FIX: Use of the Jet Provider to Query a Linked Server Text File from SQL Server May Be Very Slow (290415)

The information in this article applies to:

Microsoft SQL Server 2000 (all editions)

This article was previously published under Q290415

BUG #: 236329 (SHILOH_BUGS)
BUG #: 236615 (SHILOH_BUGS)
BUG #: 352865 (SHILOH_BUGS)

SYMPTOMS

When you use the Jet OLEDB Provider (OLE DB Provider for Jet [Text IISAM]) to access a text file from a SQL Server linked server, the query may take a very long time. The slow query performance only occurs when there are a large number of columns in the text file.

CAUSE

The Jet OLEDB Provider is querying the Jet Property Manager on a property-by-property basis for each column. Starting with Jet 4.0 Service Pack 5 (SP5) the query is performed in a bulk mode, which speeds up the query considerably.

RESOLUTION

To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

290211 INF: How to Obtain the Latest SQL Server 2000 Service Pack

This problem has been fixed in the latest edition of the Jet Service Pack. For additional information about how to obtain the latest version of the Jet 4.0 database engine, click the following article number to view the article in the Microsoft Knowledge Base:

239114 How To: Obtain the Latest Service Pack for the Microsoft Jet 4.0 Database Engine

WORKAROUND

To work around the problem, use a different provider to query the text file from SQL Server.

STATUS

Microsoft has confirmed that this is a problem in Microsoft SQL Server 2000. This problem was first corrected in SQL Server 2000 Service Pack 1.

MORE INFORMATION

The computer stops responding (hangs) when SQL Server calls IDBSchemaRowset::GetRowset(DBSCHEMA_COLUMNS).

Steps to Reproduce Behavior

To reproduce the behavior, run the code sample that follows.

NOTE: This sample assumes that the C:\MyDir\TextFile.txt file has 255 columns.

exec sp_addlinkedserver
 @server = 'My Documents',
 @provider = 'Microsoft.Jet.OLEDB.4.0',
 @srvproduct = 'OLE DB Provider for Jet (Text IISAM)',
 @datasrc = 'c:\MyDir\',
 @provstr = 'Text'
go
exec sp_addlinkedsrvlogin 'My Documents', false, NULL, 'admin'
go
SELECT * FROM [My Documents]...[TextFile#txt] 
go
exec sp_droplinkedsrvlogin 'My Documents', null
exec sp_dropserver 'My Documents'
go

Modification Type:	Major	Last Reviewed:	11/13/2003
Keywords:	kbBug kbfix kbSQLServ2000sp1fix KB290415