Al Priest’s Blog

Everytime I try and get Ayende’s NHibernate Query Analyzer to work I seem to encounter some weirdness. Here’s what I did to get it running this time.

1. Download the version appropriate to your version of NHibernate. For me, that was 1.2GA
2. Create a new app.config file, and into it place just the NHibernate configuration section and the appropriate settings. Note that when I tried it, NQA didn’t like the <hibernate-configuration> notation for the hibernate section, instead I had to change it to use the <nhibernate> notation.
3. Load up NQA and start a new project.
4. Add the app.config file you created and the assemblies which contain your embedded HBM files.
5. Hit Build Project. IMPORTANT! If you see any errors, then quit NQA, fix the errors, and start again. If you leave NQA running and try again you’ll see the same error message as it seems NQA doesn’t close the old app domain properly.
6. If all that works, then your home dry. File, New Query, and off you go. Brilliant tool once it’s going.

Mozilla has launched an interesting labs add-on for Firefox called Ubiquity. It’s a productivity tool for passionate users, as the Scobleizer writes “It’s not for non-passionate Internet users. They won’t get it.“.

Download it, read the tutorial, have a play, extend it, and increase your productivity )

UPDATE 8/Sep/2008: I’ve creaed a ubiquity command for my Pub Finder, to install it, visit my install page. To activate it open up Ubiquity and type pubfinder and hit enter to see the pubs.

From Wikipedia, “Kaizen is a Japanese philosophy that focuses on continuous improvement throughout all aspects of life”. After a review of our systems from a software coach in the department, I decided to instigate a weekly Kaizen session for the whole dev team. (I first heard of the term Kaizen a few years ago when my then department manager spoke of it and I guess now I understanding what he was meaning – thanks Marc!)

The plan is to spend 1 to 1.5 hours a week pairing with another dev investigating a certain area of the code trying to improve it with no strict deliverables. The hope is that the tools and techniques we use in these sessions will become integral to our daily work and code quality will measurably improve.

To feed into these sessions I created a backlog of features to be investigated. These were stuck on cards on the whiteboards for the pairs to select from. Anyone is free to submit a card for an area of code they’d like to look at.

Here’s a few of the cards I created for week 1 to start us off.

Method foo has a Cyclomatic Complexity of 28, aim to reduce it.
Using NDepend i’ve been looking at some metrics across one of our projects. NDepend gives you so much data that it’s easy to be overwhelmed so I chose Cyclomatic Complexity. This found a single method in our code rated at 28 – that’s to say, there are 28 paths through that method. Although we have 13 unit tests for this method we aren’t testing every line of code, and there’s probably some refactoring that can be done.

Class foo has test coverage of 72%, aim to increase it.

Using the TestDriven.net Visual Studio plug-in with NCover we monitor code coverage of our unit tests. 72% is great, but quite a lot of our code has over 95% coverage so this class needs more testing.

There are 8 unit tests currently marked as [Ignore], without simply deleting the unit test, aim to reduce that count.

This is pretty self explanatory. I don’t know why the tests were marked with the Ignore attribute, but they are, and they shouldn’t be.

I was shown today how by using the Duplicates.NET build runner in our Team City CI server it can automatically identify duplicate code across the system. Despite the fact that this project was a greenfield development we’ve still ended up with some duplicate code in need of an Extract Method refactor. Metrics from these reports will feed into our Kaizen backlog.

For those interested, the end result of the above 3 cards was 12, 74% and 4 respectively, so i’m happy we’ve improved the code and got familiar with the tool set.

Had a problem with NHibernate Lifecycle events recently where they appeared not to be firing when I was hitting ISession.Save(entity). After some investigation I finally realised that if you create a new entity, then query NHibernate it may implicitly persist the transient object during a Flush. When it does this any interceptors will be fired at *Query time* thus preventing them from firing when you explicitly call SaveNew. This is by design of NHibernate to ensure the query results are always valid, and is documented here.

I’m not sure how long this has been around, but it’s just popped onto my radar:

MapTube – a place to put maps

It’s a collection of Google Maps overlays most of which display demographics, but this one caught my eye – it’s a map showing the actual location of the London Underground lines, like the Way Out Map.

I love my Mac, but this morning I found the one reason why the glossy UI isn’t always that great – since upgrading to Leopard Apache hasn’t been working on localhost but according to the System Preferences panel all is well.

A quick Google and I found several references to apachectl which is the server control interface. Running “apachectl -k restart” at the prompt returned


(13)Permission denied: make_sock: could not bind to address 10.0.0.1:80
no listening sockets available, shutting down
Unable to open logs

There were 2 clues – the one which I ignored at first about permissions (“i’m logged into an administrative account so it can’t be permissions… doh”), and the reference to the logs. Turns out that on my installation of Leopard the log file folder had failed to be created and thus Apache wasn’t starting.

If you’re having these problems, try the following.

sudo mkdir /private/var/log/apache2
sudo apachectl -k restart


Hey presto everything back under glossy System Preference panel controls once more, and just PHP to get working again.

The system i’m working on at the moment recently went into systest and we found a couple of database errors relating which NHibernate was throwing an exception of

Unexpected row count: -1, expected 1

This wasn’t happening on the development system so we took the apparently faulty database from systest and ran it in dev. No errors. This all pointed to an environment issue and after a little checking we discovered that the NOCOUNT setting was different between each database server.

But hang on – when we create the ISession we were creating an IDbCommand and setting NOCOUNT OFF, surely this was enough? Running a SQL profiler I spotted sp_reset_connection commands being executed almost every other statement from NH. This was resetting the NOCOUNT setting and thus it inherited it from the server setting all the time.

Comparing another system’s NH provider versus the one in this system, and I discovered a subtle difference. System A creates an IDbConnection itself and passes it into NH, whereas system B lets NH generate its own connection. It seems that the ConnectionProvider in NH tracks where the connection was created and aggressively releases it if it was internally created.

So my advice is always pass your own connection to NH which allows for better testing and removes the possibility of this happening. Spring.net was a very quick candidate for doing this DI for me.

UPDATE: Since writing my post, i’ve found that providing your own connection prevents NHibernate using the second-level cache so the better solution is to write your own implementation of ConnectionProvider which calls the NOCOUNT OFF on new connections and wire that up in your .config file. Here’s my implementation.

UPDATE 2: I’ve been writing a Linq to SQL app this week, and it turns out that it also requires NOCOUNT OFF, otherwise you get a “Row not found or changed” exception of type ChangeConflictException with a single ObjectChangeConflict object, which has 0 MemberConflicts!

The recent ‘Take 2′ Apple TV update has saved the small square box under my telly from EBay. 1080p output, rental HD movies, and now streaming internet radio have given it a real lease of life.

Now I realise that it’s meant to be just a media extender, but as it’s just a Mac under the hood i’m hoping we get an SDK soon, then we could have a few new features like

- RSS browsing sync’d with Newsgator with an iTunes-sourced soundtrack
- London Underground line information without needing my Mac or digital text
- Optionally playing music without displaying the flipping artwork

This is surreal. From Improv Everywhere… “On a cold Saturday in New York City, the world’s largest train station came to a sudden halt. Over 200 Improv Everywhere Agents froze in place at the exact same second for five minutes in the Main Concourse of Grand Central Station.”

From CoolHunting

“By installing Eye-Fi software on your computer and using the 2GB card in your camera in place of a regular SD card, you can use your home WiFi network to automatically upload photos via easy-to-use software. It’s really that simple.”

Slight downside that you have to install software – I hope this software can be downloaded for free from their website for those times you’re in a cafe, or perhaps the software only enables extra features like uploading to Flickr etc.