Comments on: Today’s fun: VFP Memory Limitation

By: Rick Schummer

Rick Schummer — Wed, 11 Nov 2009 01:04:04 +0000

No, the 2GB limit is what it is in all versions of Visual FoxPro and FoxPro. Advantage Database Server does manage to open DBFs larger than 2GB and there is always the ability for VFP to use remote data (MySQL, SQL Server, PostgreSQL, etc.)

By: Anonymous

Anonymous — Tue, 10 Nov 2009 18:49:35 +0000

Hi Rick.
Are there any FoxPro versions that allow a table larger than 2gb? We are currently using version 6.
Thanks!

By: Suganya

Suganya — Thu, 17 Jul 2008 18:02:00 +0000

Okay. Thanks Rick. I'll give a shot at splitting the cursor. (It's just not gonna be easy though:-)

Rgds,
Suganya

By: Rick Schummer

Rick Schummer — Wed, 16 Jul 2008 19:57:32 +0000

Suganya,

The 2GB limit is a hard limit for DBF files, which cursors are. The memory limit will not fix this. Only reducing the amount of information into to cursor will help avoid the limit. You can reduce the number of columns, the width of the columns, or the amount of rows stored. You can also partition the cursor into two cursors.

My recommendation is to visit a site like Foxite.com to post the problem and get help from lots of smart VFP developers.

By: Suganya

Suganya — Wed, 16 Jul 2008 15:06:00 +0000

Hi Rick,

I'm pretty new to foxpro and have been asked to look into some issues that have come up on a couple of existing foxpro 8.0 applications, that were developed around 10 years back or so.

These applications load data from several text files into a sql db. A lot of complicated processing happens within the program, with the use of several cursors. This load program fails with the following error -

Error (1190) in RULE105_rule105 on line 2982 message File d:\empower\temp\2moo00bz.tmp is too large

So, I looked into the temp folder and found that it is creating temp files greater than 2 gb, while doing inserts into some of the cursors. So, I did some googling and read that decreasing the buffer foreground memory might help. So I went ahead and changed the values as follows.(in the idea that foxpro might create smaller .tmp files) It actually worked for one of the apps. But the issue still exists with another app. I've been on the internet for the past few days trying to find articles related to how foxpro does memory mangement and I bumped into your blog. Could you tell me if this approach absolutely does not makes sense at all? or if there is any way we can tell foxpro to create .tmp files less than 2gb? Or if you have any suggestions?

Existing Values:
Buffer Foreground Memory: 536870912
Buffer Background Memory: 134217728

Changed Values:
Buffer Foreground Memory: 268435456
Buffer Background Memory: 67108864

Also tried to reduce it further to the following. But it's not helped so far.

Buffer Foreground Memory: 67108864
Buffer Background Memory: 16777216

Thanks,
Suganya

By: Rick Schummer

Rick Schummer — Fri, 11 Jul 2008 12:34:59 +0000

I had to look up the setting I am using and it is 64MB. If I recall correctly I used Mac’s findings to determine the setting. Those were great articles, thanks for mentioning it here.

By: woody-prolib

woody-prolib — Fri, 11 Jul 2008 12:11:00 +0000

Such a calculation routine is absolutely useless. Set the fore- and background memory to a fixed value of 32 Mb (yes, not more!) and VFP wil hum along. You may want to dig out the speed tests from Mac Rubell in FoxPro Advisor from 1997/1998, they are stil valid. More memory isn’t always better. Remember: the VFP dataengine was developed when we had only a handful of RAM and we stil have been working with Gigabytes of data.