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Ten - oh, wait, eleven - Eleven things you should know about the ASP.NET Fall 2012 Update

- by Jon Galloway

Today, just a little over two months after the big ASP.NET 4.5 / ASP.NET MVC 4 / ASP.NET Web API / Visual Studio 2012 / Web Matrix 2 release, the first preview of the ASP.NET Fall 2012 Update is out. Here's what you need to know: There are no new framework bits in this release - there's no change or update to ASP.NET Core, ASP.NET MVC or Web Forms features. This means that you can start using it without any updates to your server, upgrade concerns, etc. This update is really an update to the project templates and Visual Studio tooling, conceptually similar to the ASP.NET MVC 3 Tools Update. It's a relatively lightweight install. It's a 41MB download. I've installed it many times and usually takes 5-7 minutes; it's never required a reboot. It adds some new project templates to ASP.NET MVC: Facebook Application and Single Page Application templates. It adds a lot of cool enhancements to ASP.NET Web API. It adds some tooling that makes it easy to take advantage of features like SignalR, Friendly URLs, and Windows Azure Authentication. Most of the new features are installed via NuGet packages. Since ASP.NET is open source, nightly NuGet packages are available, and the roadmap is published, most of this has really been publicly available for a while. The official name of this drop is the ASP.NET Fall 2012 Update BUILD Prerelease. Please do not attempt to say that ten times fast. While the EULA doesn't prohibit it, it WILL legally change your first name to Scott. As with all new releases, you can find out everything you need to know about the Fall Update at http://asp.net/vnext (especially the release notes!) I'm going to be showing all of this off, assisted by special guest code monkey Scott Hanselman, this Friday at BUILD: Bleeding edge ASP.NET: See what is next for MVC, Web API, SignalR and more… (and I've heard it will be livestreamed). Let's look at some of those things in more detail. No new bits ASP.NET 4.5, MVC 4 and Web API have a lot of great core features. I see the goal of this update release as making it easier to put those features to use to solve some useful scenarios by taking advantage of NuGet packages and template code. If you create a new ASP.NET MVC application using one of the new templates, you'll see that it's using the ASP.NET MVC 4 RTM NuGet package (4.0.20710.0): This means you can install and use the Fall Update without any impact on your existing projects and no worries about upgrading or compatibility. New Facebook Application Template ASP.NET MVC 4 (and ASP.NET 4.5 Web Forms) included the ability to authenticate your users via OAuth and OpenID, so you could let users log in to your site using a Facebook account. One of the new changes in the Fall Update is a new template that makes it really easy to create full Facebook applications. You could create Facebook application in ASP.NET already, you'd just need to go through a few steps: Search around to find a good Facebook NuGet package, like the Facebook C# SDK (written by my friend Nathan Totten and some other Facebook SDK brainiacs). Read the Facebook developer documentation to figure out how to authenticate and integrate with them. Write some code, debug it and repeat until you got something working. Get started with the application you'd originally wanted to write. What this template does for you: eliminate steps 1-3. Erik Porter, Nathan and some other experts built out the Facebook Application template so it automatically pulls in and configures the Facebook NuGet package and makes it really easy to take advantage of it in an ASP.NET MVC application. One great example is the the way you access a Facebook user's information. Take a look at the following code in a File / New / MVC / Facebook Application site. First, the Home Controller Index action: [FacebookAuthorize(Permissions = "email")] public ActionResult Index(MyAppUser user, FacebookObjectList<MyAppUserFriend> userFriends) { ViewBag.Message = "Modify this template to jump-start your Facebook application using ASP.NET MVC."; ViewBag.User = user; ViewBag.Friends = userFriends.Take(5); return View(); } First, notice that there's a FacebookAuthorize attribute which requires the user is authenticated via Facebook and requires permissions to access their e-mail address. It binds to two things: a custom MyAppUser object and a list of friends. Let's look at the MyAppUser code: using Microsoft.AspNet.Mvc.Facebook.Attributes; using Microsoft.AspNet.Mvc.Facebook.Models; // Add any fields you want to be saved for each user and specify the field name in the JSON coming back from Facebook // https://developers.facebook.com/docs/reference/api/user/ namespace MvcApplication3.Models { public class MyAppUser : FacebookUser { public string Name { get; set; } [FacebookField(FieldName = "picture", JsonField = "picture.data.url")] public string PictureUrl { get; set; } public string Email { get; set; } } } You can add in other custom fields if you want, but you can also just bind to a FacebookUser and it will automatically pull in the available fields. You can even just bind directly to a FacebookUser and check for what's available in debug mode, which makes it really easy to explore. For more information and some walkthroughs on creating Facebook applications, see: Deploying your first Facebook App on Azure using ASP.NET MVC Facebook Template (Yao Huang Lin) Facebook Application Template Tutorial (Erik Porter) Single Page Application template Early releases of ASP.NET MVC 4 included a Single Page Application template, but it was removed for the official release. There was a lot of interest in it, but it was kind of complex, as it handled features for things like data management. The new Single Page Application template that ships with the Fall Update is more lightweight. It uses Knockout.js on the client and ASP.NET Web API on the server, and it includes a sample application that shows how they all work together. I think the real benefit of this application is that it shows a good pattern for using ASP.NET Web API and Knockout.js. For instance, it's easy to end up with a mess of JavaScript when you're building out a client-side application. This template uses three separate JavaScript files (delivered via a Bundle, of course): todoList.js - this is where the main client-side logic lives todoList.dataAccess.js - this defines how the client-side application interacts with the back-end services todoList.bindings.js - this is where you set up events and overrides for the Knockout bindings - for instance, hooking up jQuery validation and defining some client-side events This is a fun one to play with, because you can just create a new Single Page Application and hit F5. Quick, easy install (with one gotcha) One of the cool engineering changes for this release is a big update to the installer to make it more lightweight and efficient. I've been running nightly builds of this for a few weeks to prep for my BUILD demos, and the install has been really quick and easy to use. The install takes about 5 minutes, has never required a reboot for me, and the uninstall is just as simple. There's one gotcha, though. In this preview release, you may hit an issue that will require you to uninstall and re-install the NuGet VSIX package. The problem comes up when you create a new MVC application and see this dialog: The solution, as explained in the release notes, is to uninstall and re-install the NuGet VSIX package: Start Visual Studio 2012 as an Administrator Go to Tools->Extensions and Updates and uninstall NuGet. Close Visual Studio Navigate to the ASP.NET Fall 2012 Update installation folder: For Visual Studio 2012: Program Files\Microsoft ASP.NET\ASP.NET Web Stack\Visual Studio 2012 For Visual Studio 2012 Express for Web: Program Files\Microsoft ASP.NET\ASP.NET Web Stack\Visual Studio Express 2012 for Web Double click on the NuGet.Tools.vsix to reinstall NuGet This took me under a minute to do, and I was up and running. ASP.NET Web API Update Extravaganza! Uh, the Web API team is out of hand. They added a ton of new stuff: OData support, Tracing, and API Help Page generation. OData support Some people like OData. Some people start twitching when you mention it. If you're in the first group, this is for you. You can add a [Queryable] attribute to an API that returns an IQueryable<Whatever> and you get OData query support from your clients. Then, without any extra changes to your client or server code, your clients can send filters like this: /Suppliers?$filter=Name eq ‘Microsoft’ For more information about OData support in ASP.NET Web API, see Alex James' mega-post about it: OData support in ASP.NET Web API ASP.NET Web API Tracing Tracing makes it really easy to leverage the .NET Tracing system from within your ASP.NET Web API's. If you look at the \App_Start\WebApiConfig.cs file in new ASP.NET Web API project, you'll see a call to TraceConfig.Register(config). That calls into some code in the new \App_Start\TraceConfig.cs file: public static void Register(HttpConfiguration configuration) { if (configuration == null) { throw new ArgumentNullException("configuration"); } SystemDiagnosticsTraceWriter traceWriter = new SystemDiagnosticsTraceWriter() { MinimumLevel = TraceLevel.Info, IsVerbose = false }; configuration.Services.Replace(typeof(ITraceWriter), traceWriter); } As you can see, this is using the standard trace system, so you can extend it to any other trace listeners you'd like. To see how it works with the built in diagnostics trace writer, just run the application call some API's, and look at the Visual Studio Output window: iisexpress.exe Information: 0 : Request, Method=GET, Url=http://localhost:11147/api/Values, Message='http://localhost:11147/api/Values' iisexpress.exe Information: 0 : Message='Values', Operation=DefaultHttpControllerSelector.SelectController iisexpress.exe Information: 0 : Message='WebAPI.Controllers.ValuesController', Operation=DefaultHttpControllerActivator.Create iisexpress.exe Information: 0 : Message='WebAPI.Controllers.ValuesController', Operation=HttpControllerDescriptor.CreateController iisexpress.exe Information: 0 : Message='Selected action 'Get()'', Operation=ApiControllerActionSelector.SelectAction iisexpress.exe Information: 0 : Operation=HttpActionBinding.ExecuteBindingAsync iisexpress.exe Information: 0 : Operation=QueryableAttribute.ActionExecuting iisexpress.exe Information: 0 : Message='Action returned 'System.String[]'', Operation=ReflectedHttpActionDescriptor.ExecuteAsync iisexpress.exe Information: 0 : Message='Will use same 'JsonMediaTypeFormatter' formatter', Operation=JsonMediaTypeFormatter.GetPerRequestFormatterInstance iisexpress.exe Information: 0 : Message='Selected formatter='JsonMediaTypeFormatter', content-type='application/json; charset=utf-8'', Operation=DefaultContentNegotiator.Negotiate iisexpress.exe Information: 0 : Operation=ApiControllerActionInvoker.InvokeActionAsync, Status=200 (OK) iisexpress.exe Information: 0 : Operation=QueryableAttribute.ActionExecuted, Status=200 (OK) iisexpress.exe Information: 0 : Operation=ValuesController.ExecuteAsync, Status=200 (OK) iisexpress.exe Information: 0 : Response, Status=200 (OK), Method=GET, Url=http://localhost:11147/api/Values, Message='Content-type='application/json; charset=utf-8', content-length=unknown' iisexpress.exe Information: 0 : Operation=JsonMediaTypeFormatter.WriteToStreamAsync iisexpress.exe Information: 0 : Operation=ValuesController.Dispose API Help Page When you create a new ASP.NET Web API project, you'll see an API link in the header: Clicking the API link shows generated help documentation for your ASP.NET Web API controllers: And clicking on any of those APIs shows specific information: What's great is that this information is dynamically generated, so if you add your own new APIs it will automatically show useful and up to date help. This system is also completely extensible, so you can generate documentation in other formats or customize the HTML help as much as you'd like. The Help generation code is all included in an ASP.NET MVC Area: SignalR SignalR is a really slick open source project that was started by some ASP.NET team members in their spare time to add real-time communications capabilities to ASP.NET - and .NET applications in general. It allows you to handle long running communications channels between your server and multiple connected clients using the best communications channel they can both support - websockets if available, falling back all the way to old technologies like long polling if necessary for old browsers. SignalR remains an open source project, but now it's being included in ASP.NET (also open source, hooray!). That means there's real, official ASP.NET engineering work being put into SignalR, and it's even easier to use in an ASP.NET application. Now in any ASP.NET project type, you can right-click / Add / New Item... SignalR Hub or Persistent Connection. And much more... There's quite a bit more. You can find more info at http://asp.net/vnext, and we'll be adding more content as fast as we can. Watch my BUILD talk to see as I demonstrate these and other features in the ASP.NET Fall 2012 Update, as well as some other even futurey-er stuff!

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AJI Report #19 | Scott K Davis and his son Tommy on Gamification and Programming for Kids

- by Jeff Julian

We are very excited about this show. John and Jeff sat down with Scott Davis and his son Tommy to talk about Gamification and Programming for Kids. Tommy is nine years old and the Iowa Code Camp was his second time presenting. Scott and Tommy introduce a package called Scratch that was developed by MIT to teach kids about logic and interacting with programming using sprites. Tommy's favorite experience with programming right now is Lego Mindstorms because of the interaction with the Legos and the development. Most adults when they get started with development also got started with interacting more with the physical machines. The next generation is given amazing tools, but the tools tend to be sealed and the physical interaction is not there. With some of these alternative hobby platforms like Legos, Arduino, and .NET Micro Framework, kids can write some amazing application and see their code work with physical movement and interaction with devices and sensors. In the second half of this podcast, Scott talks about how companies can us Gamification to prompt employees to interact with software and processes in the organization. We see gamification throughout the consumer space and you need to do is open up the majority of the apps on our phones or tablets and there is some interaction point to give the user a reward for using the tool. Scott gets into his product Qonqr which is described as the board game Risk and Foursquare together. Scott gets into the different mindsets of gamers (Bartle Index) and how you can use these mindsets to get the most out of your team through gamification techniques. Listen to the Show Site: http://scottkdavis.com/ Twitter: @ScottKDavis LinkedIn: ScottKDavis Scratch: http://scratch.mit.edu/ Lego Mindstorms: http://mindstorms.lego.com/ Bartle Test: Wikipedia Gamification: Wikipedia

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Unable to install Google Chrome

- by Jordan

I receive this in my terminal when I try to install using wget https://dl.google.com/linux/direct/google-chrome-stable_current_i386.deb sudo dpkg -i google-chrome* or sudo dpkg --install /Path/to/chrome.deb I receive Selecting previously unselected package google-chrome-stable. (Reading database ... 146911 files and directories currently installed.) Unpacking google-chrome-stable (from google-chrome-stable_current_i386.deb) ... dpkg: dependency problems prevent configuration of google-chrome-stable: google-chrome-stable depends on xdg-utils (>= 1.0.2). dpkg: error processing google-chrome-stable (--install): dependency problems - leaving unconfigured Processing triggers for man-db ... Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Errors were encountered while processing: google-chrome-stable I then type sudo apt-get install -f And retry installation though it still does not install and I receive the same errors. I have also tried using: sudo apt-get install libxss1 libnspr4-0d libcurl3 Though the above doesn't work either.

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Google doesn't show "www" in results

- by tirengarfio

After searching my site on Google I have found that the URL that is shown doesn't contain www at the beginning, why? This is my virtualhost: <VirtualHost *:80> ServerName estebancortijo.com Redirect / http://www.estebancortijo.com/ </VirtualHost> <VirtualHost *:80> ServerName www.estebancortijo.com SetEnv MYAPP_ENV prod DocumentRoot /var/www/jesusesteban/web <Directory /var/www/jesusesteban/web/> # Options Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all <IfModule mod_mime.c> Addtype font/truetype .ttf AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css font/opentype font/truetype </IfModule> <IfModule mod_rewrite.c> Options -MultiViews RewriteEngine On #RewriteBase /path/to/app RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [QSA,L] </IfModule> <IfModule mod_expires.c> ExpiresActive On ExpiresDefault "access plus 10 days" ExpiresByType text/css "access plus 1 week" ExpiresByType text/plain "access plus 1 month" ExpiresByType image/gif "access plus 1 month" ExpiresByType image/png "access plus 1 month" ExpiresByType image/jpeg "access plus 1 month" ExpiresByType application/x-javascript "access plus 1 month" ExpiresByType application/javascript "access plus 1 week" ExpiresByType application/x-icon "access plus 1 year" </IfModule> </Directory> </VirtualHost> I have the same configuration for another site, but in that case the www is shown in Google results. Any idea?

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SQL SERVER – GUID vs INT – Your Opinion

- by pinaldave

I think the title is clear what I am going to write in your post. This is age old problem and I want to compile the list stating advantages and disadvantages of using GUID and INT as a Primary Key or Clustered Index or Both (the usual case). Let me start a list by suggesting one advantage and one disadvantage in each case. INT Advantage: Numeric values (and specifically integers) are better for performance when used in joins, indexes and conditions. Numeric values are easier to understand for application users if they are displayed. Disadvantage: If your table is large, it is quite possible it will run out of it and after some numeric value there will be no additional identity to use. GUID Advantage: Unique across the server. Disadvantage: String values are not as optimal as integer values for performance when used in joins, indexes and conditions. More storage space is required than INT. Please note that I am looking to create list of all the generic comparisons. There can be special cases where the stated information is incorrect, feel free to comment on the same. Please leave your opinion and advice in comment section. I will combine a final list and update this blog after a week. By listing your name in post, I will also give due credit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Constraint and Keys, SQL Data Storage, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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How to: Check which table is the biggest, in SQL Server

- by AngelEyes

The company I work with had it's DB double its size lately, so I needed to find out which tables were the biggest. I found this on the web, and decided it's worth remembering! Taken from http://www.sqlteam.com/article/finding-the-biggest-tables-in-a-database, the code is from http://www.sqlteam.com/downloads/BigTables.sql /************************************************************************************** * * BigTables.sql * Bill Graziano (SQLTeam.com) * [email protected] * v1.1 * **************************************************************************************/ DECLARE @id INT DECLARE @type CHARACTER(2) DECLARE @pages INT DECLARE @dbname SYSNAME DECLARE @dbsize DEC(15, 0) DECLARE @bytesperpage DEC(15, 0) DECLARE @pagesperMB DEC(15, 0) CREATE TABLE #spt_space ( objid INT NULL, ROWS INT NULL, reserved DEC(15) NULL, data DEC(15) NULL, indexp DEC(15) NULL, unused DEC(15) NULL ) SET nocount ON -- Create a cursor to loop through the user tables DECLARE c_tables CURSOR FOR SELECT id FROM sysobjects WHERE xtype = 'U' OPEN c_tables FETCH NEXT FROM c_tables INTO @id WHILE @@FETCH_STATUS = 0 BEGIN /* Code from sp_spaceused */ INSERT INTO #spt_space (objid, reserved) SELECT objid = @id, SUM(reserved) FROM sysindexes WHERE indid IN ( 0, 1, 255 ) AND id = @id SELECT @pages = SUM(dpages) FROM sysindexes WHERE indid < 2 AND id = @id SELECT @pages = @pages + Isnull(SUM(used), 0) FROM sysindexes WHERE indid = 255 AND id = @id UPDATE #spt_space SET data = @pages WHERE objid = @id /* index: sum(used) where indid in (0, 1, 255) - data */ UPDATE #spt_space SET indexp = (SELECT SUM(used) FROM sysindexes WHERE indid IN ( 0, 1, 255 ) AND id = @id) - data WHERE objid = @id /* unused: sum(reserved) - sum(used) where indid in (0, 1, 255) */ UPDATE #spt_space SET unused = reserved - (SELECT SUM(used) FROM sysindexes WHERE indid IN ( 0, 1, 255 ) AND id = @id) WHERE objid = @id UPDATE #spt_space SET ROWS = i.ROWS FROM sysindexes i WHERE i.indid < 2 AND i.id = @id AND objid = @id FETCH NEXT FROM c_tables INTO @id END SELECT TOP 25 table_name = (SELECT LEFT(name, 25) FROM sysobjects WHERE id = objid), ROWS = CONVERT(CHAR(11), ROWS), reserved_kb = Ltrim(Str(reserved * d.low / 1024., 15, 0) + ' ' + 'KB'), data_kb = Ltrim(Str(data * d.low / 1024., 15, 0) + ' ' + 'KB'), index_size_kb = Ltrim(Str(indexp * d.low / 1024., 15, 0) + ' ' + 'KB'), unused_kb = Ltrim(Str(unused * d.low / 1024., 15, 0) + ' ' + 'KB') FROM #spt_space, MASTER.dbo.spt_values d WHERE d.NUMBER = 1 AND d.TYPE = 'E' ORDER BY reserved DESC DROP TABLE #spt_space CLOSE c_tables DEALLOCATE c_tables

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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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SQLAuthority News – Happy Deepavali and Happy News Year

- by pinaldave

Diwali or Deepavali is popularly known as the festival of lights. It literally means “array of light” or “row of lamps“. Today we build a small clay maps and fill it with oil and light it up. The significance of lighting the lamp is the triumph of good over evil. I work every single day in a year but today I am spending my time with family and little one. I make sure that my daughter is aware of our culture and she learns to celebrate the festival with the same passion and values which I have. Every year on this day, I do not write a long blog post but rather write a small post with various SQL Tips and Tricks. After reading them you should quickly get back to your friends and family – it is the most important festival day. Here are a few tips and tricks: Take regular full backup of your database Avoid cursors if they can be replaced by set based process Keep your index maintenance script handy and execute them at intervals Consider Solid State Drive (SDD) for crucial database and tempdb placement Update statistics for OLTP transactions at intervals I guess that’s it for today. If you still have more time to learn. Here are few things you should consider. Get FREE Books by Sign up for tomorrow’s webcast by Rick Morelan Watch SQL in Sixty Seconds Series – FREE SQL Learning Read my earlier 2300+ articles Well, I am sure that will keep you busy for the rest of the day! Happy Diwali to All of You! Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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Need help with PHP web app bootstrapping error potentially related to Zend [migrated]

- by Matt Shepherd

I am trying to get a program called OpenFISMA running on an Ubuntu AMI in AWS. The app is not really coded on the Ubuntu platform, but I am in my comfort zone there, and have tried both CentOS and OpenSUSE (both are sort of "native" for the app) for getting it working with the same or worse results. So, why not just get it working on Ubuntu? Anyway, the app is found here: www.openfisma.org and an install guide is found here: https://openfisma.atlassian.net/wiki/display/030100/Installation+Guide The install guide kind of sucks. It doesn't list dependencies in any coherent way or provide much of any detail (does not even mention Zend once on the entire page) so I've done a lot of work to divine the information I do have. This page provided some dependency inf (though again, Zend is not mentioned once): https://openfisma.atlassian.net/wiki/display/PUBLIC/RPM+Management#RPMManagement-BasicOverviewofRPMPackages Anyway, I got all the way through the install (so far as I could reconstruct it). I am going to the login page for the first time, and there should be some sort of bootstrapping occurring when I load the page. (I am not a programmer so I have no idea what it is doing there.) Anyway, I get a message on the web page that says: "An exception occurred while bootstrapping the application." So, then I go look in /var/www/data/logs/php.log and find this message: [22-Oct-2013 17:29:18 UTC] PHP Fatal error: Uncaught exception 'Zend_Exception' with message 'No entry is registered for key 'Zend_Log'' in /var/www/library/Zend/Registry.php:147 Stack trace: #0 /var/www/public/index.php(188): Zend_Registry::get('Zend_Log') #1 {main} thrown in /var/www/library/Zend/Registry.php on line 147 This occurs every time I load the page. I gather there is an issue related to registering the Zend_Log variable in the Zend registry, but other than that I really have no idea what to do about it. Am I missing a package that it needs, or is this app not coded to register the variables properly? I have no clue. Any help is greatly appreciated. The application file referenced in the log message (index.php) is included below. <?php /** * Copyright (c) 2008 Endeavor Systems, Inc. * * This file is part of OpenFISMA. * * OpenFISMA is free software: you can redistribute it and/or modify it under the terms of the GNU General Public * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later * version. * * OpenFISMA is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more * details. * * You should have received a copy of the GNU General Public License along with OpenFISMA. If not, see * {@link http://www.gnu.org/licenses/}. */ try { defined('APPLICATION_PATH') || define( 'APPLICATION_PATH', realpath(dirname(__FILE__) . '/../application') ); // Define application environment defined('APPLICATION_ENV') || define( 'APPLICATION_ENV', (getenv('APPLICATION_ENV') ? getenv('APPLICATION_ENV') : 'production') ); set_include_path( APPLICATION_PATH . '/../library/Symfony/Components' . PATH_SEPARATOR . APPLICATION_PATH . '/../library' . PATH_SEPARATOR . get_include_path() ); require_once 'Fisma.php'; require_once 'Zend/Application.php'; $application = new Zend_Application( APPLICATION_ENV, APPLICATION_PATH . '/config/application.ini' ); Fisma::setAppConfig($application->getOptions()); Fisma::initialize(Fisma::RUN_MODE_WEB_APP); $application->bootstrap()->run(); } catch (Zend_Config_Exception $zce) { // A zend config exception indicates that the application may not be installed properly echo '<h1>The application is not installed correctly</h1>'; $zceMsg = $zce->getMessage(); if (stristr($zceMsg, 'parse_ini_file') !== false) { if (stristr($zceMsg, 'application.ini') !== false) { if (stristr($zceMsg, 'No such file or directory') !== false) { echo 'The ' . APPLICATION_PATH . '/config/application.ini file is missing.'; } elseif (stristr($zceMsg, 'Permission denied') !== false) { echo 'The ' . APPLICATION_PATH . '/config/application.ini file does not have the ' . 'appropriate permissions set for the application to read it.'; } else { echo 'An ini-parsing error has occured in ' . APPLICATION_PATH . '/config/application.ini ' . '<br/>Please check this file and make sure everything is setup correctly.'; } } else if (stristr($zceMsg, 'database.ini') !== false) { if (stristr($zceMsg, 'No such file or directory') !== false) { echo 'The ' . APPLICATION_PATH . '/config/database.ini file is missing.<br/>'; echo 'If you find a database.ini.template file in the config directory, edit this file ' . 'appropriately and rename it to database.ini'; } elseif (stristr($zceMsg, 'Permission denied') !== false) { echo 'The ' . APPLICATION_PATH . '/config/database.ini file does not have the appropriate ' . 'permissions set for the application to read it.'; } else { echo 'An ini-parsing error has occured in ' . APPLICATION_PATH . '/config/database.ini ' . '<br/>Please check this file and make sure everything is setup correctly.'; } } else { echo 'An ini-parsing error has occured. <br/>Please check all configuration files and make sure ' . 'everything is setup correctly'; } } elseif (stristr($zceMsg, 'syntax error') !== false) { if (stristr($zceMsg, 'application.ini') !== false) { echo 'There is a syntax error in ' . APPLICATION_PATH . '/config/application.ini ' . '<br/>Please check this file and make sure everything is setup correctly.'; } elseif (stristr($zceMsg, 'database.ini') !== false) { echo 'There is a syntax error in ' . APPLICATION_PATH . '/config/database.ini ' . '<br/>Please check this file and make sure everything is setup correctly.'; } else { echo 'A syntax error has been reached. <br/>Please check all configuration files and make sure ' . 'everything is setup correctly.'; } } else { // Then the exception message says nothing about parse_ini_file nor 'syntax error' echo 'Please check all configuration files, and ensure all settings are valid.'; } echo '<br/>For more information and help on installing OpenFISMA, please refer to the ' . '<a target="_blank" href="http://manual.openfisma.org/display/ADMIN/Installation">' . 'Installation Guide</a>'; } catch (Doctrine_Manager_Exception $dme) { echo '<h1>An exception occurred while bootstrapping the application.</h1>'; // Does database.ini have valid settings? Or is it the same content as database.ini.template? $databaseIniFail = false; $iniData = file(APPLICATION_PATH . '/config/database.ini'); $iniData = str_replace(chr(10), '', $iniData); if (in_array('db.adapter = ##DB_ADAPTER##', $iniData)) { $databaseIniFail = true; } if (in_array('db.host = ##DB_HOST##', $iniData)) { $databaseIniFail = true; } if (in_array('db.port = ##DB_PORT##', $iniData)) { $databaseIniFail = true; } if (in_array('db.username = ##DB_USER##', $iniData)) { $databaseIniFail = true; } if (in_array('db.password = ##DB_PASS##', $iniData)) { $databaseIniFail = true; } if (in_array('db.schema = ##DB_NAME##', $iniData)) { $databaseIniFail = true; } if ($databaseIniFail) { echo 'You have not applied the settings in ' . APPLICATION_PATH . '/config/database.ini appropriately. ' . 'Please review the contents of this file and try again.'; } else { if (Fisma::debug()) { echo '<p>' . get_class($dme) . '</p><p>' . $dme->getMessage() . '</p><p>' . "<p><pre>Stack Trace:\n" . $dme->getTraceAsString() . '</pre></p>'; } else { $logString = get_class($dme) . "\n" . $dme->getMessage() . "\nStack Trace:\n" . $dme->getTraceAsString() . "\n"; Zend_Registry::get('Zend_Log')->err($logString); } } } catch (Exception $exception) { // If a bootstrap exception occurs, that indicates a serious problem, such as a syntax error. // We won't be able to do anything except display an error. echo '<h1>An exception occurred while bootstrapping the application.</h1>'; if (Fisma::debug()) { echo '<p>' . get_class($exception) . '</p><p>' . $exception->getMessage() . '</p><p>' . "<p><pre>Stack Trace:\n" . $exception->getTraceAsString() . '</pre></p>'; } else { $logString = get_class($exception) . "\n" . $exception->getMessage() . "\nStack Trace:\n" . $exception->getTraceAsString() . "\n"; Zend_Registry::get('Zend_Log')->err($logString); } }

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Download Free Norton Antivirus 2012 with 6 months subscription

- by Gopinath

Norton, one of the most popular antivirus software Antivirus is now available as a free download with 6 months of subscription. Thanks to Facebook for teaming up with Symantec and providing Norton Antivirus 2012 for free to all its users. To grab your copy of Free antivirus, point your browser to http://us.norton.com/ps/loem/EN/Facebook/index.html and click on the download link. Without asking for any personal details or registration the download starts and you can follow the on screen instructions to install the antivirus. The antivirus is compatible with Windows PC and MAC OS. I tried installing on Windows 7 and the installation process started without any issues. But on Windows 8, the installer stopped after verifying the system requirements. The special offer also extends to Norton 360 which is available 50% discounted price. The original price for 1 year subscription of Norton 360 is around $90 and for Facebook users it’s available at $44.99. Update: Facebook is in partnership with many other antivirus vendors and providing antivirus software for free of cost. The other products are available for 6 months or more free subscription are: McAfee, Sophos Antivirus, Trend Micro. Please visit Facebook Security AV Market place for more details. Related: 5 Free Antivirus Applications For Windows

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What markup languages are good for programming articles/tutorials?

- by Vilx-

I very much wish to write a programming tutorial in my native language (Latvian). There are far too few of those. I am however unsure on what markup language to use for writing it. Here are a few things I would like to achieve: The same source can be compiled to both HTML for online viewing and printed form (PDF?). In HTML form it would allow superior interaction and appearance (see below), while the print form would look good on paper (layout etc). I have the idea that the tutorial could be multi-language. Different students have different requirements in their schools. For example, some schools teach Java, some teach C#. You could choose the language on the top of the HTML page and the relevant code snippets (and occasionally pieces of text) would swap out. Most of the text is the same anyway, only the language syntax is a bit different. The text would occasionally contain images too of course and these would need to be included in both the HTML and the printed version In the HTML version the code snippets should get automatic syntax coloring which should ideally be the same as in the recommended IDE for the tutorial. In case there are ambiguities, hints for the syntax colorer should be possible, but I don't want to do the whole coloring by hand. "Output" syntax coloring which would emulate a standard 80x25 text console (since many of the initial programs would be console applicatioins) Collapsible sections for answers to questions (aka "spoiler tags") Automatically generated index/table-of-contents Links to other parts of the tutorial (rendered as links in HTML and as references in print version) "Side note" sections, rendered as separate blocks on the side. Other functions useful in publications that I'm not aware of :) I know this is a bit much to ask, but is there something close enough that I could take it as a starting point and add the necessary features myself? Or is there something in the whole list (like the desire to have both HTML and print versions from the same source) that makes it all fundametally infeasible?

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Using a "white list" for extracting terms for Text Mining, Part 2

- by [email protected]

In my last post, we set the groundwork for extracting specific tokens from a white list using a CTXRULE index. In this post, we will populate a table with the extracted tokens and produce a case table suitable for clustering with Oracle Data Mining. Our corpus of documents will be stored in a database table that is defined as create table documents(id NUMBER, text VARCHAR2(4000)); However, any suitable Oracle Text-accepted data type can be used for the text. We then create a table to contain the extracted tokens. The id column contains the unique identifier (or case id) of the document. The token column contains the extracted token. Note that a given document many have many tokens, so there will be one row per token for a given document. create table extracted_tokens (id NUMBER, token VARCHAR2(4000)); The next step is to iterate over the documents and extract the matching tokens using the index and insert them into our token table. We use the MATCHES function for matching the query_string from my_thesaurus_rules with the text. DECLARE cursor c2 is select id, text from documents; BEGIN for r_c2 in c2 loop insert into extracted_tokens select r_c2.id id, main_term token from my_thesaurus_rules where matches(query_string, r_c2.text)>0; end loop; END; Now that we have the tokens, we can compute the term frequency - inverse document frequency (TF-IDF) for each token of each document. create table extracted_tokens_tfidf as with num_docs as (select count(distinct id) doc_cnt from extracted_tokens), tf as (select a.id, a.token, a.token_cnt/b.num_tokens token_freq from (select id, token, count(*) token_cnt from extracted_tokens group by id, token) a, (select id, count(*) num_tokens from extracted_tokens group by id) b where a.id=b.id), doc_freq as (select token, count(*) overall_token_cnt from extracted_tokens group by token) select tf.id, tf.token, token_freq * ln(doc_cnt/df.overall_token_cnt) tf_idf from num_docs, tf, doc_freq df where df.token=tf.token; From the WITH clause, the num_docs query simply counts the number of documents in the corpus. The tf query computes the term (token) frequency by computing the number of times each token appears in a document and divides that by the number of tokens found in the document. The doc_req query counts the number of times the token appears overall in the corpus. In the SELECT clause, we compute the tf_idf. Next, we create the nested table required to produce one record per case, where a case corresponds to an individual document. Here, we COLLECT all the tokens for a given document into the nested column extracted_tokens_tfidf_1. CREATE TABLE extracted_tokens_tfidf_nt NESTED TABLE extracted_tokens_tfidf_1 STORE AS extracted_tokens_tfidf_tab AS select id, cast(collect(DM_NESTED_NUMERICAL(token,tf_idf)) as DM_NESTED_NUMERICALS) extracted_tokens_tfidf_1 from extracted_tokens_tfidf group by id; To build the clustering model, we create a settings table and then insert the various settings. Most notable are the number of clusters (20), using cosine distance which is better for text, turning off auto data preparation since the values are ready for mining, the number of iterations (20) to get a better model, and the split criterion of size for clusters that are roughly balanced in number of cases assigned. CREATE TABLE km_settings (setting_name VARCHAR2(30), setting_value VARCHAR2(30)); BEGIN INSERT INTO km_settings (setting_name, setting_value) VALUES VALUES (dbms_data_mining.clus_num_clusters, 20); INSERT INTO km_settings (setting_name, setting_value) VALUES (dbms_data_mining.kmns_distance, dbms_data_mining.kmns_cosine); INSERT INTO km_settings (setting_name, setting_value) VALUES VALUES (dbms_data_mining.prep_auto,dbms_data_mining.prep_auto_off); INSERT INTO km_settings (setting_name, setting_value) VALUES VALUES (dbms_data_mining.kmns_iterations,20); INSERT INTO km_settings (setting_name, setting_value) VALUES VALUES (dbms_data_mining.kmns_split_criterion,dbms_data_mining.kmns_size); COMMIT; END; With this in place, we can now build the clustering model. BEGIN DBMS_DATA_MINING.CREATE_MODEL( model_name => 'TEXT_CLUSTERING_MODEL', mining_function => dbms_data_mining.clustering, data_table_name => 'extracted_tokens_tfidf_nt', case_id_column_name => 'id', settings_table_name => 'km_settings'); END;To generate cluster names from this model, check out my earlier post on that topic.

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Tile Engine - Procedural generation, Data structures, Rendering methods - A lot of effort question!

- by Trixmix

Isometric Tile and GameObject rendering. To achive the desired looking game I need to take into consideration which tiles need to be drawn first and which last. What I used is a Object that is TileRenderQueue that you would give it a tile list and it will give you a queue on which ones to draw based on their Z coordinate, so that if the Z is higher then it needs to be drawn last. Now if you read above you would know that I want the location data to instead of being stored in the tile instance i want it to be that the index in the array is the location. and then maybe based on the array i could draw the tiles instead of taking a long time in for looping and ordering them by Z. This is the hardest part for me. It's hard for me to find a simple solution to the which one to draw when problem. Also there is the fact that if the X is larger than the gameobject where the X is larger needs to be drawn over the rest of the tiles and so on. Here is an example: All the parts work together to create an efficient engine so its important to me that you would answer all of the parts. I hope you will work on the answers hard just as much that I worked on this question! If there is any unclear part tell me so in the comments! Thanks for the help!

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Are you aware of .NET Reflector Pro?

I'm sure many of my readers know Reflector, that tool to decompile the assemblies to see what it contains, maybe investigating what Microsoft has done with the base assemblies in .NET or maybe trying to understand 3rd party assemblies (or maybe just trying to recover the lost source code ;-) ) It's invaluable tool to have in your tool box. One nice scenario where it helps a lot is Sharepoint development in case you are in problems with the API. But are you aware that MS gave the product to Red Gate Software (http://www.red-gate.com) which released a Pro version of Reflector (http://www.red-gate.com/products/reflector/index.htm) a couple of months ago? Have a look at the feature set on top of the free version.Full support for .NET 1.0, 1.1, 2.0, 3.0, 3.5, and 4.0Decompile an entire assembly to either C# or VB to view and debug in Visual Studio Step-through debugging of any assembly in Visual Studio (as long as it's not obfuscated): Step into and set breakpoints anywhere in any assemblyWatch variables in the decompiled codeUse Visual Studio's advanced debugging features in decompiled code: Set Next Statement, modify variable values, and dynamic expression evaluation in the immediate window I strongly encourage you to have a look at .NET Reflector in case you haven't done so already. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Node.js Adventure - Node.js on Windows

- by Shaun

Two weeks ago I had had a talk with Wang Tao, a C# MVP in China who is currently running his startup company and product named worktile. He asked me to figure out a synchronization solution which helps his product in the future. And he preferred me implementing the service in Node.js, since his worktile is written in Node.js. Even though I have some experience in ASP.NET MVC, HTML, CSS and JavaScript, I don’t think I’m an expert of JavaScript. In fact I’m very new to it. So it scared me a bit when he asked me to use Node.js. But after about one week investigate I have to say Node.js is very easy to learn, use and deploy, even if you have very limited JavaScript skill. And I think I became love Node.js. Hence I decided to have a series named “Node.js Adventure”, where I will demonstrate my story of learning and using Node.js in Windows and Windows Azure. And this is the first one. (Brief) Introduction of Node.js I don’t want to have a fully detailed introduction of Node.js. There are many resource on the internet we can find. But the best one is its homepage. Node.js was created by Ryan Dahl, sponsored by Joyent. It’s consist of about 80% C/C++ for core and 20% JavaScript for API. It utilizes CommonJS as the module system which we will explain later. The official definition of Node.js is Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices. First of all, Node.js utilizes JavaScript as its development language and runs on top of V8 engine, which is being used by Chrome. It brings JavaScript, a client-side language into the backend service world. So many people said, even though not that actually, “Node.js is a server side JavaScript”. Additionally, Node.js uses an event-driven, non-blocking IO model. This means in Node.js there’s no way to block currently working thread. Every operation in Node.js executed asynchronously. This is a huge benefit especially if our code needs IO operations such as reading disks, connect to database, consuming web service, etc.. Unlike IIS or Apache, Node.js doesn’t utilize the multi-thread model. In Node.js there’s only one working thread serves all users requests and resources response, as the ST star in the figure below. And there is a POSIX async threads pool in Node.js which contains many async threads (AT stars) for IO operations. When a user have an IO request, the ST serves it but it will not do the IO operation. Instead the ST will go to the POSIX async threads pool to pick up an AT, pass this operation to it, and then back to serve any other requests. The AT will actually do the IO operation asynchronously. Assuming before the AT complete the IO operation there is another user comes. The ST will serve this new user request, pick up another AT from the POSIX and then back. If the previous AT finished the IO operation it will take the result back and wait for the ST to serve. ST will take the response and return the AT to POSIX, and then response to the user. And if the second AT finished its job, the ST will response back to the second user in the same way. As you can see, in Node.js there’s only one thread serve clients’ requests and POSIX results. This thread looping between the users and POSIX and pass the data back and forth. The async jobs will be handled by POSIX. This is the event-driven non-blocking IO model. The performance of is model is much better than the multi-threaded blocking model. For example, Apache is built in multi-threaded blocking model while Nginx is in event-driven non-blocking mode. Below is the performance comparison between them. And below is the memory usage comparison between them. These charts are captured from the video NodeJS Basics: An Introductory Training, which presented at Cloud Foundry Developer Advocate. Node.js on Windows To execute Node.js application on windows is very simple. First of you we need to download the latest Node.js platform from its website. After installed, it will register its folder into system path variant so that we can execute Node.js at anywhere. To confirm the Node.js installation, just open up a command windows and type “node”, then it will show the Node.js console. As you can see this is a JavaScript interactive console. We can type some simple JavaScript code and command here. To run a Node.js JavaScript application, just specify the source code file name as the argument of the “node” command. For example, let’s create a Node.js source code file named “helloworld.js”. Then copy a sample code from Node.js website. 1: var http = require("http"); 2: 3: http.createServer(function (req, res) { 4: res.writeHead(200, {"Content-Type": "text/plain"}); 5: res.end("Hello World\n"); 6: }).listen(1337, "127.0.0.1"); 7: 8: console.log("Server running at http://127.0.0.1:1337/"); This code will create a web server, listening on 1337 port and return “Hello World” when any requests come. Run it in the command windows. Then open a browser and navigate to http://localhost:1337/. As you can see, when using Node.js we are not creating a web application. In fact we are likely creating a web server. We need to deal with request, response and the related headers, status code, etc.. And this is one of the benefit of using Node.js, lightweight and straightforward. But creating a website from scratch again and again is not acceptable. The good news is that, Node.js utilizes CommonJS as its module system, so that we can leverage some modules to simplify our job. And furthermore, there are about ten thousand of modules available n the internet, which covers almost all areas in server side application development. NPM and Node.js Modules Node.js utilizes CommonJS as its module system. A module is a set of JavaScript files. In Node.js if we have an entry file named “index.js”, then all modules it needs will be located at the “node_modules” folder. And in the “index.js” we can import modules by specifying the module name. For example, in the code we’ve just created, we imported a module named “http”, which is a build-in module installed alone with Node.js. So that we can use the code in this “http” module. Besides the build-in modules there are many modules available at the NPM website. Thousands of developers are contributing and downloading modules at this website. Hence this is another benefit of using Node.js. There are many modules we can use, and the numbers of modules increased very fast, and also we can publish our modules to the community. When I wrote this post, there are totally 14,608 modules at NPN and about 10 thousand downloads per day. Install a module is very simple. Let’s back to our command windows and input the command “npm install express”. This command will install a module named “express”, which is a MVC framework on top of Node.js. And let’s create another JavaScript file named “helloweb.js” and copy the code below in it. I imported the “express” module. And then when the user browse the home page it will response a text. If the incoming URL matches “/Echo/:value” which the “value” is what the user specified, it will pass it back with the current date time in JSON format. And finally my website was listening at 12345 port. 1: var express = require("express"); 2: var app = express(); 3: 4: app.get("/", function(req, res) { 5: res.send("Hello Node.js and Express."); 6: }); 7: 8: app.get("/Echo/:value", function(req, res) { 9: var value = req.params.value; 10: res.json({ 11: "Value" : value, 12: "Time" : new Date() 13: }); 14: }); 15: 16: console.log("Web application opened."); 17: app.listen(12345); For more information and API about the “express”, please have a look here. Start our application from the command window by command “node helloweb.js”, and then navigate to the home page we can see the response in the browser. And if we go to, for example http://localhost:12345/Echo/Hello Shaun, we can see the JSON result. The “express” module is very populate in NPM. It makes the job simple when we need to build a MVC website. There are many modules very useful in NPM. - underscore: A utility module covers many common functionalities such as for each, map, reduce, select, etc.. - request: A very simple HTT request client. - async: Library for coordinate async operations. - wind: Library which enable us to control flow with plain JavaScript for asynchronous programming (and more) without additional pre-compiling steps. Node.js and IIS I demonstrated how to run the Node.js application from console. Since we are in Windows another common requirement would be, “can I host Node.js in IIS?” The answer is “Yes”. Tomasz Janczuk created a project IISNode at his GitHub space we can find here. And Scott Hanselman had published a blog post introduced about it. Summary In this post I provided a very brief introduction of Node.js, includes it official definition, architecture and how it implement the event-driven non-blocking model. And then I described how to install and run a Node.js application on windows console. I also described the Node.js module system and NPM command. At the end I referred some links about IISNode, an IIS extension that allows Node.js application runs on IIS. Node.js became a very popular server side application platform especially in this year. By leveraging its non-blocking IO model and async feature it’s very useful for us to build a highly scalable, asynchronously service. I think Node.js will be used widely in the cloud application development in the near future. In the next post I will explain how to use SQL Server from Node.js. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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When the canonical page itself changes url

- by lulalala

This is a continuation of the question: How to handle canonical url changes like Stack Overflow. Say I have the canon url: questions/11/car <---canonically-linked-from--- questions/11/ What will happen if I want to change the canon url to questions/11/car-with-sgx Obviously, questions/11/ will point to the new canon url. But how should the old questions/11/car change to the new one? There are two ways: 301 redirect that to new canon url the old canon url canonically link to the new canon url According to this post: [By using canonical link instead of redirect,] OldPage.html’s rankings will drop over time due to fewer internal links, but the canonical tag won’t make it disappear entirely. It could theoretically remain in their index until one of the following occurs: it is redirected permanently via 301 it returns a 404 for an extended period of time (they will keep checking for a while before dropping a URL) a meta robots “noindex” tag is added If this is true, I really need to use redirect from old canon url to the new canon url, which means I need to keep a log of previous old canon urls of this content, so I know when I can redirect. This is a bit of a hassle to do.

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SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

- by pinaldave

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

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PCSX2 1.0.0 installation issues

- by user205261

I've followed all the tutorials I can find to get this emulator to work and I'm now getting this error. Granted I've gotten a lot further than when I started. Running 13.10. Just downloaded the Linux download file from the pcsx2 website and did the following in terminal: jonathan@Assassin:~$ sudo add-apt-repository ppa:gregory-hainaut/pcsx2.official.ppa [sudo] password for jonathan: The Official pcsx2 ppa, provided by the pcsx2 team. This ppa contains a regular package snapshot of pcsx2. We are not package experts, but we try to follow the debian policy. Press [ENTER] to continue or ctrl-c to cancel adding it gpg: keyring `/tmp/tmpe5fwdz/secring.gpg' created gpg: keyring `/tmp/tmpe5fwdz/pubring.gpg' created gpg: requesting key 7A617FF4 from hkp server keyserver.ubuntu.com gpg: /tmp/tmpe5fwdz/trustdb.gpg: trustdb created gpg: key 7A617FF4: public key "Launchpad official ppa for pcsx2 team" imported gpg: Total number processed: 1 gpg: imported: 1 (RSA: 1) OK jonathan@Assassin:~$ sudo apt-get update Err http://ppa.launchpad.net saucy/main amd64 Packages 404 Not Found Err http://ppa.launchpad.net saucy/main i386 Packages 404 Not Found Fetched 67.4 kB in 16s (3,977 B/s) W: Failed to fetch ppa.launchpad.net/gregory-hainaut/pcsx2.official.ppa/ubuntu/dists/saucy/main/binary-amd64/Packages 404 Not Found W: Failed to fetch ppa.launchpad.net/gregory-hainaut/pcsx2.official.ppa/ubuntu/dists/saucy/main/binary-i386/Packages 404 Not Found E: Some index files failed to download. They have been ignored, or old ones used instead. jonathan@Assassin:~$ sudo apt-get install pcsx2 Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package pcsx2 So I'm assuming I just need the way to get the two missing packages?

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Oracle Coherence & Oracle Service Bus: REST API Integration

- by Nino Guarnacci

This post aims to highlight one of the features found in Oracle Coherence which allows it to be easily added and integrated inside a wider variety of projects. The features in question are the REST API exposed by the Coherence nodes, with which you can interact in the wider mode in memory data grid.Oracle Coherence and Oracle Service Bus are natively integrated through a feature found in the Oracle Service Bus, which allows you to use the coherence grid cache during the configuration phase of a business service. This feature allows you to use an intermediate layer of cache to retrieve the answers from previous invocations of the same service, without necessarily having to invoke the real business service again. Directly from the web console of Oracle Service Bus, you can decide the policies of eviction of the objects / answers and define the discriminating parameters that identify their uniqueness.The coherence REST APIs, however, allow you to integrate both products for other necessities enabling realization of new architectures design. Consider coherence’s node as a simple service which interoperates through the stardard services and in particular REST (with JSON and XML). Thinking of coherence as a company’s shared service, able to have an implementation of a centralized “map and reduce” which you can access by a huge variety of protocols (transport and envelopes).An amazing step forward for those who still imagine connectors and code. This type of integration does not require writing custom code or complex implementation to be self-supported. The added value is made unique by the incredible value of both products independently, and still more out of their simple and robust integration.As already mentioned this scenario discovers a hidden new door behind the columns of these two products. The door leads to new ideas and perspectives for enterprise architectures that increasingly wink to next-generation applications: simple and dynamic, perhaps towards the mobile and web 2.0.Below, a small and simple demo useful to demonstrate how easily is to integrate these two products using the Coherence REST API. This demo is also intended to imagine new enterprise architectures using this approach.The idea is to create a centralized system of alerting, fed easily from any company’s application, regardless of the technology with which they were built . Then use a representation standard protocol: RSS, using a service exposed by the service bus; So you can browse and search only the alerts that you are interested on, by category, author, title, date, etc etc.. The steps needed to implement this system are very simple and very few. Here they are listed below and described to be easily replicated within your environment. I would remind you that the demo is only meant to demonstrate how easily is to integrate Oracle Coherence and the Oracle Service Bus, and stimulate your imagination to new technological approaches.1) Install the two products: In this demo used (if necessary, consult the installation guides of 2 products) - Oracle Service Bus ver. 11.1.1.5.0 http://www.oracle.com/technetwork/middleware/service-bus/downloads/index.html - Oracle Coherence ver. 3.7.1 http://www.oracle.com/technetwork/middleware/coherence/downloads/index.html 2) Because you choose to create a centralized alerting system, we need to define a structure type containing some alerting attributes useful to preserve and organize the information of the various alerts sent by the different applications. Here, then it was built a java class named Alert containing the canonical properties of an alarm information:- Title- Description- System- Time- Severity 3) Therefore, we need to create two configuration files for the coherence node, in order to save the Alert objects within the grid, through the rest/http protocol (more than the native API for Java, C + +, C,. Net). Here are the two minimal configuration files for Coherence:coherence-rest-config.xml resty-server-config.xml This minimum configuration allows me to use a distributed cache named "alerts" that can also be accessed via http - rest on the host "localhost" over port "8080", objects are of type “oracle.cohsb.Alert”. 4) Below a simple Java class that represents the type of alert messages: 5) At this point we just need to startup our coherence node, able to listen on http protocol to manage the “alerts” cache, which will receive incoming XML or JSON objects of type Alert. Remember to include in the classpath of the coherence node, the Alert java class and the following coherence libraries and configuration files: At this point, just run the coherence class node “com.tangosol.net.DefaultCacheServer”advising you to set the following parameters:-Dtangosol.coherence.log.level=9 -Dtangosol.coherence.log=stdout -Dtangosol.coherence.cacheconfig=[PATH_TO_THE_FILE]\resty-server-config.xml 6) Let's create a procedure to test our configuration of Coherence and in order to insert some custom alerts in our cache. The technology with which you want to achieve this functionality is fully not considerable: Javascript, Python, Ruby, Scala, C + +, Java.... Because the protocol to communicate with Coherence is simply HTTP / JSON or XML. For this little demo i choose Java: A method to send/put the alert to the cache: A method to query and view the content of the cache: Finally the main method that execute our methods: No special library added in the classpath for our class (json struct static defined), when it will be executed, it asks some information such as title, description,... in order to compose and send an alert to the cache and then it will perform an inquiry, to the same cache. At this point, a good exercise at this point, may be to create the same procedure using other technologies, such as a simple html page containing some JavaScript code, and then using Python, Ruby, and so on.7) Now we are ready to start configuring the Oracle Service Bus in order to integrate the two products. First integrate the internal alerting system of Oracle Service Bus with our centralized alerting system based on coherence node. This ensures that by monitoring, or directly from within our Proxy Message Flow, we can throw alerts and save them directly into the Coherence node. To do this I choose to use the jms technology, natively present inside the Oracle Weblogic / Service Bus. Access to the Oracle WebLogic Administration console and create and configure a new JMS connection factory and a new jms destination (queue). Now we should create a new resource of type “alert destination” within our Oracle Service Bus project. The new “alert destination” resource should be configured using the newly created connection factory jms and jms destination. Finally, in order to withdraw the message alert enqueued in our JMS destination and send it to our coherence node, we just need to create a new business service and proxy service within our Oracle Service Bus project.Our business service is responsible for sending a message to our REST service Coherence using as a method action: PUT Finally our proxy service have to collect all messages enqueued on the destination, execute an xquery transformation on those messages in order to translate them into valid XML / alert objects useful to be sent to our coherence service, through the newly created business service. The message flow pipeline containing the xquery transformation: Incredibly, we just did a basic first integration between the native alerting system of Oracle Service Bus and our centralized alerting system by simply configuring our coherence node without developing anything.It's time to test it out. To do this I create a proxy service able to generate an alert using our "alert destination", whenever the proxy is invoked. After some invocation to our proxy that generates fake alerts, we could open an Internet browser and type the URL http://localhost: 8080/alerts/ so we could see what has been inserted within the coherence node. 8) We are ready for the final step. We would create a new message flow, that can be used to search and display the results in standard mode. To do this I choosen the standard representation of RSS, to display a formatted result on a huge variety of devices such as readers for the iPhone and Android. The inquiry may be defined already at the time of the request able to return only feed / items related to our needs. To do this we need to create a new business service, a new proxy service, and finally a new XQuery Transformation to take care of translating the collection of alerts that will be return from our coherence node in a nicely formatted RSS standard document.So we start right from this resource (xquery), which has the task of transforming a collection of alerts / xml returned from the node coherence in a type well-formatted feed RSS 2.0 our new business service that will search the alerts on our coherence node using the Rest API. And finally, our last resource, the proxy service that will be exposed as an RSS / feeds to various mobile devices and traditional web readers, in which we will intercept any search query, and transform the result returned by the business service in an RSS feed 2.0. The message flow with the transformation phase (Alert TO Feed Items): Finally some little tricks to follow during the routing to the business service, - check for any queries present in the url to require a subset of alerts - the http header "Accept" to help get an answer XML instead of JSON: In our little demo we also static added some coherence parameters to the request:sort=time:desc;start=0;count=100I would like to get from Coherence that the results will be sorted by date, and starting from 1 up to a maximum of 100.Done!!Just incredible, our centralized alerting system is ready. Inheriting all the qualities and capabilities of the two products involved Oracle Coherence & Oracle Service Bus: - RASP (Reliability, Availability, Scalability, Performance)Now try to use your mobile device, or a normal Internet browser by accessing the RSS just published: Some urls you may test: Search for the last 100 alerts : http://localhost:7001/alarmsSearch for alerts that do not have time set to null (time is not null):http://localhost:7001/alarms?q=time+is+not+nullSearch for alerts that the system property is “Web Browser” (system = ‘Web Browser’):http://localhost:7001/alarms?q=system+%3D+%27Web+Browser%27Search for alerts that the system property is “Web Browser” and the severity property is “Fatal” and the title property contain the word “Javascript” (system = ‘Web Broser’ and severity = ‘Fatal’ and title like ‘%Javascript%’)http://localhost:8080/alerts?q=system+%3D+%27Web+Browser%27+AND+severity+%3D+%27Fatal%27+AND+title+LIKE+%27%25Javascript%25%27 To compose more complex queries about your need I would suggest you to read the chapter in the coherence documentation inherent the Cohl language (Coherence Query Language) http://download.oracle.com/docs/cd/E24290_01/coh.371/e22837/api_cq.htm . Some useful links: - Oracle Coherence REST API Documentation http://download.oracle.com/docs/cd/E24290_01/coh.371/e22839/rest_intro.htm - Oracle Service Bus Documentation http://download.oracle.com/docs/cd/E21764_01/soa.htm#osb - REST explanation from Wikipedia http://en.wikipedia.org/wiki/Representational_state_transfer At this URL could be downloaded the whole materials of this demo http://blogs.oracle.com/slc/resource/cosb/coh-sb-demo.zip Author: Nino Guarnacci.

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Metro: Query Selectors

- by Stephen.Walther

The goal of this blog entry is to explain how to perform queries using selectors when using the WinJS library. In particular, you learn how to use the WinJS.Utilities.query() method and the QueryCollection class to retrieve and modify the elements of an HTML document. Introduction to Selectors When you are building a Web application, you need some way of easily retrieving elements from an HTML document. For example, you might want to retrieve all of the input elements which have a certain class. Or, you might want to retrieve the one and only element with an id of favoriteColor. The standard way of retrieving elements from an HTML document is by using a selector. Anyone who has ever created a Cascading Style Sheet has already used selectors. You use selectors in Cascading Style Sheets to apply formatting rules to elements in a document. For example, the following Cascading Style Sheet rule changes the background color of every INPUT element with a class of .required in a document to the color red: input.red { background-color: red } The “input.red” part is the selector which matches all INPUT elements with a class of red. The W3C standard for selectors (technically, their recommendation) is entitled “Selectors Level 3” and the standard is located here: http://www.w3.org/TR/css3-selectors/ Selectors are not only useful for adding formatting to the elements of a document. Selectors are also useful when you need to apply behavior to the elements of a document. For example, you might want to select a particular BUTTON element with a selector and add a click handler to the element so that something happens whenever you click the button. Selectors are not specific to Cascading Style Sheets. You can use selectors in your JavaScript code to retrieve elements from an HTML document. jQuery is famous for its support for selectors. Using jQuery, you can use a selector to retrieve matching elements from a document and modify the elements. The WinJS library enables you to perform the same types of queries as jQuery using the W3C selector syntax. Performing Queries with the WinJS.Utilities.query() Method When using the WinJS library, you perform a query using a selector by using the WinJS.Utilities.query() method. The following HTML document contains a BUTTON and a DIV element: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title>  <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script>  <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <button>Click Me!</button> <div style="display:none"> <h1>Secret Message</h1> </div> </body> </html> The document contains a reference to the following JavaScript file named \js\default.js: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.Utilities.query("button").listen("click", function () { WinJS.Utilities.query("div").clearStyle("display"); }); } }; app.start(); })(); The default.js script uses the WinJS.Utilities.query() method to retrieve all of the BUTTON elements in the page. The listen() method is used to wire an event handler to the BUTTON click event. When you click the BUTTON, the secret message contained in the hidden DIV element is displayed. The clearStyle() method is used to remove the display:none style attribute from the DIV element. Under the covers, the WinJS.Utilities.query() method uses the standard querySelectorAll() method. This means that you can use any selector which is compatible with the querySelectorAll() method when using the WinJS.Utilities.query() method. The querySelectorAll() method is defined in the W3C Selectors API Level 1 standard located here: http://www.w3.org/TR/selectors-api/ Unlike the querySelectorAll() method, the WinJS.Utilities.query() method returns a QueryCollection. We talk about the methods of the QueryCollection class below. Retrieving a Single Element with the WinJS.Utilities.id() Method If you want to retrieve a single element from a document, instead of matching a set of elements, then you can use the WinJS.Utilities.id() method. For example, the following line of code changes the background color of an element to the color red: WinJS.Utilities.id("message").setStyle("background-color", "red"); The statement above matches the one and only element with an Id of message. For example, the statement matches the following DIV element: <div id="message">Hello!</div> Notice that you do not use a hash when matching a single element with the WinJS.Utilities.id() method. You would need to use a hash when using the WinJS.Utilities.query() method to do the same thing like this: WinJS.Utilities.query("#message").setStyle("background-color", "red"); Under the covers, the WinJS.Utilities.id() method calls the standard document.getElementById() method. The WinJS.Utilities.id() method returns the result as a QueryCollection. If no element matches the identifier passed to WinJS.Utilities.id() then you do not get an error. Instead, you get a QueryCollection with no elements (length=0). Using the WinJS.Utilities.children() method The WinJS.Utilities.children() method enables you to retrieve a QueryCollection which contains all of the children of a DOM element. For example, imagine that you have a DIV element which contains children DIV elements like this: <div id="discussContainer"> <div>Message 1</div> <div>Message 2</div> <div>Message 3</div> </div> You can use the following code to add borders around all of the child DIV element and not the container DIV element: var discussContainer = WinJS.Utilities.id("discussContainer").get(0); WinJS.Utilities.children(discussContainer).setStyle("border", "2px dashed red"); It is important to understand that the WinJS.Utilities.children() method only works with a DOM element and not a QueryCollection. Notice that the get() method is used to retrieve the DOM element which represents the discussContainer. Working with the QueryCollection Class Both the WinJS.Utilities.query() method and the WinJS.Utilities.id() method return an instance of the QueryCollection class. The QueryCollection class derives from the base JavaScript Array class and adds several useful methods for working with HTML elements: addClass(name) – Adds a class to every element in the QueryCollection. clearStyle(name) – Removes a style from every element in the QueryCollection. conrols(ctor, options) – Enables you to create controls. get(index) – Retrieves the element from the QueryCollection at the specified index. getAttribute(name) – Retrieves the value of an attribute for the first element in the QueryCollection. hasClass(name) – Returns true if the first element in the QueryCollection has a certain class. include(items) – Includes a collection of items in the QueryCollection. listen(eventType, listener, capture) – Adds an event listener to every element in the QueryCollection. query(query) – Performs an additional query on the QueryCollection and returns a new QueryCollection. removeClass(name) – Removes a class from the every element in the QueryCollection. removeEventListener(eventType, listener, capture) – Removes an event listener from every element in the QueryCollection. setAttribute(name, value) – Adds an attribute to every element in the QueryCollection. setStyle(name, value) – Adds a style attribute to every element in the QueryCollection. template(templateElement, data, renderDonePromiseContract) – Renders a template using the supplied data. toggleClass(name) – Toggles the specified class for every element in the QueryCollection. Because the QueryCollection class derives from the base Array class, it also contains all of the standard Array methods like forEach() and slice(). Summary In this blog post, I’ve described how you can perform queries using selectors within a Windows Metro Style application written with JavaScript. You learned how to return an instance of the QueryCollection class by using the WinJS.Utilities.query(), WinJS.Utilities.id(), and WinJS.Utilities.children() methods. You also learned about the methods of the QueryCollection class.

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Manage a flexible and elastic Data Center with Oracle VM Manager (By Tarry Singh - PACKT Publishing)

- by frederic.michiara

For the ones looking at an easy reading and first good approach to Oracle VM Manager and VM Servers, I would recommend reading the following book even so it was written for 2.1.2 whereas we can use now Oracle VM 2.2 : Oracle VM Manager 2.1.2 Manage a Flexible and Elastic Data Center with Oracle VM Manager Learn quickly to install Oracle VM Manager and Oracle VM Servers Learn to manage your Virtual Data Center using Oracle VM Manager Import VMs from the Web, template, repositories, and other VM formats such as VMware Learn powerful Xen Hypervisor utilities such as xm, xentop, and virsh A practical hands-on book with step-by-step instructions Oracle VM experts might be frustrated, but to me it's not aim to Oracle VM experts, but to the ones who needs an introduction to the subject with a good coverage of all what you need to know. This book is available on https://www.packtpub.com/oracle-vm-manager-2-1-2/book Need to find out about Table of contents : https://www.packtpub.com/article/oracle-vm-manager-2-1-2-table-of-contents Discover a sample chapter : https://www.packtpub.com/sites/default/files/sample_chapters/7122-oracle-virtualization-sample-chapter-4-oracle-vm-management.pdf Read also articles from Tarry Singh on http://www.packtpub.com/ : Oracle VM Management : http://www.packtpub.com/article/oracle-vm-management-1 Extending Oracle VM Management : http://www.packtpub.com/article/oracle-vm-management-2 Hope you'll enjoy this book as a first approach to Oracle VM. For more information on Oracle VM : Oracle VM on n OTN : http://www.oracle.com/technology/products/vm/index.html Oracle VM Wiki : http://wiki.oracle.com/page/Oracle+VM Oracle VM on IBM System x : http://www-03.ibm.com/systems/x/solutions/infrastructure/erpcrm/oracle/virtualization.html

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Project Euler 53: Ruby

- by Ben Griswold

In my attempt to learn Ruby out in the open, here’s my solution for Project Euler Problem 53. I first attempted to solve this problem using the Ruby combinations libraries. That didn’t work out so well. With a second look at the problem, the provided formula ended up being just the thing to solve the problem effectively. As always, any feedback is welcome. # Euler 53 # http://projecteuler.net/index.php?section=problems&id=53 # There are exactly ten ways of selecting three from five, # 12345: 123, 124, 125, 134, 135, 145, 234, 235, 245, # and 345 # In combinatorics, we use the notation, 5C3 = 10. # In general, # # nCr = n! / r!(n-r)!,where r <= n, # n! = n(n1)...321, and 0! = 1. # # It is not until n = 23, that a value exceeds # one-million: 23C10 = 1144066. # In general: nCr # How many, not necessarily distinct, values of nCr, # for 1 <= n <= 100, are greater than one-million timer_start = Time.now # There's no factorial method in Ruby, I guess. class Integer # http://rosettacode.org/wiki/Factorial#Ruby def factorial (1..self).reduce(1, :*) end end def combinations(n, r) n.factorial / (r.factorial * (n-r).factorial) end answer = 0 100.downto(3) do |c| (2).upto(c-1) { |r| answer += 1 if combinations(c, r) > 1_000_000 } end puts answer puts "Elapsed Time: #{(Time.now - timer_start)*1000} milliseconds"

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Project Euler 51: Ruby

- by Ben Griswold

In my attempt to learn Ruby out in the open, here’s my solution for Project Euler Problem 51. I know I started back up with Python this week, but I have three more Ruby solutions in the hopper and I wanted to share. For the record, Project Euler 51 was the second hardest Euler problem for me thus far. Yeah. As always, any feedback is welcome. # Euler 51 # http://projecteuler.net/index.php?section=problems&id=51 # By replacing the 1st digit of *3, it turns out that six # of the nine possible values: 13, 23, 43, 53, 73, and 83, # are all prime. # # By replacing the 3rd and 4th digits of 56**3 with the # same digit, this 5-digit number is the first example # having seven primes among the ten generated numbers, # yielding the family: 56003, 56113, 56333, 56443, # 56663, 56773, and 56993. Consequently 56003, being the # first member of this family, is the smallest prime with # this property. # # Find the smallest prime which, by replacing part of the # number (not necessarily adjacent digits) with the same # digit, is part of an eight prime value family. timer_start = Time.now require 'mathn' def eight_prime_family(prime) 0.upto(9) do |repeating_number| # Assume mask of 3 or more repeating numbers if prime.count(repeating_number.to_s) >= 3 ctr = 1 (repeating_number + 1).upto(9) do |replacement_number| family_candidate = prime.gsub(repeating_number.to_s, replacement_number.to_s) ctr += 1 if (family_candidate.to_i).prime? end return true if ctr >= 8 end end false end # Wanted to loop through primes using Prime.each # but it took too long to get to the starting value. n = 9999 while n += 2 next if !n.prime? break if eight_prime_family(n.to_s) end puts n puts "Elapsed Time: #{(Time.now - timer_start)*1000} milliseconds"

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Why does apt-get fail to resolve the mirror?

- by Jake Kubisiak

I know this has been covered before, but I can't seem to resolve my issue. Here is my output. jake@KUBIE-SERVER:~$ sudo apt-get update Err http://us.archive.ubuntu.com precise InRelease Err http://us.archive.ubuntu.com precise-updates InRelease Err http://us.archive.ubuntu.com precise-backports InRelease Err http://security.ubuntu.com precise-security InRelease Err http://archive.canonical.com precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://archive.canonical.com precise Release.gpg Temporary failure resolving 'archive.canonical.com' Err http://ppa.launchpad.net precise Release.gpg Temporary failure resolving 'ppa.launchpad.net' Err http://security.ubuntu.com precise-security Release.gpg Temporary failure resolving 'security.ubuntu.com' Err http://us.archive.ubuntu.com precise Release.gpg Temporary failure resolving 'us.archive.ubuntu.com' Err http://us.archive.ubuntu.com precise-updates Release.gpg Temporary failure resolving 'us.archive.ubuntu.com' Err http://us.archive.ubuntu.com precise-backports Release.gpg Temporary failure resolving 'us.archive.ubuntu.com' Reading package lists... Done W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/InRelease W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise- updates/InRelease W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise- backports/InRelease W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/precise-security/InRelease W: Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/webupd8team/java/ubuntu/dists/precise/InRelease W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise/Release.gpg Temporary failure resolving 'us.archive.ubuntu.com' W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise- updates/Release.gpg Temporary failure resolving 'us.archive.ubuntu.com' W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise- backports/Release.gpg Temporary failure resolving 'us.archive.ubuntu.com' W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/precise- security/Release.gpg Temporary failure resolving 'security.ubuntu.com' W: Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/Release.gpg Temporary failure resolving 'archive.canonical.com' W: Failed to fetch http://ppa.launchpad.net/webupd8team/java/ubuntu/dists/precise/Release.gpg Temporary failure resolving 'ppa.launchpad.net' W: Some index files failed to download. They have been ignored, or old ones used instead. Any help is greatly appreciated.

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Phpmyadmin Not Working

- by glenbl54

I recently installed phpmyadmin onto ubuntu server 10.04 using sudo apt-get install phpmyadmin The installation went fine and everything was working including phpmyadmin. I then performed a restart of the server and now apache2 starts up but when I navigate to http://192.168.1.72/phpmyadmin/ I am getting a 403 error. I have included /etc/phpmyadmin/apache.conf file in /etc/apahe2/apache2.conf file /etc/phpmyadmin/apache.conf # phpMyAdmin default Apache configuration Alias /phpmyadmin /usr/share/phpmyadmin <Directory /usr/share/phpmyadmin> Options FollowSymLinks DirectoryIndex index.php <IfModule mod_php5.c> AddType application/x-httpd-php .php php_flag magic_quotes_gpc Off php_flag track_vars On php_flag register_globals Off php_value include_path . </IfModule> </Directory> # Authorize for setup <Directory /usr/share/phpmyadmin/setup> <IfModule mod_authn_file.c> AuthType Basic AuthName "phpMyAdmin Setup" AuthUserFile /etc/phpmyadmin/htpasswd.setup </IfModule> Require valid-user </Directory> #Disallow web access to directories that don't need it <Directory /usr/share/phpmyadmin/libraries> Order Deny,Allow Deny from All </Directory> <Directory /usr/share/phpmyadmin/setup/lib> Order Deny,Allow Deny from All </Directory> The only change that was made since phpmyadmin was installed was that timetrex was installed. Is there anyway to manually start phpmyadmin or should it already be working once apache started?

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