Performance upgrade month 2

We use hibernate projections for a performance gain, and a very big performance gain.

Projections work this way: instead of loading real objects, we can tell NHibernate to load a specific property instead. So what we did was instead of loading an object with necessary objects pre-fetched, we build an ICriteria query and a projection for each property we need to display in the grid.

The gains are these:
1. We bypass hydration process, so that we get an array of columns, which we can databind to specific datagrid. Databinding process does not involve reflection code to extract data from objects, that's a side effect :)
2. We still have ICriteria interface to specify whatever filters we might need.
3. If one look at NHibernate projections, one would see that projections contains some nice things such as AVG, MIN, MAX, group by, COUNT etc. Do you see the possibilities? Tree views, additional helpful info for various reports, etc.

After making projections, so that it instead of loading 15k object graphs, we select only the properties we display in the grid, the time went down to 3-5 seconds from 15 seconds. That is, the performance gain was 3 to 5 times. That's alot.

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Disclaimer
We still have many problems with performance, but at the moment the UI responsiveness is satisfactory.

Here are the other problems we have and what we could improve:

1. We use Sourcegrid as our datagrid solution. It is much much better than System.Windows.Forms.DataGridView, since it provides a rather solid MVC separation and extensibility mechanism. However, it has it's own problems. Some of them might be solved easily, and some might be rooted deep in the sourcegrid itself.

Yes, you guessed it. One of the problems is performance :). SourceGrid has a problem of managing many cells (i.e. > 50k). Maybe that might be solved using VirtualGrid (a class in SourceGrid), have not delved alot into, so can not tell much, now.

P.s. for 15k objects default SourceGrid solution might add 3 to 5 seconds delay solely for constructing cells.

2. Every time we edit an object, we create and destroy a form. Forms could be cached and reused.

3. Object loading might be put on a separate thread, and instead of loading whole 15k rows, a thread could small chunk first, display it in grid, then load the other rows. This would increase UI responsiveness.

4. Sometimes some forms fail to open in 3 seconds. This happens when for example object Group has a collection of Students (count > 50), a collection of Companies (count > 50), a collection of other stuff, etc. All those collections we put into separate tabs in the form. We could make that each tab load the data incrementaly, and make the form responsive to user actions as soons as it has minimum amount of data. I.e. something like ajax thing, but for desktop. We might call it Desktop 2.0 :D