Microsoft KB Archive/156430

= PRB: Slow SQL Server Connections Using Named Pipes with Win 95 =

Article ID: 156430

Article Last Modified on 12/3/2003

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APPLIES TO


 * Microsoft SQL Server 4.21a Standard Edition
 * Microsoft SQL Server 6.0 Standard Edition
 * Microsoft SQL Server 6.5 Standard Edition
 * Microsoft Windows 95

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This article was previously published under Q156430



SYMPTOMS
When you run SQL Server applications on a computer running Windows 95, you may experience slow connections to Microsoft SQL Server using named pipes. This applies to both ODBC and DB-Library applications. The same applications will run normally on a computer running Windows NT, or using other interprocess communication (IPC) connections, such as TCP/IP sockets or SPX.

Also when reading data from a named pipe when the client is on Windows 95, calls to blocking ReadFile will not return immediately when there is no data present. When there is data present, a blocking read may take up to 1 second per message.



CAUSE
This problem is caused by Windows 95 NWLink Direct-Hosting, which was implemented to enhance the general network performance of Windows 95. A client using Direct-Hosting may experience a delay in reading from named pipes.



MORE INFORMATION
Direct-Hosting is enabled by default, so you may run into this problem if you have NWLink installed and configured as the default transport protocol. However, if you have other transport protocols loaded at the same time, you may not encounter this problem, because Windows 95 may use named pipes over other protocols, rather than NWLink IPX/SPX.

This problem does not occur with 16-bit Windows applications, because the 16-bit named pipes Net-Library for Windows peeks the named pipes first until data is available, and then begins to read. This method avoids the delay with Direct-Hosting in its own Peeknamedpipe messages.

Additional query words: DirectHosting netlib net-lib performance

Keywords: kbfix kbinterop kbpipes kbnetwork kbdocfix kbipc kbprb KB156430

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