October 16, 2010 at 11:22 pm
what is AWE, which scenario we have to use awe
October 17, 2010 at 2:42 am
Did you try a google search? Lots of good information available if you look.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
October 18, 2010 at 8:53 am
It's October. Sounds like school is back in session.
If this is a school homework question, please don't expect us to do your work for you.
If this isn't a homework question, don't write it like one. Do some research first so you can ask more specific questions about the parts that you don't understand.
October 18, 2010 at 10:53 am
32-bit operating systems are only able to provide applications with a total of 4GB of addressable, virtual, memory (because 32-bit integers simply aren't big enough to manage larger allocation maps). Moreover, because Windows divides that addressable space up between the OS and each running application, applications (like SQL Server) are therefore only able to use a maximum of 2GB of addressable memory. And given that RAM is exponentially faster to access than disk, being limited to 2GB of RAM (when more physical RAM is available) quickly becomes a performance problem.
To overcome this problem, Microsoft created AWE, an improved API that lets applications address a larger pool of memory. The trick though, is that this memory isn't managed like normal, “dynamic,” memory and requires applications that wish to take advantage of it to make use of special API calls and access permissions. SQL Server, of course, was built to efficiently take advantage of Microsoft's AWE APIs, but it's that last little bit (the special privileges) that causes so much grief.
October 18, 2010 at 11:10 am
upstart (10/18/2010)
32-bit operating systems are only able to provide applications with a total of 4GB of addressable, virtual, memory (because 32-bit integers simply aren't big enough to manage larger allocation maps). Moreover, because Windows divides that addressable space up between the OS and each running application, applications....
Great post! Thanks
October 18, 2010 at 11:29 am
Note also that AWE can really only be used for some cache buffers. Much (if not most) of all the other data structures in SQL server for managing connections and I/O (network and disk) buffers are only able to exist in virtual memory.
If you are running out of resources due to increased activity associated with connections and overall concurrency then you better start considering upgrading to a 64 bit version.
The probability of survival is inversely proportional to the angle of arrival.
October 18, 2010 at 3:26 pm
AWE works in conjunction with PAE which extends the bus from 32 bits to 36 bits. You need PAE support in the OS to use Address Windowing Extensions!
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"Ya can't make an omelette without breaking just a few eggs" 😉
October 19, 2010 at 9:07 am
If you are speaking of a production sql server need here and are asking that question, you REALLY need to get a professional in to guide you. There will be MANY things said individual can help you set up, configure and monitor correctly.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
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