The Good, The Bad and The Ugly.

I've been real busy with non load testing stuff at work and haven't had much of a chance to continue playing around with VS2008 for LT purposes but I have found out some interesting stuff.

The Good:

You can specify the data store (either SQL Server or SQL Server Express) for storing all the individual hits from web sites and then query that information which renders that I was doing in the earlier blog post as moot. Yay! By default, VS2008 TSTE keeps these results in SQL Server Express that is installed when Visual Studio is installed. It's pretty cool that you can choose to store results in another location for historical reasons.

Looking around the data in the tables I'm not sure if you can group page hits together by transaction ID. But, I haven't had much of a chance to play around with querying data and am not for sure if this is the case. If that is the case, I can still use a method similar to a previous blog entry for collecting the metrics myself for catching page response time as it relates to individual transactions. A bit of a PITA but fantastic that I can do it if I want. Yay for a flexible framework that allows me as a test with development background to run around and do this kind of stuff.

One thing I know for sure though is with the ability to query the databases I should now have the ability to crunch the numbers for transactions and now get average, standard deviation, hit counts, etc. The idea is that in a nicely controlled environment I should be able to generate an automagic report for day to day automated load test execution and be able to do something like a mean population comparison of transactions times from one test to the next and pick out statistically significant deviations for alpha = 0.05. That'll be kinda neat if it works out.

Now that I think about it, the VS2008 tool should have been reporting these metrics all along. LoadRunner defaults with basic statistical information and VS2008 should report the same as well. It is kind of annoying, but I like the fact that I have a published schema that I can use to extract the information that I want (see link to schema information for VS2008 further down below). So, another plus in the LoadRunner column. [I might really like the VS2008 product, but I do have to be fair in my comparisons of Pro/Con of VS2008 versus LoadRunner.]

I wasn't able to use the statistical modeling at my previous employer because our systems were just too large with too many variables involved. We had communication from the web server to the database server (which was on the same switch so not much of a problem) but we also had a bunch of communications to the Host. The Host was required for testing the web sites and was actually hitting production systems that merely disregarded the requests and sent back bogus results so that we wouldn't kill the mainframe.

Many years ago I tried to get rid of this variability by writing what I called a "parroting proxy server." It was a bit of C# code that was essentially a protocol agnostic proxy server that would pass messages from point A to point C where the intermediate Point B was the proxy. It would store responses with a in memory hash and if the same request was caught being requested it would go ahead and send back the hashed response to eliminate the variance that we would see. It worked out pretty good but we never got around to implementing it. Unfortunately in a Fortune 50 company the bureaucracy can be too great and with Empire Building as it is the other managers didn't see what was in this for them and I suppose I didn't do a very good sales job. So be it.

To flip the switch to log all data so that you can query the data for fun and profit is to modify the "Timing Details Storage Property" in the Run Setting node of the load test editor to "All individual details."

And unlike the LoadRunner database (AFAIK, I could be wrong!), this schema is published with all sorts of handy information located at http://blogs.msdn.com/billbar/articles/529874.aspx. How great is that?

The Bad:

I haven't had enough time to continue my little load testing adventure. I'm finding that my new employer needs to update their processes as it relates to building production final machines. The current steps are extremely painful. But I suspect it'll be just fine in the long run as I've had some experience in this in the past and now that this process can be fully automated and integrated into our build process to be painless.

The Ugly:

Ok, this is ugly. I tried to write a simple script to augment some stuff that I did last week only to find that I couldn't bring up an instance of IE with the Web Recorder active and it is frustrating as hell. I found several posts that essentially say that the "solution" is to delete your login profile and start again. Yeah, that really sucks, Microsoft. I'd like to have a solution that doesn't require me to blow away my profile and have me spend hours getting my desktop back into the shape that I like it. That is a real PITA for sure.

I have three profiles on my machine and I can only generate recorded web tests with one of these profiles. I blew away one of the smaller profiles (not my main profile where I have 2.5+ gig of files) and gave it a try and it was no-go. I still could not record web tests. Yeah, that is bad. Very bad.

I'm not sure what the solution on this is going to be. In the short term I'm going to have to use my Administrator login to create scripts and then xfer that over to my main login script. How craptacular is that? Once I get some free time I'll have to look into this further but I am dreading it. No fun!

Here are some MS blog entries related to the problem. Perhaps they could help somebody else but I haven't seen any love for me, yet.

http://blogs.msdn.com/mtaute/archive/2007/11/09/diagnosing-and-fixing-web-test-recorder-bar-issues.aspx
http://blogs.msdn.com/edglas/archive/2007/11/01/web-test-recorder-bar-not-showing-up.aspx

It appears that Fiddler2 might be an interim solution from what I read here in this MS blog post located at http://blogs.msdn.com/slumley/pages/enhanced-web-test-support-in-fiddler.aspx.

A PITA? Sure, but it beats not having any solution at all. Fiddler is purt near cool and I've "fiddled" with it a little bit and it is nifty.