Undo Enumerable.AsParallel(), going back to serial mode

Question

Assume you have a LINQ query like

source.AsParallel().Where(expensiveOperation).Select(cheapOperation)

I suppose in this case Select also runs in parallel execution mode. Maybe it's just a cheap operation like i => i*2, so is there a way to stop parallel execution at a point of querying with chained methods?

(maybe like .AsParallel().Where(expensiveOp).AsSerial?().Select(cheapOp)?)

I belive PLINQ is smart and executes the `Where()` together with the `Select()`. So, even when `Select()` is cheap, you probably don't need to force it to be sequential. But you'll have to measure that for yourself. — svick, Dec 24 '13 at 00:22

score 10 · Accepted Answer · answered Dec 23 '13 at 22:38

10

The operation you're looking for is AsSequential.

source.AsParallel().Where(expensiveOp).AsSequential().Select(cheapOp)

answered Dec 23 '13 at 22:38

Douglas

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looks like I was wrong on vocabulary haha. Thanks for noting. I literally looked for `AsSerial()` in docs for a few mins. – ahmet alp balkan Dec 25 '13 at 05:14

Undo Enumerable.AsParallel(), going back to serial mode

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