Typed XML in SQL Server 2005 : Thoughts and digressions

Moving on

denisruc — Fri, 26 Oct 2007 07:52:00 GMT

I'm over 2 months late in writing this post. please forgive me for the delay, especially those of you who were nice enough to leave comments and questions and expected a response.

This is my last posting on my "Typed XML" blog. After almost 9 years at Microsoft I felt the need to do something else and on August 13th I joined the ranks of a well known online retailer. You'll still find some of my contributions in SQL Server 2008 when it is released. The entire team did a great job addressing some of the issues most often mentioned by customers. I don't want to steal anybody's thunder (or attract the attention of any lawyers :-) ) so I won't say much more but keep an eye out for that next version. I's going to rock!

Those 8 and 3/4 years at Microsoft were quite a ride. Thanks to everybody who helped make that time special.

Stardust memories

denisruc — Wed, 14 Mar 2007 04:04:00 GMT

The famous Stardust hotel and casino was torn down today. I was fond of the place since this was the hotel I stayed at when I first visited Vegas in the mid nineties. During our most recent trip to Nevada last summer my wife and I made sure we stopped by to bid farewell to the place. Its history was deeply linked to that of the town. Illustrious artists performed there. If you’ve seen the movie Casino, the story was in large part inspired by events involving the ownership of the Stardust. Yet, despite its past, the Stardust still had to go to make room for a new 4+ billion resort. By comparison, when the famous Parisian concert hall L’Olympia was threatened by developers, there was a public outcry to save it. Oh well … nothing is forever and I’ll always have those wonderful memories.

The latest issue of SQL Server Standard magazine is all about XML.

denisruc — Fri, 01 Sep 2006 20:42:00 GMT

The September issue of SQL Server Standard magazine is devoted to XML. I contributed an article where I look at ways to use XML to solve relational problems. Check it out!

Explaining the reasons behind some of XML datatype's limitations

denisruc — Thu, 29 Jun 2006 07:24:00 GMT

If you use XML in SQL Server 2005, and especially if you use it in association with schemas, I suggest you read Brandon's recent blog post about the limitations that were placed on the XML datatype. Brandon is one of our developers and he's got first-hand information about the design decisions that lie behind those limitations.

On a different note, I know my contributions to this blog have been few and far between recently. There's no shortage of topics I'd like to address, just a shortage of time.

If you leave me now…

denisruc — Wed, 21 Jun 2006 21:46:00 GMT

A man named Vincent Ferrari is making headlines today. He called AOL’s costumer service to cancel his account and ran into a less than cooperative representative. The twist is, Vincent was taping the call and posted the recording on his blog.

This article from MSNBC.com quotes AOL’s response to the story. As expected the representative is blamed for “[violating] customer service guidelines and practices” and he is “no longer with the Company”. Puh-lease!

Given that AOL is literally hemorrhaging customers these days, is it hard to believe that the company would have an aggressive customer retention policy? Since Vincent posted his story a lot of people have come forward to relate similar experiences. Are we to believe that they all ran into a few bad apples?

My wife used to be a long time AOL customer. Back 4 or 5 years ago, when we decided to cancel her account, the customer service reps also tried very hard to retain our business. I’ve heard similar stories from friends or coworkers dating back years. If AOL was aggressively trying to hold on to customers back when it was doing pretty well, is it hard to believe it would be even more aggressive today?

As always the little guy takes the blame though. I’m not saying the rep didn’t violate some policy or guideline, but his behavior didn’t come out of the blue. Aggressive policies from management breed aggressive behavior. You see it all the time (look no further than your local car dealerships). Maybe AOL needs to come to terms with the fact that dial-up is a dying business. I don’t believe it will disappear overnight, but it is a market which is bound to get a lot smaller than it currently is. AOL should be hard at work looking for replacement income streams rather than pressuring departing customers to stay with them for a little while longer.

Download SP1 today!

denisruc — Fri, 21 Apr 2006 04:23:00 GMT

Yesterday we released our first Service Pack for SQL Server 2005. You might remember a while back I had written a small post about being hard at work on SP1. Back then I avoided giving any details for fear of running afoul of corporate policy but since the bits are officially out, I can now talk about the changes that were made to the XML datatype functionality.

The very first thing we did was increase the number of schemas we can import by accepting some non-deterministic schemas. In short, non-deterministic content models are now acceptable, providing that the occurrence constraints are “0”,”1” or “unbounded”. For other values, we have to keep rejecting the schemas. The reason is that for “0”, “1” and “unbounded” we can build a basic automaton to handle validation of instances. When you use integer values strictly greater than one in your constraints, you get into cases where in order to validate properly you might sometimes have to backtrack and implementation becomes more complex. So far I haven’t seen a single industry schema that contains non-deterministic content models where occurrence constraints aren’t all “0”, “1” or “unbounded” (if you know of any please let me know)
With this improvement we’re now able to import the complete set of Office 2003 schemas into SQL Server 2005 (providing you remove all unique, key and keyref nodes and change all lax wildcards to skip but as we saw in this week’s other post, that’s not very hard to do).
The developer in charge of this change was Brandon and he contributes to the SQL Programmability & API Development Team Blog. If you were tired of seeing the “XML instances of the content model of type or model group '...' can be validated in multiple ways and are not supported.” error message and this fix changed your life he’s the man to thank.

Our second improvement has to do with query performance. Static typing makes things slower when querying typed XML vs. untyped XML. In particular, when dealing with very large schema collections and complex XPath expressions static typing was a big consumer of both memory and CPU cycles. Our static typing dev AdrianB came up with implementation changes that speed up the computation of XQuery static types a great deal.
For example, we had imported all the fpML schemas (available from http://www.fpml.org) into a schema collection and compiled the following query:
select convert(xml(fpML), '').query('//*:party')
On my office server this used to take 99.952 seconds with the RTM bits. With SP1 installed, it goes down to 0.328 seconds. That's over 300 times faster! As for memory consumption the number of pages is divided by almost 140. You shouldn’t expect such drastic improvements on all queries but if you use the descendant or descendant-or-self axis in your XPath expressions you're likely to notice the difference.
The code changes were significant and required something in the neighborhood of 175 new hand-crafted tests. Fortunately Adrian is a great guy to work with and in the end everything came together fine. He doesn’t have a blog yet but if you experience significant performance increases with your queries you should know he’s the one who made it happen.

I hope this post will make you want to try SP1 for yourself. Don’t hesitate to drop me a comment to share your experiences, good or bad.

-
Disclaimer:
This posting is provided “AS IS” with no warranties, and confers no rights.
Use of included script samples are subject to the terms specified at http://www.microsoft.com/info/cpyright.htm.

Working on SP1

denisruc — Sun, 04 Dec 2005 09:08:00 GMT

It's funny how I thought that with SQL Server 2005 out the door I'd have more time to spend on this blog and other long-delayed projects. Boy was I wrong! We kicked the SP1 work in high gear the minute we shipped SQL Server. I probably cannot reveal much at this point but if you're a user of the typed XML feature chances are you'll be pleased with this first service pack. We addressed issues with some pretty important scenarios. It'll be a few more months before we ship SP1 so you'll have to be patient but this will be worth the wait.

The long road to SQL Server 2005 ends here.

denisruc — Sat, 29 Oct 2005 00:02:00 GMT

This blog’s been very quiet this past couple of weeks, and for a very good reason; we were all hard at work putting the finishing touches to SQL Server 2005. We RTM’ed yesterday and if you’re an MSDN subscriber you can already download it (along with Visual Studio 2005).

I joined the SQL Server team almost 4 years ago so it’s been a very long journey for me personally and I’m happy to see the product ship. This is definitely the biggest product release I’ve ever been part of and I’m tremendously excited.

Please don’t hesitate to let me know what you think of the new XML feature. We’re already working hard on future improvements and we’ll welcome your feedback.

Branching

denisruc — Wed, 21 Sep 2005 20:02:00 GMT

When I started this blog 3 months ago my sole intent was to share knowledge pertaining to the XML data type in SQL Server 2005. I didn’t think I’d write about anything else. I didn’t even think there was anything else I wanted to write about. Well, it turns out I was wrong. When I blogged about Media Center PCs and the Katrina hurricane I got really interesting reactions and comments. Since I want this blog to remain solely a resource for XML users, I decided to start a new “personal” blog where I can muse about everything else, from current events and popular culture to technology and gadgets. Please join me at http://spaces.msn.com/members/freedomdude/.

Windows Media Center's popularity on the rise

denisruc — Thu, 08 Sep 2005 03:30:00 GMT

According to this report Media Centers are gaining in popularity. I bought one myself a week ago and I'm very happy with it. I was looking at purchasing a new desktop, mainly for work-related activities, and for my wife to edit her digital pictures. As I kept thinking about it I realized that I wanted a media center. A few of my colleagues have one and they rave about them quite a bit. Plus my TIVO can only store about 35 hrs worth of TV and there's constantly at least half of that taken up by Highway to Heaven episodes (I can't get enough of it... don't ask). I'm planning a 4 week trip for later this year and given all the shows I like to watch there's no way that a month worth of entertainment is going to fit.

My original plan was to have a local shop build me a customized rig when I stumbled upon a fancy HP Media Center with a 21" widescreen LCD monitor at some well known warehouse store. Resistance was futile... I bought it and ended up spending twice my original budget. First time ever that I buy a name-brand desktop. Anyway, it's working great. Last night I installed the Windows Media Center Extender on my XBox and for the first time in years I was able to watch shows from my home country on my television set. TV recording is the next step. If it's as easy to setup as the rest was, we'll be up and running in no time!

I've heard more than a few people complain about the lack of innovation in the PC space in the last few years. Maybe the reason why Windows Media Centers are so popular is because they open up such a brand new set of possibilities. If you're already living the "digital lifestyle" a Media Center is a must-buy.

Sad and grateful all at the same time

denisruc — Sat, 03 Sep 2005 05:24:00 GMT

I apologize in advance for a post that has nothing to do with SQL Server but I have this urge to express the sorrow and anger I’ve been feeling these past few days. Before you go any further please be mindful that the opinions expressed in this post are solely mine and may not be shared by my employer or my co-workers.

I am horrified that in the richest country in the world, after a forecasted natural disaster, people are being left to fend for themselves without food, water and sanitation. What struck me the most was the plight of the poor people gathered at the New Orleans Convention Center, desperately waiting for help that took days to arrive. Babies and senior citizens were dying of dehydration and I felt so helpless witnessing it all as if I were there and yet unable to help. Giving a little bit of money was all I could do. But money wasn’t what was needed most urgently. This country has the doctors, the food, the medication, and the vehicles that were required to rescue the victims and yet, none of it was where it was most needed.
In the end, I am certain that through the public’s generosity and the government’s efforts, there will be money to help the victims get their lives back to normal. But how many people will have died in New Orleans who didn’t have to?
Yesterday, I bought my 15 months old daughter her first pair of real shoes. I felt so grateful that I could do this… something as simple as going to the store and buying my baby a pair of shoes, when so many little ones in New Orleans have been wearing the same filthy diaper and going hungry for days.
In the end, this is a sobering reminder that I have been taking so many things for granted. Eventually I’m sure the raw emotion will subside and I’ll go back to complaining about inconsequential little things, like the price of a gallon of gas or the lack of decent cheese at my local supermarket. Still, I hope I won’t forget how I feel right now.

Back from TechReady

denisruc — Thu, 04 Aug 2005 05:22:00 GMT

I spent a good portion of my day at TechReady as a proctor for the hands-on labs. I met a few people who were going through the "XML Capabilities" tutorial. Unfortunately my duties in the lab prevented me from attending our PM's talk on XML. On the bright side I got a chance to run the "Service Broker" lab exercises. I must admit that until today I only knew the basics but now that I've actually played with this feature I'm really excited about it.

All in all it was a good day and a great opportunity to take a look at the bigger picture.

Improved error messages

denisruc — Wed, 27 Jul 2005 01:49:00 GMT

Somebody seems to like the fact that we recently added XPaths in validation error messages. I was pretty happy to read Bob's post since I lobbied for that feature, helped design it, and tested it. Prior to this all we gave the user was along the lines of "element 'b' found when element 'a' was expected", which might be adequate for very small instances but isn't very helpful when you're staring at a 10 Mb XML document.

Welcome

denisruc — Mon, 13 Jun 2005 18:27:00 GMT

Welcome to my newly created blog. My name is Denis Ruckebusch. I've been part of the test organization at Microsoft for the past 6 years. I spent the last 4 working on the new XML datatype feature in SQL Server 2005.

My main area of focus is typed XML. I mostly deal with XML schemas, validation of XML instances against thoses schemas, and running XQueries over typed XML. Since there are already a number of Microsoft bloggers dealing with the new XML functionality I will try to focus on issues specific to schemas and typed XML.

If you are currently using SQL Server 2005 and already have comments or questions about the use of typed XML, don't hesitate to drop me a line!