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FIX: An AWE system uses more memory for sorting or for hashing than a non-AWE system in SQL Server 2000

Article ID: 831999 - View products that this article applies to.

Bug #: 469995 (Shiloh_bugs)

SYMPTOMS

The memory that SQL Server uses during sorting and hashing operations is allocated from the buffer pool as a stolen buffer. Stolen buffers must always remain in the virtual address space. They cannot be unmapped to a Microsoft Windows 2000 Address Windowing Extensions (AWE) location. SQL Server uses a throttle to limit how much memory can be used for sorting and for hashing. SQL Server limits the memory for these reasons:

So that the whole buffer pool will not be consumed by stolen buffers.
So that the buffer pool can continue to serve as a data cache.

On systems with AWE enabled, the computation of how much memory can be used as workspace memory for sorting and for hashing is sometimes higher than it is on a non-AWE system. Because stolen buffers must always remain in the address space, the additional AWE memory should be irrelevant to this computation. The fix that is discussed in this article corrects the problem so that the computation of the workspace available for sorting and for hashing is consistent across both configurations.

Because of the miscalculation, sort and hash operations may try to use more memory from the buffer pool than can remain mapped. As a result, a BPool::Map error that is similar to the following is written to the SQL Server error log followed by the output of the DBCC MEMORYSTATUS command:

2003-06-23 04:17:14.86 spid153 BPool::Map: no remappable address found.
2003-06-23 04:17:15.04 spid92 Buffer Distribution: Stolen=133972 Free=10785 Procedures=17346 Inram=0 Dirty=155429 Kept=0 I/O=2, Latched=988, Other=513478
2003-06-23 04:17:15.06 spid92 Buffer Counts: Commited=832000 Target=832000 Hashed=669897 InternalReservation=1514 ExternalReservation=4255 Min Free=1024
2003-06-23 04:17:15.06 spid92 Procedure Cache: TotalProcs=8505 TotalPages=17346 InUsePages=6439
2003-06-23 04:17:15.06 spid92 Dynamic Memory Manager: Stolen=25253 OS Reserved=1776 OS Committed=1735 OS In Use=1644 Query Plan=17383 Optimizer=0 General=7999 Utilities=243 Connection=907
2003-06-23 04:17:15.06 spid92 Global Memory Objects: Resource=3259 Locks=102 SQLCache=773 Replication=2 LockBytes=2 ServerGlobal=3528 Xact=110
2003-06-23 04:17:15.06 spid92 Query Memory Manager: Grants=6 Waiting=0 Maximum=140712 Available=10409

In the output that is shown earlier, you can see that SQL Server will allow multiple queries that are requesting a total of 140712 buffers to run concurrently. In the earlier example, there are six queries that are executing with sorts or with hashes. These six queries have been granted the use of 130303 buffers (140712 - 10409 = 130303).

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RESOLUTION

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

(http://support.microsoft.com/kb/290211/ )

How to obtain the latest SQL Server 2000 service pack

Hotfix information

The English version of this fix 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     
   02-Oct-2003  20:59  2000.80.867.0      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
   08-Feb-2003  06:40  2000.80.765.0      90,692  Msgprox.dll      
   01-Apr-2003  02:07                      1,873  Odsole.sql
   05-Apr-2003  01:46  2000.80.800.0      62,024  Odsole70.dll     
   07-May-2003  20:41  2000.80.819.0      25,144  Opends60.dll     
   02-Apr-2003  21:48  2000.80.796.0      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
   06-Sep-2003  01:36                  1,090,932  Replmerg.sql
   06-Sep-2003  07:18  2000.80.858.0     221,768  Replprov.dll     
   06-Sep-2003  07:18  2000.80.858.0     307,784  Replrec.dll      
   06-Sep-2003  00:00                  1,087,150  Replsys.sql
   13-Aug-2003  16:28                    986,603  Repltran.sql
   22-Oct-2003  00:08  2000.80.871.0      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
   05-Aug-2003  21:06                    127,884  Sp3_serv_uni.sql
   01-Jun-2003  01:01  2000.80.818.0   4,215,360  Sqldmo.dll       
   07-Apr-2003  17:44                     25,172  Sqldumper.exe    
   19-Mar-2003  18:20  2000.80.789.0      28,672  Sqlevn70.rll
   27-Sep-2003  04:42  2000.80.865.0     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       
   08-Feb-2003  06:40  2000.80.765.0      57,920  Sqlrepss.dll     
   05-Nov-2003  20:52  2000.80.876.0   7,606,353  Sqlservr.exe     
   25-Jul-2003  21:44  2000.80.845.0     590,396  Sqlsort.dll      
   08-Feb-2003  06:40  2000.80.765.0      45,644  Sqlvdi.dll       
   02-Oct-2003  20:59  2000.80.867.0      33,340  Ssmslpcn.dll     
   01-Jun-2003  01:01  2000.80.818.0      82,492  Ssnetlib.dll     
   01-Jun-2003  01:01  2000.80.818.0      25,148  Ssnmpn70.dll     
   28-Oct-2003  04:21  2000.80.873.0     123,456  Stardds.dll      
   01-Jun-2003  01:01  2000.80.818.0     158,240  Svrnetcn.dll     
   31-May-2003  18:59  2000.80.818.0      76,416  Svrnetcn.exe     
   30-Apr-2003  23:52  2000.80.816.0      45,132  Ums.dll          
   02-Jul-2003  00:19  2000.80.834.0      98,816  Xpweb70.dll

Note Because of file dependencies, the most recent hotfix or feature that contains these files may also contain additional files.

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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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

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MORE INFORMATION

If the BPool::Map error occurs while a DBCC DBREINDEX statement or a CREATE INDEX statement is running, see the following article in the Microsoft Knowledge Base:

838459

(http://support.microsoft.com/kb/838459/ )

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

Microsoft Knowledge Base article 838459 discusses a fix that may be more likely to explain the true cause of the error.

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