DOCUMENT:Q163202 08-AUG-2001 [winnt] TITLE :Limit of the Number of Simultaneously Open Root Storage Files PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0 OPER/SYS: KEYWORDS:kbinterop kbnetworkkbbuglist kbfixlist ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== Applications that use StgOpenStorage() or StgCreateDocFile() API calls to open several storage files may fail. This problem does not occur in Windows 95 or Windows NT 3.51. CAUSE ===== Windows NT 4.0 limits the number of simultaneously open root storage files to around 500 PER PROCESS. It should be noted that this is a per process limit (for example, Process 1 can open 498 root storages, at the same time Process 2 can also open 498 root storages, and so on.) Windows 95 and Windows NT 3.51, use a global shared memory heap of 64M; whereas Windows NT 4.0 uses a per-root-open heap of 4MB. Assuming a 2G user address limit for processes, Windows NT 4.0 supports around 500 root opens for a process. RESOLUTION ========== On Windows NT 4.0 per-root-open heap size was further reduced to 2MB allowing around 1000 opens. A reduction in heap size means applications will not be able to open as many sub-storages or keep as many transacted changes uncommitted. STATUS ====== Microsoft has confirmed this to be a problem in Microsoft Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces): S E R V P A C K Additional query words: 4.00 prodnt ====================================================================== Keywords : kbinterop kbnetwork kbbuglist kbfixlist Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : winnt:4.0 Issue type : kbbug ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.