Anders Lybeckers Weblog!

Memory Management in .Net

2012-01-02T12:34:34Z

I’ve written about Garbage Collection in the .Net Framework in version 2.0 and 3.0 a couple of years ago, but now Red Gate has created a simple and easy to understand funny comic “Memory Management in .Net”

Download the full one-page comic.

The .Net Framework 4.0 provides the new default behavior of background garbage collection.

An unfortunate travel story

2011-11-21T08:15:06Z

The last two and a half weeks have been interesting for me – Interesting in the “what doesn’t kill you makes you stronger” kind of way. Here is my challenging story…

I was on a leisure trip to Rome, Italy to see the sights. A beautiful city with many cites like the Vatican, the Colosseum and the Spanish Steps. I was supposed to flight directly to Manila, Philippines from Rome to assist a customer. The customer was finalizing my travel plans while I was in Rome. Unfortunately I lost my mobile phone in Rome which made it rather difficult to coordinate the travel plans, but after 3 or 4 different travel itineraries the flight was booked from Rome to Italy via Seoul, Korea.

I arrived in Manila through Seoul only to find out the hotel was not confirmed. To make things worse, they were fully booked and so were all the other hotels in the Makati area in Metro Manila. After an hours searching I managed to find a hotel room for the night, but I had to find another hotel for the next day.

Apparently available rooms where in short supply in Makati area as I had to change hotel the next five days. I could not book a consecutive reservation at the same hotel. I slept in rooms ranging from extravagant 150 m2 suites to 15 m2 crummy hotel room with ants in my bed. It was tiring, but the weekend retreat to lovely Philippine island of Bohol the following weekend made me see everything in a brighter light.

Friday I had to catch the flight to Bohol, so I took a taxi to the airport. Unfortunately the taxi was barely able to carry its own weight up the Skyway ramp and half way it gave up and broke down. I was now stuck in the middle of Manila with no other available taxi in sight and I was now late and might not make the flight to the lovely island of Bohol. I tried to persuade a tricycle to drive me to the airport, but they were not allowed to enter the airport area – then I tried to hire a Jeepney, but the driver was overly greedy and my attempt to barging failed. Luckily a taxi appeared from nowhere and I was on my way to the airport.

I arrived 25 minutes after the check-in was closed and 5 minutes before departure. I was immediately redirected to the supervisor, who luckily let me check-in – I rushed through the security check and directly onto the waiting flight.

It was a great weekend retreat to Bohol, where I say the Tarsier, Chocolate Hills and snorkeled at the coral reef where I saw clown fish and a turtle.

Back in Manila and an additional week work it was Friday and time to travel back home to Copenhagen, Denmark. Due to the confusion of the travel itineraries I apparently was supposed to travel home the day before, Thursday and not Friday. I was too late, as it was already Friday. So I had to find another flight from Manila to Copenhagen the same day… With some help from the very helpful Filipino Lee, I managed to get a flight Friday night with Thai Airways through Bangkok, Thailand.

It was a long trip home as Thai Airways does not have inflight entertainment systems in any of their aircrafts – I thought it was standard in this day and age.

I’m now home – still without a mobile phone. Fortunately I can already look back at this unfortunate trip a laugh. I enjoyed the trip both to Rome and the Philippines even though there where so many things working against me.

In-flight entertainment running on Windows

Using Lucene.Net with Microsoft Azure

2011-01-16T16:21:04Z

Lucene indexes are usually stored on the file system and preferably on the local file system. In Azure there are additional types of storage with different capabilities, each with distinct benefits and drawbacks. The options for storing Lucene indexes in Azure are:

Azure CloudDrive
Azure Blob Storage

Azure CloudDrive

CloudDrive is the obvious solutions, as it is comparable to on premise file systems with mountable virtual hard drives (VHDs). CloudDrive is however not the optimal choice, as CloudDrive impose notable limitations. The most significant limitation is; only one web role, worker role or VM role can mount the CloudDrive at a time with read/write access. It is possible to mount multiple read-only snapshots of a CloudDrive, but you have to manage creation of new snapshots yourself depending on acceptable staleness of the Lucene indexes.

Azure Blob Storage

The alternative Lucene index storage solution is Blob Storage. Luckily a Lucene directory (Lucene index storage) implementation for Azure Blob Storage exists in the Azure library for Lucene.Net. It is called AzureDirectory and allows any role to modify the index, but only one role at a time. Furthermore each Lucene segment (See Lucene Index Segments) is stored in separate blobs, therefore utilizing many blobs at the same time. This allows the implementation to cache each segment locally and retrieve the blob from Blob Storage only when new segments are created. Consequently compound file format should not be used and optimization of the Lucene index is discouraged.

Code sample

Getting Lucene.Net up and running is simple, and using it with Azure library for Lucene.Net requires only the Lucene directory to be changes as highlighted below in Lucene index and search example. Most of it is Azure specific configuration pluming.

Lucene.Net.Util.Version version = Lucene.Net.Util.Version.LUCENE_29;

CloudStorageAccount.SetConfigurationSettingPublisher(
    (configName, configSetter) =>
        configSetter(RoleEnvironment
        .GetConfigurationSettingValue(configName)));

var cloudAccount = CloudStorageAccount
    .FromConfigurationSetting("LuceneBlobStorage");

var cacheDirectory = new RAMDirectory();

var indexName = "MyLuceneIndex";
var azureDirectory =
    new AzureDirectory(cloudAccount, indexName, cacheDirectory);

var analyzer = new StandardAnalyzer(version);

// Add content to the index
var indexWriter = new IndexWriter(azureDirectory, analyzer,
    IndexWriter.MaxFieldLength.UNLIMITED);
indexWriter.SetUseCompoundFile(false);

foreach (var document in CreateDocuments())
{
    indexWriter.AddDocument(document);
}

indexWriter.Commit();
indexWriter.Close();

// Search for the content
var parser = new QueryParser(version, "text", analyzer);
Query q = parser.Parse("azure");

var searcher = new IndexSearcher(azureDirectory, true);

TopDocs hits = searcher.Search(q, null, 5, Sort.RELEVANCE);

foreach (ScoreDoc match in hits.scoreDocs)
{
    Document doc = searcher.Doc(match.doc);

    var id = doc.Get("id");
    var text = doc.Get("text");
}
searcher.Close();

Download the reference example which uses Azure SDK 1.3 and Lucene.Net 2.9 in a console application connecting either to Development Fabric or your Blob Storage account.

Lucene Index Segments (simplified)

Segments are the essential building block in Lucene. A Lucene index consists of one or more segments, each a standalone index. Segments are immutable and created when an IndexWriter flushes. Deletes or updates to an existing segment are therefore not removed stored in the original segment, but marked as deleted, and the new documents are stored in a new segment.

Optimizing an index reduces the number of segments, by creating a new segment with all the content and deleting the old ones.

Azure library for Lucene.Net facts

It is licensed under Ms-PL, so you do pretty much whatever you want to do with the code.
Based on Block Blobs (optimized for streaming) which is in tune with Lucene’s incremental indexing architecture (immutable segments) and the caching features of the AzureDirectory voids the need for random read/write of the Blob Storage.
Caches index segments locally in any Lucene directory (e.g. RAMDirectory) and by default in the volatile Local Storage.
Calling Optimize recreates the entire blob, because all Lucene segment combined into one segment. Consider not optimizing.
Do not use Lucene compound files, as index changes will recreate the entire blob. Also this stores the entire index in one blob (+metadata blobs).
Do use a VM role size (Small, Medium, Large or ExtraLarge) where the Local Resource size is larger than the Lucene index, as the Lucene segments are cached by default in Local Resource storage.

Azure CloudDrive facts

Only Fixed Size VHDs are supported.
Volatile Local Resources can be used to cache VHD content
Based on Page Blobs (optimized for random read/write).
Stores the entire VHS in one Page Blob and is therefore restricted to the Page Blob maximum limit of 1 TByte.
A role can mount up to 16 drives.
A CloudDrive can only be mounted to a single VM instance at a time for read/write access.
Snapshot CloudDrives are read-only and can be mounted as read-only drives by multiple different roles at the same time.

Additional Azure references

CNUG Lucene.Net presentation

2011-01-10T19:25:42Z

I have just held another presentation about Lucene.Net, this time in Copenhagen .Net user group. I hope everyone enjoyed the presentation and walked away with newfound knowledge how to implement full text search into their applications.

I love the presentations, like this one, where everyone participates in the discussion. It makes the experience so much enjoyable and everyone benefits of the collective knowledge sharing.

The presentation and code samples can be downloaded below:

Presentation (pdf | pptx)
Code samples (Visual Studio 2010)

I recommend the book “Lucene in Action” by Eric Hatcher. The samples in this book are all in Java, but they apply equally to Lucene.Net, as it is a 1:1 port of the Java implementation.

Microsoft Julekalender låge #7 vinder

2010-12-08T20:41:23Z

Yet another blog post in Danish, sorry.

Vinderen af gårsdagens Microsoft Julekalender låge #7 fundet. Vinderen er Gianluca Bosco, som har indsendt følgende WCF klient til servicen:

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Ready? Press [ENTER]...");
        Console.ReadLine();

        var factory = new ChannelFactory<Shared.IMyService>(
            new WSHttpBinding(),
            new EndpointAddress("http://localhost:8080/MyService"));

        factory.Endpoint.Binding.SendTimeout = new TimeSpan(0,2,0);

        var names = new[] { "Anders", "Bende", "Bo", "Egon",
            "Jakob", "Jesper", "Jonas", "Martin", "Ove",
            "Rasmus", "Thomas E", "Thomas" };

        var x = from name in names.AsParallel()
                    .WithDegreeOfParallelism(12)
                select Do(factory, name);

        x.ForAll(Console.WriteLine);

        Console.WriteLine("Done processing...");
        Console.ReadLine();
    }

    static string Do(ChannelFactory<Shared.IMyService> factory,
         string name)
    {
        var proxy = factory.CreateChannel();

        var result = proxy.LooongRunningMethod(name);

        return result;
    }
}

Gianluca har rigtig nok fundet den værste performance synder af dem alle, at man ikke skal instantier en ChannelFactory for hvert kald. Alene denne forbedring kan halvere tiden brugt ved et WCF kald.

Desuden fandt Gianluca den indbyggede fælde i min implementation. Server implementationen kalder Thread.Sleep (mellem 1 og 100 sekunder) for at simulere langvarigt arbejde. Default SendTimout på wsHttpBinding (og alle andre bindings) er 1 minut, hvilket betyder, at klienten vil få en TimeoutException pga. serverens lange arbejde.

Tillykke til Gianluca med hans nye helikopter.

Der er en mindre optimering, som kan forbedre performance yderligere og det er at kalde Open og Close på en Channel explicit. Det skyldes, at der i en implicit Open er thread synchronisation, således at kun én thread åbner en Channel og de resterende threads venter på at Channel er klar.

Hvis du har forslag til yderligere forbedringer, så skriv en kommentar.

Microsoft Julekalender låge #7

2010-12-07T06:45:28Z

Sorry – this post is in Danish.

Dagens opgave handler om Windows Communication Foundation. WCF er kompleks pga. mængden af funktionalitet og kan derfor virke indviklet. Kompleksiteten afspejles også i størrelsen på WCF assembly System.ServiceModel.dll, som er klart den største assembly i hele .Net Framework Class Library (FCL) … selv større end mscorlib.dll.

Opgaven:

Implementer en klient til nedstående service, som benytter WSHttpBinding med default settings.

[ServiceContract(Namespace = "www.lybecker.com/blog/wcfriddle")]
public interface IMyService
{
    [OperationContract(ProtectionLevel =
        ProtectionLevel.EncryptAndSign)]
    string LooongRunningMethod(string name);
}

public class MyService : IMyService
{
    public string LooongRunningMethod(string name)
    {
        Console.WriteLine("{0} entered.", name);

        // Simulate work by random sleeping
        var rnd = new Random(
            name.Select(Convert.ToInt32).Sum() +
            Environment.TickCount);
        var sleepSeconds = rnd.Next(0, 100);
        System.Threading.Thread.Sleep(sleepSeconds * 1000);

        var message = string.Format(
            "{0} slept for {1} seconds in session {2}.",
            name,
            sleepSeconds,
            OperationContext.Current.SessionId);
        Console.WriteLine(message);

        return message;
    }
}

Klienten må meget gerne være smukt struktureret og skal:

Implementeres i .Net 3.x eller .Net 4.0
Simulere et dusin forskellige klienter
Være så effektiv som mulig (tænk memory, CPU cycles, GC)

Beskriv kort jeres valg af optimeringer.

For at gøre opgaven nemmere at løse, så har jeg allerede løst den for jer… dog ikke optimalt. Download min implementation.

Send løsning til anders at lybecker.com inden midnat; vinderen vil bliver offentligt i morgen og vil blive den lykkelige ejer af en fjernstyrret helikopter med tilbehør, så den er klar til af flyve. En cool office gadget. Helikopteren er nem at flyve og kan holde til en del. Det ved jeg af erfaring

Se helikopteren flyve nedefor.

ANUG Solr/Lucene presentation

2010-10-27T22:56:42Z

I am on the train to Copenhagen after a successful presentation of Solr/Lucene at the Aarhus .NET user group.

The presentation went very well judging by the number of questions during the almost 2½ hour long presentation and the feedback afterwards. Love it – thanks

The presentation and code samples can be downloaded below:

Presentation (pdf|pptx)
Code samples (Visual Studio 2010)

Please do contact me if you have any further questions – I’ll love to help out.

WCF Timeouts

2010-10-14T10:22:58Z

The last two articles about WCF Throttling part 1 and part 2 would not be complete without looking at WCF timeouts. Any potentially lengthy operation must have a timeout or the system might end up waiting indefinitely – this is remarkably prevalent when working across any network connection (Yes, LAN connections too).

Timeouts are not directly related to throttling properties, but effect the way the service (or client) performance under load. Timeout properties can be perceived as an annoyance when sending larger messages or dealing with slow connections or services. The frustration increase as the naming of the properties can be deceiving. Read on… and I’ll explain

Below are the binding properties that all throw TimeoutExceptions if any of setting thresholds are exceeded:

OpenTimeout (TimeSpan) – the interval of time provided for an open operation to complete including security handshakes (WS-Trust, WS-Secure Conversation etc.). The default is 00:01:00.
CloseTimeout (TimeSpan) – the interval of time provided for a close operation to complete. The default is 00:01:00.
SendTimeout (TimeSpan) – the interval of time provided for an entire operation to complete. This includes both sending of message and receiving reply! The default is 00:01:00.
ReceiveTimeout (TimeSpan) – the interval of time that a connection can remain inactive, during which no application messages are received, before it is dropped. The default is 00:10:00.
- This setting is only used on the server-side and has no effect on client-side.
- When using Reliable Sessions remember to set the InactivityTimeout property on the reliableSession element to the same value as the ReceiveTimeout property, as both inactivity timers has to be satisfied.

Example of configuration file:

<system.serviceModel>
  <bindings>
    <netTcpBinding>
      <binding name="netTcpBindingConfig"
               openTimeout="00:01:00"
               closeTimeout="00:01:00"
               sendTimeout="00:01:00"
               receiveTimeout="00:10:00">
        <reliableSession enabled="true"
                         inactivityTimeout="00:10:00" />
      </binding>
    </netTcpBinding>
  </bindings>
</system.serviceModel>

WCF Throttling – Part 2

2010-10-11T18:05:40Z

In the WCF Throttling – Part 1 article the service throttling behavior was introduced.

There are other throttling features in WCF that are designed to protect the service from request flooding.

These WCF throttling feature are configured on the binding, service behaviors and endpoint behaviors.

Binding properties:

MaxConnections (int) – specifies the maximum number of outbound and inbound connections the service creates and accepts respectively. Default value is 10 connections. This setting only applies for statefull TCP connections like netTcpBinding and not stateless HTTP protocols like basicHttpBinding, wsHttpBinding or webHttpBinding.
MaxReceivedMessageSize (long) – the maximum size of a message (including headers), that can be received on a channel. The sender of a message exceeding this limit will receive a fault and the receiver will drop the message. The default value is 65,536 bytes (64K).

There are two additional properties on the binding that one might mistakenly think is request throttling properties. These are the MaxBufferPoolSize and MaxBufferSize properties and they control WCF memory Buffer Manager.

Note: remember to set the MaxReceivedMessageSize and MaxBufferSize properties to the same value if using TransferMode.Buffered or an ArgumentException will be thrown at runtime with the message “For TransferMode.Buffered, MaxReceivedMessageSize and MaxBufferSize must be the same value.”

Binding properties for the readerQuotas element – used by XmlReader under the hood:

MaxArrayLength (int) – the maximum allowed array length of data received from a client. The default is 16,384 (16K).
MaxBytesPerRead (int) – the maximum allowed bytes returned per read for the XmlReader. The default is 4,096 (4K).
MaxDepth (int) – the maximum XML nested node depth. The default is 32.
MaxNameTableCharCount (int) – the maximum characters allowed in a table name. This is the maximum length of an XML element or attributes identifier including XML namespace. The default is 16,384 (16K).
MaxStringContentLength (int) – the maximum characters allowed in XML element or attribute content. The default is 8,192 (8K).

The DataContractSerializer is by default used to serialize and deserialize messages as it is much faster the XMLSerializer, but with less features. The DataContractSerializer has a single property that can be configures at the endpoint or service behavior:

MaxItemsInObjectGraph (int) – maximum number of items in an object graph to serialize or deserialize. The default is 65,536 (64K).

Resist the temptation of settings any of these properties to Int.MaxValue and the likes, because determining the correct values are difficult. Throttle the service, so some clients gets served instead of risk boggling down the service with request flooding, resulting in no clients get served.

You will become the service hero in your organization by throttling instead of letting the service run wild

Example of configuration file:

<system.serviceModel>
  <behaviors>
    <endpointBehaviors>
      <behavior name="endpointBehavior">
        <dataContractSerializer maxItemsInObjectGraph="65536"/>
      </behavior>
    </endpointBehaviors>
    <serviceBehaviors>
      <behavior name="serviceBehaviors">
        <dataContractSerializer maxItemsInObjectGraph="65536"/>
      </behavior>
    </serviceBehaviors>
  </behaviors>
  <bindings>
    <netTcpBinding>
      <binding name="netTcpBindingConfig"
                maxReceivedMessageSize="65536"
                maxConnections="10">
        <readerQuotas maxArrayLength="16384"
                      maxBytesPerRead="4096"
                      maxDepth="32"
                      maxStringContentLength="8192"
                      maxNameTableCharCount="16384"/>
      </binding>
    </netTcpBinding>
  </bindings>
</system.serviceModel>

WCF Throttling – Part 1

2010-10-06T18:45:35Z

The default throttling settings in WCF has always been very conservative. There where configured conservatively to diminish the risk of request flooding. Without throttling settings a large number of requests will make the service unresponsive by consuming all resources trying to respond to all requests simultaneously.

Because of the very conservative settings many developers have run into what seems like WCF performance problems, but was actually incorrectly configured throttling settings.

WCF throttling is a service behavior configuration and each setting has effect dependent on the InstanceContextMode and ConcurrencyMode settings.

maxConcurrentCalls (int) – the maximum number of concurrent messages processing
maxConcurrentInstances (int) - the maximum number of concurrent InstanceContext (service type instances) objects processing
maxConcurrentSessions (int) - the maximum number of concurrent sessions processing

These throttling settings can be configured in code via the ServiceThrottlingBehavior in the System.ServiceModel.Description namespace or though configuration like below:

<system.serviceModel>
    <serviceBehaviors>
      <behavior name="throttlingServiceBehavior">
        <serviceThrottling maxConcurrentCalls="16"
                           maxConcurrentInstances="160"
                           maxConcurrentSessions="10"/>
      </behavior>
    </serviceBehaviors>
</system.serviceModel>

The default values in .Net 3.0/3.5 are:

maxConcurrentCalls = 16
maxConcurrentSessions = 10
maxConcurrentInstances = maxConcurrentCalls + maxConcurrentSessions

The default has changed in .Net 4.0 as the .Net 3.0/3.5 default values were too conservative and the increase in server resources – especially the number of cores available. The default values for .Net 4.0 are:

maxConcurrentCalls = 16 * Environment.ProcessorCount
maxConcurrentSessions = 100 * Environment.ProcessorCount
maxConcurrentInstances = maxConcurrentCalls + maxConcurrentSessions

The Environment.ProcessorCount property is misleading as the value is the number of cores (Hyper-Threading counts double). In my development laptop with four Hyper-Threading cores looks like this:

Raoul Illyés, Microsoft MVP

2010-10-05T19:52:38Z

A friend and former colleague of mine Raoul Illyés has been awarded Microsoft MVP for SQL Server.

I am delighted and lucky to continue working with Raoul and his new company Guide-line.

Congratulations – It’s about time

ASP.Net Security Vulnerability

2010-09-29T05:19:07Z

Friday the September 17th a serious security exploit was demonstrated at security conference by Juliano Rizzo and Thai Duong. A tool called POET (Padding Oracle Exploit Tool) was used to show the exploit in both .Net and Java.

POET exploits a well-known vulnerability in the way many websites encrypt text stored in ViewState, form authentication tickets, cookies, hidden HTML fields and request parameters.

It a deficiency in the encryption libraries in both Java and the .Net framework utilizing the fact that encrypted strings are padded in blocks of e.g. 8 bytes or 16 bytes or …. I will not go into details, as it is explained well in details here.

The exploit works on any block-cipher encryption mechanism, such as AES, DES and Triple DES.

The exploit is quite severe, as it can be used to download the web.config file.

The attack that was shown in the public relies on a feature in ASP.NET that allows files (typically javascript and css) to be downloaded, and which is secured with a key that is sent as part of the request. Unfortunately if you are able to forge a key you can use this feature to download the web.config file of an application (but not files outside of the application). We will obviously release a patch for this… Scott Gu

There are lots of systems affected, such as ASP.Net 1.0-4.0 (WebForms and MVC), SharePoint, Microsoft CRM, JavaServer Faces etc.

HTTPS with SSL/TLS does not protect your site.

Below is a video showing how to use the POET tool with DotNetNuke.

Scott Gu has workaround details until Microsoft releases a patch.

Update September 29th, 2010: A security update is released by Microsoft. More details about the patch on Scott Gu’s blog.

No related posts.

Configuring Windows 7 network priority

2010-09-10T19:01:59Z

Windows 7 apparently always prioritizes the wireless network connection (Wi-Fi) – no matter if a faster wired network connection is available. This is default behavior – go figure!

Luckily you can change it, but it isn’t easy to find. Do the following:

Go to “Network and Sharing Center” (e.g. through the “Control Panel”)
Click “Change Adapter Settings”
In the “Network Connections” window, press the ALT key on your keyboard to being up the menu bar.
Click the “Advanced” menu and then “Advanced Settings”
In the “Advanced Settings” windows on the “Adapters and Bindings” tab under “Connections”, you can change the network connection priority with the arrows on the right.

It will still connect to all available network connections (wireless and wired), unless they are disabled.

Enabling Danish for SQL Server FullText

2010-08-09T18:16:30Z

SQL Server FullText enables you to search large amount of strings fast, and it is easy to use. It hasn’t changed much since SQL Server 2000.
A simple getting started tutorial can be found on Code Project.

SQL Server FullText is easy to use in applications requiring string searching.

The Danish, Polish and Turkish wordbreaker and stemmer implementations for SQL Server FullText is not developed by Microsoft and therefore not enabled by default. The libraries are however part of the installation process and are therefore present on disk.

To make use of the Danish language capabilities in SQL Server 2008, register the libraries in registry and reload the FullText languages:

Download & run the DanishFulltext.reg file on the server. It will register wordbreaker, stemmer and default location of the thesaurus xml file.
Run the exec sp_fulltext_service ‘update_languages’ in a Management Studio.

Now verify that Danish is enabled with this query: SELECT name FROM sys.fulltext_languages

Note: The DanishFullText.reg assumes that SQL Server is a default instance (not a named instance). If not, modify the file by changing the MSSQL10.MSSQLSERVER to the instance name.

It is the same case with Polish and Turkish – they are not registered by default. See more in the MSDN article How to: Load Licensed Third-Party Word Breakers.

List of out of the box SQL Server 2008 FullText supported languages: Arabic, Bengali (India), Brazilian, British English, Bulgarian, Catalan, Chinese (Hong Kong SAR, PRC), Chinese (Macau SAR), Chinese (Singapore), Croatian, Danish, Dutch, English, French, German, Gujarati, Hebrew, Hindi, Icelandic, Indonesian ,Italian, Japanese, Kannada, Korean, Latvian, Lithuanian, Malay – Malaysia, Malayalam, Marathi, Neutral, Norwegian (Bokmål), Polish, Portuguese, Punjabi, Romanian, Russian, Serbian (Cyrillic), Serbian (Latin), Simplified Chinese, Slovak, Slovenian, Spanish, Swedish, Tamil, Telugu, Thai, Traditional Chinese, Turkish, Ukrainian, Urdu, Vietnamese.

Java 4-ever

2010-07-18T06:23:25Z

I find this video hilarious…

You should use the best tools at hand to solve the problem. That said; choosing between Java or .Net doesn’t really matter in most cases. There are however some areas where Java is a better choice and vice versa.

I can’t wait to see it in the cinema

PS. I do develop with Java even though I do not blog much about it.

Update: YouTube removed the video due to copyright claims. You can still see it JavaZone.

New blog – NoTech

Meeting the SQL Azure Development Team

2010-06-30T14:28:05Z

Last week I was at Microsoft HQ in Redmond, WA, USA. I was invited by the SQL Azure Development Team to look at some of the new unreleased features and comment on features in their roadmap.

Unfortunately most of the content was confidential, meaning that I was under NDA, so I may not disclose any details. Sorry :-/

During the week with the SQL Azure Development Team I was fortunate to be engaged in technical detailed discussion about some of the upcoming feature releases – mainly discussing the SQL Server features not currently available in SQL Azure. It was interesting and enlightening at the same time to discuss their technical challenges and why they have build SQL Azure the way they have.

All in all, my conclusion after this event is that Microsoft takes SQL Azure seriously and it will become a major player in the RDBMS world. It will not just be a SQL Server in the cloud, but a separate product with different market segments and different features. I am looking forward to a bright future with SQL Azure

Check for breaking changes in APIs

2010-08-09T18:11:24Z

Have you ever had the need to compare interfaces of two versions of the same framework?

If you have, then ApiChange is a tool for you. It’s open source, powerful and easy to use

I gave it a spin comparing current trunk version 2.9.2 of Lucene.Net with the latest official release version 2.4.0.

I downloaded ApiChange and ran the following command in a command prompt:

ApiChange.exe -Diff -old C:\Lucene.Net_2_4_0\Lucene.Net.dll -new C:\trunk\Lucene.Net.dll

The output lists all the differences, but here is a summary:

23 public types where removed
96 public types where added
158 public types where changed

Cool little tool with other features such as:

Diff public types for breaking changes.
Who uses a method?
Who uses a type?
Who uses implements an interface?
Who references me?
What format has the binary (32/64, Managed C++, Pure IL, Unmanaged)?
Search for all event subscribers and unsubscribers.

It’s based on Mono Cecil – a free IL parser, and not reflection as I initial thought. Go check it out…

Levels of reuse in Software Development

2010-06-01T06:52:33Z

One of the promises of object-orientation is reuse. Developing new software systems is expensive, and maintaining them is even more expensive. Reuse is therefore sensible in both business and technology perspectives.

With assistance of Erich Gamma, I have identified four levels of reuse.

First level of reuse: Copy/paste

Duplicating code or functionality makes it easy to reuse it. It’s a real timesaver at first, but keeping all the duplicates up-to-date and maintaining them is horrifying task. Not to mention the problems when forgetting to update one or more duplicates…

“Copy and paste programming is a pejorative term to describe highly repetitive computer programming code apparently produced by copy and paste operations. It is frequently symptomatic of a lack of programming competence, or an insufficiently expressive development environment, as subroutines or libraries would normally be used instead. In certain contexts it has legitimate value, if used with care.” Wikipedia

Second level of reuse: Class libraries

Reuse at class level or a set of classes in a software library is common and also fairly easy with object-oriented languages.

“Libraries contain code and data that provide services to independent programs. This allows the sharing and changing of code and data in a modular fashion. Some executables are both standalone programs and libraries, but most libraries are not executables …” Wikipedia

Third level of reuse: Design Patterns

Patterns allow you to reuse design ideas and concepts independent of concrete code.

“In software engineering, a design pattern is a general reusable solution to a commonly occurring problem in software design. A design pattern is not a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations. Object-oriented design patterns typically show relationships and interactions between classes or objects, without specifying the final application classes or objects that are involved.” Wikipedia

Fourth level of reuse: Frameworks

An object-oriented abstract design to solve a specific problem – often very specialized, like Unit Testing frameworks and Object-Relational Mapping frameworks, but can be large, complex or domain specific.

“A software framework … is an abstraction in which common code providing generic functionality can be selectively overridden or specialized by user code providing specific functionality. Frameworks are a special case of software libraries in that they are reusable abstractions of code wrapped in a well-defined API, yet they contain some key distinguishing features that separate them from normal libraries.” Wikipedia

It’s all about being pragmatic – not all software will reach fourth level of reuse and will be structured as frameworks – frankly it shouldn’t. That said; copy/past style development is unquestionably a wrong path.

What level is your company at?

Reuse in SQL Server 2008 Integration Services

Ageing pictogram

2010-08-09T18:12:11Z

I’m in Prague, Czech for the Apache Lucene EuroCon 2010; wandered around, where I saw this drawing on a house wall.

I find it hilarious – especially the natural shadow over the coffins. It’s just by pure coincidence that I was there, at the time of day where the doorway cast its shadow over the coffins

Finding Missing Indexes with SQL Server DMVs

2010-05-11T14:01:49Z

Finding Missing Indexes with DMVsSome time ago I wrote written about easy index wins for SQL Server 2005.

SQL server maintains statistics about indexes you should consider creating. This time I’ll show you a DMV (Dynamic Management View) that lists index candidates. This method works for SQL Server 2005 SP2 and later versions.

The query is based on three DMVs and returns index candidates where the calculated improvement is more than 10%:

SELECT
  migs.avg_total_user_cost * (migs.avg_user_impact / 100.0) * (migs.user_seeks + migs.user_scans) AS improvement_measure_pct,
  QUOTENAME(db_name(mid.database_id)) AS [database],
  QUOTENAME(OBJECT_SCHEMA_NAME(mid.object_id, mid.database_id)) AS [schema],
  QUOTENAME(OBJECT_NAME(mid.object_id, mid.database_id)) AS [table],
  'CREATE INDEX [missing_index_' + CONVERT(varchar(64), NEWID()) + ']'
  + ' ON ' + mid.statement
  + ' (' + ISNULL (mid.equality_columns, '')
  + CASE
      WHEN mid.equality_columns IS NOT NULL
	    AND mid.inequality_columns IS NOT NULL THEN ','
      ELSE ''
    END
  + ISNULL(mid.inequality_columns, '')
  + ')'
  + ISNULL(' INCLUDE (' + mid.included_columns + ')', '')
	  AS create_index_statement,
  migs.*,
  mid.database_id,
  mid.[object_id]
FROM sys.dm_db_missing_index_groups mig
  INNER JOIN sys.dm_db_missing_index_group_stats migs
	ON migs.group_handle = mig.index_group_handle
  INNER JOIN sys.dm_db_missing_index_details mid
	ON mig.index_handle = mid.index_handle
WHERE
	migs.avg_total_user_cost * (migs.avg_user_impact / 100.0) *
		(migs.user_seeks + migs.user_scans) > 10
ORDER BY
	migs.avg_total_user_cost * migs.avg_user_impact *
		(migs.user_seeks + migs.user_scans) DESC

It is important to note, that these are index candidates are only candidates and the improvements are based on estimates. The estimated improvement does not take extra disk space requirements and the maintenance of the indexes during updates, inserts and deletes. Furthermore it does not make recommendation about usage of clustered or non-clustered indexes.

This blog post is inspired by Bart Duncan’s Are you using SQL’s missing index DMVs?

Visual Studio 2010 keyboard shortcuts

2010-05-02T07:39:41Z

I am fond of keyboard shortcuts and wish I was a keyboard-shortcut-ninja and didn’t have to rely on the mouse all the time.

Using keyboard shortcuts boosts productivity and ergonomically a better choice, as the risk of getting a tennis elbow/mouse elbow diminish.

Source of keyboard shortcuts for Visual Studio 2010:

Removing SVN folders with PowerShell

2010-04-24T14:42:57Z

I need to remove.svn folders from an existing Visual Studio Solution a customer email me, so I could commit it to another SVN repository.

If I had access to the original SVN repository, I could have used the export function, as it does not include the .svn folders – but no, it should not be that easy.

What the heck, I have been putting it off way too long to start working with PowerShell. It should be a familiar environment as it is object-oriented with a C# like syntax with full access to the .Net Framework Base Class Libraries (BCL).

Here it goes – my first PowerShell script…

function RemoveSvnFolders([string]$path)
{
    Write-Host "Removing .svn folders in path $path recursive"

	Get-ChildItem $path -Include ".svn" -Force -Recurse |
		Where {$_.psIsContainer -eq $true} |
		Foreach ($_)
		{
			Remove-Item $_.Fullname -Force -Recurse
		}
}

The Write-Host Cmdlet just writes the content to console window.

If you are like me, a PowerShell novice – start with the Getting Started with Windows PowerShell article and use the free tool PowerGUI from Quest Software. It’s PowerShell IDE with an integrated syntax highlighter editor and debugger.

In line 5 the Get-ChildItem Cmdlet iterates the path recursively and filtering the result to include only “.svn” files and folders. The force parameter allows the cmdlet to get items that cannot otherwise be accessed by the user, such as hidden or system files. Get-ChildItem Cmdlet can also iterate the registry.

Afterwards the result from Get-ChildItem Cmdlet is piped to the Where-Object Cmdlet (Where is an alias for Where-Object). The psIsContainer is a property on a folder. If it is equal to true pass it to the next pipe. I could have written the following instead:

Where {$_.mode -match "d"}

Use the below statement to list all properties for the files and folders in the current folder:

Get-ChildItem | format-list -property *

The foreach statement iterates every item and deletes the folder with the Remove-Item Cmdlet.

Calling the method is as simple as:

RemoveSvnFolders("c:\svn\My Solution")

On TechNet there is a myriad of articles with the root Windows PowerShell Core and more task oriented like A Task-Based Guide to Windows PowerShell Cmdlets and Piping and the Pipeline in Windows PowerShell.

Remove SVN folders PowerShell Script.

Happy PowerShelling…

No related posts.

Miracle Open World 2010 Lucene Presentation

2010-08-09T18:12:40Z

The conference is over and it was a great success. I meet a lot of new people and had lots of technical discussions about .Net, graph databases, freetext search, SQL Server, Oracle Service Bus, debugging with WinDbg and extensions.

The slides and demo code for my Lucene session is available here:

My session “Making freetext search with Lucene.Net work for you” abstract:

Lucene is an open source full-featured text search engine library, making searching in large amounts of text lightning fast. Lucene are in use by many large sites like Wikipedia, LinkedIn, MySpace etc.

It is easy to get started with Lucene, but there are many pitfalls… In this session you will learn about the do’s and don’t’s for indexing and searching, tools, scaling, new features in version 2.9 and some of the more advanced features.

This presentation will use the Microsoft .Net implementation of Lucene named Lucene.Net, but the content of this presentation applies for ported versions of Lucene.

Speaking about Lucene at Miracle Open World 2010

2010-04-04T17:04:10Z

The conference Miracle Open World 2010 is soon upon us at Legoland (April 14.-16.)

There will be four tracks this year: Oracle track, SQL Server track, .Net track and a workshop track.

The conference is legendary because time spend at the conference is divided between 80% technical stuff and 80% social networking. No kidding’ socializing is a big part of this conference with gala-dinner and the not-to-miss beach party at Lalandia Aquadome (including drinks).

This year I only have one session where I’ll be presenting Lucene.Net.

Session abstract:

Lucene is an open source full-featured text search engine library, making searching in large amounts of text lightning fast. Lucene are in use by many large sites like Wikipedia, LinkedIn, MySpace etc.

It is easy to get started with Lucene, but there are many pitfalls… In this session you will learn about the do’s and don’t's for indexing and searching, tools, scaling, new features in version 2.9 and some of the more advanced features.

This presentation will use the Microsoft .Net implementation of Lucene named Lucene.Net, but the content of this presentation applies for ported versions of Lucene.

At the time of writing, 207 participants have registered for the conference. You can still register – it’s not too late.

See more at the Miracle Open World 2010 site.

Upgraded the wireless network at work

2010-04-04T14:47:19Z

With new Wireless Access Points spread around the office building, we can now utilize the full potential of the 802.11n protocol.

It’s my birthday today

2010-04-02T07:07:17Z

Yep – It’s true, I’m one year older today.

The American singer and songwriter Marvin Gaye and Hans Christian Andersen – the world famous Danish author and poet noted for his children’s fairy tale stories like “The Ugly Duckling” and “The Little Mermaid” – both where born April 2^nd.

This is also the day, The Falklands War started where Argentina invades the British Falkland Islands in 1982.

You can read more about April 2^nd on Wikipedia.

Now I’m already 33 years old :-S

New blog – NoTech

Compress files into individual archives

2010-03-21T13:20:29Z

I needed to compress a lot of files into individual zip archives – I did not want to do it manually

Add the following to a bat file and every file with the extension txt will be compressed into a Zip archive with 7-Zip file archiver:

@echo off
For %%f in (*.txt) do 7z.exe a -tzip %%f.zip %%f

E.g. a.txt will be compressed to the archive a.txt.zip

This was not exactly what I needed, as the dual extension caused problems in later processing. In needed to remove the extension preceding the zip extension – therefore:

@echo off
For %%f in (*.txt) do 7z.exe a -tzip %%~nf.zip %%f

E.g. a.txt will be compressed to the archive a.zip

That’s it

No related posts.

SQL Server build version

2010-10-04T05:09:18Z

Working with SQL Server it is often important to know which edition, version and service pack applied to the instance.

This information easily retrieve with either of these two system functions ServerProperty or @@Version:

SELECT @@VERSION

SELECT SERVERPROPERTY('ProductVersion'),
       SERVERPROPERTY('ProductLevel'),
       SERVERPROPERTY('Edition')

Both of the returns roughly the same information, but I tend to use the @@Version function as it easier to remember and type.

With the ServerProperty function additional information can be retrieved like MachineName, InstanceName or BuildClrVersion. See more about the ServerProperty function on MSDN.

From the build number alone it is possible to figure out which version of the SQL Server and Service Packs applied via the below table:

	RTM	SP1	SP2	SP3	SP4
SQL Server 2008 R2	10.50.1600.1
SQL Server 2008	10.00.1600.22	10.00.2531	10.00.4000
SQL Server 2005	9.00.1399.06	9.00.2047	9.00.3042	9.00.4035
SQL Server 2000	8.00.194	8.00.384	8.00.532	8.00.760	8.00.2039

Credit for the above table is due to this site.

Update April 30th 2010: Added SQL Server 2008 R2 RTM build number

Update October 4th 2010: Added SQL Server 2008 SP2 build number

Transferring SQL Server logins

2010-03-01T17:31:53Z

I had to migrate a SQL Server 2008 instance on to new hardware.

I choose to detach the databases and attach the databases on the new SQL Server 2008 instance on the new hardware. This was easy, but the origin SQL Server instance used mixed SQL Server and Windows Authentication Mode. This also meant that I had to migrate SQL Server logins, as the logins where a mix of SQL Server logins and Active Directory domain accounts/groups.

Both the SQL Server logins and domain accounts/groups has an unique SID (Security Identifier), which ties the logins in the SQL Server with the users in the database.

While the domain accounts/groups resides in the Active Directory domain controllers, the SQL Server logins only resides in the SQL Server. This means, moving domain accounts/groups is easy, by just creating the same users in the new SQL Server instance, but SQL Server logins is not. I could either choose to:

Recreate the SQL Server logins with new users in each of the databases, as new SQL Server logins will get new SIDs and therefore not be tied to the old database users. This also requires that you know all the passwords – alternative reconfigure all the client applications using SQL Server logins
Transfer the SQL Server logins with SID and password

How to transfer SQL Server logins? See the KB article: How to transfer the logins and the passwords between instances of SQL Server 2005 and SQL Server 2008. Easy

Cisco VPN (IPSec) support on 64 bit platforms

2010-05-31T18:08:34Z

I like Windows 7 x64, but I hate Cisco’s lack of support for the IPSec protocol on 64-bit platforms. Many of our customers use IPSec and the Cisco VPN Client – therefore I cannot connect to the customer’s network via IPSec VPN tunnels on my primary laptop

Until today

A colleague of mine recommended Shrew Soft VPN Client. It’s free and works like a charm. It’s a lot faster connecting and negotiating to the remote network than Cisco VPN Client, so fast in fact, that I initially thought that the connection failed. I’ve been using it for a couple of days, connecting to multiple customers, without any issues.

Why does Cisco implement a VPN client for x64 platforms?

I guess it is a money making scheme. They want to push their new Cisco VPN boxes and their new Cisco AnyConnect VPN client (expensive!), which makes use of SSL VPN.

Greg Ferro has another critical article Early Death of Cisco VPN Client Forces VPN License Fees with more details about Cisco’s SSL VPN.

I know of a commercial IPSec VPN client from NCP that works fine with Cisco IPSec VPN tunnels, but the steep price tag of $144 USD + taxes is too much.

Update May 31, 2010: Cisco has released an x64 version of their client tools for Windows 7 with IPSec protocol support. Either my money making scheme hypotheses is wrong or Cisco feared the wrath of my blog readers

No related posts.

Lucene.Net and Transactions

2010-08-09T18:13:13Z

Lucene.Net is an open source full text search engine library (a port from Java). It is stable and works like a charm – I’ve been using Lucene.Net for a couple of years now and implement a handful of solutions. Lucene is awesome.

If you want to try working with Lucene.Net, then the DimeCast.Net crew has recently made two short webcasts introducing Lucene.Net.

.Net 2.0 made it simple to use transactions with the System.Transactions namespace. Two of the great features are automatic elevation to distributed transactions (and utilize the Distributed Transaction Coordinator) and the other is the simplicity of creating your own transactional resource managers.

The .Net Framework defines a resource manager as a resource that can automatically enlist in a transaction managed by System.Transactions – which means that any object that implements any of the following interfaces can enlist in a transaction:

IEnlistmentNotification for the two-phase-commit protocol
IPromotableSinglePhaseNotification for the single-phase-commit protocol (non-distributed transactions)

To implement a resource manager for the Lucene.Net IndexWriter, and therefore make it transactional, all you have to do is the following:

public class TransactionalIndexWriter : IndexWriter, IEnlistmentNotification
{
    #region ctor
    public TransactionalIndexWriter(Directory d, Analyzer a, bool create, MaxFieldLength mfl)
        : base(d, a, create, mfl)
    {
        EnlistTransaction();
    }
    /* More constructors */
    #endregion

    public void EnlistTransaction()
    {
        // Enlist in transaction if ambient transaction exists
        Transaction tx = Transaction.Current;
        if (tx != null)
            tx.EnlistVolatile(this, EnlistmentOptions.None);
    }

    #region IEnlistmentNotification Members
    public void Commit(Enlistment enlistment)
    {
        base.Commit();
        enlistment.Done();
    }

    public void InDoubt(Enlistment enlistment)
    {
        // Do nothing.
        enlistment.Done();
    }

    public void Prepare(PreparingEnlistment preparingEnlistment)
    {
        base.PrepareCommit();
        preparingEnlistment.Prepared();
    }

    public void Rollback(Enlistment enlistment)
    {
        base.Rollback();
        enlistment.Done();
    }
    #endregion
}

You can use it like so:

IndexWriter indexWriter = null;
TransactionScope tx = null;

try
{
    tx = new TransactionScope();
    indexWriter = new TransactionalIndexWriter(...);

    // Perform transactional work
    indexWriter.AddDocument(new Document());
    indexWriter.AddDocument(new Document());
    indexWriter.AddDocument(new Document());

    // Connect to Database, MSMQ etc. to elevate to a distributed transaction

    // Commit transaction
    tx.Complete();
}
finally
{
    if (tx != null)
        tx.Dispose();

    if (indexWriter != null)
        indexWriter.Close();
}

Fairly simply uh? Just remember to instantiate the TransactionalIndexWriter or call the public method EnlistTransaction within the scope of an ambient transaction.
You might consider implementing IDisposable for TransactionalIndexWriter so you can take advantage of the using statement.

I will leave it to the reader to implement a TransactionalIndexReader.

If you want to try working with Lucene.Net, then the DimeCast.Net crew has recently made two 10 short webcast introducing Lucene.Net (http://dimecasts.net/Casts/ByTag/Lucene).

TechEd Berlin 2009

2009-11-06T20:21:47Z

I’m going to TechEd conference in Berlin next week. Are you going?

I haven’t taken the time to browse through the session catalogs yet, but I will be seeking information about:

Microsoft’s acquisition of FAST Search and how Microsoft incorporates into their products
Microsoft SQL Server 2008 R2 and especially the spatial support for Reporting Services
The new features of Windows Communication Foundation 4.0, the redesigned Windows Workflow Foundation 4.0 and .Net 4.0 in general.
The Windows Azure Platform
ASP.Net MVC 2

If you are going, drop me a mail and I’ll buy you a beer. That’s the least I can do for my readers

ASP.NET MVC Best Practices

2009-10-29T19:06:22Z

I love ASP.Net MVC – It has made web development fun. It also introduced new pitfalls…

Microsoft MVP Simone Chiaretta has fathered 12 ASP.NET MVC Best Practices worth reading.

In particular I find the these items interesting:

“DomainModel != ViewModel” with the ASP.NET MVC View Model Patterns
“Pay attention to the Verbs” with the PRG Pattern (Post-Redirect-Get)

New blog – NoTech

Initial slow WCF request

2009-10-23T21:01:06Z

If working with any of the HTTP Bindings you might experience that the first WCF request takes a long time to complete.

This is because the initial HTTP connection tries to get the proxy settings automatically. This is done by requesting the configuration via a HTTP GET http://wpad/wpad.dat. If proxy server automatic configuration is not configured, the request times out and the initial WCF can send the request directly to the destination address. This may add 30 seconds to the initial WCF request!

You can disable this behavior by specifying UseDefaultWebProxy = false on the binding.

You can read more about Web Proxy Auto-Discovery Protocol ( WPAD ) at Wikipedia.

This applies to basicHttpBinding, wsHttpBinding, wsDualHttpBinding, webHttpBinding, ws2007FederationHttpBinding, wsFederationHttpBinding, basicHttpContextBinding, wsHttpContextBinding and the new Azure ServiceBus bindings basicHttpRelayBinding, wsHttpRelayBinding, webHttpRelayBinding

No related posts.

Reuse in SQL Server 2008 Integration Services

2009-10-22T19:27:34Z

Or lack of

My current project requires SSIS (SQL Server 2008 Integration Services) packages for ETL processing.

SSIS seems very capable, but lacks fundamental things that a developer like me takes for granted. I did not expect SSIS to have the ability of inheritance as it isn’t object-oriented, but I did expect functions or methods like a procedural language or set-based languages like T-SQL. Sadly the answer is no.

You can make script tasks or script component with custom T-SQL or .Net code, but logic in expressions you have to duplicate.

I goggled reuse and SSIS and found this statement in an article about reuse in SSIS at SqlServerCentral.com:

Let’s not forget, copy&paste is the first level of code reuse

In essence it’s true, but I would hope the entire Information Technology industry has move way beyond this point years ago.

This post at the Microsoft SQL Server forum confirms this horrific truth about lack of reuse in SSIS

Monitors and thread context

2009-10-15T19:27:54Z

Running the below code will fail – why?


var syncRoot = new object();

Monitor.Enter(syncRoot);

ThreadPool.QueueUserWorkItem(x => Monitor.Exit(syncRoot));

It will throw a SynchronizationLockException with the message “Object synchronization method was called from an unsynchronized block of code.”

It is because System.Threading.Monitor requires the Enter and Exit methods must be executed on the same thread for the same synchronization object.

I did not know that :-/

New blog – NoTech

New blog – NoTech

2009-10-14T06:24:34Z

A talented colleague of mine Thomas Schou-Moldt has started blogging about software development processes and methods. He is passionate about the subject and writes well.

The blog is in Danish and called NoTech.

Blog description:

Here I’ll share my opinions, joys and frustrations about software development and IT projects – both the good stories and horrendous experiences.

No related posts.

Amazon Virtual Private Cloud

2009-08-26T20:16:12Z

If you are interested in cloud computing, but you never known how to adopt this new paradigm in your shop due to ignorance I encourage you to look at the Amazon EC2 and related services.

One of the things that have kept me and properly many others from migrating our applications and services to the cloud has been due to the nature of most software requiring integration to legacy systems behind a company firewall.

Amazon’s new service – Amazon Virtual Private Cloud enables you to extend the company’s network to Amazon’s cloud via a secure VPN connection.

Read more about this new service from Amazon on Werner Vogels’ article Seamlessly Extending the Data Center – Introducing Amazon Virtual Private Cloud.

New blog – NoTech

Change Data Capture (CDC) in SQL Server 2008

2009-08-11T13:38:53Z

I where planning to write a blog post about Change Data Capture (CDC) in SQL Server 2008, but then I stumbled upon Pinal Dave’s article Introduction to Change Data Capture (CDC) in SQL Server 2008.

It is a thorough overview of Change Data Capture (CDC).

MSDN reference for Change Data Capture (CDC).

40+ Essential Front End Web Developer Cheat Sheets

2009-06-23T06:32:21Z

tripwiremagazine.com has gathered a neat collection of cheat sheets for web developers.

I’m not a front end web developer, so I’m in desperate need of tools and cheat sheets that can help me look good, when venturing into the world of web design

Free SQL Server tools

Visual Studio 2010 Beta 1 available

2009-07-13T18:57:25Z

I can’t wait to see what Microsoft can get out of WPF with the new WPF-based IDE.

The Microsoft developer and platform evangelist Dan Fernandez has written an installation cheat sheet guide.

Update 13th July 2009: On the BCL Team Blog Justin Van Patten has written the blog post What’s New in the BCL in .NET 4 Beta 1.

How to view default values for a WCF binding

2010-08-29T06:25:38Z

… or create a custom binding from a build-in binding.
… or create an administrative XML-based configuration from an administrative programmatic configuration.

Below codes does all that:

// Specify the source binding
// - Programmatic binding
// - Administrative XML-based binding
// - Convert to custom binding

/* Programmatic binding */
var binding = new BasicHttpBinding();
binding.TransferMode = TransferMode.Streamed;
binding.MaxReceivedMessageSize = 10000;

/* Administrative XML-based binding */
// var binding = new BasicHttpBinding("basicHttp");

/* Convert to custom binding */
// var wsBinding = new WSHttpBinding("wsHttp");
// var binding = new CustomBinding(wsBinding);

string outputConfigFile = "out.config";

Configuration machineConfig = ConfigurationManager.OpenMachineConfiguration();

var fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = outputConfigFile;
fileMap.MachineConfigFilename = machineConfig.FilePath;

Configuration config = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
config.NamespaceDeclared = true;

var scg = new ServiceContractGenerator(config);

string sectionName, configName;
scg.GenerateBinding(binding, out sectionName, out configName);
config.Save();

The programmatic source binding will create a configuration file with all default values for the BasicHttpBinding except for TransferMode and MaxReceivedMessageSize attributes like so:

<basichttpbinding>
    <binding name="BasicHttpBinding"
             closeTimeout="00:01:00"
             openTimeout="00:01:00"
             receiveTimeout="00:10:00"
             sendTimeout="00:01:00"
             allowCookies="false"
             bypassProxyOnLocal="false"
             hostNameComparisonMode="StrongWildcard"
             maxBufferSize="65536"
             maxBufferPoolSize="524288"
             maxReceivedMessageSize="10000"
             messageEncoding="Text"
             textEncoding="utf-8"
             transferMode="Streamed"
             useDefaultWebProxy="true">
        <readerquotas maxDepth="32"
                      maxStringContentLength="8192"
                      maxArrayLength="16384"
                      maxBytesPerRead="4096"
                      maxNameTableCharCount="16384" />
        <security mode="None">
            <transport clientCredentialType="None"
                       proxyCredentialType="None"
                       realm="" />
            <message clientCredentialType="UserName"
                     algorithmSuite="Default" />
        </security>
    </binding>
</basichttpbinding>

I found this tip by Brian McNamara on the MSDN WCF forum.

World’s first electronic annual general meeting

2009-04-16T12:02:16Z

Today I just witness the electronic annual general meeting for the investment company SparIndex. This is the first 100% electronic annual general meeting ever.

The stakes was high, especially for the system owner VP Securities as journalists and photographs wandered around the offices ready to report success or failure in the media.

My job as a technical consultant, together with a handful of other techies, was to monitor the solution during the live annual general meeting. Our job was to prevent any technical glitches or in the event of a crash recover as fast as possible.

The tension was high right up to the last minute before the premiere, but everything went smooth.

Screenshot of the World’s first electronic annual general meeting

Loooong running sql statement

2009-04-06T10:39:29Z

I was using SQL Server Profiler on a SQL Server 2005 Enterprise Edition looking for performance culprits, when I stumbled upon this very long running process.

I think this must be a world record.

This statement has only used 16 milliseconds of CPU but it has been running for more than 500.000 years!

In-flight entertainment running on Windows

2009-03-24T10:33:13Z

Recently when I was flying back to Europe from South Africa with Lufthansa on Airbus A340-600 the In-flight entertainment crashed just before takeoff. They had to restart the entire system. I could see the entire reload of the system including the initial download with 115K baud XModem protocol download.

Yikes! I hope that only non-vital systems are running Windows for an airliner.

New blog – NoTech

Scary SQL Server 2005 & 2008 bug

2009-03-28T14:27:28Z

Watch out when using @@IDENTITY and SCOPE_IDENTITY() in your applications. Below is a quote from a Microsoft SQL Server engineer.

… whenever a parallel query plan is generated @@IDENTITY and SCOPE_IDENTITY() are not being updated consistently and can’t be relied upon.

You can find more about the bug and workarounds at the SQL Server bug report.

UPDATE 28MAR2009: Pinal Dave has a more detailed blog post about the bug with workaround.

ASP.Net MVC 1.0 released

2009-03-18T21:02:12Z

I have been playing around with the ASP.NET MVC for a couple of month and cannot wait to start the first commercial project – hopefully next week

Frameworks like the ASP.NET MVC, MVCContrib and jQuery has sparked a renewed interest in web development, which has been dormant for years.

New blog – NoTech

How to check for and enable read committed snapshot isolation

2011-02-10T01:45:31Z

Run the below query to see which databases that uses read committed snapshot isolation:

SELECT name, is_read_committed_snapshot_on FROM sys.databases

To enable it on a specific database run the below query:

ALTER DATABASE [<databasename>]
SET READ_COMMITTED_SNAPSHOT ON

As a developer I am in love with read committed snapshot isolation feature for SQL Server 2005+. Transactions can read and write simultaneously the same piece of data – no read/write contention due to row versioning. Writers will block other writers though.

Normal conflicting scenarios:

Simultaneously write and read of the same data.

Read committed isolation: The reader will wait for the writer to release the exclusive lock.
Read committed snapshot isolation: The reader will not block, but receive the latest committed data (latest row version).

Simultaneously writes of the same data.

Read committed isolation: The second writer will wait until the first transaction completes because of an exclusive lock.
Read committed snapshot isolation: Same as read committed isolation.

Read more about read committed snapshot isolation and isolation levels in the Isolation Levels in SQL Server 2005 article.

Update 02FEB2011: Amended the article due to Tom’s comments.

Disable and enable all database constraints

Handcrafting the WCF client

2009-03-08T15:58:47Z

Two years ago I wrote an article Building a Windows Communication Foundation client, describing three ways of creating WCF clients. I did not mention the fourth one, as I did not know at the time. Now I am older and wiser

The four ways of creating a WCF client are:

Visual Studio’s “Add Service” reference
Service Model Metadata Utility Tool (SvcUtil.exe) command line tool
Dynamic proxy with ChannelFactory
Handcrafting the WCF client

The last two options are only viable for WCF to WCF implementations where you either have control of both service and client or the service provider supplies a .Net assembly. Because both of them require the service contract aka the .Net interface marked with ServiceContractAttribute and OperationContractAttribute.

Anybody that has tried the “Add Service” reference in Visual Studio knows it is broken. First of all it generates an enormous amount of files, even for the simplest service contract.

Secondly it sometimes corrupts the state of the generated files, so you have to remove the reference and then add it again.. Just try to google it and you will find many frustrated developers. Do not use it!

The SvcUtil.exe is better and has a vast number of options. This is the preferred option for non .Net services or where the service contract interface is not available.

The dynamic proxy with ChannelFactory is useful, but be aware that the interface returned does not implement IDisposable, but the implementation does. See below:

var factory = new ChannelFactory<ihelloworldservice>("myEndPoint");

IHelloWorldService proxy = factory.CreateChannel();

using (proxy as IDisposable)
{
   MessageBox.Show(proxy.HelloWorld());
}

Finally the handcrafted version – the one I want to talk about. Writing the WCF client by hand is fairly easy – it requires the implementation to inherit from ClienBase and implementing the service contract interface. Below is first a simple service contract IHelloWorldService:

[ServiceContract(Namespace = "www.lybecker.com/blog/HelloWorldService")]
public interface IHelloWorldService
{
   [OperationContract]
   string HelloWorld();
}

Next the handcrafted WCF client with constructors and service contract interface implementation:

public class HelloWorldClient : ClientBase<ihelloworldservice>, IHelloWorldService
{
   public HelloWorldClient()
   { }

   public HelloWorldClient(string configurationName) : base(configurationName)
   { }

   public HelloWorldClient(Binding binding, EndpointAddress address) : base(binding, address)
   { }

   public string HelloWorld()
   {
      return Channel.HelloWorld();
   }
}

That’s it.

Now you have full control of the WCF client implementation.

Download the sample application Hello World WCF clients including a handcrafted version

Visiting Microsoft in Johannesburg, South Africa

2009-02-11T20:54:48Z

I live and work in the suburbs of Copenhagen in Denmark, but I’m currently in South Africa on business. While I’m here I might as well visit Microsoft South Africa – I did that today. I attended a presentation of the .Net services by Juval Löwy.

Microsoft South Africa is situated in a nice and fairly new building, as you can see on the picture above.

I was amazed about the level of security – first I had to cleared by the security guards before entering the parking lot. This is not uncommon in South Africa, but very uncommon in Denmark.

Inside in the reception the security check barriers prevent unauthorized people to enter.

When I finally was granted access to the presentation, Microsoft served sodas, pizza and beer!