Fitzchak has all the details in our company blog.

Because I keep getting asked, this feature is available for the following profilers:

• NHibernate Profiler
• Entity Framework Profiler
• Linq to SQL Profiler
• LLBLGen Profiler
• Hibernate Profiler

This new feature detects a very interesting bad practice, write to the database from multiple session in the same web request.

For example, consider the following code:

public void SaveAccount(Account account)
{
    using(var session = sessionFactory.OpenSession())
    using(session.BeginTransaction())
    {
           session.SaveOrUpdate(account);
           session.Transaction.Commit();    
    }
}

public Account GetAccount(int id)
{
    using(var session = sessionFactory.OpenSession())
    {
        return session.Get<Account>(id);
    }
}

It is bad for several reasons, micro managing the session is just one of them, but the worst part is yet to come…

public void MakePayment(int fromAccount, int toAccount, decimal ammount)
{
    var from = Dao.GetAccount(fromAccount);
    var to = Dao.GetAccount(toAccount);
    from.Total -= amount;
    to.Total += amount;
    Dao.SaveAccount(from);
    Dao.SaveAccount(to);
}

Do you see the error here? There are actually several, let me count them:

• We are using 4 different connections to the database in a single method.
• We don’t have transactional safety!!!!

Think about it, if the server crashed between the fifth and sixth lines of this method, where would we be?

We would be in that wonderful land where money disappear into thin air and we stare at that lovely lawsuit folder and then jump from a high window to a stormy sea.

Or, of course, you could use the profiler, which will tell you that you are doing something which should be avoided:

Isn’t that better than swimming with the sharks?

Recently, we added a way to track alerts across all the sessions the request. This alert will detect whenever you are making too many database calls in the same request.

But wait, don’t we already have that?

Yes, we do, but that was limited to the scope of one session. there is a very large set of codebases where the usage of OR/Ms is… suboptimal (in other words, they could take the most advantage of the profiler abilities to detect issues and suggest solutions to them), but because of the way they are structured, they weren’t previously detected.

What is the difference between a session and a request?

Note: I am using NHibernate terms here, but naturally this feature is shared among all profiler:

• NHibernate Profiler
• Entity Framework Profiler
• Linq to SQL Profiler
• LLBLGen Profiler
• Hibernate Profiler

A session is the NHibernate session (or the data/object context in linq to sql / entity framework), and the request is the HTTP request or the WCF operation. If you had code such as the following:

public T GetEntity<T>(int id)
{
    using (var session = sessionFactory.OpenSession())
    {
         return session.Get<T>(id);
    }
}

This code is bad, it micro manages the session, it uses too many connections to the database, it … well, you get the point. The problem is that code that uses this code:

public IEnumerable<Friends> GetFriends(int[] friends)
{
   var results = new List<Friends>();
   foreach(var id in friends)
       results.Add(GetEnttiy<Friend>(id));

   return results;
}

The code above would look like the following in the profiler:

As you can see, each call is in a separate session, and previously, we wouldn’t have been able to detect that you have too many calls (because each call is a separate session).

Now, however, we will alert the user with a too many database calls in the same request alerts.

We have recently been doing some work on Uber Prof, mostly in the sense of a code review, and I wanted to demonstrate how easy it was to add a new feature. The problem is that we couldn’t really think of a nice feature to add that we didn’t already have.

Then we started thinking about features that aren’t there and that there wasn’t anything in Uber Prof to enable, and we reached the conclusion that one limitation we have right now is the inability to analyze your application’s behavior beyond the session’s level. But there is actually a whole set of bad practices that are there when you are using multiple sessions.

That led to the creation of a new concept the Cross Session Alert, unlike the alerts we had so far, those alerts looks at the data stream with a much broader scope, and they can analyze and detect issues that we previously couldn’t detect.

I am going to be posting extensively on some of the new features in just a bit, but in the meantime, why don’t you tell me what sort of features do you think this new concept is enabling.

And just a reminder, my architecture is based around Concepts & Features.

Originally posted at 1/7/2011

Because I keep getting asked, this feature is available for the following profilers:

• NHibernate Profiler
• Entity Framework Profiler
• Linq to SQL Profiler
• LLBLGen Profiler
• Hibernate Profiler

This feature is actually two separate ones. The first is the profiler detecting what is the most expensive part of the query plan and making it instantly visible. As you can see, in this fairly complex query, it is this select statement that is the hot spot.

Another interesting feature that only crops up whenever we are dealing with complex query plans is that the query plan can get big. And by that I mean really big. Too big for a single screen.

Therefore, we added zooming capabilities as well as the mini map that you see in the top right corner.

Originally posted at 1/7/2011

This is another oft requested feature that we just implemented. The new feature is available for the full suite of Uber Profilers:

• NHibernate Profiler
• Entity Framework Profiler
• Linq to SQL Profiler
• LLBLGen Profiler
• Hibernate Profiler

You can see the new feature below:

I think it is cute, and was surprisingly easy to do.

Uber Prof have recently passed the stage where it is mostly implemented using itself, so I just had to wire a few things together, and then I spent most of the time just making sure that things aligned correctly on the UI.

Originally posted at 11/25/2010

In a recent post, I discussed the notion of competitive advantage and how you should play around them. In this post, I am going to focus on Uber Prof. Just to clarify, when I am talking about Uber Prof, I am talking about NHibernate Profiler, Entity Framework Profiler, Linq to SQL Profiler, Hibernate Profiler and LLBLGen Profiler. Uber Prof is just a handle for me to use to talk about each of those.

So, what is the major competitive advantage that I see in the Uber Prof line of products?

Put very simply, they focus very heavily on the developer’s point of view.

Other profilers will give you the SQL that is being executed, but Uber Prof will show you the SQL and:

• Format that SQL in a way that make it easy to read.
• Group the SQL statements into sessions. Which let the developer look at what is going on in the natural boundary.
• Associate each query with the exact line of code that executed it.
• Provide the developer with guidance about improving their code.

There are other stuff, of course, but those are the core features that make Uber Prof into what it is.

The following features apply to NHProf, EFProf, L2SProf.

In general, it is strong discouraged to data bind directly to an IQueryable. Mostly, that is because data binding may actually iterate over the IQueryable several times, resulting in multiple queries being generated from something that can be done purely in memory. Worse, it is actually pretty common for data binding to result in lazy loading, and lazy loading from data binding almost always result in SELECT N+1. The profiler can now detect and warn you about such mistakes preemptively. More than that, the profiler can also now detect queries that are being generated from the views in an ASP.Net MVC application, another bad practice that I don’t like.

You can find more information about each warnings here:

• Data Binding & Queries Shouldn’t Mix
• Don’t Query From The View

WPF detection:

WinForms detections:

Web applications:

I recently got a bug report about an issue with EF Prof, apparently the application statistics would record the context being opened, but it wouldn’t show them being closed. The customer was rightfully worried about that, and wanted to know if this is a bug in his code or in EF Prof.

Not closing connections is a pretty bad idea, obviously, because you are going to hold a lot more server resources than you need.

But we couldn’t figure out what the problem was. On my end, I could see that EF Prof was recording the context close properly, but nearly the same code on the customer showed the problem. Note the word nearly. I asked for a repro of the issue, and once I had it, it took mere minutes to confirm that the problem exists.

Now was the time to find out why. The customer code was:

using(var context = new MyContext(new EntityConnection("name=MyConStr"))
{
   // do stuff
}

Now, what EF Prof tells you is a data context open & close are actually more accurately connection open & close. After some extensive study, I verified that it wasn’t my code to blame, there was a leaking connection here.

Checking a bit further, it became clear. We passed an existing connection to the context. When we dispose the context, the context asks: “Am I the owner of this connection?” And since the answer is no, it will not dispose it. It makes sense, you might want to use that connection for your own purposes, and it is pretty rude of the context to close a connection that it doesn’t own.

How can we resolve this? By giving the context the information to open the connection, but not the connection itself:

using(var context = new MyContext("name=MyConStr")
{
   // do stuff
}

This code will instruct the context to open its own connection, which it will know that it owns, so it can safely dispose it when it is disposed.

Look Ma, no leaks!

The following features apply to NHProf, EFProf, HProf, L2SProf.

The first feature is something that was frequently requested, but we kept deferring. Not because it was hard, but because it was tedious and we had cooler features to implement: Sorting.

Yep. Plain old sorting for all the grids in the application.

Not an exciting feature, I’ll admit, but an important one.

The feature that gets me exciting is the Go To Session. Let us take the Expensive Queries report as a great example for this feature:

As you can see, we have a very expensive query. Let us ignore the reason it is expensive, and assume that we aren’t sure about that.

The problem with the reports feature in the profiler is that while it exposes a lot of information (expensive queries, most common queries, etc), it also lose the context of where this query is running. That is why you can, in any of the reports, right click on a statement and go directly to the session where it originated from:

We bring the context back to the intelligence that we provide.

What happen if we have a statement that appear in several sessions?

You can select each session that this statement appears in, getting back the context of the statement and finding out a lot more about it.

I am very happy about this feature, because I think that it closes a circle with regards to the reports. The reports allows you to pull out a lot of data across you entire application, and the Go To Session feature allows you to connect the interesting pieces of the data back to originating session, giving you where and why this statement was issued.