Monthly Archives: October 2006

Windows Forms to Windows Service Process to Process Communication Using WCF

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I've been working on a side project for an application that will run on Windows Vista.  It involves a Windows Service that does P2P and WCF Endpoint code to do some communication.  I wanted to setup a WinForms app that could talk to it.  I could just set up another http endpoint, but that would be slower and open up my security surface area.  Instead I wanted my application to talk to the Windows Service in memory.  The way to do this is through named pipes in WCF.  It was fairly easy to figure out how to do, but currently WCF is a bit picky on the details so it took a while to get it going.  I thought I'd share how to setup this up with some sample code.  Note: I didn't use WPF for the UI because I don't know it well enough yet and know Windowns Forms pretty well.  I imagine a WPF app would connect about the same.

Setting up the WCF Service and Contract

Setting up the Named Pipe

Setting up the Metadata Service

Connecting to the Service

 Enjoy!

ROW_NUMBER() OVER Not Fast Enough With Large Result Set

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So I'm working on improving the performance of the next version of Channel 9.  For those of you not familiar, our team created a new platform for our department to build community sites (blogs, forums, videos, tagging, etc).  You can see an example of the platform running on 10.  Currently, there's not a whole lot of data in the 10 database so we've been able to get away with murder from a performance standpoint.  Now that I've imported all the data from Community Server (Channel 9) to 10 (EvNet Platform), we've been finding that 250,000 rows doesn't perform very well with our current code.

The architecture of our platform is pretty simple.  There's an Entry table that houses Entries, Threads & Comments and the relationships between them.  When you're viewing a blog, you're looking at this table.  When you're looking at a forum, you're looking at this table.  We differentiate everything in our system by tags.  There's one for each forum, each blog, and content tags to describe what's in each entry.

Currently, to do paging we've been using the ROW_NUMBER OVER function.  It's a new feature of SQL Server 2005 and is very simple and easy to use.  Unfortunately, it doesn't work very well with a lot of rows (250,000 for example).  I did some searching and came across this gem of an article.  It uses an interesting trick to use SET ROWCOUNT to get the first record to start with in a paged result set, then you just run the query again and set the row count again to the number you want where the values are greater than the first row from the starting point of the paged result set and man is it snappy.  Do check it out if you're having troubles with performance of ROW_NUMBER() OVER.

Oh yah, I forgot to mention how much of an improvement this change made.  Before the change queries were taking about 8 seconds on average.  After the change, the queries now take less than 1 second.  Depending on if SQL has decided to cache the results or not, it's pretty much instantaneous.