Question

Every now and then we get this error from some of our old ASP pages that use a Stored Procedure to return a recordset(usually <2000 rows).

Microsoft OLE DB Provider for ODBC Drivers (0x80040E31)
[Microsoft][ODBC SQL Server Driver]Timeout expired

When I run the SP on the server it runs without an issue but with ASP it just gives a Timeout expired.

When I recompile the SP it fixes the issue and the SP works fine in ASP once more. But then # of days/weeks later I get the same problem either from the same SP/ASP or another. The source tables and ASP are not being changed at all.

It’s got me stumped.

Sample SP:

USE [DB-Name]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER Procedure [dbo].[MY_StoredProcedure]
    @Filter varchar(50) = null,
    @SortOrder bit = 1,
    @SortField varchar(50) = 'MyCol1',
    @Page int = 1,
    @RecordsPerPage int = 20
AS
BEGIN
    SET NOCOUNT ON
    CREATE TABLE #TempTable(RowID int IDENTITY,Col1 int,Col2 varchar(20),Col3 datetime)
    INSERT INTO #TempTable
    SELECT Col1, Col2, Col3 FROM [DB-Table]
    WHERE 
        @Filter is null OR (
            Col1 LIKE '%' + @Filter + '%'
            OR Col2 LIKE '%' + @Filter + '%'
            OR Col3 LIKE '%' + @Filter + '%'
        )       
    ORDER By
        CASE WHEN @SortField = 'MyCol1' AND @SortOrder = 1 THEN Col1 END ASC,
        CASE WHEN @SortField = 'MyCol1' AND @SortOrder = 0 THEN Col1 END DESC,
        CASE WHEN @SortField = 'MyCol2' AND @SortOrder = 0 THEN Col2 END DESC,
        CASE WHEN @SortField = 'MYCol2' AND @SortOrder = 1 THEN Col2 END ASC,
        CASE WHEN @SortField = 'MyCol3' AND @SortOrder = 1 THEN Col3 END ASC,
        CASE WHEN @SortField = 'MyCol4' AND @SortOrder = 0 THEN Col3 END DESC

    -- Find out the first and last record we want
    DECLARE @FirstRec int, @LastRec int
    SELECT @FirstRec = (@Page - 1) * @RecordsPerPage
    SELECT @LastRec = (@Page * @RecordsPerPage + 1)

    -- Now, return the set of paged records, plus, an indiciation of if we have more     records or not!
    SELECT *,TotalRecords=(SELECT COUNT(RowID) FROM #TempTable),MoreRecords=(SELECT     COUNT(RowID) FROM #TempTable TI WHERE TI.RowID >= @LastRec)
    FROM #TempTable
    WHERE 
         RowID > @FirstRec AND RowID < @LastRec

    DROP TABLE #TempTable
    -- Turn NOCOUNT back OFF
    SET NOCOUNT OFF
END
GO

Answer 1

What you have described sounds like an incorrectly cached query plan as a result of parameter sniffing.

It can sometimes be avoided by ensuring your statistics and indexes are up to date.

Suggest you post the stored procedure in question.

The canonical reference is: Slow in the Application, Fast in SSMS?

In SQL Server 2008 onwards you can make use of OPTIMIZE FOR :

SELECT Col1, Col2, Col3 FROM [DB-Table] 
WHERE  
    @Filter is null OR ( 
        Col1 LIKE '%' + @Filter + '%' 
        OR Col2 LIKE '%' + @Filter + '%' 
        OR Col3 LIKE '%' + @Filter + '%' 
    )        
ORDER By 
    CASE WHEN @SortField = 'MyCol1' AND @SortOrder = 1 THEN Col1 END ASC, 
    CASE WHEN @SortField = 'MyCol1' AND @SortOrder = 0 THEN Col1 END DESC, 
    CASE WHEN @SortField = 'MyCol2' AND @SortOrder = 0 THEN Col2 END DESC, 
    CASE WHEN @SortField = 'MYCol2' AND @SortOrder = 1 THEN Col2 END ASC, 
    CASE WHEN @SortField = 'MyCol3' AND @SortOrder = 1 THEN Col3 END ASC, 
    CASE WHEN @SortField = 'MyCol4' AND @SortOrder = 0 THEN Col3 END DESC 
OPTION (OPTIMIZE FOR (@Filter UNKNOWN))

This tells SQL Server to eliminate parameter sniffing for parameter @Filter, and use an average selectivity value (based upon statistics).