cache invalidation - Page 209

Howto detect fake RAM

- by Michael

I just bought a virtual server which should have 2GB of RAM. Now i got a server with 4gb which looks very strange to me. I think it is just a virtual RAM. dmidecode only ouputs /dev/mem: Operation not permitted How can i check if it's a real RAM or just a virtual one? free -m outputs: total used free shared buffers cached Mem: 4093 364 3728 0 0 346 -/+ buffers/cache: 18 4074 Swap: 0 0 0 Output from cat /proc/user_beancounters Version: 2.5 uid resource held maxheld barrier limit failcnt 137: kmemsize 8922287 10194944 2145910784 2145910784 0 lockedpages 0 0 523904 523904 0 privvmpages 13387 59112 9223372036854775807 9223372036854775807 0 shmpages 769 785 9223372036854775807 9223372036854775807 0 dummy 0 0 9223372036854775807 9223372036854775807 0 numproc 22 54 9223372036854775807 9223372036854775807 0 physpages 93377 106010 0 1047808 0 vmguarpages 0 0 9223372036854775807 9223372036854775807 0 oomguarpages 2471 2473 9223372036854775807 9223372036854775807 0 numtcpsock 5 21 9223372036854775807 9223372036854775807 0 numflock 4 13 9223372036854775807 9223372036854775807 0 numpty 1 1 9223372036854775807 9223372036854775807 0 numsiginfo 0 39 9223372036854775807 9223372036854775807 0 tcpsndbuf 102592 381632 9223372036854775807 9223372036854775807 0 tcprcvbuf 81920 4820184 9223372036854775807 9223372036854775807 0 othersockbuf 4624 61632 9223372036854775807 9223372036854775807 0 dgramrcvbuf 0 9248 9223372036854775807 9223372036854775807 0 numothersock 39 56 9223372036854775807 9223372036854775807 0 dcachesize 4178917 4232732 1072955392 1072955392 0 numfile 378 535 9223372036854775807 9223372036854775807 0 dummy 0 0 9223372036854775807 9223372036854775807 0 dummy 0 0 9223372036854775807 9223372036854775807 0 dummy 0 0 9223372036854775807 9223372036854775807 0 numiptent 24 24 9223372036854775807 9223372036854775807 0

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Mac OS X - Time Machine backup fails verification - What can I do to save the history?

- by usermac75

Hi, How do I make Time Machine to make a new complete backup without losing older versions of backed up files? Verbose: I am using the Time Machine backup on my OS X (Snow Leopard) to backup the whole computer to an external drive. I especially like the "history", i.e. the feature that allows you to restore the older version of a file. Problem: I had some data corruption on my external backup drive, I repaired it with the System Tool for doing that, it found some faults. I had the disk tool repair the external drive. After that, the external drive was OK and I could use Time Machine again. I let Time Machine do one more backup. Now I made a verification according to http://superuser.com/questions/47628/verifying-time-machine-backups, namely along sudo diff -qr . $HOME/Desktop 2>&1 | tee $HOME/timemachine-diff.log However: After doing the command above, several differences and missing files were reported, approx. 200 files in sum. Whereas some of the missing files were cache or excluded directories, the differences do bother me, especially as some important documents from me are listed as differing. How can I make sure that the data on the external drive is synced correctly? Is it possible to have Time Machine to do a complete new backup without losing the history? Or to have Time Machine compare all files for differences and re-write all files that are different? Or can I set some flags on the files that do not match to have them copied again? (like the archive-flag in Windows/Dos). I'd rather not touch the files because I would like to keep the date of last change/date of creation) Thank you for your thoughts!

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Can't reach only certain websites from my Wifi (with macbook and iphone)

- by trampj

I can't access certain websites neither from my macbook nor from my iphone when connected to my Wifi. The same website can be opened from another windows computer connected to the same Wifi. This is what happens when I try to ping it: PING ilpost.it (151.1.175.113): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 ... And when I try to traceroute it: host-001:~ j$ traceroute www.ilpost.it traceroute to ilpost.it (151.1.175.113), 64 hops max, 52 byte packets 1 vodafonedslrouter (192.168.1.1) 2.965 ms 0.743 ms 0.745 ms 2 * 2.96.54.77.rev.vodafone.pt (77.54.96.2) 12.076 ms 10.871 ms 3 77.41.30.213.rev.vodafone.pt (213.30.41.77) 14.145 ms 10.693 ms 11.960 ms 4 85.205.11.49 (85.205.11.49) 9.658 ms 8.946 ms 9.085 ms 5 85.205.13.105 (85.205.13.105) 57.497 ms 57.621 ms 48.080 ms 6 188.111.129.17 (188.111.129.17) 49.483 ms 51.338 ms 48.852 ms 7 85.205.25.174 (85.205.25.174) 47.891 ms 49.219 ms 47.821 ms 8 * * * 9 * * * 10 * * * 11 * * * I've flushed my DNS cache but nothing changed. This is quite dramatic as it seems to depend on 85.205.25.174 hop and don't know how to avoid it. Any suggestions? I add that 3 days ago everything worked fine. Then it has stopped.

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Can't reach only certain websites from my Wifi (with macbook and iphone)

- by mellin

I can't access certain websites neither from my macbook nor from my iphone when connected to my Wifi. The same website can be opened from another windows computer connected to the same Wifi. This is what happens when I try to ping it: PING ilpost.it (151.1.175.113): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 ... And when I try to traceroute it: host-001:~ j$ traceroute www.ilpost.it traceroute to ilpost.it (151.1.175.113), 64 hops max, 52 byte packets 1 vodafonedslrouter (192.168.1.1) 2.965 ms 0.743 ms 0.745 ms 2 * 2.96.54.77.rev.vodafone.pt (77.54.96.2) 12.076 ms 10.871 ms 3 77.41.30.213.rev.vodafone.pt (213.30.41.77) 14.145 ms 10.693 ms 11.960 ms 4 85.205.11.49 (85.205.11.49) 9.658 ms 8.946 ms 9.085 ms 5 85.205.13.105 (85.205.13.105) 57.497 ms 57.621 ms 48.080 ms 6 188.111.129.17 (188.111.129.17) 49.483 ms 51.338 ms 48.852 ms 7 85.205.25.174 (85.205.25.174) 47.891 ms 49.219 ms 47.821 ms 8 * * * 9 * * * 10 * * * 11 * * * I've flushed my DNS cache but nothing changed. This is quite dramatic as it seems to depend on 85.205.25.174 hop and don't know how to avoid it. Any suggestions? I add that 3 days ago everything worked fine. Then it has stopped.

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IE8 page reload hangs

- by Rod

When a 7mb HTM file is first opened (by clicking on the file icon or using Open With), both IE8 and Firefox display this browser file quickly. After the file is closed, Firefox will reopen this file quickly, but IE8 appears to hang during the reopen. Clearing the IE cache does not help. However, IE will reopen the file quickly again only if the File/Open/Browse feature of the menu bar is used (clicking on the file icon can be used only once between computer reboots). Testing suggests that the problem relates to the number of HTML hyperlinks pointing to another part of the file. There are many hyperlinks, but they are not a problem during the first load of the document (between computer reboots). What needs to be fixed to avoid use of the workaround? Using Windows XP SP3 Update 6/23/12 - Controlled testing shows that the number of hyperlinks is not the problem. The way this large file is opened is the difference: 1) from the IE menu bar, File/Open/Browse is consistent and fast (but not as fast as FF). 2) clicking on the file name in the folder (even when IE is the default program for this file type) causes a much delayed load of the file. Creating a smaller file demonstrates the delayed load, but verifies that the load eventually occurs.

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Nginx and 1000 WordPress Installs - Optimization

- by GTE

Hey, I'm trying to create a rather unusual (imo) configuration where I have: nginx php-fastcgi mysql 1000 seperate WordPress installs (with WP Super Cache). Each WP install corresponds to a seperate subdomain. Furthermore, I have 1000 cron jobs being called every hour that in turn call a WP plugin (using wget) which retrieves data from an API and posts it to the respective blog. This is all being run on a virtual server with 1024MB of RAM, 4 shared processors, etc. The server is not doing well, especially during the times that the cron jobs are being executed. Nginx constantly throws 504 errors and the site has a significant lag. 1) Am I crazy for having 1000 individual WP installs? Should I be using WP-MU and will this help significantly? (I have certain plugin restrictions that I prefer having seperate installs but could switch if need be.) 2) Instead of having 1000 unique cron jobs - should be calling say a bash script that will then process the 1000 HTTP requests I need? Could this be done in a succesive order instead of a sequential one? 3) Any other kind of suggestion you may have for optimization? Should I be proxying to Apache instead of just using nginx, etc. Any kind of advice would be appreciated. Thanks in advance

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System requirements for running windows 8 (basic office use) in virtualbox (ubuntu as host os)

- by Tor Thommesen

I want to run windows 8 as a guest os with virtualbox on some thinkpad (haven't bought one yet) running Ubuntu 12.04. Apart from virtualizing windows 8 (mostly just for use with the office suite app) my needs are very modest, I don't need much more than emacs and a browser. What I'd like to know is what kind of specs will be necessary to run windows 8 well as a vm, using the office apps. It would be a shame to waste money on overpowered hardware. Are there any official guidelines from oracle or windows on this? Would this lenovo x220, for example, be sufficiently strong? The specs below were taken from this review. Intel Core i5-2520M dual-core processor (2.5GHz, 3MB cache, 3.2GHz Turbo frequency) Windows 7 Professional (64-bit) 12.5-inch Premium HD (1366 x 768) LED Backlit Display (IPS) Intel Integrated HD Graphics 4GB DDR3 (1333MHz) 320GB Hitachi Travelstar hard drive (Z7K320) Intel Centrino Advanced-N 6205 (Taylor Peak) 2x2 AGN wireless card Intel 82579LM Gigabit Ethernet 720p High Definition webcam Fingerprint reader 6-cell battery (63Wh) and optional slice battery (65Wh) Dimensions: 12 (L) x 8.2 (W) x 0.5-1.5 (H) inches with 6-cell battery Weight: 3.5 pounds with 6-cell battery 4.875 pounds with 6-cell battery and optional external battery slice Price as configured: $1,299.00 (starting at $979.00)

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Building a small server farm

- by RayQuang

Hi, I am planning to set up a Tech startup company that will provide web application solutions. Eventually we hope to diversify into different areas such as possibly social media or other services. For now we plan on running a high demand (from 1000 to 10,000 users in the first year) website running the application. This includes a MySQL database backend, email, and development servers. My question is then, what type of server arrangement will work best, that is ti say should i have a small cluster of ultra high power machines (E.G. Top of the range Xeons, with 12GB RAM) or will it be better to have more less powerful servers load balanced? Should I go for 1 - 2 u servers rack mounted ot would it be beter for it just to be tower servers for maintainability? Finally I would also like to know what kind of Internet and router i would need, I currently have 10mbit down and barely 1 mbit up, but soon our area will have a fiber optic connection with international speeds of up to 25 mbit / sec. Thanks in advance, RayQuang UPDATE: sorry I forgot to mention it, the platform that I will be using is PHP with the APC code cache, Probably running Debian.

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Trouble Starting MySL Community Server on Windows 7

- by CodeAngel

I have installed Netbeans 7 on my Windows 7. In addition, the MySQL Community Server 5.6.12 is installed with the MSI installer on thesame 7 PC. The MySQL server is integrated with the Netbeans IDE. However , it is not possible to start or stop the MySQL server from the command prompt or the Netbeans IDE. I am only able to start or stop the server from the Windows 7 services tool. Also , it is difficult running SQL queries from the Netbeans IDE even though it shows there is connection with the MySQL server. I have added the my.ini file to the installed directory of the MySQL server , that is : C:\Program Files\MySQL\MySQL Server 5.6 below is the my.ini file : # For advice on how to change settings please see # http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html # *** DO NOT EDIT THIS FILE. It's a template which will be copied to the # *** default location during install, and will be replaced if you # *** upgrade to a newer version of MySQL. [mysqld] # Remove leading # and set to the amount of RAM for the most important data # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%. # innodb_buffer_pool_size = 128M # Remove leading # to turn on a very important data integrity option: logging # changes to the binary log between backups. # log_bin # These are commonly set, remove the # and set as required. # basedir = ..... # datadir = ..... port = 3306 # server_id = ..... # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES Any suggestion is welcomed.

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Building applications with WPF, MVVM and Prism(aka CAG)

- by skjagini

In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab). The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework. If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button, generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM), based on the interactions with in the three parties it should be called VVMM, MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code, samples and documentation on msdn. The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework? That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code. 1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock. Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml) is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper. namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e); (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher); Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show(); return shell; } } } Lets take a look into FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher); container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager()); . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType. With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator; public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’. The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion. <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />  </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history, existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface. From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file and you can also add module using code. Lets take a look into configuration file. <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface 5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load FareView and TotalView dynamically. To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService, idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel; namespace Framework.PresentationUtility.Navigation { public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; } void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command. When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly. And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } } public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory. Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case) and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO; namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } } TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System; namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } } Lets take a look into FareViewodel (Notifier) and how it raises the event. Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator; public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... } private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); } ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); } .... 7. MVVM through example In this section we are going to look into MVVM implementation through example. I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > .... <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/> <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" /> <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles <@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/> </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem to SelectedState. You might be wondering what are all these properties and how it is able to bind to them. The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel. Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section) namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } } public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } } public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } } public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } } public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } } public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } } public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } } public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } } public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } } } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value }); _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator; public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); } public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); } private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted)); SetTotalFare(Fares); } private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } .... } } TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare. Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View. I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.

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Capturing and Transforming ASP.NET Output with Response.Filter

- by Rick Strahl

During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT: ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if(IsGZipSupported()) { stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if(AcceptEncoding.Contains("deflate")) { Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "deflate"); } else { Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.AppendHeader("Content-Encoding", "gzip"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a> and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a> without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET

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SQL Server 2012 - AlwaysOn

- by Claus Jandausch

Ich war nicht nur irritiert, ich war sogar regelrecht schockiert - und für einen kurzen Moment sprachlos (was nur selten der Fall ist). Gerade eben hatte mich jemand gefragt "Wann Oracle denn etwas Vergleichbares wie AlwaysOn bieten würde - und ob überhaupt?" War ich hier im falschen Film gelandet? Ich konnte nicht anders, als meinen Unmut kundzutun und zu erklären, dass die Fragestellung normalerweise anders herum läuft. Zugegeben - es mag vielleicht strittige Punkte geben im Vergleich zwischen Oracle und SQL Server - bei denen nicht unbedingt immer Oracle die Nase vorn haben muss - aber das Thema Clustering für Hochverfügbarkeit (HA), Disaster Recovery (DR) und Skalierbarkeit gehört mit Sicherheit nicht dazu. Dieses Erlebnis hakte ich am Nachgang als Einzelfall ab, der so nie wieder vorkommen würde. Bis ich kurz darauf eines Besseren belehrt wurde und genau die selbe Frage erneut zu hören bekam. Diesmal sogar im Exadata-Umfeld und einem Oracle Stretch Cluster. Einmal ist keinmal, doch zweimal ist einmal zu viel... Getreu diesem alten Motto war mir klar, dass man das so nicht länger stehen lassen konnte. Ich habe keine Ahnung, wie die Microsoft Marketing Abteilung es geschafft hat, unter dem AlwaysOn Brading eine innovative Technologie vermuten zu lassen - aber sie hat ihren Job scheinbar gut gemacht. Doch abgesehen von einem guten Marketing, stellt sich natürlich die Frage, was wirklich dahinter steckt und wie sich das Ganze mit Oracle vergleichen lässt - und ob überhaupt? Damit wären wir wieder bei der ursprünglichen Frage angelangt. So viel zum Hintergrund dieses Blogbeitrags - von meiner Antwort handelt der restliche Blog. "Windows was the God ..." Um den wahren Unterschied zwischen Oracle und Microsoft verstehen zu können, muss man zunächst das bedeutendste Microsoft Dogma kennen. Es lässt sich schlicht und einfach auf den Punkt bringen: "Alles muss auf Windows basieren." Die Überschrift dieses Absatzes ist kein von mir erfundener Ausspruch, sondern ein Zitat. Konkret stammt es aus einem längeren Artikel von Kurt Eichenwald in der Vanity Fair aus dem August 2012. Er lautet Microsoft's Lost Decade und sei jedem ans Herz gelegt, der die "Microsoft-Maschinerie" unter Steve Ballmer und einige ihrer Kuriositäten besser verstehen möchte. "YOU TALKING TO ME?" Microsoft C.E.O. Steve Ballmer bei seiner Keynote auf der 2012 International Consumer Electronics Show in Las Vegas am 9. Januar Manche Dinge in diesem Artikel mögen überspitzt dargestellt erscheinen - sind sie aber nicht. Vieles davon kannte ich bereits aus eigener Erfahrung und kann es nur bestätigen. Anderes hat sich mir erst so richtig erschlossen. Insbesondere die folgenden Passagen führten zum Aha-Erlebnis: “Windows was the god—everything had to work with Windows,” said Stone... “Every little thing you want to write has to build off of Windows (or other existing roducts),” one software engineer said. “It can be very confusing, …” Ich habe immer schon darauf hingewiesen, dass in einem SQL Server Failover Cluster die Microsoft Datenbank eigentlich nichts Nenneswertes zum Geschehen beiträgt, sondern sich voll und ganz auf das Windows Betriebssystem verlässt. Deshalb muss man auch die Windows Server Enterprise Edition installieren, soll ein Failover Cluster für den SQL Server eingerichtet werden. Denn hier werden die Cluster Services geliefert - nicht mit dem SQL Server. Er ist nur lediglich ein weiteres Server Produkt, für das Windows in Ausfallszenarien genutzt werden kann - so wie Microsoft Exchange beispielsweise, oder Microsoft SharePoint, oder irgendein anderes Server Produkt das auf Windows gehostet wird. Auch Oracle kann damit genutzt werden. Das Stichwort lautet hier: Oracle Failsafe. Nur - warum sollte man das tun, wenn gleichzeitig eine überlegene Technologie wie die Oracle Real Application Clusters (RAC) zur Verfügung steht, die dann auch keine Windows Enterprise Edition voraussetzen, da Oracle die eigene Clusterware liefert. Welche darüber hinaus für kürzere Failover-Zeiten sorgt, da diese Cluster-Technologie Datenbank-integriert ist und sich nicht auf "Dritte" verlässt. Wenn man sich also schon keine technischen Vorteile mit einem SQL Server Failover Cluster erkauft, sondern zusätzlich noch versteckte Lizenzkosten durch die Lizenzierung der Windows Server Enterprise Edition einhandelt, warum hat Microsoft dann in den vergangenen Jahren seit SQL Server 2000 nicht ebenfalls an einer neuen und innovativen Lösung gearbeitet, die mit Oracle RAC mithalten kann? Entwickler hat Microsoft genügend? Am Geld kann es auch nicht liegen? Lesen Sie einfach noch einmal die beiden obenstehenden Zitate und sie werden den Grund verstehen. Anders lässt es sich ja auch gar nicht mehr erklären, dass AlwaysOn aus zwei unterschiedlichen Technologien besteht, die beide jedoch wiederum auf dem Windows Server Failover Clustering (WSFC) basieren. Denn daraus ergeben sich klare Nachteile - aber dazu später mehr. Um AlwaysOn zu verstehen, sollte man sich zunächst kurz in Erinnerung rufen, was Microsoft bisher an HA/DR (High Availability/Desaster Recovery) Lösungen für SQL Server zur Verfügung gestellt hat. Replikation Basiert auf logischer Replikation und Pubisher/Subscriber Architektur Transactional Replication Merge Replication Snapshot Replication Microsoft's Replikation ist vergleichbar mit Oracle GoldenGate. Oracle GoldenGate stellt jedoch die umfassendere Technologie dar und bietet High Performance. Log Shipping Microsoft's Log Shipping stellt eine einfache Technologie dar, die vergleichbar ist mit Oracle Managed Recovery in Oracle Version 7. Das Log Shipping besitzt folgende Merkmale: Transaction Log Backups werden von Primary nach Secondary/ies geschickt Einarbeitung (z.B. Restore) auf jedem Secondary individuell Optionale dritte Server Instanz (Monitor Server) für Überwachung und Alarm Log Restore Unterbrechung möglich für Read-Only Modus (Secondary) Keine Unterstützung von Automatic Failover Database Mirroring Microsoft's Database Mirroring wurde verfügbar mit SQL Server 2005, sah aus wie Oracle Data Guard in Oracle 9i, war funktional jedoch nicht so umfassend. Für ein HA/DR Paar besteht eine 1:1 Beziehung, um die produktive Datenbank (Principle DB) abzusichern. Auf der Standby Datenbank (Mirrored DB) werden alle Insert-, Update- und Delete-Operationen nachgezogen. Modi Synchron (High-Safety Modus) Asynchron (High-Performance Modus) Automatic Failover Unterstützt im High-Safety Modus (synchron) Witness Server vorausgesetzt Zur Frage der Kontinuität Es stellt sich die Frage, wie es um diesen Technologien nun im Zusammenhang mit SQL Server 2012 bestellt ist. Unter Fanfaren seinerzeit eingeführt, war Database Mirroring das erklärte Mittel der Wahl. Ich bin kein Produkt Manager bei Microsoft und kann hierzu nur meine Meinung äußern, aber zieht man den SQL AlwaysOn Team Blog heran, so sieht es nicht gut aus für das Database Mirroring - zumindest nicht langfristig. "Does AlwaysOn Availability Group replace Database Mirroring going forward?” “The short answer is we recommend that you migrate from the mirroring configuration or even mirroring and log shipping configuration to using Availability Group. Database Mirroring will still be available in the Denali release but will be phased out over subsequent releases. Log Shipping will continue to be available in future releases.” Damit wären wir endlich beim eigentlichen Thema angelangt. Was ist eine sogenannte Availability Group und was genau hat es mit der vielversprechend klingenden Bezeichnung AlwaysOn auf sich? SQL Server 2012 - AlwaysOn Zwei HA-Features verstekcne sich hinter dem “AlwaysOn”-Branding. Einmal das AlwaysOn Failover Clustering aka SQL Server Failover Cluster Instances (FCI) - zum Anderen die AlwaysOn Availability Groups. Failover Cluster Instances (FCI) Entspricht ungefähr dem Stretch Cluster Konzept von Oracle Setzt auf Windows Server Failover Clustering (WSFC) auf Bietet HA auf Instanz-Ebene AlwaysOn Availability Groups (Verfügbarkeitsgruppen) Ähnlich der Idee von Consistency Groups, wie in Storage-Level Replikations-Software von z.B. EMC SRDF Abhängigkeiten zu Windows Server Failover Clustering (WSFC) Bietet HA auf Datenbank-Ebene Hinweis: Verwechseln Sie nicht eine SQL Server Datenbank mit einer Oracle Datenbank. Und auch nicht eine Oracle Instanz mit einer SQL Server Instanz. Die gleichen Begriffe haben hier eine andere Bedeutung - nicht selten ein Grund, weshalb Oracle- und Microsoft DBAs schnell aneinander vorbei reden. Denken Sie bei einer SQL Server Datenbank eher an ein Oracle Schema, das kommt der Sache näher. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Wenn Sie die genauen Unterschiede kennen möchten, finden Sie eine detaillierte Beschreibung in meinem Buch "Oracle10g Release 2 für Windows und .NET", erhältich bei Lehmanns, Amazon, etc. Windows Server Failover Clustering (WSFC) Wie man sieht, basieren beide AlwaysOn Technologien wiederum auf dem Windows Server Failover Clustering (WSFC), um einerseits Hochverfügbarkeit auf Ebene der Instanz zu gewährleisten und andererseits auf der Datenbank-Ebene. Deshalb nun eine kurze Beschreibung der WSFC. Die WSFC sind ein mit dem Windows Betriebssystem geliefertes Infrastruktur-Feature, um HA für Server Anwendungen, wie Microsoft Exchange, SharePoint, SQL Server, etc. zu bieten. So wie jeder andere Cluster, besteht ein WSFC Cluster aus einer Gruppe unabhängiger Server, die zusammenarbeiten, um die Verfügbarkeit einer Applikation oder eines Service zu erhöhen. Falls ein Cluster-Knoten oder -Service ausfällt, kann der auf diesem Knoten bisher gehostete Service automatisch oder manuell auf einen anderen im Cluster verfügbaren Knoten transferriert werden - was allgemein als Failover bekannt ist. Unter SQL Server 2012 verwenden sowohl die AlwaysOn Avalability Groups, als auch die AlwaysOn Failover Cluster Instances die WSFC als Plattformtechnologie, um Komponenten als WSFC Cluster-Ressourcen zu registrieren. Verwandte Ressourcen werden in eine Ressource Group zusammengefasst, die in Abhängigkeit zu anderen WSFC Cluster-Ressourcen gebracht werden kann. Der WSFC Cluster Service kann jetzt die Notwendigkeit zum Neustart der SQL Server Instanz erfassen oder einen automatischen Failover zu einem anderen Server-Knoten im WSFC Cluster auslösen. Failover Cluster Instances (FCI) Eine SQL Server Failover Cluster Instanz (FCI) ist eine einzelne SQL Server Instanz, die in einem Failover Cluster betrieben wird, der aus mehreren Windows Server Failover Clustering (WSFC) Knoten besteht und so HA (High Availability) auf Ebene der Instanz bietet. Unter Verwendung von Multi-Subnet FCI kann auch Remote DR (Disaster Recovery) unterstützt werden. Eine weitere Option für Remote DR besteht darin, eine unter FCI gehostete Datenbank in einer Availability Group zu betreiben. Hierzu später mehr. FCI und WSFC Basis FCI, das für lokale Hochverfügbarkeit der Instanzen genutzt wird, ähnelt der veralteten Architektur eines kalten Cluster (Aktiv-Passiv). Unter SQL Server 2008 wurde diese Technologie SQL Server 2008 Failover Clustering genannt. Sie nutzte den Windows Server Failover Cluster. In SQL Server 2012 hat Microsoft diese Basistechnologie unter der Bezeichnung AlwaysOn zusammengefasst. Es handelt sich aber nach wie vor um die klassische Aktiv-Passiv-Konfiguration. Der Ablauf im Failover-Fall ist wie folgt: Solange kein Hardware-oder System-Fehler auftritt, werden alle Dirty Pages im Buffer Cache auf Platte geschrieben Alle entsprechenden SQL Server Services (Dienste) in der Ressource Gruppe werden auf dem aktiven Knoten gestoppt Die Ownership der Ressource Gruppe wird auf einen anderen Knoten der FCI transferriert Der neue Owner (Besitzer) der Ressource Gruppe startet seine SQL Server Services (Dienste) Die Connection-Anforderungen einer Client-Applikation werden automatisch auf den neuen aktiven Knoten mit dem selben Virtuellen Network Namen (VNN) umgeleitet Abhängig vom Zeitpunkt des letzten Checkpoints, kann die Anzahl der Dirty Pages im Buffer Cache, die noch auf Platte geschrieben werden müssen, zu unvorhersehbar langen Failover-Zeiten führen. Um diese Anzahl zu drosseln, besitzt der SQL Server 2012 eine neue Fähigkeit, die Indirect Checkpoints genannt wird. Indirect Checkpoints ähnelt dem Fast-Start MTTR Target Feature der Oracle Datenbank, das bereits mit Oracle9i verfügbar war. SQL Server Multi-Subnet Clustering Ein SQL Server Multi-Subnet Failover Cluster entspricht vom Konzept her einem Oracle RAC Stretch Cluster. Doch dies ist nur auf den ersten Blick der Fall. Im Gegensatz zu RAC ist in einem lokalen SQL Server Failover Cluster jeweils nur ein Knoten aktiv für eine Datenbank. Für die Datenreplikation zwischen geografisch entfernten Sites verlässt sich Microsoft auf 3rd Party Lösungen für das Storage Mirroring. Die Verbesserung dieses Szenario mit einer SQL Server 2012 Implementierung besteht schlicht darin, dass eine VLAN-Konfiguration (Virtual Local Area Network) nun nicht mehr benötigt wird, so wie dies bisher der Fall war. Das folgende Diagramm stellt dar, wie der Ablauf mit SQL Server 2012 gehandhabt wird. In Site A und Site B wird HA jeweils durch einen lokalen Aktiv-Passiv-Cluster sichergestellt. Besondere Aufmerksamkeit muss hier der Konfiguration und dem Tuning geschenkt werden, da ansonsten völlig inakzeptable Failover-Zeiten resultieren. Dies liegt darin begründet, weil die Downtime auf Client-Seite nun nicht mehr nur von der reinen Failover-Zeit abhängt, sondern zusätzlich von der Dauer der DNS Replikation zwischen den DNS Servern. (Rufen Sie sich in Erinnerung, dass wir gerade von Multi-Subnet Clustering sprechen). Außerdem ist zu berücksichtigen, wie schnell die Clients die aktualisierten DNS Informationen abfragen. Spezielle Konfigurationen für Node Heartbeat, HostRecordTTL (Host Record Time-to-Live) und Intersite Replication Frequeny für Active Directory Sites und Services werden notwendig. Default TTL für Windows Server 2008 R2: 20 Minuten Empfohlene Einstellung: 1 Minute DNS Update Replication Frequency in Windows Umgebung: 180 Minuten Empfohlene Einstellung: 15 Minuten (minimaler Wert) Betrachtet man diese Werte, muss man feststellen, dass selbst eine optimale Konfiguration die rigiden SLAs (Service Level Agreements) heutiger geschäftskritischer Anwendungen für HA und DR nicht erfüllen kann. Denn dies impliziert eine auf der Client-Seite erlebte Failover-Zeit von insgesamt 16 Minuten. Hierzu ein Auszug aus der SQL Server 2012 Online Dokumentation: Cons: If a cross-subnet failover occurs, the client recovery time could be 15 minutes or longer, depending on your HostRecordTTL setting and the setting of your cross-site DNS/AD replication schedule. Wir sind hier an einem Punkt unserer Überlegungen angelangt, an dem sich erklärt, weshalb ich zuvor das "Windows was the God ..." Zitat verwendet habe. Die unbedingte Abhängigkeit zu Windows wird zunehmend zum Problem, da sie die Komplexität einer Microsoft-basierenden Lösung erhöht, anstelle sie zu reduzieren. Und Komplexität ist das Letzte, was sich CIOs heutzutage wünschen. Zur Ehrenrettung des SQL Server 2012 und AlwaysOn muss man sagen, dass derart lange Failover-Zeiten kein unbedingtes "Muss" darstellen, sondern ein "Kann". Doch auch ein "Kann" kann im unpassenden Moment unvorhersehbare und kostspielige Folgen haben. Die Unabsehbarkeit ist wiederum Ursache vieler an der Implementierung beteiligten Komponenten und deren Abhängigkeiten, wie beispielsweise drei Cluster-Lösungen (zwei von Microsoft, eine 3rd Party Lösung). Wie man die Sache auch dreht und wendet, kommt man an diesem Fakt also nicht vorbei - ganz unabhängig von der Dauer einer Downtime oder Failover-Zeiten. Im Gegensatz zu AlwaysOn und der hier vorgestellten Version eines Stretch-Clusters, vermeidet eine entsprechende Oracle Implementierung eine derartige Komplexität, hervorgerufen duch multiple Abhängigkeiten. Den Unterschied machen Datenbank-integrierte Mechanismen, wie Fast Application Notification (FAN) und Fast Connection Failover (FCF). Für Oracle MAA Konfigurationen (Maximum Availability Architecture) sind Inter-Site Failover-Zeiten im Bereich von Sekunden keine Seltenheit. Wenn Sie dem Link zur Oracle MAA folgen, finden Sie außerdem eine Reihe an Customer Case Studies. Auch dies ist ein wichtiges Unterscheidungsmerkmal zu AlwaysOn, denn die Oracle Technologie hat sich bereits zigfach in höchst kritischen Umgebungen bewährt. Availability Groups (Verfügbarkeitsgruppen) Die sogenannten Availability Groups (Verfügbarkeitsgruppen) sind - neben FCI - der weitere Baustein von AlwaysOn. Hinweis: Bevor wir uns näher damit beschäftigen, sollten Sie sich noch einmal ins Gedächtnis rufen, dass eine SQL Server Datenbank nicht die gleiche Bedeutung besitzt, wie eine Oracle Datenbank, sondern eher einem Oracle Schema entspricht. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Eine Verfügbarkeitsgruppe setzt sich zusammen aus einem Set mehrerer Benutzer-Datenbanken, die im Falle eines Failover gemeinsam als Gruppe behandelt werden. Eine Verfügbarkeitsgruppe unterstützt ein Set an primären Datenbanken (primäres Replikat) und einem bis vier Sets von entsprechenden sekundären Datenbanken (sekundäre Replikate). Es können jedoch nicht alle SQL Server Datenbanken einer AlwaysOn Verfügbarkeitsgruppe zugeordnet werden. Der SQL Server Spezialist Michael Otey zählt in seinem SQL Server Pro Artikel folgende Anforderungen auf: Verfügbarkeitsgruppen müssen mit Benutzer-Datenbanken erstellt werden. System-Datenbanken können nicht verwendet werden Die Datenbanken müssen sich im Read-Write Modus befinden. Read-Only Datenbanken werden nicht unterstützt Die Datenbanken in einer Verfügbarkeitsgruppe müssen Multiuser Datenbanken sein Sie dürfen nicht das AUTO_CLOSE Feature verwenden Sie müssen das Full Recovery Modell nutzen und es muss ein vollständiges Backup vorhanden sein Eine gegebene Datenbank kann sich nur in einer einzigen Verfügbarkeitsgruppe befinden und diese Datenbank düerfen nicht für Database Mirroring konfiguriert sein Microsoft empfiehl außerdem, dass der Verzeichnispfad einer Datenbank auf dem primären und sekundären Server identisch sein sollte Wie man sieht, eignen sich Verfügbarkeitsgruppen nicht, um HA und DR vollständig abzubilden. Die Unterscheidung zwischen der Instanzen-Ebene (FCI) und Datenbank-Ebene (Availability Groups) ist von hoher Bedeutung. Vor kurzem wurde mir gesagt, dass man mit den Verfügbarkeitsgruppen auf Shared Storage verzichten könne und dadurch Kosten spart. So weit so gut ... Man kann natürlich eine Installation rein mit Verfügbarkeitsgruppen und ohne FCI durchführen - aber man sollte sich dann darüber bewusst sein, was man dadurch alles nicht abgesichert hat - und dies wiederum für Desaster Recovery (DR) und SLAs (Service Level Agreements) bedeutet. Kurzum, um die Kombination aus beiden AlwaysOn Produkten und der damit verbundene Komplexität kommt man wohl in der Praxis nicht herum. Availability Groups und WSFC AlwaysOn hängt von Windows Server Failover Clustering (WSFC) ab, um die aktuellen Rollen der Verfügbarkeitsreplikate einer Verfügbarkeitsgruppe zu überwachen und zu verwalten, und darüber zu entscheiden, wie ein Failover-Ereignis die Verfügbarkeitsreplikate betrifft. Das folgende Diagramm zeigt de Beziehung zwischen Verfügbarkeitsgruppen und WSFC: Der Verfügbarkeitsmodus ist eine Eigenschaft jedes Verfügbarkeitsreplikats. Synychron und Asynchron können also gemischt werden: Availability Modus (Verfügbarkeitsmodus) Asynchroner Commit-Modus Primäres replikat schließt Transaktionen ohne Warten auf Sekundäres Synchroner Commit-Modus Primäres Replikat wartet auf Commit von sekundärem Replikat Failover Typen Automatic Manual Forced (mit möglichem Datenverlust) Synchroner Commit-Modus Geplanter, manueller Failover ohne Datenverlust Automatischer Failover ohne Datenverlust Asynchroner Commit-Modus Nur Forced, manueller Failover mit möglichem Datenverlust Der SQL Server kennt keinen separaten Switchover Begriff wie in Oracle Data Guard. Für SQL Server werden alle Role Transitions als Failover bezeichnet. Tatsächlich unterstützt der SQL Server keinen Switchover für asynchrone Verbindungen. Es gibt nur die Form des Forced Failover mit möglichem Datenverlust. Eine ähnliche Fähigkeit wie der Switchover unter Oracle Data Guard ist so nicht gegeben. SQL Sever FCI mit Availability Groups (Verfügbarkeitsgruppen) Neben den Verfügbarkeitsgruppen kann eine zweite Failover-Ebene eingerichtet werden, indem SQL Server FCI (auf Shared Storage) mit WSFC implementiert wird. Ein Verfügbarkeitesreplikat kann dann auf einer Standalone Instanz gehostet werden, oder einer FCI Instanz. Zum Verständnis: Die Verfügbarkeitsgruppen selbst benötigen kein Shared Storage. Diese Kombination kann verwendet werden für lokale HA auf Ebene der Instanz und DR auf Datenbank-Ebene durch Verfügbarkeitsgruppen. Das folgende Diagramm zeigt dieses Szenario: Achtung! Hier handelt es sich nicht um ein Pendant zu Oracle RAC plus Data Guard, auch wenn das Bild diesen Eindruck vielleicht vermitteln mag - denn alle sekundären Knoten im FCI sind rein passiv. Es existiert außerdem eine weitere und ernsthafte Einschränkung: SQL Server Failover Cluster Instanzen (FCI) unterstützen nicht das automatische AlwaysOn Failover für Verfügbarkeitsgruppen. Jedes unter FCI gehostete Verfügbarkeitsreplikat kann nur für manuelles Failover konfiguriert werden. Lesbare Sekundäre Replikate Ein oder mehrere Verfügbarkeitsreplikate in einer Verfügbarkeitsgruppe können für den lesenden Zugriff konfiguriert werden, wenn sie als sekundäres Replikat laufen. Dies ähnelt Oracle Active Data Guard, jedoch gibt es Einschränkungen. Alle Abfragen gegen die sekundäre Datenbank werden automatisch auf das Snapshot Isolation Level abgebildet. Es handelt sich dabei um eine Versionierung der Rows. Microsoft versuchte hiermit die Oracle MVRC (Multi Version Read Consistency) nachzustellen. Tatsächlich muss man die SQL Server Snapshot Isolation eher mit Oracle Flashback vergleichen. Bei der Implementierung des Snapshot Isolation Levels handelt sich um ein nachträglich aufgesetztes Feature und nicht um einen inhärenten Teil des Datenbank-Kernels, wie im Falle Oracle. (Ich werde hierzu in Kürze einen weiteren Blogbeitrag verfassen, wenn ich mich mit der neuen SQL Server 2012 Core Lizenzierung beschäftige.) Für die Praxis entstehen aus der Abbildung auf das Snapshot Isolation Level ernsthafte Restriktionen, derer man sich für den Betrieb in der Praxis bereits vorab bewusst sein sollte: Sollte auf der primären Datenbank eine aktive Transaktion zu dem Zeitpunkt existieren, wenn ein lesbares sekundäres Replikat in die Verfügbarkeitsgruppe aufgenommen wird, werden die Row-Versionen auf der korrespondierenden sekundären Datenbank nicht sofort vollständig verfügbar sein. Eine aktive Transaktion auf dem primären Replikat muss zuerst abgeschlossen (Commit oder Rollback) und dieser Transaktions-Record auf dem sekundären Replikat verarbeitet werden. Bis dahin ist das Isolation Level Mapping auf der sekundären Datenbank unvollständig und Abfragen sind temporär geblockt. Microsoft sagt dazu: "This is needed to guarantee that row versions are available on the secondary replica before executing the query under snapshot isolation as all isolation levels are implicitly mapped to snapshot isolation." (SQL Storage Engine Blog: AlwaysOn: I just enabled Readable Secondary but my query is blocked?) Grundlegend bedeutet dies, dass ein aktives lesbares Replikat nicht in die Verfügbarkeitsgruppe aufgenommen werden kann, ohne das primäre Replikat vorübergehend stillzulegen. Da Leseoperationen auf das Snapshot Isolation Transaction Level abgebildet werden, kann die Bereinigung von Ghost Records auf dem primären Replikat durch Transaktionen auf einem oder mehreren sekundären Replikaten geblockt werden - z.B. durch eine lang laufende Abfrage auf dem sekundären Replikat. Diese Bereinigung wird auch blockiert, wenn die Verbindung zum sekundären Replikat abbricht oder der Datenaustausch unterbrochen wird. Auch die Log Truncation wird in diesem Zustant verhindert. Wenn dieser Zustand längere Zeit anhält, empfiehlt Microsoft das sekundäre Replikat aus der Verfügbarkeitsgruppe herauszunehmen - was ein ernsthaftes Downtime-Problem darstellt. Die Read-Only Workload auf den sekundären Replikaten kann eingehende DDL Änderungen blockieren. Obwohl die Leseoperationen aufgrund der Row-Versionierung keine Shared Locks halten, führen diese Operatioen zu Sch-S Locks (Schemastabilitätssperren). DDL-Änderungen durch Redo-Operationen können dadurch blockiert werden. Falls DDL aufgrund konkurrierender Lese-Workload blockiert wird und der Schwellenwert für 'Recovery Interval' (eine SQL Server Konfigurationsoption) überschritten wird, generiert der SQL Server das Ereignis sqlserver.lock_redo_blocked, welches Microsoft zum Kill der blockierenden Leser empfiehlt. Auf die Verfügbarkeit der Anwendung wird hierbei keinerlei Rücksicht genommen. Keine dieser Einschränkungen existiert mit Oracle Active Data Guard. Backups auf sekundären Replikaten Über die sekundären Replikate können Backups (BACKUP DATABASE via Transact-SQL) nur als copy-only Backups einer vollständigen Datenbank, Dateien und Dateigruppen erstellt werden. Das Erstellen inkrementeller Backups ist nicht unterstützt, was ein ernsthafter Rückstand ist gegenüber der Backup-Unterstützung physikalischer Standbys unter Oracle Data Guard. Hinweis: Ein möglicher Workaround via Snapshots, bleibt ein Workaround. Eine weitere Einschränkung dieses Features gegenüber Oracle Data Guard besteht darin, dass das Backup eines sekundären Replikats nicht ausgeführt werden kann, wenn es nicht mit dem primären Replikat kommunizieren kann. Darüber hinaus muss das sekundäre Replikat synchronisiert sein oder sich in der Synchronisation befinden, um das Beackup auf dem sekundären Replikat erstellen zu können. Vergleich von Microsoft AlwaysOn mit der Oracle MAA Ich komme wieder zurück auf die Eingangs erwähnte, mehrfach an mich gestellte Frage "Wann denn - und ob überhaupt - Oracle etwas Vergleichbares wie AlwaysOn bieten würde?" und meine damit verbundene (kurze) Irritation. Wenn Sie diesen Blogbeitrag bis hierher gelesen haben, dann kennen Sie jetzt meine darauf gegebene Antwort. Der eine oder andere Punkt traf dabei nicht immer auf Jeden zu, was auch nicht der tiefere Sinn und Zweck meiner Antwort war. Wenn beispielsweise kein Multi-Subnet mit im Spiel ist, sind alle diesbezüglichen Kritikpunkte zunächst obsolet. Was aber nicht bedeutet, dass sie nicht bereits morgen schon wieder zum Thema werden könnten (Sag niemals "Nie"). In manch anderes Fettnäpfchen tritt man wiederum nicht unbedingt in einer Testumgebung, sondern erst im laufenden Betrieb. Erst recht nicht dann, wenn man sich potenzieller Probleme nicht bewusst ist und keine dedizierten Tests startet. Und wer AlwaysOn erfolgreich positionieren möchte, wird auch gar kein Interesse daran haben, auf mögliche Schwachstellen und den besagten Teufel im Detail aufmerksam zu machen. Das ist keine Unterstellung - es ist nur menschlich. Außerdem ist es verständlich, dass man sich in erster Linie darauf konzentriert "was geht" und "was gut läuft", anstelle auf das "was zu Problemen führen kann" oder "nicht funktioniert". Wer will schon der Miesepeter sein? Für mich selbst gesprochen, kann ich nur sagen, dass ich lieber vorab von allen möglichen Einschränkungen wissen möchte, anstelle sie dann nach einer kurzen Zeit der heilen Welt schmerzhaft am eigenen Leib erfahren zu müssen. Ich bin davon überzeugt, dass es Ihnen nicht anders geht. Nachfolgend deshalb eine Zusammenfassung all jener Punkte, die ich im Vergleich zur Oracle MAA (Maximum Availability Architecture) als unbedingt Erwähnenswert betrachte, falls man eine Evaluierung von Microsoft AlwaysOn in Betracht zieht. 1. AlwaysOn ist eine komplexe Technologie Der SQL Server AlwaysOn Stack ist zusammengesetzt aus drei verschiedenen Technlogien: Windows Server Failover Clustering (WSFC) SQL Server Failover Cluster Instances (FCI) SQL Server Availability Groups (Verfügbarkeitsgruppen) Man kann eine derartige Lösung nicht als nahtlos bezeichnen, wofür auch die vielen von Microsoft dargestellten Einschränkungen sprechen. Während sich frühere SQL Server Versionen in Richtung eigener HA/DR Technologien entwickelten (wie Database Mirroring), empfiehlt Microsoft nun die Migration. Doch weshalb dieser Schwenk? Er führt nicht zu einem konsisten und robusten Angebot an HA/DR Technologie für geschäftskritische Umgebungen. Liegt die Antwort in meiner These begründet, nach der "Windows was the God ..." noch immer gilt und man die Nachteile der allzu engen Kopplung mit Windows nicht sehen möchte? Entscheiden Sie selbst ... 2. Failover Cluster Instanzen - Kein RAC-Pendant Die SQL Server und Windows Server Clustering Technologie basiert noch immer auf dem veralteten Aktiv-Passiv Modell und führt zu einer Verschwendung von Systemressourcen. In einer Betrachtung von lediglich zwei Knoten erschließt sich auf Anhieb noch nicht der volle Mehrwert eines Aktiv-Aktiv Clusters (wie den Real Application Clusters), wie er von Oracle bereits vor zehn Jahren entwickelt wurde. Doch kennt man die Vorzüge der Skalierbarkeit durch einfaches Hinzufügen weiterer Cluster-Knoten, die dann alle gemeinsam als ein einziges logisches System zusammenarbeiten, versteht man was hinter dem Motto "Pay-as-you-Grow" steckt. In einem Aktiv-Aktiv Cluster geht es zwar auch um Hochverfügbarkeit - und ein Failover erfolgt zudem schneller, als in einem Aktiv-Passiv Modell - aber es geht eben nicht nur darum. An dieser Stelle sei darauf hingewiesen, dass die Oracle 11g Standard Edition bereits die Nutzung von Oracle RAC bis zu vier Sockets kostenfrei beinhaltet. Möchten Sie dazu Windows nutzen, benötigen Sie keine Windows Server Enterprise Edition, da Oracle 11g die eigene Clusterware liefert. Sie kommen in den Genuss von Hochverfügbarkeit und Skalierbarkeit und können dazu die günstigere Windows Server Standard Edition nutzen. 3. SQL Server Multi-Subnet Clustering - Abhängigkeit zu 3rd Party Storage Mirroring Die SQL Server Multi-Subnet Clustering Architektur unterstützt den Aufbau eines Stretch Clusters, basiert dabei aber auf dem Aktiv-Passiv Modell. Das eigentlich Problematische ist jedoch, dass man sich zur Absicherung der Datenbank auf 3rd Party Storage Mirroring Technologie verlässt, ohne Integration zwischen dem Windows Server Failover Clustering (WSFC) und der darunterliegenden Mirroring Technologie. Wenn nun im Cluster ein Failover auf Instanzen-Ebene erfolgt, existiert keine Koordination mit einem möglichen Failover auf Ebene des Storage-Array. 4. Availability Groups (Verfügbarkeitsgruppen) - Vier, oder doch nur Zwei? Ein primäres Replikat erlaubt bis zu vier sekundäre Replikate innerhalb einer Verfügbarkeitsgruppe, jedoch nur zwei im Synchronen Commit Modus. Während dies zwar einen Vorteil gegenüber dem stringenten 1:1 Modell unter Database Mirroring darstellt, fällt der SQL Server 2012 damit immer noch weiter zurück hinter Oracle Data Guard mit bis zu 30 direkten Stanbdy Zielen - und vielen weiteren durch kaskadierende Ziele möglichen. Damit eignet sich Oracle Active Data Guard auch für die Bereitstellung einer Reader-Farm Skalierbarkeit für Internet-basierende Unternehmen. Mit AwaysOn Verfügbarkeitsgruppen ist dies nicht möglich. 5. Availability Groups (Verfügbarkeitsgruppen) - kein asynchrones Switchover Die Technologie der Verfügbarkeitsgruppen wird auch als geeignetes Mittel für administrative Aufgaben positioniert - wie Upgrades oder Wartungsarbeiten. Man muss sich jedoch einem gravierendem Defizit bewusst sein: Im asynchronen Verfügbarkeitsmodus besteht die einzige Möglichkeit für Role Transition im Forced Failover mit Datenverlust! Um den Verlust von Daten durch geplante Wartungsarbeiten zu vermeiden, muss man den synchronen Verfügbarkeitsmodus konfigurieren, was jedoch ernstzunehmende Auswirkungen auf WAN Deployments nach sich zieht. Spinnt man diesen Gedanken zu Ende, kommt man zu dem Schluss, dass die Technologie der Verfügbarkeitsgruppen für geplante Wartungsarbeiten in einem derartigen Umfeld nicht effektiv genutzt werden kann. 6. Automatisches Failover - Nicht immer möglich Sowohl die SQL Server FCI, als auch Verfügbarkeitsgruppen unterstützen automatisches Failover. Möchte man diese jedoch kombinieren, wird das Ergebnis kein automatisches Failover sein. Denn ihr Zusammentreffen im Failover-Fall führt zu Race Conditions (Wettlaufsituationen), weshalb diese Konfiguration nicht länger das automatische Failover zu einem Replikat in einer Verfügbarkeitsgruppe erlaubt. Auch hier bestätigt sich wieder die tiefere Problematik von AlwaysOn, mit einer Zusammensetzung aus unterschiedlichen Technologien und der Abhängigkeit zu Windows. 7. Problematische RTO (Recovery Time Objective) Microsoft postioniert die SQL Server Multi-Subnet Clustering Architektur als brauchbare HA/DR Architektur. Bedenkt man jedoch die Problematik im Zusammenhang mit DNS Replikation und den möglichen langen Wartezeiten auf Client-Seite von bis zu 16 Minuten, sind strenge RTO Anforderungen (Recovery Time Objectives) nicht erfüllbar. Im Gegensatz zu Oracle besitzt der SQL Server keine Datenbank-integrierten Technologien, wie Oracle Fast Application Notification (FAN) oder Oracle Fast Connection Failover (FCF). 8. Problematische RPO (Recovery Point Objective) SQL Server ermöglicht Forced Failover (erzwungenes Failover), bietet jedoch keine Möglichkeit zur automatischen Übertragung der letzten Datenbits von einem alten zu einem neuen primären Replikat, wenn der Verfügbarkeitsmodus asynchron war. Oracle Data Guard hingegen bietet diese Unterstützung durch das Flush Redo Feature. Dies sichert "Zero Data Loss" und beste RPO auch in erzwungenen Failover-Situationen. 9. Lesbare Sekundäre Replikate mit Einschränkungen Aufgrund des Snapshot Isolation Transaction Level für lesbare sekundäre Replikate, besitzen diese Einschränkungen mit Auswirkung auf die primäre Datenbank. Die Bereinigung von Ghost Records auf der primären Datenbank, wird beeinflusst von lang laufenden Abfragen auf der lesabaren sekundären Datenbank. Die lesbare sekundäre Datenbank kann nicht in die Verfügbarkeitsgruppe aufgenommen werden, wenn es aktive Transaktionen auf der primären Datenbank gibt. Zusätzlich können DLL Änderungen auf der primären Datenbank durch Abfragen auf der sekundären blockiert werden. Und imkrementelle Backups werden hier nicht unterstützt. Keine dieser Restriktionen existiert unter Oracle Data Guard.

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Why should you choose Oracle WebLogic 12c instead of JBoss EAP 6?

- by Ricardo Ferreira

In this post, I will cover some technical differences between Oracle WebLogic 12c and JBoss EAP 6, which was released a couple days ago from Red Hat. This article claims to help you in the evaluation of key points that you should consider when choosing for an Java EE application server. In the following sections, I will present to you some important aspects that most customers ask us when they are seriously evaluating for an middleware infrastructure, specially if you are considering JBoss for some reason. I would suggest that you keep the following question in mind while you are reading the points: "Why should I choose JBoss instead of WebLogic?" 1) Multi Datacenter Deployment and Clustering - D/R ("Disaster & Recovery") architecture support is embedded on the WebLogic Server 12c product. JBoss EAP 6 on the other hand has no direct D/R support included, Red Hat relies on third-part tools with higher prices. When you consider a middleware solution to host your business critical application, you should worry with every architectural aspect that are related with the solution. Fail-over support is one little aspect of a truly reliable solution. If you do not worry about D/R, your solution will not be reliable. Having said that, with Red Hat and JBoss EAP 6, you have this extra cost that will increase considerably the total cost of ownership of the solution. As we commonly hear from analysts, open-source are not so cheaper when you start seeing the big picture. - WebLogic Server 12c supports advanced LAN clustering, detection of death servers and have a common alert framework. JBoss EAP 6 on the other hand has limited LAN clustering support with no server death detection. They do not generate any alerts when servers goes down (only if you buy JBoss ON which is a separated technology, but until now does not support JBoss EAP 6) and manual intervention are required when servers goes down. In most cases, admin people must rely on "kill -9", "tail -f someFile.log" and "ps ax | grep java" commands to manage failures and clustering anomalies. - WebLogic Server 12c supports the concept of Node Manager, which is a separated process that runs on the physical | virtual servers that allows extend the administration of the cluster to WebLogic managed servers that are often distributed across multiple machines and geographic locations. JBoss EAP 6 on the other hand has no equivalent technology. Whole server instances must be managed individually. - WebLogic Server 12c Node Manager supports Coherence to boost performance when managing servers. JBoss EAP 6 on the other hand has no similar technology. There is no way to coordinate JBoss and infiniband instances provided by JBoss using high throughput and low latency protocols like InfiniBand. The Node Manager feature also allows another very important feature that JBoss EAP lacks: secure the administration. When using WebLogic Node Manager, all the administration tasks are sent to the managed servers in a secure tunel protected by a certificate, which means that the transport layer that separates the WebLogic administration console from the managed servers are secured by SSL. - WebLogic Server 12c are now integrated with OTD ("Oracle Traffic Director") which is a web server technology derived from the former Sun iPlanet Web Server. This software complements the web server support offered by OHS ("Oracle HTTP Server"). Using OTD, WebLogic instances are load-balanced by a high powerful software that knows how to handle SDP ("Socket Direct Protocol") over InfiniBand, which boost performance when used with engineered systems technologies like Oracle Exalogic Elastic Cloud. JBoss EAP 6 on the other hand only offers support to Apache Web Server with custom modules created to deal with JBoss clusters, but only across standard TCP/IP networks. 2) Application and Runtime Diagnostics - WebLogic Server 12c have diagnostics capabilities embedded on the server called WLDF ("WebLogic Diagnostic Framework") so there is no need to rely on third-part tools. JBoss EAP 6 on the other hand has no diagnostics capabilities. Their only diagnostics tool is the log generated by the application server. Admin people are encouraged to analyse thousands of log lines to find out what is going on. - WebLogic Server 12c complement WLDF with JRockit MC ("Mission Control"), which provides to administrators and developers a complete insight about the JVM performance, behavior and possible bottlenecks. WebLogic Server 12c also have an classloader analysis tool embedded, and even a log analyzer tool that enables administrators and developers to view logs of multiple servers at the same time. JBoss EAP 6 on the other hand relies on third-part tools to do something similar. Again, only log searching are offered to find out whats going on. - WebLogic Server 12c offers end-to-end traceability and monitoring available through Oracle EM ("Enterprise Manager"), including monitoring of business transactions that flows through web servers, ESBs, application servers and database servers, all of this with high deep JVM analysis and diagnostics. JBoss EAP 6 on the other hand, even using JBoss ON ("Operations Network"), which is a separated technology, does not support those features. Red Hat relies on third-part tools to provide direct Oracle database traceability across JVMs. One of those tools are Oracle EM for non-Oracle middleware that manage JBoss, Tomcat, Websphere and IIS transparently. - WebLogic Server 12c with their JRockit support offers a tool called JRockit Flight Recorder, which can give developers a complete visibility of a certain period of application production monitoring with zero extra overhead. This automatic recording allows you to deep analyse threads latency, memory leaks, thread contention, resource utilization, stack overflow damages and GC ("Garbage Collection") cycles, to observe in real time stop-the-world phenomenons, generational, reference count and parallel collects and mutator threads analysis. JBoss EAP 6 don't even dream to support something similar, even because they don't have their own JVM. 3) Application Server Administration - WebLogic Server 12c offers a complete administration console complemented with scripting and macro-like recording capabilities. A single WebLogic console can managed up to hundreds of WebLogic servers belonging to the same domain. JBoss EAP 6 on the other hand has a limited console and provides a XML centric administration. JBoss, after ten years, started the development of a rudimentary centralized administration that still leave a lot of administration tasks aside, so admin people and developers must touch scripts and XML configuration files for most advanced and even simple administration tasks. This lead applications to error prone and risky deployments. Even using JBoss ON, JBoss EAP are not able to offer decent administration features for admin people which must be high skilled in JBoss internal architecture and its managing capabilities. - Oracle EM is available to manage multiple domains, databases, application servers, operating systems and virtualization, with a complete end-to-end visibility. JBoss ON does not provide management capabilities across the complete architecture, only basic monitoring. Even deployment must be done aside JBoss ON which does no integrate well with others softwares than JBoss. Until now, JBoss ON does not supports JBoss EAP 6, so even their minimal support for JBoss are not available for JBoss EAP 6 leaving customers uncovered and subject to high skilled JBoss admin people. - WebLogic Server 12c has the same administration model whatever is the topology selected by the customer. JBoss EAP 6 on the other hand differentiates between two operational models: standalone-mode and domain-mode, that are not consistent with each other. Depending on the mode used, the administration skill is different. - WebLogic Server 12c has no point-of-failures processes, and it does not need to define any specialized server. Domain model in WebLogic is available for years (at least ten years or more) and is production proven. JBoss EAP 6 on the other hand needs special processes to garantee JBoss integrity, the PC ("Process-Controller") and the HC ("Host-Controller"). Different from WebLogic, the domain model in JBoss is quite new (one year at tops) of maturity, and need to mature considerably until start doing things like WebLogic domain model does. - WebLogic Server 12c supports parallel deployment model which enables some artifacts being deployed at the same time. JBoss EAP 6 on the other hand does not have any similar feature. Every deployment are done atomically in the containers. This means that if you have a huge EAR (an EAR of 120 MB of size for instance) and deploy onto JBoss EAP 6, this EAR will take some minutes in order to starting accept thread requests. The same EAR deployed onto WebLogic Server 12c will reduce the deployment time at least in 2X compared to JBoss. 4) Support and Upgrades - WebLogic Server 12c has patch management available. JBoss EAP 6 on the other hand has no patch management available, each JBoss EAP instance should be patched manually. To achieve such feature, you need to buy a separated technology called JBoss ON ("Operations Network") that manage this type of stuff. But until now, JBoss ON does not support JBoss EAP 6 so, in practice, JBoss EAP 6 does not have this feature. - WebLogic Server 12c supports previuous WebLogic domains without any reconfiguration since its kernel is robust and mature since its creation in 1995. JBoss EAP 6 on the other hand has a proven lack of supportability between JBoss AS 4, 5, 6 and 7. Different kernels and messaging engines were implemented in JBoss stack in the last five years reveling their incapacity to create a well architected and proven middleware technology. - WebLogic Server 12c has patch prescription based on customer configuration. JBoss EAP 6 on the other hand has no such capability. People need to create ticket supports and have their installations revised by Red Hat support guys to gain some patch prescription from them. - Oracle WebLogic Server independent of the version has 8 years of support of new patches and has lifetime release of existing patches beyond that. JBoss EAP 6 on the other hand provides patches for a specific application server version up to 5 years after the release date. JBoss EAP 4 and previous versions had only 4 years. A good question that Red Hat will argue to answer is: "what happens when you find issues after year 5"? 5) RAC ("Real Application Clusters") Support - WebLogic Server 12c ships with a specific JDBC driver to leverage Oracle RAC clustering capabilities (Fast-Application-Notification, Transaction Affinity, Fast-Connection-Failover, etc). Oracle JDBC thin driver are also available. JBoss EAP 6 on the other hand ships only the standard Oracle JDBC thin driver. Load balancing with Oracle RAC are not supported. Manual intervention in case of planned or unplanned RAC downtime are necessary. In JBoss EAP 6, situation does not reestablish automatically after downtime. - WebLogic Server 12c has a feature called Active GridLink for Oracle RAC which provides up to 3X performance on OLTP applications. This seamless integration between WebLogic and Oracle database enable more value added to critical business applications leveraging their investments in Oracle database technology and Oracle middleware. JBoss EAP 6 on the other hand has no performance gains at all, even when admin people implement some kind of connection-pooling tuning. - WebLogic Server 12c also supports transaction and web session affinity to the Oracle RAC, which provides aditional gains of performance. This is particularly interesting if you are creating a reliable solution that are distributed not only in an LAN cluster, but into a different data center. JBoss EAP 6 on the other hand has no such support. 6) Standards and Technology Support - WebLogic Server 12c is fully Java EE 6 compatible and production ready since december of 2011. JBoss EAP 6 on the other hand became fully compatible with Java EE 6 only in the community version after three months, and production ready only in a few days considering that this article was written in June of 2012. Red Hat says that they are the masters of innovation and technology proliferation, but compared with Oracle and even other proprietary vendors like IBM, they historically speaking are lazy to deliver the most newest technologies and standards adherence. - Oracle is the steward of Java, driving innovation into the platform from commercial and open-source vendors. Red Hat on the other hand does not have its own JVM and relies on third-part JVMs to complete their application server offer. 95% of Red Hat customers are using Oracle HotSpot as JVM, which means that without Oracle involvement, their support are limited exclusively to the application server layer and we all know that most problems are happens in the JVM layer. - WebLogic Server 12c supports natively JDK 7, which empower developers to explore the maximum of the Java platform productivity when writing code. This feature differentiate WebLogic from others application servers (except GlassFish that are also managed by Oracle) because the usage of JDK 7 introduce such remarkable productivity features like the "try-with-resources" enhancement, catching multiple exceptions with one try block, Strings in the switch statements, JVM improvements in terms of JDBC, I/O, networking, security, concurrency and of course, the most important feature of Java 7: native support for multiple non-Java languages. More features regarding JDK 7 can be found here. JBoss EAP 6 on the other hand does not support JDK 7 officially, they comment in their community version that "Java SE 7 can be used with JBoss 7" which does not gives you any guarantees of enterprise support for JDK 7. - Oracle WebLogic Server 12c supports integration with Spring framework allowing Spring applications to use WebLogic special transaction manager, exposing bean interfaces to WebLogic MBeans to take advantage of all WebLogic monitoring and administration advantages. JBoss EAP 6 on the other hand has no special integration with Spring. In fact, Red Hat offers a suspicious package called "JBoss Web Platform" that in theory supports Spring, but in practice this package does not offers any special integration. It is just a facility for Red Hat customers to have support from both JBoss and Spring technology using the same customer support. 7) Lightweight Development - Oracle WebLogic Server 12c and Oracle GlassFish are completely integrated and can share applications without any modifications. Starting with the 12c version, WebLogic now understands natively GlassFish deployment descriptors and specific configurations in order to offer you a truly and reliable migration path from a community Java EE application server to a enterprise middleware product like WebLogic. JBoss EAP 6 on the other hand has no support to natively reuse an existing (or still in development) application from JBoss AS community server. Users of JBoss suffer of critical issues during deployment time that includes: changing the libraries and dependencies of the application, patching the DTD or XSD deployment descriptors, refactoring of the application layers due classloading issues and anomalies, rebuilding of persistence, business and web layers due issues with "usage of the certified version of an certain dependency" or "frameworks that Red Hat potentially does not recommend" etc. If you have the culture or enterprise IT directive of developing Java EE applications using community middleware to in a certain future, transition to enterprise (supported by a vendor) middleware, Oracle WebLogic plus Oracle GlassFish offers you a more sustainable solution. - WebLogic Server 12c has a very light ZIP distribution (less than 165 MB). JBoss EAP 6 ZIP size is around 130 MB, together with JBoss ON you have more 100 MB resulting in a higher download footprint. This is particularly interesting if you plan to use automated setup of application server instances (for example, to rapidly setup a development or staging environment) using Maven or Hudson. - WebLogic Server 12c has a complete integration with Maven allowing developers to setup WebLogic domains with few commands. Tasks like downloading WebLogic, installation, domain creation, data sources deployment are completely integrated. JBoss EAP 6 on the other hand has a limited offer integration with those tools. - WebLogic Server 12c has a startup mode called WLX that turns-off EJB, JMS and JCA containers leaving enabled only the web container with Java EE 6 web profile. JBoss EAP 6 on the other hand has no such feature, you need to disable manually the containers that you do not want to use. - WebLogic Server 12c supports fastswap, which enables you to change classes without redeployment. This is particularly interesting if you are developing patches for the application that is already deployed and you do not want to redeploy the entire application. This is the same behavior that most application servers offers to JSP pages, but with WebLogic Server 12c, you have the same feature for Java classes in general. JBoss EAP 6 on the other hand has no such support. Even JBoss EAP 5 does not support this until now. 8) JMS and Messaging - WebLogic Server 12c has a proven and high scalable JMS implementation since its initial release in 1995. JBoss EAP 6 on the other hand has a still immature technology called HornetQ, which was introduced in JBoss EAP 5 replacing everything that was implemented in the previous versions. Red Hat loves to introduce new technologies across JBoss versions, playing around with customers and their investments. And when they are asked about why they have changed the implementation and caused such a mess, their answer is always: "the previous implementation was inadequate and not aligned with the community strategy so we are creating a new a improved one". This Red Hat practice leads to uncomfortable investments that in a near future (sometimes less than a year) will be affected in someway. - WebLogic Server 12c has troubleshooting and monitoring features included on the WebLogic console and WLDF. JBoss EAP 6 on the other hand has no direct monitoring on the console, activity is reflected only on the logs, no debug logs available in case of JMS issues. - WebLogic Server 12c has extremely good performance and scalability. JBoss EAP 6 on the other hand has a JMS storage mechanism relying on Oracle database or MySQL. This means that if an issue in production happens and Red Hat affirms that an performance issue is happening due to database problems, they will not support you on the performance issue. They will orient you to call Oracle instead. - WebLogic Server 12c supports messaging enterprise features like SAF ("Store and Forward"), Distributed Queues/Topics and Foreign JMS providers support that leverage JMS implementations without compromise developer code making things completely transparent. JBoss EAP 6 on the other hand do not even dream to support such features. 9) Caching and Grid - Coherence, which is the leading and most mature data grid technology from Oracle, is available since early 2000 and was integrated with WebLogic in 2009. Coherence and WebLogic clusters can be both managed from WebLogic administrative console. Even Node Manager supports Coherence. JBoss on the other hand discontinued JBoss Cache, which was their caching implementation just like they did with the messaging implementation (JBossMQ) which was a issue for long term customers. JBoss EAP 6 ships InfiniSpan version 1.0 which is immature and lack a proven record of successful cases and reliability. - WebLogic Server 12c has a feature called ActiveCache which uses Coherence to, without any code changes, replicate HTTP sessions from both WebLogic and other application servers like JBoss, Tomcat, Websphere, GlassFish and even Microsoft IIS. JBoss EAP 6 on the other hand does have such support and even when they do in the future, they probably will support only their own application server. - Coherence can be used to manage both L1 and L2 cache levels, providing support to Oracle TopLink and others JPA compliant implementations, even Hibernate. JBoss EAP 6 and Infinispan on the other hand supports only Hibernate. And most important of all: Infinispan does not have any successful case of L1 or L2 caching level support using Hibernate, which lead us to reflect about its viability. 10) Performance - WebLogic Server 12c is certified with Oracle Exalogic Elastic Cloud and can run unchanged applications at this engineered system. This approach can benefit customers from Exalogic optimization's of both kernel and JVM layers to boost performance in terms of 10X for web, OLTP, JMS and grid applications. JBoss EAP 6 on the other hand has no investment on engineered systems: customers do not have the choice to deploy on a Java ultra fast system if their project becomes relevant and performance issues are detected. - WebLogic Server 12c maintains a performance gain across each new release: starting on WebLogic 5.1, the overall performance gain has been close to 4X, which close to a 20% gain release by release. JBoss on the other hand does not provide SPECJAppServer or SPECJEnterprise performance benchmarks. Their so called "performance gains" remains hidden in their customer environments, which lead us to think if it is true or not since we will never get access to those environments. - WebLogic Server 12c has industry performance benchmarks with submissions across platforms and configurations leading SPECJ. Oracle WebLogic leads SPECJAppServer performance in multiple categories, fitting all customer topologies like: dual-node, single-node, multi-node and multi-node with RAC. JBoss... again, does not provide any SPECJAppServer performance benchmarks. - WebLogic Server 12c has a feature called work manager which allows your application to embrace new performance levels based on critical resource utilization of the CPUs usage. Work managers prioritizes work and allocates threads based on an execution model that takes into account administrator-defined parameters and actual run-time performance and throughput. JBoss EAP 6 on the other hand has no compared feature and probably they never will. Not supporting such feature like work managers, JBoss EAP 6 forces admin people and specially developers to uncover performance gains in a intrusive way, rewriting the code and doing performance refactorings. 11) Professional Services Support - WebLogic Server 12c and any other technology sold by Oracle give customers the possibility of hire OCS ("Oracle Consulting Services") to manage critical scenarios, deployment assistance of new applications, high skilled consultancy of architecture, best practices and people allocation together with customer teams. All OCS services are available without any restrictions, having the customer bought software from Oracle or just starting their implementation before any acquisition. JBoss EAP 6 or Red Hat to be more specifically, only offers professional services if you buy subscriptions from them. If you are developing a new critical application for your business and need the help of Red Hat for a serious issue or architecture decision, they will probably say: "OK... I can help you but after you buy subscriptions from me". Red Hat also does not allows their professional services consultants to manage environments that uses community based software. They will probably force you to first buy a subscription, download their "enterprise" version and them, optionally hire their consultants. - Oracle provides you our university to educate your team into our technologies, including of course specialized trainings of WebLogic application server. At any time and location, you can hire Oracle to train your team so you get trustful knowledge according to your specific needs. Certifications for the products are also available if your technical people desire to differentiate themselves as professionals. Red Hat on the other hand have a limited pool of resources to train your team in their technologies. Basically they are selling training and certification for RHEL ("Red Hat Enterprise Linux") but if you demand more specialized training in JBoss middleware, they will probably connect you to some "certified" partner localized training since they are apparently discontinuing their education center, at least here in Brazil. They were not able to reproduce their success with RHEL education to their middleware division since they need first sell the subscriptions to after gives you specialized training. And again, they only offer you specialized training based on their enterprise version (EAP in the case of JBoss) which means that the courses will be a quite outdated. There are reports of developers that took official training's from Red Hat at this year (2012) and in a certain JBoss advanced course, Red Hat supposedly covered JBossMQ as the messaging subsystem, and even the printed material provided was based on JBossMQ since the training was created for JBoss EAP 4.3. 12) Encouraging Transparency without Ulterior Motives - WebLogic Server 12c like any other software from Oracle can be downloaded any time from anywhere, you should only possess an OTN ("Oracle Technology Network") credential and you can download any enterprise software how many times you want. And is not some kind of "trial" version. It is the official binaries that will be running for ever in your data center. Oracle does not encourages the usage of "specific versions" of our software. The binaries you buy from Oracle are the same binaries anyone in the world could download and use for testing and personal education. JBoss EAP 6 on the other hand are not available for download unless you buy a subscription and get access to the Red Hat enterprise repositories. If you need to test, learn or just start creating your application using Red Hat's middleware software, you should download it from the community website. You are not allowed to download the enterprise version that, according to Red Hat are more secure, reliable and robust. But no one of us want to start the development of a software with an unsecured, unreliable and not scalable middleware right? So what you do? You are "invited" by Red Hat to buy subscriptions from them to get access to the "cool" version of the software. - WebLogic Server 12c prices are publicly available in the Oracle website. If you want to know right now how much WebLogic will cost to your organization, just click here and get access to our price list. In the case of WebLogic, check out the "US Oracle Technology Commercial Price List". Oracle also encourages you to get in touch with a sales representative to discuss discounts that would make possible the investment into our technology. But you are not required to do this, only if you are interested in buying our technology or maybe you want to discuss some discount scenarios. JBoss EAP 6 on the other hand does not have its cost publicly available in Red Hat's website or in any other media, at least is not so easy to get such information. The only link you will possibly find in their website is a "Contact a Sales Representative" link. This is not a very good relationship between an customer and an vendor. This is not an example of transparency, mainly when the software are sold as open. In this situations, customers expects to see the software prices publicly available, so they can have the chance to decide, based on the existing features of the software, if the cost is fair or not. Conclusion Oracle WebLogic is the most mature, secure, reliable and scalable Java EE application server of the market, and have a proven record of success around the globe to prove it's majority. Don't lose the chance to discover today how WebLogic could fit your needs and sustain your global IT middleware strategy, no matter if your strategy are completely based on the Cloud or not.

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Ruby on Rails: url_for :back leads to NoMethodError for back_url

- by Platinum Azure

Hi all, I'm trying to use url_for(:back) to create a redirect leading back to a previous page upon a user's logging in. I've had it working successfully for when the user just goes to the login page on his or her own. However, when the user is redirected to the login page due to accessing a page requiring that the user be authenticated, the redirect sends the user back to the page before the one s/he had tried to access with insufficient permissions. I'm trying to modify my login controller action to deal with the redirect properly. My plan is to have a query string parameter "redirect" that is used when a forced redirect occurs. In the controller, if that parameter exists that URL is used; otherwise, url_for(:back) is used, or if that doesn't work (due to lack of HTTP_REFERER), then the user is redirected to the site's home page. Here is the code snippet which is supposed to implement this logic: if params[:redirect] @url = params[:redirect] else @url = url_for :back @url ||= url_for :controller => "home", :action => "index" end The error I get is: NoMethodError in UsersController#login undefined method `back_url' for # RAILS_ROOT: [obscured] Application Trace | Framework Trace | Full Trace vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' app/controllers/users_controller.rb:16:in `login' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' vendor/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action' vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache' vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support' vendor/rails/actionpack/lib/action_controller/session_management.rb:134:in `process' vendor/rails/actionpack/lib/action_controller/base.rb:392:in `process' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `synchronize' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/railties/lib/commands/servers/mongrel.rb:64 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/railties/lib/commands/server.rb:49 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' app/controllers/users_controller.rb:16:in `login' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' vendor/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action' vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache' vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support' vendor/rails/actionpack/lib/action_controller/session_management.rb:134:in `process' vendor/rails/actionpack/lib/action_controller/base.rb:392:in `process' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `synchronize' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/railties/lib/commands/servers/mongrel.rb:64 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/railties/lib/commands/server.rb:49 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 Request Parameters: None Show session dump --- :user: :csrf_id: 2927cca61bbbe97218362b5bcdb74c0f flash: !map:ActionController::Flash::FlashHash {} Response Headers: {"Content-Type"="", "cookie"=[], "Cache-Control"="no-cache"} Bear in mind that I had it working earlier-- url_for(:back) knew how to operate properly before I added this logic. Thanks in advance for any ideas!

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Glassfish 3 Cant update JDK no way

- by Parhs

Hello.. I was using 1.6.0_19 jdk and installed 1.6.0_20 jdk.. Glassfish doesnt like that... Here are my windows environment variables.. ALLUSERSPROFILE=C:\ProgramData ANT_HOME=C:\apache-ant-1.8.1\ APPDATA=C:\Users\Parhs\AppData\Roaming CommonProgramFiles=C:\Program Files\Common Files COMPUTERNAME=PARHS-PC ComSpec=C:\Windows\system32\cmd.exe FP_NO_HOST_CHECK=NO HOMEDRIVE=C: HOMEPATH=\Users\Parhs JAVA_HOME=C:\Program Files\Java\jdk1.6.0_20\ LOCALAPPDATA=C:\Users\Parhs\AppData\Local LOGONSERVER=\\PARHS-PC NUMBER_OF_PROCESSORS=2 OS=Windows_NT Path=C:\Program Files\PHP\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wb em;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Toshiba\Bluetoot h Toshiba Stack\sys\;C:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\apa che-ant-1.8.1\bin PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC PHPRC=C:\Program Files\PHP\php.ini PROCESSOR_ARCHITECTURE=x86 PROCESSOR_IDENTIFIER=x86 Family 6 Model 14 Stepping 8, GenuineIntel PROCESSOR_LEVEL=6 PROCESSOR_REVISION=0e08 ProgramData=C:\ProgramData ProgramFiles=C:\Program Files PROMPT=$P$G PSModulePath=C:\Windows\system32\WindowsPowerShell\v1.0\Modules\ PUBLIC=C:\Users\Public SESSIONNAME=Console SystemDrive=C: SystemRoot=C:\Windows TEMP=C:\Users\Parhs\AppData\Local\Temp TMP=C:\Users\Parhs\AppData\Local\Temp USERDOMAIN=Parhs-PC USERNAME=Parhs USERPROFILE=C:\Users\Parhs VS90COMNTOOLS=C:\Program Files\Microsoft Visual Studio 9.0\Common7\Tools\ windir=C:\Windows Also here is my asenv.bat REM DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. REM REM Copyright 2004-2009 Sun Microsystems, Inc. All rights reserved. REM REM Use is subject to License Terms REM set AS_IMQ_LIB=....\mq\lib set AS_IMQ_BIN=....\mq\bin set AS_CONFIG=..\config set AS_INSTALL=.. set AS_DEF_DOMAINS_PATH=..\domains set AS_DERBY_INSTALL=....\javadb set AS_JAVA="C:\Program Files\Java\jdk1.6.0_20" And although restarting system and server i am getting this report Operating System Information: Name of the Operating System: Windows 7 Binary Architecture name of the Operating System: x86, Version: 6.1 Number of processors available on the Operating System: 2 System load on the available processors for the last minute: -1.0. (Sum of running and queued runnable entities per minute) General Java Runtime Environment Information for the VM: 6152@Parhs-PC JRE BootClassPath: C:\glassfishv3\glassfish/modules/endorsed\javax.annotation.jar;C:\glassfishv3\glassfish/modules/endorsed\jaxb-api-osgi.jar;C:\glassfishv3\glassfish/modules/endorsed\webservices-api-osgi.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\resources.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\rt.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\sunrsasign.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\jce.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.6.0_19\jre\classes;C:\glassfishv3\glassfish\lib\monitor\btrace-boot.jar JRE ClassPath: C:\glassfishv3\glassfish\modules\glassfish.jar;C:\glassfishv3\glassfish\lib\monitor\btrace-agent.jar JRE Native Library Path: C:\Program Files\Java\jdk1.6.0_19\bin;.;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files\PHP\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Toshiba\Bluetooth Toshiba Stack\sys\;C:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\apache-ant-1.8.1\bin JRE name: Java HotSpot(TM) Client VM Vendor: Sun Microsystems Inc. Version: 16.2-b04 List of System Properties for the Java Virtual Machine: ANTLR_USE_DIRECT_CLASS_LOADING = true AS_CONFIG = C:\glassfishv3\glassfish\config\..\config AS_DEF_DOMAINS_PATH = C:\glassfishv3\glassfish\config\..\domains AS_DERBY_INSTALL = C:\glassfishv3\glassfish\config\..\..\javadb AS_IMQ_BIN = C:\glassfishv3\glassfish\config\..\..\mq\bin AS_IMQ_LIB = C:\glassfishv3\glassfish\config\..\..\mq\lib AS_INSTALL = C:\glassfishv3\glassfish\config\.. AS_JAVA = C:\Program Files\Java\jdk1.6.0_20\jre GlassFish_Platform = Felix awt.toolkit = sun.awt.windows.WToolkit catalina.base = C:\glassfishv3\glassfish\domains\domain1 catalina.home = C:\glassfishv3\glassfish\domains\domain1 catalina.useNaming = false com.sun.aas.configRoot = C:\glassfishv3\glassfish\config com.sun.aas.derbyRoot = C:\glassfishv3\javadb com.sun.aas.domainsRoot = C:\glassfishv3\glassfish\domains com.sun.aas.hostName = Parhs-PC com.sun.aas.imqBin = C:\glassfishv3\mq\bin com.sun.aas.imqLib = C:\glassfishv3\mq\lib com.sun.aas.installRoot = C:\glassfishv3\glassfish com.sun.aas.installRootURI = file:/C:/glassfishv3/glassfish/ com.sun.aas.instanceName = server com.sun.aas.instanceRoot = C:\glassfishv3\glassfish\domains\domain1 com.sun.aas.instanceRootURI = file:/C:/glassfishv3/glassfish/domains/domain1/ com.sun.aas.javaRoot = C:\Program Files\Java\jdk1.6.0_19\jre com.sun.enterprise.config.config_environment_factory_class = com.sun.enterprise.config.serverbeans.AppserverConfigEnvironmentFactory com.sun.enterprise.hk2.cacheDir = C:\glassfishv3\glassfish\domains\domain1\osgi-cache\felix com.sun.enterprise.jaccprovider.property.repository = C:\glassfishv3\glassfish\domains\domain1/generated/policy com.sun.enterprise.security.httpsOutboundKeyAlias = s1as common.loader = ${catalina.home}/common/classes,${catalina.home}/common/endorsed/*.jar,${catalina.home}/common/lib/*.jar eclipselink.security.usedoprivileged = true ejb.home = C:\glassfishv3\glassfish\modules\ejb felix.config.properties = file:/C:/glassfishv3/glassfish/osgi/felix/conf/config.properties felix.fileinstall.bundles.new.start = true felix.fileinstall.debug = 1 felix.fileinstall.dir = C:\glassfishv3\glassfish/modules/autostart/ felix.fileinstall.poll = 5000 felix.system.properties = file:/C:/glassfishv3/glassfish/osgi/felix/conf/system.properties file.encoding = Cp1253 file.encoding.pkg = sun.io file.separator = \ glassfish.version = GlassFish v3 (build 74.2) hk2.startup.context.args = #Mon Jun 07 20:27:37 EEST 2010 -startup-classpath=C\:\\glassfishv3\\glassfish\\modules\\glassfish.jar;C\:\\glassfishv3\\glassfish\\lib\\monitor\\btrace-agent.jar __time_zero=1275931657334 hk2.startup.context.mainModule=org.glassfish.core.kernel -startup-args=--domain,,,domain1,,,--domaindir,,,C\:\\glassfishv3\\glassfish\\domains\\domain1 --domain=domain1 -startup-classname=com.sun.enterprise.glassfish.bootstrap.ASMain --domaindir=C\:\\glassfishv3\\glassfish\\domains\\domain1 hk2.startup.context.root = C:\glassfishv3\glassfish\modules http.nonProxyHosts = localhost|127.0.0.1|Parhs-PC java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironment java.awt.printerjob = sun.awt.windows.WPrinterJob java.class.path = C:\glassfishv3\glassfish\modules\glassfish.jar;C:\glassfishv3\glassfish\lib\monitor\btrace-agent.jar java.class.version = 50.0 java.endorsed.dirs = C:\glassfishv3\glassfish/modules/endorsed;C:\glassfishv3\glassfish/lib/endorsed java.ext.dirs = C:\Program Files\Java\jdk1.6.0_19\jre/lib/ext;C:\Program Files\Java\jdk1.6.0_19\jre/jre/lib/ext;C:\glassfishv3\glassfish\domains\domain1/lib/ext java.home = C:\Program Files\Java\jdk1.6.0_19\jre java.io.tmpdir = C:\Users\Parhs\AppData\Local\Temp\ java.library.path = C:\Program Files\Java\jdk1.6.0_19\bin;.;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files\PHP\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Toshiba\Bluetooth Toshiba Stack\sys\;C:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\apache-ant-1.8.1\bin java.net.useSystemProxies = true java.rmi.server.randomIDs = true java.runtime.name = Java(TM) SE Runtime Environment java.runtime.version = 1.6.0_19-b04 java.security.auth.login.config = C:\glassfishv3\glassfish\domains\domain1/config/login.conf java.security.policy = C:\glassfishv3\glassfish\domains\domain1/config/server.policy java.specification.name = Java Platform API Specification java.specification.vendor = Sun Microsystems Inc. java.specification.version = 1.6 java.util.logging.config.file = C:\glassfishv3\glassfish\domains\domain1\config\logging.properties java.vendor = Sun Microsystems Inc. java.vendor.url = http://java.sun.com/ java.vendor.url.bug = http://java.sun.com/cgi-bin/bugreport.cgi java.version = 1.6.0_19 java.vm.info = mixed mode java.vm.name = Java HotSpot(TM) Client VM java.vm.specification.name = Java Virtual Machine Specification java.vm.specification.vendor = Sun Microsystems Inc. java.vm.specification.version = 1.0 java.vm.vendor = Sun Microsystems Inc. java.vm.version = 16.2-b04 javax.net.ssl.keyStore = C:\glassfishv3\glassfish\domains\domain1/config/keystore.jks javax.net.ssl.keyStorePassword = changeit javax.net.ssl.trustStore = C:\glassfishv3\glassfish\domains\domain1/config/cacerts.jks javax.net.ssl.trustStorePassword = changeit javax.rmi.CORBA.PortableRemoteObjectClass = com.sun.corba.ee.impl.javax.rmi.PortableRemoteObject javax.rmi.CORBA.StubClass = com.sun.corba.ee.impl.javax.rmi.CORBA.StubDelegateImpl javax.rmi.CORBA.UtilClass = com.sun.corba.ee.impl.javax.rmi.CORBA.Util javax.security.jacc.PolicyConfigurationFactory.provider = com.sun.enterprise.security.provider.PolicyConfigurationFactoryImpl jdbc.drivers = org.apache.derby.jdbc.ClientDriver jpa.home = C:\glassfishv3\glassfish\modules\jpa line.separator = org.glassfish.web.rfc2109_cookie_names_enforced = false org.jvnet.hk2.osgimain.autostartBundles = osgi-adapter.jar, org.apache.felix.shell.jar, org.apache.felix.shell.remote.jar, org.apache.felix.configadmin.jar, org.apache.felix.fileinstall.jar org.jvnet.hk2.osgimain.bundlesDir = C:\glassfishv3\glassfish\modules org.jvnet.hk2.osgimain.excludedSubDirs = autostart/ org.omg.CORBA.ORBClass = com.sun.corba.ee.impl.orb.ORBImpl org.omg.CORBA.ORBSingletonClass = com.sun.corba.ee.impl.orb.ORBSingleton org.osgi.framework.storage = C:\glassfishv3\glassfish\domains\domain1\osgi-cache\felix os.arch = x86 os.name = Windows 7 os.version = 6.1 osgi.shell.telnet.ip = 127.0.0.1 osgi.shell.telnet.maxconn = 1 osgi.shell.telnet.port = 6666 package.access = package.definition = path.separator = ; security.home = C:\glassfishv3\glassfish\modules\security server.loader = ${catalina.home}/server/classes,${catalina.home}/server/lib/*.jar shared.loader = ${catalina.home}/shared/classes,${catalina.home}/shared/lib/*.jar sun.arch.data.model = 32 sun.boot.class.path = C:\glassfishv3\glassfish/modules/endorsed\javax.annotation.jar;C:\glassfishv3\glassfish/modules/endorsed\jaxb-api-osgi.jar;C:\glassfishv3\glassfish/modules/endorsed\webservices-api-osgi.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\resources.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\rt.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\sunrsasign.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\jce.jar;C:\Program Files\Java\jdk1.6.0_19\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.6.0_19\jre\classes;C:\glassfishv3\glassfish\lib\monitor\btrace-boot.jar sun.boot.library.path = C:\Program Files\Java\jdk1.6.0_19\jre\bin sun.cpu.endian = little sun.cpu.isalist = pentium_pro+mmx pentium_pro pentium+mmx pentium i486 i386 i86 sun.desktop = windows sun.io.unicode.encoding = UnicodeLittle sun.java.launcher = SUN_STANDARD sun.jnu.encoding = Cp1253 sun.management.compiler = HotSpot Client Compiler sun.os.patch.level = user.country = GR user.dir = C:\glassfishv3\glassfish\domains\domain1 user.home = C:\Users\Parhs user.language = el user.name = Parhs user.timezone = Europe/Athens user.variant = web.home = C:\glassfishv3\glassfish\modules\web weld.home = C:\glassfishv3\glassfish\modules\weld Why it is so damn hard??? What am i missing?

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Memory leak involving jQuery Ajax requests

- by Eli Courtwright

I have a webpage that's leaking memory in both IE8 and Firefox; the memory usage displayed in the Windows Process Explorer just keeps growing over time. The following page requests the "unplanned.json" url, which is a static file that never changes (though I do set my Cache-control HTTP header to no-cache to make sure that the Ajax request always goes through). When it gets the results, it clears out an HTML table, loops over the json array it got back from the server, and dynamically adds a row to an HTML table for each entry in the array. Then it waits 2 seconds and repeats this process. Here's the entire webpage: <html> <head> <title>Test Page</title> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script> </head> <body> <script type="text/javascript"> function kickoff() { $.getJSON("unplanned.json", resetTable); } function resetTable(rows) { $("#content tbody").empty(); for(var i=0; i<rows.length; i++) { $("<tr>" + "<td>" + rows[i].mpe_name + "</td>" + "<td>" + rows[i].bin + "</td>" + "<td>" + rows[i].request_time + "</td>" + "<td>" + rows[i].filtered_delta + "</td>" + "<td>" + rows[i].failed_delta + "</td>" + "</tr>").appendTo("#content tbody"); } setTimeout(kickoff, 2000); } $(kickoff); </script> <table id="content" border="1" style="width:100% ; text-align:center"> <thead><tr> <th>MPE</th> <th>Bin</th> <th>When</th> <th>Filtered</th> <th>Failed</th> </tr></thead> <tbody></tbody> </table> </body> </html> If it helps, here's an example of the json I'm sending back (it's this exact array wuith thousands of entries instead of just one): [ { mpe_name: "DBOSS-995", request_time: "09/18/2009 11:51:06", bin: 4, filtered_delta: 1, failed_delta: 1 } ] EDIT: I've accepted Toran's extremely helpful answer, but I feel I should post some additional code, since his removefromdom jQuery plugin has some limitations: It only removes individual elements. So you can't give it a query like `$("#content tbody tr")` and expect it to remove all of the elements you've specified. Any element that you remove with it must have an `id` attribute. So if I want to remove my `tbody`, then I must assign an `id` to my `tbody` tag or else it will give an error. It removes the element itself and all of its descendants, so if you simply want to empty that element then you'll have to re-create it afterwards (or modify the plugin to empty instead of remove). So here's my page above modified to use Toran's plugin. For the sake of simplicity I didn't apply any of the general performance advice offered by Peter. Here's the page which now no longer memory leaks: <html> <head> <title>Test Page</title> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script> </head> <body> <script type="text/javascript">  </script> <div id="message" style="color:red"></div> <table id="content" border="1" style="width:100% ; text-align:center"> <thead><tr> <th>MPE</th> <th>Bin</th> <th>When</th> <th>Filtered</th> <th>Failed</th> </tr></thead> <tbody id="id_field_required"></tbody> </table> </body> </html> FURTHER EDIT: I'll leave my question unchanged, though it's worth noting that this memory leak has nothing to do with Ajax. In fact, the following code would memory leak just the same and be just as easily solved with Toran's removefromdom jQuery plugin: function resetTable() { $("#content tbody").empty(); for(var i=0; i<1000; i++) { $("#content tbody").append("<tr><td>" + "DBOSS-095" + "</td>" + "<td>" + 4 + "</td>" + "<td>" + "09/18/2009 11:51:06" + "</td>" + "<td>" + 1 + "</td>" + "<td>" + 1 + "</td></tr>"); } setTimeout(resetTable, 2000); } $(resetTable);

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Bogus InvalidOperationException (in a DataServiceRequestException)

- by Andrei Rinea

I am having a hard time with ADO.NET Data Services (formerly code-named Astoria) as it gives me a bogus exception when I try to insert a new entity from the silverlight client and trying in a clean project (the same code) doesn't. In both cases, however, data is correctly inserted into the database. Using Fiddler (an HTTP debugger I could see that there is no problem in the HTTP communication as I will show later in this question. The code : var ctx = new MyProject123Entities(new Uri("http://andreiri/MyProject.Data/Data.svc")); var i = new Zone() { Data = DateTime.Now, IdElement = 1 }; ctx.AddToZone(i); i.StareZone = new StareZone() { IdStareZone = 1 }; ctx.AttachTo("StareZone", i.StareZone); ctx.SetLink(i, "StareZone", i.StareZone); i.TipZone = new TipZone() { IdTipZone = 1 }; ctx.AttachTo("TipZone", i.TipZone); ctx.SetLink(i, "TipZone", i.TipZone); i.User = new User() { IdUser = 2 }; ctx.AttachTo("User", i.User); ctx.SetLink(i, "User", i.User); ctx.BeginSaveChanges(r =] ctx.EndSaveChanges(r), null); when run the last line (ctx.EndSaveChanges(r)) will throw the following exception : System.Data.Services.Client.DataServiceRequestException was unhandled by user code Message="An error occurred while processing this request." StackTrace: at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.HandleBatchResponse() at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.EndRequest() at System.Data.Services.Client.DataServiceContext.EndSaveChanges(IAsyncResult asyncResult) at MyProject.MainPage.[]c__DisplayClassd6.[]c__DisplayClassd8.[dashboard_PostZoneCurent]b__d5(IAsyncResult r) at System.Data.Services.Client.BaseAsyncResult.HandleCompleted() at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.HandleCompleted(PerRequest pereq) at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.AsyncEndRead(IAsyncResult asyncResult) at System.IO.Stream.BeginRead(Byte[] buffer, Int32 offset, Int32 count, AsyncCallback callback, Object state) at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.AsyncEndGetResponse(IAsyncResult asyncResult) InnerException: System.InvalidOperationException Message="The context is already tracking a different entity with the same resource Uri." StackTrace: at System.Data.Services.Client.DataServiceContext.AttachTo(Uri identity, Uri editLink, String etag, Object entity, Boolean fail) at System.Data.Services.Client.MaterializeAtom.MoveNext() at System.Data.Services.Client.DataServiceContext.HandleResponsePost(ResourceBox entry, MaterializeAtom materializer, Uri editLink, String etag) at System.Data.Services.Client.DataServiceContext.SaveAsyncResult.[HandleBatchResponse]d__1d.MoveNext() InnerException: (there is no further information regarding the exception although the ADo.NET Data Service is configured to return detailed informations) However the row is inserted correctly and completely in the database. Using fiddler I can see that the request : <?xml version="1.0" encoding="utf-8" standalone="yes"?> <entry xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <category scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" term="MyProject123Model.Zone" /> <title /> <updated>2009-09-11T13:36:46.917157Z</updated> <author> <name /> </author> <id /> <link href="http://andreiri/MyProject.Data/Data.svc/StareZone(1)" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/StareZone" type="application/atom+xml;type=entry" /> <link href="http://andreiri/MyProject.Data/Data.svc/TipZone(4)" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/TipZone" type="application/atom+xml;type=entry" /> <link href="http://andreiri/MyProject.Data/Data.svc/User(4)" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/User" type="application/atom+xml;type=entry" /> <content type="application/xml"> <m:properties> <d:Data m:type="Edm.DateTime">2009-09-11T16:36:40.588951+03:00</d:Data> <d:Detalii>aslkdfjasldkfj</d:Detalii> <d:IdElement m:type="Edm.Int32">1</d:IdElement> <d:IdZone m:type="Edm.Int32">0</d:IdZone> <d:X_Post m:type="Edm.Decimal">587647.4705</d:X_Post> <d:X_Repost m:type="Edm.Decimal" m:null="true" /> <d:Y_Post m:type="Edm.Decimal">325783.077599999</d:Y_Post> <d:Y_Repost m:type="Edm.Decimal" m:null="true" /> </m:properties> </content> </entry> is well accepted and a successful response is returned : HTTP/1.1 201 Created Date: Fri, 11 Sep 2009 13:36:47 GMT Server: Microsoft-IIS/6.0 X-Powered-By: ASP.NET X-AspNet-Version: 2.0.50727 DataServiceVersion: 1.0; Location: http://andreiri/MyProject.Data/Data.svc/Zone(75) Cache-Control: no-cache Content-Type: application/atom+xml;charset=utf-8 Content-Length: 2213 <?xml version="1.0" encoding="utf-8" standalone="yes"?> <entry xml:base="http://andreiri/MyProject.Data/Data.svc/" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <id>http://andreiri/MyProject.Data/Data.svc/Zone(75)</id> <title type="text"></title> <updated>2009-09-11T13:36:47Z</updated> <author> <name /> </author> <link rel="edit" title="Zone" href="Zone(75)" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/CenterZone" type="application/atom+xml;type=feed" title="CenterZone" href="Zone(75)/CenterZone" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/ZoneMobil" type="application/atom+xml;type=feed" title="ZoneMobil" href="Zone(75)/ZoneMobil" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/StareZone" type="application/atom+xml;type=entry" title="StareZone" href="Zone(75)/StareZone" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/TipZone" type="application/atom+xml;type=entry" title="TipZone" href="Zone(75)/TipZone" /> <link rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/User" type="application/atom+xml;type=entry" title="User" href="Zone(75)/User" /> <category term="MyProject123Model.Zone" scheme="http://schemas.microsoft.com ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:IdZone m:type="Edm.Int32">75</d:IdZone> <d:X_Post m:type="Edm.Decimal">587647.4705</d:X_Post> <d:Y_Post m:type="Edm.Decimal">325783.077599999</d:Y_Post> <d:X_Repost m:type="Edm.Decimal" m:null="true" /> <d:Y_Repost m:type="Edm.Decimal" m:null="true" /> <d:Data m:type="Edm.DateTime">2009-09-11T16:36:40.588951+03:00</d:Data> <d:Detalii>aslkdfjasldkfj</d:Detalii> <d:IdElement m:type="Edm.Int32">1</d:IdElement> </m:properties> </content> </entry> Why do I get an exception? And, using this in a clean project does not throw the exception..

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Project Euler #15

- by Aistina

Hey everyone, Last night I was trying to solve challenge #15 from Project Euler: Starting in the top left corner of a 2×2 grid, there are 6 routes (without backtracking) to the bottom right corner. How many routes are there through a 20×20 grid? I figured this shouldn't be so hard, so I wrote a basic recursive function: const int gridSize = 20; // call with progress(0, 0) static int progress(int x, int y) { int i = 0; if (x < gridSize) i += progress(x + 1, y); if (y < gridSize) i += progress(x, y + 1); if (x == gridSize && y == gridSize) return 1; return i; } I verified that it worked for a smaller grids such as 2×2 or 3×3, and then set it to run for a 20×20 grid. Imagine my surprise when, 5 hours later, the program was still happily crunching the numbers, and only about 80% done (based on examining its current position/route in the grid). Clearly I'm going about this the wrong way. How would you solve this problem? I'm thinking it should be solved using an equation rather than a method like mine, but that's unfortunately not a strong side of mine. Update: I now have a working version. Basically it caches results obtained before when a n×m block still remains to be traversed. Here is the code along with some comments: // the size of our grid static int gridSize = 20; // the amount of paths available for a "NxM" block, e.g. "2x2" => 4 static Dictionary<string, long> pathsByBlock = new Dictionary<string, long>(); // calculate the surface of the block to the finish line static long calcsurface(long x, long y) { return (gridSize - x) * (gridSize - y); } // call using progress (0, 0) static long progress(long x, long y) { // first calculate the surface of the block remaining long surface = calcsurface(x, y); long i = 0; // zero surface means only 1 path remains // (we either go only right, or only down) if (surface == 0) return 1; // create a textual representation of the remaining // block, for use in the dictionary string block = (gridSize - x) + "x" + (gridSize - y); // if a same block has not been processed before if (!pathsByBlock.ContainsKey(block)) { // calculate it in the right direction if (x < gridSize) i += progress(x + 1, y); // and in the down direction if (y < gridSize) i += progress(x, y + 1); // and cache the result! pathsByBlock[block] = i; } // self-explanatory :) return pathsByBlock[block]; } Calling it 20 times, for grids with size 1×1 through 20×20 produces the following output: There are 2 paths in a 1 sized grid 0,0110006 seconds There are 6 paths in a 2 sized grid 0,0030002 seconds There are 20 paths in a 3 sized grid 0 seconds There are 70 paths in a 4 sized grid 0 seconds There are 252 paths in a 5 sized grid 0 seconds There are 924 paths in a 6 sized grid 0 seconds There are 3432 paths in a 7 sized grid 0 seconds There are 12870 paths in a 8 sized grid 0,001 seconds There are 48620 paths in a 9 sized grid 0,0010001 seconds There are 184756 paths in a 10 sized grid 0,001 seconds There are 705432 paths in a 11 sized grid 0 seconds There are 2704156 paths in a 12 sized grid 0 seconds There are 10400600 paths in a 13 sized grid 0,001 seconds There are 40116600 paths in a 14 sized grid 0 seconds There are 155117520 paths in a 15 sized grid 0 seconds There are 601080390 paths in a 16 sized grid 0,0010001 seconds There are 2333606220 paths in a 17 sized grid 0,001 seconds There are 9075135300 paths in a 18 sized grid 0,001 seconds There are 35345263800 paths in a 19 sized grid 0,001 seconds There are 137846528820 paths in a 20 sized grid 0,0010001 seconds 0,0390022 seconds in total I'm accepting danben's answer, because his helped me find this solution the most. But upvotes also to Tim Goodman and Agos :) Bonus update: After reading Eric Lippert's answer, I took another look and rewrote it somewhat. The basic idea is still the same but the caching part has been taken out and put in a separate function, like in Eric's example. The result is some much more elegant looking code. // the size of our grid const int gridSize = 20; // magic. static Func<A1, A2, R> Memoize<A1, A2, R>(this Func<A1, A2, R> f) { // Return a function which is f with caching. var dictionary = new Dictionary<string, R>(); return (A1 a1, A2 a2) => { R r; string key = a1 + "x" + a2; if (!dictionary.TryGetValue(key, out r)) { // not in cache yet r = f(a1, a2); dictionary.Add(key, r); } return r; }; } // calculate the surface of the block to the finish line static long calcsurface(long x, long y) { return (gridSize - x) * (gridSize - y); } // call using progress (0, 0) static Func<long, long, long> progress = ((Func<long, long, long>)((long x, long y) => { // first calculate the surface of the block remaining long surface = calcsurface(x, y); long i = 0; // zero surface means only 1 path remains // (we either go only right, or only down) if (surface == 0) return 1; // calculate it in the right direction if (x < gridSize) i += progress(x + 1, y); // and in the down direction if (y < gridSize) i += progress(x, y + 1); // self-explanatory :) return i; })).Memoize(); By the way, I couldn't think of a better way to use the two arguments as a key for the dictionary. I googled around a bit, and it seems this is a common solution. Oh well.

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Spring @Transactional not creating required transaction

- by Steve

Ok, so I've finally bowed to peer pressure and started using Spring in my web app :-)... So I'm trying to get the transaction handling stuff to work, and I just can't seem to get it. My Spring configuration looks like this: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <bean id="groupDao" class="mil.navy.ndms.conops.common.dao.impl.jpa.GroupDao" lazy-init="true"> <property name="entityManagerFactory" ><ref bean="entityManagerFactory"/></property> </bean>  <bean class="org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor"/>  <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>  <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean"> <property name="persistenceUnitName" value="CONOPS_PU" /> </bean>  <bean id="jpaTransactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory"/> </bean>  <tx:annotation-driven transaction-manager="jpaTransactionManager" proxy-target-class="true"/> </beans> persistence.xml: <?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"> <persistence-unit name="CONOPS_PU" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> ... Class mappings removed for brevity... <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/> <property name="hibernate.connection.autocommit" value="false"/> <property name="hibernate.connection.username" value="****"/> <property name="hibernate.connection.password" value="*****"/> <property name="hibernate.connection.driver_class" value="oracle.jdbc.OracleDriver"/> <property name="hibernate.connection.url" value="jdbc:oracle:thin:@*****:1521:*****"/> <property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider"/> <property name="hibernate.hbm2ddl.auto" value="create"/> <property name="hibernate.show_sql" value="true"/> <property name="hibernate.format_sql" value="true"/> </properties> </persistence-unit> </persistence> The DAO method to save my domain object looks like this: @Transactional(propagation=Propagation.REQUIRES_NEW) protected final T saveOrUpdate (T model) { EntityManager em = emf.createEntityManager ( ); EntityTransaction trans = em.getTransaction ( ); System.err.println ("Transaction isActive () == " + trans.isActive ( )); if (em != null) { try { if (model.getId ( ) != null) { em.persist (model); em.flush (); } else { em.merge (model); em.flush (); } } finally { em.close (); } } return (model); } So I try to save a copy of my Group object using the following code in my test case: context = new ClassPathXmlApplicationContext(configs); dao = (GroupDao)context.getBean("groupDao"); dao.saveOrUpdate (new Group ()); This bombs with the following exception: javax.persistence.TransactionRequiredException: no transaction is in progress at org.hibernate.ejb.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:301) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:600) at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:341) at $Proxy26.flush(Unknown Source) at mil.navy.ndms.conops.common.dao.impl.jpa.GenericJPADao.saveOrUpdate(GenericJPADao.java:646) at mil.navy.ndms.conops.common.dao.impl.jpa.GroupDao.save(GroupDao.java:641) at mil.navy.ndms.conops.common.dao.impl.jpa.GroupDao$$FastClassByCGLIB$$50343b9b.invoke() at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622) at mil.navy.ndms.conops.common.dao.impl.jpa.GroupDao$$EnhancerByCGLIB$$7359ba58.save() at mil.navy.ndms.conops.common.dao.impl.jpa.GroupDaoTest.testGroupDaoSave(GroupDaoTest.java:91) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:600) at junit.framework.TestCase.runTest(TestCase.java:164) at junit.framework.TestCase.runBare(TestCase.java:130) at junit.framework.TestResult$1.protect(TestResult.java:106) at junit.framework.TestResult.runProtected(TestResult.java:124) at junit.framework.TestResult.run(TestResult.java:109) at junit.framework.TestCase.run(TestCase.java:120) at junit.framework.TestSuite.runTest(TestSuite.java:230) at junit.framework.TestSuite.run(TestSuite.java:225) at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:130) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196) In addition, I get the following warnings when Spring first starts. Since these reference the entityManagerFactory and the transactionManager, they probably have some bearing on the problem, but I've no been able to decipher them enough to know what: Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean 'entityManagerFactory' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean 'entityManagerFactory' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean 'jpaTransactionManager' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean '(inner bean)' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean '(inner bean)' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean 'org.springframework.transaction.interceptor.TransactionAttributeSourceAdvisor' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.context.support.AbstractApplicationContext$BeanPostProcessorChecker postProcessAfterInitialization INFO: Bean 'org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor' is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) Mar 11, 2010 12:19:27 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@37003700: defining beans [groupDao,org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor,org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor,entityManagerFactory,jpaTransactionManager,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.interceptor.TransactionAttributeSourceAdvisor]; root of factory hierarchy Does anyone have any idea what I'm missing? I'm totally stumped... Thanks

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Please help to clean up my RoR development environment

- by PeterWong

I started RoR development a few months ago, and being new to Mac... Time flies and now I have a lot different ruby versions, rails versions and gems versions located everywhere......And currently I installed rvm and things got even worst, all things messed! And so I started want to clean all things and use rvm again! I want to uninstall all gems, all rails, and all ruby versions, except the system's default one (the very old one born with the mac). Or any other better solutions or suggestions!? Please help! there is some info that I think will be useful: which -a ruby /opt/local/bin/ruby /opt/local/bin/ruby /usr/local/bin/ruby /usr/bin/ruby /usr/local/bin/ruby which -a rails /usr/local/bin/rails /usr/bin/rails /usr/local/bin/rails which -a compass # simliar for rspec and many other gems /usr/local/bin/compass /usr/local/bin/compass gem list *** LOCAL GEMS *** abstract (1.0.0) actionmailer (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2, 2.3.9, 2.3.5, 2.3.4) actionpack (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2, 2.3.9, 2.3.5, 2.3.4) activemodel (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2) activerecord (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2, 2.3.9, 2.3.5, 2.3.4) activeresource (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2, 2.3.9, 2.3.5, 2.3.4) activesupport (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2, 2.3.9, 2.3.5, 2.3.4) addressable (2.2.2) arel (2.0.6, 1.0.1, 1.0.0.rc1) authlogic (2.1.6, 2.1.3) aws-s3 (0.6.2) base32 (0.1.2) block_helpers (0.3.3) bluecloth (2.0.9) bowline (0.9.4) bowline-bundler (0.0.4) bson (1.1.2) builder (2.1.2) bundler (1.0.2, 1.0.0) compass (0.10.6) crack (0.1.7) devise (1.1.3) diff-lcs (1.1.2) differ (0.1.1) dynamic_form (1.1.3) engineyard (1.3.1) engineyard-serverside-adapter (1.3.3) erubis (2.6.6) escape (0.0.4) extlib (0.9.15) facebooker (1.0.75) faker (0.3.1) faraday (0.5.3, 0.5.2) fast_gettext (0.5.10, 0.4.17) fastercsv (1.5.3) fastthread (1.0.7) ffi (0.6.3) formatize (1.0.1) formtastic (1.1.0, 1.0.1) gemcutter (0.5.0) gettext (2.1.0) git (1.2.5) gosu (0.7.25 universal-darwin) haml (3.0.24, 3.0.23, 3.0.22, 3.0.21, 3.0.18) haml-rails (0.3.4) heroku (1.10.13, 1.9.13) highline (1.5.2) hirb (0.3.4, 0.3.3) hpricot (0.8.2) i18n (0.5.0, 0.4.2, 0.4.1, 0.3.7) jeweler (1.4.0) json (1.4.6) json_pure (1.4.3) linkedin (0.1.8) locale (2.0.5) mail (2.2.12, 2.2.11, 2.2.10, 2.2.9, 2.2.7, 2.2.6.1) memcache-client (1.8.5) meta_search (0.9.8, 0.9.7.2, 0.9.7.1, 0.9.6, 0.9.4) mime-types (1.16) mongo (1.1.2) mongoid (2.0.0.beta.20) multi_json (0.0.5) multipart-post (1.0.1) mysql (2.8.1) mysql2 (0.2.6, 0.2.4, 0.2.3) net-ldap (0.1.1) nice-ffi (0.4) nokogiri (1.4.4, 1.4.2) oa-basic (0.1.6) oa-core (0.1.6) oa-enterprise (0.1.6) oa-oauth (0.1.6) oa-openid (0.1.6) oauth (0.4.4, 0.4.3, 0.4.1) oauth-plugin (0.4.0.pre1) oauth2 (0.1.0) omniauth (0.1.6) paperclip (2.3.6, 2.3.4, 2.3.1.1) passenger (2.2.12) polyglot (0.3.1) pyu-ruby-sasl (0.0.3.2) querybuilder (0.9.2, 0.5.9) rack (1.2.1, 1.1.0, 1.0.1) rack-cache (0.5.3) rack-cache-purge (0.0.2, 0.0.1) rack-mount (0.6.13) rack-openid (1.2.0) rack-test (0.5.6, 0.5.4) railroady (0.11.2) rails (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2, 2.3.9, 2.3.5, 2.3.4) railties (3.0.3, 3.0.1, 3.0.0, 3.0.0.rc2) rake (0.8.7) RedCloth (3.0.4) rest-client (1.6.1) roxml (3.1.5) rscribd (1.2.0) rspec (2.3.0, 2.2.0, 2.1.0, 2.0.1) rspec-core (2.3.0, 2.2.1, 2.1.0, 2.0.1) rspec-expectations (2.3.0, 2.2.0, 2.1.0, 2.0.1) rspec-mocks (2.3.0, 2.2.0, 2.1.0, 2.0.1) rspec-rails (2.3.0, 2.2.0, 2.1.0, 2.0.1) ruby-hmac (0.4.0) ruby-mysql (2.9.3) ruby-ole (1.2.10.1) ruby-openid (2.1.8) ruby-openid-apps-discovery (1.2.0) ruby-recaptcha (1.0.2, 1.0.0) ruby-sdl-ffi (0.3) ruby-termios (0.9.6) ruby_parser (2.0.5) rubyforge (2.0.4) rubygame (2.6.4) rubygems-update (1.3.7) rubyless (0.7.0, 0.6.0, 0.3.5) rubyntlm (0.1.1) rubyzip2 (2.0.1) scribd_fu (2.0.6) searchlogic (2.4.27, 2.4.23) sequel (3.16.0, 3.15.0, 3.13.0) sexp_processor (3.0.5) shoulda (2.11.3) sinatra (1.0) slim (0.8.0) slim-rails (0.1.2) spreadsheet (0.6.4.1) sqlite3-ruby (1.3.2, 1.3.1) ssl_requirement (0.1.0) subdomain-fu (1.0.0.beta2, 0.5.4) supermodel (0.1.4) syntax (1.0.0) taps (0.3.13, 0.3.11) templater (1.0.0) temple (0.1.6) text-format (1.0.0) text-hyphen (1.0.0) thor (0.14.6, 0.14.4, 0.14.3, 0.14.1, 0.14.0) tilt (1.1) treetop (1.4.9, 1.4.8) tzinfo (0.3.23) uuidtools (2.1.1, 2.0.0) validates_timeliness (3.0.0.beta.4, 2.3.1) warden (0.10.7) will_paginate (3.0.pre2, 2.3.15, 2.3.14) xml-simple (1.0.12) ya2yaml (0.30) yajl-ruby (0.7.8, 0.7.7) yamltest (0.7.0) zena (0.16.9, 0.16.8) ====== I have ran sudo rvm implode and sudo rm -rf ~/.rvm, so no rvm now. gem env RubyGems Environment: - RUBYGEMS VERSION: 1.3.7 - RUBY VERSION: 1.8.7 (2009-06-12 patchlevel 174) [i686-darwin10.2.0] - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.8 - RUBY EXECUTABLE: /usr/local/bin/ruby - EXECUTABLE DIRECTORY: /usr/local/bin - RUBYGEMS PLATFORMS: - ruby - x86-darwin-10 - GEM PATHS: - /usr/local/lib/ruby/gems/1.8 - /Users/peter/.gem/ruby/1.8 - GEM CONFIGURATION: - :update_sources => true - :verbose => true - :benchmark => false - :backtrace => false - :bulk_threshold => 1000 - :sources => ["http://rubygems.org/", "http://gems.github.com"] - REMOTE SOURCES: - http://rubygems.org/ - http://gems.github.com === ls -al /usr/local/lib/ total 5704 drwxr-xr-x 7 root wheel 238 Jun 1 2010 . drwxr-xr-x 9 root wheel 306 Dec 15 16:20 .. -rw-r--r-- 1 root wheel 1717208 Jun 1 2010 libruby-static.a -rwxr-xr-x 1 root wheel 1191880 Jun 1 2010 libruby.1.8.7.dylib lrwxrwxrwx 1 root wheel 19 Jun 1 2010 libruby.1.8.dylib -> libruby.1.8.7.dylib lrwxrwxrwx 1 root wheel 19 Jun 1 2010 libruby.dylib -> libruby.1.8.7.dylib drwxr-xr-x 6 root wheel 204 Jun 1 2010 ruby

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JSF 2.0 Problem

- by Sarang

I am doing a project where I am using JSF 2.0 & Primefaces UI Components. There is a tab view component with tabs, "Day","Week" & "Month". In all tab, I have to display Bar Charts in each. For the same, I am fetching three list using the following three method. In the following code, UpdateCountHelper is fetching the data from database. So, UpdateCountHelper is taking some time for fetching data. This is code for fetching lists : public List<UpdateCount> getDayUpdateCounts() { if (projectFlag == true) { if (displayFlag == 1) { dayUpdateCounts = UpdateCountHelper.getProjectUpdates(1); } else { dayUpdateCounts = UpdateCountHelper.getProjectUpdates(name, 1); } } else { dayUpdateCounts = UpdateCountHelper.getResourceUpdates(userName, 1); } return dayUpdateCounts; } public List<UpdateCount> getMonthUpdateCounts() { if (projectFlag == true) { if (displayFlag == 1) { monthUpdateCounts = UpdateCountHelper.getProjectUpdates(30); } else { monthUpdateCounts = UpdateCountHelper.getProjectUpdates(name, 30); } } else { monthUpdateCounts = UpdateCountHelper.getResourceUpdates(userName, 30); } return monthUpdateCounts; } public List<UpdateCount> getWeekUpdateCounts() { if (projectFlag == true) { if (displayFlag == 1) { weekUpdateCounts = UpdateCountHelper.getProjectUpdates(7); } else { weekUpdateCounts = UpdateCountHelper.getProjectUpdates(name, 7); } } else { weekUpdateCounts = UpdateCountHelper.getResourceUpdates(userName, 7); } return weekUpdateCounts; } This is code for UI of Bar Chart : <p:panel id="Chart"> <p:tabView dynamic="false" cache="false"> <p:tab title="Day"> <p:panel id="chartDayPanel"> <center> <h:outputText id="projectWiseDayText" rendered="#{systemUtilizationServiceBean.projectFlag}" value="Project Wise Day Update"/> <p:columnChart id="projectWiseDayUpdateChart" rendered="#{systemUtilizationServiceBean.projectFlag}" value="#{systemUtilizationServiceBean.dayUpdateCounts}" var="dayWiseUpdate" xfield="#{dayWiseUpdate.name}" height="200px" width="640px"> <p:chartSeries label="Project Wise Current Day Update" value="#{dayWiseUpdate.noUpdates}"/> </p:columnChart> <h:outputText id="resourceWiseDayText" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="Resource Wise Day Update"/> <p:columnChart id="resourceWiseDayUpdateChart" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="#{systemUtilizationServiceBean.dayUpdateCounts}" var="dayWiseResourceUpdate" xfield="#{dayWiseResourceUpdate.name}" height="200px" width="640px"> <p:chartSeries label="Resource Wise Current Day Update" value="#{dayWiseResourceUpdate.noUpdates}"/> </p:columnChart> </center> </p:panel> </p:tab> <p:tab title="Week"> <p:panel id="chartWeekPanel"> <center> <h:outputText id="projectWiseWeekText" rendered="#{systemUtilizationServiceBean.projectFlag}" value="Project Wise Week Update"/> <p:columnChart id="projectWiseWeekUpdateChart" rendered="#{systemUtilizationServiceBean.projectFlag}" value="#{systemUtilizationServiceBean.weekUpdateCounts}" var="weekWiseUpdate" xfield="#{weekWiseUpdate.name}" height="200px" width="640px"> <p:chartSeries label="Project Wise Current Week Update" value="#{weekWiseUpdate.noUpdates}"/> </p:columnChart> <h:outputText id="resourceWiseWeekText" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="Resource Wise Week Update"/> <p:columnChart id="resourceWiseWeekUpdateChart" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="#{systemUtilizationServiceBean.weekUpdateCounts}" var="weekWiseResourceUpdate" xfield="#{weekWiseResourceUpdate.name}" height="200px" width="640px"> <p:chartSeries label="Resource Wise Current Week Update" value="#{weekWiseResourceUpdate.noUpdates}"/> </p:columnChart> </center> </p:panel> </p:tab> <p:tab title="Month"> <p:panel id="chartMonthPanel"> <center> <h:outputText id="projectWiseMonthText" rendered="#{systemUtilizationServiceBean.projectFlag}" value="Project Wise Month Update"/> <p:columnChart id="projectWiseMonthUpdateChart" rendered="#{systemUtilizationServiceBean.projectFlag}" value="#{systemUtilizationServiceBean.monthUpdateCounts}" var="monthWiseUpdate" xfield="#{monthWiseUpdate.name}" height="200px" width="640px"> <p:chartSeries label="Project Wise Current Month Update" value="#{monthWiseUpdate.noUpdates}"/> </p:columnChart> <h:outputText id="resourceWiseMonthText" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="Resource Wise Month Update"/> <p:columnChart id="resourceWiseMonthUpdateChart" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="#{systemUtilizationServiceBean.monthUpdateCounts}" var="monthWiseResourceUpdate" xfield="#{monthWiseResourceUpdate.name}" height="200px" width="640px"> <p:chartSeries label="Resource Wise Current Month Update" value="#{monthWiseResourceUpdate.noUpdates}"/> </p:columnChart> </center> </p:panel> </p:tab> </p:tabView> </p:panel> Now, I have to display same data in other tabview with same tabs as mentioned above & only thing is now I have to display in Pie Chart. Now in pie chart, I am using the same lists. So, it will again fetch the data from database & waste time. To solve that problem I have created other three lists & have given only reference of those previous lists. So, now no database fetching occur. The Code for applying the reference is : public List<UpdateCount> getPieDayUpdateCounts() { pieDayUpdateCounts = dayUpdateCounts; return pieDayUpdateCounts; } public List<UpdateCount> getPieMonthUpdateCounts() { pieMonthUpdateCounts = monthUpdateCounts; return pieMonthUpdateCounts; } public List<UpdateCount> getPieWeekUpdateCounts() { pieWeekUpdateCounts = weekUpdateCounts; return pieWeekUpdateCounts; } But, over here the problem occurring is that only chart of which the tab is enable is displayed but the other remaining 2 tabs are not showing any chart. The code for UI is : <p:tabView dynamic="false" cache="false"> <p:tab title="Day"> <center> <p:panel id="pieChartDayPanel"> <h:outputText id="projectWiseDayPieChartText" rendered="#{systemUtilizationServiceBean.projectFlag}" value="Project Wise Day Update"/> <p:pieChart id="projectWiseDayUpdatePieChart" rendered="#{systemUtilizationServiceBean.projectFlag}" value="#{systemUtilizationServiceBean.dayUpdateCounts}" var="dayWisePieUpdate" categoryField="#{dayWisePieUpdate.name}" dataField="#{dayWisePieUpdate.noUpdates}" height="200" width="200"/> <h:outputText id="resourceWiseDayPieChartText" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="Resource Wise Day Update"/> <p:pieChart id="resourceWiseDayUpdatePieChart" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="#{systemUtilizationServiceBean.dayUpdateCounts}" var="dayWiseResourcePieUpdate" categoryField="#{dayWiseResourcePieUpdate.name}" dataField="#{dayWiseResourcePieUpdate.noUpdates}" height="200" width="200"/> </p:panel> </center> </p:tab> <p:tab title="Week"> <center> <p:panel id="pieChartWeekPanel"> <h:outputText id="projectWiseWeekPieChartText" rendered="#{systemUtilizationServiceBean.projectFlag}" value="Project Wise Week Update"/> <p:pieChart id="projectWiseWeekUpdatePieChart" rendered="#{systemUtilizationServiceBean.projectFlag}" value="#{systemUtilizationServiceBean.weekUpdateCounts}" var="weekWisePieUpdate" categoryField="#{weekWisePieUpdate.name}" dataField="#{weekWisePieUpdate.noUpdates}" height="200" width="200"/> <h:outputText id="resourceWiseWeekPieChartText" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="Resource Wise Week Update"/> <p:pieChart id="resourceWiseWeekUpdatePieChart" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="#{systemUtilizationServiceBean.weekUpdateCounts}" var="weekWiseResourcePieUpdate" categoryField="#{weekWiseResourcePieUpdate.name}" dataField="#{weekWiseResourcePieUpdate.noUpdates}" height="200" width="200"/> </p:panel> </center> </p:tab> <p:tab title="Month"> <center> <p:panel id="pieChartMonthPanel"> <h:outputText id="projectWiseMonthPieChartText" rendered="#{systemUtilizationServiceBean.projectFlag}" value="Project Wise Month Update"/> <p:pieChart id="projectWiseMonthUpdatePieChart" rendered="#{systemUtilizationServiceBean.projectFlag}" value="#{systemUtilizationServiceBean.monthUpdateCounts}" var="monthWisePieUpdate" categoryField="#{monthWisePieUpdate.name}" dataField="#{monthWisePieUpdate.noUpdates}" height="200" width="200"/> <h:outputText id="resourceWiseMonthPieChartText" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="Resource Wise Month Update"/> <p:pieChart id="resourceWiseMonthUpdatePieChart" rendered="#{systemUtilizationServiceBean.resourceFlag}" value="#{systemUtilizationServiceBean.monthUpdateCounts}" var="monthWiseResourcePieUpdate" categoryField="#{monthWiseResourcePieUpdate.name}" dataField="#{monthWiseResourcePieUpdate.noUpdates}" height="200" width="200"/> </p:panel> </center> </p:tab> </p:tabView> What should be the reason behind this ?

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My App crashes when launched on my Iphone

- by Miky Mike

hi guys, I have a problem here : my app crashed on my Iphone (JB) though Xcode doesn't complain about anything. The app works fine on the simulator though. However, there is this in the device logs : Thread 0 Crashed: 0 libSystem.B.dylib 0x00078ac8 kill + 8 1 libSystem.B.dylib 0x00078ab8 kill + 4 2 libSystem.B.dylib 0x00078aaa raise + 10 3 libSystem.B.dylib 0x0008d03a abort + 50 4 libstdc++.6.dylib 0x00044a20 __gnu_cxx::__verbose_terminate_handler() + 376 5 libobjc.A.dylib 0x00005958 _objc_terminate + 104 6 libstdc++.6.dylib 0x00042df2 _cxxabiv1::_terminate(void (*)()) + 46 7 libstdc++.6.dylib 0x00042e46 std::terminate() + 10 8 libstdc++.6.dylib 0x00042f16 __cxa_throw + 78 9 libobjc.A.dylib 0x00004838 objc_exception_throw + 64 10 CoreFoundation 0x0009fd0e +[NSException raise:format:arguments:] + 62 11 CoreFoundation 0x0009fd48 +[NSException raise:format:] + 28 12 Foundation 0x000125d8 -[NSURL(NSURL) initFileURLWithPath:] + 64 13 Foundation 0x000371e0 +[NSURL(NSURL) fileURLWithPath:] + 24 14 TheLearningMachine 0x00002d08 0x1000 + 7432 15 TheLearningMachine 0x00002e8c 0x1000 + 7820 16 TheLearningMachine 0x00002be4 0x1000 + 7140 17 TheLearningMachine 0x000029b6 0x1000 + 6582 18 UIKit 0x0000e47a -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 766 19 UIKit 0x000049e0 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 200 20 UIKit 0x0005dfd6 -[UIApplication handleEvent:withNewEvent:] + 1390 21 UIKit 0x0005d8fa -[UIApplication sendEvent:] + 38 22 UIKit 0x0005d330 _UIApplicationHandleEvent + 5104 23 GraphicsServices 0x00005044 PurpleEventCallback + 660 24 CoreFoundation 0x00034cdc __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION + 20 25 CoreFoundation 0x00034ca0 __CFRunLoopDoSource1 + 160 26 CoreFoundation 0x00027566 __CFRunLoopRun + 514 27 CoreFoundation 0x00027270 CFRunLoopRunSpecific + 224 28 CoreFoundation 0x00027178 CFRunLoopRunInMode + 52 29 UIKit 0x000040fc -[UIApplication _run] + 364 30 UIKit 0x00002128 UIApplicationMain + 664 31 TheLearningMachine 0x00002948 0x1000 + 6472 32 TheLearningMachine 0x000028fc 0x1000 + 6396 Thread 1: 0 libSystem.B.dylib 0x0002d330 kevent + 24 1 libSystem.B.dylib 0x000d6b6c _dispatch_mgr_invoke + 88 2 libSystem.B.dylib 0x000d65bc _dispatch_queue_invoke + 96 3 libSystem.B.dylib 0x000d675c _dispatch_worker_thread2 + 120 4 libSystem.B.dylib 0x0007a67a _pthread_wqthread + 258 5 libSystem.B.dylib 0x00073190 start_wqthread + 0 Thread 2: 0 libSystem.B.dylib 0x0007b19c __workq_kernreturn + 8 1 libSystem.B.dylib 0x0007a790 _pthread_wqthread + 536 2 libSystem.B.dylib 0x00073190 start_wqthread + 0 Thread 3: 0 libSystem.B.dylib 0x00000c98 mach_msg_trap + 20 1 libSystem.B.dylib 0x00002d64 mach_msg + 44 2 CoreFoundation 0x00027c38 __CFRunLoopServiceMachPort + 88 3 CoreFoundation 0x000274c2 __CFRunLoopRun + 350 4 CoreFoundation 0x00027270 CFRunLoopRunSpecific + 224 5 CoreFoundation 0x00027178 CFRunLoopRunInMode + 52 6 WebCore 0x000024e2 RunWebThread(void*) + 362 7 libSystem.B.dylib 0x0007a27e _pthread_start + 242 8 libSystem.B.dylib 0x0006f2a8 thread_start + 0 Thread 0 crashed with ARM Thread State: r0: 0x00000000 r1: 0x00000000 r2: 0x00000001 r3: 0x3e0862b4 r4: 0x00000006 r5: 0x0015a2ec r6: 0x2fffe090 r7: 0x2fffe0a0 r8: 0x3e1a378c r9: 0x00000065 r10: 0x33028e5a r11: 0x3e1ab89c ip: 0x00000025 sp: 0x2fffe0a0 lr: 0x30277abf pc: 0x30277ac8 cpsr: 0x000f0010 Any idea what the problem can be ? I've already spent my whole day on that, but... I'm stuck. Thanks in advance... Miky Mike Ok, Here is more then from the console, I get this : This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys002 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-17280-65 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… Error launching remote program: failed to get the task for process 456. Error launching remote program: failed to get the task for process 456. The program being debugged is not being run. The program being debugged is not being run. [Session started at 2010-12-23 20:33:33 +0100.] GNU gdb 6.3.50-20050815 (Apple version gdb-1472) (Thu Aug 5 05:54:10 UTC 2010) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys004 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-17280-72 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… Error launching remote program: failed to get the task for process 508. Error launching remote program: failed to get the task for process 508. The program being debugged is not being run. The program being debugged is not being run. And here is the code page that calls the URL import "TheLearningMachineAppDelegate.h" import "RootViewController.h" @implementation TheLearningMachineAppDelegate @synthesize window; @synthesize navigationController; pragma mark - pragma mark Application lifecycle (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { RootViewController *rootViewController = (RootViewController *)[navigationController topViewController]; rootViewController.managedObjectContext = self.managedObjectContext; [window addSubview:[navigationController view]]; [window makeKeyAndVisible]; return YES; } (void)applicationWillResignActive:(UIApplication )application { / Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state. Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game. */ } (void)applicationDidEnterBackground:(UIApplication *)application { [self saveContext]; } (void)applicationWillEnterForeground:(UIApplication )application { / Called as part of the transition from the background to the inactive state: here you can undo many of the changes made on entering the background. */ } (void)applicationDidBecomeActive:(UIApplication )application { / Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface. */ } // Method that saves the managed object context before the application terminates. (void)applicationWillTerminate:(UIApplication *)application { [self saveContext]; } (void)saveContext { NSError *error = nil; if (managedObjectContext != nil) { if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); //Replace this implementation with code to handle the error appropriately. //abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button. } } } pragma mark - pragma mark Core Data stack // Returns the managed object context for the application. (NSManagedObjectContext *)managedObjectContext { if (managedObjectContext != nil) { return managedObjectContext; } NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { managedObjectContext = [[NSManagedObjectContext alloc] init]; [managedObjectContext setPersistentStoreCoordinator:coordinator]; } return managedObjectContext; } // Returns the managed object model for the application. (NSManagedObjectModel *)managedObjectModel { if (managedObjectModel != nil) { return managedObjectModel; } NSString *modelPath = [[NSBundle mainBundle] pathForResource:@"TheLearningMachine" ofType:@"momd"]; NSURL *modelURL = [NSURL fileURLWithPath:modelPath]; managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL]; return managedObjectModel; } pragma mark - pragma mark Application's Documents directory // Returns the path to the application's Documents directory. - (NSString *)applicationDocumentsDirectory { return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]; } // Returns the persistent store coordinator for the application. - (NSPersistentStoreCoordinator *)persistentStoreCoordinator { if (persistentStoreCoordinator != nil) { return persistentStoreCoordinator; } NSURL *storeURL = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"TheLearningMachine.sqlite"]]; NSError *error = nil; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } return persistentStoreCoordinator; } pragma mark - pragma mark Memory management (void)applicationDidReceiveMemoryWarning:(UIApplication )application { / Free up as much memory as possible by purging cached data objects that can be recreated (or reloaded from disk) later. */ } (void)dealloc { [managedObjectContext release]; [managedObjectModel release]; [persistentStoreCoordinator release]; [window release]; [super dealloc]; } @end

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@ContextConfiguration in Spring 3.0 give me No default constructor found

- by atomsfat

I have already do the test using AbstractDependencyInjectionSpringContextTests and it works but in spring 3 it is deprecated, so I decided to try @ContextConfiguration but spring say that default constructor is not found, I check and the class doesn't have any constructor. If I use this test spring give the object. package atoms.portales.servicios.impl; import atoms.portales.model.Cliente; import atoms.portales.servicios.ClienteService; import java.util.List; import javax.persistence.EntityManager; import org.springframework.test.AbstractDependencyInjectionSpringContextTests; /** * * @author tsalazar */ public class ClienteServiceImplDeTest extends AbstractDependencyInjectionSpringContextTests{ private ClienteService clienteService; public ClienteService getClienteService() { return clienteService; } public void setClienteService(ClienteService clienteService) { this.clienteService = clienteService; } public ClienteServiceImplDeTest(String testName) { super(testName); } @Override protected String[] getConfigLocations() { return new String[]{"PersistenceAppCtx.xml", "ServicesAppCtx.xml"}; } /** * Test of buscaCliente method, of class ClienteServiceImplDeTest. */ public void testBuscaCliente() { System.out.println("======================================="); System.out.println("buscaCliente"); String nombre = ""; System.out.println(clienteService); System.out.println("======================================="); } } But if I use this, spring say that default constructor is not found. package atoms.config.portales.servicios.impl; import atoms.portales.model.Cliente; import atoms.portales.servicios.ClienteService; import org.junit.runner.RunWith; import org.junit.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import org.springframework.test.context.transaction.TransactionConfiguration; import org.springframework.transaction.annotation.Transactional; /** * * @author tsalazar */ @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(locations = {"/PersistenceAppCtx.xml", "/ServicesAppCtx.xml"}) @TransactionConfiguration(transactionManager = "transactionManager") @Transactional public class ClienteServiceImplTest { @Autowired private ClienteService clienteService; /** * Test of buscaCliente method, of class ClienteServiceImpl. */ @Test public void testBuscaCliente() { System.out.println("======================================="); System.out.println("buscaCliente"); System.out.println(clienteService); System.out.println("======================================="); } } This how I do the implementacion: package atoms.portales.servicios; import atoms.portales.model; /** * Una interface para obtener clientes, con sus surcursales, servicios, layouts * y contratos. Tambien soporta operaciones CRUD. * @author tsalazar */ public interface ClienteService { /** * Busca clientes a partir del nombre * @param nombre */ public Cliente buscaCliente(String nombre); } the implemetacion package atoms.portales..servicios.impl; import atoms.portales.model.Cliente; import atoms.portales.servicios.ClienteService; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import org.springframework.stereotype.Repository; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; /** * A JPA-based implementation.Delegates to a JPA entity manager to issue data access calls * against the backing repository. The EntityManager reference is provided by the managing container (Spring) * automatically. */ @Service("clienteSerivice") @Repository public class ClienteServiceImpl implements ClienteService { public ClienteServiceImpl() { } private EntityManager em; @PersistenceContext public void setEntityManager(EntityManager em) { this.em = em; } @Transactional(readOnly = true) public Cliente buscaCliente(String nombre) { Cliente cliente = em.getReference(Cliente.class, 1l); return cliente; } } spring configuration: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">  <tx:annotation-driven />  <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean>  <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" /> </property> </bean>  <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="org.hsqldb.jdbcDriver" /> <property name="url" value="jdbc:hsqldb:hsql://localhost/test" /> <property name="username" value="sa" /> <property name="password" value="" /> </bean> <context:component-scan base-package="atoms.portales.servicios" /> </beans> This is the persistence.xml <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="configuradorPortales" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <class>atoms.portales.model.Cliente</class> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="create-drop"/> <property name="hibernate.show_sql" value="true"/> <property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider"/> </properties> </persistence-unit> </persistence> This is the error that give me:

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Committed JDO writes do not apply on local GAE HRD, or possibly reused transaction

- by eeeeaaii

I'm using JDO 2.3 on app engine. I was using the Master/Slave datastore for local testing and recently switched over to using the HRD datastore for local testing, and parts of my app are breaking (which is to be expected). One part of the app that's breaking is where it sends a lot of writes quickly - that is because of the 1-second limit thing, it's failing with a concurrent modification exception. Okay, so that's also to be expected, so I have the browser retry the writes again later when they fail (maybe not the best hack but I'm just trying to get it working quickly). But a weird thing is happening. Some of the writes which should be succeeding (the ones that DON'T get the concurrent modification exception) are also failing, even though the commit phase completes and the request returns my success code. I can see from the log that the retried requests are working okay, but these other requests that seem to have committed on the first try are, I guess, never "applied." But from what I read about the Apply phase, writing again to that same entity should force the apply... but it doesn't. Code follows. Some things to note: I am attempting to use automatic JDO caching. So this is where JDO uses memcache under the covers. This doesn't actually work unless you wrap everything in a transaction. all the requests are doing is reading a string out of an entity, modifying part of the string, and saving that string back to the entity. If these requests weren't in transactions, you'd of course have the "dirty read" problem. But with transactions, isolation is supposed to be at the level of "serializable" so I don't see what's happening here. the entity being modified is a root entity (not in a group) I have cross-group transactions enabled Another weird thing is happening. If the concurrent modification thing happens, and I subsequently edit more than 5 more entities (this is the max for cross-group transactions), then nothing happens right away, but when I stop and restart the server I get "IllegalArgumentException: operating on too many entity groups in a single transaction". Could it be possible that the PMF is returning the same PersistenceManager every time, or the PM is reusing the same transaction every time? I don't see how I could possibly get the above error otherwise. The code inside the transaction just edits one root entity. I can't think of any other way that GAE would give me the "too many entity groups" error. The relevant code (this is a simplified version) PersistenceManager pm = PMF.getManager(); Transaction tx = pm.currentTransaction(); String responsetext = ""; try { tx.begin(); // I have extra calls to "makePersistent" because I found that relying // on pm.close didn't always write the objects to cache, maybe that // was only a DataNucleus 1.x issue though Key userkey = obtainUserKeyFromCookie(); User u = pm.getObjectById(User.class, userkey); pm.makePersistent(u); // to make sure it gets cached for next time Key mapkey = obtainMapKeyFromQueryString(); // this is NOT a java.util.Map, just FYI Map currentmap = pm.getObjectById(Map.class, mapkey); Text mapData = currentmap.getMapData(); // mapData is JSON stored in the entity Text newMapData = parseModifyAndReturn(mapData); // transform the map currentmap.setMapData(newMapData); // mutate the Map object pm.makePersistent(currentmap); // make sure to persist so there is a cache hit tx.commit(); responsetext = "OK"; } catch (JDOCanRetryException jdoe) { // log jdoe responsetext = "RETRY"; } catch (Exception e) { // log e responsetext = "ERROR"; } finally { if (tx.isActive()) { tx.rollback(); } pm.close(); } resp.getWriter().println(responsetext); EDIT: so I have verified that it fails after exactly 5 transactions. Here's what I do: I create a Foo (root entity), do a bunch of concurrent operations on that Foo, and some fail and get retried, and some commit but don't apply (as described above). Then, I start creating more Foos, and do a few operations on those new Foos. If I only create four Foos, stopping and restarting app engine does NOT give me the IllegalArgumentException. However if I create five Foos (which is the limit for cross-group transactions), then when I stop and restart app engine, I do get the exception. So it seems that somehow these new Foos I am creating are counting toward the limit of 5 max entities per transaction, even though they are supposed to be handled by separate transactions. It's as if a transaction is still open and is being reused by the servlet when it handles the new requests for the 2nd through 5th Foos. EDIT2: it looks like the IllegalArgument thing is independent of the other bug. In other words, it always happens when I create five Foos, even if I don't get the concurrent modification exception. I don't know if it's a symptom of the same problem or if it's unrelated. EDIT3: I found out what was causing the (unrelated) IllegalArgumentException, it was a dumb mistake on my part. But the other issue is still happening. EDIT4: added pseudocode for the datastore access EDIT5: I am pretty sure I know why this is happening, but I will still award the bounty to anyone who can confirm it. Basically, I think the problem is that transactions are not really implemented in the local version of the datastore. References: https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/gVMS1dFSpcU https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/deGasFdIO-M https://groups.google.com/forum/?hl=en&fromgroups=#!msg/google-appengine-java/4YuNb6TVD6I/gSttMmHYwo0J Because transactions are not implemented, rollback is essentially a no-op. Therefore, I get a dirty read when two transactions try to modify the record at the same time. In other words, A reads the data and B reads the data at the same time. A attempts to modify the data, and B attempts to modify a different part of the data. A writes to the datastore, then B writes, obliterating A's changes. Then B is "rolled back" by app engine, but since rollbacks are a no-op when running on the local datastore, B's changes stay, and A's do not. Meanwhile, since B is the thread that threw the exception, the client retries B, but does not retry A (since A was supposedly the transaction that succeeded).

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wrong return value with jquery ajax and codeigniter

- by matthew

I do not know if this is specifically a jquery problem, actually I think it has to mostly do with my logic in the php code. What Im trying to do is make a voting system that when the user clicks on the vote up or vote down link in the web page, it triggers an ajax call to a php function that first updates the database with with the required value, on success of the database updating the another function is called just to get the required updated html for the that particular post that the user has voted on. (hope I havnt lost you). The problem I think deals with specifically with this one line of code. When I make the call it only returns the value of $row-beer_down and completly ignores everything else in that line. Funny thing is the same php code to display the html view works perfectly before the ajax function updates it. echo "<p>Score " . $row->beer_up + $row->beer_down . "</p>"; so here is the code to hope you can help as I have absolutely no idea how to fix this. here is the view file where it generates the page. This part is the query ajax function. <script type="text/javascript"> $(function() { $(".vote").click(function(){ var id = $(this).attr("id"); var name = $(this).attr("name"); var dataString = 'id='+ id ; var parent = $(this); if(name=='up') { $.ajax({ type: "POST", url: "http://127.0.0.1/CodeIgniter/blog/add_vote/" + id, data: dataString, cache: false, success: function(html) { //parent.html(html); $("." + id).load('http://127.0.0.1/CodeIgniter/blog/get_post/' + id).fadeIn("slow"); } }); } else { $.ajax({ type: "POST", url: "http://127.0.0.1/CodeIgniter/blog/minus_vote/" + id, data: dataString, cache: false, success: function(html) { //parent.html(html); $("." + id).load('http://127.0.0.1/CodeIgniter/blog/get_post/' + id).fadeIn("slow"); } }); } return false; }); }); </script> Here is the html and php part of the page to display the post. div id="post_container"> <?php //echo $this->table->generate($records); ?> <?php foreach($records->result() as $row) { ?> <?php echo "<div id=\"post\" class=\"" . $row->id . "\">"; ?> <h2><?php echo $row->id ?></h2> <?php echo "<img src=\"" . base_url() . $dir . $row->account_id . "/" . $row->file_name . "\">" ?> <p><?php echo $row->content ?></p> <p><?php echo $row->user_name ?> On <?php echo $row->time ?></p> <p>Score <?php echo $row->beer_up + $row->beer_down ?></p> <?php echo anchor('blog/add_vote/' . $row->id, 'Up Vote', array('class' => 'vote', 'id' => $row->id, 'name' => 'up')); echo anchor('blog/minus_vote/' . $row->id, 'Down Vote', array('class' => 'vote', 'id' => $row->id, 'name' => 'down')); echo anchor('blog/comments/' . $row->id, 'View Comments'); ?> </div> <?php } ?> here is the function the ajax calls when it is successfull: function get_post() { $this->db->where('id', $this->uri->segment(3)); $records = $this->db->get('post'); $dir = "/uploads/user_uploads/"; foreach($records->result() as $row) { echo "<div id=\"post\" class=\"" . $row->id . "\">"; echo "<h2>" . $row->id . "</h2>"; echo "<img src=\"" . base_url() . $dir . $row->account_id . "/" . $row->file_name . "\">"; echo "<p>" . $row->content . "</p>"; echo "<p>" . $row->user_name . " On " . $row->time . "</p>"; echo "<p>Score " . $row->beer_up + $row->beer_down . "</p>"; echo "<p>Up score" . $row->beer_up . "beer down" . $row->beer_down . "</p>"; echo anchor('blog/comments/' . $row->id, 'View Comments'); echo "</div>"; }

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