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  • Fair Comments

    - by Tony Davis
    To what extent is good code self-documenting? In one of the most entertaining sessions I saw at the recent PASS summit, Jeremiah Peschka (blog | twitter) got a laugh out of a sleepy post-lunch audience with the following remark: "Some developers say good code is self-documenting; I say, get off my team" I silently applauded the sentiment. It's not that all comments are useful, but that I mistrust the basic premise that "my code is so clearly written, it doesn't need any comments". I've read many pieces describing the road to self-documenting code, and my problem with most of them is that they feed the myth that comments in code are a sign of weakness. They aren't; in fact, used correctly I'd say they are essential. Regardless of how far intelligent naming can get you in describing what the code does, or how well any accompanying unit tests can explain to your fellow developers why it works that way, it's no excuse not to document fully the public interfaces to your code. Maybe I just mixed with the wrong crowd while learning my favorite language, but when I open a stored procedure I lose the will even to read it unless I see a big Phil Factor- or Jeff Moden-style header summarizing in plain English what the code does, how it fits in to the broader application, and a usage example. This public interface describes the high-level process and should explain the role of the code, clearly, for fellow developers, language non-experts, and even any non-technical stake holders in the project. When you step into the body of the code, the low-level details, then I agree that the rules are somewhat different; especially when code is subject to frequent refactoring that can quickly render comments redundant or misleading. At their worst, here, inline comments are sticking plaster to cover up the scars caused by poor naming conventions, failure in clarity when mapping a complex domain into code, or just by not entirely understanding the problem (/ this is the clever part). If you design and refactor your code carefully so that it is as simple as possible, your functions do one thing only, you avoid having two completely different algorithms in the same piece of code, and your functions, classes and variables are intelligently named, then, yes, the need for inline comments should be minimal. And yet, even given this, I'd still argue that many languages (T-SQL certainly being one) just don't lend themselves to readability when performing even moderately-complex tasks. If the algorithm is complex, I still like to see the occasional helpful comment. Please, therefore, be as liberal as you see fit in the detail of the comments you apply to this editorial, for like code it is bound to increase its' clarity and usefulness. Cheers, Tony.

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  • CodePlex Daily Summary for Wednesday, November 23, 2011

    CodePlex Daily Summary for Wednesday, November 23, 2011Popular ReleasesVisual Leak Detector for Visual C++ 2008/2010: v2.2.1: Enhancements: * strdup and _wcsdup functions support added. * Preliminary support for VS 11 added. Bugs Fixed: * Low performance after upgrading from VLD v2.1. * Memory leaks with static linking fixed (disabled calloc support). * Runtime error R6002 fixed because of wrong memory dump format. * version.h fixed in installer. * Some PVS studio warning fixed.NetSqlAzMan - .NET SQL Authorization Manager: 3.6.0.10: 3.6.0.10 22-Nov-2011 Update: Removed PreEmptive Platform integration (PreEmptive analytics) Removed all PreEmptive attributes Removed PreEmptive.dll assembly references from all projects Added first support to ADAM/AD LDS Thanks to PatBea. Work Item 9775: http://netsqlazman.codeplex.com/workitem/9775Developer Team Article System Management: DTASM v1.3: ?? ??? ???? 3 ????? ???? ???? ????? ??? : - ????? ?????? ????? ???? ?? ??? ???? ????? ?? ??? ? ?? ???? ?????? ???? ?? ???? ????? ?? . - ??? ?? ???? ????? ???? ????? ???? ???? ?? ????? , ?????? ????? ????? ?? ??? . - ??? ??????? ??? ??? ???? ?? ????? ????? ????? .SharePoint 2010 FBA Pack: SharePoint 2010 FBA Pack 1.2.0: Web parts are now fully customizable via html templates (Issue #323) FBA Pack is now completely localizable using resource files. Thank you David Chen for submitting the code as well as Chinese translations of the FBA Pack! The membership request web part now gives the option of having the user enter the password and removing the captcha (Issue # 447) The FBA Pack will now work in a zone that does not have FBA enabled (Another zone must have FBA enabled, and the zone must contain the me...SharePoint 2010 Education Demo Project: Release SharePoint SP1 for Education Solutions: This release includes updates to the Content Packs for SharePoint SP1. All Content Packs have been updated to install successfully under SharePoint SP1SQL Monitor - tracking sql server activities: SQLMon 4.1 alpha 6: 1. improved support for schema 2. added find reference when right click on object list 3. added object rename supportBugNET Issue Tracker: BugNET 0.9.126: First stable release of version 0.9. Upgrades from 0.8 are fully supported and upgrades to future releases will also be supported. This release is now compiled against the .NET 4.0 framework and is a requirement. Because of this the web.config has significantly changed. After upgrading, you will need to configure the authentication settings for user registration and anonymous access again. Please see our installation / upgrade instructions for more details: http://wiki.bugnetproject.c...Anno 2070 Assistant: v0.1.0 (STABLE): Version 0.1.0 Features Production Chains Eco Production Chains (Complete) Tycoon Production Chains (Disabled - Incomplete) Tech Production Chains (Disabled - Incomplete) Supply (Disabled - Incomplete) Calculator (Disabled - Incomplete) Building Layouts Eco Building Layouts (Complete) Tycoon Building Layouts (Disabled - Incomplete) Tech Building Layouts (Disabled - Incomplete) Credits (Complete)Free SharePoint 2010 Sites Templates: SharePoint Server 2010 Sites Templates: here is the list of sites templates to be downloadedVsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 30 Beta: Note: This release does not work with custom VsTortoise toolbars. These get removed every time when you shutdown Visual Studio. (#7940) Build 30 (beta)New: Support for TortoiseSVN 1.7 added. (the download contains both setups, for TortoiseSVN 1.6 and 1.7) New: OpenModifiedDocumentDialog displays conflicted files now. New: OpenModifiedDocument allows to group items by changelist now. Fix: OpenModifiedDocumentDialog caused Visual Studio 2010 to freeze sometimes. Fix: The installer didn...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.30: Highlight features & improvements: • Performance optimization. • Back in stock notifications. • Product special price support. • Catalog mode (based on customer role) To see the full list of fixes and changes please visit the release notes page (http://www.nopCommerce.com/releasenotes.aspx).WPF Converters: WPF Converters V1.2.0.0: support for enumerations, value types, and reference types in the expression converter's equality operators the expression converter now handles DependencyProperty.UnsetValue as argument values correctly (#4062) StyleCop conformance (more or less)Json.NET: Json.NET 4.0 Release 4: Change - JsonTextReader.Culture is now CultureInfo.InvariantCulture by default Change - KeyValurPairConverter no longer cares about the order of the key and value properties Change - Time zone conversions now use new TimeZoneInfo instead of TimeZone Fix - Fixed boolean values sometimes being capitalized when converting to XML Fix - Fixed error when deserializing ConcurrentDictionary Fix - Fixed serializing some Uris returning the incorrect value Fix - Fixed occasional error when...Media Companion: MC 3.423b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) Replaced 'Rebuild' with 'Refresh' throughout entire code. Rebuild will now be known as Refresh. mc_com.exe has been fully updated TV Show Resolutions... Resolved issue #206 - having to hit save twice when updating runtime manually Shrunk cache size and lowered loading times f...Delta Engine: Delta Engine Beta Preview v0.9.1: v0.9.1 beta release with lots of refactoring, fixes, new samples and support for iOS, Android and WP7 (you need a Marketplace account however). If you want a binary release for the games (like v0.9.0), just say so in the Forum or here and we will quickly prepare one. It is just not much different from v0.9.0, so I left it out this time. See http://DeltaEngine.net/Wiki.Roadmap for details.ASP.net Awesome Samples (Web-Forms): 1.0 samples: Demos and Tutorials for ASP.net Awesome VS2008 are in .NET 3.5 VS2010 are in .NET 4.0 (demos for the ASP.net Awesome jQuery Ajax Controls)SharpMap - Geospatial Application Framework for the CLR: SharpMap-0.9-AnyCPU-Trunk-2011.11.17: This is a build of SharpMap from the 0.9 development trunk as per 2011-11-17 For most applications the AnyCPU release is the recommended, but in case you need an x86 build that is included to. For some dataproviders (GDAL/OGR, SqLite, PostGis) you need to also referense the SharpMap.Extensions assembly For SqlServer Spatial you need to reference the SharpMap.SqlServerSpatial assemblyAJAX Control Toolkit: November 2011 Release: AJAX Control Toolkit Release Notes - November 2011 Release Version 51116November 2011 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4 - Binary – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 - Binary – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Notes: - The current version of the AJAX Control Toolkit is not compatible with ASP.NET 2.0. The latest version that is compatible with ASP.NET 2.0 can be found h...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.36: Fix for issue #16908: string literals containing ASP.NET replacement syntax fail if the ASP.NET code contains the same character as the string literal delimiter. Also, we shouldn't be changing the delimiter for those literals or combining them with other literals; the developer may have specifically chosen the delimiter used because of possible content inserted by ASP.NET code. This logic is normally off; turn it on via the -aspnet command-line flag (or the Code.Settings.AllowEmbeddedAspNetBl...MVC Controls Toolkit: Mvc Controls Toolkit 1.5.5: Added: Now the DateRanteAttribute accepts complex expressions containing "Now" and "Today" as static minimum and maximum. Menu, MenuFor helpers capable of handling a "currently selected element". The developer can choose between using a standard nested menu based on a standard SimpleMenuItem class or specifying an item template based on a custom class. Added also helpers to build the tree structure containing all data items the menu takes infos from. Improved the pager. Now the developer ...New ProjectsActiveWorlds World Server Admin PowerShell SnapIn: The purpose of this PowerShell SnapIn is to provide a set of tools to administer the world server from PowerShell. It leverages the ActiveWorlds SDK .NET Wrapper to provide this functionality.Aigu: Enter special characters like you would on your mobile phone. For instance, if you want to type 'é', you just hold down 'e' and a menu will appear. Selected the desired character using the arrow keys and press 'enter'. Simple but powerful.Are you workaholic?: Are you a workaholic? Did your Doctor advice you not to stare at the computer monitor for a long time? Then this app is perfectly made for you. It runs in the background, and alerts you to take periodic rests for your eyes and body. What's more, It's open source (MS-PL).ATDIS PoC: privateAuto Version Web Assets: The AVWA project is an HTTP Module written in C# that is designed to allow for versioning of various web assets such as .CSS and .JS files. This allows you to publish new versions of these files without having to force the server or the client browsers to expire cache.Bachelor Thesis Algorithm Test Bed: Algorithm Test Bed for my Bachelor ThesisBase64: Simple application helps converting strings and files from or to Base64 string. You can use any encoding to convert while a sidebar previews decoded string for all other encodings.BoracayExpress: BoracayExpressC++ Framework for Test Driven Development: A testing framework for C++ written in C++.Class2Table: Class2Table aka Entity2Table. Easy tool that allows creation of SQL tables from .Net types.Code for Demos & Experiments: This is where I will post code from demos and presentationsCodeMaker: CodeMaker?????????: 1、?????????? 2、???? 3、????? 4、??Python????????? ConsoleCommand: ConsoleCommand provides certain .Net commands for access from javascript console engines. Included are commands to set the text and background colors, as well as list and extract resources compiled in a .Net dll. Converter: Character code conversion tools ???????? CryptoInator - self contained, self-encrypting, self-decrypting image viewer: Original developed to encrypt and store NemID images in Denmark. DAiBears: Something, something, botDelicious Notify Plugin: Lets you push a blog post straight to Delicious from Live WriterDeveloperFile: Compresses Javascripts using the YUI .NET project. Loops through the root folder and subfolders for files matching the debug extension and creates new files using the release extension. (File extensions must match exactly).DotNetNuke SharePoint File Explorer: A DotNetNuke SharePoint File ExplorerDouban FM: WP7 Douban FM appGame Lib: Game Library is a open-source game library to allow focusing on the fun part of a game. It is developed in C#, but will be ported to C++ and VB.net.Google reader notes to Delicious Export tool (WPF): Google reader discontinued note in reader features. Current google reader allows to export users old notes in JSON format, This App will parse the JSON file & upload it to it delicious , delicious is a good alternative for note in readerHtml Source Transmitter Control: This web control allows getting a source of a web page, that will displayed before submit. So, developer can store a view of the html page, that was before server exception. It helps to reproduce bugs and can be used with other logging systems.Ideopuzzle: A puzzle gameImageShack-Uploader: This project demonstrates how to upload files automated to imageshack.us and other image hosters with C#.Insert Acronym Tags: Lets you insert <acronym> and <abbr> tags into your blog entry more easily.Insert Quick Link: Allows you to paste a link into the Writer window and have the a window similar to the one in Writer where you can change what text is to appear, open in new window, etc.Insert Video Plugin: Allows you to insert a video into a blog entry from a multitude of different sitesIoCWrap: Provides a wrapper to the various IoC container implementations so that it is possible to switch to a different provider without changing any application code.kaveepoj: sharepoint projectKinect Quiz Engine: Fun quiz game for the Kinect.Klaverjas: Test application for testing different new technologies in .NET (WCF, DataServices, C# stuff, Entity...etc.)Man In The Middle: A cyberpunk themed action with puzzle and strategy elements. Made with XNA as part of a game development course at the IT University of Copenhagen by Bo Bendtsen, Jonas Flensbak, Daniel Kromand, Jess Rahbek & Darryl Woodford.MediaSelektor: Simple tool to select mediasMicajah Mindtouch Deki Wiki Copier: Small C# application to move data between 2 Deki Wiki installs or, more importantly, from a wik.is account to a locally installed systemMineFlagger: MineFlagger is a mine clearing game modeled after Microsoft’s Minesweeper. In addition to standard play, MineFlagger incorporates an AI for fun and training.myXbyqwrhjadsfasfhgf: myXbyqwrhjadsfasfhgfnatoop: natoopNauplius.KeyStore: Provides secure application key storage backed by SQL 2008 and Active Directory.ObjectDB: An object database written using C# 4 and Mono.Cecil.PaceR: PaceR is an attempt to encapsulate a lot of the common code functionality I use on different projects. Instead of recreating functionality from memory or worse, copying from older projects, I'd like to have a central location to maintain this common code. Parseq: Parseq is a Parser Combinator library written in C# (version 2.0).PowerShell Network Adapter Configuration module: PowerShell Network Adapter Configuration module is a PowerShell module which provides functions for managing network adapters using WMI.public traffic tracker: This is a university project for a .net course. We develop a public traffic tracker applications for Windows Phone 7 devices, that can give information about the actual positions of the nearest vehicle on a given line. The speciality is that we use only the GPS information of the users' WP7 devices, so this is a completely software solution without any hardware investment. The disatvantage is that for the real operation we would need a lot of active WP7 user.puyo: puyoRadioTroll: Projeto web Radio TrollRead Feed Community: Read Feed CommunityReviewer: Reviewer.dk - Dansk spil og anmeldelsessite.Rollout Sharepoint Solutions - ROSS: ROSS performs the following actions: - Delete sitecollection and restart services - 'Get Latest Version' from SourceSafe - Rebuild Solution - Install all wsp solutions - Create SiteCollections - Check for build en provisioning errors - Send email to developers if errors occurredSchool Management: school managementSQL File Executer: This project is a class library written in c# which is used for executing *.sql files in remote server. Simply one dll file. You include it in your web project, add using statement at the top of your page, pass the parameters inside. Rest, it will do.Startup Manager: Startup Manager launches all startup programs at a managed rate therefore meaning that your computer doesn't crash everytime it starts up and you can use it immediately.stetic: ...Test Infrastructure Guidance: The purpose of this project is to provide guidance to testers in using TFS effectively as an ALM solution. TFS is much more than a simple code repository. Used with Visual Studio it can form a powerful testing solution and remove a lot of pain in dealing with test infrastructure overhead.Tête-à-tête: Tete-a-tete is an address book with a built-in function to send electronic mail over the Internet.Tipeysh! - Add-in that helps you creating C/C++ header files on a single click: Are you also feel miserable when you need to create a new header file in your Visual Studio C/C++ project? Repeatedly choosing "new header file", then writing the annoying (but needed) "#ifndef" section, then writing the class name with it's "private", "protected" and "public" access modifiers... too much clicks and typewriting! Well, there is a solution: Tipeysh! is a simple, easy to use, very handy and configurable Visual Studio Add-In, compatible for both the 2005 and 2008 versions. Once ...UMN Dashboard Project: academic projUsersMOSS: UsersMOSS est une petite application permettant de consulter sur un serveur MOSS les sites web (SPWeb) les users (SPUser), et les groupes (SPGroup). Cette application utilise le modèle objet de MOSS pour inspecter le contenu des objets d'un serveur MOSS. Cette application est loin d'être professionnelle, ou même terminée, mais elle me rend très souvent service. Surtout ne l'utilisez pas sur un serveur de production car le gestion du GC n'est pas faite, ce qui peut provoquer des plantages de v...UtilityLibrary.Win32: UtilityLibrary.Win32UW iLearn: The iLearn activity inference platform is a suite of desktop and mobile tools for logging, modeling, and classifying sensor data for mobile devices. It was created at the University of Washington.VsDocGen: Dynamic javascript documentation generation directly from xml comment documented source code.Windows Live Spaces Photo Album plugin: This is going to be a plugin for Windows Live Writer that will allow you to browse a Windows Live Space Photo Album.Windows Live Writer Plugin for Amazon Books using CueCat: This Windows Live Writer Plugin is for users who use WLW and wish to use their CueCat to scan books. ItemLookups are run against Amazon via its AWS and book image, title, author, and publisher is returned. This project was first created by Scott Hanselman on MSDN's Coding4Fun! X7: X7 makes it easier for win7user to clean the system. You'll no longer have to delete useless stuff in your win7. It's developed in bat.xDT - Commander: Using this application, the user can assign shortcuts (short texts) for various links/URLs. These short texts will be typed into a Textbox to then launch/go to the target (similar to the "Run" program in Windows).

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  • Can you Trust Search?

    - by David Dorf
    An awful lot of referrals to e-commerce sites come from web searches. Retailers rely on search engine optimization (SEO) to correctly position their website so they can be found. Search on "blue jeans" and the results are determined by a semi-secret algorithm -- in my case Levi.com, Banana Republic, and ShopStyle show up. The NY Times recently uncovered a situation where JCPenney, via third-parties hired to help with SEO, was caught manipulating search results so they were erroneously higher in page rankings. No doubt this helped drive additional sales during this part Christmas. The article, The Dirty Little Secrets of Search, is well worth reading. My friend Ron Kleinman started an interesting discussion at the ARTS Linkedin forum. He posed the question: The ability of a single company to "punish" any retailer (by significantly impacting their on-line sales volume) who does not play by their rules ... is this a good thing or a bad thing? Clearly JCP was in the wrong and needed to be punished, but should that decision lie with Google alone? Don't get me wrong -- I'm certainly not advocating we create a Department of Search where bureaucrats think of ways to spend money, but Google wields an awful lot of power in this situation, and it makes me feel uncomfortable. Now Google is incorporating more social aspects into their search results. For example, when Google knows its me (i.e. I'm logged in when using Google) search results will be influenced by my Twitter network. In an effort to increase relevance, the blogs and re-tweeted articles from my network will be higher in the search results than they otherwise would be. So in the case of product searches, things discussed in my network will rise to the top. Continuing my blue jean example, if someone in my network had been discussing Macy's perhaps they would now be higher in the result set. soapbox: I already have lots of spammers posting bogus comments to this blog in an effort to create additional links to their sites and thus increase their search ranking. Should I expect a similar situation in Twitter and eventually Facebook? Now retailers need to expand their SEO efforts to incorporate social media as well, but do us all a favor and please don't cheat.

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  • Architecture strategies for a complex competition scoring system

    - by mikewassmer
    Competition description: There are about 10 teams competing against each other over a 6-week period. Each team's total score (out of a 1000 total available points) is based on the total of its scores in about 25,000 different scoring elements. Most scoring elements are worth a small fraction of a point and there will about 10 X 25,000 = 250,000 total raw input data points. The points for some scoring elements are awarded at frequent regular time intervals during the competition. The points for other scoring elements are awarded at either irregular time intervals or at just one moment in time. There are about 20 different types of scoring elements. Each of the 20 types of scoring elements has a different set of inputs, a different algorithm for calculating the earned score from the raw inputs, and a different number of total available points. The simplest algorithms require one input and one simple calculation. The most complex algorithms consist of hundreds or thousands of raw inputs and a more complicated calculation. Some types of raw inputs are automatically generated. Other types of raw inputs are manually entered. All raw inputs are subject to possible manual retroactive adjustments by competition officials. Primary requirements: The scoring system UI for competitors and other competition followers will show current and historical total team scores, team standings, team scores by scoring element, raw input data (at several levels of aggregation, e.g. daily, weekly, etc.), and other metrics. There will be charts, tables, and other widgets for displaying historical raw data inputs and scores. There will be a quasi-real-time dashboard that will show current scores and raw data inputs. Aggregate scores should be updated/refreshed whenever new raw data inputs arrive or existing raw data inputs are adjusted. There will be a "scorekeeper UI" for manually entering new inputs, manually adjusting existing inputs, and manually adjusting calculated scores. Decisions: Should the scoring calculations be performed on the database layer (T-SQL/SQL Server, in my case) or on the application layer (C#/ASP.NET MVC, in my case)? What are some recommended approaches for calculating updated total team scores whenever new raw inputs arrives? Calculating each of the teams' total scores from scratch every time a new input arrives will probably slow the system to a crawl. I've considered some kind of "diff" approach, but that approach may pose problems for ad-hoc queries and some aggegates. I'm trying draw some sports analogies, but it's tough because most games consist of no more than 20 or 30 scoring elements per game (I'm thinking of a high-scoring baseball game; football and soccer have fewer scoring events per game). Perhaps a financial balance sheet analogy makes more sense because financial "bottom line" calcs may be calculated from 250,000 or more transactions. Should I be making heavy use of caching for this application? Are there any obvious approaches or similar case studies that I may be overlooking?

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  • SQL Server 2008 Compression

    - by Peter Larsson
    Hi! Today I am going to talk about compression in SQL Server 2008. The data warehouse I currently design and develop holds historical data back to 1973. The data warehouse will have an other blog post laster due to it's complexity. However, the server has 60GB of memory (of which 48 is dedicated to SQL Server service), so all data didn't fit in memory and the SAN is not the fastest one around. So I decided to give compression a go, since we use Enterprise Edition anyway. This is the code I use to compress all tables with PAGE compression. DECLARE @SQL VARCHAR(MAX)   DECLARE curTables CURSOR FOR             SELECT 'ALTER TABLE ' + QUOTENAME(OBJECT_SCHEMA_NAME(object_id))                     + '.' + QUOTENAME(OBJECT_NAME(object_id))                     + ' REBUILD PARTITION = ALL WITH (DATA_COMPRESSION = PAGE)'             FROM    sys.tables   OPEN    curTables   FETCH   NEXT FROM    curTables INTO    @SQL   WHILE @@FETCH_STATUS = 0     BEGIN         IF @SQL IS NOT NULL             RAISERROR(@SQL, 10, 1) WITH NOWAIT           FETCH   NEXT         FROM    curTables         INTO    @SQL     END   CLOSE       curTables DEALLOCATE  curTables Copy and paste the result to a new code window and execute the statements. One thing I noticed when doing this, is that the database grows with the same size as the table. If the database cannot grow this size, the operation fails. For me, I first ended up with orphaned connection. Not good. And this is the code I use to create the index compression statements DECLARE @SQL VARCHAR(MAX)   DECLARE curIndexes CURSOR FOR             SELECT      'ALTER INDEX ' + QUOTENAME(name)                         + ' ON '                         + QUOTENAME(OBJECT_SCHEMA_NAME(object_id))                         + '.'                         + QUOTENAME(OBJECT_NAME(object_id))                         + ' REBUILD PARTITION = ALL WITH (FILLFACTOR = 100, DATA_COMPRESSION = PAGE)'             FROM        sys.indexes             WHERE       OBJECTPROPERTY(object_id, 'IsMSShipped') = 0                         AND OBJECTPROPERTY(object_id, 'IsTable') = 1             ORDER BY    CASE type_desc                             WHEN 'CLUSTERED' THEN 1                             ELSE 2                         END   OPEN    curIndexes   FETCH   NEXT FROM    curIndexes INTO    @SQL   WHILE @@FETCH_STATUS = 0     BEGIN         IF @SQL IS NOT NULL             RAISERROR(@SQL, 10, 1) WITH NOWAIT           FETCH   NEXT         FROM    curIndexes         INTO    @SQL     END   CLOSE       curIndexes DEALLOCATE  curIndexes When this was done, I noticed that the 90GB database now only was 17GB. And most important, complete database now could reside in memory! After this I took care of the administrative tasks, backups. Here I copied the code from Management Studio because I didn't want to give too much time for this. The code looks like (notice the compression option). BACKUP DATABASE [Yoda] TO              DISK = N'D:\Fileshare\Backup\Yoda.bak' WITH            NOFORMAT,                 INIT,                 NAME = N'Yoda - Full Database Backup',                 SKIP,                 NOREWIND,                 NOUNLOAD,                 COMPRESSION,                 STATS = 10,                 CHECKSUM GO   DECLARE @BackupSetID INT   SELECT  @BackupSetID = Position FROM    msdb..backupset WHERE   database_name = N'Yoda'         AND backup_set_id =(SELECT MAX(backup_set_id) FROM msdb..backupset WHERE database_name = N'Yoda')   IF @BackupSetID IS NULL     RAISERROR(N'Verify failed. Backup information for database ''Yoda'' not found.', 16, 1)   RESTORE VERIFYONLY FROM    DISK = N'D:\Fileshare\Backup\Yoda.bak' WITH    FILE = @BackupSetID,         NOUNLOAD,         NOREWIND GO After running the backup, the file size was even more reduced due to the zip-like compression algorithm used in SQL Server 2008. The file size? Only 9 GB. //Peso

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  • Infinite detail inside Perlin noise procedural mapping

    - by Dave Jellison
    I am very new to game development but I was able to scour the internet to figure out Perlin noise enough to implement a very simple 2D tile infinite procedural world. Here's the question and it's more conceptual than code-based in answer, I think. I understand the concept of "I plug in (x, y) and get back from Perlin noise p" (I'll call it p). P will always be the same value for the same (x, y) (as long as the Perlin algorithm parameters haven't changed, like altering number of octaves, et cetera). What I want to do is be able to zoom into a square and be able to generate smaller squares inside of the already generated overhead tile of terrain. Let's say I have a jungle tile for overhead terrain but I want to zoom in and maybe see a small river tile that would only be a creek and not large enough to be a full "big tile" of water in the overhead. Of course, I want the same net effect as a Perlin equation inside a Perlin equation if that makes sense? (aka. I want two people playing the game with the same settings to get the same terrain and details every time). I can conceptually wrap my head around the large tile being based on an "zoomed out" coordinate leaving enough room to drill into but this approach doesn't make sense in my head (maybe I'm wrong). I'm guessing with this approach my overhead terrain would lose all of the cohesiveness delivered by the Perlin. Imagine I calculate (0, 0) as overhead tile 1 and then to the east of that I plug in (50, 0). OK, great, I now have 49 pixels of detail I could then "drill down" into. The issue I have in my head with this approach (without attempting it) is that there's no guarantee from my Perlin noise that (0,0) would be a good neighbor to (50,0) as they could have wildly different "elevations" or p/resultant values returning from the Perlin equation when I generate the overhead map. I think I can conceive of using the Perlin noise for the overhead tile to then reuse the p value as a seed for the "detail" level of noise once I zoom in. That would ensure my detail Perlin is always the same configuration for (0,0), (1,0), etc. ad nauseam but I'm not sure if there are better approaches out there or if this is a sound approach at all.

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  • Is commented out code really always bad?

    - by nikie
    Practically every text on code quality I've read agrees that commented out code is a bad thing. The usual example is that someone changed a line of code and left the old line there as a comment, apparently to confuse people who read the code later on. Of course, that's a bad thing. But I often find myself leaving commented out code in another situation: I write a computational-geometry or image processing algorithm. To understand this kind of code, and to find potential bugs in it, it's often very helpful to display intermediate results (e.g. draw a set of points to the screen or save a bitmap file). Looking at these values in the debugger usually means looking at a wall of numbers (coordinates, raw pixel values). Not very helpful. Writing a debugger visualizer every time would be overkill. I don't want to leave the visualization code in the final product (it hurts performance, and usually just confuses the end user), but I don't want to loose it, either. In C++, I can use #ifdef to conditionally compile that code, but I don't see much differnce between this: /* // Debug Visualization: draw set of found interest points for (int i=0; i<count; i++) DrawBox(pts[i].X, pts[i].Y, 5,5); */ and this: #ifdef DEBUG_VISUALIZATION_DRAW_INTEREST_POINTS for (int i=0; i<count; i++) DrawBox(pts[i].X, pts[i].Y, 5,5); #endif So, most of the time, I just leave the visualization code commented out, with a comment saying what is being visualized. When I read the code a year later, I'm usually happy I can just uncomment the visualization code and literally "see what's going on". Should I feel bad about that? Why? Is there a superior solution? Update: S. Lott asks in a comment Are you somehow "over-generalizing" all commented code to include debugging as well as senseless, obsolete code? Why are you making that overly-generalized conclusion? I recently read Robert Glass' "Clean Code", which says: Few practices are as odious as commenting-out code. Don't do this!. I've looked at the paragraph in the book again (p. 68), there's no qualification, no distinction made between different reasons for commenting out code. So I wondered if this rule is over-generalizing (or if I misunderstood the book) or if what I do is bad practice, for some reason I didn't know.

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  • Why lock statements don't scale

    - by Alex.Davies
    We are going to have to stop using lock statements one day. Just like we had to stop using goto statements. The problem is similar, they're pretty easy to follow in small programs, but code with locks isn't composable. That means that small pieces of program that work in isolation can't necessarily be put together and work together. Of course actors scale fine :) Why lock statements don't scale as software gets bigger Deadlocks. You have a program with lots of threads picking up lots of locks. You already know that if two of your threads both try to pick up a lock that the other already has, they will deadlock. Your program will come to a grinding halt, and there will be fire and brimstone. "Easy!" you say, "Just make sure all the threads pick up the locks in the same order." Yes, that works. But you've broken composability. Now, to add a new lock to your code, you have to consider all the other locks already in your code and check that they are taken in the right order. Algorithm buffs will have noticed this approach means it takes quadratic time to write a program. That's bad. Why lock statements don't scale as hardware gets bigger Memory bus contention There's another headache, one that most programmers don't usually need to think about, but is going to bite us in a big way in a few years. Locking needs exclusive use of the entire system's memory bus while taking out the lock. That's not too bad for a single or dual-core system, but already for quad-core systems it's a pretty large overhead. Have a look at this blog about the .NET 4 ThreadPool for some numbers and a weird analogy (see the author's comment). Not too bad yet, but I'm scared my 1000 core machine of the future is going to go slower than my machine today! I don't know the answer to this problem yet. Maybe some kind of per-core work queue system with hierarchical work stealing. Definitely hardware support. But what I do know is that using locks specifically prevents any solution to this. We should be abstracting our code away from the details of locks as soon as possible, so we can swap in whatever solution arrives when it does. NAct uses locks at the moment. But my advice is that you code using actors (which do scale well as software gets bigger). And when there's a better way of implementing actors that'll scale well as hardware gets bigger, only NAct needs to work out how to use it, and your program will go fast on it's own.

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  • How to implement an email unsubscribe system for a site with many kinds of emails?

    - by Mike Liu
    I'm working on a website that features many different types of emails. Users have accounts, and when logged in they have access to a setting page that they can use to customize what types of emails they receive. However, I'd like to also give users an easy way to unsubscribe directly in the emails they receive. I've looked into list unsubscribe headers as well as creating some type of one click link that would unsubscribe a user from that type of email without requiring login or further action. The later would probably require me to break convention and make changes to the database in response to a GET on the link. However, am I incorrect in thinking that either of these would require me to generate and permanently store a unique identifier in my database for every email I ever send, really complicating email delivery? Without that, I'm not sure how I would be able to uniquely identify a user and a type of email in order to change their email preferences, and this identifier would need to be stored forever as a user could have an email sitting in their inbox for a long time before they decide to act on it. Alternatively, I was considering having a no-login page for managing email preferences. In contrast to above where I would need one of these identifiers for each email, this would only need one identifier per user, with no generation or other action required on sending an email. All of these raise security issues, and they could potentially be used by people to tamper with others' email preferences. This could be mitigated somewhat by ensuring that the identifier is really difficult to guess. For the once per user identifier approach, I was considering generating the identifier by passing a user's ID through some type of encryption algorithm, is this a sound approach? For the per-email identifiers, perhaps I could use a user's ID appended to the time. However, even this would not eliminate the problem entirely, as this would really just be security through obscurity, and anyone with the URL could tamper, and in the end the main defense would have to be that most people aren't so bored as to tamper with other people's email preferences. Are there any other alternatives I've missed, or issues or solutions with these that anyone can provide insight on? What are best practices in this area?

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  • Did I lost my RAID again?

    - by BarsMonster
    Hi! A little history: 2 years ago I was really excited to find out that mdadm is so powerful so it even can reshape arrays so you can start with a smaller array and the grow it as you need. I've bought 3x1Tb drives and made RAID-5. It was fine for a year. Then I bought 2x more, and tried to reshape to RAID-6 out of 5 drives, and due to some mess with superblock versions, lost all content. Had to rebuild it from scratch, but 2Tb of data were gone. Yesterday I bought 2 more drives, and this time I had everything: properly built array, UPS. I've disabled write intent map, added 2 new drives as a spare and run a command to grow array to 7-disk. It started working, but speed was ridiculously slow, ~100kb/sec. AFter processing first 37Mb at such an amasing speed, one of old HDDs fails. I properly shutdown PC and disconnected failed drive. After bootup it appeared it recreated intent map as it was still in mdadm config, so I removed it from config and rebooted again. Now all I see is that all mdadm processes deadlocks, and don't do anything. PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1937 root 20 0 12992 608 444 D 0 0.1 0:00.00 mdadm 2283 root 20 0 12992 852 704 D 0 0.1 0:00.01 mdadm 2287 root 20 0 0 0 0 D 0 0.0 0:00.01 md0_reshape 2288 root 18 -2 12992 820 676 D 0 0.1 0:00.01 mdadm And all I see in mdstat is: $ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid6 sdb1[1] sdg1[4] sdf1[7] sde1[6] sdd1[0] sdc1[5] 2929683456 blocks super 1.2 level 6, 1024k chunk, algorithm 2 [7/6] [UU_UUUU] [>....................] reshape = 0.0% (37888/976561152) finish=567604147.2min speed=0K/sec I've already tried mdadm 2.6.7, 3.1.4 and 3.2 - nothing helps. Did I lost my data again? Any suggestions how can I make it work? OS is Ubuntu Server 10.04.2... PS. Needless to say that data is unaccessible - I cannot mount /dev/md0 as save the most valuable data. You can see my disappointment - the very specific thing I was excited about failed twice taking 5Tb of my data with it.

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  • It's called College.

    - by jeffreyabecker
    Today I saw yet another 'GUID vs int as your primary key' article. Like most of the ones I've read this was filled with technical misrepresentations and out-right fallices. Chef's famous line that "There's a time and a place for everything children" applies here. GUIDs have distinct advantages and disadvantages which should be considered when choosing a data type for the primary key. Fallacy 1: "Its easier" An integer data type(tinyint, smallint, int, bigint) is a better artifical key than a GUID because its easier to remember. I'm a firm believer that your artifical primary keys should be opaque gibberish. PK's are an implementation detail which should never be exposed to the user or relied on for business logic. If you want things to come back in an order, add and ORDER BY clause and SortOrder fields. If you want a human-usable look-up add a business key with a unique constraint. If you want to know what order things were inserted into a table add a timestamp. Fallacy 2: "Size Matters" For many applications, the size of the artifical primary key is going to be irrelevant. The particular article which kicked this post off stated repeatedly that joining against an int has better performance than joining against a GUID. In computer science the performance of your algorithm is always a function of the number of data points. This still holds true for databases. Unless your table is very large, the performance difference between an int and a guid probably isnt going to be mesurable let alone noticeable. My personal experience is that the performance becomes an issue when you start having billions of rows in the table. At this point, you should probably start looking to move from int to bigint so the effective space/performance gain isnt as much as you'd think. GUID Advantages: Insert-ability / Mergeability: You can reliably insert guids into tables without key collisions. Database Independence: Saving entities to the database often requires knowing ids. With identity based ids the id must be selected back after every insert. GUIDs can be generated application-side allowing much faster inserts. GUID Disadvantages: Generatability: You can calculate the next id for an integer pk pretty easily in your head but will need a program to generate GUIDs. Solution: "Select top 100 newid() from sysobjects" Fragmentation: most GUID generation algorithms generate pseudo random GUIDs. This can cause inserts into the middle of your clustered index. Solutions: add a default of newsequentialid() or use GuidComb in NHibernate.

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  • How to load stacking chunks on the fly?

    - by Brettetete
    I'm currently working on an infinite world, mostly inspired by minecraft. A Chunk consists of 16x16x16 blocks. A block(cube) is 1x1x1. This runs very smoothly with a ViewRange of 12 Chunks (12x16) on my computer. Fine. When I change the Chunk height to 256 this becomes - obviously - incredible laggy. So what I basically want to do is stacking chunks. That means my world could be [8,16,8] Chunks large. The question is now how to generate chunks on the fly? At the moment I generate not existing chunks circular around my position (near to far). Since I don't stack chunks yet, this is not very complex. As important side note here: I also want to have biomes, with different min/max height. So in Biome Flatlands the highest layer with blocks would be 8 (8x16) - in Biome Mountains the highest layer with blocks would be 14 (14x16). Just as example. What I could do would be loading 1 Chunk above and below me for example. But here the problem would be, that transitions between different bioms could be larger than one chunk on y. My current chunk loading in action For the completeness here my current chunk loading "algorithm" private IEnumerator UpdateChunks(){ for (int i = 1; i < VIEW_RANGE; i += ChunkWidth) { float vr = i; for (float x = transform.position.x - vr; x < transform.position.x + vr; x += ChunkWidth) { for (float z = transform.position.z - vr; z < transform.position.z + vr; z += ChunkWidth) { _pos.Set(x, 0, z); // no y, yet _pos.x = Mathf.Floor(_pos.x/ChunkWidth)*ChunkWidth; _pos.z = Mathf.Floor(_pos.z/ChunkWidth)*ChunkWidth; Chunk chunk = Chunk.FindChunk(_pos); // If Chunk is already created, continue if (chunk != null) continue; // Create a new Chunk.. chunk = (Chunk) Instantiate(ChunkFab, _pos, Quaternion.identity); } } // Skip to next frame yield return 0; } }

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  • Do I have to worry about "error: superfluous RAID member"?

    - by 0xC0000022L
    When running update-grub on the newly installed Ubuntu 12.04 with an older software RAID (md), I get: error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). Generating grub.cfg ... error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). Found linux image: /boot/vmlinuz-3.2.0-24-generic Found initrd image: /boot/initrd.img-3.2.0-24-generic error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). Found linux image: /boot/vmlinuz-3.2.0-23-generic Found initrd image: /boot/initrd.img-3.2.0-23-generic error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). Found memtest86+ image: /boot/memtest86+.bin error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). error: superfluous RAID member (5 found). Found Debian GNU/Linux (5.0.9) on /dev/sdb1 Found Debian GNU/Linux (5.0.9) on /dev/sdc1 done I would be less worried if the message would say warning: ..., but since it says error: ... I'm wondering what the problem is. # cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md2 : active raid1 sdc1[1] sdb1[0] 48829440 blocks [2/2] [UU] md3 : active raid1 sdc2[1] sdb2[0] 263739008 blocks [2/2] [UU] md1 : active raid5 sdg1[3] sdf1[2] sde1[1] sdh1[0] sdi1[4] sdd1[5](S) 1250274304 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU] unused devices: <none> Do I have to worry or is this harmless? btw: disregard the mentioning of Debian 5.0.9, that was the previously installed system and is going to be overwritten. It's on /dev/md2 actually.

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  • What does the `dmesg` error: "composite sync not supported" mean?

    - by M. Tibbits
    Question: I see [ 20.473125] composite sync not supported and several such entries when I run dmesg. What do they mean? Background: I'm trying to debug a problem where my laptop won't suspend. Since acpi seems happy and I can suspend easily from the command line, I've turned to tracking down all boot-up errors/warnings. So I run dmesg | grep not and, amongst other shtuff, I get: 728:[ 17.267120] composite sync not supported 733:[ 18.009061] composite sync not supported 740:[ 18.159289] registered panic notifier 749:[ 18.162500] vga16fb: not registering due to another framebuffer present 757:[ 18.598251] composite sync not supported 776:[ 20.473125] composite sync not supported 777:[ 20.932266] composite sync not supported 778:[ 28.350231] composite sync not supported 779:[ 28.924913] composite sync not supported 780:[ 35.480658] composite sync not supported And the full log for the few lines right around that first appearance (line 728) is listed at the bottom of my post (I'd happily include anything else). Any ideas what could be causing this? I've read several sites: Ubuntuforums #1 IRC Chat #1 One post talks about ??Adobe flash?? causing this error? Some others also suggest that it might be an nvidia related problem, but I've got a Dell Latitude D630 with an integrated Intel graphics -- so nvidia isn't the problem. [ 17.207142] phy0: Selected rate control algorithm 'minstrel' [ 17.207833] Registered led device: b43-phy0::tx [ 17.207849] Registered led device: b43-phy0::rx [ 17.207865] Registered led device: b43-phy0::radio [ 17.207927] Broadcom 43xx driver loaded [ Features: PL, Firmware-ID: FW13 ] [ 17.267120] composite sync not supported [ 17.415795] EXT4-fs (sda2): mounted filesystem with ordered data mode [ 17.602131] [drm] initialized overlay support [ 17.620201] input: DualPoint Stick as /devices/platform/i8042/serio1/input/input7 [ 17.641192] input: AlpsPS/2 ALPS DualPoint TouchPad as /devices/platform/i8042/serio1/input/input8 [ 18.009061] composite sync not supported [ 18.106042] pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3af: clean. [ 18.108115] pcmcia_socket pcmcia_socket0: cs: IO port probe 0x3e0-0x4ff: clean. [ 18.108941] pcmcia_socket pcmcia_socket0: cs: IO port probe 0x820-0x8ff: clean. [ 18.109676] pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcf7: clean. [ 18.110356] pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean. [ 18.159286] fb0: inteldrmfb frame buffer device [ 18.159289] registered panic notifier [ 18.160218] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A03:00/LNXVIDEO:01/input/input9 [ 18.160286] ACPI: Video Device [VID1] (multi-head: yes rom: no post: no) [ 18.160334] ACPI Warning for \_SB_.PCI0.VID2._DOD: Return Package has no elements (empty) (20090903/nspredef-433) [ 18.160432] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A03:00/LNXVIDEO:02/input/input10 [ 18.160491] ACPI: Video Device [VID2] (multi-head: yes rom: no post: no) [ 18.160539] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0 [ 18.162494] vga16fb: initializing [ 18.162497] vga16fb: mapped to 0xc00a0000 [ 18.162500] vga16fb: not registering due to another framebuffer present [ 18.176091] HDA Intel 0000:00:1b.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 [ 18.176123] HDA Intel 0000:00:1b.0: setting latency timer to 64 [ 18.285752] input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:1b.0/input/input11 [ 18.312497] input: HDA Intel Mic at Ext Left Jack as /devices/pci0000:00/0000:00:1b.0/sound/card0/input12 [ 18.312586] input: HDA Intel HP Out at Ext Left Jack as /devices/pci0000:00/0000:00:1b.0/sound/card0/input13 [ 18.328043] usbcore: registered new interface driver ndiswrapper [ 18.460909] Console: switching to colour frame buffer device 180x56 [ 18.598251] composite sync not supported

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  • SQL – Contest to Get The Date – Win USD 50 Amazon Gift Cards and Cool Gift

    - by Pinal Dave
    If you are a regular reader of this blog – you will find no issue at all in resolving this puzzle. This contest is based on my experience with NuoDB. If you are not familiar with NuoDB, here are few pointers for you. Step by Step Guide to Download and Install NuoDB – Getting Started with NuoDB Quick Start with Admin Sections of NuoDB – Manage NuoDB Database Quick Start with Explorer Sections of NuoDB – Query NuoDB Database In today’s contest you have to answer following questions: Q 1: Precision of NOW() What is the precision of the NuoDB’s NOW() function, which returns current date time? Hint: Run following script on NuoDB Console Explorer section: SELECT NOW() AS CurrentTime FROM dual; Here is the image. I have masked the area where the time precision is displayed. Q 2: Executing Date and Time Script When I execute following script - SELECT 'today' AS Today, 'tomorrow' AS Tomorrow, 'yesterday' AS Yesterday FROM dual; I will get the following result:   NOW – What will be the answer when we execute following script? and WHY? SELECT CAST('today' AS DATE) AS Today, CAST('tomorrow' AS DATE) AS Tomorrow, CAST('yesterday'AS DATE) AS Yesterday FROM dual; HINT: Install NuoDB (it takes 90 seconds). Prizes: 2 Amazon Gifts 2 Limited Edition Hoodies (US resident only)   Rules: Please leave an answer in the comments section below. You must answer both the questions together in a single comment. US resident who wants to qualify to win NuoDB apparel please mention your country in the comment. You can resubmit your answer multiple times, the latest entry will be considered valid. Last day to participate in the puzzle is June 24, 2013. All valid answer will be kept hidden till June 24, 2013. The winner will be announced on June 25, 2013. Two Winners will get USD 25 worth Amazon Gift Card. (Total Value = 25 x 2 = 50 USD) The winner will be selected using a random algorithm from all the valid answers. Anybody with a valid email address can take part in the contest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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  • Creating predefinied camera views - How do I move the camera to make sense while using Controller?

    - by Deukalion
    I'm trying to understand 3D but the one thing I can't seem to understand is the Camera. Right now I'm rendering four 3D Cubes with textures and I set the Project Matrix: public BasicCamera3D(float fieldOfView, float aspectRatio, float clipStart, float clipEnd, Vector3 cameraPosition, Vector3 cameraLookAt) { projection_fieldOfView = MathHelper.ToRadians(fieldOfView); projection_aspectRatio = aspectRatio; projection_clipstart = clipStart; projection_clipend = clipEnd; matrix_projection = Matrix.CreatePerspectiveFieldOfView(projection_fieldOfView, aspectRatio, clipStart, clipEnd); view_cameraposition = cameraPosition; view_cameralookat = cameraLookAt; matrix_view = Matrix.CreateLookAt(cameraPosition, cameraLookAt, Vector3.Up); } BasicCamera3D gameCamera = new BasicCamera3D(45f, GraphicsDevice.Viewport.AspectRatio, 1.0f, 1000f, new Vector3(0, 0, 8), new Vector3(0, 0, 0)); This creates a sort of "Top-Down" camera, with 8 (still don't get the unit type here - it's not pixels I guess?) But, if I try to position the camera at the side to make "Side-View" or "Reverse Side View" camera, the camera is rotating to much until it's turned around it a couple of times. I render the boxes at: new Vector3(-1, 0, 0) new Vector3(0, 0, 0) new Vector3(1, 0, 0) new Vector3(1, 0, 1) and with the Top-Down camera it shows good, but I don't get how I can make the camera show the side or 45 degrees from top (Like 3rd person action games) because the logic doesn't make sense. Also, since every object you render needs a new BasicEffect with a new projection/view/world - can you still use the "same" camera always so you don't have to create a new View/Matrix and such for each object. It's seems weird. If someone could help me get the camera to navigate around my objects "naturally" so I can be able to set a few predtermined views to choose from it would be really helpful. Are there some sort of algorithm to calculate the view for this and perhaps not simply one value? Examples: Top-Down-View: I have an object at 0, 0, 0 when I turn the right stick on the Xbox 360 Controller it should rotate around that object kind of, not flip and turn upside down, disappear and then magically appear as a tiny dot somewhere I have no clue where it is like it feels like it does now. Side-View: I have an object at 0, 0, 0 when I rotate to sides or up and down, the camera should be able to show a little more of the periphery to each side (depending on which you look at), and the same while moving up or down.

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  • Are there deprecated practices for multithread and multiprocessor programming that I should no longer use?

    - by DeveloperDon
    In the early days of FORTRAN and BASIC, essentially all programs were written with GOTO statements. The result was spaghetti code and the solution was structured programming. Similarly, pointers can have difficult to control characteristics in our programs. C++ started with plenty of pointers, but use of references are recommended. Libraries like STL can reduce some of our dependency. There are also idioms to create smart pointers that have better characteristics, and some version of C++ permit references and managed code. Programming practices like inheritance and polymorphism use a lot of pointers behind the scenes (just as for, while, do structured programming generates code filled with branch instructions). Languages like Java eliminate pointers and use garbage collection to manage dynamically allocated data instead of depending on programmers to match all their new and delete statements. In my reading, I have seen examples of multi-process and multi-thread programming that don't seem to use semaphores. Do they use the same thing with different names or do they have new ways of structuring protection of resources from concurrent use? For example, a specific example of a system for multithread programming with multicore processors is OpenMP. It represents a critical region as follows, without the use of semaphores, which seem not to be included in the environment. th_id = omp_get_thread_num(); #pragma omp critical { cout << "Hello World from thread " << th_id << '\n'; } This example is an excerpt from: http://en.wikipedia.org/wiki/OpenMP Alternatively, similar protection of threads from each other using semaphores with functions wait() and signal() might look like this: wait(sem); th_id = get_thread_num(); cout << "Hello World from thread " << th_id << '\n'; signal(sem); In this example, things are pretty simple, and just a simple review is enough to show the wait() and signal() calls are matched and even with a lot of concurrency, thread safety is provided. But other algorithms are more complicated and use multiple semaphores (both binary and counting) spread across multiple functions with complex conditions that can be called by many threads. The consequences of creating deadlock or failing to make things thread safe can be hard to manage. Do these systems like OpenMP eliminate the problems with semaphores? Do they move the problem somewhere else? How do I transform my favorite semaphore using algorithm to not use semaphores anymore?

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  • How can I solve this SAT edge case?

    - by ssb
    I have an SAT implementation that basically works, and the fact that it works is what's giving me a few headaches. Basically there are some situations where using the SAT doesn't quite give me my intended result. One of these involves movement across multiple collision objects. Or to put it another way, if I have several collision boxes lined up next to each other such as to create something like a wall or a floor, movement along that surface while constantly applying force into that surface sometimes causes hangups, i.e. the player stops moving. This illustration shows what I mean: The 2 boxes on the bottom represent a floor, and the box on top/in the middle represents what my player is doing. There are several squares lined up as world obstacles to create some kind of wall, and if I move to the left across this surface while holding the down key then the issue arises. It only happens at the exact dividing point between two blocks. It only happens when moving to the left. At any rate I think I know why it happens, but I don't know how to solve it. Basically when I update my player movement I consider which directions are pressed, naturally, so if down is pressed I will add the speed to the Y component, and so on. But due to the way my SAT is implemented, when the penetration into the shape is the same from both sides it just goes with the smallest axis that it finds first, and it checks collisions against objects in the order that they were created because it goes through a foreach loop on the list of collidable objects. So this all adds up to the effect of if I'm moving to the left over a series of boxes while holding down, it will resolve me back to the right out of the first box and then up out of the box to the right of it, and this continues as long as the penetration is the same. The odd part is that this doesn't happen every time, which I am going to attribute to some oddity regarding multiplying velocity by the game time and causing some minor discrepancies between the lengths. Ultimately what this boils down to is that it will keep resolving me to the right and up, but this is technically expected behavior. All the solutions I can think of only address the symptoms of this problem and not the actual cause, such as not using many blocks to create walls or shapes, which is an option I'd like to keep open. I could also change which axis my algorithm defaults to, but that would just cause problems when going up/down along the walls. What can I do to fix this?

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  • How can I convert a 2D bitmap (Used for terrain) to a 2D polygon mesh for collision?

    - by Megadanxzero
    So I'm making an artillery type game, sort of similar to Worms with all the usual stuff like destructible terrain etc... and while I could use per-pixel collision that doesn't give me collision normals or anything like that. Converting it all to a mesh would also mean I could use an existing physics library, which would be better than anything I can make by myself. I've seen people mention doing this by using Marching Squares to get contours in the bitmap, but I can't find anything which mentions how to turn these into a mesh (Unless it refers to a 3D mesh with contour lines defining different heights, which is NOT what I want). At the moment I can get a basic Marching Squares contour which looks something like this (Where the grid-like lines in the background would be the Marching Squares 'cells'): That needs to be interpolated to get a smoother, more accurate result but that's the general idea. I had a couple ideas for how to turn this into a mesh, but many of them wouldn't work in certain cases, and the one which I thought would work perfectly has turned out to be very slow and I've not even finished it yet! Ideally I'd like whatever I end up using to be fast enough to do every frame for cases such as rapidly-firing weapons, or digging tools. I'm thinking there must be some kind of existing algorithm/technique for turning something like this into a mesh, but I can't seem to find anything. I've looked at some things like Delaunay Triangulation, but as far as I can tell that won't correctly handle concave shapes like the above example, and also wouldn't account for holes within the terrain. I'll go through the technique I came up with for comparison and I guess I'll see if anyone has a better idea. First of all interpolate the Marching Squares contour lines, creating vertices from the line ends, and getting vertices where lines cross cell edges (Important). Then, for each cell containing vertices create polygons by using 2 vertices, and a cell corner as the 3rd vertex (Probably the closest corner). Do this for each cell and I think you should have a mesh which accurately represents the original bitmap (Though there will only be polygons at the edges of the bitmap, and large filled in areas in between will be empty). The only problem with this is that it involves lopping through every pixel once for the initial Marching Squares, then looping through every cell (image height + 1 x image width + 1) at least twice, which ends up being really slow for any decently sized image...

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  • Backup Azure Tables with the Enzo Backup API

    - by Herve Roggero
    In case you missed it, you can now backup (and restore) Azure Tables and SQL Databases using an API directly. The features available through the API can be found here: http://www.bluesyntax.net/backup20api.aspx and the online help for the API is here: http://www.bluesyntax.net/EnzoCloudBackup20/APIIntro.aspx. Backing up Azure Tables can’t be any easier than with the Enzo Backup API. Here is a sample code that does the trick: // Create the backup helper class. The constructor automatically sets the SourceStorageAccount property StorageBackupHelper backup = new StorageBackupHelper("storageaccountname", "storageaccountkey", "sourceStorageaccountname", "sourceStorageaccountkey", true, "apilicensekey"); // Now set some properties… backup.UseCloudAgent = false;                                       // backup locally backup.DeviceURI = @"c:\TMP\azuretablebackup.bkp";    // to this file backup.Override = true; backup.Location = DeviceLocation.LocalFile; // Set optional performance options backup.PKTableStrategy.Mode = BSC.Backup.API.TableStrategyMode.GUID; // Set GUID strategy by default backup.MaxRESTPerSec = 200; // Attempt to stay below 200 REST calls per second // Start the backup now… string taskId = backup.Backup(); // Use the Environment class to get the final status of the operation EnvironmentHelper env = new EnvironmentHelper("storageaccountname", "storageaccountkey", "apilicensekey"); string status = env.GetOperationStatus(taskId);   As you can see above, the code is straightforward. You provide connection settings in the constructor, set a few options indicating where the backup device will be located, set optional performance parameters and start the backup. The performance options are designed to help you backup your Azure Tables quickly, while attempting to keep under a specific threshold to prevent Storage Account throttling. For example, the MaxRESTPerSec property will attempt to keep the overall backup operation under 200 rest calls per second. Another performance option if the Backup Strategy for Azure Tables. By default, all tables are simply scanned. While this works best for smaller Azure Tables, larger tables can use the GUID strategy, which will issue requests against an Azure Table in parallel assuming the PartitionKey stores GUID values. It doesn’t mean that your PartitionKey must have GUIDs however for this strategy to work; but the backup algorithm is tuned for this condition. Other options are available as well, such as filtering which columns, entities or tables are being backed up. Check out more on the Blue Syntax website at http://www.bluesyntax.net.

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  • 2D SAT Collision Detection not working when using certain polygons

    - by sFuller
    My SAT algorithm falsely reports that collision is occurring when using certain polygons. I believe this happens when using a polygon that does not contain a right angle. Here is a simple diagram of what is going wrong: Here is the problematic code: std::vector<vec2> axesB = polygonB->GetAxes(); //loop over axes B for(int i = 0; i < axesB.size(); i++) { float minA,minB,maxA,maxB; polygonA->Project(axesB[i],&minA,&maxA); polygonB->Project(axesB[i],&minB,&maxB); float intervalDistance = polygonA->GetIntervalDistance(minA, maxA, minB, maxB); if(intervalDistance >= 0) return false; //Collision not occurring } This function retrieves axes from the polygon: std::vector<vec2> Polygon::GetAxes() { std::vector<vec2> axes; for(int i = 0; i < verts.size(); i++) { vec2 a = verts[i]; vec2 b = verts[(i+1)%verts.size()]; vec2 edge = b-a; axes.push_back(vec2(-edge.y,edge.x).GetNormailzed()); } return axes; } This function returns the normalized vector: vec2 vec2::GetNormailzed() { float mag = sqrt( x*x + y*y ); return *this/mag; } This function projects a polygon onto an axis: void Polygon::Project(vec2* axis, float* min, float* max) { float d = axis->DotProduct(&verts[0]); float _min = d; float _max = d; for(int i = 1; i < verts.size(); i++) { d = axis->DotProduct(&verts[i]); _min = std::min(_min,d); _max = std::max(_max,d); } *min = _min; *max = _max; } This function returns the dot product of the vector with another vector. float vec2::DotProduct(vec2* other) { return (x*other->x + y*other->y); } Could anyone give me a pointer in the right direction to what could be causing this bug?

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  • How can I keep directories in sync

    - by Guillaume Boudreau
    I have a directory, dirA, that users can work in: they can create, modify, rename and delete files & sub-directores in dirA. I want to keep another directory, dirB, in sync with dirA. What I'd like, is a discussion on finding a working algorithm that would achieve the above, with the limitations listed below. Requirements: 1. Something asynchronous - I don't want to stop file operations in dirA while I work in dirB. 2. I can't assume that I can just blindly rsync dirA to dirB on regular interval - dirA could contain millions of files & directories, and terrabytes of data. Completely walking the dirA tree could take hours. Those two requirements makes this really difficult. Having it asynchronous means that when I start working on a specific file from dirA, it might have moved a lot since it appeared. And the second limitation means that I really need to watch dirA, and work on atomic file operations that I notice. Current (broken) implementation: 1. Log all file & directory operations in dirA. 2. Using a separate process, read that log, and 'repeat' all the logged operations in dirB. Why is it broken: echo 1 > dirA/file1 # Allow the 'log reader' process to create dirB/file1: log = "write dirA/file1"; action = cp dirA/file1 dirB/file1; result = OK echo 1 > dirA/file2 mv dirA/file1 dirA/file3 mv dirA/file2 dirA/file1 rm dirA/file3 # End result: file1 contains '1' # 'log reader' process starts working on the 4 above file operations: log = "write file2"; action = cp dirA/file2 dirB/file2; result = failed: there is no dirA/file2 log = "rename file1 file3"; action = mv dirB/file1 dirB/file3; result = OK log = "rename file2 file1"; action = mv dirB/file2 dirB/file1; result = failed: there is no dirB/file2 log = "delete file3"; action = rm dirB/file3; result = OK # End result in dirB: no more files! Another broken example: echo 1 > dirA/dir1/file1 mv dirA/dir1 dirA/dir2 # 'log reader' process starts working on the 2 above file operations: log = "write file1"; action = cp dirA/dir1/file1 dirB/dir1/file1; result = failed: there is no dirA/dir1/file1 log = "rename dir1 dir2"; action = mv dirB/dir1 dirB/dir2; result = failed: there is no dirA/dir1 # End result if dirB: nothing!

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  • Class instance clustering in object reference graph for multi-entries serialization

    - by Juh_
    My question is on the best way to cluster a graph of class instances (i.e. objects, the graph nodes) linked by object references (the -directed- edges of the graph) around specifically marked objects. To explain better my question, let me explain my motivation: I currently use a moderately complex system to serialize the data used in my projects: "marked" objects have a specific attributes which stores a "saving entry": the path to an associated file on disc (but it could be done for any storage type providing the suitable interface) Those object can then be serialized automatically (eg: obj.save()) The serialization of a marked object 'a' contains implicitly all objects 'b' for which 'a' has a reference to, directly s.t: a.b = b, or indirectly s.t.: a.c.b = b for some object 'c' This is very simple and basically define specific storage entries to specific objects. I have then "container" type objects that: can be serialized similarly (in fact their are or can-be "marked") they don't serialize in their storage entries the "marked" objects (with direct reference): if a and a.b are both marked, a.save() calls b.save() and stores a.b = storage_entry(b) So, if I serialize 'a', it will serialize automatically all objects that can be reached from 'a' through the object reference graph, possibly in multiples entries. That is what I want, and is usually provides the functionalities I need. However, it is very ad-hoc and there are some structural limitations to this approach: the multi-entry saving can only works through direct connections in "container" objects, and there are situations with undefined behavior such as if two "marked" objects 'a'and 'b' both have a reference to an unmarked object 'c'. In this case my system will stores 'c' in both 'a' and 'b' making an implicit copy which not only double the storage size, but also change the object reference graph after re-loading. I am thinking of generalizing the process. Apart for the practical questions on implementation (I am coding in python, and use Pickle to serialize my objects), there is a general question on the way to attach (cluster) unmarked objects to marked ones. So, my questions are: What are the important issues that should be considered? Basically why not just use any graph parsing algorithm with the "attach to last marked node" behavior. Is there any work done on this problem, practical or theoretical, that I should be aware of? Note: I added the tag graph-database because I think the answer might come from that fields, even if the question is not.

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  • iwlwifi on lenovo z570 disabled by hardware switch

    - by Kevin Gallagher
    It was working fine with windows 7. The hardware switch is not disabled. I've toggled it back and forth dozens of times. The wifi light never turns on and it always lists as hardware disabled. I have the latest updates installed. I've been searching for solutions, but none of them seem to work for me. I've tried removing acer-wmi. I've tried setting 11n_disable=1. I've tried resetting the bios. I've tried using rfkill to unblock (only removes soft block). I've rebooted dozens of times. The wifi light turns off as soon as grub loads. Edit: I have a usb edimax wireless nic. It shows hardware disabled as well (although rfkill lists as unblocked). If I unload iwlwifi the usb nic works fine. uname -a `Linux xxx-Ideapad-Z570 3.2.0-55-generic #85-Ubuntu SMP Wed Oct 2 12:29:27 UTC 2013 x86_64 x86_64 x86_64 GNU/Linu`x rfkill list 19: phy18: Wireless LAN Soft blocked: no Hard blocked: yes dmesg [43463.022996] Intel(R) Wireless WiFi Link AGN driver for Linux, in-tree: [43463.023002] Copyright(c) 2003-2011 Intel Corporation [43463.023107] iwlwifi 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [43463.023190] iwlwifi 0000:03:00.0: setting latency timer to 64 [43463.023253] iwlwifi 0000:03:00.0: pci_resource_len = 0x00002000 [43463.023257] iwlwifi 0000:03:00.0: pci_resource_base = ffffc900057c8000 [43463.023261] iwlwifi 0000:03:00.0: HW Revision ID = 0x0 [43463.023797] iwlwifi 0000:03:00.0: irq 43 for MSI/MSI-X [43463.024013] iwlwifi 0000:03:00.0: Detected Intel(R) Centrino(R) Wireless-N 1000 BGN, REV=0x6C [43463.024250] iwlwifi 0000:03:00.0: L1 Enabled; Disabling L0S [43463.045496] iwlwifi 0000:03:00.0: device EEPROM VER=0x15d, CALIB=0x6 [43463.045501] iwlwifi 0000:03:00.0: Device SKU: 0X50 [43463.045504] iwlwifi 0000:03:00.0: Valid Tx ant: 0X1, Valid Rx ant: 0X3 [43463.045542] iwlwifi 0000:03:00.0: Tunable channels: 13 802.11bg, 0 802.11a channels [43463.045744] iwlwifi 0000:03:00.0: RF_KILL bit toggled to disable radio. [43463.047652] iwlwifi 0000:03:00.0: loaded firmware version 39.31.5.1 build 35138 [43463.047823] Registered led device: phy18-led [43463.047895] cfg80211: Ignoring regulatory request Set by core since the driver uses its own custom regulatory domain [43463.048037] ieee80211 phy18: Selected rate control algorithm 'iwl-agn-rs' [43463.055533] ADDRCONF(NETDEV_UP): wlan0: link is not ready nm-tool State: connected (global) - Device: wlan0 ---------------------------------------------------------------- Type: 802.11 WiFi Driver: iwlwifi State: unavailable Default: no HW Address: 74:E5:0B:4A:9F:C2 Capabilities: Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points lshw -C network *-network DISABLED description: Wireless interface product: Centrino Wireless-N 1000 [Condor Peak] vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 00 serial: 74:e5:0b:4a:9f:c2 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-55-generic firmware=39.31.5.1 build 35138 latency=0 link=no multicast=yes wireless=IEEE 802.11bg resources: irq:43 memory:f1500000-f1501fff lspci 03:00.0 Network controller: Intel Corporation Centrino Wireless-N 1000 [Condor Peak]

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  • MS in Computer Science after BE in electronics

    - by Abhinav
    I am doing my 3rd year Bachelors in Electronics and Electrical Communication but from the first year I have been interested in Computer Science. But at that time it was just my hobby. But in second year when I joined robotics my love for computer science rose. I with my team came in top three in 2 National Competition (Technical fests of different IITs) where we used Image Processing, Hardware interfacing etc. But then I realised that Computer Science is not just about coding. I took many lectures from online free schools like Udacity, Coursera in subjects related to Artificial Intelligence, Building a Search Engine, Design and Analysis of Algorithm, Programming a Robotic Car, Programming Languages, Machine Learning, Software Engineering as a Service, WebApps Engineering, Compilers, Applied Crypotography etc. I also did some courses in Core and Advanced Java in my second year from training institute. I will also be taking course in Statistics, Databases, Discrete Mathematics from 25th June. Now I realized how vast is the field of Computer Science and how efficient you become on deciding algorithms and classifying problems into different subfields which have been thoroughly researched so you don't always do brute force thing or naive programming. Now this field has become kind of passion for me. Adding to the fact I am also doing my 6 months internship in software field in Texas Instruments where I am working on Automation and Algorithms. I also have some 5-6 good college level projects in Softwares and Robotics. I also like Electronics but only some fields like Operating System(this subject was there in Electronics also), Micro Processor, Digital, Computer Architecture, DSPs etc. I really want to pursue MS in some field of Computer Science. I am giving GRE in October/November. Till now I have good CG of around 9.4/10 and my 1 year in college is still left. Do I have any chance that some good University in US will consider me for MS in field related to computer science or Robotics. Also Can you suggest somethings that I can do during this 1 year to increase my chances for MS or should I apply for EECS(Electrical Engineering and Computer Science) and then I can shift more towards Computer Science as my major option. My main aim is to do Phd after Ms in CS if I am able to do that somehow. I know that I have to put much extra effort to understand things in MS than CS undergraduates but I will do that with my full dedication, also when I communicate with my college CS students or during my internship period I didn't feel that I am missing very much stuff that they know and was very comfortable during my internship with software employees.

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