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Buffer Memory Size and SYS(3050)
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To
04/09/2009 10:26:34
Joel Whitehead
Ccs Central Computer Services Inc.
Thunder Bay, Ontario, Canada
General information
Forum:
Visual FoxPro
Category:
Third party products
Environment versions
OS:
Windows XP SP2
Miscellaneous
Thread ID:
01422660
Message ID:
01422664
Views:
97
Hi Joel,

VFP8 and earlier do have a problem handling memory bigger than 512MB. It usually happens when processing large tables and manifests itself with error message "Not enough memory for file map" (error 1150). It's currable by reducing memory for VFP buffers with SYS(3050).
SYS(3050, 1, 512*1024*1024)
SYS(3050, 2, 512*1024*1024)
Also try to call SYS(1104) after command that process large tables. It clears memory cache and buffers.

Check FAQ #8125 as well.

>I use Visual MaxFrame as my application framework and have applications written in VFP 6 through VFP 9 that I support. When I recently got a new workstation with 3 Gigs of memory, I found one of the programs that runs while setting up the environment for my applications started crashing (the program is called x3fbmem.prg). I guess this program helped improve performance back when computers had way less memory.
>
>Anyhow, the fix they recommend is the following which sets the foreground buffer to a maximum of 100MB:
>
>* enforce a maximum of 100MB
>lnAvailableMemory = MIN(m.lnAvailableMemory,100000000.00)
>
>=SYS(3050,1,m.lnAvailableMemory)
>
>My question is this: isn't 100MB incredibly low? If I run VFP without loading an application framework (just default VFP) on a PC with 1GB of memory (and nothing else running), it sets this buffer to over 800MB. And on my PC with 3GBs of memory, I get almost a 1.5GB buffer by default. Isn't chopping this down to 100MB as my Visual MaxFrame app loads just going to bring performance to its knees? Or am I misunderstanding what this is doing.
>
>BTW, I did try the Visual MaxFrame messageboard, but have not had a response since August 12th.
>
>Any help in understanding best practices for SYS(3050) would be greatly appreciated.
>
>Thanks!
>
>Joel
--sb--
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