DOCUMENT:Q182375  02-APR-2000  [sna]
TITLE   :API or Message Tracing May Cause SNA Server Process to Hang
PRODUCT :Microsoft SNA Server
PROD/VER:WINDOWS:3.0,3.0 SP1,3.0 SP2,4.0
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft SNA Server, versions 3.0, 3.0 SP1, 3.0 SP2, 4.0 
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SYMPTOMS
========

When you do API or Message tracing on an SNA Server process (such as the Shared
Folders Gateway Service), the process may hang in certain conditions, causing
other problems such as a loss of network connectivity to the SNA Server
computer.

The SNA Server service or Win32 SNA application may hang unexpectedly if Message
tracing or API tracing is enabled. This problem does not affect internal
tracing. When the process hangs, the SNA session status may continue to indicate
an active status and the SNA data flow on the session will be suspended.

This problem can cause the SNA Server service to hang while message tracing is
enabled. The types of message tracing that can cause this problem to occur are
Server Data Link Control (DLC), LU 6.2, and 3270. An SNA Server link service may
also hang when enabling DLC message traces. If this occurs, the SNA Server
service or SNA link service will become unresponsive (for example, existing
clients will lose their sessions), and any attempt to stop the SNA Server
service will show a perpetual "Stopping" status.

This problem can also cause a Win32 SNA application to hang while API or message
tracing is enabled. If this occurs, the SNA Application traces will not have
been flushed to disk; therefore, the API or message traces will not indicate the
last API call issued by the application. The trace file size may have reached
its maximum configured size when this problem occurs. SNA Application full
internal traces will indicate that it is still responding to SNA Server
"keepalive" messages.

This problem may occur more frequently when a small trace file size is
configured, or if there is a large amount of message activity that causes the
trace files to fill quickly.

CAUSE
=====

The tracing mechanism within SNA Server is not properly flushing the trace
statements to the file.


STATUS
======

Microsoft has confirmed this to be a problem in SNA Server 3.0 and 4.0. This
problem was corrected in the latest SNA Server versions 3.0 and 4.0 U.S. Service
Packs. For information on obtaining these Service Packs, query on the following
word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION
================

With this update applied, the Trace utility functions correctly.


Additional query words:

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Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ400 kbSNAServ300SP1 kbSNAServ300SP2
Version           : WINDOWS:3.0,3.0 SP1,3.0 SP2,4.0
Issue type        : kbbug
Solution Type     : kbfix

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