A Little on LINQ

Recently I was involved (only a little) in preparing some of the Visual Studio Launch content for the February 27th launch event (and subsequent worldwide events). During the preparation we held "train-the-trainer" meetings where people who would be presenting launch sessions around the world could learn more about the sessions and ask questions. During one of these TTT events a question was raised about a LINQ demo that was written for a session named "Breakthrough Software Development Challenges with Visual Studio 2008".

The Question

Is there a performance impact to joining result sets in LINQ from two different data sources?

This question came up because this is exactly one of the scenarios we demo. Here is my rendition of the demo.

The Answer

I talked to the language teams and this is the truth of the situation.

For cross-domain joins you typically have the choice between really lousy performance or a runtime error – and generally you should prefer the latter!

The original source of the query gets to decide how the query gets executed. If the source is a LINQ to SQL table, for instance, it will simply look at anything it gets joined with, and throw an error if that is not another LINQ to SQL table, entity collection or query result.

If you go the other way, however, and join an in-memory collection (such as the descendents of an XElement, as in our demo) with a LINQ to SQL table or query result, then you are in trouble: It will enumerate the table into memory and do the join on your machine (Yikes!).

The general guidance is: don’t do cross domain joins!

Let me qualify a bit: I am talking specifically about a “Join” operation on large data sources in different domains. There are several things you can still do to work sensibly across domains, such as:

• Query the remote (e.g. LINQ to SQL) data first to yield a small enough result that it makes sense to pull it down and join locally
• Use the Contains() method on LINQ to SQL data, which will take small local collections and actually send them to the db as an IN expression in the generated query

The upshot is that one still has to be aware of the cross-domain joining and manage its impact as an application programmer.

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Upcoming Events I am Speaking At

In March and April I am actually a bit busy espousing prolifically about topics near and dear to me. I have a couple internal Microsoft events I am speaking at - one to what we call our Inner Circle Partners, and the other to System Integrators. In both events I am speaking on Visual Studio Team System and Application Lifecycle Management. The topics I am covering internally include topics I am speaking on in public venues as well.

VSLive! San Francisco

At VSLive! in San Francisco, Stephanie Saad and I will be presenting the ALM and Development Process track during the Microsoft Day (Monday, March 31, 2008).

Here is the track detail:

VM1 A Lap Around Visual Studio Team System 2008
Stephanie Saad
10:15 a.m.
In this demo-intensive session you will be exposed to many of the new features in Visual Studio Team System 2008. This session cover everything from Team Foundation Server for project management, work item tracking, version control and build support, to integration with Microsoft Project and Excel, unit testing, code coverage and code metrics, database projects, to Web testing with AJAX support and the new user-pace load testing. You will leave with an understanding of how Visual Studio Team System 2008 can be your organization’s Application Lifecycle Management (ALM) solution, and enable you and your team to collaborate and communicate to ensure software quality and provide visibility into the development process.

VM4 Improving Team Development
Doug Seven
11:45 a.m.
Do you build software alone? In today's world, software development is done by increasingly larger teams made of people with different skill sets, including project planning, functional definition, development and testing. As teams grow larger there is a greater need for tools to enable the communication and collaboration that is necessary to deliver high quality software effectively. In this session you will learn how to function as a collaborative team using Visual Studio Team System 2008, including process templates, work item tracking, version control, and reporting. Whether you are team that values Agile process, one that prefers CMMI, or any other process, this session will apply to you.

VM7 Create Better Software
Doug Seven
3:00 p.m.
You want to ship better software. Ultimately you measure your success by determining the quality bar that is acceptable, and the risk mitigation that is appropriate for your project or organization. While some projects require high, stringent quality levels, others can be more forgiving. In either case, you want to ensure your software meets and exceeds its quality bar, and all risks are addressed as needed. In this session you will learn about the quality assurance benefits of Visual Studio Team System 2008, including unit testing, code coverage & metrics, performance profiling, Web testing and load testing (including AJAX support).

VM10 The Future of Application Lifecycle Management from Microsoft
Stephanie Saad
4:30 p.m.
We are well underway developing the next release of Visual Studio Team System, code name "Rosario." In the next release, you and your team will benefit from enhanced communication and collaboration that enables you to match your development efforts with the needs of your business. Your team will benefit from improvements in work item tracking, dependency identification, historical debugging, test impact analysis, stand-alone debugging, and the addition of a stand-alone manual test runner enabling you to extend out your testing efforts easily. This session will include demos of some of the key improvements in Visual Studio Team System that are planned for the Rosario release.

I would love to see you there and get a chance to chat.

Irish Microsoft Technology Conference, Dublin, Ireland

The day after I hop a plane and fly to Dublin, Ireland for the Irish Microsoft Technology Conference (IMTC), a 2-day conference run by the developer community in Ireland that is supported/sponsored by Microsoft DPE Ireland. I am very excited about this event. This is a combination technical event and one of our worldwide launch events (Windows Server 2008, Visual Studio 2008, SQL Server 2008).

Here are my sessions:

15:15 - 16:30 Reach End Users With Next Generation Web Applications (Doug Seven)
Reach End-Users With Next Generation Web Applications is presented by Doug Seven

10:00 - 11:15 A Lap Around Microsoft Visual Studio Team System 2008 (Doug Seven)
In this demo-intensive session you will be exposed to many of the new features in Visual Studio Team System 2008.

15:15 - 16:30 Improving Team Development with Microsoft Visual Studio Team System 2008 (Doug Seven)
Do you build software alone?

11:30 - 12:45 Breakthrough Software Development Challenges with Visual Studio 2008 (Doug Seven)
Explore all the new Visual Studio 2008 features!

If you can make it to this one...you can buy me a pint :)

I think I get to lay low for the rest of April and May (unless I go to Visual Studio Connections in late April).

TechEd 2008 Developers Conference

From June 3rd - 6th I will be at the TechEd 2008 Developers Conference (OK, I will be in Orlando from May 31st - June 14th, for both the Developers and the IT Professionals Conferences...but I digress). I am only presenting one session because I am also the Co-Track PM for three tracks (along with Erika, who also has a fourth track). That should keep me pretty busy...if you see me and I look like a zombie...buy me a triple grande nonfat latte...it will make my day!

Here is my one session:

Build Better Software: Tips and Tools to Improve Your Applications
You want to build better software. You want the applications you build to be better, cheaper, and faster to release. One of the most costly stages of software development is finding and fixing bugs. What if you could find the bugs and fix them nearly immediately? In this session, learn tips and tools you can use with Microsoft Visual Studio Team System 2008 to determine code complexity, validate the capabilities of the application, and understand the overall quality of the software you are building. If you want to improve the code you write then don’t miss this session.

The date and time are TBD.

OK...that's enough to keep me busy for a while. I hope to see you at one or more of these events.

D7

SnapShots Added

I just installed a nice little tool on this site called Snap Shots that enhances links with visual previews of the destination site, interactive excerpts of Wikipedia articles, MySpace profiles, IMDb profiles and Amazon products, display inline videos, RSS, MP3s, photos, stock charts and more.

Sometimes Snap Shots bring you the information you need, without your having to leave the site, while other times it lets you "look ahead," before deciding if you want to follow a link or not.

Should you decide this is not for you, just click the Options icon in the upper right corner of the Snap Shot and opt-out.

Testing Live Writer

This is nothing more than a test to ensure I can use Windows Live Writer with my new blog.

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Setting Up Shop

The time has come to set-up a new blog. While MSDN has been a fun place to blog, I needed to feel a little more freedom (and some name-recognition). Stay tuned for what is (hopefully) to come.

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