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• Amazon EC2 root defaults on EBS

  - by CodeShining

  I'm trying to understand why when launching a new instance Amazon defaults to EBS (8gb root) instead of instance storage. Why do they sell instance storage then if it's not used also to boot the base system? Is it safe to uncheck delete on termination, make it bigger (~50GiB) and keep all files on that EBS instead of creating a new one to make sure data will persist and it will also be usable by another instance?

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• Using Reflection.Emit to match existing constructor

  - by yodaj007

  First, here is the C# code and the disassembled IL: public class Program<T> { private List<T> _items; public Program(T x, [Microsoft.Scripting.ParamDictionary] Microsoft.Scripting.IAttributesCollection col) { _items = new List<T>(); _items.Add(x); } } Here is the IL of that constructor: .method public hidebysig specialname rtspecialname instance void .ctor(!T x, class [Microsoft.Scripting]Microsoft.Scripting.IAttributesCollection col) cil managed { .param [2] .custom instance void [Microsoft.Scripting]Microsoft.Scripting.ParamDictionaryAttribute::.ctor() = ( 01 00 00 00 ) // Code size 34 (0x22) .maxstack 8 IL_0000: ldarg.0 IL_0001: call instance void [mscorlib]System.Object::.ctor() IL_0006: nop IL_0007: nop IL_0008: ldarg.0 IL_0009: newobj instance void class [mscorlib]System.Collections.Generic.List`1<!T>::.ctor() IL_000e: stfld class [mscorlib]System.Collections.Generic.List`1<!0> class Foo.Program`1<!T>::_items IL_0013: ldarg.0 IL_0014: ldfld class [mscorlib]System.Collections.Generic.List`1<!0> class Foo.Program`1<!T>::_items IL_0019: ldarg.1 IL_001a: callvirt instance void class [mscorlib]System.Collections.Generic.List`1<!T>::Add(!0) IL_001f: nop IL_0020: nop IL_0021: ret } // end of method Program`1::.ctor I am trying to understand the IL code by emitting it myself. This is what I have managed to emit: .method public hidebysig specialname rtspecialname instance void .ctor(!T A_1, class [Microsoft.Scripting]Microsoft.Scripting.IAttributesCollection A_2) cil managed { // Code size 34 (0x22) .maxstack 4 IL_0000: ldarg.0 IL_0001: call instance void [mscorlib]System.Object::.ctor() IL_0006: ldarg.0 IL_0007: newobj instance void class [mscorlib]System.Collections.Generic.List`1<!T>::.ctor() IL_000c: stfld class [mscorlib]System.Collections.Generic.List`1<!0> class MyType<!T>::_items IL_0011: ldarg.0 IL_0012: ldfld class [mscorlib]System.Collections.Generic.List`1<!0> class MyType<!T>::_items IL_0017: ldarg.s A_1 IL_0019: nop IL_001a: nop IL_001b: nop IL_001c: callvirt instance void class [mscorlib]System.Collections.Generic.List`1<!T>::Add(!0) IL_0021: ret } // end of method MyType::.ctor There are a few differences that I just can't figure out. I'm really close... How do I take care of the parameter attribute (ParamDictionaryAttribute)? I can't find a 'custom' opcode. Is the .param [2] important? How do I emit that? Why is the C# code stack size 8, while my emitted version is 4? Is this important?

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• Receive MMS images and make album using iamge using j2me

  - by Abdul Basit

  I am trying to made application which receive MMS images and make a album from them user can view the pictures while running this application. I am facing problem while running application on mobile. while this application is fully working in wireless tookit emulator. Please guide me to fix this problem.`//package hello; import javax.microedition.midlet.; import javax.microedition.lcdui.; import javax.wireless.messaging.*; import java.io.IOException; import java.util.Vector; import javax.microedition.io.Connector; import javax.microedition.lcdui.Display; //, ItemStateListener public class MMSS extends MIDlet implements CommandListener, Runnable, MessageListener { //-----------------------------------Receive MMS --------------------------- private Thread mReceiver = null; private boolean mEndNow = false; private Message msg = null; String msgReceived = null; private Image[] receivedImage = new Image[5]; private Command mExitCommand = new Command("Exit", Command.EXIT, 2); private Command mRedCommand = new Command("Back", Command.SCREEN, 1); private Command mBlueCommand = new Command("Next", Command.SCREEN, 1); private Command mPlay = new Command("Play", Command.SCREEN, 1); protected static final String DEFAULT_IMAGE = "/MMSS_logo.jpg"; //protected static final String DEFAULT_IMAGE = "/wait.png"; private Display mDisplay = null; //protected ImageItem mColorSquare = null; protected Image mInitialImage = null; private String mAppID = "MMSMIDlet"; private TextField imageName = null; //private Form mForm = null; private int count = 0; private int next = 0; private Integer mMonitor = new Integer(0); //----------------------------------- End Receive MMS --------------------------- private boolean midletPaused = false; private Command exitCommand; private Command exitCommand1; private Command backCommand; private Form form; private StringItem stringItem; private ImageItem imageItem; private Image image1; private Alert alert; private List locationList; private Alert cannotAddLocationAlert; public MMSS() { } /** * Initilizes the application. * It is called only once when the MIDlet is started. The method is called before the startMIDlet method. */ private void initialize() { } /** * Performs an action assigned to the Mobile Device - MIDlet Started point. */ public void startMIDlet() { // write pre-action user code here switchDisplayable(null, getForm()); // write post-action user code here } /** * Performs an action assigned to the Mobile Device - MIDlet Resumed point. */ public void resumeMIDlet() { } /** * Switches a current displayable in a display. The display instance is taken from getDisplay method. This method is used by all actions in the design for switching displayable. * @param alert the Alert which is temporarily set to the display; if null, then nextDisplayable is set immediately * @param nextDisplayable the Displayable to be set / public void switchDisplayable(Alert alert, Displayable nextDisplayable) {//GEN-END:|5-switchDisplayable|0|5-preSwitch // write pre-switch user code here Display display = getDisplay();//GEN-BEGIN:|5-switchDisplayable|1|5-postSwitch if (alert == null) { display.setCurrent(nextDisplayable); } else { display.setCurrent(alert, nextDisplayable); } } /* * Called by a system to indicated that a command has been invoked on a particular displayable. * @param command the Command that was invoked * @param displayable the Displayable where the command was invoked */ public void commandAction(Command command, Displayable displayable) { // write pre-action user code here if (displayable == form) { if (command == exitCommand) { // write pre-action user code here exitMIDlet(); // write post-action user code here } } // write post-action user code here } /** * Returns an initiliazed instance of exitCommand component. * @return the initialized component instance */ public Command getExitCommand() { if (exitCommand == null) { // write pre-init user code here exitCommand = new Command("Exit", Command.EXIT, 0); // write post-init user code here } return exitCommand; } /** * Returns an initiliazed instance of form component. * @return the initialized component instance */ public Form getForm() { if (form == null) { // write pre-init user code here form = new Form("Welcome to MMSS", new Item[] { getStringItem(), getImageItem() }); form.addCommand(getExitCommand()); form.setCommandListener(this); // write post-init user code here } return form; } /** * Returns an initiliazed instance of stringItem component. * @return the initialized component instance */ public StringItem getStringItem() { if (stringItem == null) { // write pre-init user code here stringItem = new StringItem("Hello", "Hello, World!"); // write post-init user code here } return stringItem; } /** * Returns an initiliazed instance of exitCommand1 component. * @return the initialized component instance / public Command getExitCommand1() { if (exitCommand1 == null) { // write pre-init user code here exitCommand1 = new Command("Exit", Command.EXIT, 0); // write post-init user code here } return exitCommand1; } /* * Returns an initiliazed instance of imageItem component. * @return the initialized component instance */ public ImageItem getImageItem() { if (imageItem == null) { // write pre-init user code here imageItem = new ImageItem("imageItem", getImage1(), ImageItem.LAYOUT_CENTER | Item.LAYOUT_TOP | Item.LAYOUT_BOTTOM | Item.LAYOUT_VCENTER | Item.LAYOUT_EXPAND | Item.LAYOUT_VEXPAND, "");//GEN-LINE:|26-getter|1|26-postInit // write post-init user code here } return imageItem; } /** * Returns an initiliazed instance of image1 component. * @return the initialized component instance */ public Image getImage1() { if (image1 == null) { // write pre-init user code here try { image1 = Image.createImage("/B.jpg"); } catch (java.io.IOException e) { e.printStackTrace(); } // write post-init user code here } return image1; } /** * Returns a display instance. * @return the display instance. */ public Display getDisplay () { return Display.getDisplay(this); } /** * Exits MIDlet. */ public void exitMIDlet() { switchDisplayable (null, null); destroyApp(true); notifyDestroyed(); } /** * Called when MIDlet is started. * Checks whether the MIDlet have been already started and initialize/starts or resumes the MIDlet. */ public void startApp() { if (midletPaused) { resumeMIDlet (); } else { initialize (); startMIDlet (); } midletPaused = false; /////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////// try { conn = (MessageConnection) Connector.open("mms://:" + mAppID); conn.setMessageListener(this); } catch (Exception e) { System.out.println("startApp caught: "); e.printStackTrace(); } if (conn != null) { startReceive(); } /////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////// } /** * Called when MIDlet is paused. */ public void pauseApp() { midletPaused = true; mEndNow = true; try { conn.setMessageListener(null); conn.close(); } catch (IOException ex) { System.out.println("pausetApp caught: "); ex.printStackTrace(); } } /** * Called to signal the MIDlet to terminate. * @param unconditional if true, then the MIDlet has to be unconditionally terminated and all resources has to be released. */ public void destroyApp(boolean unconditional) { mEndNow = true; try { conn.close(); } catch (IOException ex) { System.out.println("destroyApp caught: "); ex.printStackTrace(); } } private void startReceive() { mEndNow = false; //---- Start receive thread mReceiver = new Thread(this); mReceiver.start(); } protected MessageConnection conn = null; protected int mMsgAvail = 0; // -------------------- Get Next Images ------------------------------------ private void getMessage() { synchronized(mMonitor) { mMsgAvail++; mMonitor.notify(); } } // -------------------- Display Images Thread ------------------------------ public void notifyIncomingMessage(MessageConnection msgConn) { if (msgConn == conn) getMessage(); } public void itemStateChanged(Item item) { throw new UnsupportedOperationException("Not supported yet."); } class SetImage implements Runnable { private Image img = null; public SetImage(Image inImg) { img = inImg; } public void run() { imageItem.setImage(img); imageName.setString(Integer.toString(count)); } } public void run() { mMsgAvail = 0; while (!mEndNow) { synchronized(mMonitor) { // Enter monitor if (mMsgAvail <= 0) try { mMonitor.wait(); } catch (InterruptedException ex) { } mMsgAvail--; } try { msg = conn.receive(); if (msg instanceof MultipartMessage) { MultipartMessage mpm = (MultipartMessage)msg; MessagePart[] parts = mpm.getMessageParts(); if (parts != null) { for (int i = 0; i < parts.length; i++) { MessagePart mp = parts[i]; byte[] ba = mp.getContent(); receivedImage[count] = Image.createImage(ba, 0, ba.length); } Display.getDisplay(this).callSerially(new SetImage(receivedImage[count])); } } } catch (IOException e) { System.out.println("Receive thread caught: "); e.printStackTrace(); } count++; } // of while } } `

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• Problems with classes (super new)

  - by user260036

  Hi, I've problems to figure it out what's happening in the following exercise, I'm learning Smalltalk, so I'm newbie. Class Anew ^super new initialize. Ainitialize a:=0. Class Bnew: aParameter |instance| instance := super new. instance b: instance a + aParameter. ^instance Binitialize b:=0. The problem says what happen when the following code is executed: B new:10. But I can't not figure it out why instance variable does not belong to A class. Thanks

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• some confusions to singleton pattern in PHP

  - by SpawnCxy

  Hi all, In my team I've been told to write resource class like this style: class MemcacheService { private static $instance = null; private function __construct() { } public static function getInstance($fortest = false) { if (self::$instance == null) { self::$instance = new Memcached(); if ($fortest) { self::$instance->addServer(MEMTEST_HOST, MEMTEST_PORT); } else { self::$instance->addServer(MEM_HOST, MEM_PORT); } } return self::$instance; } } But I think in PHP resource handles will be released and initialized again every time after a request over. That means MemcacheService::getInstance() is totally equal new Memcached() which cannot be called singleton pattern at all. Please correct me if I'm wrong. Regards

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• XForms: set default selection in dropdown in binding

  - by Purni

  I have a main instance named 'myinstance' which has the element . Color can be 'Red', 'Blue', 'Green' or ''Yellow'. The colors are populated in a drop-down from another instance called 'colorsinstance'. When my form loads, I want the default in the dropdown to be set to 'Green' in the nodeset binding. <instance id="colorsinstance"> <items> <item label="Color1" value="Red"/> <item label="Color2" value="Blue"/> <item label="Color3" value="Green"/> <item label="Color4" value="Yellow"/> </items> </instance> Main instance binding is as follows: <xforms:bind nodeset="instance('myinstance')"> <xforms:bind nodeset="./color" required="true()"/> </xforms:bind>

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• How do I remove duplicate SQL Server 2008 instances after upgrading from SQL Server 2005?

  - by andypike

  I've just upgraded an existing SQL Server 2005 to 2008 by running the installer (not the platform installer). It all seems to have worked - there were no errors reported and my code that connects to these databases still works fine. The problem is, when I try installing SQL Server Management Studio Express 2008 I am shown then following error message when I select to add new features to an existing instance of SQL Server 2008: The SQL Server instance 'SQL1MINUS102' already has an Instance ID '2' that is different than the specified Instance ID 'SQL1MINUS102'. Specifying more than one instance ID for the same SQL Server instance is not supported. Here is a screenshot of the installation dialog and the setup discovery report: Screenshot Notice that there are two instances with the same name. So any ideas how I should recifiy this so that I can install Management studio? Thanks in advance

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• Amazon EC2 spot instances - is there a catch ?

  - by gareth_bowles

  I needed to start a new EC2 instance today and decided to try out the new spot instances, where you can reduce your instance cost by bidding on the maximum per-hour price you're prepared to pay. Since today's spot price was only 35c / hour, compared with 85c / hour for an on-demand instance, I was wondering: if I just bid a really high price, say $1 / hour, can I effectively be sure of getting a much cheaper long-running instance than an on-demand instance (since the spot instances are only charged by the current spot price) ? I suppose it's theoretically possible for the spot price to go over the on-demand price, but as far as I can tell from the data on the AWS site, the spot price has always been well below that.

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• Amazon EC2 spot instances - is there a catch ?

  - by gareth_bowles

  I needed to start a new EC2 instance today and decided to try out the new spot instances, where you can reduce your instance cost by bidding on the maximum per-hour price you're prepared to pay. Since today's spot price was only 3.5c / hour, compared with 8.5c / hour for an on-demand instance, I was wondering: if I just bid a really high price, say 10c / hour, can I effectively be sure of getting a much cheaper long-running instance than an on-demand instance (since the spot instances are only charged by the current spot price) ? I suppose it's theoretically possible for the spot price to go over the on-demand price, but as far as I can tell from the data on the AWS site, the spot price has always been well below that.

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• Communication Between Your PC and Azure VM via Windows Azure Connect

  - by Shaun

  With the new release of the Windows Azure platform there are a lot of new features available. In my previous post I introduced a little bit about one of them, the remote desktop access to azure virtual machine. Now I would like to talk about another cool stuff – Windows Azure Connect.   What’s Windows Azure Connect I would like to quote the definition of the Windows Azure Connect in MSDN With Windows Azure Connect, you can use a simple user interface to configure IP-sec protected connections between computers or virtual machines (VMs) in your organization’s network, and roles running in Windows Azure. IP-sec protects communications over Internet Protocol (IP) networks through the use of cryptographic security services. There’s an image available at the MSDN as well that I would like to forward here As we can see, using the Windows Azure Connect the Worker Role 1 and Web Role 1 are connected with the development machines and database servers which some of them are inside the organization some are not. With the Windows Azure Connect, the roles deployed on the cloud could consume the resource which located inside our Intranet or anywhere in the world. That means the roles can connect to the local database, access the local shared resource such as share files, folders and printers, etc.   Difference between Windows Azure Connect and AppFabric It seems that the Windows Azure Connect are duplicated with the Windows Azure AppFabric. Both of them are aiming to solve the problem on how to communication between the resource in the cloud and inside the local network. The table below lists the differences in my understanding. Category Windows Azure Connect Windows Azure AppFabric Purpose An IP-sec connection between the local machines and azure roles. An application service running on the cloud. Connectivity IP-sec, Domain-joint Net Tcp, Http, Https Components Windows Azure Connect Driver Service Bus, Access Control, Caching Usage Azure roles connect to local database server Azure roles use local shared files,  folders and printers, etc. Azure roles join the local AD. Expose the local service to Internet. Move the authorization process to the cloud. Integrate with existing identities such as Live ID, Google ID, etc. with existing local services. Utilize the distributed cache.   And also some scenarios on which of them should be used. Scenario Connect AppFabric I have a service deployed in the Intranet and I want the people can use it from the Internet.   Y I have a website deployed on Azure and need to use a database which deployed inside the company. And I don’t want to expose the database to the Internet. Y   I have a service deployed in the Intranet and is using AD authorization. I have a website deployed on Azure which needs to use this service. Y   I have a service deployed in the Intranet and some people on the Internet can use it but need to be authorized and authenticated.   Y I have a service in Intranet, and a website deployed on Azure. This service can be used from Internet and that website should be able to use it as well by AD authorization for more functionalities. Y Y   How to Enable Windows Azure Connect OK we talked a lot information about the Windows Azure Connect and differences with the Windows Azure AppFabric. Now let’s see how to enable and use the Windows Azure Connect. First of all, since this feature is in CTP stage we should apply before use it. On the Windows Azure Portal we can see our CTP features status under Home, Beta Program page. You can send the apply to join the Beta Programs to Microsoft in this page. After a few days the Microsoft will send an email to you (the email of your Live ID) when it’s available. In my case we can see that the Windows Azure Connect had been activated by Microsoft and then we can click the Connect button on top, or we can click the Virtual Network item from the left navigation bar.   The first thing we need, if it’s our first time to enter the Connect page, is to enable the Windows Azure Connect. After that we can see our Windows Azure Connect information in this page.   Add a Local Machine to Azure Connect As we explained below the Windows Azure Connect can make an IP-sec connection between the local machines and azure role instances. So that we firstly add a local machine into our Azure Connect. To do this we will click the Install Local Endpoint button on top and then the portal will give us an URL. Copy this URL to the machine we want to add and it will download the software to us. This software will be installed in the local machines which we want to join the Connect. After installed there will be a tray-icon appeared to indicate this machine had been joint our Connect. The local application will be refreshed to the Windows Azure Platform every 5 minutes but we can click the Refresh button to let it retrieve the latest status at once. Currently my local machine is ready for connect and we can see my machine in the Windows Azure Portal if we switched back to the portal and selected back Activated Endpoints node.   Add a Windows Azure Role to Azure Connect Let’s create a very simple azure project with a basic ASP.NET web role inside. To make it available on Windows Azure Connect we will open the azure project property of this role from the solution explorer in the Visual Studio, and select the Virtual Network tab, check the Activate Windows Azure Connect. The next step is to get the activation token from the Windows Azure Portal. In the same page there is a button named Get Activation Token. Click this button then the portal will display the token to me. We copied this token and pasted to the box in the Visual Studio tab. Then we deployed this application to azure. After completed the deployment we can see the role instance was listed in the Windows Azure Portal - Virtual Connect section.   Establish the Connect Group The final task is to create a connect group which contains the machines and role instances need to be connected each other. This can be done in the portal very easy. The machines and instances will NOT be connected until we created the group for them. The machines and instances can be used in one or more groups. In the Virtual Connect section click the Groups and Roles node from the left side navigation bar and clicked the Create Group button on top. This will bring up a dialog to us. What we need to do is to specify a group name, description; and then we need to select the local computers and azure role instances into this group. After the Azure Fabric updated the group setting we can see the groups and the endpoints in the page. And if we switch back to the local machine we can see that the tray-icon have been changed and the status turned connected. The Windows Azure Connect will update the group information every 5 minutes. If you find the status was still in Disconnected please right-click the tray-icon and select the Refresh menu to retrieve the latest group policy to make it connected.   Test the Azure Connect between the Local Machine and the Azure Role Instance Now our local machine and azure role instance had been connected. This means each of them can communication to others in IP level. For example we can open the SQL Server port so that our azure role can connect to it by using the machine name or the IP address. The Windows Azure Connect uses IPv6 to connect between the local machines and role instances. You can get the IP address from the Windows Azure Portal Virtual Network section when select an endpoint. I don’t want to take a full example for how to use the Connect but would like to have two very simple tests. The first one would be PING.   When a local machine and role instance are connected through the Windows Azure Connect we can PING any of them if we opened the ICMP protocol in the Filewall setting. To do this we need to run a command line before test. Open the command window on the local machine and the role instance, execute the command as following netsh advfirewall firewall add rule name="ICMPv6" dir=in action=allow enable=yes protocol=icmpv6 Thanks to Jason Chen, Patriek van Dorp, Anton Staykov and Steve Marx, they helped me to enable  the ICMPv6 setting. For the full discussion we made please visit here. You can use the Remote Desktop Access feature to logon the azure role instance. Please refer my previous blog post to get to know how to use the Remote Desktop Access in Windows Azure. Then we can PING the machine or the role instance by specifying its name. Below is the screen I PING my local machine from my azure instance. We can use the IPv6 address to PING each other as well. Like the image following I PING to my role instance from my local machine thought the IPv6 address.   Another example I would like to demonstrate here is folder sharing. I shared a folder in my local machine and then if we logged on the role instance we can see the folder content from the file explorer window.   Summary In this blog post I introduced about another new feature – Windows Azure Connect. With this feature our local resources and role instances (virtual machines) can be connected to each other. In this way we can make our azure application using our local stuff such as database servers, printers, etc. without expose them to Internet.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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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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• Know more about Enqueue Deadlock Detection

  - by Liu Maclean(???)

  ??? ORACLE ALLSTAR???????????????????,??????? ???????enqueue lock?????????3 ??????,????????????????????????????ora-00060 dead lock??process???3s: SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi PL/SQL Release 10.2.0.5.0 - Production CORE 10.2.0.5.0 Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com PROCESS A: set timing on; update maclean1 set t1=t1+1; PROCESS B: update maclean2 set t1=t1+1; PROCESS A: update maclean2 set t1=t1+1; PROCESS B: update maclean1 set t1=t1+1; ??3s? PROCESS A ?? ERROR at line 1: ORA-00060: deadlock detected while waiting for resource Elapsed: 00:00:03.02 ????Process A????????????? 3s,?????????????,??????? ?????????? ???????: SQL> col name for a30 SQL> col value for a5 SQL> col DESCRIB for a50 SQL> set linesize 140 pagesize 1400 SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ 2 FROM SYS.x$ksppi x, SYS.x$ksppcv y 3 WHERE x.inst_id = USERENV ('Instance') 4 AND y.inst_id = USERENV ('Instance') 5 AND x.indx = y.indx 6 AND x.ksppinm='_enqueue_deadlock_scan_secs'; NAME VALUE DESCRIB ------------------------------ ----- -------------------------------------------------- _enqueue_deadlock_scan_secs 0 deadlock scan interval SQL> alter system set "_enqueue_deadlock_scan_secs"=18 scope=spfile; System altered. Elapsed: 00:00:00.01 SQL> startup force; ORACLE instance started. Total System Global Area 851443712 bytes Fixed Size 2100040 bytes Variable Size 738198712 bytes Database Buffers 104857600 bytes Redo Buffers 6287360 bytes Database mounted. Database opened. PROCESS A: SQL> set timing on; SQL> update maclean1 set t1=t1+1; 1 row updated. Elapsed: 00:00:00.06 Process B SQL> update maclean2 set t1=t1+1; 1 row updated. SQL> update maclean1 set t1=t1+1; Process A: SQL> SQL> alter session set events '10704 trace name context forever,level 10:10046 trace name context forever,level 8'; Session altered. SQL> update maclean2 set t1=t1+1; update maclean2 set t1=t1+1 * ERROR at line 1: ORA-00060: deadlock detected while waiting for resource  Elapsed: 00:00:18.05 ksqcmi: TX,90011,4a9 mode=6 timeout=21474836 WAIT #12: nam='enq: TX - row lock contention' ela= 2930070 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114759849120 WAIT #12: nam='enq: TX - row lock contention' ela= 2930636 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114762779801 WAIT #12: nam='enq: TX - row lock contention' ela= 2930439 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114765710430 *** 2012-06-12 09:58:43.089 WAIT #12: nam='enq: TX - row lock contention' ela= 2931698 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114768642192 WAIT #12: nam='enq: TX - row lock contention' ela= 2930428 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114771572755 WAIT #12: nam='enq: TX - row lock contention' ela= 2931408 name|mode=1415053318 usn<<16 | slot=589841 sequence=1193 obj#=56810 tim=1308114774504207 DEADLOCK DETECTED ( ORA-00060 ) [Transaction Deadlock] The following deadlock is not an ORACLE error. It is a deadlock due to user error in the design of an application or from issuing incorrect ad-hoc SQL. The following information may aid in determining the deadlock: ??????Process A?’enq: TX – row lock contention’ ?????ORA-00060 deadlock detected????3s ??? 18s , ???hidden parameter “_enqueue_deadlock_scan_secs”?????,????????0? ??????????: SQL> alter system set "_enqueue_deadlock_scan_secs"=4 scope=spfile; System altered. Elapsed: 00:00:00.01 SQL> alter system set "_enqueue_deadlock_time_sec"=9 scope=spfile; System altered. Elapsed: 00:00:00.00 SQL> startup force; ORACLE instance started. Total System Global Area 851443712 bytes Fixed Size 2100040 bytes Variable Size 738198712 bytes Database Buffers 104857600 bytes Redo Buffers 6287360 bytes Database mounted. Database opened. SQL> set linesize 140 pagesize 1400 SQL> show parameter dead NAME TYPE VALUE ------------------------------------ -------------------------------- ------------------------------ _enqueue_deadlock_scan_secs integer 4 _enqueue_deadlock_time_sec integer 9 SQL> set timing on SQL> select * from maclean1 for update wait 8; T1 ---------- 11 Elapsed: 00:00:00.01 PROCESS B SQL> select * from maclean2 for update wait 8; T1 ---------- 3 SQL> select * from maclean1 for update wait 8; select * from maclean1 for update wait 8 PROCESS A SQL> select * from maclean2 for update wait 8; select * from maclean2 for update wait 8 * ERROR at line 1: ORA-30006: resource busy; acquire with WAIT timeout expired Elapsed: 00:00:08.00 ???????? ??? select for update wait?enqueue request timeout ?????8s? ,???????”_enqueue_deadlock_scan_secs”=4(deadlock scan interval),?4s???deadlock detected,????Process A????deadlock ???, ??????? ??Process A?????8s?raised??”ORA-30006: resource busy; acquire with WAIT timeout expired”??,??ORA-00060,?????process A???????? ????????”_enqueue_deadlock_time_sec”(requests with timeout <= this will not have deadlock detection)???,?enqueue request time < “_enqueue_deadlock_time_sec”?Server process?????dead lock detection,?????????enqueue request ??????timeout??????(_enqueue_deadlock_time_sec????5,?timeout<5s),???????????????;??????timeout>”_enqueue_deadlock_time_sec”???,Oracle????????????????????? ??????????: SQL> show parameter dead NAME TYPE VALUE ------------------------------------ -------------------------------- ------------------------------ _enqueue_deadlock_scan_secs integer 4 _enqueue_deadlock_time_sec integer 9 Process A: SQL> set timing on; SQL> select * from maclean1 for update wait 10; T1 ---------- 11 Process B: SQL> select * from maclean2 for update wait 10; T1 ---------- 3 SQL> select * from maclean1 for update wait 10; PROCESS A: SQL> select * from maclean2 for update wait 10; select * from maclean2 for update wait 10 * ERROR at line 1: ORA-00060: deadlock detected while waiting for resource Elapsed: 00:00:06.02 ??????? select for update wait 10?10s??, ?? 10s?????_enqueue_deadlock_time_sec???(9s),??Process A???????? ???????????????6s ???????_enqueue_deadlock_scan_secs?4s ? ???????????,???????????_enqueue_deadlock_scan_secs?????????3???? ??: enqueue lock?????????????? 1. ?????????deadlock detection??3s????, ????????_enqueue_deadlock_scan_secs(deadlock scan interval)???,??????0,????????_enqueue_deadlock_scan_secs?????????3???, ?_enqueue_deadlock_scan_secs=0 ??3s??, ?_enqueue_deadlock_scan_secs=4??6s??,????? 2. ???????_enqueue_deadlock_time_sec(requests with timeout <= this will not have deadlock detection)???,?enqueue request timeout< _enqueue_deadlock_time_sec(????5),?Server process?????????enqueue request timeout>_enqueue_deadlock_time_sec ????_enqueue_deadlock_scan_secs???????, ??request timeout??????select for update wait [TIMEOUT]??? ??: ???10.2.0.1?????????2?hidden parameter , ???patchset 10.2.0.3????? _enqueue_deadlock_time_sec, ?patchset 10.2.0.5??????_enqueue_deadlock_scan_secs? ?????RAC???????????10s, ???????_lm_dd_interval(dd time interval in seconds) ,????????8.0.6???? ???????????????,??????,  ?10g???????60s,?11g???????10s?  ???????11g??_lm_dd_interval?????????????,?????11g??LMD????????????,??????????RAC?LMD?Deadlock Detection???????CPU,???11g?Oracle????Team???LMD????????CPU????: ????????11g?LMD???????,???????11g??? UTS TRACE ????? DD???: SQL> select * from v$version; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production PL/SQL Release 11.2.0.3.0 - Production CORE 11.2.0.3.0 Production TNS for Linux: Version 11.2.0.3.0 - Production NLSRTL Version 11.2.0.3.0 - Production SQL> SQL> select * from global_name 2 ; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> alter system set "_lm_dd_interval"=20 scope=spfile; System altered. SQL> startup force; ORACLE instance started. Total System Global Area 1570009088 bytes Fixed Size 2228704 bytes Variable Size 1325403680 bytes Database Buffers 234881024 bytes Redo Buffers 7495680 bytes Database mounted. Database opened. SQL> set linesize 140 pagesize 1400 SQL> show parameter lm_dd NAME TYPE VALUE ------------------------------------ -------------------------------- ------------------------------ _lm_dd_interval integer 20 SQL> select count(*) from gv$instance; COUNT(*) ---------- 2 instance 1: SQL> oradebug setorapid 12 Oracle pid: 12, Unix process pid: 8608, image: [email protected] (LMD0) ? LMD0??? UTS TRACE??RAC???????????? SQL> oradebug event 10046 trace name context forever,level 8:10708 trace name context forever,level 103: trace[rac.*] disk high; Statement processed. Elapsed: 00:00:00.00 SQL> update maclean1 set t1=t1+1; 1 row updated. instance 2: SQL> update maclean2 set t1=t1+1; 1 row updated. SQL> update maclean1 set t1=t1+1; Instance 1: SQL> update maclean2 set t1=t1+1; update maclean2 set t1=t1+1 * ERROR at line 1: ORA-00060: deadlock detected while waiting for resource Elapsed: 00:00:20.51 LMD0???UTS TRACE 2012-06-12 22:27:00.929284 : [kjmpbmsg:process][type 22][msg 0x7fa620ac85a8][from 1][seq 8148.0][len 192] 2012-06-12 22:27:00.929346 : [kjmxmpm][type 22][seq 0.0][msg 0x7fa620ac85a8][from 1] *** 2012-06-12 22:27:00.929 * kjddind: received DDIND msg with subtype x6 * reqp->dd_master_inst_kjxmddi == 1 * kjddind: dump sgh: 2012-06-12 22:27:00.929346*: kjddind: req->timestamp [0.15], kjddt [0.13] 2012-06-12 22:27:00.929346*: >> DDmsg:KJX_DD_REMOTE,TS[0.15],Inst 1->2,ddxid[id1,id2,inst:2097153,31,1],ddlock[0x95023930,829],ddMasterInst 1 2012-06-12 22:27:00.929346*: lock [0x95023930,829], op = [mast] 2012-06-12 22:27:00.929346*: reqp->timestamp [0.15], kjddt [0.13] 2012-06-12 22:27:00.929346*: kjddind: updated local timestamp [0.15] * kjddind: case KJX_DD_REMOTE 2012-06-12 22:27:00.929346*: ADD IO NODE WFG: 0 frame pointer 2012-06-12 22:27:00.929346*: PUSH: type=res, enqueue(0xffffffff.0xffffffff)=0xbbb9af40, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: PROCESS: type=res, enqueue(0xffffffff.0xffffffff)=0xbbb9af40, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: POP: type=res, enqueue(0xffffffff.0xffffffff)=0xbbb9af40, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: kjddopr[TX 0xe000c.0x32][ext 0x5,0x0]: blocking lock 0xbbb9a800, owner 2097154 of inst 2 2012-06-12 22:27:00.929346*: PUSH: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: PROCESS: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: ADD NODE TO WFG: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: POP: type=txn, enqueue(0xffffffff.0xffffffff)=0xbbb9a800, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: kjddopt: converting lock 0xbbce92f8 on 'TX' 0x80016.0x5d4,txid [2097154,34]of inst 2 2012-06-12 22:27:00.929346*: PUSH: type=res, enqueue(0xffffffff.0xffffffff)=0xbbce92f8, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: PROCESS: type=res, enqueue(0xffffffff.0xffffffff)=0xbbce92f8, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929346*: ADD NODE TO WFG: type=res, enqueue(0xffffffff.0xffffffff)=0xbbce92f8, block=KJUSEREX, snode=1 2012-06-12 22:27:00.929855 : GSIPC:AMBUF: rcv buff 0x7fa620aa8cd8, pool rcvbuf, rqlen 1102 2012-06-12 22:27:00.929878 : GSIPC:GPBMSG: new bmsg 0x7fa620aa8d48 mb 0x7fa620aa8cd8 msg 0x7fa620aa8d68 mlen 192 dest x100 flushsz -1 2012-06-12 22:27:00.929878*: << DDmsg:KJX_DD_REMOTE,TS[0.15],Inst 2->1,ddxid[id1,id2,inst:2097153,31,1],ddlock[0x95023930,829],ddMasterInst 1 2012-06-12 22:27:00.929878*: lock [0xbbce92f8,287], op = [mast] 2012-06-12 22:27:00.929878*: ADD IO NODE WFG: 0 frame pointer 2012-06-12 22:27:00.929923 : [kjmpbmsg:compl][msg 0x7fa620ac8588][typ p][nmsgs 1][qtime 0][ptime 0] 2012-06-12 22:27:00.929947 : GSIPC:PBAT: flush start. flag 0x79 end 0 inc 4.4 2012-06-12 22:27:00.929963 : GSIPC:PBAT: send bmsg 0x7fa620aa8d48 blen 224 dest 1.0 2012-06-12 22:27:00.929979 : GSIPC:SNDQ: enq msg 0x7fa620aa8d48, type 65521 seq 8325, inst 1, receiver 0, queued 1 012-06-12 22:27:00.929979 : GSIPC:SNDQ: enq msg 0x7fa620aa8d48, type 65521 seq 8325, inst 1, receiver 0, queued 1 2012-06-12 22:27:00.929996 : GSIPC:BSEND: flushing sndq 0xb491dd28, id 0, dcx 0xbc517770, inst 1, rcvr 0 qlen 0 1 2012-06-12 22:27:00.930014 : GSIPC:BSEND: no batch1 msg 0x7fa620aa8d48 type 65521 len 224 dest (1:0) 2012-06-12 22:27:00.930088 : kjbsentscn[0x0.3f72dc][to 1] 2012-06-12 22:27:00.930144 : GSIPC:SENDM: send msg 0x7fa620aa8d48 dest x10000 seq 8325 type 65521 tkts x1 mlen xe00110 2012-06-12 22:27:00.930531 : GSIPC:KSXPCB: msg 0x7fa620aa8d48 status 30, type 65521, dest 1, rcvr 0 WAIT #0: nam='ges remote message' ela= 1372 waittime=80 loop=0 p3=74 obj#=-1 tim=1339554420931640 2012-06-12 22:27:00.931728 : GSIPC:RCVD: ksxp msg 0x7fa620af6490 sndr 1 seq 0.8149 type 65521 tkts 1 2012-06-12 22:27:00.931746 : GSIPC:RCVD: watq msg 0x7fa620af6490 sndr 1, seq 8149, type 65521, tkts 1 2012-06-12 22:27:00.931763 : GSIPC:RCVD: seq update (0.8148)->(0.8149) tp -15 fg 0x4 from 1 pbattr 0x0 2012-06-12 22:27:00.931779 : GSIPC:TKT: collect msg 0x7fa620af6490 from 1 for rcvr 0, tickets 1 2012-06-12 22:27:00.931794 : kjbrcvdscn[0x0.3f72dc][from 1][idx 2012-06-12 22:27:00.931810 : kjbrcvdscn[no bscn dd_master_inst_kjxmddi == 1 * kjddind: dump sgh: NXTIN (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 BLOCKER 0xbbb9a800 5 wq 1 cvtops x28 TX 0xe000c.0x32(ext 0x5,0x0)[20000-0002-00000022] inst 2 BLOCKED 0xbbce92f8 5 wq 2 cvtops x1 TX 0x80016.0x5d4(ext 0x2,0x0)[20000-0002-00000022] inst 2 NXTOUT (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 2012-06-12 22:27:00.932058*: kjddind: req->timestamp [0.15], kjddt [0.15] 2012-06-12 22:27:00.932058*: >> DDmsg:KJX_DD_VALIDATE,TS[0.15],Inst 1->2,ddxid[id1,id2,inst:2097153,31,1],ddlock[0x95023930,829],ddMasterInst 1 2012-06-12 22:27:00.932058*: lock [(nil),0], op = [vald_dd] 2012-06-12 22:27:00.932058*: kjddind: updated local timestamp [0.15] * kjddind: case KJX_DD_VALIDATE *** 2012-06-12 22:27:00.932 * kjddvald called: kjxmddi stuff: * cont_lockp (nil) * dd_lockp 0x95023930 * dd_inst 1 * dd_master_inst 1 * sgh graph: NXTIN (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 BLOCKER 0xbbb9a800 5 wq 1 cvtops x28 TX 0xe000c.0x32(ext 0x5,0x0)[20000-0002-00000022] inst 2 BLOCKED 0xbbce92f8 5 wq 2 cvtops x1 TX 0x80016.0x5d4(ext 0x2,0x0)[20000-0002-00000022] inst 2 NXTOUT (nil) 0 wq 0 cvtops x0 0x0.0x0(ext 0x0,0x0)[0000-0000-00000000] inst 1 POP WFG NODE: lock=(nil) * kjddvald: dump the PRQ: BLOCKER 0xbbb9a800 5 wq 1 cvtops x28 TX 0xe000c.0x32(ext 0x5,0x0)[20000-0002-00000022] inst 2 BLOCKED 0xbbce92f8 5 wq 2 cvtops x1 TX 0x80016.0x5d4(ext 0x2,0x0)[20000-0002-00000022] inst 2 * kjddvald: KJDD_NXTONOD ->node_kjddsg.dinst_kjddnd =1 * kjddvald: ... which is not my node, my subgraph is validated but the cycle is not complete Global blockers dump start:--------------------------------- DUMP LOCAL BLOCKER/HOLDER: block level 5 res [0x80016][0x5d4],[TX][ext 0x2,0x0] ??dead lock!!! ???????11.2.0.3???? RAC LMD???????????”_lm_dd_interval”????????????20s?  ???????10g?_lm_dd_interval???60s,??????Processes?????????????????,????????????Server Process????????60s??????11g?????(??????LMD???????)???????,???????????10s??? Enqueue Deadlock Detection? ?11g??? RAC?LMD???????hidden parameter ????”_lm_dd_interval”???,RAC????????????????,???????????: SQL> col name for a50 SQL> col describ for a60 SQL> col value for a20 SQL> set linesize 140 pagesize 1400 SQL> SELECT x.ksppinm NAME, y.ksppstvl VALUE, x.ksppdesc describ 2 FROM SYS.x$ksppi x, SYS.x$ksppcv y 3 WHERE x.inst_id = USERENV ('Instance') 4 AND y.inst_id = USERENV ('Instance') 5 AND x.indx = y.indx 6 AND x.ksppinm like '_lm_dd%'; NAME VALUE DESCRIB -------------------------------------------------- -------------------- ------------------------------------------------------------ _lm_dd_interval 20 dd time interval in seconds _lm_dd_scan_interval 5 dd scan interval in seconds _lm_dd_search_cnt 3 number of dd search per token get _lm_dd_max_search_time 180 max dd search time per token _lm_dd_maxdump 50 max number of locks to be dumped during dd validation _lm_dd_ignore_nodd FALSE if TRUE nodeadlockwait/nodeadlockblock options are ignored 6 rows selected.

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• Windows Azure AppFabric: ServiceBus Queue WPF Sample

  - by xamlnotes

  The latest version of the AppFabric ServiceBus now has support for queues and topics. Today I will show you a bit about using queues and also talk about some of the best practices in using them. If you are just getting started, you can check out this site for more info on Windows Azure. One of the 1st things I thought if when Azure was announced back when was how we handle fault tolerance. Web sites hosted in Azure are no much of an issue unless they are using SQL Azure and then you must account for potential fault or latency issues. Today I want to talk a bit about ServiceBus and how to handle fault tolerance.  And theres stuff like connecting to the servicebus and so on you have to take care of. To demonstrate some of the things you can do, let me walk through this sample WPF app that I am posting for you to download. To start off, the application is going to need things like the servicenamespace, issuer details and so forth to make everything work.  To facilitate this I created settings in the wpf app for all of these items. Then I mapped a static class to them and set the values when the program loads like so: StaticElements.ServiceNamespace = Convert.ToString(Properties.Settings.Default["ServiceNamespace"]); StaticElements.IssuerName = Convert.ToString(Properties.Settings.Default["IssuerName"]); StaticElements.IssuerKey = Convert.ToString(Properties.Settings.Default["IssuerKey"]); StaticElements.QueueName = Convert.ToString(Properties.Settings.Default["QueueName"]);   Now I can get to each of these elements plus some other common values or instances directly from the StaticElements class. Now, lets look at the application.  The application looks like this when it starts:   The blue graphic represents the queue we are going to use.  The next figure shows the form after items were added and the queue stats were updated . You can see how the queue has grown: To add an item to the queue, click the Add Order button which displays the following dialog: After you fill in the form and press OK, the order is published to the ServiceBus queue and the form closes. The application also allows you to read the queued items by clicking the Process Orders button. As you can see below, the form shows the queued items in a list and the  queue has disappeared as its now empty. In real practice we normally would use a Windows Service or some other automated process to subscribe to the queue and pull items from it. I created a class named ServiceBusQueueHelper that has the core queue features we need. There are three public methods: * GetOrCreateQueue – Gets an instance of the queue description if the queue exists. if not, it creates the queue and returns a description instance. * SendMessageToQueue = This method takes an order instance and sends it to the queue. The call to the queue is wrapped in the ExecuteAction method from the Transient Fault Tolerance Framework and handles all the retry logic for the queue send process. * GetOrderFromQueue – Grabs an order from the queue and returns a typed order from the queue. It also marks the message complete so the queue can remove it.   Now lets turn to the WPF window code (MainWindow.xaml.cs). The constructor contains the 4 lines shown about to setup the static variables and to perform other initialization tasks. The next few lines setup certain features we need for the ServiceBus: TokenProvider credentials = TokenProvider.CreateSharedSecretTokenProvider(StaticElements.IssuerName, StaticElements.IssuerKey); Uri serviceUri = ServiceBusEnvironment.CreateServiceUri("sb", StaticElements.ServiceNamespace, string.Empty); StaticElements.CurrentNamespaceManager = new NamespaceManager(serviceUri, credentials); StaticElements.CurrentMessagingFactory = MessagingFactory.Create(serviceUri, credentials); The next two lines update the queue name label and also set the timer to 20 seconds.             QueueNameLabel.Content = StaticElements.QueueName;             _timer.Interval = TimeSpan.FromSeconds(20);             Next I call the UpdateQueueStats to initialize the UI for the queue:             UpdateQueueStats();             _timer.Tick += new EventHandler(delegate(object s, EventArgs a)                         {                      UpdateQueueStats();                  });             _timer.Start();         } The UpdateQueueStats method shown below. You can see that it uses the GetOrCreateQueue method mentioned earlier to grab the queue description, then it can get the MessageCount property.         private void UpdateQueueStats()         {             _queueDescription = _serviceBusQueueHelper.GetOrCreateQueue();             QueueCountLabel.Content = "(" + _queueDescription.MessageCount + ")";             long count = _queueDescription.MessageCount;             long queueWidth = count * 20;             QueueRectangle.Width = queueWidth;             QueueTickCount += 1;             TickCountlabel.Content = QueueTickCount.ToString();         }   The ReadQueueItemsButton_Click event handler calls the GetOrderFromQueue method and adds the order to the listbox. If you look at the SendQueueMessageController, you can see the SendMessage method that sends an order to the queue. Its pretty simple as it just creates a new CustomerOrderEntity instance,fills it and then passes it to the SendMessageToQueue. As you can see, all of our interaction with the queue is done through the helper class (ServiceBusQueueHelper). Now lets dig into the helper class. First, before you create anything like this, download the Transient Fault Handling Framework. Microsoft provides this free and they also provide the C# source. Theres a great article that shows how to use this framework with ServiceBus. I included the entire ServiceBusQueueHelper class in List 1. Notice the using statements for TransientFaultHandling: using Microsoft.AzureCAT.Samples.TransientFaultHandling; using Microsoft.AzureCAT.Samples.TransientFaultHandling.ServiceBus; The SendMessageToQueue in Listing 1 shows how to use the async send features of ServiceBus with them wrapped in the Transient Fault Handling Framework.  It is not much different than plain old ServiceBus calls but it sure makes it easy to have the fault tolerance added almost for free. The GetOrderFromQueue uses the standard synchronous methods to access the queue. The best practices article walks through using the async approach for a receive operation also.  Notice that this method makes a call to Receive to get the message then makes a call to GetBody to get a new strongly typed instance of CustomerOrderEntity to return. Listing 1 using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.AzureCAT.Samples.TransientFaultHandling; using Microsoft.AzureCAT.Samples.TransientFaultHandling.ServiceBus; using Microsoft.ServiceBus; using Microsoft.ServiceBus.Messaging; using System.Xml.Serialization; using System.Diagnostics; namespace WPFServicebusPublishSubscribeSample {     class ServiceBusQueueHelper     {         RetryPolicy currentPolicy = new RetryPolicy<ServiceBusTransientErrorDetectionStrategy>(RetryPolicy.DefaultClientRetryCount);         QueueClient currentQueueClient;         public QueueDescription GetOrCreateQueue()         {                        QueueDescription queue = null;             bool createNew = false;             try             {                 // First, let's see if a queue with the specified name already exists.                 queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.GetQueue(StaticElements.QueueName); });                 createNew = (queue == null);             }             catch (MessagingEntityNotFoundException)             {                 // Looks like the queue does not exist. We should create a new one.                 createNew = true;             }             // If a queue with the specified name doesn't exist, it will be auto-created.             if (createNew)             {                 try                 {                     var newqueue = new QueueDescription(StaticElements.QueueName);                     queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.CreateQueue(newqueue); });                 }                 catch (MessagingEntityAlreadyExistsException)                 {                     // A queue under the same name was already created by someone else,                     // perhaps by another instance. Let's just use it.                     queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.GetQueue(StaticElements.QueueName); });                 }             }             currentQueueClient = StaticElements.CurrentMessagingFactory.CreateQueueClient(StaticElements.QueueName);             return queue;         }         public void SendMessageToQueue(CustomerOrderEntity Order)         {             BrokeredMessage msg = null;             GetOrCreateQueue();             // Use a retry policy to execute the Send action in an asynchronous and reliable fashion.             currentPolicy.ExecuteAction             (                 (cb) =>                 {                     // A new BrokeredMessage instance must be created each time we send it. Reusing the original BrokeredMessage instance may not                     // work as the state of its BodyStream cannot be guaranteed to be readable from the beginning.                     msg = new BrokeredMessage(Order);                     // Send the event asynchronously.                     currentQueueClient.BeginSend(msg, cb, null);                 },                 (ar) =>                 {                     try                     {                         // Complete the asynchronous operation.                         // This may throw an exception that will be handled internally by the retry policy.                         currentQueueClient.EndSend(ar);                     }                     finally                     {                         // Ensure that any resources allocated by a BrokeredMessage instance are released.                         if (msg != null)                         {                             msg.Dispose();                             msg = null;                         }                     }                 },                 (ex) =>                 {                     // Always dispose the BrokeredMessage instance even if the send                     // operation has completed unsuccessfully.                     if (msg != null)                     {                         msg.Dispose();                         msg = null;                     }                     // Always log exceptions.                     Trace.TraceError(ex.Message);                 }             );         }                 public CustomerOrderEntity GetOrderFromQueue()         {             CustomerOrderEntity Order = new CustomerOrderEntity();             QueueClient myQueueClient = StaticElements.CurrentMessagingFactory.CreateQueueClient(StaticElements.QueueName, ReceiveMode.PeekLock);             BrokeredMessage message;             ServiceBusQueueHelper serviceBusQueueHelper = new ServiceBusQueueHelper();             QueueDescription queueDescription;             queueDescription = serviceBusQueueHelper.GetOrCreateQueue();             if (queueDescription.MessageCount > 0)             {                 message = myQueueClient.Receive(TimeSpan.FromSeconds(90));                 if (message != null)                 {                     try                     {                         Order = message.GetBody<CustomerOrderEntity>();                         message.Complete();                     }                     catch (Exception ex)                     {                         throw ex;                     }                 }                 else                 {                     throw new Exception("Did not receive the messages");                 }             }             return Order;         }     } } I will post a link to the download demo in a separate post soon.

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• Getting a Web Resource Url in non WebForms Applications

  - by Rick Strahl

  WebResources in ASP.NET are pretty useful feature. WebResources are resources that are embedded into a .NET assembly and can be loaded from the assembly via a special resource URL. WebForms includes a method on the ClientScriptManager (Page.ClientScript) and the ScriptManager object to retrieve URLs to these resources. For example you can do: ClientScript.GetWebResourceUrl(typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); GetWebResourceUrl requires a type (which is used for the assembly lookup in which to find the resource) and the resource id to lookup. GetWebResourceUrl() then returns a nasty old long URL like this: WebResource.axd?d=-b6oWzgbpGb8uTaHDrCMv59VSmGhilZP5_T_B8anpGx7X-PmW_1eu1KoHDvox-XHqA1EEb-Tl2YAP3bBeebGN65tv-7-yAimtG4ZnoWH633pExpJor8Qp1aKbk-KQWSoNfRC7rQJHXVP4tC0reYzVw2&t=634533278261362212 While lately excessive resource usage has been frowned upon especially by MVC developers who tend to opt for content distributed as files, I still think that Web Resources have their place even in non-WebForms applications. Also if you have existing assemblies that include resources like scripts and common image links it sure would be nice to access them from non-WebForms pages like MVC views or even in plain old Razor Web Pages. Where's my Page object Dude? Unfortunately natively ASP.NET doesn't have a mechanism for retrieving WebResource Urls outside of the WebForms engine. It's a feature that's specifically baked into WebForms and that relies specifically on the Page HttpHandler implementation. Both Page.ClientScript (obviously) and ScriptManager rely on a hosting Page object in order to work and the various methods off these objects require control instances passed. The reason for this is that the script managers can inject scripts and links into Page content (think RegisterXXXX methods) and for that a Page instance is required. However, for many other methods - like GetWebResourceUrl() - that simply return resources or resource links the Page reference is really irrelevant. While there's a separate ClientScriptManager class, it's marked as sealed and doesn't have any public constructors so you can't create your own instance (without Reflection). Even if it did the internal constructor it does have requires a Page reference. No good… So, can we get access to a WebResourceUrl generically without running in a WebForms Page instance? We just have to create a Page instance ourselves and use it internally. There's nothing intrinsic about the use of the Page class in ClientScript, at least for retrieving resources and resource Urls so it's easy to create an instance of a Page for example in a static method. For our needs of retrieving ResourceUrls or even actually retrieving script resources we can use a canned, non-configured Page instance we create on our own. The following works just fine: public static string GetWebResourceUrl(Type type, string resource ) { Page page = new Page(); return page.ClientScript.GetWebResourceUrl(type, resource); } A slight optimization for this might be to cache the created Page instance. Page tends to be a pretty heavy object to create each time a URL is required so you might want to cache the instance: public class WebUtils { private static Page CachedPage { get { if (_CachedPage == null) _CachedPage = new Page(); return _CachedPage; } } private static Page _CachedPage; public static string GetWebResourceUrl(Type type, string resource) { return CachedPage.ClientScript.GetWebResourceUrl(type, resource); } } You can now use GetWebResourceUrl in a Razor page like this: <!DOCTYPE html> <html <head> <script src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.JQUERY_SCRIPT_RESOURCE)"> </script> </head> <body> <div class="errordisplay"> <img src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.WARNING_ICON_RESOURCE)" /> This is only a Test! </div> </body> </html> And voila - there you have WebResources served from a non-Page based application. WebResources may be a on the way out, but legacy apps have them embedded and for some situations, like fallback scripts and some common image resources I still like to use them. Being able to use them from non-WebForms applications should have been built into the core ASP.NETplatform IMHO, but seeing that it's not this workaround is easy enough to implement.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  MVC   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• To ref or not to ref

  - by nmarun

  So the question is what is the point of passing a reference type along with the ref keyword? I have an Employee class as below: 1: public class Employee 2: { 3: public string FirstName { get; set; } 4: public string LastName { get; set; } 5:  6: public override string ToString() 7: { 8: return string.Format("{0}-{1}", FirstName, LastName); 9: } 10: } In my calling class, I say: 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(Employee employee) 16: { 17: employee.FirstName = "Smith"; 18: employee.LastName = "Doe"; 19: } 20: }   After having a look at the code, you’ll probably say, Well, an instance of a class gets passed as a reference, so any changes to the instance inside the CallSomeMethod, actually modifies the original object. Hence the output will be ‘John-Doe’ on the first call and ‘Smith-Doe’ on the second. And you’re right: So the question is what’s the use of passing this Employee parameter as a ref? 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(ref employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(ref Employee employee) 16: { 17: employee.FirstName = "Smith"; 18: employee.LastName = "Doe"; 19: } 20: } The output is still the same: Ok, so is there really a need to pass a reference type using the ref keyword? I’ll remove the ‘ref’ keyword and make one more change to the CallSomeMethod method. 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(Employee employee) 16: { 17: employee = new Employee 18: { 19: FirstName = "Smith", 20: LastName = "John" 21: }; 22: } 23: } In line 17 you’ll see I’ve ‘new’d up the incoming Employee parameter and then set its properties to new values. The output tells me that the original instance of the Employee class does not change. Huh? But an instance of a class gets passed by reference, so why did the values not change on the original instance or how do I keep the two instances in-sync all the times? Aah, now here’s the answer. In order to keep the objects in sync, you pass them using the ‘ref’ keyword. 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(ref employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(ref Employee employee) 16: { 17: employee = new Employee 18: { 19: FirstName = "Smith", 20: LastName = "John" 21: }; 22: } 23: } Viola! Now, to prove it beyond doubt, I said, let me try with another reference type: string. 1: class Program 2: { 3: static void Main() 4: { 5: string name = "abc"; 6: Console.WriteLine(name); 7: CallSomeMethod(ref name); 8: Console.WriteLine(name); 9: } 10:  11: private static void CallSomeMethod(ref string name) 12: { 13: name = "def"; 14: } 15: } The output was as expected, first ‘abc’ and then ‘def’ - proves the 'ref' keyword works here as well. Now, what if I remove the ‘ref’ keyword? The output should still be the same as the above right, since string is a reference type? 1: class Program 2: { 3: static void Main() 4: { 5: string name = "abc"; 6: Console.WriteLine(name); 7: CallSomeMethod(name); 8: Console.WriteLine(name); 9: } 10:  11: private static void CallSomeMethod(string name) 12: { 13: name = "def"; 14: } 15: } Wrong, the output shows ‘abc’ printed twice. Wait a minute… now how could this be? This is because string is an immutable type. This means that any time you modify an instance of string, new memory address is allocated to the instance. The effect is similar to ‘new’ing up the Employee instance inside the CallSomeMethod in the absence of the ‘ref’ keyword. Verdict: ref key came to the rescue and saved the planet… again!

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• Clustering for Mere Mortals (Pt2)

  - by Geoff N. Hiten

  Planning. I could stop there and let that be the entirety post #2 in this series.  Planning is the single most important element in building a cluster and the Laptop Demo Cluster is no exception.  One of the more awkward parts of actually creating a cluster is coordinating information between Windows Clustering and SQL Clustering.  The dialog boxes show up hours apart, but still have to have matching and consistent information. Excel seems to be a good tool for tracking these settings.  My workbook has four pages: Systems, Storage, Network, and Service Accounts.  The systems page looks like this:   Name Role Software Location East Physical Cluster Node 1 Windows Server 2008 R2 Enterprise Laptop VM West Physical Cluster Node 2 Windows Server 2008 R2 Enterprise Laptop VM North Physical Cluster Node 3 (Future Reserved) Windows Server 2008 R2 Enterprise Laptop VM MicroCluster Cluster Management Interface N/A Laptop VM SQL01 High-Performance High-Security Instance SQL Server 2008 Enterprise Edition x64 SP1 Laptop VM SQL02 High-Performance Standard-Security Instance SQL Server 2008 Enterprise Edition x64 SP1 Laptop VM SQL03 Standard-Performance High-Security Instance SQL Server 2008 Enterprise Edition x64 SP1 Laptop VM Note that everything that has a computer name is listed here, whether physical or virtual. Storage looks like this: Storage Name Instance Purpose Volume Path Size (GB) LUN ID Speed Quorum MicroCluster Cluster Quorum Quorum Q: 2     SQL01Anchor SQL01 Instance Anchor SQL01Anchor L: 2     SQL02Anchor SQL02 Instance Anchor SQL02Anchor M: 2     SQL01Data1 SQL01 SQL Data SQL01Data1 L:\MountPoints\SQL01Data1 2     SQL02Data1 SQL02 SQL Data SQL02Data1 M:\MountPoints\SQL02Data1       Starting at the left is the name used in the storage array.  It is important to rename resources at each level, whether it is Storage, LUN, Volume, or disk folder.  Otherwise, troubleshooting things gets complex and difficult.  You want to be able to glance at a resource at any level and see where it comes from and what it is connected to. Networking is the same way:   System Network VLAN  IP Subnet Mask Gateway DNS1 DNS2 East Public Cluster1 10.97.230.x(DHCP) 255.255.255.0 10.97.230.1 10.97.230.1 10.97.230.1 East Heartbeat Cluster2   255.255.255.0       West Public Cluster1 10.97.230.x(DHCP) 255.255.255.0 10.97.230.1 10.97.230.1 10.97.230.1 West Heartbeat Cluster2   255.255.255.0       North Public Cluster1 10.97.230.x(DHCP) 255.255.255.0 10.97.230.1 10.97.230.1 10.97.230.1 North Heartbeat Cluster2   255.255.255.0       SQL01 Public Cluster1 10.97.230.x(DHCP) 255.255.255.0       SQL02 Public Cluster1 10.97.230.x(DHCP) 255.255.255.0       One hallmark of a poorly planned and implemented cluster is a bunch of "Local Network Connection #n" entries in the network settings page.  That lets me know that somebody didn't care about the long-term supportabaility of the cluster.  This can be critically important with Hyper-V Clusters and their high NIC counts.  Final page:   Instance Service Name Account Password Domain OU SQL01 SQL Server SVCSQL01 Baseline22 MicroAD Service Accounts SQL01 SQL Agent SVCSQL01 Baseline22 MicroAD Service Accounts SQL02 SQL Server SVC_SQL02 Baseline22 MicroAD Service Accounts SQL02 SQL Agent SVC_SQL02 Baseline22 MicroAD Service Accounts SQL03 (Future) SQL Server SVC_SQL03 Baseline22 MicroAD Service Accounts SQL03 (Future) SQL Agent SVC_SQL03 Baseline22 MicroAD Service Accounts             Installation Account           administrator            Yes.  I write down the account information.  I secure the file via NTFS, but I don't want to fumble around looking for passwords when it comes time to rebuild a node. Always fill out the workbook COMPLETELY before installing anything.  The whole point is to have everything you need at your fingertips before you begin.  The install experience is so much better and more productive with this information in place.

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• AWS: setting up auto-scale for EC2 instances

  - by Elton Stoneman

  Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2013/10/16/aws-setting-up-auto-scale-for-ec2-instances.aspxWith Amazon Web Services, there’s no direct equivalent to Azure Worker Roles – no Elastic Beanstalk-style application for .NET background workers. But you can get the auto-scale part by configuring an auto-scaling group for your EC2 instance. This is a step-by-step guide, that shows you how to create the auto-scaling configuration, which for EC2 you need to do with the command line, and then link your scaling policies to CloudWatch alarms in the Web console. I’m using queue size as my metric for CloudWatch,  which is a good fit if your background workers are pulling messages from a queue and processing them.  If the queue is getting too big, the “high” alarm will fire and spin up a new instance to share the workload. If the queue is draining down, the “low” alarm will fire and shut down one of the instances. To start with, you need to manually set up your app in an EC2 VM, for a background worker that would mean hosting your code in a Windows Service (I always use Topshelf). If you’re dual-running Azure and AWS, then you can isolate your logic in one library, with a generic entry point that has Start() and Stop()  functions, so your Worker Role and Windows Service are essentially using the same code. When you have your instance set up with the Windows Service running automatically, and you’ve tested it starts up and works properly from a reboot, shut the machine down and take an image of the VM, using Create Image (EBS AMI) from the Web Console: When that completes, you’ll have your own AMI which you can use to spin up new instances, and you’re ready to create your auto-scaling group. You need to dip into the command-line tools for this, so follow this guide to set up the AWS autoscale command line tool. Now we’re ready to go. 1. Create a launch configuration This launch configuration tells AWS what to do when a new instance needs to be spun up. You create it with the as-create-launch-config command, which looks like this: as-create-launch-config sc-xyz-launcher # name of the launch config --image-id ami-7b9e9f12 # id of the AMI you extracted from your VM --region eu-west-1 # which region the new instance gets created in --instance-type t1.micro # size of the instance to create --group quicklaunch-1 #security group for the new instance 2. Create an auto-scaling group The auto-scaling group links to the launch config, and defines the overall configuration of the collection of instances: as-create-auto-scaling-group sc-xyz-asg # auto-scaling group name --region eu-west-1 # region to create in --launch-configuration sc-xyz-launcher # name of the launch config to invoke for new instances --min-size 1 # minimum number of nodes in the group --max-size 5 # maximum number of nodes in the group --default-cooldown 300 # period to wait (in seconds) after each scaling event, before checking if another scaling event is required --availability-zones eu-west-1a eu-west-1b eu-west-1c # which availability zones you want your instances to be allocated in – multiple entries means EC@ will use any of them 3. Create a scale-up policy The policy dictates what will happen in response to a scaling event being triggered from a “high” alarm being breached. It links to the auto-scaling group; this sample results in one additional node being spun up: as-put-scaling-policy scale-up-policy # policy name -g sc-psod-woker-asg # auto-scaling group the policy works with --adjustment 1 # size of the adjustment --region eu-west-1 # region --type ChangeInCapacity # type of adjustment, this specifies a fixed number of nodes, but you can use PercentChangeInCapacity to make an adjustment relative to the current number of nodes, e.g. increasing by 50% 4. Create a scale-down policy The policy dictates what will happen in response to a scaling event being triggered from a “low” alarm being breached. It links to the auto-scaling group; this sample results in one node from the group being taken offline: as-put-scaling-policy scale-down-policy -g sc-psod-woker-asg "--adjustment=-1" # in Windows, use double-quotes to surround a negative adjustment value –-type ChangeInCapacity --region eu-west-1 5. Create a “high” CloudWatch alarm We’re done with the command line now. In the Web Console, open up the CloudWatch view and create a new alarm. This alarm will monitor your metrics and invoke the scale-up policy from your auto-scaling group, when the group is working too hard. Configure your metric – this example will fire the alarm if there are more than 10 messages in my queue for over a minute: Then link the alarm to the scale-up policy in your group: 6. Create a “low” CloudWatch alarm The opposite of step 4, this alarm will trigger when the instances in your group don’t have enough work to do (e.g fewer than 2 messages in the queue for 1 minute), and will invoke the scale-down policy. And that’s it. You don’t need your original VM as the auto-scale group has a minimum number of nodes connected. You can test out the scaling by flexing your CloudWatch metric – in this example, filling up a queue from a  stub publisher – and watching AWS create new nodes as required, then stopping the publisher and watch AWS kill off the spare nodes.

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• Using XNA's XML content pipeline to read arrays of objects with different subtypes

  - by Mcguirk

  Using XNA's XML content importer, is it possible to read in an array of objects with different subtypes? For instance, assume these are my class definitions: public abstract class MyBaseClass { public string MyBaseData; } public class MySubClass0 : MyBaseClass { public int MySubData0; } public class MySubClass1 : MyBaseClass { public bool MySubData1; } And this is my XML file: <XnaContent> <Asset Type="MyBaseClass[]"> <Item> <!-- I want this to be an instance of MySubClass0 --> <MyBaseData>alpha</MyBaseData> <MySubData0>314</MySubData0> </Item> <Item> <!-- I want this to be an instance of MySubClass1 --> <MyBaseData>bravo</MyBaseData> <MySubData1>true</MySubData1> </Item> </Asset> </XnaContent> How do I specify that I want the first Item to be an instance of MySubclass0 and the second Item to be an instance of MySubclass1?

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• Automatically Snapshoting AWS instances (or other back up strategy)

  - by user1172468

  I just realized that my aws instance count has risen into the double digits. I'm currently backing portions of my folders and dbs and moving them off to a backup instance. What I think I should be doing is taking a snapshot of the instances (automatically) and persisting them on S3 so I have a running 7 day collection of daily backups. There is a question asking the same thing here, however the answers don't go into depth. So the closest answer seems to be: use a cron job to snapshot the instance. So do I run the cron job on the instance itself? or do I have a micro instance to run these snapshots? Could I get an example script or the command for say a linux flavor? what software must I have installed to get this to run? Thanks.

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• SQL Server Express and VS2010 Web Application .MDF file errors

  - by nannette

  I installed SQL Server 2008 as well as SQL Server Express 2008 on my new Windows 7 development environment, along with Visual Studio 2010. I could get SQL Server 2008 to work fine, but I could not use Express .MDF databases within sample web application projects without receiving the below error: Failed to generate a user instance of SQL Server due to a failure in starting the process for the user instance. The connection will be closed. For instance, I was creating an ASP.NET Web Application. When...(read more)

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• Problem with WCF-SQL Adapter

  - by Paul Petrov

  When using WCF receive adapter with SQL binding in Polling mode please be aware of the following problem. Problem: At some regular but seemingly random intervals the application stops processing new requests, places a lock on the database and prevent other application from accessing it. Initially it looked like DTC issue, as it was distributed transaction that stalled most of the time. Symptoms: Orchestration instances in Dehydrated state, receive location not picking up new messages, exclusive locks on database tables, errors in DTC trace. Cause: Microsoft has confirmed that there is a bug in the WCF-SQL adapter. In the receive adapter binding configuration there's receiveTimeout property set to 10 minutes by default. If during this period data is not found in the table the adapter would start new thread and allocate more memory without releasing old resources. Thus if there's no new data in the table for a long time a new thread will be created in the host instance every 10 minutes until it reaches threshold (1000) and then there's no threads left for this host instance and it can't start/complete any tasks. Then this host instance won't be able to do anything. If other artifacts are hosted in the instance they will suffer consequences as well. Solution: - Set receiveTimeout to the maximum time 24.20:31:23.6470000. - Place WCF-SQL receive locations in separate host to provide its own thread pool and eliminate impact on other processes - Ensure WCF-SQL dedicated host instances are restarted at interval less or equal to receiveTimeout to flush threads and memory - Monitor performance counters Process/Thread Count/BTSNTSvc{n} for thread count trend and respond to alert if it grows by restarting host instance If you use WCF-SQL Adapter in the Notification mode then make sure to remove sqlAdapterInboundTransactionBehavior otherwise this location will exhibit the same issue. In this case though, setting receiveTimeout doesn't help and new thread will be created at default intervals (10 min) ignoring maximum setting.

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• BPM 11gR1 now available on Amazon EC2

  - by Prasen Palvankar

  BPM 11gR1 now available on Amazon EC2The new Oracle BPM 11gR1, including the latest Oracle SOA Suite 11gR1 Patchset-2 is now available as an Amazon Machine Image (AMI). This is a fully configured image which requires absolutely no installation and lets you get hands on experience with the software within minutes. This image has all the required software installed and configured and includes the following:Oracle 11g Database Standard Edition Oracle SOA Suite 11gR1 Patch-set 2Oracle BPM 11gR1Oracle Webcenter with BPM Process SpacesOracle Universal Content ManagementOracle JDeveloper with SOA and BPM pluginsNote: Use of this AMI requires acceptance of Oracle Technology Network (OTN) terms of use.To use this AMI, follow these steps: Login to your Amazon account and browse to Amazon AWS Console. If this is the first time you are using Amazon Web Services please visit https://aws.amazon.com/ec2/ for information on Amazon Elastic Cloud Computing and how to get started with Amazon EC2Make sure your security group that you will be using to launch the instance allows the following ports to be opened:22 (SSH)1521, 7001, 8001, 8888, 9001Click on AMIsChange the Viewing filters to 64-bit and enter soa-bpm in the search box. You should see the following AMI:083342568607/oracle-soa-bpm-11gr1-ps2-4.1-pubSelect the AMI and click on Launch or Spot Request. For more information on spot requests, please visit the Amazon EC2 link aboveAccept all the defaults and launch the instanceWhen the instance state changes to running, copy the assigned public host name and connect to it using either PuTTY or SSH command. For PuTTY usage, refer to this document.Once you are connected to the instance using PuTTY or SSH, you will be presented with the terms of use.Accept the terms of use to proceed. This will prompt you to set passwords for your oracle OS login as well as for VNC. Note that the instance will not be usable until you have accepted the terms of use.The instance is now ready to use. The SOA/BPM and other servers are automatically started once you accept the term of use. Initial startups can take about 5-10 minutes.If you would like to use the JDeveloper installed in the AMI, you can access it either using VNC or NX. You can get the NX client from NoMachine./home/oracle/README.txt contains all the URLs that you can use to access the Enterprise Manager, BPM Composer, BPM Workspace, Webcenter etc.

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• Advise on VMWare hardware requirements and host OS

  - by edwin.nathaniel

  Hi All, I'm a newbie developer wanting to learn a bit about Virtualization (from the IT point of view, not theoretical/academic). What I'd like to do: Prepare a machine Install VMWare or VirtualBox Prepare 3 Guest OSes (one for Win2k8 server, 2 for Ubuntu Server) Win2k8 will run SQL Server 2k8 and IIS (for ASP.NET MVC deployment) 1 Ubuntu Server for Drupal, SugarCRM, MediaWiki, typical LAMP stuff 1 Ubuntu Server for Java (Tomcat/Jetty + MySQL/PostgreSQL) What I'd like to know: What would be the ideal Host OS such that the Host OS should not spend too many resources on itself but should boost these instances of VMs (e.g: does Win2k8 performs better vs Linux?) What would be the ideal machine for this (preferably AMD base chip) I'm not expecting the best performance out of this setup, just a decent one to host one drupal instance, one ASP.NET MVC (future, not now), and one Tomcat/Jetty instance. NB: If you have a better suggestions on the setup, feel free to let me know (e.g: maybe Drupal and Tomcat can be in one instance but move the database to another instance instead of 1 instance map to 1 webserver and 1 dbserver). Thank you.

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• What are the alternatives to "overriding a method" when using composition instead of inheritance?

  - by Sebastien Diot

  If we should favor composition over inheritance, the data part of it is clear, at least for me. What I don't have a clear solution to is how overwriting methods, or simply implementing them if they are defined in a pure virtual form, should be implemented. An obvious way is to wrap the instance representing the base-class into the instance representing the sub-class. But the major downsides of this are that if you have say 10 methods, and you want to override a single one, you still have to delegate every other methods anyway. And if there were several layers of inheritance, you have now several layers of wrapping, which becomes less and less efficient. Also, this only solve the problem of the object "client"; when another object calls the top wrapper, things happen like in inheritance. But when a method of the deepest instance, the base class, calls it's own methods that have been wrapped and modified, the wrapping has no effect: the call is performed by it's own method, instead of by the highest wrapper. One extreme alternative that would solve those problems would be to have one instance per method. You only wrap methods that you want to overwrite, so there is no pointless delegation. But now you end up with an incredible amount of classes and object instance, which will have a negative effect on memory usage, and this will require a lot more coding too. So, are there alternatives (preferably alternatives that can be used in Java), that: Do not result in many levels of pointless delegation without any changes. Make sure that not only the client of an object, but also all the code of the object itself, is aware of which implementation of method should be called. Does not result in an explosion of classes and instances. Ideally puts the extra memory overhead that is required at the "class"/"particular composition" level (static if you will), rather than having every object pay the memory overhead of composition. My feeling tells me that the instance representing the base class should be at the "top" of the stack/layers so it receives calls directly, and can process them directly too if they are not overwritten. But I don't know how to do it that way.

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• apache2 is making my amazon ec2 unavailable, any ideas?

  - by Tim

  I have a web server running on a EC2 c1.medium intance. The instance is running on ubuntu, with apache2 and mysql.The ubuntu and apache version are the next; Ubuntu DISTRIB_ID=Ubuntu DISTRIB_RELEASE=11.04 DISTRIB_CODENAME=natty DISTRIB_DESCRIPTION="Ubuntu 11.04" Apache2 Server version: Apache/2.2.17 (Ubuntu) Server built: Feb 22 2011 18:33:02 Sometimes randomly, my server "hangs up", I cannot connect to it using normal web access or ssh access. If I reboot the instance it reboots fine, the amazon system log doesn't show anything weird, but the problem persists The only way to solve it its stopping the instance, and start it again. I think that the problem its has something to do with apache, because the last lines of the error log lists: normal errors [Sun Jun 19 06:25:09 2011] [notice] Apache/2.2.17 (Ubuntu) PHP/5.3.5-1ubuntu7.2 with Suhosin-Patch configured -- resuming normal operations nobody cant connetc... no more erros until i stop and start the instance normal errors [Wed Jun 22 14:21:18 2011] [notice] Apache/2.2.17 (Ubuntu) PHP/5.3.5-1ubuntu7.2 with Suhosin-Patch configured -- resuming normal operations nobody cant connetc... no more erros until i stop and start the instance Can somebody please help me?

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