Is it possible to disable output for lamba, SQL and IL panels. I would like to test performance of Linq queries using Linqpad, but I guess output for these panels might interfere with performance measurements...

Hi there

The SQL tab is fairly minimal in its overhead - I don't think it will make any difference to your performance stats.

The lamdba tab is populated (along with the results tab) only when you dump query results. When performance testing, you shouldn't dump queries because this will incur some overhead - instead, call ToArray() on them or enumerate them without writing anything.

Finally, the IL tab is populated only when you click it. So there's zero overhead there.

Regards

Joe

In one of my tests, I compare the results of 2 queries in one script, something like:

for( int i=0; i<1000; i++)
{
var q = <query1>.ToList();
}

for (int i=0; i<1000;i++)
{
var q2 = <query2>.ToList();
}

I used Stopwatch to measure time. Depending on which query was put first in code, the first one consistently run faster.

Do you get the same results in Visual Studio?

I'd expect the opposite - the first query that you run often takes the longest for a number of reasons. One being that it's incurring the cost of building the metamodel.

Joe

This post has been edited by JoeAlbahari: Jun 24 2009, 03:32 AM

Didn't try it in Visual Studio.. could it be, because of the SQL pane is building a string with all SQL statements, and the longer it gets, the more time it needs to add ? Easiest way to know for sure would be to be able to disable those panes, and see what happens.

I've made a preview build that lets you test this by theory by disabling the SQL translations. You can download it here:

www.linqpad.net/preview/LINQPad.exe

Then enter the following into your query before doing anything else:

LINQPad.ExecutionEngine.SqlTranslationsEnabled = true;

Joe

Finally had the time to test it, and it looks good...
I now get consistent results...
Thank you very much!!