[RESOLVED] Preventing OutOfMemoryExceptions

Hello all,

I'm loading a particulary large database (access 2003, oledb) into a few seperate DataGridViews in my program (64,000 records in one table, 120,000 records in another, each record with >40 255-character strings), and am starting to get System.OutOfMemory exceptions, usually during mundane tasks (for instance, the code below, simply determining the minimum value in one of the the columns).

Code:

---

int minimumID = -10000;

foreach (DataGridViewRow row in dEditMain.Rows)
{
    if (row.Cells[1].Value != null)
    {
        if ((int)row.Cells[1].Value < minimumID)
            minimumID = (int)row.Cells[1].Value;
    }
}

---

I've tried replacing the foreach with a for loop and even breaking it into several loops, under the (apparently mistaken) apprehension that the foreach was loading the entire list of DataGridViewRows into memory. It didn't help.

Some of the other loops also use int.Parse(row.Cells[1].Value.ToString()) instead of casting (a holdover from a previous version, in which the numbers were stored as strings). Would replacing these with (int)casts aid the memory situation?

Watching the "Memory (Private Working Set)" column in task manager, the process seems to be allocating 20MB just running, 490MB after the first table is loaded into memory (via a Fill() command), 850MB after the the second is loaded, and shooting up to 1350MB and then failing when a few loops similar to the one above are run.

What are the best-practices for dealing with something like this? Would compiling for x64, or for .Net 3.0, help?

Any help or suggestions would be appreciated. Thanks,
Qu.

The solution is simple - do not hold that much data in memory. There's no practical need for that since no user would operate that amount of data. Try to reconsider your user interface (or re-design it). Would you want to plow your way through 120 thousand records in a datagridview? No, I don't think so.
If so, why loading it at all?

I think you're going to have to manually implement pagination and then do things like find the MINimum value by querying the data directly. (Manually implementing pagination means you ask the database how many records there are, load only a few, add a label for "pages" and then load the appropriate pages accordingly)

Compiling x64 may help - but only if you're sure all your customers will be on a 64 bit OS and have more RAM than will be needed.