Sql-server – Does “use AWE to allocate memory” do anything on a SQL Server 2008 R2 64bit Windows 2003 system

You say you enabled AWE on SQL Server but did you activate /PAE in the boot.ini file?

PAE enables Large Memory support.

Activate PAE in Windows 32Bit Enterprise

c:\boot.ini

[boot loader]
timeout=30
default=multi(0)disk(2)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Windows Server 2003, Enterprise" /fastdetect /PAE

http://support.microsoft.com/kb/283037

Lock Pages in Memory

As part of enabling AWE, you would also need to give the SQL Server Service user the right to Lock Pages in Memory. Enabling this option in the Group Policy dialog (gpedit.msc), prevents Windows from paging memory out of the SQL Server working set for its own needs, especially if memory starts to run low on Windows.

http://msdn.microsoft.com/en-us/library/ms190730.aspx

Monitoring AWE Memory Usage

To test AWE usage, I setup a Windows 2003 Enterprise SP2 with PAE enabled in boot.ini. I used SQL Server 2005 32bit Standard SP4.

The total physical memory is 8192Mb. The max memory setting for SQL Server is configured at 8192 and the minimum is at 2048.

Does SQL Server see AWE on startup.

2012-02-09 07:27:51.35 Server Address Windowing Extensions is enabled. This is an informational message only; no user action is required.

Is SQL Server using Locked Pages for the Buffer Pool

According to some blogs, I should be seeing this message, but I'm not.

Using locked pages for buffer pool. This is an informational message only; no user action is required.

Memory being allocated through AWE

SELECT  SUM(awe_allocated_kb) / 1024 AS awe_allocated_mb
FROM    sys.dm_os_memory_clerks ;

[3648]

Memory allocated to Multi-Page memory.

select sum(multi_pages_kb)/1024 as [MultiPage Memory, MB] from sys.dm_os_memory_clerks

[14]

Multi-page memory can not use AWE allocated memory

Memory being used outside the buffer pool

SELECT sum(multi_pages_kb 
 + virtual_memory_committed_kb + shared_memory_committed_kb) AS
 [Memory used outside BPool, mb]
FROM sys.dm_os_memory_clerks 
WHERE type <> 'MEMORYCLERK_SQLBUFFERPOOL'

[24]

Overall memory allocation by component

SELECT type, (single_pages_kb)/1024 as Single_Pages_MB, (multi_pages_kb)/1024 
AS Multi_Pages_MB, (awe_allocated_kb)/1024 as AWE_allocated_MB
FROM sys.dm_os_memory_clerks
GROUP BY type
ORDER BY 2 DESC

This will show you how single-page and multi-page memory is being used by each component. It will also tell you which one is able to benefit from AWE.

Mutli-page : when request exceeds 8Kb

Single-page : when request is less than or equal to 8Kb

As a side note, I have found sp_whoisactive very helpful in finding slow queries, memory hogs and just about everything that's going on in SQL Server. Here is a link that Brent Ozar provides on how to set it up and use it.

http://www.brentozar.com/archive/tag/sp_whoisactive/

A couple of things to check into. These two you could capture with a server-side trace or extended events (though I haven't used the latter for this specific task):

• explicit calls to DBCC FREEPROCCACHE or DBCC FREESYSTEMCACHE
• certain explicit calls to RECONFIGURE (or RECONFIGURE WITH OVERRIDE)

If you see these calls happening often, you'll want to figure out where they're coming from and why, because they absolutely flush the procedure cache.

Also check the error log for events containing the text "cachestore flush":

EXEC xp_readerrorlog 0, 1, N'cachestore flush';

If you see these events make sure the database in question does not have the option AUTO_CLOSE on. You may want to make sure this isn't the case anyway, and it is often turned on with Web Edition since this edition is typically used to hold a lot of infrequently-used databases at a web host.