如何提高這個sql查詢性能？

Question

比方說，我有兩個表Company（幾乎60K記錄）和Position（近60萬條記錄）

Company表：

CompanyID  INT    --PRIMARY KEY 
CompanyName NVARCHAR(100)  
CompanyType INT    --Just can be (1,2,3,4,5,6)  

Position表：

PositionID  INT    --Primary key 
PositionName  NVARCHAR(100) 
CompanyID  INT    --FK point to Company Table 
WorkExperience INT    --Just can be (1,2,3,4,5,6,7,8) 
WorkType   INT    --Just can be (1,2) 
CreateTime  datetime 
UpdateTime  datetime 

我創建了一個NONCLUSTERED INDEX在Company表上：

CREATE NONCLUSTERED INDEX [IX_1] ON [dbo].[Company] 
(
    [CompanyKind] ASC 
) 
INCLUDE ([CompanyName]) ON [PRIMARY] 
GO 

而且我已經創建了兩個NONCLUSTERED INDICES ON的Position表也：

CREATE NONCLUSTERED INDEX [IX_6] ON [dbo].[Position] 
(
    [CompanyID] ASC 
)ON [PRIMARY] 

CREATE NONCLUSTERED INDEX [IX_8] ON [dbo].[Position] 
(
    [UpdateTime] ASC 
) ON [PRIMARY] 

我的分頁存儲過程是這樣的：

ALTER PROC [dbo].[spIndexJobList] 
    @KeyWord NVARCHAR(50) , 
    @WorkExperience INT , 
    @WorkType INT , 
    @CompanyType INT , 
    @PageSize INT , 
    @PageNumber INT 
    --@RowCount INT OUTPUT 
AS 
    DECLARE @RowStart INT 
    DECLARE @RowEnd INT 
    DECLARE @SQL NVARCHAR(4000) 
    DECLARE @ParamDefinition NVARCHAR(2000) 

    SET @SQL = N'SELECT C.CompanyID,C.CompanyName,P.PositionName,P.PositionID,P.UpdateTime, Row_number() OVER (ORDER BY P.UpdateTime DESC) AS RowNumber FROM Company C INNER JOIN Position P ON C.CompanyID=P.CompanyID WHERE 1=1 ' 
    IF @KeyWord!='' 
     SET @SQL = @SQL + ' AND PositionName LIKE @KeyWord' 
    IF @WorkExperience !=0 
     SET @SQL = @SQL + ' AND P.WorkExperience=@WorkExperience' 
    IF @CompanyType != 0 
     SET @SQL = @SQL + ' AND C.CompanyType=@CompanyType' 
    IF @WorkType !=0 
     SET @SQL = @SQL + ' AND P.WorkType=@WorkType' 
    SET @ParamDefinition = ' @KeyWord NVarchar(50), 
          @WorkExperience INT, 
          @WorkType  INT, 
          @CompanyType  INT, 
          @PageSize INT, 
          @PageNumber INT' 
    IF @PageNumber > 0 
     BEGIN 
      SET @PageNumber = @PageNumber - 1 
      SET @RowStart = @PageSize * @PageNumber + 1 ; 
      SET @RowEnd = @RowStart + @PageSize - 1 ; 
      SET @SQL = ' 
     WITH AllJobs 
      AS (' + @SQL 
       + ') 

    SELECT *,(SELECT Count(RowNumber) FROM AllJobs) AS TotalRows FROM AllJobs WHERE RowNumber >=' 
       + STR(@RowStart) + ' AND RowNumber <= ' + STR(@RowEnd) + '' 

      EXECUTE sp_Executesql @SQL, @ParamDefinition, 
       @KeyWord, @WorkExperience,@WorkType, 
       @CompanyType, @PageSize, @PageNumber 

     END 

我的調用語句是這樣的：

SET STATISTICS IO ON 
DECLARE @return_value int 
EXEC @return_value = [dbo].[spIndexJobList] 
     @KeyWord='', 
     @WorkExperience = 3, 
     @CompanyType = 2, 
     @WorkType =1, 
     @PageSize = 30, 
     @PageNumber =2000 

SELECT 'Return Value' = @return_value 
GO 
SET STATISTICS IO OFF 

// ----------------------------------------------- ------------------------

(30 row(s) affected) 
Table 'Company'. Scan count 3, logical reads 632, physical reads 0 
Table 'Position'. Scan count 3, logical reads 4865, physical reads 0 
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0 
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0 

// ----------------------------------------- ------------------------------

的執行計劃提示上（WorkExperience，WorkType缺失索引）。 但創建索引後（WorkExperience，WorkType）查詢速度較慢。

任何人給我的一些建議將非常感激。對不起，我的英語不好！

Answer 1

DDL：

公司表：

CompanyID  INT NOT NULL PK 
CompanyName NVARCHAR(100) NOT NULL  
CompanyType TINYINT NOT NULL  

職位表：

PositionID  INT NOT NULL PK 
PositionName  NVARCHAR(100) NOT NULL 
CompanyID  INT NOT NULL 
WorkExperience TINYINT NOT NULL 
WorkType   TINYINT NOT NULL 
CreateTime  SMALLDATETIME 
UpdateTime  SMALLDATETIME 

指數：

CREATE NONCLUSTERED INDEX IX_Position 
    ON Position (WorkExperience, WorkType, PositionName) 
    INCLUDE (UpdateTime) 

SP：

ALTER PROC [dbo].[spIndexJobList] 

     @KeyWord NVARCHAR(50) 
    , @WorkExperience TINYINT 
    , @WorkType TINYINT 
    , @CompanyType INT 
    , @PageSize INT 
    , @PageNumber INT 

AS BEGIN 

    SET NOCOUNT ON; 

    IF @PageNumber > 0 BEGIN 

      DECLARE 
       @RowStart INT 
       , @RowEnd INT 
       , @SQL NVARCHAR(4000) 
       , @ParamDefinition NVARCHAR(500) 

      SELECT @SQL = N' 
       SELECT 
         c.CompanyID 
        , c.CompanyName 
        , p.PositionName 
        , p.PositionID 
        , p.UpdateTime 
        , RowNumber = ROW_NUMBER() OVER (ORDER BY p.UpdateTime DESC) 
       FROM dbo.Company c 
       JOIN dbo.Position p ON c.CompanyID = p.CompanyID 
       WHERE 1=1 ' 
       + CASE WHEN @KeyWord != '' THEN ' AND PositionName LIKE @KeyWord' ELSE '' END 
       + CASE WHEN @WorkExperience != 0 THEN ' AND p.WorkExperience = @WorkExperience' ELSE '' END 
       + CASE WHEN @CompanyType != 0 THEN ' AND c.CompanyType = @CompanyType' ELSE '' END 
       + CASE WHEN @WorkType != 0 THEN ' AND p.WorkType = @WorkType' ELSE '' END 

      SET @ParamDefinition = '@KeyWord NVARCHAR(50), 
            @WorkExperience INT, 
            @WorkType INT, 
            @CompanyType INT, 
            @PageSize INT, 
            @PageNumber INT' 

      SELECT 
       @PageNumber = @PageNumber - 1 
       , @RowStart = @PageSize * @PageNumber + 1 
       , @RowEnd = @RowStart + @PageSize - 1 
       , @SQL = ' 
      WITH AllJobs AS (' + @SQL + ') 
      SELECT * 
      FROM AllJobs a 
      CROSS JOIN (
       SELECT TotalRows = Count(RowNumber) 
       FROM AllJobs 
     ) t 
      WHERE a.RowNumber BETWEEN ' + STR(@RowStart) + ' AND ' + STR(@RowEnd) 

      EXEC sys.sp_executesql 
       @SQL, 
       @ParamDefinition, 
       @KeyWord, 
       @WorkExperience, 
       @WorkType, 
       @CompanyType, 
       @PageSize, 
       @PageNumber 

    END 

END 

手冊：

http://sqlblog.com/blogs/aaron_bertrand/archive/2009/10/12/bad-habits-to-kick-using-the-wrong-data-type.aspx

Answer 2

我將在當前位置創建一個非聚集索引，像這樣：

CREATE NONCLUSTERED INDEX IX_Position_WorkExperienceWorkTypePositionName 
ON Position (WorkExperience, WorkType, PositionName) 
INCLUDE (PositionID, UpdateTime) 

Answer 3

另外我想在公司創建另一個非聚集索引象下面這樣：

CREATE NONCLUSTERED INDEX IX_Company_CompanyId_Type 
ON Company(CompanyId,CompanyType) 

因爲在where子句中包括「C.CompanyType=@CompanyType」，如果沒有這個指標，這種情況引起了表掃描公司。 有了這個索引，它就是索引查找。

Answer 4

Company.CompanyID和Position.CompanyID應該被編入索引，並且您還可以利用CLUSTER對這兩列進行索引，以便使這些行在物理上與其索引同步排序。這應該可以顯着提高性能。