Microsoft KB Archive/838459

= FIX: You may receive a BPool::Map warning when you create or rebuild indexes by using the awe enabled configuration option =

Article ID: 838459

Article Last Modified on 11/2/2007

-

APPLIES TO


 * Microsoft SQL Server 2000 Developer Edition
 * Microsoft SQL Server 2000 Standard Edition
 * Microsoft SQL Server 2000 Enterprise Edition
 * Microsoft SQL Server 2000 Personal Edition
 * Microsoft SQL Server 2000 Enterprise Edition
 * Microsoft SQL Server 2000 Workgroup Edition
 * Microsoft SQL Server 2000 Developer Edition
 * Microsoft SQL Server 2000 Enterprise Edition 64-bit

-



Bug #: 471227 (SHILOH_BUGS)



Microsoft SQL Server 2000 fixes are distributed as one downloadable file. Because the fixes are cumulative, each new release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2000 fix release.



SYMPTOMS
When you run a CREATE INDEX statement or a DBCC DBREINDEX statement on a computer that is running SQL Server, and the awe enabled configuration option is set to 1, the following BPool::Map warning and the DBCC MEMORYSTATUS statement may be written to the SQL Server error log:

2004-02-26 07:36:21.10 spid52 BPool::Map: no remappable address found.

2004-02-26 07:36:21.24 spid52 Buffer Distribution: Stolen=149242 Free=389930 Procedures=2 Inram=0 Dirty=92791 Kept=0 I/O=0, Latched=10, Other=264025

2004-02-26 07:36:21.24 spid52 Buffer Counts: Commited=896000 Target=896000 Hashed=356826 InternalReservation=104 ExternalReservation=280 Min Free=224

2004-02-26 07:36:21.24 spid52 Procedure Cache: TotalProcs=1 TotalPages=2 InUsePages=2

2004-02-26 07:36:21.24 spid52 Dynamic Memory Manager: Stolen=921 OS Reserved=1600 OS Committed=1559 OS In Use=1557 Query Plan=13 Optimizer=0 General=1712 Utilities=23 Connection=58

2004-02-26 07:36:21.24 spid52 Global Memory Objects: Resource=1495 Locks=671 SQLCache=69 Replication=2 LockBytes=2 ServerGlobal=43 Xact=21

2004-02-26 07:36:21.24 spid52 Query Memory Manager: Grants=1 Waiting=0 Maximum=150588 Available=1992

Note The index that is being created must reside in a database that is either set to the simple recovery model or to the bulk logged recovery model.



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

290211 How to obtain the latest SQL Server 2000 service pack

Hotfix information
The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.   Date         Time   Version            Size    File name 31-May-2003 18:45  2000.80.818.0      78,400  Console.exe 28-Oct-2003 04:21  2000.80.873.0     315,968  Custtask.dll 30-Jan-2004 16:29  2000.80.911.0      33,340  Dbmslpcn.dll 25-Apr-2003 02:12                    786,432  Distmdl.ldf 25-Apr-2003 02:12                  2,359,296  Distmdl.mdf 30-Jan-2003 01:55                        180  Drop_repl_hotfix.sql 12-Sep-2003 03:26  2000.80.859.0   1,905,216  Dtspkg.dll 26-Aug-2003 20:16  2000.80.854.0     528,960  Dtspump.dll 23-Jun-2003 22:40  2000.80.837.0   1,557,052  Dtsui.dll 23-Jun-2003 22:40  2000.80.837.0     639,552  Dtswiz.dll 24-Apr-2003 02:51                    747,927  Instdist.sql 03-May-2003 01:56                      1,581  Inst_repl_hotfix.sql 30-Jan-2004 16:29  2000.80.911.0      90,692  Msgprox.dll 01-Apr-2003 02:07                      1,873  Odsole.sql 30-Jan-2004 16:29  2000.80.911.0      62,024  Odsole70.dll 30-Jan-2004 16:29  2000.80.911.0      25,144  Opends60.dll 30-Jan-2004 16:28  2000.80.911.0      57,904  Osql.exe 02-Apr-2003 23:15  2000.80.797.0     279,104  Pfutil80.dll 04-Aug-2003 18:17                    550,780  Procsyst.sql 12-Sep-2003 00:37                     12,305  Qfe469315.sql 22-May-2003 22:57                     19,195  Qfe469571.sql 30-Jan-2004 01:16                  1,090,380  Replmerg.sql 30-Jan-2004 16:29  2000.80.911.0     221,768  Replprov.dll 30-Jan-2004 16:29  2000.80.911.0     307,784  Replrec.dll 29-Jan-2004 23:24  2000.80.911.0     159,813  Replres.rll 06-Sep-2003 00:00                  1,087,150  Replsys.sql 13-Aug-2003 16:28                    986,603  Repltran.sql 30-Jan-2004 16:29  2000.80.911.0     287,304  Rinitcom.dll 30-Jan-2004 16:29  2000.80.911.0      57,916  Semnt.dll 29-Jul-2003 20:13  2000.80.819.0     492,096  Semobj.dll 31-May-2003 18:27  2000.80.818.0     172,032  Semobj.rll 02-Jan-2004 19:42  2000.80.904.0      53,832  Snapshot.exe 09-Dec-2003 20:07                    117,834  Sp3_serv_uni.sql 05-Feb-2004 00:46  2000.80.913.0      28,672  Sqlagent.dll 05-Feb-2004 00:47  2000.80.913.0     311,872  Sqlagent.exe 19-Feb-2004 18:02  2000.80.916.0     168,001  Sqlakw32.dll 30-Jan-2004 16:29  2000.80.911.0   4,215,360  Sqldmo.dll 07-Apr-2003 17:44                     25,172  Sqldumper.exe 29-Jan-2004 23:17  2000.80.911.0      28,672  Sqlevn70.rll 05-Mar-2004 17:13  2000.80.922.0     180,792  Sqlmap70.dll 03-Sep-2003 02:56  2000.80.857.0     188,992  Sqlmmc.dll 02-Sep-2003 23:03  2000.80.857.0     479,232  Sqlmmc.rll 22-Oct-2003 00:08  2000.80.871.0     401,984  Sqlqry.dll 30-Jan-2004 16:29  2000.80.911.0      57,920  Sqlrepss.dll 09-Mar-2004 19:54  2000.80.922.0   7,614,545  Sqlservr.exe 30-Jan-2004 16:29  2000.80.911.0     590,396  Sqlsort.dll 30-Jan-2004 16:29  2000.80.911.0      45,644  Sqlvdi.dll 30-Jan-2004 16:29  2000.80.911.0     106,588  Sqsrvres.dll 30-Jan-2004 16:29  2000.80.911.0      33,340  Ssmslpcn.dll 30-Jan-2004 16:29  2000.80.911.0      82,492  Ssnetlib.dll 30-Jan-2004 16:29  2000.80.911.0      25,148  Ssnmpn70.dll 28-Oct-2003 04:21  2000.80.873.0     123,456  Stardds.dll 30-Jan-2004 16:29  2000.80.911.0     158,240  Svrnetcn.dll 30-Jan-2004 16:29  2000.80.911.0      76,416  Svrnetcn.exe 30-Apr-2003 23:52  2000.80.816.0      45,132  Ums.dll 30-Jan-2004 16:29  2000.80.911.0      98,872  Xpweb70.dll Note Because of file dependencies, the most recent hotfix or feature that contains these files may also contain additional files.

Note To enable the hotfix, you must enable the trace flag 3940. To enable the trace flag dynamically, run the DBCC TRACEON(-1,3940) command just before you rebuild the index. Then, disable the trace flag by running the DBCC TRACEOFF(-1,3940) command.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.

This problem was first corrected in Microsoft SQL Server 2000 Service Pack 4.



MORE INFORMATION
When a database uses the simple recovery model or the bulk logged recovery model, all dirty pages must be written to disk before the transaction commits. Dirty pages are pages that have been modified but not yet written to disk. SQL Server uses a mechanism that issues asynchronous write requests after a certain number of pages have been modified, even before the transaction commits. In the commit logic, the database engine waits for all asynchronous write requests to complete. However, SQL Server does not use any type of throttling mechanism to limit the number of outstanding asynchronous write requests.

In the circumstances where this problem occurs, the CREATE INDEX operation was building a new nonclustered index immediately after the operation built a clustered index, and the table fit in the cache. Additionally, the table size permitted the CREATE INDEX process to perform an in-memory sort. No intermediate sorted runs must be written to disk. Therefore, the index creation process can read, sort, and dirty pages at a very high rate. The combination of many stolen buffers that were being used for the sort and the lack of throttle in issuing the write operations may cause the whole address space of mappable buffers to be temporarily unavailable.

To resolve this problem, trace flag 3940 was added. Trace flag 3940 throttles the number of concurrent asynchronous write requests to 1,024. When this trace flag is enabled, the code that is flushing dirty pages for that transaction waits for every 1,024th write operation to complete before the code issues additional write requests. This throttling might theoretically cause a very small performance degradation. Because the problem occurs in very few cases, Microsoft decided to fix this problem by using a trace flag so that any customer who does not receive the BPool::Map warning is not affected by the possible performance difference.

This problem may theoretically occur because of an operation other than a CREATE INDEX operation, but other causes have not been discovered. To confirm that this bug was the likely cause of the BPool::Map warning, look for the following additional symptoms from the DBCC MEMORYSTATUS output in the SQL Server error log:
 * Buffer Distribution: Stolen is a large value and typically accounts for at least one third of the mappable buffers. The exact mappable count depends on many factors, including whether Microsoft Windows is running with the /3GB switch and the physical memory in the computer. Generally, the mappable count is around 200 thousand for a 2 GB address space and around 320 thousand for a 3 GB address space.
 * The difference between the Query Memory Manager: Maximum value and the Query Memory Manager: Available value is typically within several thousand of the stolen value.
 * Buffer Distribution: Dirty is large, typically more than 80 thousand buffers.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbbug kbfix kbqfe kbsqlserv2000presp4fix kbhotfixserver KB838459

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.