How Can I Efficiently Implement Paging in SQL Server 2008 for Large Datasets?

Paging Methods in SQL Server 2008

With large datasets, it's crucial to implement efficient paging mechanisms to avoid overwhelming users and system resources. This article explores alternatives for paging large result sets in SQL Server 2008, discussing their merits and offering a highly performant stored procedure solution.

Approaching Paging

One common approach is to add a row number column to the table and query based on it. However, this adds overhead to the table and can impact performance.

An Efficient Stored Procedure Solution

A more efficient method is to use a stored procedure that utilizes a sequential identity column or a suitable sorting column. The stored procedure:

• Calculates the first row number based on the page number and page size.
• Selects the first row ID using an efficient ORDER BY clause.
• Limits the result set to the page size using ROWCOUNT.
• Queries the table using the first row ID as a starting point, maintaining the sort order.

The following T-SQL stored procedure demonstrates this approach:

CREATE PROCEDURE dbo.PagingTest
(
    @PageNumber int,
    @PageSize int
)
AS
BEGIN
    DECLARE @FirstId int, @FirstRow int;

    SET @FirstRow = ( (@PageNumber - 1) * @PageSize ) + 1;
    SET ROWCOUNT @FirstRow;

    SELECT @FirstId = [Id]
    FROM dbo.TestTable
    ORDER BY [Id];

    SET ROWCOUNT @PageSize;

    SELECT *
    FROM dbo.TestTable
    WHERE [Id] >= @FirstId
    ORDER BY [Id];

    SET ROWCOUNT 0;
END;

This stored procedure is CPU- and read-efficient, even for tables with a large number of rows. It also handles non-unique sorting columns effectively by incorporating a second column in the ORDER BY clause.

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