Microsoft KB Archive/257765

= SNA DDM Service Fails with an Access Violation When Too Many Tables Open =

Article ID: 257765

Article Last Modified on 11/26/2003

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APPLIES TO


 * Microsoft SNA Server 4.0
 * Microsoft SNA Server 4.0 Service Pack 1
 * Microsoft SNA Server 4.0 Service Pack 2
 * Microsoft SNA Server 4.0 Service Pack 3

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This article was previously published under Q257765



SYMPTOMS
The SNA DDM Service (Ddmserv.exe) may fail with an Access Violation error message, causing the following events to be logged:

Event ID: 3

Source: SNA DDM Service

Description: DDM Requestor has encountered exception 6be at location IOpenRowset::OpenRowset

If the VSAM Provider is invoked from within an Active Server Page, the following event may also be logged:

Event ID: 5

Source: Active Server Pages

Description: Error: File (file.asp) Unexpected error

A Drwtsn.log file is also created, indicating an Access Violation failure in Ddmserv.exe in one of the following routines:

- ddmserv!mwOpen

- ddmserv!InitializeFileInfo

- ddmserv!IsKeyInRange

- ddmserv!mwConnect

For example:

Application exception occurred:

App: exe\ddmserv.dbg (pid)

When: date @ time

Exception number: c0000005 (access violation)

[...]

State Dump for Thread Id 0xa8

eax=00000001 ebx=015c7690 ecx=00000000 edx=00017fff esi=041919e0 edi=00000000

eip=01008a83 esp=05fef8e0 ebp=032b7250 iopl=0 nv up ei pl nz ac pe nc

cs=001b ss=0023 ds=0023 es=0023 fs=0038 gs=0000 efl=00000212

function: mwOpen

01008a68 5f pop edi

01008a69 5e pop esi

01008a6a 5d pop ebp

01008a6b 5b pop ebx

01008a6c 81c450020000 add esp,0x250

01008a72 c3 ret

01008a73 8b83e4000000 mov eax,[ebx+0xe4] ds:015c7774=00000001

01008a79 85c0 test eax,eax

01008a7b 7e21 jle mwOpen+0x4ee (01008a9e)

01008a7d 8b8bec0c0000 mov ecx,[ebx+0xcec] ds:015c837c=00000000

FAULT ->01008a83 8929 mov [ecx],ebp ds:00000000=????????


 * Stack Back Trace *

FramePtr ReturnAd Param#1 Param#2 Param#3 Param#4 Function Name

05fefb3c 0100323f 0000000f 00076fbc 00076fcc 036e6a08 ddmserv!mwOpen

05feff28 00000010 00076fb8 0000004c 00000004 00078ad0 ddmserv!DDMAgent_mwOpen



CAUSE
The DDMSERV process is not properly handling new open requests when the maximum number of concurrent tables are open (157). Also, internal fileinfo structures are not being properly protected across different threads of the process.



RESOLUTION
To resolve this problem, obtain the latest service pack for SNA Server 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack



STATUS
Microsoft has confirmed that this is a problem in Microsoft SNA Server version 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3.

This problem was first corrected in SNA Server 4.0 Service Pack 4.



MORE INFORMATION
This update also increases the maximum number of concurrently open tables (files) to 1024 (from 157), and increases the maximum connections to 1024 (from 128).

Keywords: kbbug kbfix kbsna400presp4fix kbqfe kbsna400sp4fix KB257765

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