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Re: Oracle 10g on Windows 2003 x64 Memory Useage

From: Charles Hooper <>
Date: Sun, 12 Aug 2007 12:30:03 -0700
Message-ID: <>

On Aug 10, 7:28 am, Charles Hooper <> wrote:
> On Aug 9, 6:14 pm, "Paul Linehan" <plinehan__A_at_T__yahoo__D.OT__COM>
> wrote:
> > I have read quite a few of your posts and I think
> > that:
> > a) you know what you're talking about
> > and
> > b) you genuinely try to help people.
> > I hope that this info can help you and/or others.
> > ForWindows, there is a nifty/cool/rad/awesome(for Yanks
> > only) - (choose term which hasn't gone out of fashion, or
> > better yet, the one which has come back into fashion!!)
> > Go towww.sysinternals.comandgo for procexp (process
> > explorer).exe - it gives more reliable results than
> > theWindowsperformance monitor.
> > Inconsistent numbers should not happen. The site also
> > has a number of other useful bits and bobs for anyone
> > concerned with performance.
> > Paul...
> Thanks for the suggestion - I have not experimented with that utility
> in quite a while.
> Looking at the page file on the hard drive, it is currently at
> 3,199,488KB, with an upper limit hard coded at 4,092MB (4,190,208KB).
> Process Explorer:
> Commit: 13.6GB (roughly 14,260,634KB)
> Commit charge current: 14,254,748KB
> Commit charge peak: 18,208,828KB
> (recorded roughly 60 seconds after the above)
> Task Manager:
> PF Usage: 13.5GB (roughly 14,155,776KB)
> Commit charge total: 14,258,808KB
> Commit charge peak: 18,208,828KB
> Physical memory total: 16,772,124KB
> " " available: 3,798,000KB
> Comparing the numbers between Process Explorer (now a Microsoft
> product) and Task Manager onWindows2003x64 are very consistently
> inconsistent.
> 16,772,124KB
> - 3,798,000KB
> -------------
> 12,974,124KB physical memory in use
> +14,254,748KB page file in use
> -------------
> 27,228,872KB total memory usage
> -or-
> 12,974,124KB physical memory in use
> + 3,199,488KB actual page file size
> -------------
> 16,173,612KB total memory usage
> I *suspect* that the problem has to do with the memory page size being
> 4096KB for applications using large page support, rather than the
> expected 4KB memory page size. There is probably a bit of code inWindowsthat does not yet recognize the change (this is a new feature
> forWindows), either that or Microsoft should patent the approach of
> jamming 14,254,748KB of data into a 3,199,488KB file. :-)
> Charles Hooper
> IT Manager/OracleDBA
> K&M Machine-Fabricating, Inc.

A member of this forum suggested to me a different possible cause for the inconsistency of the page file usage numbers shown in the Task Manager and Process Explorer. So, I used Google to search Microsoft's site for additional clues.

It appears that on Windows XP and Windows 2003 Server that the "PF Usage" statistic (not present in previous versions of Windows) is NOT page file usage. Instead, it is total virtual memory usage for Windows and all applications, which includes both RAM and data stored in the page file (32 bit applications on 32 bit Windows have access to either a 2GB or 3GB virtual memory range). The "PF Usage" statistic is esentially the same as the "Commit Charge: Total" statistic, which is the size of the virtual memory in use by all processes.

References: "Commit Charge: Total - Size of virtual memory in use by all processes, in kilobytes." Commit Charge (K): Memory allocated to programs and the operating system. Because of memory copied to the paging file, called virtual memory, the value listed under Peak may exceed the maximum physical memory. The value for Total is the same as that depicted in the Page File Usage History graph." "PF Usage: The amount of paging file being used by the system. If your computer is running near the maximum, you can increase the page file size." "Commit Charge Provides information on the total memory used by the operating system. Total lists all physical and virtual memory currently in use. Limit lists the total physical and virtual memory available. Peak lists the maximum memory used by the system since bootup." "To see how much virtual memory your Windows 2000 Professional-based computer uses, start all applications and use Task Manager to see the Peak Commit Charge value. This value appears in the Commit Charge box on the Performance tab. Commit charge is the number of pages reserved for virtual memory that are backed by the paging file. Peak committed memory is the highest amount of virtual memory (in bytes) that has been committed over this sample. To be committed, these bytes must either have a corresponding amount of storage available on disk or in main memory. Compare this value against the size of the paging file to determine whether the paging file is sized appropriately." Shows "Mem Usage" where later versions of Windows show "PF Usage". Windows Vista shows "Memory" in the same location. The "Page File" statistic in Vista, which is currently 1471MB (roughly 1,507,328KB) on my laptop, matches up very closely with the value 1,512,852KB reported by "Commit Charge Current" in Process Explorer.

Note that there is a bit of inconsistency in the above quotes, which are all from various Microsoft sources. From the above, using the numbers that I previously posted:

 14,254,748KB  (PF Usage, Commit charge total)
-16,772,124KB  (Physical memory total)
+ 3,798,000KB  (Physical memory available)

  1,280,624KB (Calculated page file size in use)

This seems to make a bit more sense, as the calculated page file in use falls below the hard coded maximum page file size of 4,190,208KB.

Thanks to Paul Linehan for suggesting the Process Explorer utility, Howard Rogers for providing a reference to a related Oracle bug, and Yong Huang for suggesting that there is possibly a different explanation for the inconsistency.

Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc. Received on Sun Aug 12 2007 - 14:30:03 CDT

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