I am investigating for how many time it takes for a particular operation to complete. The operation is like the following:
Parallel.ForEach(items, item => SaveScheme(item));
The SaveScheme method works with a database: executes some queries and works with the information. The amount of elements in items collection can be big enough.
When I run this operation, it takes about 20-40 seconds to complete. But when I run it with a profiling turned on, it takes only 3 seconds!
I didn't find any information about this problem. My only guess is that with profiling Parallel.ForEach creates more threads than without it, but I don't know for sure, and even if it's true, I don't know what to do with it.
So, why is that happens and how can I archieve this performance when I run the application without profiling?
UPD. Parallel has nothing to do with this: I tested with simple foreach instead and the operation still completes in 3 seconds!