼如下：

　　圖5 分析原始SQL語句

　　原始SQL語句

　　然後點擊工具欄上的“Execute”按鈕，執行原始的SQL語句，SQL Tuning會自動分析SQL的執行計劃，並把分析結果顯示到界面上(圖5)。

　　(3)優化SQL。

　　現在我們點擊工具欄上的“Optimize Statement”按鈕,讓SQL Tuning開始優化SQL，完成後，可以看到SQL Tuning產生了19條與原始SQL等價的優化方案(圖6)。

　　圖6 SQL優化方案

　　(4)獲得最優SQL。

　　接下來，我們來執行上面產生的優化方案，以選出性能最佳的等效SQL語句。在列表中選擇需要執行的優化方案(默認已全部選中)，然後點擊工具欄上的“Execute”按鈕旁邊的下拉菜單，選擇“Execute Selected”。等到所有SQL運行完成後,點擊界面左方的“Tuning Resolution”按鈕，

　　可以看到最優的SQL已經出來啦，運行時間竟然可以提高21%!(圖7)

　　圖7 “Tuning Resolution”界面

　　最優的SQL語句如下：

　　5)學習書寫專家級的SQL語句 。

　　優化後的SQL語句

　　SELECT dbo.Person_BasicInfo.*,

　　dbo.Graduater_GraduaterRegist.RegistNO AS RegistNO,

　　dbo.Graduater_GraduaterRegist.RegistTime AS BaoDaoTime,

　　dbo.Graduater_GraduaterRegist.RegistMan AS RegistMan,

　　dbo.Graduater_Business.ComeFrom AS ComeFrom,

　　dbo.Graduater_Business.Code AS Code,

　　dbo.Graduater_Business.Status AS Status,

　　dbo.Graduater_Business.ApproveResult AS ApproveResult,

　　dbo.Graduater_Business.NewCorp AS NewCorp,

　　dbo.Graduater_Business.CommendNumber AS CommendNumber,

　　dbo.Graduater_Business.EmployStatus AS EmployStatus,

　　dbo.Graduater_Business.NewCommendTime AS NewCommendTime,

　　dbo.Graduater_Business.GetSource AS GetSource,

　　dbo.Graduater_Business.EmployTime AS EmployTime,

　　dbo.Graduater_Business.Job AS Job,

　　dbo.Graduater_Business.FillMan AS FillMan,

　　dbo.Graduater_Business.FillTime AS FillTime,

　　dbo.Graduater_Business.IsCommendOK AS IsCommendOK,

　　dbo.Graduater_Business.ApproveUser AS ApproveUser,

　　dbo.Graduater_Business.ApproveTime AS ApproveTime,

　　dbo.Graduater_Business.RegistTime AS RegistTime,

　　dbo.Graduater_Business.EmployCorp AS EmployCorp,

　　dbo.Graduater_Business.JobRemark AS JobRemark,

　　CASE WHEN dbo.Graduater_Business.ComeFrom = 'WS' THEN '網上登記'

　　WHEN dbo.Graduater_Business.ComeFrom = 'HP' THEN '華普大廈'

　　WHEN dbo.Graduater_Business.ComeFrom = 'JD' THEN '精典大廈'

　　WHEN dbo.Graduater_Business.ComeFrom = 'MC' THEN '賽馬場'

　　WHEN ComeFrom = 'ZX' THEN '高指中心' END AS ComeFromName,

　　dbo.Person_Contact.Address AS Address,

　　dbo.Person_Contact.Zip AS Zip,

　　dbo.Person_Contact.Telephone AS Telephone,

　　dbo.Person_Contact.Mobile AS Mobile,

　　dbo.Person_Contact.Email AS Email,

　　dbo.Person_Contact.IM AS IM,

　　dbo.Person_Skill.ForeignLanguage AS ForeignLanguage,

　　dbo.Person_Skill.ForeignLanguageLevel AS ForeignLanguageLevel,

　　dbo.Person_Skill.CantoneseLevel AS CantoneseLevel,

　　dbo.Person_Skill.MandarinLevel AS MandarinLevel,

　　dbo.Person_Skill.Language AS Language,

　　dbo.Person_Skill.TechnicalTitle AS TechnicalTitle,

　　dbo.Person_Skill.ComputerLevel AS ComputerLevel,

　　dbo.Person_EmployPurpose.JobType AS JobType,

　　dbo.Person_EmployPurpose.Vocation AS Vocation,

　　dbo.Person_EmployPurpose.JobPlace AS JobPlace,

　　dbo.Person_EmployPurpose.Salary AS Salary,

　　dbo.Person_EmployPurpose.OnJobDate AS OnJobDate,

　　dbo.Person_EmployPurpose.CorpType AS CorpType,

　　dbo.Person_EmployPurpose.Job AS RequireJob,

　　YEAR(GETDATE()) - YEAR(dbo.Person_BasicInfo.Birthday) AS Age,

　　dbo.Graduater_Business.EmployType AS EmployType,

　　dbo.Graduater_Business.EmployTypeCode AS EmployTypeCode,

　　dbo.Graduater_Business.EmployCorpType AS EmployCorpType,

　　CASE WHEN dbo.Graduater_Business.PrintStatus = '已打印' THEN '已打印'

　　ELSE '未打印' END AS PrintStatus,

　　dbo.Graduater_Business.PrintTime AS PrintTime,

　　CASE WHEN dbo.Graduater_Business.EmployStatus = '是' THEN '已就業'

　　ELSE '未就業' END AS EmployStatusView

　　FROM dbo.Person_BasicInfo

　　INNER JOIN dbo.Graduater_Business

　　ON dbo.Person_BasicInfo.PersonID = dbo.Graduater_Business.PersonID

　　LEFT OUTER JOIN dbo.Graduater_GraduaterRegist

　　ON dbo.Graduater_Business.GradBusinessID = dbo.Graduater_GraduaterRegist.GraduaterGUID

　　INNER JOIN dbo.Person_Contact

　　ON dbo.Person_BasicInfo.PersonID = dbo.Person_Contact.PersonID

　　INNER JOIN dbo.Person_Skill

　　ON dbo.Person_BasicInfo.PersonID = dbo.Person_Skill.PersonID

　　INNER JOIN dbo.Person_EmployPurpose

　　ON dbo.Person_BasicInfo.PersonID = dbo.Person_EmployPurpose.PersonID

　　OPTION (FORCE ORDER)

　　(

　　通過上面的步驟，我們已經可以實現自動優化SQL語句，但更重要的是，我們還可以學習如何書寫這樣高性能的SQL語句。點擊界面左方的