BUG: SQLOLEDB Resends Prepared Commands with Client Cursors

ID: Q238355

The information in this article applies to:

Microsoft SQL Server version 7.0
Microsoft Data Access Components version 2.1

BUG #: 55798 (SQLBUG_70)

SYMPTOMS

When using the SQLOLEDB provider with client side cursors and prepared statements, the performance is slower than with SQL Server 6.5 and ODBC. When tracing the SQL statements sent by the client application with SQL Server Profiler, a sequence of statements similar to the following can be observed:

SQL Server 7.0


sp_prepare @P1 output, N'@P1 varchar(40)', N'select au_fname,au_lname from pubs..authors where au_lname like @P1', 1 select @P1
sp_unprepare 1
sp_executesql N'select au_fname,au_lname from pubs..authors where au_lname like @P1', N'@P1 nvarchar(2)', N'M%'

SQL Server 6.5


create proc #oledbsa1(@P1 varchar(40)) as select au_fname,au_lname from pubs..authors where au_lname like @P1
select au_fname,au_lname from pubs..authors where au_lname like 'M%'

CAUSE

As shown in the SQL trace, under these circumstances the SQLOLEDB provider first prepares the statement but sends it again to get the rows for the client side cursor.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next SQL Server service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp

The English version of this fix should have the following file attributes or later:



   Date       Time     Version        Size      File name   Platform
   -----------------------------------------------------------------

   06/25/99   16:04   07.01.0705     540,944   Sqloledb.dll   Intel
   06/25/99   16:04   07.01.0705   1,044,240   Sqloledb.dll   Alpha

NOTE: Due to file dependencies, the most recent hotfix or feature that contains the above files may also contain additional files.

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:

Q154871 Determining If You Are Eligible for No-Charge Technical Support

WORKAROUND

To work around this problem, try either of the following:

Do not use prepared statements.

-or-

Use server based cursors.

STATUS

Microsoft has confirmed this to be a problem in SQL Server version 7.0.

Additional query words: OLE DB


Keywords          : SSrvProg kbbug7.00 kbSQLServ700bug 
Version           : WINDOWS:2.1; winnt:7.0
Platform          : WINDOWS winnt 
Issue type        : kbbug

Last Reviewed: July 30, 1999