Ayende @ Rahien

Dathan Bennett commented on UberProf performance improvements, beware of linq query evaluation

Fri, 22 Jan 2010 17:40:02 GMT

@MF, ToArray() might be slightly faster, but list item access by index is constant-time, so the difference (if there is an appreciable one) is probably trivial.

MF commented on UberProf performance improvements, beware of linq query evaluation

Tue, 12 Jan 2010 03:51:05 GMT

would .ToArray() be slightly faster? or am i missing something?

david commented on UberProf performance improvements, beware of linq query evaluation

Tue, 05 Jan 2010 09:45:41 GMT

You asked 3 questions in your posting. I don't know the definitive answer to them. To aid those, like me, who come along in the future and read posts like this, it would be beneficial to see questions and answers -- rather than just questions. Comprendes?

Ayende Rahien commented on UberProf performance improvements, beware of linq query evaluation

Tue, 05 Jan 2010 05:41:29 GMT

Not sure that I am following you here

david commented on UberProf performance improvements, beware of linq query evaluation

Tue, 05 Jan 2010 02:26:41 GMT

@Ayende: so, are you going to fill in the the "just back from holiday, and brain slow to fire up" and the "too scared to comment in case I look foolish" amongst us? :-)

Konstan commented on UberProf performance improvements, beware of linq query evaluation

Tue, 29 Dec 2009 03:00:29 GMT

@John: would you be happier if your saw IEnumerable

Mike Chaliy commented on UberProf performance improvements, beware of linq query evaluation

Fri, 25 Dec 2009 09:57:22 GMT

@firefly, agree but LINQ full of such technics... It all about lazy. So I believe we already prepared for this klind of stuff.

firefly commented on UberProf performance improvements, beware of linq query evaluation

Fri, 25 Dec 2009 00:10:39 GMT

@Mike Memoization is a very powerful technique for performance optimization... Unfortunately it's something that could take awhile for an OO programmer to bend his head around to. Unless you are coming from a functional background :) Then it become your second nature.

Mike Chaliy commented on UberProf performance improvements, beware of linq query evaluation

Thu, 24 Dec 2009 22:28:59 GMT

Probably Rx has better solution compared to the ToList(). System.Interactive.dll has MemoizeAll method. It cashes results, but works in lazy manner. I have blog post about this [chaliy.name/.../system_interactive_new_and_usef...](http://chaliy.name/blog/2009/12/system_interactive_new_and_useful_linq_extensions_to_ienumerable)

John Chapman commented on UberProf performance improvements, beware of linq query evaluation

Thu, 24 Dec 2009 17:27:48 GMT

This is actually one of the reasons I find var to be mostly evil. var allows developers to ignore the real type. It changes the mind of thinking. The two pieces of code do VERY different things. Yet to an untrained eye it's not clear at all. Largely I blame var for this. If the type were explicitly defined in that statement I believe fewer people would make the mistake of misunderstanding how it is being used. I personally never use var in my code. That also means I never use anonymous types. I don't mind the extra typing involved. Typing doesn't take a long time. Forming the right solution to the problem is usually the much biggest cost, so typing cost is in the noise for me. Readability adds more. I realize I'm in the minority on this subject.

JJoos commented on UberProf performance improvements, beware of linq query evaluation

Thu, 24 Dec 2009 16:39:03 GMT

I agree with rik, and i wouldn't do it because the performance issues are probably in the first part.

Anthony Dehirst commented on UberProf performance improvements, beware of linq query evaluation

Thu, 24 Dec 2009 15:38:13 GMT

NumberOfStatements is statements.Count() - NumberOfCahcedStatements - NumberOfTransactionsStatements; I guess that you didn't do it as it would make the code a little messier as you couldn't use the inline constructor. I do hope that there is a better reason.

John St. Clair commented on UberProf performance improvements, beware of linq query evaluation

Thu, 24 Dec 2009 12:15:10 GMT

"group by" rather than count, and a join/group by for the agreegate number of statements?

Rik Hemsley commented on UberProf performance improvements, beware of linq query evaluation

Thu, 24 Dec 2009 11:25:58 GMT

I'd say the obvious 'optimization' would be to take counts of statements which are transactions, which are cached and which are neither. Something like this... long cachedCount, transactionCount, neitherTransactionNorCachedCount; statements.Each(s => { cachedCount += s.IsCached ? 1 : 0; transactionCount += s.IsTransaction ? 1 : 0; neitherTransactionOrCachedCount += s.IsCached || s.IsTransaction ? 0 : 1; } Not sure why you'd avoiding doing it, but I'm on holiday and my brain's not in gear. That's my excuse, anyway.