When I heard that the Dynamic Language Runtime was going to be open source, and subsequently heard some things that Miguel said about it I knew it was only a matter of time before DLR support was added to Mono.  It sounds like only 15 days after the announcement of the DLR it's already made its way to Mono.  As M. David Peterson points out, it still has a ways to go but it's promosing to see them making such good progress so soon!

Mike Champion has a great post that offers up some theories for why LINQ to XML has been getting positive user reviews.  In short, he thinks it could be because Anders is "the man", and can read every developers mind.  He also has a magical crystal ball that he can look into to figure out what to include and more importantly what to exclude from the LINQ to XML API.  I might not be getting all the details of Mike's post right, so you *may* want to read what he said yourself rather than taking my word for it.

I've been working with LINQ to XML as part of my work on our LINQ book, and I must say it's a seriously kick ass XML API.  I've done a lot of XML work in the past and I've never had as much fun working with XML as I do when using LINQ to XML.  The key highlights for me are:

• Functional Construction: Have you ever created XML using existing .NET XML API's?  Enough said, functional construction beats the pants out of anything else out there for creating XML.
• Powerful Transformation capabilities: By combining the powerful querying capabilities of LINQ with the functional construction pattern for XML creation LINQ to XML provides a lot of really nice transformation capabilities.  In addition to supporting superb XML to XML transformations, we also get killer support for transforming our XML into object structures, LINQ to SQL objects, and whatever else you can think up.
• LINQ: What else needs to be said, sprinkling LINQ query support on top of an XML API makes for a kick ass query experience.  We get the best of XPath and XQuery but in a much nicer, cleaner, and straightforward API.

Now that I'm back on the "blogging wagon" I'll be looking to start the LINQ to XML for president campaign that I promised way back when.

Back in February I posted about when the right time for a new technology is.  As some likely guessed after seeing my review of Everyday Scripting with Ruby and the list of books that were on my next up list I decided to go with Rails as my new technology for one of the projects.  In a future post I'll detail how I've found the experience, and how it compares to .NET land but that's for another day.  Today, I'd like to point out the fact that nobody writes anything cool in .NET.  At least nobody writes any of the cool stuff that I need in .NET.  Ok, perhaps I'm exagerating a bit....in actuality the fact is that nobody writes social network visualization libraries in .NET. :)  The project that I'm working on that's using Rails involves social networks.  One of the things that I'll be getting to shortly is the actual visualization part of the project.  What I'd really love is if someone would write something as cool as this, in Silverlight.   That way I could have my Rails application call .NET code.  What could be better to piss off the Rails purists?  Afterall, I'm supposed to have given up all things .NET by now and truelly converted to Rails, right?  Ok, moving on....who wants to write prefuse in Silverlight?  It'd be a killer demo application to show off the capabilities of Silverlight and would undoubtedly make it so the only RIA platform anyone chooses is Silverlight.  Flash who?  Java FX what?  Flex...I think not.  With prefuse.NET, Silverlight is guaranteed instant mass approval.  Or maybe it'll just make me happy that I get to write .NET code that will access a RESTful Rails service for data that lives inside a rhtml page.  Either way you win, right?

In all seriousness I think Silverlight would be a great technology for building web based network visualization software.  While there's no way I'll have time to write something as fully functional as I'll need, I think I'll apply the learn a new technology even if it will take longer rule and give getting a basic network visualization demo in Silverlight working.  Luckily, I think some of the Silverlight samples (such as this one) might get me moving in the right direction.  If anyone cares to lend a hand, give me a shout!  Instance fame and fortune is within your grasp!

This week we have a story to add the ability to extract some of the data within our system into Excel format.  Upon initially hearing the requirement I thought of Visual Studio Tools for Office (VSTO), but after digging into the documentation for a bit, it doesn't seem that it was meant for our scenario.  VSTO seems to be ideal for Office Add-ins but quite lacking in its support for server based scenarios.

We did a bit of research and found a couple commercial options such as Software Artisans OfficeWriter and Aspose.Cells. Additionally, this evening Aaron emailed me about Carlos Aguiar's ExcelXmlWriter project that provides a free utility for generating Excel files as well as a nice generator. 

I'd certainly be interested in hearing about any other components that anyone has used for generating Excel in a server environment and/or any experiences with the products mentioned above.

My primary machine at home is a MacBook Pro.  Overall I really like it as my primary machine.  When I first got my MBP I used it almost exclusively to run Windows XP via BootCamp.  It wasn't until I tried using a beta of Parallels that promised BootCamp support that I ended up switching to Parallels and the wonder that is Coherence mode.  Over the last couple of months I've been doing mostly writing and/or work in TextMate so I've used XP via Parallels very little.  Lately I've had a couple of things come up that have me back in XP with VS.NET and some non book sample sized projects.  I'm finding it quite painful.  Most of my usual keyboard shortcuts don't work (althought I can get some to work by using the fn key), things seem painfully slow lately, and I'm not a happy camper.  I'm trying to figure out if I need to reconfigure my Parallels image, or if its time to switch back to BootCamp.

Today at work we had a brief discussion about whether using an IN or an EXISTS is more performant.  There were a couple different opinions, although most thought that EXISTS was faster.  It turns out that like most things in our wonderful software world there is not clear cut answer.  In general the below holds true:

• If the majority of the filtering criteria are in the subquery then the IN variation may be more performant.
• If the majority of the filtering criteria are in the top query then the EXISTS variation may be more performant.

Source: http://www.oracle-base.com/articles/misc/EfficientSQLStatements.php#Exists and this.

I assume the same holds true for SQL Server, although we're less interested in that at the moment.

A nice UI does wonders for an application.  As such if you're a Google Reader user, I recommend you checkout this Google Reader theme.

Mohammed Hossam El-Din has created an implementation of IQueryable that enables LINQ to be used against Flickr.  The LINQ to Flickr implementation leverages the Flickr.NET library.  I've been wanting to write my own implementation of IQueryable but it looks like everyone is beating me to all the good data sources. :)  Hopefully, once I finish my chapters for the LINQ book I'll have a chance to complete an implementation of IQueryable for an interesting data source...if there are any left  :)

Bart De Smart has a great series of posts on how to create a custom implemention of IQueryable that enables LINQ support for LDAP.

Over the last week or so I've been following a thread of blog posts that outline some of the issues that Twitter is experiencing.  For those of unfamiliar, Twitter is a "microblogging" site written in Ruby on Rails.  Over the last month or so they've seen some very serious growth.  They're supposedly seeing over 11,000 request/sec which is putting a hurting on their servers.  In this interview, Alex Payne points out some limitations in Rails, most notably it's lack of built in support for talking to multiple databases, that are making it particularly hard for them to handle the increased load.  As a result, several individual have put together plugins to make working with multiple read only slave databases possible.

• Magic Multi-Connections: A “facility in Rails to talk to more than one database at a time”
• ActsAsReadonlyable

Along with checking out the plugins mentioned above you may want to checkout the following posts that go into more detail on the problems.

• Twitter trouble
• Twitter, Ruby, and Scaling
• Rails and Scaling with Multiple Databases

What I find particularly interesting in the series of posts that talk about the scaling problems that Twitter is experiencing is that most of their problems are arising due to the database server getting nailed.  They've been able to scale out their web tier but that doesn't help their poor database server in the least.  I've been thinking about writing a series (or maybe just one) post on some of the things we've been thinking about regarding scaling our application.  It's not written in Rails, and it doesn't need to handle 11,000 req/sec but it does need to handle large sets of data and be "hot ass fast". We're currently positioned well to handle scaling out our services tier quite easily, but we need to do some more work to figure out how best to scale out our data tier.  We've had many discussions about how scaling out our services may not help since it will only increase the pressure on the database server.  Anyway, hopefully I'll get a chance to post more about the things that we're thinking about in a future post.

Jumping back to the Twitter/Rails scaling problems...I'll be interested to see how things end up with Twitter, and Rails.  I have a feeling that Rails will be better off when all is said and done, but will it be because of Twitter, or in spite of it?

Recently we've been discussing ways to increase the performance of some performance critical areas of our application.  As such, a number of individuals have been doing research into various options.  Through our investigation we came upon Oracle's Timesten In-Memory database.  I was familiar with many other In-Memory databases, such as Firebird (SQLite?, VistaDB?), but up until yesterday I wasn't aware that Oracle had a product in the in-memory space.  While Oracle doesn't currently offer a .NET native provider for Timesten, TankardSoft does offer a commercial native .NET data provider for Timesten that supports the recently released version 7 of Timesten. 

If you're an NHibernate user, and/or interesting in learning about how you can create custom implementations of LINQ using IQueryable, I strongly urge you to checkout what Ayende and Bobby Diaz (and others?) have been up to with LINQ to NHibernate.

Here are some of my favorite posts thus far:

• Implmenting Linq for NHibernate: A How to Guide Part 1
  
• Implementing Linq for NHibernate - Part 2 (Ordering and Paging)
• Implementing Linq for NHibernate - Part 3 (Aggregate and Element Operators)

My wife and I welcomed our son, Keegan James Eichert, into the world monday evening.  Needless to say posting will be slow for a while until we're all adjusted, as well as until I finish up the other projects that have been keeping me busy lately...such as the LINQ book. :)