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  • Problem Implementing StructureMap in VB.Net Conversion of SharpArchitecture

    - by Monkeeman69
    I work in a VB.Net environment and have recently been tasked with creating an MVC enviroment to use as a base to work from. I decided to convert the latest SharpArchitecture release (Q3 2009) into VB, which on the whole has gone fine after a bit of hair pulling. I came across a problem with Castle Windsor where my custom repository interface (lives in the core/domain project) that was reference in the constructor of my test controller was not getting injected with the concrete implementation (from the data project). I hit a brick wall with this so basically decided to switch out Castle Windsor for StructureMap. I think I have implemented this ok as everything compiles and runs and my controller ran ok when referencing a custom repository interface. It appears now that I have/or cannot now setup my generic interfaces up properly (I hope this makes sense so far as I am new to all this). When I use IRepository(Of T) (wanting it to be injected with a concrete implementation of Repository(Of Type)) in the controller constructor I am getting the following runtime error: "StructureMap Exception Code: 202 No Default Instance defined for PluginFamily SharpArch.Core.PersistenceSupport.IRepository`1[[DebtRemedy.Core.Page, DebtRemedy.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]], SharpArch.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=b5f559ae0ac4e006" Here are my code excerpts that I am using (my project is called DebtRemedy). My structuremap registry class Public Class DefaultRegistry Inherits Registry Public Sub New() ''//Generic Repositories AddGenericRepositories() ''//Custom Repositories AddCustomRepositories() ''//Application Services AddApplicationServices() ''//Validator [For](GetType(IValidator)).Use(GetType(Validator)) End Sub Private Sub AddGenericRepositories() ''//ForRequestedType(GetType(IRepository(Of ))).TheDefaultIsConcreteType(GetType(Repository(Of ))) [For](GetType(IEntityDuplicateChecker)).Use(GetType(EntityDuplicateChecker)) [For](GetType(IRepository(Of ))).Use(GetType(Repository(Of ))) [For](GetType(INHibernateRepository(Of ))).Use(GetType(NHibernateRepository(Of ))) [For](GetType(IRepositoryWithTypedId(Of ,))).Use(GetType(RepositoryWithTypedId(Of ,))) [For](GetType(INHibernateRepositoryWithTypedId(Of ,))).Use(GetType(NHibernateRepositoryWithTypedId(Of ,))) End Sub Private Sub AddCustomRepositories() Scan(AddressOf SetupCustomRepositories) End Sub Private Shared Sub SetupCustomRepositories(ByVal y As IAssemblyScanner) y.Assembly("DebtRemedy.Core") y.Assembly("DebtRemedy.Data") y.WithDefaultConventions() End Sub Private Sub AddApplicationServices() Scan(AddressOf SetupApplicationServices) End Sub Private Shared Sub SetupApplicationServices(ByVal y As IAssemblyScanner) y.Assembly("DebtRemedy.ApplicationServices") y.With(New FirstInterfaceConvention) End Sub End Class Public Class FirstInterfaceConvention Implements ITypeScanner Public Sub Process(ByVal type As Type, ByVal graph As PluginGraph) Implements ITypeScanner.Process If Not IsConcrete(type) Then Exit Sub End If ''//only works on concrete types Dim firstinterface = type.GetInterfaces().FirstOrDefault() ''//grabs first interface If firstinterface IsNot Nothing Then graph.AddType(firstinterface, type) Else ''//registers type ''//adds concrete types with no interfaces graph.AddType(type) End If End Sub End Class I have tried both ForRequestedType (which I think is now deprecated) and For. IRepository(Of T) lives in SharpArch.Core.PersistenceSupport. Repository(Of T) lives in SharpArch.Data.NHibernate. My servicelocator class Public Class StructureMapServiceLocator Inherits ServiceLocatorImplBase Private container As IContainer Public Sub New(ByVal container As IContainer) Me.container = container End Sub Protected Overloads Overrides Function DoGetInstance(ByVal serviceType As Type, ByVal key As String) As Object Return If(String.IsNullOrEmpty(key), container.GetInstance(serviceType), container.GetInstance(serviceType, key)) End Function Protected Overloads Overrides Function DoGetAllInstances(ByVal serviceType As Type) As IEnumerable(Of Object) Dim objList As New List(Of Object) For Each obj As Object In container.GetAllInstances(serviceType) objList.Add(obj) Next Return objList End Function End Class My controllerfactory class Public Class ServiceLocatorControllerFactory Inherits DefaultControllerFactory Protected Overloads Overrides Function GetControllerInstance(ByVal requestContext As RequestContext, ByVal controllerType As Type) As IController If controllerType Is Nothing Then Return Nothing End If Try Return TryCast(ObjectFactory.GetInstance(controllerType), Controller) Catch generatedExceptionName As StructureMapException System.Diagnostics.Debug.WriteLine(ObjectFactory.WhatDoIHave()) Throw End Try End Function End Class The initialise stuff in my gloabal.asax Dim container As IContainer = New Container(New DefaultRegistry) ControllerBuilder.Current.SetControllerFactory(New ServiceLocatorControllerFactory()) ServiceLocator.SetLocatorProvider(Function() New StructureMapServiceLocator(container)) My test controller Public Class DataCaptureController Inherits BaseController Private ReadOnly clientRepository As IClientRepository() Private ReadOnly pageRepository As IRepository(Of Page) Public Sub New(ByVal clientRepository As IClientRepository(), ByVal pageRepository As IRepository(Of Page)) Check.Require(clientRepository IsNot Nothing, "clientRepository may not be null") Check.Require(pageRepository IsNot Nothing, "pageRepository may not be null") Me.clientRepository = clientRepository Me.pageRepository = pageRepository End Sub Function Index() As ActionResult Return View() End Function The above works fine when I take out everything to do with the pageRepository which is IRepository(Of T). Any help with this would be greatly appreciated.

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  • Algorithms or patterns for a linked question and answer cost calculator

    - by kmc
    I've been asked to build an online calculator in PHP (and the Laravel framework). It will take the answers to a series of questions to estimate the cost of a home extension. For example, a couple of questions may be: What is the lie of your property? Flat, slightly inclined, heavily inclined. (these suggestive values could have specific values in the underlying calculator like, 0 degrees, 5 degrees, 10 degrees. What is your current flooring system? Wooden, or concrete? These would then impact the results of other questions. Once the size of the extension has been input, the lie of the land will affect how much site works will cost, and how much rubbish collection will cost. The second question will impact the cost of the extensions flooring, as stumping and laying floorboards is a different cost to laying foundations and a concrete slab. It will also influence what heating and cooling systems are available in the calculator. So it's VERY interlinked. The answer to any question can influence the options of other questions, and the end result. I'm having trouble figuring out an approach to this that will allow new options and questions to be plugged in at a later stage without having things too coupled. The Observer pattern, or Laravel's events may be handy, but currently the sheer breadth of the calculator has me struggling to gather my thoughts and see a sensible implementation. Are there any patterns or OO approaches that may help? Thanks!

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  • Pipe an infinite stream to internal loop?

    - by Sh3ljohn
    I've seen a lot of things about redirecting stdout to a TCP socket, but no real example of how to do it in practice, specifically when the output stream generated by the first "command" never ends. To talk about something concrete, let's take programs like servers that typically output their log endlessly to stdout (well, as long as they run). If you redirect the output to a log file on the disk, then this file is always open (therefore not readable by others?) and grows infinitely, which eventually is going to cause problems. This might be a nood question, but I don't know what it does or how to do it so. How to redirect the output of a command to the internal loop? I want to make sure that data is sent EVERY time something is written to stdout, and that the pipe won't wait for the command to end (never happens ideally!). Is that right? If 2 is true, is there a buffer system to send chunks of data once it reaches a certain size only? Could you give me concrete command line examples to do the above? Thanks in advance

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  • Use decorator and factory together to extend objects?

    - by TheClue
    I'm new to OOP and design pattern. I've a simple app that handles the generation of Tables, Columns (that belong to Table), Rows (that belong to Column) and Values (that belong to Rows). Each of these object can have a collection of Property, which is in turn defined as an enum. They are all interfaces: I used factories to get concrete instances of these products, depending on circumnstances. Now I'm facing the problem of extending these classes. Let's say I need another product called "SpecialTable" which in turn has some special properties or new methods like 'getSomethingSpecial' or an extended set of Property. The only way is to extend/specialize all my elements (ie. build a SpecialTableFactory, a SpecialTable interface and a SpecialTableImpl concrete)? What to do if, let's say, I plan to use standard methods like addRow(Column column, String name) that doesn't need to be specialized? I don't like the idea to inherit factories and interfaces, but since SpecialTable has more methods than Table i guess it cannot share the same factory. Am I wrong? Another question: if I need to define product properties at run time (a Table that is upgraded to SpecialTable at runtime), i guess i should use a decorator. Is it possible (and how) to combine both factory and decorator design? Is it better to use a State or Strategy pattern, instead?

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  • Upgraded to Ubuntu 13.10 - Apache not able to start

    - by 0R10N
    I updated to Ubuntu 13.10 (from Ubuntu 13.04) last weekend, and now Apache is not being able to start. It was working perfectly well until the upgraded, and I haven't changed anything myself. When I ran a restart this is what I get apache2: Syntax error on line 260 of /etc/apache2/apache2.conf: Could not open configuration file /etc/apache2/conf.d/: No such file or directory So, I created the directory, and then I get this: * Starting web server apache2 * * The apache2 configtest failed. Output of config test was: [Wed Oct 30 11:17:42.921934 2013] [proxy_html:notice] [pid 2496] AH01425: I18n support in mod_proxy_html requires mod_xml2enc. Without it, non-ASCII characters in proxied pages are likely to display incorrectly. AH00526: Syntax error on line 84 of /etc/apache2/apache2.conf: Invalid command 'LockFile', perhaps misspelled or defined by a module not included in the server configuration Action 'configtest' failed. The Apache error log may have more information. Thanks!

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  • May 20th Links: ASP.NET MVC, ASP.NET, .NET 4, VS 2010, Silverlight

    - by ScottGu
    Here is the latest in my link-listing series.  Also check out my VS 2010 and .NET 4 series and ASP.NET MVC 2 series for other on-going blog series I’m working on. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] ASP.NET MVC How to Localize an ASP.NET MVC Application: Michael Ceranski has a good blog post that describes how to localize ASP.NET MVC 2 applications. ASP.NET MVC with jTemplates Part 1 and Part 2: Steve Gentile has a nice two-part set of blog posts that demonstrate how to use the jTemplate and DataTable jQuery libraries to implement client-side data binding with ASP.NET MVC. CascadingDropDown jQuery Plugin for ASP.NET MVC: Raj Kaimal has a nice blog post that demonstrates how to implement a dynamically constructed cascading dropdownlist on the client using jQuery and ASP.NET MVC. How to Configure VS 2010 Code Coverage for ASP.NET MVC Unit Tests: Visual Studio enables you to calculate the “code coverage” of your unit tests.  This measures the percentage of code within your application that is exercised by your tests – and can give you a sense of how much test coverage you have.  Gunnar Peipman demonstrates how to configure this for ASP.NET MVC projects. Shrinkr URL Shortening Service Sample: A nice open source application and code sample built by Kazi Manzur that demonstrates how to implement a URL Shortening Services (like bit.ly) using ASP.NET MVC 2 and EF4.  More details here. Creating RSS Feeds in ASP.NET MVC: Damien Guard has a nice post that describes a cool new “FeedResult” class he created that makes it easy to publish and expose RSS feeds from within ASP.NET MVC sites. NoSQL with MongoDB, NoRM and ASP.NET MVC Part 1 and Part 2: Nice two-part blog series by Shiju Varghese on how to use MongoDB (a document database) with ASP.NET MVC.  If you are interested in document databases also make sure to check out the Raven DB project from Ayende. Using the FCKEditor with ASP.NET MVC: Quick blog post that describes how to use FCKEditor – an open source HTML Text Editor – with ASP.NET MVC. ASP.NET Replace Html.Encode Calls with the New HTML Encoding Syntax: Phil Haack has a good blog post that describes a useful way to quickly update your ASP.NET pages and ASP.NET MVC views to use the new <%: %> encoding syntax in ASP.NET 4.  I blogged about the new <%: %> syntax – it provides an easy and concise way to HTML encode content. Integrating Twitter into an ASP.NET Website using OAuth: Scott Mitchell has a nice article that describes how to take advantage of Twiter within an ASP.NET Website using the OAuth protocol – which is a simple, secure protocol for granting API access. Creating an ASP.NET report using VS 2010 Part 1, Part 2, and Part 3: Raj Kaimal has a nice three part set of blog posts that detail how to use SQL Server Reporting Services, ASP.NET 4 and VS 2010 to create a dynamic reporting solution. Three Hidden Extensibility Gems in ASP.NET 4: Phil Haack blogs about three obscure but useful extensibility points enabled with ASP.NET 4. .NET 4 Entity Framework 4 Video Series: Julie Lerman has a nice, free, 7-part video series on MSDN that walks through how to use the new EF4 capabilities with VS 2010 and .NET 4.  I’ll be covering EF4 in a blog series that I’m going to start shortly as well. Getting Lazy with System.Lazy: System.Lazy and System.Lazy<T> are new features in .NET 4 that provide a way to create objects that may need to perform time consuming operations and defer the execution of the operation until it is needed.  Derik Whittaker has a nice write-up that describes how to use it. LINQ to Twitter: Nifty open source library on Codeplex that enables you to use LINQ syntax to query Twitter. Visual Studio 2010 Using Intellitrace in VS 2010: Chris Koenig has a nice 10 minute video that demonstrates how to use the new Intellitrace features of VS 2010 to enable DVR playback of your debug sessions. Make the VS 2010 IDE Colors look like VS 2008: Scott Hanselman has a nice blog post that covers the Visual Studio Color Theme Editor extension – which allows you to customize the VS 2010 IDE however you want. How to understand your code using Dependency Graphs, Sequence Diagrams, and the Architecture Explorer: Jennifer Marsman has a nice blog post describes how to take advantage of some of the new architecture features within VS 2010 to quickly analyze applications and legacy code-bases. How to maintain control of your code using Layer Diagrams: Another great blog post by Jennifer Marsman that demonstrates how to setup a “layer diagram” within VS 2010 to enforce clean layering within your applications.  This enables you to enforce a compiler error if someone inadvertently violates a layer design rule. Collapse Selection in Solution Explorer Extension: Useful VS 2010 extension that enables you to quickly collapse “child nodes” within the Visual Studio Solution Explorer.  If you have deeply nested project structures this extension is useful. Silverlight and Windows Phone 7 Building a Simple Windows Phone 7 Application: A nice tutorial blog post that demonstrates how to take advantage of Expression Blend to create an animated Windows Phone 7 application. If you haven’t checked out my Windows Phone 7 Twitter Tutorial I also recommend reading that. Hope this helps, Scott P.S. If you haven’t already, check out this month’s "Find a Hoster” page on the www.asp.net website to learn about great (and very inexpensive) ASP.NET hosting offers.

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  • dynatree: how can i select child node programmatically

    - by Muhammad Adeel Zahid
    hello everyone i m using jquery's dynaTree in my application and i want to select the all the child nodes programmably when a node is selected. the structure of my tree is as follows <div id = "tree"> <ul> <li>package 1 <ul> <li>module 1.1 <ul> <li> document 1.1.1</li> <li> document 1.1.2</li> </ul> </li> <li>module 1.2 <ul> <li>document 1.2.1</li> <li>document 1.2.2</li> </ul> </li> </ul> </li> <li> package 2 <ul> <li> module 2.1 <ul> <li>document 2.1.1</li> <li>document 2.1.1</li> </ul> </li> </ul> </li> </ul> </div> now what i want is that when i click on tree node with title "package 1" all its child nodes i.e (module 1.1, document 1.1.1, document 1.1.2, module 1.2, document 1.2.1, document 1.2.2) should also be selected below is the approach i tried to use $("#tree").dynatree({ onSelect: function(flag, dtnode) { // This will happen each time a check box is selected/deselected var selectedNodes = dtnode.tree.getSelectedNodes(); var selectedKeys = $.map(selectedNodes, function(node) { //alert(node.data.key); return node.data.key; }); // Set the hidden input field's value to the selected items $('#SelectedItems').val(selectedKeys.join(",")); if (flag) { child = dtnode.childList; alert(child.length); for (i = 0; i < child.length; i++) { var x = child[i].select(true); alert(i); } } }, checkbox: true, onActivate: function(dtnode) { //alert("You activated " + dtnode.data.key); } }); in the if(flag) condition i get all the child nodes of element that is selected by user and it gives me the correct value that i can see from alert(child.length) statement. then i run the loop to select all the children but loop never goes beyond the statement var x = child[i].select(true); and i can never see the statement alert(i) being executed. the result of above statement is that if i select package 1, module 1.1 and document 1.1.1 is also selected but never does it execute alert(i) statement neither other children of package 1 are selected. in my view when first time child[i].select(true) statement is executed it also triggers the on select event of its children thus making a recursion kind of thing is my thinking correct? no matter recursion or what why on earth does it not complete the loop and execute very next instruction alert(i). please help me in solving this problem. i m dying to see that alert any suggestion and help is highly appriciated thanks Adeel

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  • Revisiting ANTS Performance Profiler 7.4

    - by James Michael Hare
    Last year, I did a small review on the ANTS Performance Profiler 6.3, now that it’s a year later and a major version number higher, I thought I’d revisit the review and revise my last post. This post will take the same examples as the original post and update them to show what’s new in version 7.4 of the profiler. Background A performance profiler’s main job is to keep track of how much time is typically spent in each unit of code. This helps when we have a program that is not running at the performance we expect, and we want to know where the program is experiencing issues. There are many profilers out there of varying capabilities. Red Gate’s typically seem to be the very easy to “jump in” and get started with very little training required. So let’s dig into the Performance Profiler. I’ve constructed a very crude program with some obvious inefficiencies. It’s a simple program that generates random order numbers (or really could be any unique identifier), adds it to a list, sorts the list, then finds the max and min number in the list. Ignore the fact it’s very contrived and obviously inefficient, we just want to use it as an example to show off the tool: 1: // our test program 2: public static class Program 3: { 4: // the number of iterations to perform 5: private static int _iterations = 1000000; 6: 7: // The main method that controls it all 8: public static void Main() 9: { 10: var list = new List<string>(); 11: 12: for (int i = 0; i < _iterations; i++) 13: { 14: var x = GetNextId(); 15: 16: AddToList(list, x); 17: 18: var highLow = GetHighLow(list); 19: 20: if ((i % 1000) == 0) 21: { 22: Console.WriteLine("{0} - High: {1}, Low: {2}", i, highLow.Item1, highLow.Item2); 23: Console.Out.Flush(); 24: } 25: } 26: } 27: 28: // gets the next order id to process (random for us) 29: public static string GetNextId() 30: { 31: var random = new Random(); 32: var num = random.Next(1000000, 9999999); 33: return num.ToString(); 34: } 35: 36: // add it to our list - very inefficiently! 37: public static void AddToList(List<string> list, string item) 38: { 39: list.Add(item); 40: list.Sort(); 41: } 42: 43: // get high and low of order id range - very inefficiently! 44: public static Tuple<int,int> GetHighLow(List<string> list) 45: { 46: return Tuple.Create(list.Max(s => Convert.ToInt32(s)), list.Min(s => Convert.ToInt32(s))); 47: } 48: } So let’s run it through the profiler and see what happens! Visual Studio Integration First, let’s look at how the ANTS profilers integrate with Visual Studio’s menu system. Once you install the ANTS profilers, you will get an ANTS menu item with several options: Notice that you can either Profile Performance or Launch ANTS Performance Profiler. These sound similar but achieve two slightly different actions: Profile Performance: this immediately launches the profiler with all defaults selected to profile the active project in Visual Studio. Launch ANTS Performance Profiler: this launches the profiler much the same way as starting it from the Start Menu. The profiler will pre-populate the application and path information, but allow you to change the settings before beginning the profile run. So really, the main difference is that Profile Performance immediately begins profiling with the default selections, where Launch ANTS Performance Profiler allows you to change the defaults and attach to an already-running application. Let’s Fire it Up! So when you fire up ANTS either via Start Menu or Launch ANTS Performance Profiler menu in Visual Studio, you are presented with a very simple dialog to get you started: Notice you can choose from many different options for application type. You can profile executables, services, web applications, or just attach to a running process. In fact, in version 7.4 we see two new options added: ASP.NET Web Application (IIS Express) SharePoint web application (IIS) So this gives us an additional way to profile ASP.NET applications and the ability to profile SharePoint applications as well. You can also choose your level of detail in the Profiling Mode drop down. If you choose Line-Level and method-level timings detail, you will get a lot more detail on the method durations, but this will also slow down profiling somewhat. If you really need the profiler to be as unintrusive as possible, you can change it to Sample method-level timings. This is performing very light profiling, where basically the profiler collects timings of a method by examining the call-stack at given intervals. Which method you choose depends a lot on how much detail you need to find the issue and how sensitive your program issues are to timing. So for our example, let’s just go with the line and method timing detail. So, we check that all the options are correct (if you launch from VS2010, the executable and path are filled in already), and fire it up by clicking the [Start Profiling] button. Profiling the Application Once you start profiling the application, you will see a real-time graph of CPU usage that will indicate how much your application is using the CPU(s) on your system. During this time, you can select segments of the graph and bookmark them, giving them mnemonic names. This can be useful if you want to compare performance in one part of the run to another part of the run. Notice that once you select a block, it will give you the call tree breakdown for that selection only, and the relative performance of those calls. Once you feel you have collected enough information, you can click [Stop Profiling] to stop the application run and information collection and begin a more thorough analysis. Analyzing Method Timings So now that we’ve halted the run, we can look around the GUI and see what we can see. By default, the times are shown in terms of percentage of time of the total run of the application, though you can change it in the View menu item to milliseconds, ticks, or seconds as well. This won’t affect the percentages of methods, it only affects what units the times are shown. Notice also that the major hotspot seems to be in a method without source, ANTS Profiler will filter these out by default, but you can right-click on the line and remove the filter to see more detail. This proves especially handy when a bottleneck is due to a method in the BCL. So now that we’ve removed the filter, we see a bit more detail: In addition, ANTS Performance Profiler gives you the ability to decompile the methods without source so that you can dive even deeper, though typically this isn’t necessary for our purposes. When looking at timings, there are generally two types of timings for each method call: Time: This is the time spent ONLY in this method, not including calls this method makes to other methods. Time With Children: This is the total of time spent in both this method AND including calls this method makes to other methods. In other words, the Time tells you how much work is being done exclusively in this method, and the Time With Children tells you how much work is being done inclusively in this method and everything it calls. You can also choose to display the methods in a tree or in a grid. The tree view is the default and it shows the method calls arranged in terms of the tree representing all method calls and the parent method that called them, etc. This is useful for when you find a hot-spot method, you can see who is calling it to determine if the problem is the method itself, or if it is being called too many times. The grid method represents each method only once with its totals and is useful for quickly seeing what method is the trouble spot. In addition, you can choose to display Methods with source which are generally the methods you wrote (as opposed to native or BCL code), or Any Method which shows not only your methods, but also native calls, JIT overhead, synchronization waits, etc. So these are just two ways of viewing the same data, and you’re free to choose the organization that best suits what information you are after. Analyzing Method Source If we look at the timings above, we see that our AddToList() method (and in particular, it’s call to the List<T>.Sort() method in the BCL) is the hot-spot in this analysis. If ANTS sees a method that is consuming the most time, it will flag it as a hot-spot to help call out potential areas of concern. This doesn’t mean the other statistics aren’t meaningful, but that the hot-spot is most likely going to be your biggest bang-for-the-buck to concentrate on. So let’s select the AddToList() method, and see what it shows in the source window below: Notice the source breakout in the bottom pane when you select a method (from either tree or grid view). This shows you the timings in this method per line of code. This gives you a major indicator of where the trouble-spot in this method is. So in this case, we see that performing a Sort() on the List<T> after every Add() is killing our performance! Of course, this was a very contrived, duh moment, but you’d be surprised how many performance issues become duh moments. Note that this one line is taking up 86% of the execution time of this application! If we eliminate this bottleneck, we should see drastic improvement in the performance. So to fix this, if we still wanted to maintain the List<T> we’d have many options, including: delay Sort() until after all Add() methods, using a SortedSet, SortedList, or SortedDictionary depending on which is most appropriate, or forgoing the sorting all together and using a Dictionary. Rinse, Repeat! So let’s just change all instances of List<string> to SortedSet<string> and run this again through the profiler: Now we see the AddToList() method is no longer our hot-spot, but now the Max() and Min() calls are! This is good because we’ve eliminated one hot-spot and now we can try to correct this one as well. As before, we can then optimize this part of the code (possibly by taking advantage of the fact the list is now sorted and returning the first and last elements). We can then rinse and repeat this process until we have eliminated as many bottlenecks as possible. Calls by Web Request Another feature that was added recently is the ability to view .NET methods grouped by the HTTP requests that caused them to run. This can be helpful in determining which pages, web services, etc. are causing hot spots in your web applications. Summary If you like the other ANTS tools, you’ll like the ANTS Performance Profiler as well. It is extremely easy to use with very little product knowledge required to get up and running. There are profilers built into the higher product lines of Visual Studio, of course, which are also powerful and easy to use. But for quickly jumping in and finding hot spots rapidly, Red Gate’s Performance Profiler 7.4 is an excellent choice. Technorati Tags: Influencers,ANTS,Performance Profiler,Profiler

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  • Trace Flag 610 – When should you use it?

    - by simonsabin
    Thanks to Marcel van der Holst for providing this great information on the use of Trace Flag 610. This trace flag can be used to have minimal logging into a b tree (i.e. clustered table or an index on a heap) that already has data. It is a trace flag because in testing they found some scenarios where it didn’t perform as well. Marcel explains why below. “ TF610 can be used to get minimal logging in a non-empty B-Tree. The idea is that when you insert a large amount of data, you don't want to...(read more)

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  • How to Search Just the Site You’re Viewing Using Google Search

    - by The Geek
    Have you ever wanted to search the site you’re viewing, but the built-in search box is either hard to find, or doesn’t work very well? Here’s how to add a special keyword bookmark that searches the site you’re viewing using Google’s site: search operator. This technique should work in either Google Chrome or Firefox—in Firefox you’ll want to create a regular bookmark and add the script into the keyword field, and for Google Chrome just follow the steps we’ve provided below Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? Simon’s Cat Explores the Christmas Tree! [Video] The Outdoor Lights Scene from National Lampoon’s Christmas Vacation [Video] The Famous Home Alone Pizza Delivery Scene [Classic Video] Chronicles of Narnia: The Voyage of the Dawn Treader Theme for Windows 7 Cardinal and Rabbit Sharing a Tree on a Cold Winter Morning Wallpaper An Alternate Star Wars Christmas Special [Video]

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  • ASP.NET MVC 3 Hosting :: ASP.NET MVC 3 First Look

    - by mbridge
    MVC 3 View Enhancements MVC 3 introduces two improvements to the MVC view engine: - Ability to select the view engine to use. MVC 3 allows you to select from any of your  installed view engines from Visual Studio by selecting Add > View (including the newly introduced ASP.NET “Razor” engine”): - Support for the next ASP.NET “Razor” syntax. The newly previewed Razor syntax is a concise lightweight syntax. MVC 3 Control Enhancements - Global Filters: ASP.NET MVC 3  allows you to specify that a filter which applies globally to all Controllers within an app by adding it to the GlobalFilters collection.  The RegisterGlobalFilters() method is now included in the default Global.asax class template and so provides a convenient place to do this since is will then be called by the Application_Start() method: void RegisterGlobalFilters(GlobalFilterCollection filters) { filters.Add(new HandleLoggingAttribute()); filters.Add(new HandleErrorAttribute()); } void Application_Start() { RegisterGlobalFilters (GlobalFilters.Filters); } - Dynamic ViewModel Property : MVC 3 augments the ViewData API with a new “ViewModel” property on Controller which is of type “dynamic” – and therefore enables you to use the new dynamic language support in C# and VB pass ViewData items using a cleaner syntax than the current dictionary API. Public ActionResult Index() { ViewModel.Message = "Hello World"; return View(); } - New ActionResult Types : MVC 3 includes three new ActionResult types and helper methods: 1. HttpNotFoundResult – indicates that a resource which was requested by the current URL was not found. HttpNotFoundResult will return a 404 HTTP status code to the calling client. 2. PermanentRedirects – The HttpRedirectResult class contains a new Boolean “Permanent” property which is used to indicate that a permanent redirect should be done. Permanent redirects use a HTTP 301 status code.  The Controller class  includes three new methods for performing these permanent redirects: RedirectPermanent(), RedirectToRoutePermanent(), andRedirectToActionPermanent(). All  of these methods will return an instance of the HttpRedirectResult object with the Permanent property set to true. 3. HttpStatusCodeResult – used for setting an explicit response status code and its associated description. MVC 3 AJAX and JavaScript Enhancements MVC 3 ships with built-in JSON binding support which enables action methods to receive JSON-encoded data and then model-bind it to action method parameters. For example a jQuery client-side JavaScript could define a “save” event handler which will be invoked when the save button is clicked on the client. The code in the event handler then constructs a client-side JavaScript “product” object with 3 fields with their values retrieved from HTML input elements. Finally, it uses jQuery’s .ajax() method to POST a JSON based request which contains the product to a /theStore/UpdateProduct URL on the server: $('#save').click(function () { var product = { ProdName: $('#Name').val() Price: $('#Price').val(), } $.ajax({ url: '/theStore/UpdateProduct', type: "POST"; data: JSON.stringify(widget), datatype: "json", contentType: "application/json; charset=utf-8", success: function () { $('#message').html('Saved').fadeIn(), }, error: function () { $('#message').html('Error').fadeIn(), } }); return false; }); MVC will allow you to implement the /theStore/UpdateProduct URL on the server by using an action method as below. The UpdateProduct() action method will accept a strongly-typed Product object for a parameter. MVC 3 can now automatically bind an incoming JSON post value to the .NET Product type on the server without having to write any custom binding. [HttpPost] public ActionResult UpdateProduct(Product product) { // save logic here return null } MVC 3 Model Validation Enhancements MVC 3 builds on the MVC 2 model validation improvements by adding   support for several of the new validation features within the System.ComponentModel.DataAnnotations namespace in .NET 4.0: - Support for the new DataAnnotations metadata attributes like DisplayAttribute. - Support for the improvements made to the ValidationAttribute class which now supports a new IsValid overload that provides more info on  the current validation context, like what object is being validated. - Support for the new IValidatableObject interface which enables you to perform model-level validation and also provide validation error messages which are specific to the state of the overall model. MVC 3 Dependency Injection Enhancements MVC 3 includes better support for applying Dependency Injection (DI) and also integrating with Dependency Injection/IOC containers. Currently MVC 3 Preview 1 has support for DI in the below places: - Controllers (registering & injecting controller factories and injecting controllers) - Views (registering & injecting view engines, also for injecting dependencies into view pages) - Action Filters (locating and  injecting filters) And this is another important blog about Microsoft .NET and technology: - Windows 2008 Blog - SharePoint 2010 Blog - .NET 4 Blog And you can visit here if you're looking for ASP.NET MVC 3 hosting

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  • Programming languages, positional languages and natural languages

    - by Vitalij Zadneprovskij
    Some programming languages are modeled on machine code, like assembly languages. Other languages are modeled on a natural language, the English language. Others are not modeled on either machine code or natural language. Languages such as PROLOG, for example, don't follow either model. I came across this Perl module Lingua::Romana::Perligata, that allows to write programs using a syntax that is very similar to Latin. Are there programming languages that have less positional syntax? Are there other languages or modules that allow you to write in syntaxes inspired by other natural languages, like French, Hebrew or Farsi? There is a very long list on Wikipedia, but most of those projects are dead. There is a related question on StackOverflow. The answer that was accepted is "Use Google".

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  • Silverlight Cream for March 06, 2010 -- #808

    - by Dave Campbell
    In this Issue: András Velvárt, felix corke, Colin Eberhardt, Christopher Bennage, Gergely Orosz, Entity Spaces Team Blog, Mike Taulty(-2-), Jit Ghosh, and Jesse Liberty. Shoutouts: Jeremy Likness expands on the Silverlight Team's post Vancouver Olympics - How'd We Do That? Gavin Wignall has a post up Creating a 360 photograph of an object with Silverlight Photosynth From SilverlightCream.com: Transforming an Ugly Duckling into a Graceful Swan With Expression Blend and Silverlight - Part 2 Intro Animation András Velvárt has part 2 of his Transformation series up at SilverlightShow... he's taking the initro animation to a new length, allowing playback even... cool video tutorial! Free Silverlight 4 beta skin! felix corke has a Silerlight 4 theme up for us all to use. If you like a dark theme like Blend, you'll like this... I like it! Linq to Visual Tree Colin Eberhardt has a great tutorial up for using LINQ to query the WPF or Silverlight Visual Tree while retaining the tree structure. He also has links out to other techniques. XAML Attributes on Separate Lines Christopher Bennage has a post up showing how to easily get all your XAML attributes on separate lines using a VS menu option... I didn't know that! Using built-in, embedded and streamed fonts in Silverlight Gergely Orosz has a post up at ScottLogic going over Fonts in Silverlight -- built-in, embedded, or streamed, and examples with code. EntitySpaces 2010 Two Part Series on Silverlight and WCF Entity Spaces Team Blog has a pair of videos up on Entity Spaces 2010, WCF, and Silverlight. Part 1 is the intro and explanation, part 2 is a full-up app demonstrating it. MEF, Silverlight and the DeploymentCatalog In an attempt to respond fully to a query, Mike Taulty literally pushed the record button and took off on what became a tutorial video on building a real Silverlight app utilizing MEF. Silverlight 4, Experiment with Pluggable Navigation and a WCF Data Service Mike Taulty has an experiment detailed on his blog about pluggable navigation and Silverlight 4. He walks through the history of how we got to this point then takes on in an example... good external links too Enhancing Silverlight Video Experiences with Contextual Data This is a post on the MSDN Magazine site where Jit Ghosh has a great long post about not only Smooth Streaming with Silverlight, but also adding context data to your video. When Is It OK To Hack? Read what all Jesse Liberty gets involved in when he's trying to get something out the door and has to work around a problem. Just about as interesting are the comments ... check it out and leave your own! Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    MIX10

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  • VBoxManage modifyhd --resize doesn't exist?

    - by George Korac
    I'm trying to increase the size of a VirtualBox Win7 .vdi disk on Ubuntu 10.04 but when I try executing VBoxManage modifyhd /path/disk.vdi --resize 15360 it returns Syntax error: unknown option: --resize. I'm unsure as to why this is happening because I've used it before and it's still listed under valid options for VBoxManage modifyhd in the VirualBox User Manual . Cheers, George @maniat1k george@george-laptop:~$ VBoxManage modifyhd '/home/george/.VirtualBox/HardDisks/Windows 7 64bit.vdi' --resize 15360 Sun VirtualBox Command Line Management Interface Version 3.1.6_OSE (C) 2005-2010 Sun Microsystems, Inc. All rights reserved. Usage: VBoxManage modifyhd | [--type normal|writethrough|immutable] [--autoreset on|off] [--compact] Syntax error: unknown option: --resize

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  • How to remove old Linux kernel modules »tp_smapi«?

    - by user43816
    ~$ locate tp_smapi /lib/modules/3.0.0-19-generic/updates/dkms/tp_smapi.ko /lib/modules/3.2.0-26-generic/updates/dkms/tp_smapi.ko /lib/modules/3.2.0-29-generic/updates/dkms/tp_smapi.ko /usr/src/tp-smapi-0.41/tp_smapi.c /var/lib/dkms/tp-smapi/0.41/3.0.0-19-generic/x86_64/module/tp_smapi.ko /var/lib/dkms/tp-smapi/0.41/3.2.0-26-generic/x86_64/module/tp_smapi.ko /var/lib/dkms/tp-smapi/0.41/3.2.0-29-generic/x86_64/module/tp_smapi.ko /var/lib/dkms/tp-smapi/0.41/build/tp_smapi.c' How to remove the 2 old Linux kernel modules from kernels 3.0.0-19 und 3.2.0-26? ~$ man dkms "'dkms remove [module/module-version]' removes a module/version combination from a tree.' What is a "[module/module-version]", please? Please notice: I do not want to remove old Linux kernel modules tp_smapi from a tree but I'd like to remove old Linux kernel modules from my Ubuntu 12.04.1 computer.

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  • Nant COM Reference [migrated]

    - by user29286
    I'm trying to find the Nant syntax for including a COM reference. The current Nant script with the normal dll reference looks like .. <references> <include name="${external-lib}/System.Interop.AppName.dll" /> The COM reference in the .csproj file looks like this ... <COMReference Include="System.Interop.AppName"> <Guid>{00020813-0000-0000-C000-000000000046}</Guid> <VersionMajor>1</VersionMajor> <VersionMinor>7</VersionMinor> <Lcid>0</Lcid> <WrapperTool>primary</WrapperTool> <Isolated>False</Isolated> </COMReference> What syntax should I use in Nant to swap to the COM reference to do the build ?

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  • How to grant write permissions in Samba?

    - by Eric Fossum
    I'm having trouble with read/write permissions on my Samba server, how do I fix my smb.conf and file permissions to have a more unified access? smb.conf [global] workgroup = workgroup netbios name = LnxNAS server string = %h wins support = no dns proxy = no security = user encrypt passwords = yes panic action = /usr/share/samba/panic-action %d [homes] comment = Home Directories [Video] path = /data/eric/Videos [Music] path = /data/eric/Music [Pictures] path = /data/eric/Pictures [data] path = /data my ls -l of /data/eric/Pictures drwxrwxrwx 2 ericfoss root 4096 2011-03-13 22:09 Android Projs drwxrwxrwx 3 ericfoss root 4096 2011-03-13 22:09 Automotive -rwxrwxrwx 1 ericfoss root 2439 2010-12-17 17:03 BDD reduction.png -rwxrwxrwx 1 ericfoss root 2722 2010-12-17 16:55 BDD Tree.png -rwxrwxrwx 1 ericfoss root 7341 2010-12-17 16:46 BDD Tree.xcf -rwxrwxrwx 1 ericfoss root 72421 2007-11-22 22:59 Bum Ninja.jpg -rwxrwxrwx 1 ericfoss root 32152 2010-12-17 21:25 cell transition.png -rwxrwxrwx 1 ericfoss root 40212 2010-12-17 17:55 control graph.png drwxrwxrwx 2 ericfoss root 4096 2011-03-13 22:09 Crap -rwxrwxrwx 1 ericfoss root 82 2010-09-20 17:18 desktop.ini ericfoss@SERVER:~$ If I try to delete \Server\Pictures\Crap it says permission denied, but \Server\data\eric\Pictures\crap can be deleted... I thought security = user took care of this?

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  • Unable install cmake and ccmake?

    - by user159618
    So the thing is I'm trying to install Cmake and cmake-curses-gui. I have updated the system with apt-get-update. sudo apt-get install cmake Reading package lists... Done Building dependency tree Reading state information... Done Package cmake is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'cmake' has no installation candidate sudo apt-get install cmake-curses-gui Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package cmake-curses-gui That's strange. Can anyone give some pointers? Pastbin sources.list :- http://pastebin.com/DufycYfZ

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  • Data structure: sort and search effectively

    - by Jiten Shah
    I need to have a data structure with say 4 keys . I can sort on any of these keys. What data structure can I opt for? Sorting time should be very little. I thought of a tree, but it will be only help searching on one key. For other keys I'll have to remake the tree on that particular key and then find it. Is there any data structure that can take care of all 4 keys at the same time? these 4 fields are of total 12 bytes and total size for each record - 40 bytes.. have memory constraints too... operations are : insertion, deletion, sorting on different keys.

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  • How to detect two moving shapes overlapped?

    - by user1389813
    Given a list of circles with its coordinates (x and y) that are moving every second in different direction (South-East, South-West, North-East and North-West), and the circle will change direction if it hits the wall sort of like bouncing, so how do we detect if any of them collide or overlap with each other ? I am not sure if we can use some data structures like a Binary Search Tree because since all the coordinates vary every seconds, so the tree will have to re-build accordingly. Or can we use Vertical Sweep Line Algorithm each time ? Any ideas on how to do this in a efficient way ?

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  • Difference between $ and # in ADF/JSF/JSP

    - by pavan.pvj
    Found this one interesting. So, picked it from one of the books and posting here.JSP 2.1 and JSF 1.2 - both of them use a unified Expression language. One major and the most obvious difference is between $ and #. JSP 2.1 uses $ and JSF 1.2 uses # in an EL. $ - immediate evaluation# - deferred evaluation$ - $ syntax executes expressions eagerly/immediately, which means that the result is returned immediately when the page renders.# - # syntax defers the expression evaluation to a point defined by the implementing technology. In general, JSF uses deferred EL evaluation because of its multiple lifecycle phases in which events are handled. To ensure the model is prepared before the values are accessed by EL, it must defer EL evaluation until the appropriate point in the life cycle.Note: This is picked up from Oracle Fusion Developer Guide (ISBN: 9780071622547). There is also a very good article here:http://java.sun.com/products/jsp/reference/techart/unifiedEL.html

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  • Spooling in SQL execution plans

    - by Rob Farley
    Sewing has never been my thing. I barely even know the terminology, and when discussing this with American friends, I even found out that half the words that Americans use are different to the words that English and Australian people use. That said – let’s talk about spools! In particular, the Spool operators that you find in some SQL execution plans. This post is for T-SQL Tuesday, hosted this month by me! I’ve chosen to write about spools because they seem to get a bad rap (even in my song I used the line “There’s spooling from a CTE, they’ve got recursion needlessly”). I figured it was worth covering some of what spools are about, and hopefully explain why they are remarkably necessary, and generally very useful. If you have a look at the Books Online page about Plan Operators, at http://msdn.microsoft.com/en-us/library/ms191158.aspx, and do a search for the word ‘spool’, you’ll notice it says there are 46 matches. 46! Yeah, that’s what I thought too... Spooling is mentioned in several operators: Eager Spool, Lazy Spool, Index Spool (sometimes called a Nonclustered Index Spool), Row Count Spool, Spool, Table Spool, and Window Spool (oh, and Cache, which is a special kind of spool for a single row, but as it isn’t used in SQL 2012, I won’t describe it any further here). Spool, Table Spool, Index Spool, Window Spool and Row Count Spool are all physical operators, whereas Eager Spool and Lazy Spool are logical operators, describing the way that the other spools work. For example, you might see a Table Spool which is either Eager or Lazy. A Window Spool can actually act as both, as I’ll mention in a moment. In sewing, cotton is put onto a spool to make it more useful. You might buy it in bulk on a cone, but if you’re going to be using a sewing machine, then you quite probably want to have it on a spool or bobbin, which allows it to be used in a more effective way. This is the picture that I want you to think about in relation to your data. I’m sure you use spools every time you use your sewing machine. I know I do. I can’t think of a time when I’ve got out my sewing machine to do some sewing and haven’t used a spool. However, I often run SQL queries that don’t use spools. You see, the data that is consumed by my query is typically in a useful state without a spool. It’s like I can just sew with my cotton despite it not being on a spool! Many of my favourite features in T-SQL do like to use spools though. This looks like a very similar query to before, but includes an OVER clause to return a column telling me the number of rows in my data set. I’ll describe what’s going on in a few paragraphs’ time. So what does a Spool operator actually do? The spool operator consumes a set of data, and stores it in a temporary structure, in the tempdb database. This structure is typically either a Table (ie, a heap), or an Index (ie, a b-tree). If no data is actually needed from it, then it could also be a Row Count spool, which only stores the number of rows that the spool operator consumes. A Window Spool is another option if the data being consumed is tightly linked to windows of data, such as when the ROWS/RANGE clause of the OVER clause is being used. You could maybe think about the type of spool being like whether the cotton is going onto a small bobbin to fit in the base of the sewing machine, or whether it’s a larger spool for the top. A Table or Index Spool is either Eager or Lazy in nature. Eager and Lazy are Logical operators, which talk more about the behaviour, rather than the physical operation. If I’m sewing, I can either be all enthusiastic and get all my cotton onto the spool before I start, or I can do it as I need it. “Lazy” might not the be the best word to describe a person – in the SQL world it describes the idea of either fetching all the rows to build up the whole spool when the operator is called (Eager), or populating the spool only as it’s needed (Lazy). Window Spools are both physical and logical. They’re eager on a per-window basis, but lazy between windows. And when is it needed? The way I see it, spools are needed for two reasons. 1 – When data is going to be needed AGAIN. 2 – When data needs to be kept away from the original source. If you’re someone that writes long stored procedures, you are probably quite aware of the second scenario. I see plenty of stored procedures being written this way – where the query writer populates a temporary table, so that they can make updates to it without risking the original table. SQL does this too. Imagine I’m updating my contact list, and some of my changes move data to later in the book. If I’m not careful, I might update the same row a second time (or even enter an infinite loop, updating it over and over). A spool can make sure that I don’t, by using a copy of the data. This problem is known as the Halloween Effect (not because it’s spooky, but because it was discovered in late October one year). As I’m sure you can imagine, the kind of spool you’d need to protect against the Halloween Effect would be eager, because if you’re only handling one row at a time, then you’re not providing the protection... An eager spool will block the flow of data, waiting until it has fetched all the data before serving it up to the operator that called it. In the query below I’m forcing the Query Optimizer to use an index which would be upset if the Name column values got changed, and we see that before any data is fetched, a spool is created to load the data into. This doesn’t stop the index being maintained, but it does mean that the index is protected from the changes that are being done. There are plenty of times, though, when you need data repeatedly. Consider the query I put above. A simple join, but then counting the number of rows that came through. The way that this has executed (be it ideal or not), is to ask that a Table Spool be populated. That’s the Table Spool operator on the top row. That spool can produce the same set of rows repeatedly. This is the behaviour that we see in the bottom half of the plan. In the bottom half of the plan, we see that the a join is being done between the rows that are being sourced from the spool – one being aggregated and one not – producing the columns that we need for the query. Table v Index When considering whether to use a Table Spool or an Index Spool, the question that the Query Optimizer needs to answer is whether there is sufficient benefit to storing the data in a b-tree. The idea of having data in indexes is great, but of course there is a cost to maintaining them. Here we’re creating a temporary structure for data, and there is a cost associated with populating each row into its correct position according to a b-tree, as opposed to simply adding it to the end of the list of rows in a heap. Using a b-tree could even result in page-splits as the b-tree is populated, so there had better be a reason to use that kind of structure. That all depends on how the data is going to be used in other parts of the plan. If you’ve ever thought that you could use a temporary index for a particular query, well this is it – and the Query Optimizer can do that if it thinks it’s worthwhile. It’s worth noting that just because a Spool is populated using an Index Spool, it can still be fetched using a Table Spool. The details about whether or not a Spool used as a source shows as a Table Spool or an Index Spool is more about whether a Seek predicate is used, rather than on the underlying structure. Recursive CTE I’ve already shown you an example of spooling when the OVER clause is used. You might see them being used whenever you have data that is needed multiple times, and CTEs are quite common here. With the definition of a set of data described in a CTE, if the query writer is leveraging this by referring to the CTE multiple times, and there’s no simplification to be leveraged, a spool could theoretically be used to avoid reapplying the CTE’s logic. Annoyingly, this doesn’t happen. Consider this query, which really looks like it’s using the same data twice. I’m creating a set of data (which is completely deterministic, by the way), and then joining it back to itself. There seems to be no reason why it shouldn’t use a spool for the set described by the CTE, but it doesn’t. On the other hand, if we don’t pull as many columns back, we might see a very different plan. You see, CTEs, like all sub-queries, are simplified out to figure out the best way of executing the whole query. My example is somewhat contrived, and although there are plenty of cases when it’s nice to give the Query Optimizer hints about how to execute queries, it usually doesn’t do a bad job, even without spooling (and you can always use a temporary table). When recursion is used, though, spooling should be expected. Consider what we’re asking for in a recursive CTE. We’re telling the system to construct a set of data using an initial query, and then use set as a source for another query, piping this back into the same set and back around. It’s very much a spool. The analogy of cotton is long gone here, as the idea of having a continual loop of cotton feeding onto a spool and off again doesn’t quite fit, but that’s what we have here. Data is being fed onto the spool, and getting pulled out a second time when the spool is used as a source. (This query is running on AdventureWorks, which has a ManagerID column in HumanResources.Employee, not AdventureWorks2012) The Index Spool operator is sucking rows into it – lazily. It has to be lazy, because at the start, there’s only one row to be had. However, as rows get populated onto the spool, the Table Spool operator on the right can return rows when asked, ending up with more rows (potentially) getting back onto the spool, ready for the next round. (The Assert operator is merely checking to see if we’ve reached the MAXRECURSION point – it vanishes if you use OPTION (MAXRECURSION 0), which you can try yourself if you like). Spools are useful. Don’t lose sight of that. Every time you use temporary tables or table variables in a stored procedure, you’re essentially doing the same – don’t get upset at the Query Optimizer for doing so, even if you think the spool looks like an expensive part of the query. I hope you’re enjoying this T-SQL Tuesday. Why not head over to my post that is hosting it this month to read about some other plan operators? At some point I’ll write a summary post – once I have you should find a comment below pointing at it. @rob_farley

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  • Do you play Sudoku ?

    - by Gilles Haro
    Did you know that 11gR2 database could solve a Sudoku puzzle with a single query and, most of the time, and this in less than a second ? The following query shows you how ! Simply pass a flattened Sudoku grid to it a get the result instantaneously ! col "Solution" format a9 col "Problem" format a9 with Iteration( initialSudoku, Step, EmptyPosition ) as ( select initialSudoku, InitialSudoku, instr( InitialSudoku, '-' )        from ( select '--64----2--7-35--1--58-----27---3--4---------4--2---96-----27--7--58-6--3----18--' InitialSudoku from dual )    union all    select initialSudoku        , substr( Step, 1, EmptyPosition - 1 ) || OneDigit || substr( Step, EmptyPosition + 1 )         , instr( Step, '-', EmptyPosition + 1 )      from Iteration         , ( select to_char( rownum ) OneDigit from dual connect by rownum <= 9 ) OneDigit     where EmptyPosition > 0       and not exists          ( select null              from ( select rownum IsPossible from dual connect by rownum <= 9 )             where OneDigit = substr( Step, trunc( ( EmptyPosition - 1 ) / 9 ) * 9 + IsPossible, 1 )   -- One line must contain the 1-9 digits                or OneDigit = substr( Step, mod( EmptyPosition - 1, 9 ) - 8 + IsPossible * 9, 1 )      -- One row must contain the 1-9 digits                or OneDigit = substr( Step, mod( trunc( ( EmptyPosition - 1 ) / 3 ), 3 ) * 3           -- One square must contain the 1-9 digits                            + trunc( ( EmptyPosition - 1 ) / 27 ) * 27 + IsPossible                            + trunc( ( IsPossible - 1 ) / 3 ) * 6 , 1 )          ) ) select initialSudoku "Problem", Step "Solution"    from Iteration  where EmptyPosition = 0 ;   The Magic thing behind this is called Recursive Subquery Factoring. The Oracle documentation gives the following definition: If a subquery_factoring_clause refers to its own query_name in the subquery that defines it, then the subquery_factoring_clause is said to be recursive. A recursive subquery_factoring_clause must contain two query blocks: the first is the anchor member and the second is the recursive member. The anchor member must appear before the recursive member, and it cannot reference query_name. The anchor member can be composed of one or more query blocks combined by the set operators: UNION ALL, UNION, INTERSECT or MINUS. The recursive member must follow the anchor member and must reference query_name exactly once. You must combine the recursive member with the anchor member using the UNION ALL set operator. This new feature is a replacement of this old Hierarchical Query feature that exists in Oracle since the days of Aladdin (well, at least, release 2 of the database in 1977). Everyone remembers the old syntax : select empno, ename, job, mgr, level      from   emp      start with mgr is null      connect by prior empno = mgr; that could/should be rewritten (but not as often as it should) as withT_Emp (empno, name, level) as        ( select empno, ename, job, mgr, level             from   emp             start with mgr is null             connect by prior empno = mgr        ) select * from   T_Emp; which uses the "with" syntax, whose main advantage is to clarify the readability of the query. Although very efficient, this syntax had the disadvantage of being a Non-Ansi Sql Syntax. Ansi-Sql version of Hierarchical Query is called Recursive Subquery Factoring. As of 11gR2, Oracle got compliant with Ansi Sql and introduced Recursive Subquery Factoring. It is basically an extension of the "With" clause that enables recursion. Now, the new syntax for the query would be with T_Emp (empno, name, job, mgr, hierlevel) as       ( select E.empno, E.ename, E.job, E.mgr, 1 from emp E where E.mgr is null         union all         select E.empno, E.ename, E.job, E.mgr, T.hierlevel + 1from emp E                                                                                                            join T_Emp T on ( E.mgr = T.empno ) ) select * from   T_Emp; The anchor member is a replacement for the "start with" The recursive member is processed through iterations. It joins the Source table (EMP) with the result from the Recursive Query itself (T_Emp) Each iteration works with the results of all its preceding iterations.     Iteration 1 works on the results of the first query     Iteration 2 works on the results of Iteration 1 and first query     Iteration 3 works on the results of Iteration 1, Iteration 2 and first query. So, knowing that, the Sudoku query it self-explaining; The anchor member contains the "Problem" : The Initial Sudoku and the Position of the first "hole" in the grid. The recursive member tries to replace the considered hole with any of the 9 digit that would satisfy the 3 rules of sudoku Recursion progress through the grid until it is complete.   Another example :  Fibonaccy Numbers :  un = (un-1) + (un-2) with Fib (u1, u2, depth) as   (select 1, 1, 1 from dual    union all    select u1+u2, u1, depth+1 from Fib where depth<10) select u1 from Fib; Conclusion Oracle brings here a new feature (which, to be honest, already existed on other concurrent systems) and extends the power of the database to new boundaries. It’s now up to developers to try and test it and find more useful application than solving puzzles… But still, solving a Sudoku in less time it takes to say it remains impressive… Interesting links: You might be interested by the following links which cover different aspects of this feature Oracle Documentation Lucas Jellema 's Blog Fibonaci Numbers

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