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• SQL Server and Hyper-V Dynamic Memory Part 2

  - by SQLOS Team

  Part 1 of this series was an introduction and overview of Hyper-V Dynamic Memory. This part looks at SQL Server memory management and how the SQL engine responds to changing OS memory conditions.   Part 2: SQL Server Memory Management As with any Windows process, sqlserver.exe has a virtual address space (VAS) of 4GB on 32-bit and 8TB in 64-bit editions. Pages in its VAS are mapped to pages in physical memory when the memory is committed and referenced for the first time. The collection of VAS pages that have been recently referenced is known as the Working Set. How and when SQL Server allocates virtual memory and grows its working set depends on the memory model it uses. SQL Server supports three basic memory models:   1. Conventional Memory Model   The Conventional model is the default SQL Server memory model and has the following properties: - Dynamic - can grow or shrink its working set in response to load and external (operating system) memory conditions. - OS uses 4K pages – (not to be confused with SQL Server “pages” which are 8K regions of committed memory).- Pageable - Can be paged out to disk by the operating system.   2. Locked Page Model The locked page memory model is set when SQL Server is started with "Lock Pages in Memory" privilege*. It has the following characteristics: - Dynamic - can grow or shrink its working set in the same way as the Conventional model.- OS uses 4K pages - Non-Pageable – When memory is committed it is locked in memory, meaning that it will remain backed by physical memory and will not be paged out by the operating system. A common misconception is to interpret "locked" as non-dynamic. A SQL Server instance using the locked page memory model will grow and shrink (allocate memory and release memory) in response to changing workload and OS memory conditions in the same way as it does with the conventional model.   This is an important consideration when we look at Hyper-V Dynamic Memory – “locked” memory works perfectly well with “dynamic” memory.   * Note in “Denali” (Standard Edition and above), and in SQL 2008 R2 64-bit (Enterprise and above editions) the Lock Pages in Memory privilege is all that is required to set this model. In 2008 R2 64-Bit standard edition it also requires trace flag 845 to be set, in 2008 R2 32-bit editions it requires sp_configure 'awe enabled' 1.   3. Large Page Model The Large page model is set using trace flag 834 and potentially offers a small performance boost for systems that are configured with large pages. It is characterized by: - Static - memory is allocated at startup and does not change. - OS uses large (>2MB) pages - Non-Pageable The large page model is supported with Hyper-V Dynamic Memory (and Hyper-V also supports large pages), but you get no benefit from using Dynamic Memory with this model since SQL Server memory does not grow or shrink. The rest of this article will focus on the locked and conventional SQL Server memory models.   When does SQL Server grow? For “dynamic” configurations (Conventional and Locked memory models), the sqlservr.exe process grows – allocates and commits memory from the OS – in response to a workload. As much memory is allocated as is required to optimally run the query and buffer data for future queries, subject to limitations imposed by:   - SQL Server max server memory setting. If this configuration option is set, the buffer pool is not allowed to grow to more than this value. In SQL Server 2008 this value represents single page allocations, and in “Denali” it represents any size page allocations and also managed CLR procedure allocations.   - Memory signals from OS. The operating system sets a signal on memory resource notification objects to indicate whether it has memory available or whether it is low on available memory. If there is only 32MB free for every 4GB of memory a low memory signal is set, which continues until 64MB/4GB is free. If there is 96MB/4GB free the operating system sets a high memory signal. SQL Server only allocates memory when the high memory signal is set.   To summarize, for SQL Server to grow you need three conditions: a workload, max server memory setting higher than the current allocation, high memory signals from the OS.    When does SQL Server shrink caches? SQL Server as a rule does not like to return memory to the OS, but it will shrink its caches in response to memory pressure. Memory pressure can be divided into “internal” and “external”.   - External memory pressure occurs when the operating system is running low on memory and low memory signals are set. The SQL Server Resource Monitor checks for low memory signals approximately every 5 seconds and it will attempt to free memory until the signals stop.   To free memory SQL Server does the following: ·         Frees unused memory. ·         Notifies Memory Manager Clients to release memory o   Caches – Free unreferenced cache objects. o   Buffer pool - Based on oldest access times.   The freed memory is released back to the operating system. This process continues until the low memory resource notifications stop.    - Internal memory pressure occurs when the size of different caches and allocations increase but the SQL Server process needs to keep its total memory within a target value. For example if max server memory is set and certain caches are growing large, it will cause SQL to free memory for re-use internally, but not to release memory back to the OS. If you lower the value of max server memory you will generate internal memory pressure that will cause SQL to release memory back to the OS.    Memory pressure handling has not changed much since SQL 2005 and it was described in detail in a blog post by Slava Oks.   Note that SQL Server Express is an exception to the above behavior. Unlike other editions it does not assume it is the most important process running on the system but tries to be more “desktop” friendly. It will empty its working set after a period of inactivity.   How does SQL Server respond to changing OS memory?    In SQL Server 2005 support for Hot-Add memory was introduced. This feature, available in Enterprise and above editions, allows the server to make use of any extra physical memory that was added after SQL Server started. Being able to add physical memory when the system is running is limited to specialized hardware, but with the Hyper-V Dynamic Memory feature, when new memory is allocated to a guest virtual machine, it looks like hot-add physical memory to the guest. What this means is that thanks to the hot-add memory feature, SQL Server 2005 and higher can dynamically grow if more “physical” memory is granted to a guest VM by Hyper-V dynamic memory.   SQL Server checks OS memory every second and dynamically adjusts its “target” (based on available OS memory and max server memory) accordingly.   In “Denali” Standard Edition will also have sqlserver.exe support for hot-add memory when running virtualized (i.e. detecting and acting on Hyper-V Dynamic Memory allocations).   How does a SQL Server workload in a guest VM impact Hyper-V dynamic memory scheduling?   When a SQL workload causes the sqlserver.exe process to grow its working set, the Hyper-V memory scheduler will detect memory pressure in the guest VM and add memory to it. SQL Server will then detect the extra memory and grow according to workload demand. In our tests we have seen this feedback process cause a guest VM to grow quickly in response to SQL workload - we are still working on characterizing this ramp-up.    How does SQL Server respond when Hyper-V removes memory from a guest VM through ballooning?   If pressure from other VM's cause Hyper-V Dynamic Memory to take memory away from a VM through ballooning (allocating memory with a virtual device driver and returning it to the host OS), Windows Memory Manager will page out unlocked portions of memory and signal low resource notification events. When SQL Server detects these events it will shrink memory until the low memory notifications stop (see cache shrinking description above).    This raises another question. Can we make SQL Server release memory more readily and hence behave more "dynamically" without compromising performance? In certain circumstances where the application workload is predictable it may be possible to have a job which varies "max server memory" according to need, lowering it when the engine is inactive and raising it before a period of activity. This would have limited applicaability but it is something we're looking into.   What Memory Management changes are there in SQL Server “Denali”?   In SQL Server “Denali” (aka SQL11) the Memory Manager has been re-written to be more efficient. The main changes are summarized in this post. An important change with respect to Hyper-V Dynamic Memory support is that now the max server memory setting includes any size page allocations and managed CLR procedure allocations it now represents a closer approximation to total sqlserver.exe memory usage. This makes it easier to calculate a value for max server memory, which becomes important when configuring virtual machines to work well with Hyper-V Dynamic Memory Startup and Maximum RAM settings.   Another important change is no more AWE or hot-add support for 32-bit edition. This means if you're running a 32-bit edition of Denali you're limited to a 4GB address space and will not be able to take advantage of dynamically added OS memory that wasn't present when SQL Server started (though Hyper-V Dynamic Memory is still a supported configuration).   In part 3 we’ll develop some best practices for configuring and using SQL Server with Dynamic Memory. Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• Error caused by Dropbox in update manager

  - by Olivier Lalonde

  I am getting the following error message when the update manager runs: Apt Authentication issue Problem during package list update. The package list update failed with a authentication failure. This usually happens behind a network proxy server. Please try to click on the "Run this action now" button to correct the problem or update the list manually by running Update Manager and clicking on "Check". W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: http://linux.dropbox.com lucid Release: The following signatures were invalid: NODATA 1 NODATA 2 W: Failed to fetch http://linux.dropbox.com/ubuntu/dists/lucid/Release W: Some index files failed to download, they have been ignored, or old ones used instead. This error started to appear recently and for no obvious reason (maybe because I created myself a private PGP key?). I'm running Dropbox v0.7.11 on Ubuntu Lucid 10.04.

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• Silverlight for Windows Embedded tutorial (step 6)

  - by Valter Minute

  In this tutorial step we will develop a very simple clock application that may be used as a screensaver on our devices and will allow us to discover a new feature of Silverlight for Windows Embedded (transforms) and how to use an “old” feature of Windows CE (timers) inside a Silverlight for Windows Embedded application. Let’s start with some XAML, as usual: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="640" Height="480" FontSize="18" x:Name="Clock">   <Canvas x:Name="LayoutRoot" Background="#FF000000"> <Grid Height="24" Width="150" Canvas.Left="320" Canvas.Top="234" x:Name="SecondsHand" Background="#FFFF0000"> <TextBlock Text="Seconds" TextWrapping="Wrap" Width="50" HorizontalAlignment="Right" VerticalAlignment="Center" x:Name="SecondsText" Foreground="#FFFFFFFF" TextAlignment="Right" Margin="2,2,2,2"/> </Grid> <Grid Height="24" x:Name="MinutesHand" Width="100" Background="#FF00FF00" Canvas.Left="320" Canvas.Top="234"> <TextBlock HorizontalAlignment="Right" x:Name="MinutesText" VerticalAlignment="Center" Width="50" Text="Minutes" TextWrapping="Wrap" Foreground="#FFFFFFFF" TextAlignment="Right" Margin="2,2,2,2"/> </Grid> <Grid Height="24" x:Name="HoursHand" Width="50" Background="#FF0000FF" Canvas.Left="320" Canvas.Top="234"> <TextBlock HorizontalAlignment="Right" x:Name="HoursText" VerticalAlignment="Center" Width="50" Text="Hours" TextWrapping="Wrap" Foreground="#FFFFFFFF" TextAlignment="Right" Margin="2,2,2,2"/> </Grid> </Canvas> </UserControl> This XAML file defines three grid panels, one for each hand of our clock (we are implementing an analog clock using one of the most advanced technologies of the digital world… how cool is that?). Inside each hand we put a TextBlock that will be used to display the current hour, minute, second inside the dial (you can’t do that on plain old analog clocks, but it looks nice). As usual we use XAML2CPP to generate the boring part of our code. We declare a class named “Clock” and derives from the TClock template that XAML2CPP has declared for us. class Clock : public TClock<Clock> { ... }; Our WinMain function is more or less the same we used in all the previous samples. It initializes the XAML runtime, create an instance of our class, initialize it and shows it as a dialog: int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { if (!XamlRuntimeInitialize()) return -1;   HRESULT retcode;   IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return -1; Clock clock;   if (FAILED(clock.Init(hInstance,app))) return -1;     UINT exitcode;   if (FAILED(clock.GetVisualHost()->StartDialog(&exitcode))) return -1;   return exitcode; } Silverlight for Windows Embedded provides a lot of features to implement our UI, but it does not provide timers. How we can update our clock if we don’t have a timer feature? We just use plain old Windows timers, as we do in “regular” Windows CE applications! To use a timer in WinCE we should declare an id for it: #define IDT_CLOCKUPDATE 0x12341234 We also need an HWND that will be used to receive WM_TIMER messages. Our Silverlight for Windows Embedded page is “hosted” inside a GWES Window and we can retrieve its handle using the GetContainerHWND function of our VisualHost object. Let’s see how this is implemented inside our Clock class’ Init method: HRESULT Init(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode;   if (FAILED(retcode=TClock<Clock>::Init(hInstance,app))) return retcode;   // create the timer user to update the clock HWND clockhwnd;   if (FAILED(GetVisualHost()->GetContainerHWND(&clockhwnd))) return -1;   timer=SetTimer(clockhwnd,IDT_CLOCKUPDATE,1000,NULL); return 0; } We use SetTimer to create a new timer and GWES will send a WM_TIMER to our window every second, giving us a chance to update our clock. That sounds great… but how could we handle the WM_TIMER message if we didn’t implement a window procedure for our window? We have to move a step back and look how a visual host is created. This code is generated by XAML2CPP and is inside xaml2cppbase.h: virtual HRESULT CreateHost(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode; XRWindowCreateParams wp;   ZeroMemory(&wp, sizeof(XRWindowCreateParams)); InitWindowParms(&wp);   XRXamlSource xamlsrc;   SetXAMLSource(hInstance,&xamlsrc); if (FAILED(retcode=app->CreateHostFromXaml(&xamlsrc, &wp, &vhost))) return retcode;   if (FAILED(retcode=vhost->GetRootElement(&root))) return retcode; return S_OK; } As you can see the CreateHostFromXaml function of IXRApplication accepts a structure named XRWindowCreateParams that control how the “plain old” GWES Window is created by the runtime. This structure is initialized inside the InitWindowParm method: // Initializes Windows parameters, can be overridden in the user class to change its appearance virtual void InitWindowParms(XRWindowCreateParams* wp) { wp->Style = WS_OVERLAPPED; wp->pTitle = windowtitle; wp->Left = 0; wp->Top = 0; } This method set up the window style, title and position. But the XRWindowCreateParams contains also other fields and, since the function is declared as virtual, we could initialize them inside our version of InitWindowParms: // add hook procedure to the standard windows creation parms virtual void InitWindowParms(XRWindowCreateParams* wp) { TClock<Clock>::InitWindowParms(wp);   wp->pHookProc=StaticHostHookProc; wp->pvUserParam=this; } This method calls the base class implementation (useful to not having to re-write some code, did I told you that I’m quite lazy?) and then initializes the pHookProc and pvUserParam members of the XRWindowsCreateParams structure. Those members will allow us to install a “hook” procedure that will be called each time the GWES window “hosting” our Silverlight for Windows Embedded UI receives a message. We can declare a hook procedure inside our Clock class: // static hook procedure static BOOL CALLBACK StaticHostHookProc(VOID* pv,HWND hwnd,UINT Msg,WPARAM wParam,LPARAM lParam,LRESULT* pRetVal) { ... } You should notice two things here. First that the function is declared as static. This is required because a non-static function has a “hidden” parameters, that is the “this” pointer of our object. Having an extra parameter is not allowed for the type defined for the pHookProc member of the XRWindowsCreateParams struct and so we should implement our hook procedure as static. But in a static procedure we will not have a this pointer. How could we access the data member of our class? Here’s the second thing to notice. We initialized also the pvUserParam of the XRWindowsCreateParams struct. We set it to our this pointer. This value will be passed as the first parameter of the hook procedure. In this way we can retrieve our this pointer and use it to call a non-static version of our hook procedure: // static hook procedure static BOOL CALLBACK StaticHostHookProc(VOID* pv,HWND hwnd,UINT Msg,WPARAM wParam,LPARAM lParam,LRESULT* pRetVal) { return ((Clock*)pv)->HostHookProc(hwnd,Msg,wParam,lParam,pRetVal); } Inside our non-static hook procedure we will have access to our this pointer and we will be able to update our clock: // hook procedure (handles timers) BOOL HostHookProc(HWND hwnd,UINT Msg,WPARAM wParam,LPARAM lParam,LRESULT* pRetVal) { switch (Msg) { case WM_TIMER: if (wParam==IDT_CLOCKUPDATE) UpdateClock(); *pRetVal=0; return TRUE; } return FALSE; } The UpdateClock member function will update the text inside our TextBlocks and rotate the hands to reflect current time: // udates Hands positions and labels HRESULT UpdateClock() { SYSTEMTIME time; HRESULT retcode;   GetLocalTime(&time);   //updates the text fields TCHAR timebuffer[32];   _itow(time.wSecond,timebuffer,10);   SecondsText->SetText(timebuffer);   _itow(time.wMinute,timebuffer,10);   MinutesText->SetText(timebuffer);   _itow(time.wHour,timebuffer,10);   HoursText->SetText(timebuffer);   if (FAILED(retcode=RotateHand(((float)time.wSecond)*6-90,SecondsHand))) return retcode;   if (FAILED(retcode=RotateHand(((float)time.wMinute)*6-90,MinutesHand))) return retcode;   if (FAILED(retcode=RotateHand(((float)(time.wHour%12))*30-90,HoursHand))) return retcode;   return S_OK; } The function retrieves current time, convert hours, minutes and seconds to strings and display those strings inside the three TextBlocks that we put inside our clock hands. Then it rotates the hands to position them at the right angle (angles are in degrees and we have to subtract 90 degrees because 0 degrees means horizontal on Silverlight for Windows Embedded and usually a clock 0 is in the top position of the dial. The code of the RotateHand function uses transforms to rotate our clock hands on the screen: // rotates a Hand HRESULT RotateHand(float angle,IXRFrameworkElement* Hand) { HRESULT retcode; IXRRotateTransformPtr rotatetransform; IXRApplicationPtr app;   if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode;   if (FAILED(retcode=app->CreateObject(IID_IXRRotateTransform,&rotatetransform))) return retcode;     if (FAILED(retcode=rotatetransform->SetAngle(angle))) return retcode;   if (FAILED(retcode=rotatetransform->SetCenterX(0.0))) return retcode;   float height;   if (FAILED(retcode==Hand->GetActualHeight(&height))) return retcode;   if (FAILED(retcode=rotatetransform->SetCenterY(height/2))) return retcode; if (FAILED(retcode=Hand->SetRenderTransform(rotatetransform))) return retcode;   return S_OK; } It creates a IXRotateTransform object, set its rotation angle and origin (the default origin is at the top-left corner of our Grid panel, we move it in the vertical center to keep the hand rotating around a single point in a more “clock like” way. Then we can apply the transform to our UI object using SetRenderTransform. Every UI element (derived from IXRFrameworkElement) can be rotated! And using different subclasses of IXRTransform also moved, scaled, skewed and distorted in many ways. You can also concatenate multiple transforms and apply them at once suing a IXRTransformGroup object. The XAML engine uses vector graphics and object will not look “pixelated” when they are rotated or scaled. As usual you can download the code here: http://cid-9b7b0aefe3514dc5.skydrive.live.com/self.aspx/.Public/Clock.zip If you read up to (down to?) this point you seem to be interested in Silverlight for Windows Embedded. If you want me to discuss some specific topic, please feel free to point it out in the comments! Technorati Tags: Silverlight for Windows Embedded,Windows CE

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• What should be tested in Javascript?

  - by Nathan Hoad

  At work, we've just started on a heavily Javascript based application (actually using Coffeescript, but still), of which I've been implementing an automated test system using JsTestDriver and fabric. We've never written something with this much Javascript, so up until now we've never done any Javascript testing. I'm unsure what exactly we should be testing in our unit tests. We've written JQuery plugins for various things, so it's quite obvious that they should be verified for correctness as much as possible with JsTestDriver, but everyone else in my team seems to think that we should be testing the page level Javascript as well. I don't think we should be testing page level Javascript as unit tests, but instead using a system like Selenium to verify everything works as expected. My main reasoning for this is that at the moment, page level Javascript tests are guaranteed to fail through JsTestDriver, because they're trying to access elements on the DOM that can't possibly exist. So, what should be unit tested in Javascript?

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• Windows Phone 7 review

  - by Jeff

  I finally got around to composing some thoughts on what I think about Windows Phone 7, and I posted those impressions on my personal blog. I'll save a few bytes and not repost it here.It should be obvious that my general impression is overwhelmingly positive. What I don't go into very deeply is how much I enjoy developing stuff for it. Baby Stopwatch was not even remotely hard to build, because it wasn't complex, but also because the platform itself is so easy to deal with. I've been messing around and building something a little more involved, and it too has been fun to work with. Sure, you have the quirks of Silverlight to work out, and then the phone-specific quirks after that, but it really is a lot of fun. If you haven't come up with a science project for the phone, I would encourage you to do so.Now if only I could find a gig here at Microsoft where people just build phone apps all day! (But not games... I know we already do that quite a bit.)

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• Make mex compiler of matlab working on mint?

  - by Erogol

  Mex compiler of matlab does not work with following error Warning: You are using gcc version "4.7.2-2ubuntu1)". The version currently supported with MEX is "4.4.6". For a list of currently supported compilers see: http://www.mathworks.com/support/compilers/current_release/ /home/krm/matlab/bin/mex: 1: eval: g++: not found mex: compile of ' "fv_cache/fv_cache.cc"' failed. it is obvious that I need preceding version of gcc but this specific version is not included in software manager of mint. I installed gcc-4.4 but it does not recognized by Matlab. I also removed latest version from my computer and set gcc as a environment variable points to gcc-4.4 but again does not work. Is there any other way around to solve that issue? Maybe a interface or something.

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• GuestPost: Unit Testing Entity Framework (v1) Dependent Code using TypeMock Isolator

  - by Eric Nelson

  Time for another guest post (check out others in the series), this time bringing together the world of mocking with the world of Entity Framework. A big thanks to Moses for agreeing to do this. Unit Testing Entity Framework Dependent Code using TypeMock Isolator by Muhammad Mosa Introduction Unit testing data access code in my opinion is a challenging thing. Let us consider unit tests and integration tests. In integration tests you are allowed to have environmental dependencies such as a physical database connection to insert, update, delete or retrieve your data. However when performing unit tests it is often much more efficient and productive to remove environmental dependencies. Instead you will need to fake these dependencies. Faking a database (also known as mocking) can be relatively straight forward but the version of Entity Framework released with .Net 3.5 SP1 has a number of implementation specifics which actually makes faking the existence of a database quite difficult. Faking Entity Framework As mentioned earlier, to effectively unit test you will need to fake/simulate Entity Framework calls to the database. There are many free open source mocking frameworks that can help you achieve this but it will require additional effort to overcome & workaround a number of limitations in those frameworks. Examples of these limitations include: Not able to fake calls to non virtual methods Not able to fake sealed classes Not able to fake LINQ to Entities queries (replace database calls with in-memory collection calls) There is a mocking framework which is flexible enough to handle limitations such as those above. The commercially available TypeMock Isolator can do the job for you with less code and ultimately more readable unit tests. I’m going to demonstrate tackling one of those limitations using MoQ as my mocking framework. Then I will tackle the same issue using TypeMock Isolator. Mocking Entity Framework with MoQ One basic need when faking Entity Framework is to fake the ObjectContext. This cannot be done by passing any connection string. You have to pass a correct Entity Framework connection string that specifies CSDL, SSDL and MSL locations along with a provider connection string. Assuming we are going to do that, we’ll explore another limitation. The limitation we are going to face now is related to not being able to fake calls to non-virtual/overridable members with MoQ. I have the following repository method that adds an EntityObject (instance of a Blog entity) to Blogs entity set in an ObjectContext. public override void Add(Blog blog) { if(BlogContext.Blogs.Any(b=>b.Name == blog.Name)) { throw new InvalidOperationException("Blog with same name already exists!"); } BlogContext.AddToBlogs(blog); } The method does a very simple check that the name of the new Blog entity instance doesn’t exist. This is done through the simple LINQ query above. If the blog doesn’t already exist it simply adds it to the current context to be saved when SaveChanges of the ObjectContext instance (e.g. BlogContext) is called. However, if a blog with the same name exits, and exception (InvalideOperationException) will be thrown. Let us now create a unit test for the Add method using MoQ. [TestMethod] [ExpectedException(typeof(InvalidOperationException))] public void Add_Should_Throw_InvalidOperationException_When_Blog_With_Same_Name_Already_Exits() { //(1) We shouldn't depend on configuration when doing unit tests! But, //its a workaround to fake the ObjectContext string connectionString = ConfigurationManager .ConnectionStrings["MyBlogConnString"] .ConnectionString; //(2) Arrange: Fake ObjectContext var fakeContext = new Mock<MyBlogContext>(connectionString); //(3) Next Line will pass, as ObjectContext now can be faked with proper connection string var repo = new BlogRepository(fakeContext.Object); //(4) Create fake ObjectQuery<Blog>. Will be used to substitute MyBlogContext.Blogs property var fakeObjectQuery = new Mock<ObjectQuery<Blog>>("[Blogs]", fakeContext.Object); //(5) Arrange: Set Expectations //Next line will throw an exception by MoQ: //System.ArgumentException: Invalid setup on a non-overridable member fakeContext.SetupGet(c=>c.Blogs).Returns(fakeObjectQuery.Object); fakeObjectQuery.Setup(q => q.Any(b => b.Name == "NewBlog")).Returns(true); //Act repo.Add(new Blog { Name = "NewBlog" }); } This test method is checking to see if the correct exception ([ExpectedException(typeof(InvalidOperationException))]) is thrown when a developer attempts to Add a blog with a name that’s already exists. On (1) a connection string is initialized from configuration file. To retrieve the full connection string. On (2) a fake ObjectContext is being created. The ObjectContext here is MyBlogContext and its being created using this var fakeContext = new Mock<MyBlogContext>(connectionString); This way a fake context is being created using MoQ. On (3) a BlogRepository instance is created. BlogRepository has dependency on generate Entity Framework ObjectContext, MyObjectContext. And so the fake context is passed to the constructor. var repo = new BlogRepository(fakeContext.Object); On (4) a fake instance of ObjectQuery<Blog> is being created to use as a substitute to MyObjectContext.Blogs property as we will see in (5). On (5) setup an expectation for calling Blogs property of MyBlogContext and substitute the return result with the fake ObjectQuery<Blog> instance created on (4). When you run this test it will fail with MoQ throwing an exception because of this line: fakeContext.SetupGet(c=>c.Blogs).Returns(fakeObjectQuery.Object); This happens because the generate property MyBlogContext.Blogs is not virtual/overridable. And assuming it is virtual or you managed to make it virtual it will fail at the following line throwing the same exception: fakeObjectQuery.Setup(q => q.Any(b => b.Name == "NewBlog")).Returns(true); This time the test will fail because the Any extension method is not virtual/overridable. You won’t be able to replace ObjectQuery<Blog> with fake in memory collection to test your LINQ to Entities queries. Now lets see how replacing MoQ with TypeMock Isolator can help. Mocking Entity Framework with TypeMock Isolator The following is the same test method we had above for MoQ but this time implemented using TypeMock Isolator: [TestMethod] [ExpectedException(typeof(InvalidOperationException))] public void Add_New_Blog_That_Already_Exists_Should_Throw_InvalidOperationException() { //(1) Create fake in memory collection of blogs var fakeInMemoryBlogs = new List<Blog> {new Blog {Name = "FakeBlog"}}; //(2) create fake context var fakeContext = Isolate.Fake.Instance<MyBlogContext>(); //(3) Setup expected call to MyBlogContext.Blogs property through the fake context Isolate.WhenCalled(() => fakeContext.Blogs) .WillReturnCollectionValuesOf(fakeInMemoryBlogs.AsQueryable()); //(4) Create new blog with a name that already exits in the fake in memory collection in (1) var blog = new Blog {Name = "FakeBlog"}; //(5) Instantiate instance of BlogRepository (Class under test) var repo = new BlogRepository(fakeContext); //(6) Acting by adding the newly created blog () repo.Add(blog); } When running the above test method it will pass as the Add method of BlogRepository is going to throw an InvalidOperationException which is the expected behaviour. Nothing prevents us from faking out the database interaction! Even faking ObjectContext  at (2) didn’t require a connection string. On (3) Isolator sets up a faking result for MyBlogContext.Blogs when its being called through the fake instance fakeContext created on (2). The faking result is just an in-memory collection declared an initialized on (1). Finally at (6) action we call the Add method of BlogRepository passing a new Blog instance that has a name that’s already exists in the fake in-memory collection which we set up at (1). As expected the test will pass because it will throw the expected exception defined on top of the test method - InvalidOperationException. TypeMock Isolator succeeded in faking Entity Framework with ease. Conclusion We explored how to write a simple unit test using TypeMock Isolator for code which is using Entity Framework. We also explored a few of the limitations of other mocking frameworks which TypeMock is successfully able to handle. There are workarounds that you can use to overcome limitations when using MoQ or Rhino Mock, however the workarounds will require you to write more code and your tests will likely be more complex. For a comparison between different mocking frameworks take a look at this document produced by TypeMock. You might also want to check out this open source project to compare mocking frameworks. I hope you enjoyed this post Muhammad Mosa http://mosesofegypt.net/ http://twitter.com/mosessaur Screencast of unit testing Entity Framework Related Links GuestPost: Introduction to Mocking GuesPost: Typemock Isolator – Much more than an Isolation framework

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• top Tweets SOA Partner Community – August 2012

  - by JuergenKress

  Send your tweets @soacommunity #soacommunity and follow us at http://twitter.com/soacommunity Lucas Jellema ?Published an article about organizing Fusion Middleware Administration: http://technology.amis.nl/2012/07/31/organizing-fusion-middleware-administration-in-a-smart-and-frugal-way … - many organizations are struggling with this. ServiceTechSymposium Countdown to the Early Bird Registration Discount deadline. Only 4 days left! http://ow.ly/cBCiv demed ?Good chatting w Bob Rhubart, Thomas Erl & Tim Hall on SOA & Cloud Symposium https://blogs.oracle.com/archbeat/entry/podcast_show_notes_thomas_erl … @soaschool @OTNArchBeat -- CU in London! SOA Community top Tweets SOA Partner Community July 2012 - are you one of them? If yes please rt! https://soacommunity.wordpress.com/2012/07/30/top-tweets-soa-partner-community-july-2012/ … #soacommunity SOA Community ?Are You a facebook member - do You follow http://www.facebook.com/soacommunity ? #soacommunity #soa SOA Community ?SOA 24/7 - Home Page: http://soa247.com/#.UBJsN8n3kyk.twitter … #soacommunity OracleBlogs ?Handling Large Payloads in SOA Suite 11g http://ow.ly/1lFAih OracleBlogs ?SOA Community Newsletter July 2012 http://ow.ly/1lFx6s OTNArchBeat Podcast Show Notes: Thomas Erl on SOA, Cloud, and Service Technology http://bit.ly/OOHTUJ SOA Community SOA Community Newsletter July 2012 http://wp.me/p10C8u-s7 OTNArchBeat ?OTN ArchBeat Podcast: Thomas Erl on SOA, Cloud, and Service Technology - Part 1 http://pub.vitrue.com/fMti OProcessAccel ?Just released! White Paper: Oracle Process Accelerators Best Practices http://www.oracle.com/technetwork/middleware/bpm/learnmore/processaccelbestpracticeswhitepaper-1708910.pdf … OTNArchBeat ?SOA, Cloud, and Service Technologies - Part 1 of 4 - A conversation with SOA, Cloud, and Service Technology Symposiu... http://ow.ly/1lDyAK OracleBlogs ?SOA Suite 11g PS5 Bundled Patch 3 (11.1.1.6.3) http://ow.ly/1lCW1S Simon Haslam My write-up of the virtues of the #ukoug App Server & Middleware SIG http://bit.ly/LMWdfY What's important to you for our next meeting? SOA Community SOA Partner Community Survey 2012 http://wp.me/p10C8u-qY Simone Geib ?RT @jswaroop: #Oracle positioned in the Leader's quadrant - Gartner Magic Quadrants for Application Infrastructure (SOA & SOA Gov)... ServiceTechSymposium New Supporting Organization, IBTI has joined the Symposium! http://www.servicetechsymposium.com/ orclateamsoa ?A-Team Blog #ateam: BPM 11g Task Form Version Considerations http://ow.ly/1lA7XS OTNArchBeat Oracle content at SOA, Cloud and Service Technology Symposium (and discount code!) http://pub.vitrue.com/FPcW OracleBlogs ?BPM 11g Task Form Version Considerations http://ow.ly/1lzOrX OTNArchBeat BPM 11g #ADF Task Form Versioning | Christopher Karl Chan #fusionmiddleware http://pub.vitrue.com/0qP2 OTNArchBeat Lightweight ADF Task Flow for BPM Human Tasks Overview | @AndrejusB #fusionmiddleware http://pub.vitrue.com/z7x9 SOA Community Oracle Fusion Middleware Summer Camps in Lisbon report by Link Consulting http://middlewarebylink.wordpress.com/2012/07/20/oracle-fusion-middleware-summer-camps-in-lisbon/ … #ofmsummercamps #soa #bpm SOA Community ?Clemens Utschig-Utschig & Manas Deb The Successful Execution of the SOA and BPM Vision Using a Business Capability Framework: Concepts… Simone Geib ?RT @oprocessaccel: Just released! White Paper: Oracle Process Accelerators Best Practices http://www.oracle.com/technetwork/middleware/bpm/learnmore/processaccelbestpracticeswhitepaper-1708910.pdf … jornica ?Report from Oracle Fusion Middleware Summer Camps in Munich: SOA Suite 11g advanced training experiences @soacommunity http://bit.ly/Mw3btE Simone Geib ?Bruce Tierney: Update - SOA & BPM Customer Insights Webcast Series: | https://blogs.oracle.com/SOA/entry/update_soa_bpm_customer_insights … OTNArchBeat Business SOA: Thinking is Dead | @mosesjones http://pub.vitrue.com/k8mw esentri ?had 3 great days in Munich at #Oracle #soacommunity Summercamp! Special thanks to Geoffroy de Lamalle from eProseed! Danilo Schmiedel ?Used my time in train to setup the ps5 soa/bpm vbox-image.Works like a dream. Setup-Readme is perfect! Saves a lot of time!!! @soacommunity 18 Jul SOA Community ?THANKS for the excellent OFM summer camps - save trip home - share your pictures at http://www.facebook.com/soacommunity #ofmsummercamps #soacommunity doors BBQ-party with Oracle @soacommunity. 5Star! #lovemunich #ofmsummercamps pic.twitter.com/ztfcGn2S leonsmiers ?New #Capgemini blog post "Continuous Improvement of Business Agility" http://bit.ly/Lr0EwG #bpm #yam Eric Elzinga ?MDS Explorer utility, http://see.sc/4qdb43 #soasuite ServiceTechSymposium ?@techsymp New speaker Demed L’Her from Oracle has been added to the symposium calendar. http://ow.ly/cjnyw SOA Community ?Last day of the Fusion Middleware summer camps - we continue at 9.00 am. send us your barbecue pictures! #ofmsummercamps #soacommunity SOA Community ?Delivering SOA Governance with EAMS and Oracle Enterprise Repository by Link Consulting http://middlewarebylink.wordpress.com/2012/06/26/delivering-soa-governance-with-eams-and-oracle-enterprise-repository/ … #soacommunity #soa #oer OracleBlogs ?Process Accelerator Kit http://ow.ly/1loaCw 15 Jul SOA Community ?Sun is back in Munich! Send your pictures Middleware summer camps! #ofmsummercamps We start tomorrow 11.00 at Oracle pic.twitter.com/6FStxomk Walter Montantes ?Gracias, Obrigado, Thank you, Danke a Lisboa y a @soacommunity @wlscommunity. From the Mexican guys!! cc @mikeintoch #ofmsummercamps Andrejus Baranovskis Tips & Tricks How to Run Oracle BPM 11g PS5 Workspace from Custom ADF 11g Application http://fb.me/1zOf3h2K8 JDeveloper & ADF ?Fusion Apps Enterprise Repository - Explained http://dlvr.it/1rpjWd Steve Walker ?Oracle #Exalogic is the logical choice for running business applications. Exalogic Software 2.0 launches 7/25. Reg at http://bit.ly/NedQ9L A. Chatziantoniou ?Landed in rainy Amsterdam after a great week in Lisbon for the #ofmsummercamps - multo obrigado for Jürgen for another fantastic event SOA Community ?Teams present #BPM11g POC results at #ofmsummercamps - great job! #soacommunity pic.twitter.com/0d4txkWF Sabine Leitner ?#DOAG SIG Middleware 29.08.2012 Köln über MW, Administration, Monitoring http://bit.ly/P47w82 @soacommunity @OracleMW @OracleFMW 12 Jul philmulhall ?Thanks @soacommunity for a great week at the #ofmsummercamps. Hard work done so time for a few cold ones in Lisboa. pic.twitter.com/LVUUuwTh peter230769 ?RT: andrea_rocco_31: RT @soacommunity: Enjoy the networking event at #ofmsummercamps want to attend next time ... pic.twitter.com/D1HRndi4 Niels Gorter ?#ofmsummercamps dinner in Lisbon. Great weather, scenery, training, people, on and on. Big THANKS @soacommunity JDeveloper & ADF ?Running Oracle BPM 11g PS5 Worklist Task Flow and Human Task Form on Non-SOA Domain http://dlvr.it/1r0c2j Andrea Rocco ?RT @soacommunity: Jamy pastry at cafe Belem - who is the ghost there?!? http://via.me/-2x33uk6 Simon Haslam ?Sounds great - sorry I couldn't make it. RT @soacommunity: 6pm BPM advanced training hard work to build the POC #ofmsummercamps philmulhall ?A well earned rest after a hard days work @soacommunity #summercamps pic.twitter.com/LKK7VOVS philmulhall ?Some more hard working delegates @soacommunity #summercamps pic.twitter.com/gWpk1HZh SOA Community ?Error message at the BPM POC - will The #ace director understand the message and solve it? #ofmsummercamps pic.twitter.com/LFTEzNck Daniel Kleine-Albers ?posted on the #thecattlecrew blog: Assigning more memory to JDeveloper http://thecattlecrew.wordpress.com/2012/07/10/jdeveloper-quicktip-assigning-more-memory/ … OTNArchBeat ?BAM design pointers | Kavitha Srinivasan http://pub.vitrue.com/TOhP SOA Community ?Did you receive the July SOA community newsletter? read it! Want to become a member http://www.oracle.com/goto/emea/soa #soacommunity #soa #opn OracleBlogs ?Markus Zirn, Big Data with CEP and SOA @ SOA, Cloud &amp; Service Technology Symposium 2012 http://ow.ly/1lcSkb Andrejus Baranovskis Running Oracle BPM 11g PS5 Worklist Task Flow and Human Task Form on Non-SOA Eric Elzinga ?Service Facade design pattern in OSB, http://bit.ly/NnOExN Eric Elzinga ?New BPEL Thread Pool in SOA 11g for Non-Blocking Invoke Activities from 11.1.1.6 (PS5), http://bit.ly/NnOc2G Gilberto Holms New Post: Siebel Connection Pool in Oracle Service Bus 11g http://wp.me/pRE8V-2z Oracle UPK & Tutor ?UPK Pre-Built Content Update: UPK pre-built content development efforts are always underway and growing. Ove... http://bit.ly/R2HeTj JDeveloper & ADF ?Troubleshooting BPMN process editor problems in 11.1.1.6 http://dlvr.it/1p0FfS orclateamsoa ?A-Team Blog #ateam: BAM design pointers - In working recently with a large Oracle customer on SOA and BAM, I discove... http://ow.ly/1kYqES SOA Community BPMN process editor problems in 11.1.1.6 by Mark Nelson http://redstack.wordpress.com/2012/06/27/bpmn-process-editor-problems-in-11-1-1-6 … #soacommunity #bpm OTNArchBeat ?SOA Learning Library: free short, topic-focused training on Oracle SOA & BPM products | @SOACommunity http://pub.vitrue.com/NE1G Andrejus Baranovskis ?ADF 11g PS5 Application with Customized BPM Worklist Task Flow (MDS Seeded Customization) http://fb.me/1coX4r1X1 OTNArchBeat ?A Universal JMX Client for Weblogic –Part 1: Monitoring BPEL Thread Pools in SOA 11g | Stefan Koser http://pub.vitrue.com/mQVZ OTNArchBeat ?BPM – Disable DBMS job to refresh B2B Materialized View | Mark Nelson http://pub.vitrue.com/3PR0 SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA Community twitter,SOA Community,Oracle SOA,Oracle BPM,BPM Community,OPN,Jürgen Kress

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• The Presentation Secrets of Steve Jobs

  - by guybarrette

  A few years go, I got interested in presentation styles after reading Cliff Atkinson’s Beyond Bullet Points book.  At that time, it was obvious that the Microsoft presentation culture was kind of missing the point by having far too many bullet points. I recently picked up Carmine Gallo’s The Presentation Secrets of Steve Jobs.  I enjoyed this short read (238 pages) book full of presentation tips.  The best advise that I got from reading this book is that you must have an antagonist in your presentation.  This will help the audience visualize and understand the problem (antagonist) and the solution (what you present).  When presenting a technical topic, it is easy to forget to explain what problem is being solved by using this new technology/technique/pattern/API. This is a great read for anyone giving presentations, technical or not.     var addthis_pub="guybarrette";

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• The Presentation Secrets of Steve Jobs

  A few years go, I got interested in presentation styles after reading Cliff Atkinsons Beyond Bullet Points book.  At that time, it was obvious that the Microsoft presentation culture was kind of missing the point by having far too many bullet points. I recently picked up Carmine Gallos The Presentation Secrets of Steve Jobs.  I enjoyed this short read (238 pages) book full of presentation tips.  The best advise that I got from reading this book is that you must have an antagonist...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• BizTalk host throttling &ndash; Singleton pattern and High database size

  - by S.E.R.

  Originally posted on: http://geekswithblogs.net/SERivas/archive/2013/06/30/biztalk-host-throttling-ndash-singleton-pattern-and-high-database-size.aspxI have worked for some days around the singleton pattern (for those unfamiliar with it, read this post by Victor Fehlberg) and have come across a few very interesting posts, among which one dealt with performance issues (here, also by Victor Fehlberg). Simply put: if you have an orchestration which implements the singleton pattern, then performances will continuously decrease as the orchestration receives and consumes messages, and that behavior is more obvious when the orchestration never ends (ie : it keeps looping and never terminates or completes). As I experienced the same kind of problem (actually I was alerted by SCOM, which told me that the host was being throttled because of High database size), I thought it would be a good idea to dig a little bit a see what happens deep inside BizTalk and thus understand the reasons for this behavior. NOTE: in this article, I will focus on this High database size throttling condition. I will try and work on the other conditions in some not too distant future… Test conditions The singleton orchestration For the purpose of this study, I have created the following orchestration, which is a very basic implementation of a singleton that piles up incoming messages, then does something else when a certain timeout has been reached without receiving another message: Throttling settings I have two distinct hosts : one that hosts the receive port (basic FILE port) : Ports_ReceiveHostone that hosts the orchestration : ProcessingHost In order to emphasize the throttling mechanism, I have modified the throttling settings for each of these hosts are as follows (all other parameters are set to the default value): [Throttling thresholds] Message count in database: 500 (default value : 50000) Evolution of performance counters when submitting messages Since we are investigating the High database size throttling condition, here are the performance counter that we should take a look at (all of them are in the BizTalk:Message Agent performance object): Database sizeHigh database sizeMessage delivery throttling stateMessage publishing throttling stateMessage delivery delay (ms)Message publishing delay (ms)Message delivery throttling state durationMessage publishing throttling state duration (If you are not used to Perfmon, I strongly recommend that you start using it right now: it is a wonderful tool that allows you to open the hood and see what is going on inside BizTalk – and other systems) Database size It is quite obvious that we will start by watching the database size and high database size counters, just to see when the first reaches the configured threshold (500) and when the second rings the alarm. NOTE : During this test I submitted 600 messages, one message at a time every 10ms to see the evolution of the counters we have previously selected. It might not show very well on this screenshot, but here is what happened: From 15:46:50 to 15:47:50, the database size for the Ports_ReceiveHost host (blue line) kept growing until it reached a maximum of 504.At 15:47:50, the high database size alert fires At first I was surprised by this result: why is it the database size of the receiving host that keeps growing since it is the processing host that piles up messages? Actually, it makes total sense. This counter measures the size of the database queue that is being filled by the host, not consumed. Therefore, the high database size alert is raised on the host that fills the queue: Ports_ReceiveHost. More information is available on the Public MPWiki page. Now, looking at the Message publishing throttling state for the receiving host (green line), we can see that a throttling condition has been reached at 15:47:50: We can also see that the Message publishing delay(ms) (blue line) has begun growing slowly from this point. All of this explains why performances keep decreasing when a singleton keeps processing new messages: the database size grows and when it has exceeded the Message count in database threshold, the host is throttled and the publishing delay keeps increasing. Digging further So, what happens to the database queue then? Is it flushed some day or does it keep growing and growing indefinitely? The real question being: will the host be throttled forever because of this singleton? To answer this question, I set the Message count in database threshold to 20 (this value is very low in order not to wait for too long, otherwise I certainly would have fallen asleep in front of my screen) and I submitted 30 messages. The test was started at 18:26. At 18:56 (ie : exactly 30min later) the throttling was stopped and the database size was divided by 2. 30 min later again, the database size had dropped to almost zero: I guess I’ll have to find some documentation and do some more testing before I sort this out! My guess is that some maintenance job is at work here, though I cannot tell which one Digging even further If we take a look at the Message delivery throttling state counter for the processing host, we can see that this host was also throttled during the submission of the 600 documents: The value for the counter was 1, meaning that Message delivery incoming rate for the host instance exceeds the Message delivery outgoing rate * the specified Rate overdrive factor (percent) value. We will see this another day… :) A last word Let’s end this article with a warning: DO NOT CHANGE THE THROTTLING SETTINGS LIGHTLY! The temptation can be great to just bypass throttling by setting very high values for each parameter (or zero in some cases, which simply disables throttling). Nevertheless, always keep in mind that this mechanism is here for a very good reason: prevent your BizTalk infrastructure from exploding!! So whatever you do with those settings, do a lot of testing and benchmarking!

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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• Copying Columns from Grid to Clipboard in SQL Developer

  - by thatjeffsmith

  There are several ways to get data from a query or a table|view to the clipboard. You know the tried and true, copy and paste. But what if you only want one or more columns, not every column? There are several ways to do this, let’s see if we can’t identify all of them. Write your query to only include the data you want Obvious? Yes. Needed to be said? Definitely. The best tuning tip is to only ask for the data you need, only when you absolutely need it. But let’s look at a few more practical ways to do this. Hide the unwanted columns Mouse right click on an column header. In the context menu, select ‘Columns.’ Hide the columns you don’t want. Copy and paste. WYSIWYG Grids, Hide Columns and Filter Rows Mouse select the columns Obvious, but a bit painful. For a very large dataset, you’ll be holding down the Shift and PageDown buttons – but it works. Remember to use Ctrl+Shift+C to get the column headers with the data. Use the Export Wizard This used to be called ‘Unload’ – agreed, not a great name. So, we changed it. In a grid, right mouse click on the data, and on the context menu, select ‘Export…’ Select your format – I suggest ‘delimited’ or ‘fixed’ for copying data to the clipboard. You can export to the clipboard, yes you can! Click ‘Next.’ Click in the Columns dialog, and choose the columns you want copied. Trim the columns you don't want copied Click ‘Finish.’ Alt or Ctrl tab to your window or application of choice. And Paste! "FIRST_NAME" "LAST_NAME" "Donald" "OConnell" "Douglas" "Grant" "Jennifer" "Whalen" "Pat" "Fay" "Susan" "Mavris" "William" "Gietz" "Alexander" "Hunold" "Bruce" "Ernst" "David" "Austin" "Valli" "Pataballa" "Diana" "Lorentz" "Daniel" "Faviet" "John" "Chen" "Ismael" "Sciarra" "Jose Manuel" "Urman" "Luis" "Popp" "Alexander" "Khoo" "Shelli" "Baida" "Sigal" "Tobias" "Guy" "Himuro" "Karen" "Colmenares" "Matthew" "Weiss" "Adam" "Fripp" "Payam" "Kaufling" "Shanta" "Vollman" "Kevin" "Mourgos" "Julia" "Nayer" "Irene" "Mikkilineni" ... There’s probably at least 2 or 3 more ways, but… But, try these and let me know how we can improve things. I’ve already gotten a request to be able to include the SQL text used to populate the dataset on the the copy to clipboard, and it’s now on our to-do list

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• How To Disable the Amazon Search Ads in Ubuntu’s Unity Dash

  - by Chris Hoffman

  Upgrade to Ubuntu 12.10 (Quantal Quetzal) and you’ll run into a surprise – Ubuntu now shows you advertisements for Amazon products when you search in your dash. There’s also an Amazon shortcut pinned to Unity’s launcher. There are several ways to disable these ads, and they aren’t immediately obvious. However, you can easily disable the Amazon search results if you don’t want to see them, or if you’re concerned about the privacy implications. What To Do If You Get a Virus on Your Computer Why Enabling “Do Not Track” Doesn’t Stop You From Being Tracked HTG Explains: What is the Windows Page File and Should You Disable It?

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• What happens to C# 4 optional parameters when compiling against 3.5?

  Heres a method declaration that uses optional parameters: public Path Copy( Path destination, bool overwrite = false, bool recursive = false) Something you may not know is that Visual Studio 2010 will let you compile this against .NET 3.5, with no error or warning. You may be wondering (as I was) how it does that. Well, it takes the easy and rather obvious way of not trying to be too smart and just ignores the optional parameters. So if youre compiling against 3.5 from Visual Studio 2010,...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• How to block internet access for wine applications?

  - by YSN

  Hello! Is it possible to prevent specific wine applications or any wine application from accessing the internet? When using certain apps under Windows, they were trying to access the internet from time to time without any obvious reason. I was able to prevent that behaviour with a personal firewall back then. Unfortunately I did not find an application level firewall in Ubuntu up to now. This is especially annoying when I am abroad using data-roaming with my 3G modem. Is there a way to prevent my wine-apps sending or receiving data without my knowledge. Thanks in advance! YSN

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• Inside the Concurrent Collections: ConcurrentBag

  - by Simon Cooper

  Unlike the other concurrent collections, ConcurrentBag does not really have a non-concurrent analogy. As stated in the MSDN documentation, ConcurrentBag is optimised for the situation where the same thread is both producing and consuming items from the collection. We'll see how this is the case as we take a closer look. Again, I recommend you have ConcurrentBag open in a decompiler for reference. Thread Statics ConcurrentBag makes heavy use of thread statics - static variables marked with ThreadStaticAttribute. This is a special attribute that instructs the CLR to scope any values assigned to or read from the variable to the executing thread, not globally within the AppDomain. This means that if two different threads assign two different values to the same thread static variable, one value will not overwrite the other, and each thread will see the value they assigned to the variable, separately to any other thread. This is a very useful function that allows for ConcurrentBag's concurrency properties. You can think of a thread static variable: [ThreadStatic] private static int m_Value; as doing the same as: private static Dictionary<Thread, int> m_Values; where the executing thread's identity is used to automatically set and retrieve the corresponding value in the dictionary. In .NET 4, this usage of ThreadStaticAttribute is encapsulated in the ThreadLocal class. Lists of lists ConcurrentBag, at its core, operates as a linked list of linked lists: Each outer list node is an instance of ThreadLocalList, and each inner list node is an instance of Node. Each outer ThreadLocalList is owned by a particular thread, accessible through the thread local m_locals variable: private ThreadLocal<ThreadLocalList<T>> m_locals It is important to note that, although the m_locals variable is thread-local, that only applies to accesses through that variable. The objects referenced by the thread (each instance of the ThreadLocalList object) are normal heap objects that are not specific to any thread. Thinking back to the Dictionary analogy above, if each value stored in the dictionary could be accessed by other means, then any thread could access the value belonging to other threads using that mechanism. Only reads and writes to the variable defined as thread-local are re-routed by the CLR according to the executing thread's identity. So, although m_locals is defined as thread-local, the m_headList, m_nextList and m_tailList variables aren't. This means that any thread can access all the thread local lists in the collection by doing a linear search through the outer linked list defined by these variables. Adding items So, onto the collection operations. First, adding items. This one's pretty simple. If the current thread doesn't already own an instance of ThreadLocalList, then one is created (or, if there are lists owned by threads that have stopped, it takes control of one of those). Then the item is added to the head of that thread's list. That's it. Don't worry, it'll get more complicated when we account for the other operations on the list! Taking & Peeking items This is where it gets tricky. If the current thread's list has items in it, then it peeks or removes the head item (not the tail item) from the local list and returns that. However, if the local list is empty, it has to go and steal another item from another list, belonging to a different thread. It iterates through all the thread local lists in the collection using the m_headList and m_nextList variables until it finds one that has items in it, and it steals one item from that list. Up to this point, the two threads had been operating completely independently. To steal an item from another thread's list, the stealing thread has to do it in such a way as to not step on the owning thread's toes. Recall how adding and removing items both operate on the head of the thread's linked list? That gives us an easy way out - a thread trying to steal items from another thread can pop in round the back of another thread's list using the m_tail variable, and steal an item from the back without the owning thread knowing anything about it. The owning thread can carry on completely independently, unaware that one of its items has been nicked. However, this only works when there are at least 3 items in the list, as that guarantees there will be at least one node between the owning thread performing operations on the list head and the thread stealing items from the tail - there's no chance of the two threads operating on the same node at the same time and causing a race condition. If there's less than three items in the list, then there does need to be some synchronization between the two threads. In this case, the lock on the ThreadLocalList object is used to mediate access to a thread's list when there's the possibility of contention. Thread synchronization In ConcurrentBag, this is done using several mechanisms: Operations performed by the owner thread only take out the lock when there are less than three items in the collection. With three or greater items, there won't be any conflict with a stealing thread operating on the tail of the list. If a lock isn't taken out, the owning thread sets the list's m_currentOp variable to a non-zero value for the duration of the operation. This indicates to all other threads that there is a non-locked operation currently occuring on that list. The stealing thread always takes out the lock, to prevent two threads trying to steal from the same list at the same time. After taking out the lock, the stealing thread spinwaits until m_currentOp has been set to zero before actually performing the steal. This ensures there won't be a conflict with the owning thread when the number of items in the list is on the 2-3 item borderline. If any add or remove operations are started in the meantime, and the list is below 3 items, those operations try to take out the list's lock and are blocked until the stealing thread has finished. This allows a thread to steal an item from another thread's list without corrupting it. What about synchronization in the collection as a whole? Collection synchronization Any thread that operates on the collection's global structure (accessing anything outside the thread local lists) has to take out the collection's global lock - m_globalListsLock. This single lock is sufficient when adding a new thread local list, as the items inside each thread's list are unaffected. However, what about operations (such as Count or ToArray) that need to access every item in the collection? In order to ensure a consistent view, all operations on the collection are stopped while the count or ToArray is performed. This is done by freezing the bag at the start, performing the global operation, and unfreezing at the end: The global lock is taken out, to prevent structural alterations to the collection. m_needSync is set to true. This notifies all the threads that they need to take out their list's lock irregardless of what operation they're doing. All the list locks are taken out in order. This blocks all locking operations on the lists. The freezing thread waits for all current lockless operations to finish by spinwaiting on each m_currentOp field. The global operation can then be performed while the bag is frozen, but no other operations can take place at the same time, as all other threads are blocked on a list's lock. Then, once the global operation has finished, the locks are released, m_needSync is unset, and normal concurrent operation resumes. Concurrent principles That's the essence of how ConcurrentBag operates. Each thread operates independently on its own local list, except when they have to steal items from another list. When stealing, only the stealing thread is forced to take out the lock; the owning thread only has to when there is the possibility of contention. And a global lock controls accesses to the structure of the collection outside the thread lists. Operations affecting the entire collection take out all locks in the collection to freeze the contents at a single point in time. So, what principles can we extract here? Threads operate independently Thread-static variables and ThreadLocal makes this easy. Threads operate entirely concurrently on their own structures; only when they need to grab data from another thread is there any thread contention. Minimised lock-taking Even when two threads need to operate on the same data structures (one thread stealing from another), they do so in such a way such that the probability of actually blocking on a lock is minimised; the owning thread always operates on the head of the list, and the stealing thread always operates on the tail. Management of lockless operations Any operations that don't take out a lock still have a 'hook' to force them to lock when necessary. This allows all operations on the collection to be stopped temporarily while a global snapshot is taken. Hopefully, such operations will be short-lived and infrequent. That's all the concurrent collections covered. I hope you've found it as informative and interesting as I have. Next, I'll be taking a closer look at ThreadLocal, which I came across while analyzing ConcurrentBag. As you'll see, the operation of this class deserves a much closer look.

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• What kinds of low level knowledge matter?

  - by Peter Smith

  I realize that this question is similar to Low level programming - what's in it for me, but the answers didn't really address my question well. Part from just an understanding, how exactly does your low level knowledge translate into faster and better programs? There's the obvious lack of garbage collection, but what else is an advantage? Do you really outperform your optimizing compiler? Do you pack your data structures in as tight as possible and be concerned about alignment? There's extra freedom naturally, but does that really translate into a faster program?

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• Unit testing is… well, flawed.

  - by Dewald Galjaard

  Hey someone had to say it. I clearly recall my first IT job. I was appointed Systems Co-coordinator for a leading South African retailer at store level. Don’t get me wrong, there is absolutely nothing wrong with an honest day’s labor and in fact I highly recommend it, however I’m obliged to refer to the designation cautiously; in reality all I had to do was monitor in-store prices and two UNIX front line controllers. If anything went wrong – I only had to phone it in… Luckily that wasn’t all I did. My duties extended to some other interesting annual occurrence – stock take. Despite a bit more curious affair, it was still a tedious process that took weeks of preparation and several nights to complete.  Then also I remember that no matter how elaborate our planning was, the entire exercise would be rendered useless if we couldn’t get the basics right – that being the act of counting. Sounds simple right? We’ll with a store which could potentially carry over tens of thousands of different items… we’ll let’s just say I believe that’s when I first became a coffee addict. In those days the act of counting stock was a very humble process. Nothing like we have today. A staff member would be assigned a bin or shelve filled with items he or she had to sort then count. Thereafter they had to record their findings on a complementary piece of paper. Every night I would manage several teams. Each team was divided into two groups - counters and auditors. Both groups had the same task, only auditors followed shortly on the heels of the counters, recounting stock levels, making sure the original count correspond to their findings. It was a simple yet hugely responsible orchestration of people and thankfully there was one fundamental and golden rule I could always abide by to ensure things run smoothly – No-one was allowed to audit their own work. Nope, not even on nights when I didn’t have enough staff available. This meant I too at times had to get up there and get counting, or have the audit stand over until the next evening. The reason for this was obvious - late at night and with so much to do we were prone to make some mistakes, then on the recount, without a fresh set of eyes, you were likely to repeat the offence. Now years later this rule or guideline still holds true as we develop software (as far removed as software development from counting stock may be). For some reason it is a fundamental guideline we’re simply ignorant of. We write our code, we write our tests and thus commit the same horrendous offence. Yes, the procedure of writing unit tests as practiced in most development houses today – is flawed. Most if not all of the tests we write today exercise application logic – our logic. They are based on the way we believe an application or method should/may/will behave or function. As we write our tests, our unit tests mirror our best understanding of the inner workings of our application code. Unfortunately these tests will therefore also include (or be unaware of) any imperfections and errors on our part. If your logic is flawed as you write your initial code, chances are, without a fresh set of eyes, you will commit the same error second time around too. Not even experience seems to be a suitable solution. It certainly helps to have deeper insight, but is that really the answer we should be looking for? Is that really failsafe? What about code review? Code review is certainly an answer. You could have one developer coding away and another (or team) making sure the logic is sound. The practice however has its obvious drawbacks. Firstly and mainly it is resource intensive and from what I’ve seen in most development houses, given heavy deadlines, this guideline is seldom adhered to. Hardly ever do we have the resources, money or time readily available. So what other options are out there? A quest to find some solution revealed a project by Microsoft Research called PEX. PEX is a framework which creates several test scenarios for each method or class you write, automatically. Think of it as your own personal auditor. Within a few clicks the framework will auto generate several unit tests for a given class or method and save them to a single project. PEX help to audit your work. It lends a fresh set of eyes to any project you’re working on and best of all; it is cost effective and fast. Check them out at http://research.microsoft.com/en-us/projects/pex/ In upcoming posts we’ll dive deeper into how it works and how it can help you.   Certainly there are more similar frameworks out there and I would love to hear from you. Please share your experiences and insights.

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• How can I accept the agreement for ttf-mscorefonts-installer?

  - by Magic

  After a recent update, ttf-mscorefonts-installer prompted me to accept its license agreement. For some reason my terminal will not allow me to accept, or for some reason I am pressing the wrong hotkey... I've tried every letter on the keyboard and Enter among others... I'm sure there is a very simple and obvious solution to this. I've also just tried to remove the package completely however the terminal states that due to the package not being correctly installed, I should reinstall the package before removing it. Very frustrating! Essentially, because I cannot successfully install this package, I can't really ever upgrade my system because I always have to end up terminating the terminal with the license agreement (thus the upgrade fails).

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• CodePlex Daily Summary for Friday, April 23, 2010

  CodePlex Daily Summary for Friday, April 23, 2010New Projects3D TagCloud for SharePoint 2010: 3D Flash TagCloud WebPart for SharePoint 2010AnyCAD.Net: AnyCAD.NetCassandraemon: Cassandraemon is LINQ Provider for Apache Cassandra.CCLI SongSelect Importer for PowerPoint: CCLI SongSelect Importer for PowerPoint ® is an Add-in for Microsoft ® PowerPoint ® that allows CCLI SongSelect (USR) files to be turned into slide...Compactar Arquivo Txt, Flat File, em Pipeline Decoder Customizado: Objetivo do projeto: Desenvolver um componente do tipo Pipeline Receiver Decoder, onde compacta o conteúdo, cria uma mensagem em XML e transforma ...Console Calculator: Console calculator is a simple, yet useful, mathematical expression calculator, supporting functions and variables. It was created to demonstrate ...CRM Dynamics Excel Importer: CRM Dynamics Excel Importercubace: The standard audio composer software with just single difference: this is CLR compilation.deneb: deneb projectDrive Backup: Drive Backup is an easy to use, automatic backup program. Simply insert a USB drive, and the program will backup either files on the drive to your ...eWebMVCCMS: this is the start of eWeb MVC CMS.Fix.ly: Small app that allows for URL rewriting before passing to the browser. Accepts MEF plugins that make themselves available by informing the applicat...GArphics: GArphics uses a genetic algorithm to produce graphics and animation with the assitance of the user.JDS Toolkit: An experimental toolkit geared to make richer applications with less effort. It will include controls such as the cubeoid and the serializedmenu. ...KrashSRC - MapleStory v.75 Emulator: KrashSRC - MapleStory v.75 EmulatorLast.fm Api: Last.fm api writen in Visaul Basic 2010.MIX 10 DVR and Downloader: A Silverlight application that will manage downloading the sessions and slide decks from the MIX '10 Conference utilizing the MIX OData feed for in...NSIS Autorun: This is a graphical CD/DVD/USB autorun engine that launches installers made with NSIS. Non-rectangular windows and animation are supported. Can be ...Pillbox: Windows Phone 7 sample application for tracking medications.PowerSharp: Very simple application that executes a snippet of PowerShell against C#. This will eventually be used with Live@EDU.Project Halosis: mmorpgProyecto Cero: Proyecto CeroSharePoint XSL Templates: This project is a place to share useful XSL templates that can be reused in SharePoint CQWPs and DVWPs.Silverlight 4.0 Popup Menu: Silverlight 4.0 Popup Menu spsearch: This project provides useful enhancements to Search using the SharePoint platform.StereoVision: StereVision es un proyecto que estudia un algoritmo de visión estereocopicaThe Stoffenmanager: The Stoffenmanager is a tool for prioritizing worker health risks to dangerous substances. But also a quantitative inhalation exposure tool and a ...Transcriber: Transcribe text from one character set to another. Extensible, plug-in based architecture. Default plug-in uses XML rules files with regular expres...Wavelets experiments: эксперименты с вейвлетамиWindows Phone 7 World of Warcraft Armory Browser: A test project to learn a little about Windows Phone development and do a decent armory browserXAML Based Chat: Xaml based chat. A simple chat systemNew Releases#Nose: SharpNose v1.1: Configuration is now done by updating SharpNose.exe.config MEF support added - you can also add your favorite test framework discovery Two tes...Baml Localizer: Version 0.1 (alpha): This is the first release which should show the capabilities of Baml Localizer. The code might still change a lot, but the file formats should be q...BibWord : Microsoft Word Citation and Bibliography styles: APA with DOI - Proof of Concept: IntroductionThis release is a proof of concept (POC) demonstrating a possible way of adding a digital object identifier (DOI) field to the APA styl...Chargify.NET: Chargify.NET v0.685: Releasing Version 0.685 - Changed customer reference ID from Guid to String for systems that don't use Guid as the unique key. - Added method for g...Compactar Arquivo Txt, Flat File, em Pipeline Decoder Customizado: SampleZipDecodePipeline: Solution contem Projeto com o Decoder Pipeline. Projeto para usar o Componente. Classes SharpZipLib para compactar e descompactar arquivosConsole Calculator: Console Calculator: Initial source code release.CSharp Intellisense: V1.6: UPDATE: 2010/04/05: description was added 2010/04/07: single selection + reset filter 20010/04/15: source code available at http://csharpintellis...Drive Backup: Drive Backup: Drive Backup allows you to automatically backup a USB device to your computer, or backup files/directories on your computer to a USB. Once you have...Event Scavenger: Thread recycling changes - Version 3.1: Change the location of where the settings for thread recycling is stored - Moved from config file to database for easier management. Version of dat...Extend SmallBasic: Teaching Extensions v.013: Added Houses QuizExtend SmallBasic: Teaching Extensions v.014: fixed a bug in Tortoise.approve rearranged the Houses Quiz to be more funFix.ly: Fix.ly 0.1: Initial test releaseFix.ly: Fix.ly 0.11: Fixed a couple bugs, including missing files in the previous releaseGArphics: Beta: This is the beta-version of the program. Version 1.0 shall be relased soon and will include a lot of improvements.HouseFly: HouseFly alpha 0.2.0.5: HouseFly alpha release 0.2.0.5HouseFly controls: HouseFly controls alpha 0.9.4: Version 0.9.4 alpha release of HouseFly controlsHTML Ruby: 6.21.8: Change Math.floor to round for text spacingHTML Shot: 0.1: Solved problems with some URLsJDS Toolkit: JDS Toolkit 0.1: Beta 0.1 version. Almost nothing in these librariesManaged Extensibility Framework: WebForms and MEF Sample: This sample demonstrates the use of these two technologies together in a non-invasive way. Information on how to use it on your own projects is inc...Microsoft - Domain Oriented N-Layered .NET 4.0 App Sample (Microsoft Spain): V0.7 - N-Layer DDD Sample App (VS.2010 RTM compat): Required Software (Microsoft Base Software needed for Development environment) Visual Studio 2010 RTM & .NET 4.0 RTM (Final Versions) Unity Applic...MvcContrib Portable Areas: Portable Areas: First Release of some portable areasNSIS Autorun: NSIS Autorun: Initial release.OgmoXNA: OgmoXNA Alpha Source Tree: Zipped version of the source tree in case you don't want to go through the SVN!Particle Plot Pivot: Particle Plot Pivot v1.0.0: Generates a Pivot collection of unpublished plots from the particle physics exeriments DZERO, CDF, ATLAS, and CMS. It can be found at http://deepta...patterns & practices SharePoint Guidance: SPG2010 Drop9: SharePoint Guidance Drop Notes Microsoft patterns and practices ****************************************** ***************************************...Rich Ajax empowered Web/Cloud Applications: 6.3.15: New Visual WebGui rich applications platform versionSilverlight 4.0 Popup Menu: PopupMenu for Silverlight 4: This is the first release of the popup menu class for Silverlight 4.0Silverlight Flow Layouts library: SL and WPF Flow Layouts library April 2010: This release introduces WPF 4.0 RTM and Silverlight 4 RTM support, as well as an additional layout algorithm and some minor bug fixes. Some changes...Spackle.NET: 3.0.0.0 Release: In this release: Spackle.dll now targets the 4.0 version of the .NET Framework SecureRandom implements IDisposable ActionExtensions have been ...Splinger FrameXi: Splinger 1.1: Welcome to a whole new way of learning! Go to release 1.0 for the non .zip packaged files.SQL Server Metadata Toolkit 2008: SQL Server Metadata Toolkit Alpha 6: This release addresses issues 10665, 10678 and 10679. The SQL Parser now understands CAST functions (the AS was causing issues), and is installed ...Star Trooper for XNA 2D Tutorial: Lesson four content: Here is Lesson four original content for the StarTrooper 2D XNA tutorial. It also includes the XNA version of Lesson four source. The blog tutori...Thales Simulator Library: Version 0.8.6: The Thales Simulator Library is an implementation of a software emulation of the Thales (formerly Zaxus & Racal) Hardware Security Module cryptogra...Transcriber: Transcriber v0.1: Initial alpha release. Very nearly useful. :-) This version includes rules files for Mode of Beleriand, Sindarin Tehtar, Quenya, and Black Speech. ...Visual Studio DSite: Picture Box Viewer (Visual F sharp 2008): A simple picturebox viewer made in visual f sharp 2008.Web/Cloud Applications Development Framework | Visual WebGui: 6.4 Beta 2d: Further stabilization of the cutting-edge web applications frameworkWebAssert: WebAssert 0.1: Initial release. Supports HTML & CSS validation using MSTest/Visual Studio testing.XAML Based Chat: Test release: A test releaseすとれおじさん(仮): すとれおじさん β 0.02: ・デザインを大幅に変更 ・まだかなり動作が重いです ・機能も少ないですMost Popular ProjectsRawrWBFS ManagerSilverlight ToolkitAJAX Control ToolkitMicrosoft SQL Server Product Samples: Databasepatterns & practices – Enterprise LibraryWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesPHPExcelMost Active Projectspatterns & practices – Enterprise LibraryRawrParticle Plot PivotBlogEngine.NETNB_Store - Free DotNetNuke Ecommerce Catalog ModuleGMap.NET - Great Maps for Windows Forms & PresentationFarseer Physics EngineDotNetZip LibraryFluent Ribbon Control SuiteN2 CMS

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• How I understood monads, part 1/2: sleepless and self-loathing in Seattle

  For some time now, I had been noticing some interest for monads, mostly in the form of unintelligible (to me) blog posts and comments saying oh, yeah, thats a monad about random stuff as if it were absolutely obvious and if I didnt know what they were talking about, I was probably an uneducated idiot, ignorant about the simplest and most fundamental concepts of functional programming. Fair enough, I am pretty much exactly that. Being the kind of guy who can spend eight years in college just to...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• C#/.NET Little Wonders: Fun With Enum Methods

  - by James Michael Hare

  Once again lets dive into the Little Wonders of .NET, those small things in the .NET languages and BCL classes that make development easier by increasing readability, maintainability, and/or performance. So probably every one of us has used an enumerated type at one time or another in a C# program.  The enumerated types we create are a great way to represent that a value can be one of a set of discrete values (or a combination of those values in the case of bit flags). But the power of enum types go far beyond simple assignment and comparison, there are many methods in the Enum class (that all enum types “inherit” from) that can give you even more power when dealing with them. IsDefined() – check if a given value exists in the enum Are you reading a value for an enum from a data source, but are unsure if it is actually a valid value or not?  Casting won’t tell you this, and Parse() isn’t guaranteed to balk either if you give it an int or a combination of flags.  So what can we do? Let’s assume we have a small enum like this for result codes we want to return back from our business logic layer: 1: public enum ResultCode 2: { 3: Success, 4: Warning, 5: Error 6: } In this enum, Success will be zero (unless given another value explicitly), Warning will be one, and Error will be two. So what happens if we have code like this where perhaps we’re getting the result code from another data source (could be database, could be web service, etc)? 1: public ResultCode PerformAction() 2: { 3: // set up and call some method that returns an int. 4: int result = ResultCodeFromDataSource(); 5:  6: // this will suceed even if result is < 0 or > 2. 7: return (ResultCode) result; 8: } So what happens if result is –1 or 4?  Well, the cast does not fail, so what we end up with would be an instance of a ResultCode that would have a value that’s outside of the bounds of the enum constants we defined. This means if you had a block of code like: 1: switch (result) 2: { 3: case ResultType.Success: 4: // do success stuff 5: break; 6:  7: case ResultType.Warning: 8: // do warning stuff 9: break; 10:  11: case ResultType.Error: 12: // do error stuff 13: break; 14: } That you would hit none of these blocks (which is a good argument for always having a default in a switch by the way). So what can you do?  Well, there is a handy static method called IsDefined() on the Enum class which will tell you if an enum value is defined.  1: public ResultCode PerformAction() 2: { 3: int result = ResultCodeFromDataSource(); 4:  5: if (!Enum.IsDefined(typeof(ResultCode), result)) 6: { 7: throw new InvalidOperationException("Enum out of range."); 8: } 9:  10: return (ResultCode) result; 11: } In fact, this is often recommended after you Parse() or cast a value to an enum as there are ways for values to get past these methods that may not be defined. If you don’t like the syntax of passing in the type of the enum, you could clean it up a bit by creating an extension method instead that would allow you to call IsDefined() off any isntance of the enum: 1: public static class EnumExtensions 2: { 3: // helper method that tells you if an enum value is defined for it's enumeration 4: public static bool IsDefined(this Enum value) 5: { 6: return Enum.IsDefined(value.GetType(), value); 7: } 8: }   HasFlag() – an easier way to see if a bit (or bits) are set Most of us who came from the land of C programming have had to deal extensively with bit flags many times in our lives.  As such, using bit flags may be almost second nature (for a quick refresher on bit flags in enum types see one of my old posts here). However, in higher-level languages like C#, the need to manipulate individual bit flags is somewhat diminished, and the code to check for bit flag enum values may be obvious to an advanced developer but cryptic to a novice developer. For example, let’s say you have an enum for a messaging platform that contains bit flags: 1: // usually, we pluralize flags enum type names 2: [Flags] 3: public enum MessagingOptions 4: { 5: None = 0, 6: Buffered = 0x01, 7: Persistent = 0x02, 8: Durable = 0x04, 9: Broadcast = 0x08 10: } We can combine these bit flags using the bitwise OR operator (the ‘|’ pipe character): 1: // combine bit flags using 2: var myMessenger = new Messenger(MessagingOptions.Buffered | MessagingOptions.Broadcast); Now, if we wanted to check the flags, we’d have to test then using the bit-wise AND operator (the ‘&’ character): 1: if ((options & MessagingOptions.Buffered) == MessagingOptions.Buffered) 2: { 3: // do code to set up buffering... 4: // ... 5: } While the ‘|’ for combining flags is easy enough to read for advanced developers, the ‘&’ test tends to be easy for novice developers to get wrong.  First of all you have to AND the flag combination with the value, and then typically you should test against the flag combination itself (and not just for a non-zero)!  This is because the flag combination you are testing with may combine multiple bits, in which case if only one bit is set, the result will be non-zero but not necessarily all desired bits! Thanks goodness in .NET 4.0 they gave us the HasFlag() method.  This method can be called from an enum instance to test to see if a flag is set, and best of all you can avoid writing the bit wise logic yourself.  Not to mention it will be more readable to a novice developer as well: 1: if (options.HasFlag(MessagingOptions.Buffered)) 2: { 3: // do code to set up buffering... 4: // ... 5: } It is much more concise and unambiguous, thus increasing your maintainability and readability. It would be nice to have a corresponding SetFlag() method, but unfortunately generic types don’t allow you to specialize on Enum, which makes it a bit more difficult.  It can be done but you have to do some conversions to numeric and then back to the enum which makes it less of a payoff than having the HasFlag() method.  But if you want to create it for symmetry, it would look something like this: 1: public static T SetFlag<T>(this Enum value, T flags) 2: { 3: if (!value.GetType().IsEquivalentTo(typeof(T))) 4: { 5: throw new ArgumentException("Enum value and flags types don't match."); 6: } 7:  8: // yes this is ugly, but unfortunately we need to use an intermediate boxing cast 9: return (T)Enum.ToObject(typeof (T), Convert.ToUInt64(value) | Convert.ToUInt64(flags)); 10: } Note that since the enum types are value types, we need to assign the result to something (much like string.Trim()).  Also, you could chain several SetFlag() operations together or create one that takes a variable arg list if desired. Parse() and ToString() – transitioning from string to enum and back Sometimes, you may want to be able to parse an enum from a string or convert it to a string - Enum has methods built in to let you do this.  Now, many may already know this, but may not appreciate how much power are in these two methods. For example, if you want to parse a string as an enum, it’s easy and works just like you’d expect from the numeric types: 1: string optionsString = "Persistent"; 2:  3: // can use Enum.Parse, which throws if finds something it doesn't like... 4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result == MessagingOptions.Persistent) 7: { 8: Console.WriteLine("It worked!"); 9: } Note that Enum.Parse() will throw if it finds a value it doesn’t like.  But the values it likes are fairly flexible!  You can pass in a single value, or a comma separated list of values for flags and it will parse them all and set all bits: 1: // for string values, can have one, or comma separated. 2: string optionsString = "Persistent, Buffered"; 3:  4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked!"); 9: } Or you can parse in a string containing a number that represents a single value or combination of values to set: 1: // 3 is the combination of Buffered (0x01) and Persistent (0x02) 2: var optionsString = "3"; 3:  4: var result = (MessagingOptions) Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked again!"); 9: } And, if you really aren’t sure if the parse will work, and don’t want to handle an exception, you can use TryParse() instead: 1: string optionsString = "Persistent, Buffered"; 2: MessagingOptions result; 3:  4: // try parse returns true if successful, and takes an out parm for the result 5: if (Enum.TryParse(optionsString, out result)) 6: { 7: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 8: { 9: Console.WriteLine("It worked!"); 10: } 11: } So we covered parsing a string to an enum, what about reversing that and converting an enum to a string?  The ToString() method is the obvious and most basic choice for most of us, but did you know you can pass a format string for enum types that dictate how they are written as a string?: 1: MessagingOptions value = MessagingOptions.Buffered | MessagingOptions.Persistent; 2:  3: // general format, which is the default, 4: Console.WriteLine("Default : " + value); 5: Console.WriteLine("G (default): " + value.ToString("G")); 6:  7: // Flags format, even if type does not have Flags attribute. 8: Console.WriteLine("F (flags) : " + value.ToString("F")); 9:  10: // integer format, value as number. 11: Console.WriteLine("D (num) : " + value.ToString("D")); 12:  13: // hex format, value as hex 14: Console.WriteLine("X (hex) : " + value.ToString("X")); Which displays: 1: Default : Buffered, Persistent 2: G (default): Buffered, Persistent 3: F (flags) : Buffered, Persistent 4: D (num) : 3 5: X (hex) : 00000003 Now, you may not really see a difference here between G and F because I used a [Flags] enum, the difference is that the “F” option treats the enum as if it were flags even if the [Flags] attribute is not present.  Let’s take a non-flags enum like the ResultCode used earlier: 1: // yes, we can do this even if it is not [Flags] enum. 2: ResultCode value = ResultCode.Warning | ResultCode.Error; And if we run that through the same formats again we get: 1: Default : 3 2: G (default): 3 3: F (flags) : Warning, Error 4: D (num) : 3 5: X (hex) : 00000003 Notice that since we had multiple values combined, but it was not a [Flags] marked enum, the G and default format gave us a number instead of a value name.  This is because the value was not a valid single-value constant of the enum.  However, using the F flags format string, it broke out the value into its component flags even though it wasn’t marked [Flags]. So, if you want to get an enum to display appropriately for whether or not it has the [Flags] attribute, use G which is the default.  If you always want it to attempt to break down the flags, use F.  For numeric output, obviously D or  X are the best choice depending on whether you want decimal or hex. Summary Hopefully, you learned a couple of new tricks with using the Enum class today!  I’ll add more little wonders as I think of them and thanks for all the invaluable input!   Technorati Tags: C#,.NET,Little Wonders,Enum,BlackRabbitCoder

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• HTG Explains: What’s the Difference Between CC and BCC When Sending an Email?

  - by Chris Hoffman

  The CC and BCC fields when sending email work similarly. CC stands for “carbon copy,” while BCC stands for “blind carbon copy.” While these terms may have been immediately obvious when email was invented, they’re antiquated today. CC and BCC are both ways of sending copies of an email to additional people. However, you can also send copies of an email to additional people by specifying multiple addresses in the To field. How To Play DVDs on Windows 8 6 Start Menu Replacements for Windows 8 What Is the Purpose of the “Do Not Cover This Hole” Hole on Hard Drives?

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• C++ Game Library for SVG Based Game

  - by lefticus

  I'm looking into building a cross-platform opensource 2D RPG style game engine for ChaiScript. I want to be able to do all of the graphics with SVG and need joystick input. I also need the libraries I use to be opensource and compatible with the BSD license. I'm familiar with allegro, ClanLib, and SDL. As far as I can tell, none of these libraries have built in or obvious integration for SVG. Also, I'm aware of the previous conversations on this site regarding Qt for SVG game development. I'm hoping to avoid Qt because of the size and complexity of making it a requirement. Also, Qt does not seem to have joystick input support, which would require that SDL or some other library also be used. So my question can be summed up as this: What is the best way to get SVG and joystick support in a 2D C++ library while minimizing dependencies as much as possible (preferably avoiding Qt altogether)?

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