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Posted Friday, January 8, 2010 11:14 AM
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I was correct, but did not like this question. None of the options do anything, so they are all equivalent.
Post #844548
Posted Friday, January 8, 2010 11:45 AM


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actually this was a trick for who don't how 64bit env works.

the first 2 options are valid in 32bit env, and I bet that a lot of people will choice AWE settings



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Alex Rosa
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Post #844585
Posted Friday, January 8, 2010 3:27 PM


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Thanks for all of your comments.

Setting Maximum Memory Parameter is also a good option and nothing against this. However, I personally experienced that Maximum Memory Parameter is most useful when lock pages option has been enabled from Windows.

Thanks


Swarndeep

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Post #844723
Posted Monday, January 11, 2010 6:48 AM
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The answer is incorrect. AWE can be used in 64-bit and some people recommend that it should be set because it helps SQL Server manage memory by not allowing the working set to be trimmed. (Note: lock pages in memory must also be set.) This blog entry explains it pretty well.

http://blogs.msdn.com/psssql/archive/2007/10/18/do-i-have-to-assign-the-lock-privilege-for-local-system.aspx


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Post #845340
Posted Monday, January 11, 2010 7:26 AM
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Robert Frasca (1/11/2010)
The answer is incorrect. AWE can be used in 64-bit and some people recommend that it should be set because it helps SQL Server manage memory by not allowing the working set to be trimmed. (Note: lock pages in memory must also be set.) This blog entry explains it pretty well.

http://blogs.msdn.com/psssql/archive/2007/10/18/do-i-have-to-assign-the-lock-privilege-for-local-system.aspx


I agree with the Lock Pages in memory, not what the question asked, but the article clearly suggests that:

This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).
Post #845372
Posted Monday, January 11, 2010 7:46 AM
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Did you read the blog post from the CSS SQL Server group engineers? The AWE switch is NOT ignored and it is recommended as a best practice. Here is a snippet from the blog post:

So, the purpose of AWE for 32bit systems was to access more memory. But for 64bit, AWE APIs are used to avoid a working set trim. So SQL Server will automatically use the AWE APIs provided the 'lock pages in memory' privilege is set (and your are using Enterprise Edition). If you want to read more about the AWE APIs, look here in MSDN: http://msdn2.microsoft.com/en-us/library/aa366527.aspx



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Post #845389
Posted Monday, January 11, 2010 7:54 AM
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Yes I did. Apparently I do not interpret it the same way that you do. I took the following to mean that you did not need to enable AWE to use the AWE API's on 64 Bit. We do not do this with our 64 bit servers. We were able to prevent the working set from being trimmed by merely locking pages in memory (in addition to setting Min/Max Memory properly).


For 64bit systems, the virtual address space limitation is not an issue. However, if an application wants to "lock its memory" or avoid its working set from being trimmed, then it can achieve this by using the AWE APIs. Again, in order to use these APIs, you must have the 'lock pages in memory' privilege set. This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).

Post #845397
Posted Monday, January 11, 2010 8:05 AM


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I never gave a thought to 64 bit Windows/SQL Servers having different built in memory allocation settings than the 32 bit versions.

In fact, I figured that Windows Server 2008 wouldn't need an adjustment in 64 or 32, but I've olny dealt with the 64 bit version so far.

Thanks for the question.


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Post #845409
Posted Monday, January 11, 2010 8:40 AM
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Cliff Jones (1/11/2010)

Again, in order to use these APIs, you must have the 'lock pages in memory' privilege set. This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).



Perhaps we're having a semantic argument. There are a number of articles around that explain how 64-bit memory management works with the AWE Enabled option set. In fact, if you've turned on 'lock pages in memory' I believe you'll find that the AWE Enabled box is checked whether you like it or not; however, if you don't have "lock pages in memory" set then you can't set the AWE enabled switch. The overriding point is that AWE functionality is used on 64-bit machines. It isn't just a 32-bit feature. The difference is that the functionality provides a different set of benefits in a 64-bit environment.


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Post #845458
Posted Monday, January 11, 2010 9:09 AM
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Robert Frasca (1/11/2010)
Cliff Jones (1/11/2010)

Again, in order to use these APIs, you must have the 'lock pages in memory' privilege set. This is why for 64bit systems, you don't need to set the 'awe enabled' option to 1 (it is actually ignored on 64bit systems).



Perhaps we're having a semantic argument. There are a number of articles around that explain how 64-bit memory management works with the AWE Enabled option set. In fact, if you've turned on 'lock pages in memory' I believe you'll find that the AWE Enabled box is checked whether you like it or not; however, if you don't have "lock pages in memory" set then you can't set the AWE enabled switch. The overriding point is that AWE functionality is used on 64-bit machines. It isn't just a 32-bit feature. The difference is that the functionality provides a different set of benefits in a 64-bit environment.


I was not aware of that, point taken. I agree the question was lacking. I think what people should take away from this is that you want to get the memory settings on 64 bit correct; set Min/Max memory, and lock pages in memory. If the working set gets trimmed, performance is in the toilet.

Post #845489
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