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Secrets of Advanced Windowing Extensions: Making Sure Your SQL Server Has "Air to Breathe"

by Jörg A.
Consultant,

I'd like to put a spotlight on several NAV/SQL matters--things I consider important (maybe picking something from my book "The NAV/SQL Performance Field Guide"), not too detailed but still technical enough ..."NAV/SQL Quickies".

SQL and Memory Madness

"Memory" - or physical RAM - of a computer is something we consider naturally like the air we breathe - it's there, we take it. But just like our air is only breathable with the optimal mixture of Nitrogen, Oxygen & Co. also "Memory" is only usable if configured correctly.

At first it is necessary to understand the technical limitations of computers: a 32bit system could allocate 232 Bytes, that's 4 Giga Bytes - no more, no less. Out-of-the-box a MS Windows Operating System "splits" this RAM 50:50 - half of the Memory is assigned to the OS, the other half is granted to application.

Hence, any application can only use 2 GB of RAM at maximum - and of course, this also applies to the SQL Server! It is possible to change this standard assignment by enabling the /3GB (usually plus /PAE) switch in the system's boot.ini (or "Boot Data Configuration" in Win2k8) file; once enabled the OS will only use 1 GB and grants 3 GB (maximum) to applications.

Hmm ... so how is it possible to run 32bit machines with 8 GB and more? The trick is done via the SQL Server feature "AWE": Advanced Windowing Extensions. This is a technology which - simplified - locks memory ...

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About Jörg A.

Jörg A. Stryk has worked with Microsoft Dynamics NAV since 1997, version 1.20.

Being project-manager, consultant, administrator, developer or supporter on Microsoft partner-sites and NAV customer-sites, he has thoroughly explored nearly all areas of the application and its technology.

Since 2003 he is focusing on "Dynamics NAV & SQL Server Performance Optimization and Troubleshooting", founding his company "STRYK System Improvement" in 2006. As a freelance consultant, he is supporting Microsoft Dynamics partners and customers with their NAV/SQL projects worldwide.

His book "The NAV/SQL Performance Field Guide" (ISBN 978-3-8370-1442-6) is published in Europe, the United Kingdom and North America.

In recognition of his valuable participation in various NAV communities, he received the Microsoft award "Most Valuable Professional" (MVP) for MS Dynamics NAV in 2007, 2008 and 2009.

Visit Jörg Stryk at www.stryk.info or his BLOG http://dynamicsuser.net/blogs/stryk/

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