I attended your session at the PDC09. Great talk!
I found it very interesting, so when they asked me to do a session at MS DevDays in the Netherlands I decided to talk about LINQ and PLINQ.
I hope my crowd also will be inspired by it.

In your example, PLINQ runs your operations in parallel. Each operation opens a connections to the database. But, it seems that by opening multiple concurrent connections, you group update does not get any faster – probably because the database takes a lock and serializes the operations. Does that help clarify things?

Should I change Sql options to connections ?

Can you tell me If I use PLINQ to communication with DataBase, Should I expect better result than LINQ or PLINQ is only applicable to the in memory operations ?

Thanks for response again

Perhaps SQL2008 only executes one of the updates at a time. You can try what happens when you run six processes concurrently, with each process invoking the stored procedure.

bool[] result = new bool[personCollection.Count];
result = personCollection.AsParallel().Select(x => data.UpdatePerson(x)).ToArray();

Why PLINQ is not the right choice?
When I run stored sprocedure, sp_who2 on SQL2008 I see six connections, but all them have sleeping status…

Thanks for replay

I’m tried to update rows using PLINQ (I used Parallel.ForEeach() too), but I don’t have good results.
And Parallel result is worse then Sequential…

What I have to do, that to have parallel result better ?