How to change the table for better performance

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Hi All

I have the following table without any primary key and Index. This table contains more than 20 Million records. Hence the Select statement is very slow (more than 20 sec for a date range 2012-12-01 to 2012-12-31).

SQL

CREATE TABLE tblDataLog(
    [DATE_TIME] [datetime] NOT NULL,
    [5] [float] NULL,
    [6] [float] NULL,
    [7] [float] NULL,
    [8] [float] NULL,
    [9] [float] NULL,
    [10] [float] NULL,
    [11] [float] NULL,
    [12] [float] NULL,
    [13] [float] NULL,
    [14] [float] NULL,
    [15] [float] NULL,
    [16] [float] NULL,
    [17] [float] NULL,
    [18] [float] NULL,
    [19] [float] NULL,
    [20] [float] NULL,
    [21] [float] NULL,
    [22] [float] NULL,
    [23] [float] NULL,
    [24] [float] NULL,
    [25] [float] NULL,
    [26] [float] NULL,
    [27] [float] NULL,
    [28] [float] NULL,
    [29] [float] NULL,
    [30] [float] NULL,
    [31] [float] NULL,
    [32] [float] NULL,
    [33] [float] NULL,
    [34] [float] NULL,
    [35] [float] NULL,
    [36] [float] NULL,
    [37] [float] NULL,
    [38] [float] NULL,
    [39] [float] NULL,
    [40] [float] NULL,
    [41] [float] NULL
) ON [PRIMARY]

Please suggest me how to optimize this table.

Thanks.
Willington

Posted 3-Jan-13 20:45pm

willington.d

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3 solutions

Solution 2

you should add auto-incr primary key
and then apply indexing

refer this link having same problem you are facing

http://stackoverflow.com/questions/1716798/sql-server-2008-ordering-by-datetime-is-too-slow[^]

Happy Coding!
:)

Posted 3-Jan-13 21:47pm

Aarti Meswania

Solution 1

Hi,

Keep an ID column as primary key and use indexing on any two columns for retrieving the records.
See the following link for indexing.

CREATE INDEX (Transact-SQL)
Overview of SQL Server 2005/2008 Table Indexing
SQL Server Journey with SQL Authority

Thanks

Posted 3-Jan-13 20:57pm

sisir patro

Comments

willington.d 4-Jan-13 3:43am

Hi, I have added ID as primarykey column and Created NonClustered(Date_Time) Index on the table. Now the issue is, it is very slow to execute the following Query

SELECT DATE_TIME, [794] AS CT, [91] AS BID,
ROW_NUMBER() OVER (PARTITION BY [91] ORDER BY [794] DESC) AS Row_No
FROM tblDataLog (NOLOCK)
WHERE DATE_TIME >= '2012-12-01 12:00:00' and DATE_TIME <= '2012-12-31 11:59:59'

it is taking more than 30sec.

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willington.d · Accepted Answer · 2013-02-21T19:48:00

Solution 3

Hi All,

Thanks for reply. I have solved the issue by creating NonClustered index on Date_Time Column and included the columns which are frequently used in the select clause.

SQL

CREATE INDEX NDX_tblTestData
     ON tblTestData
        (DATE_TIME) INCLUDE (Col1, Col2, Col7);

Posted 21-Feb-13 19:48pm

willington.d