Working with sharepoint large lists

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In a recent project, I had to get some information from the last sharepoint listitems inserted. I used foreach. Of course it is a bad idea. When the list grew (thousand of listitems)…the program worked as fast as a drunken turtle. Ok… As I was saying the data I needed was from the last x items inserted. So I replaced the foreach with a simple for:
count=10; (the last 10 items inserted)
for (int i = oList.Items.Count – count; i < oList.Items.Count; i++)

I ran the program and saw that the improvement was not what I expected, so I made a testProject to measure the execution time, for the foreach block code and the code above (with the simple for);

DateTime startTime = DateTime.Now;

chunk of code (for or foreach iteration)

DateTime stopTime = DateTime.Now;
TimeSpan duration = stopTime – startTime;

For large lists the foreach statement took forever. The for statement took from 5 to 30 seconds for 4000 list items.
The odd part was that in the for statement as I said before, i iterated through the last 10 items.
So for 10 items I waited some good seconds.
I googled for the truth and I found this interesting article.

So I found out the SPQuery is one of the best ways to work with large lists.

SPQuery query = new SPQuery(oList.Views[0]);
query.RowLimit = 10;
SPListItemCollection filteredList = oList.GetItems(query);
foreach (SPListItem item in filteredList)

I ordered the list Descending by their ID so i got the most recent 10 list items.
I measured the execution time. At the first run it took 800 milliseconds for 4000 list items. The next executions took only from 15 to 30 milliseconds.
I would say…it is at least a good improvement;
An easier way to create CAML queries is with U2U CAML Query Builder
I tried to use CAML query to get the max ID directly but I didn`t succeed. If someone reads this…:P and knows how please leave a reply.

Commerce Server 2009
Thank you,
Ing. Msc. Dan Gheorghe