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• SQL SERVER – An Efficiency Tool to Compare and Synchronize SQL Server Databases

  - by Pinal Dave

  There is no need to reinvent the wheel if it is already invented and if the wheel is already available at ease, there is no need to wait to grab it. Here is the similar situation. I came across a very interesting situation and I had to look for an efficient tool which can make my life easier and solve my business problem. Here is the scenario. One of the developers had deleted few rows from the very important mapping table of our development server (thankfully, it was not the production server). Though it was a development server, the entire development team had to stop working as the application started to crash on every page. Think about the lost of manpower and efficiency which we started to loose.  Pretty much every department had to stop working as our internal development application stopped working. Thankfully, we even take a backup of our development server and we had access to full backup of the entire database at 6 AM morning. We do not take as a frequent backup of development server as production server (naturally!). Even though we had a full backup, the solution was not to restore the database. Think about it, there were plenty of the other operations since the last good full backup and if we restore a full backup, we will pretty much overwrite on the top of the work done by developers since morning. Now, as restoring the full backup was not an option we decided to restore the same database on another server. Once we had restored our database to another server, the challenge was to compare the table from where the database was deleted. The mapping table from where the data were deleted contained over 5000 rows and it was humanly impossible to compare both the tables manually. Finally we decided to use efficiency tool dbForge Data Compare for SQL Server from DevArt. dbForge Data Compare for SQL Server is a powerful, fast and easy to use SQL compare tool, capable of using native SQL Server backups as metadata source. (FYI we Downloaded dbForge Data Compare) Once we discovered the product, we immediately downloaded the product and installed on our development server. After we installed the product, we were greeted with the following screen. We clicked on the New Data Comparision to start our new comparison project. It brought up following screen. Here is the best part of the product, we just had to enter our database connection username and password along with source and destination details and we are done. The entire process is very simple and self intuiting. The best part was that for the source, we can either select database or even backup. This was indeed fantastic feature. Think about this, if you have a very big database, it will take long time to restore on the server. Once it is restored, you will be able to work with it. However, when you are working with dbForge Data Compare it will accept database backup as your source or destination. Once I click on the execute it brought up following screen where it displayed an excellent summary of the data compare. It has dedicated tabs for the what is changing in what table as well had details of the changed data. The best part is that, once we had reviewed the change. We click on the Synchronize button in the menu bar and it brought up following screen. You can see that the screen has very simple straight forward but very powerful features. You can generate a script to synchronize from target to source or even from source to target. Additionally, the database is a very complicated world and there are extensive options to configure various database options on the next screen. We also have the option to either generate script or directly execute the script to target server. I like to play on the safe side and I generated the script for my synchronization and later on after review I deployed the scripts on the server. Well, my team and we were able to get going from our disaster in less than 10 minutes. There were few people in our team were indeed disappointed as they were thinking of going home early that day but in less than 10 minutes they had to get back to work. There are so many other features in  dbForge Data Compare for SQL Server, I am already planning to make this product company wide recommended product for Data Compare tool. Hats off to the team who have build this product. Here are few of the features salient features of the dbForge Data Compare for SQL Server Perform SQL Server database comparison to detect changes Compare SQL Server backups with live databases Analyze data differences between two databases Synchronize two databases that went out of sync Restore data of a particular table from the backup Generate data comparison reports in Excel and HTML formats Copy look-up data from development database to production Automate routine data synchronization tasks with command-line interface Go Ahead and Download the dbForge Data Compare for SQL Server right away. It is always a good idea to get familiar with the important tools before hand instead of learning it under pressure of disaster. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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• Gene Hunt Says:

  - by BizTalk Visionary

  "She's as nervous as a very small nun at a penguin shoot"   "He's got fingers in more pies than a leper on a cookery course" "You so much as belch out of line and I'll have your scrotum on a barbed wire plate" "Let's go play slappyface" "your surrounded by armed barstewards" “Right, get out and find this murdering scum right now!” [pause] “Scratch that, we start 9am sharp tomorrow, it's beer-o-clock.” "So then Cartwright, you're such a good Detective.... Go and Detect me a packet of Garibaldies" "You're not the one who is going to have to knit himself a new arsehole after 25 years of aggressive male love in prison" “A dream for me is Diana Dors and a bottle of chip fat." “A dream for me is Diana Dors and a bottle of chip fat." “They reckon you've got concussion - but personally, I couldn't give a tart's furry cup if half your brains are falling out. Don't ever waltz into my kingdom playing king of the jungle.” “You great... soft... sissy... girlie... nancy... french... bender... Man-United supporting POOF!!” “Drugs eh? What's the point. They make you forget, make you talk funny, make you see things that aren't there. My old grandma got all of that for free when she had a stroke.” “He's Dead! It's quite serious!” “Fanny in the flat...Nice Work” “SoopaDoopa” “Tits in a Jumper!” “Drop your weapons! You are surrounded by armed bastards!” “It's 1973, almost dinnertime. I'm 'avin 'oops!” “Trust the Gene Genie!” “I wanna hump Britt Ekland...What're we gonna do...!” “Was that 'E' and you don't know the rest?! or you going 'Eeee, I Dunno'” “Good Girl! Prostate probe and no jelly. “ “Give over, it's nothing like Spain!” “I'll come over your houses and stamp on all your toys!” “The Wizard will sort it out. It's cos of the wonderful things he does” “Cartwright can jump up and down on his knackers!” “It's not a windup love, he really thinks like this!” “Women! You can't say two words to them” “I was thinking, maybe, a Berni Inn!” “If I wanted a bollocking for drinking too much...!” “Shhhh...hear that...that's the sound of this case being closed! “Chicken!? In a basket!?” “Seems a large quantity of cocaine...” “You probably thought he kept his cock in his keks!” “The tail-end of Rays demotion speech!” “Stephen Warren is gay!?” “You're a smart boy, use your initiative!” “Don't be such a Jessie!” “I find the idea of a bird brushing her teeth...!” “Never been tempted to the Magic talcum powder?” “Make sure she's got nice tits!” “You're more likely to find an ostrich with a plum up it's arse!” “Drink this lot under the table and have a pint on the way home!” “Never be a female Prime Minister!” “Pub? Pub! pub!.....Pub!” “Thou shalt not suck off rent boys!” “The number for the special clinic is on the notice board!” “If me uncle had tits, would he be me auntie!” “Got your vicars in a twist!” “We Done?!” “Your mates got balls...If they were any bigger he'd need a wheelbarrow!” “The Ending - from 'I want to go home' to the end music.”

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• C# 4.0: Covariance And Contravariance In Generics

  - by Paulo Morgado

  C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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• Exitus Acta Probat: The Post-Processing Module

  - by Phil Factor

  Sometimes, one has to make certain ethical compromises to ensure the success of a corporate IT project. Exitus Acta Probat (literally 'the result validates the deeds' meaning that the ends justify the means)It was a while back, whilst working as a Technical Architect for a well-known international company, that I was given the task of designing the architecture of a rather specialized accounting system. We'd tried an off-the-shelf (OTS) Windows-based solution which crashed with dispiriting regularity, and didn't quite do what the business required. After a great deal of research and planning, we commissioned a Unux-based system that used X-terminals for the desktops of  the participating staff. X terminals are now obsolete, but were then hot stuff; stripped-down Unix workstations that provided client GUIs for networked applications long before the days of AJAX, Flash, Air and DHTML. I've never known a project go so smoothly: I'd been initially rather nervous about going the Unix route, believing then that  Unix programmers were excitable creatures who were prone to  indulge in role-play enactments of elves and wizards at the weekend, but the programmers I met from the company that did the work seemed to be rather donnish, earnest, people who quickly grasped our requirements and were faultlessly professional in their work.After thinking lofty thoughts for a while, there was considerable pummeling of keyboards by our suppliers, and a beautiful robust application was delivered to us ahead of dates.Soon, the department who had commissioned the work received shiny new X Terminals to replace their rather depressing lavatory-beige PCs. I modestly hung around as the application was commissioned and deployed to the department in order to receive the plaudits. They didn't come. Something was very wrong with the project. I couldn't put my finger on the problem, and the users weren't doing any more than desperately and futilely searching the application to find a fault with it.Many times in my life, I've come up against a predicament like this: The roll-out of an application goes wrong and you are hearing nothing that helps you to discern the cause but nit-*** noise. There is a limit to the emotional heat you can pack into a complaint about text being in the wrong font, or an input form being slightly cramped, but they tried their best. The answer is, of course, one that every IT executive should have tattooed prominently where they can read it in emergencies: In Vino Veritas (literally, 'in wine the truth', alcohol loosens the tongue. A roman proverb) It was time to slap the wallet and get the department down the pub with the tab in my name. It was an eye-watering investment, but hedged with an over-confident IT director who relished my discomfort. To cut a long story short, The real reason gushed out with the third round. We had deprived them of their PCs, which had been good for very little from the pure business perspective, but had provided them with many hours of happiness playing computer-based minesweeper and solitaire. There is no more agreeable way of passing away the interminable hours of wage-slavery than minesweeper or solitaire, and the employees had applauded the munificence of their employer who had provided them with the means to play it. I had, unthinkingly, deprived them of it.I held an emergency meeting with our suppliers the following day. I came over big with the notion that it was in their interests to provide a solution. They played it cool, probably knowing that it was my head on the block, not theirs. In the end, they came up with a compromise. they would temporarily descend from their lofty, cerebral stamping grounds  in order to write a server-based Minesweeper and Solitaire game for X Terminals, and install it in a concealed place within the system. We'd have to pay for it, though. I groaned. How could we do that? "Could we call it a 'post-processing module?" suggested their account executive.And so it came to pass. The application was a resounding success. Every now and then, the staff were able to indulge in some 'post-processing', with what turned out to be a very fine implementation of both minesweeper and solitaire. There were several refinements: A single click in a 'boss' button turned the games into what looked just like a financial spreadsheet.  They even threw in a multi-user version of Battleships. The extra payment for the post-processing module went through the change-control process without anyone untoward noticing, and peace once more descended. Only one thing niggles. Those games were good. Do they still survive, somewhere in a Linux library? If so, I'd like to claim a small part in their production.

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• FY12 Partner Kickoff – Are you Ready?

  - by user715249

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Want to know what Oracle has up its sleeve for FY12? Join us on June 28th (or 29th depending on your region) as we kick off the new year and fill you in on our latest plans. This live, interactive session will be hosted by Judson Althoff and he’s bringing some top Oracle executives into the studio with him. Take a peek below as Lydia Smyers, Oracle WW A&C vice president, talks about this upcoming event. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} As if that weren’t enough, Oracle President Mark Hurd will update you on his focus for partners in FY12 and OPN will be making a special announcement for our ISV partners highlighting some exciting new offerings on how we will go to market together.  But wait, there’s more – you’ll also hear from Oracle product executives and regional sales leaders outlining their priorities for the upcoming year.  Phew – We’re tired just thinking about all of the great content that will be shared on June 28th/29th.  There are a lot of exciting announcements in store for you later this month so tune in for the latest updates! Register now to get your name on ‘the list’, The OPN Communications Team

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• Do You Develop Your PL/SQL Directly in the Database?

  - by thatjeffsmith

  I know this sounds like a REALLY weird question for many of you. Let me make one thing clear right away though, I am NOT talking about creating and replacing PLSQL objects directly into a production environment. Do we really need to talk about developers in production again? No, what I am talking about is a developer doing their work from start to finish in a development database. These are generally available to a development team for building the next and greatest version of your databases and database applications. And of course you are using a third party source control system, right? Last week I was in Tampa, FL presenting at the monthly Suncoast Oracle User’s Group meeting. Had a wonderful time, great questions and back-and-forth. My favorite heckler was there, @oraclenered, AKA Chet Justice.  I was in the middle of talking about how it’s better to do your PLSQL work in the Procedure Editor when Chet pipes up - Don’t do it that way, that’s wrong Just press play to edit the PLSQL directly in the database Or something along those lines. I didn’t get what the heck he was talking about. I had been showing how the Procedure Editor gives you much better feedback and support when working with PLSQL. After a few back-and-forths I got to what Chet’s main objection was, and again I’m going to paraphrase: You should develop offline in your SQL worksheet. Don’t do anything in the database until it’s done. I didn’t understand. Were developers expected to be able to internalize and mentally model the PL/SQL engine, see where their errors were, etc in these offline scripts? No, please give Chet more credit than that. What is the ideal Oracle Development Environment? If I were back in the ‘real world’ of database development, I would do all of my development outside of the ‘dev’ instance. My development process looks a little something like this: Do I have a program that already does something like this – copy and paste Has some smart person already written something like this – copy and paste Start typing in the white-screen-of-panic and bungle along until I get something that half-works Tweek, debug, test until I have fooled my subconscious into thinking that it’s ‘good’ As you might understand, I don’t want my co-workers to see the evolution of my code. It would seriously freak them out and I probably wouldn’t have a job anymore (don’t remind me that I already worked myself out of development.) So here’s what I like to do: Run a Local Instance of Oracle on my Machine and Develop My Code Privately I take a copy of development – that’s what source control is for afterall – and run it where no one else can see it. I now get to be my own DBA. If I need a trace – no problem. If I want to run an ASH report, no worries. If I need to create a directory or run some DataPump jobs, that’s all on me. Now when I get my code ‘up to snuff,’ then I will check it into source control and compile it into the official development instance. So my teammates suddenly go from seeing no program, to a mostly complete program. Is this right? If not, it doesn’t seem wrong to me. And after talking to Chet in the car on the way to the local cigar bar, it seems that he’s of the same opinion. So what’s so wrong with coding directly into a development instance? I think ‘wrong’ is a bit strong here. But there are a few pitfalls that you might want to look out for. A few come to mind – and I’m sure Chet could add many more as my memory fails me at the moment. But here goes: Development instance isn’t properly backed up – would hate to lose that work Development is wiped once a week and copied over from Prod – don’t laugh Someone clobbers your code You accidentally on purpose clobber someone else’s code The more developers you have in a single fish pond, the greater chance something ‘bad’ will happen This Isn’t One of Those Posts Where I Tell You What You Should Be Doing I realize many shops won’t be open to allowing developers to stage their own local copies of Oracle. But I would at least be aware that many of your developers are probably doing this anyway – with or without your tacit approval. SQL Developer can do local file tracking, but you should be using Source Control too! I will say that I think it’s imperative that you control your source code outside the database, even if your development team is comprised of a single developer. Store your source code in a file, and control that file in something like Subversion. You would be shocked at the number of teams that do not use a source control system. I know I continue to be shocked no matter how many times I meet another team running by the seat-of-their-pants. I’d love to hear how your development process works. And of course I want to know how SQL Developer and the rest of our tools can better support your processes. And one last thing, if you want a fun and interactive presentation experience, be sure to have Chet in the room

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• What Did You Do? is a Bad Question

  - by Ajarn Mark Caldwell

  Brian Moran (blog | Twitter) did a great presentation today for the PASS Professional Development Virtual Chapter on The Art of Questions.  One of the points that Brian made was that there are good questions and bad (or at least not-as-good) questions.  Good questions tend to open-up the conversation and engender positive reactions (perhaps even trust and respect) between the participants; and bad questions tend to close-down a conversation either through the narrow list of possible responses (e.g. strictly Yes/No) or through the negative reactions they can produce.  And this explains why I so frequently had problems troubleshooting real-time problems with users in the past.  I’ll explain that in more detail below, but before we go on, let me recommend that you watch the recording of Brian’s presentation to learn why the question Why is often problematic in the U.S. and yet we so often resort to it. For a short portion (3 years) of my career, I taught basic computer skills and Office applications in an adult vocational school, and this gave me ample opportunity to do live troubleshooting of user challenges with computers.  And like many people who ended up in computer related jobs, I also have had numerous times where I was called upon by less computer-savvy individuals to help them with some challenge they were having, whether it was part of my job or not.  One of the things that I noticed, especially during my time as a teacher, was that when I was helping somebody, typically the first question I would ask them was, “What did you do?”  This seemed to me like a good way to start my detective work trying to figure out what happened, what went wrong, how to fix it, and how to help the person avoid it again in the future.  I always asked it in a polite tone of voice as I was just trying to gather the facts before diving in deeper.  However; 99.999% of the time, I always got the same answer, “Nothing!”  For a long time this frustrated me because (remember I’m in detective mode at that point) I knew it could not possibly be true.  They HAD to have done SOMETHING…just tell me what were the last actions you took before this problem presented itself.  But no, they always stuck with “Nothing”.  At which point, with frustration growing, and not a little bit of disdain for their lack of helpfulness, I would usually ask them to move aside while I took over their machine and got them out of whatever they had gotten themselves into.  After a while I just grew used to the fact that this was the answer I would usually receive, but I always kept asking because for the .001% of the people who would actually tell me, I could then help them understand what went wrong and how to avoid it in the future. Now, after hearing Brian’s talk, I understand what the problem was.  Even though I meant to just be in an information gathering mode, the words I was using, “What did YOU do?” have such a strong negative connotation that people would instinctively go into defense-mode and stop sharing information that might make them look bad.  Many of them probably were not even consciously aware that they had gone on the defensive, but the self-preservation instinct, especially self-preservation of the ego, is so strong that people would end up there without even realizing it. So, if “What did you do” is a bad question, what would have been better?  Well, one suggestion that Brian makes in his talk is something along the lines of, “Can you tell me what led up to this?” or “what was happening on the computer right before this came up?”  It’s subtle, but the point is to take the focus off of the person and their behavior; instead depersonalizing it and talk about events from more of a 3rd-party observer point of view.  With this approach, people will be more likely to talk about what the computer did and what they did in response to it without feeling the interrogation spotlight is on them.  They are also more likely to mention other events that occurred around the same time that may or may not be related, but which could certainly help you troubleshoot a larger problem if it is not just user actions.  And that is the ultimate goal of your asking the questions.  So yes, it does matter how you ask the question; and there are such things as good questions and bad questions.  Excellent topic Brian!  Thanks for getting the thinking gears churning! (Cross-posted to the Professional Development Virtual Chapter blog.)

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• 2d tank movement and turret solution

  - by Phil

  Hi! I'm making a simple top-down tank game on the ipad where the user controls the movement of the tank with the left "joystick" and the rotation of the turret with the right one. I've spent several hours just trying to get it to work decently but now I turn to the pros :) I have two referencial objects, one for the movement and one for the rotation. The referencial objects always stay max two units away from the tank and I use them to tell the tank in what direction to move. I chose this approach to decouple movement and rotational behaviour from the raw input of the joysticks, I believe this will make it simpler to implement whatever behaviour I want for the tank. My problem is 1; the turret rotates the long way to the target. With this I mean that the target can be -5 degrees away in rotation and still it rotates 355 degrees instead of -5 degrees. I can't figure out why. The other problem is with the movement. It just doesn't feel right to have the tank turn while moving. I'd like to have a solution that would work as well for the AI as for the player. A blackbox function for the movement where the player only specifies in what direction it should move and it moves there under the constraints that are imposed on it. I am using the standard joystick class found in the Unity iPhone package. This is the code I'm using for the movement: public class TankFollow : MonoBehaviour { //Check angle difference and turn accordingly public GameObject followPoint; public float speed; public float turningSpeed; void Update() { transform.position = Vector3.Slerp(transform.position, followPoint.transform.position, speed * Time.deltaTime); //Calculate angle var forwardA = transform.forward; var forwardB = (followPoint.transform.position - transform.position); var angleA = Mathf.Atan2(forwardA.x, forwardA.z) * Mathf.Rad2Deg; var angleB = Mathf.Atan2(forwardB.x, forwardB.z) * Mathf.Rad2Deg; var angleDiff = Mathf.DeltaAngle(angleA, angleB); //print(angleDiff.ToString()); if (angleDiff > 5) { //Rotate to transform.Rotate(new Vector3(0, (-turningSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else if (angleDiff < 5) { transform.Rotate(new Vector3(0, (turningSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else { } transform.position = new Vector3(transform.position.x, 0, transform.position.z); } } And this is the code I'm using to rotate the turret: void LookAt() { var forwardA = -transform.right; var forwardB = (toLookAt.transform.position - transform.position); var angleA = Mathf.Atan2(forwardA.x, forwardA.z) * Mathf.Rad2Deg; var angleB = Mathf.Atan2(forwardB.x, forwardB.z) * Mathf.Rad2Deg; var angleDiff = Mathf.DeltaAngle(angleA, angleB); //print(angleDiff.ToString()); if (angleDiff - 180 > 1) { //Rotate to transform.Rotate(new Vector3(0, (turretSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); } else if (angleDiff - 180 < -1) { transform.Rotate(new Vector3(0, (-turretSpeed * Time.deltaTime),0)); //transform.rotation = new Quaternion(transform.rotation.x, transform.rotation.y + adjustment, transform.rotation.z, transform.rotation.w); print((angleDiff - 180).ToString()); } else { } } Since I want the turret reference point to turn in relation to the tank (when you rotate the body, the turret should follow and not stay locked on since it makes it impossible to control when you've got two thumbs to work with), I've made the TurretFollowPoint a child of the Turret object, which in turn is a child of the body. I'm thinking that I'm making it too difficult for myself with the reference points but I'm imagining that it's a good idea. Please be honest about this point. So I'll be grateful for any help I can get! I'm using Unity3d iPhone. Thanks!

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• Red Gate does Byte Night 2012

  - by red(at)work

  On the 5th of October 2012, a team of nine plucky Red Gaters braved the howling wind and the driving rain to sleep outside. No tents or mattresses were allowed – all we took for protection were sleeping bags, groundsheets, plastic sacks and Colin’s enormous fishing umbrella (a godsend in umbrella-y disguise). Why would we do such a thing? For Byte Night, an annual tech sector sleepout in support of Action for Children, who tackle the causes as well as the consequences of youth homelessness. Byte Night encourages technology professionals to do for one night a year what thousands of young people have to do every night – sleep rough.  We signed up for Byte Night in the warm, heady midst of the British summer, thinking it couldn’t possibly be all that bad. Even on the night itself – before the rain began to fall, sat in the comfort and warmth of a company canteen, drinking wine and eating chill and preparing to win the pub quiz – we were excited and optimistic about the night that lay ahead of us. All of that changed as soon as we stepped out into one of the worst rainstorms of the year. Brian, the team’s birthday boy, describes it best: Picture the scene: it’s 3 am on a Friday. I’m lying outside, fully clothed in a sleeping bag, wearing a raincoat, trussed up inside a large plastic pocket, on a ground sheet beneath a giant umbrella, wedged so tightly between two of my colleagues that I can’t move my arms. I’m wide awake, staring up at the grey sky beyond the edge of the umbrella; a limp, flickering white glow hints at a moon somewhere behind the drifting clouds. I haven’t slept since we first moved outside at 11 pm. Outside. Did I mention we were outside? I’m hung over. I need the loo. But there is no way on earth that I’m getting out of this sleeping bag. It’s cold. It’s raining. Not just raining, but chucking it down. It’s been doing this non-stop since 10pm. The rain sounds like a hyperactive drummer on the fishing umbrella, and the noise is loud and relentless. Puddles of water are forming all over the groundsheet, and, despite being ensconced inside the plastic pouch, I am wet. The fishing umbrella is protecting me from the worst of the driving rain, but not all of me is under it, and five hours of rain is no match for it. Everything is wet. My left side has become horribly damp. My trainers, which I placed next to my sleeping bag, are now completely soaked through. Mmm. That’ll be fun in the morning. My head is next to Colin’s head on one side, and a multi-pack of McCoy’s cheddar and onion crisps on the other. Don’t ask about the tub of hummus. That’s somewhere down by my ankles, abandoned to the night. Jess, who is lying next to me, rolls over onto her side. A mini waterfall cascades from her rain-pouch onto my face. Bah. I continue to stare into the heavens, willing the dawn to hurry up. Something lands on my face. It’s a mosquito. Great. Midnight, when this still seemed like fun – when we opened some champagne and my colleagues presented me with a caterpillar birthday cake, when everyone was drunk and jolly and full of stoic resolve – feels like a long time ago. Did I mention that today is my birthday? The remains of the caterpillar cake endure the same fate as the hummus, left out in the rain like a metaphor for sadness. It’s getting colder. I can see my breath. Silence has descended on the group, apart from the rustle of plastic. And the rain, obviously. Someone snores, and I envy whoever it is the sweet escape of sleep. I try to wriggle a bit further down inside my sleeping bag, but it doesn’t want to be wriggled into. Only 3 hours till dawn. 180 minutes. I begin to count them off, one at a time.  All nine of us got to go home in the morning, but thousands of children across the UK don’t have that luxury. If you’d like to sponsor the Red Gate Byte Night team, our JustGiving page can be found here.   Chris, before the outside bit actually happened. More photos from Byte Night Cambridge 2012 can be found here.

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• SQL Server devs–what source control system do you use, if any? (answer and maybe win free stuff)

  - by jamiet

  Recently I noticed a tweet from notable SQL Server author and community dude-at-large Steve Jones in which he asked how many SQL Server developers were putting their SQL Server source code (i.e. DDL) under source control (I’m paraphrasing because I can’t remember the exact tweet and Twitter’s search functionality is useless). The question surprised me slightly as I thought a more pertinent question would be “how many SQL Server developers are not using source control?” because I have been doing just that for many years now and I simply assumed that use of source control is a given in this day and age. Then I started thinking about it. “Perhaps I’m wrong” I pondered, “perhaps the SQL Server folks that do use source control in their day-to-day jobs are in the minority”. So, dear reader, I’m interested to know a little bit more about your use of source control. Are you putting your SQL Server code into a source control system? If so, what source control server software (e.g. TFS, Git, SVN, Mercurial, SourceSafe, Perforce) are you using? What source control client software are you using (e.g. TFS Team Explorer, Tortoise, Red Gate SQL Source Control, Red Gate SQL Connect, Git Bash, etc…)? Why did you make those particular software choices? Any interesting anecdotes to share in regard to your use of source control and SQL Server? To encourage you to contribute I have five pairs of licenses for Red Gate SQL Source Control and Red Gate SQL Connect to give away to what I consider to be the five best replies (“best” is totally subjective of course but this is my blog so my decision is final ), if you want to be considered don’t forget to leave contact details; email address, Twitter handle or similar will do. To start you off and to perhaps get the brain cells whirring, here are my answers to the questions above: Are you putting your SQL Server code into a source control system? As I think I’ve already said…yes. Always. If so, what source control server software (e.g. TFS, Git, SVN, Mercurial, SourceSafe, Perforce) are you using? I move around a lot between many clients so it changes on a fairly regular basis; my current client uses Team Foundation Server (aka TFS) and as part of a separate project is trialing the use of Team Foundation Service. I have used SVN extensively in the past which I am a fan of (I generally prefer it to TFS) and am trying to get my head around Git by using it for ObjectStorageHelper. What source control client software are you using (e.g. TFS Team Explorer, Tortoise, Red Gate SQL Source Control, Red Gate SQL Connect, Git Bash, etc…)? On my current project, Team Explorer. In the past I have used Tortoise to connect to SVN. Why did you make those particular software choices? I generally use whatever the client uses and given that I work with SQL Server I find that the majority of my clients use TFS, I guess simply because they are Microsoft development shops. Any interesting anecdotes to share in regard to your use of source control and SQL Server? Not an anecdote as such but I am going to share some frustrations about TFS. In many ways TFS is a great product because it integrates many separate functions (source control, work item tracking, build agents) into one whole and I’m firmly of the opinion that that is a good thing if for no reason other than being able to associate your check-ins with a work-item. However, like many people there are aspects to TFS source control that annoy me day-in, day-out. Chief among them has to be the fact that it uses a file’s read-only property to determine if a file should be checked-out or not and, if it determines that it should, it will happily do that check-out on your behalf without you even asking it to. I didn’t realise how ridiculous this was until I first used SVN about three years ago – with SVN you make any changes you wish and then use your source control client to determine which files have changed and thus be checked-in; the notion of “check-out” doesn’t even exist. That sounds like a small thing but you don’t realise how liberating it is until you actually start working that way. Hoping to hear some more anecdotes and opinions in the comments. Remember….free software is up for grabs! @jamiet 

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• Supporting users if they're not on your site

  - by Roger Hart

  Have a look at this Read Write Web article, specifically the paragraph in bold and the comments. Have a wry chuckle, or maybe weep for the future of humanity - your call. Then pause, and worry about information architecture. The short story: Read Write Web bumps up the Google rankings for "Facebook login" at the same time as Facebook makes UI changes, and a few hundred users get confused and leave comments on Read Write Web complaining about not being able to log in to their Facebook accounts.* Blindly clicking the first Google result is not a navigation behaviour I'd anticipated for folks visiting big names sites like Facebook. But then, I use Launchy and don't know where any of my files are, depend on Firefox auto-complete, view Facebook through my IM client, and don't need a map to find my backside with both hands. Not all our users behave in the same way, which means not all of our architecture is within our control, and people can get to your content in all sorts of ways. Even if the Read Write Web episode is a prank of some kind (there are, after all, plenty of folks who enjoy orchestrated trolling) it's still a useful reminder. Your users may take paths through and to your content you cannot control, and they are unlikely to deconstruct their assumptions along the way. I guess the meaningful question is: can you still support those users? If they get to you from Google instead of your front door, does what they find still make sense? Does your information architecture still work if your guests come in through the bathroom window? Ok, so here they broke into the house next door - you can't be expected to deal with that. But the rest is well worth thinking about. Other off-site interaction It's rarely going to be as funny as the comments at Read Write Web, but your users are going to do, say, and read things they think of as being about you and your products, in places you don't control. That's good. If you pay attention to it, you get data. Your users get a better experience. There are easy wins, too. Blogs, forums, social media &c. People may look for and find help with your product on blogs and forums, on Twitter, and what have you. They may learn about your brand in the same way. That's fine, it's an interaction you can be part of. It's time-consuming, certainly, but you have the option. You won't get a blogger to incorporate your site navigation just in case your users end up there, but you can be there when they do. Again, Anne Gentle, Gordon McLean and others have covered this in more depth than I could. Direct contact Sales people, customer care, support, they all talk to people. Are they sending links to your content? if so, which bits? Do they know about all of it? Do they have the content they need to support them - messaging that funnels sales, FAQ that are realistically frequent, detailed examples of things people want to do, that kind of thing. Are they sending links because users can't find the good stuff? Are they sending précis of your content, or re-writes, or brand new stuff? If so, does that mean your content isn't up to scratch, or that you've got content missing? Direct sales/care/support interactions are enormously valuable, and can help you know what content your users find useful. You can't have a table of contents or a "See also" in a phonecall, but your content strategy can support more interactions than browsing. *Passing observation about Facebook. For plenty if folks, it is  the internet. Its services are simple versions of what a lot of people use the internet for, and they're aggregated into one stop. Flickr, Vimeo, Wordpress, Twitter, LinkedIn, and all sorts of games, have Facebook doppelgangers that are not only friendlier to entry-level users, they're right there, behind only one layer of authentication. As such, it could own a lot of interaction convention. Heavy users may well not be tech-savvy, and be quite change averse. That doesn't make this episode not dumb, but I'm happy to go easy on 'em.

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• Personal search – the future of search

  - by jamiet

  [Four months ago I wrote a meandering blog post on another blogging site entitled Personal search – the future of search. The points I made therein are becoming more relevant to what I'm reading about and hoping to get involved in in the future so I'm re-posting here to a wider audience to hopefully get some more feedback and guage reaction to it. This has been prompted by the book Pull by David Siegel that is forming my current holiday reading (recommended to me by a commenter on my previous post Interesting things – Twitter annotations and your phone as a web server) and in particular by Siegel's notion of us all in the future having a personal online data vault.] My one-time colleague Paul Dawson recently wrote an article called The Future of Search and in it he proposed some interesting ideas. Some choice quotes: The growth of Chinese search giant Baidu is an indicator that fully localised and tailored content and offerings have great traction with local audiences This trend is already driving an increase in the use of specialist searches … Look at how Farecast is now integrated into Bing for example, or how Flightstats is now integrated into Google. Search does not necessarily have to begin with a keyword, but could start instead with a click or a touch. Take a look at Retrievr. Start drawing a picture in the box and see what happens. This is certainly search without the need for typing in keywords search technology has advanced greatly in recent years. The recent launch of Microsoft Live Labs’ Pivot has given us a taste of what we can expect to see in the future This really got me thinking about where search might go in the future and as my mind wandered I realised that as the amount of data that we collect about ourselves increases so too will the need and the desire to search it. The amount of electronic data that exists about each and every person is increasing and in the near future I fully expect that we are going to be able to store personal data such as: A history of our location (in fact Google Latitude already offers this facility) Recordings of all our phone conversations Health information history (weight, blood pressure etc…) Energy usage Spending history What films we watch, what radio stations we listen to Voting history Of course, most of this stuff is already stored somewhere but crucially we don’t have easy access to it. My utilities supplier knows how much electricity I’m using but if I want to know for myself I have to go and dig through my statements (assuming I have kept them). Similarly my doctor probably has ready access to all of my health records, my bank knows exactly what I have spent my money on, my cable supplier knows what I watch on TV and my mobile phone supplier probably knows exactly where I am and where I’ve been for the past few years. Strange then that none of this electronic information is available to me in a way that I can really make use of it; after all, its MY information. Its MY data. I created it. That is set to change. As technologies mature and customers become more technically cognizant they will demand more access to the data that companies hold about them. The companies themselves will realise the benefit that they derive from giving users what they want and will embrace ways of providing it. As a result the amount of data that we store about ourselves is going to increase exponentially and the desire to search and derive value from that data is going to grow with it; we are about to enter the era of the “personal datastore” and we will want, and need, to search through it in order to make sense of it all. Its interesting then that today when we think of search we think of search engines and yet in these personal datastores we’re referring to data that search engines can’t touch because WE own it and we (hopefully) choose to keep it private. Someone, I know not who, is going to lead in this space by making it easy for us to search our data and retrieve information that we have either forgotten or maybe didn’t even know in the first place. We will learn new things about ourselves and about our habits; we will share these findings with whomever we choose; we will compare what we discover with others; we will collaborate for mutual benefit and, most of all, we will educate ourselves as to how to live our lives better. Search will be the means to that end, it will enable us to make sense of the wealth of information that we will collect day in day out. The future of search is personal, why would we be interested in anything else? @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Advice on learning programming languages and math.

  - by Joris Ooms

  I feel like I'm getting stuck lately when it comes to learning about programming-related things; I thought I'd ask a question here and write it all down in the hope to get some pointers/advice from people. Perhaps writing it down helps me put things in perspective for myself aswell. I study Interactive Multimedia Design. This course is based on two things: graphic design on one hand, and web development on the other hand. I have quite a decent knowledge of web-related languages (the usual HTML/JS/PHP) and I'll be getting a course on ASP.NET next year. In my free time, I have learnt how to work with CodeIgniter, aswell as some diving into Ruby (and Rails) and basic iOS programming. In my first year of college I also did a class on Java (19/20 on the end result). This grade doesn't really mean anything though; I have the basics of OOP down but Java-wise, we learnt next to nothing. Considering the time I have been programming in, for example, PHP.. I can't say I'm bad at it. I'm definitely not good or great at it, but I'm decent. My teachers tell me I have the programming thing down. They just tell me I should keep on learning. So that's what I do, and I try to take in as much as possible; however, sometimes I'm unsure where to start and I have this tendency to always doubt myself. Now, for the 'question'. I want to get into iOS programming. I know iOS programming boils down to programming in Cocoa Touch and Objective-C. I also know Obj-C is a superset of C. I have done a class on C a couple of years ago, but I failed miserably. I got stuck at pointers and never really understood them.. Until like a month ago. I suddenly 'got' it. I have been working through a book on Objective-C for a week or so now, and I understand the basics (I'm at like.. chapter 6 or so). However, I keep running into similar problems as the ones I had when I did the C class: I suck at math. No, really. I come from a Latin-Modern Languages background in high school and I had nearly no math classes back then. I wanted to study Computer Science, but I failed there because of the miserable state of my mathematics knowledge. I can't explain why I'm suddenly talking about math here though, because it isn't directly related to programming.. yet it is. For example, the examples in the book I'm reading now are about programming a fraction-calculator. All good, I can do the programming when I get the formulas down.. but it takes me a full day or more to actually get to that point. I also find it hard to come up with ideas for myself. I made one small iOS app the other day and it's just a button / label kind of thing. When I press the button, it generates a random number. That's really all I could come up with. Can you 'learn' that? It probably comes down to creativity, but evidently, I'm not too great at being creative. Are there any sites or resources out there that provide something like a basic list of things you can program when you're just starting out? Maybe I'm focusing on too many things at once. I want to keep my HTML/CSS at a decent level, while learning PHP and CodeIgniter, while diving into Ruby on Rails and learning Objective-C and the iOS SDK at the same time. I just want to be good at something, I guess. The problem is that I can't seem to be happy with my PHP stuff. I want more, something 'harder'; that's why I decided to pick up the iOS thing. Like I said, I have the basics down of a lot of different languages. I can program something simple in Java, in C, in Objective-C as of this week.. but it ends there. Mostly because I can't come up with ideas for more complex applications, and also because I just doubt myself: 'Oh, that's too complex, I can never do that'. And then it ends there. To conclude my rant, let me basically rephrase my questions into a 'tl;dr' part. A. I want to get into iOS programming and I have basic knowledge of C/Objective-C. However, I struggle to come up with ideas of my own and implement them and I also suck at math which is something that isn't directly related to, yet often needed while programming. What can I do? B. I have an interest in a lot of different programming languages and I can't stop reading/learning. However, I don't feel like I'm good in anything. Should I perhaps focus on just one language for a year or longer, or keep taking it all in at the same time and hope I'll finally get them all down? C. Are there any resources out there that provide basic ideas of things I can program? I'm thinking about 'simple' command-line applications here to help me while studying C/Obj-C away from the whole iPhone SDK. Like I said, the examples in my book are mainly math-based (fraction calculator) and it's kinda hard. :( Thanks a lot for reading my post. I didn't plan it to be this long but oh well. Thanks in advance for any answers.

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• Why lock-free data structures just aren't lock-free enough

  - by Alex.Davies

  Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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• Frameskipping in Android gameloop causing choppy sprites (Open GL ES 2.0)

  - by user22241

  I have written a simple 2d platform game for Android and am wondering how one deals with frame-skipping? Are there any alternatives? Let me explain further. So, my game loop allows for the rendering to be skipped if game updates and rendering do not fit into my fixed time-slice (16.667ms). This allows my game to run at identically perceived speeds on different devices. And this works great, things do run at the same speed. However, when the gameloop skips a render call for even one frame, the sprite glitches. And thinking about it, why wouldn't it? You're seeing a sprite move say, an average of 10 pixels every 1.6 seconds, then suddenly, there is a pause of 3.2ms, and the sprite then appears to jump 20 pixels. When this happens 3 or 4 times in close succession, the result is very ugly and not something I want in my game. Therfore, my question is how does one deal with these 'pauses' and 'jumps' - I've read every article on game loops I can find (see below) and my loops are even based off of code from these articles. The articles specifically mention frame skipping but they don't make any reference to how to deal with visual glitches that result from it. I've attempted various game-loops. My loop must have a mechanism in-place to allow rendering to be skipped to keep game-speed constant across multiple devices (or alternative, if one exists) I've tried interpolation but this doesn't eliminate this specific problem (although it looks like it may mitigate the issue slightly as when it eventually draws the sprite it 'moves it back' between the old and current positions so the 'jump' isn't so big. I've also tried a form of extrapolation which does seem to keep things smooth considerably, but I find it to be next to completely useless because it plays havoc with my collision detection (even when drawing with a 'display only' coordinate - see extrapolation-breaks-collision-detection) I've tried a loop that uses Thread.sleep when drawing / updating completes with time left over, no frame skipping in this one, again fairly smooth, but runs differently on different devices so no good. And I've tried spawning my own, third thread for logic updates, but this, was extremely messy to deal with and the performance really wasn't good. (upon reading tons of forums, most people seem to agree a 2 thread loops ( so UI and GL threads) is safer / easier). Now if I remove frame skipping, then all seems to run nice and smooth, with or without inter/extrapolation. However, this isn't an option because the game then runs at different speeds on different devices as it falls behind from not being able to render fast enough. I'm running logic at 60 Ticks per second and rendering as fast as I can. I've read, as far as I can see every article out there, I've tried the loops from My Secret Garden and Fix your timestep. I've also read: Against the grain deWITTERS Game Loop Plus various other articles on Game-loops. A lot of the others are derived from the above articles or just copied word for word. These are all great, but they don't touch on the issues I'm experiencing. I really have tried everything I can think of over the course of a year to eliminate these glitches to no avail, so any and all help would be appreciated. A couple of examples of my game loops (Code follows): From My Secret Room public void onDrawFrame(GL10 gl) { //Rre-set loop back to 0 to start counting again loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip) { SceneManager.getInstance().getCurrentScene().updateLogic(); nextGameTick += skipTicks; timeCorrection += (1000d / ticksPerSecond) % 1; nextGameTick += timeCorrection; timeCorrection %= 1; loops++; } extrapolation = (float)(System.currentTimeMillis() + skipTicks - nextGameTick) / (float)skipTicks; render(extrapolation); } And from Fix your timestep double t = 0.0; double dt2 = 0.01; double currentTime = System.currentTimeMillis()*0.001; double accumulator = 0.0; double newTime; double frameTime; @Override public void onDrawFrame(GL10 gl) { newTime = System.currentTimeMillis()*0.001; frameTime = newTime - currentTime; if ( frameTime > (dt*5)) //Allow 5 'skips' frameTime = (dt*5); currentTime = newTime; accumulator += frameTime; while ( accumulator >= dt ) { SceneManager.getInstance().getCurrentScene().updateLogic(); previousState = currentState; accumulator -= dt; } interpolation = (float) (accumulator / dt); render(interpolation); }

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• SQLAuthority News – #TechEdIn – TechEd India 2012 Memories and Photos

  - by pinaldave

  TechEd India 2012 was held in Bangalore last March 21 to 23, 2012. Just like every year, this event is bigger, grander and inspiring. Pinal Dave at TechEd India 2012 Family Event Every single year, TechEd is a special affair for my entire family.  Four months before the start of TechEd, I usually start to build the mental image of the event. I start to think  about various things. For the most part, what excites me most is presenting a session and meeting friends. Seriously, I start thinking about presenting my session 4 months earlier than the event!  I work on my presentation day and night. I want to make sure that what I present is accurate and that I have experienced it firsthand. My wife and my daughter also contribute to my efforts. For us, TechEd is a family event, and the two of them feel equally responsible as well. They give up their family time so I can bring out the best content for the Community. Pinal, Shaivi and Nupur at TechEd India 2012 Guinea Pigs (My Experiment Victims) I do not rehearse my session, ever. However, I test my demo almost every single day till the last moment that I have to present it already. I sometimes go over the demo more than 2-3 times a day even though the event is more than a month away. I have two “guinea pigs”: 1) Nupur Dave and 2) Vinod Kumar. When I am at home, I present my demos to my wife Nupur. At times I feel that people often backup their demo, but in my case, I have backup demo presenters. In the office during lunch time, I present the demos to Vinod. I am sure he can walk my demos easily with eyes closed. Pinal and Vinod at TechEd India 2012 My Sessions I’ve been determined to present my sessions in a real and practical manner. I prefer to present the subject that I myself would be eager to attend to and sit through if I were an audience. Just keeping that principle in mind, I have created two sessions this year. SQL Server Misconception and Resolution Pinal and Vinod at TechEd India 2012 We believe all kinds of stuff – that the earth is flat, or that the forbidden fruit is apple, or that the big bang theory explains the origin of the universe, and so many other things. Just like these, we have plenty of misconceptions in SQL Server as well. I have had this dream of co-presenting a session with Vinod Kumar for the past 3 years. I have been asking him every year if we could present a session together, but we never got it to work out, until this year came. Fortunately, we got a chance to stand on the same stage and present a single subject.  I believe that Vinod Kumar and I have an excellent synergy when we are working together. We know each other’s strengths and weakness. We know when the other person will speak and when he will keep quiet. The reason behind this synergy is that we have worked on 2 Video Learning Courses (SQL Server Indexes and SQL Server Questions and Answers) and authored 1 book (SQL Server Questions and Answers) together. Crowd Outside Session Hall This session was inspired from the “Laurel and Hardy” show so we performed a role-playing of those famous characters. We had an excellent time at the stage and, for sure, the audience had a wonderful time, too. We had an extremely large audience for this session and had a great time interacting with them. Speed Up! – Parallel Processes and Unparalleled Performance Pinal Dave at TechEd India 2012 I wanted to approach this session at level 400 and I was very determined to do so. The biggest challenge I had was that this was a total of 60 minutes of session and the audience profile was very generic. I had to present at level 100 as well at 400. I worked hard to tune up these demos. I wanted to make sure that my messages would land perfectly to the minds of the attendees, and when they walk out of the session, they could use the knowledge I shared on their servers. After the session, I felt an extreme satisfaction as I received lots of positive feedback at the event. At one point, so many people rushed towards me that I was a bit scared that the stage might break and someone would get injured. Fortunately, nothing like that happened and I was able to shake hands with everybody. Pinal Dave at TechEd India 2012 Crowd rushing to Pinal at TechEd India 2012 Networking This is one of the primary reasons many of us visit the annual TechEd event. I had a fantastic time meeting SQL Server enthusiasts. Well, it was a terrific time meeting old friends, user group members, MVPs and SQL Enthusiasts. I have taken many photographs with lots of people, but I have received a very few back. If you are reading this blog and have a photo of us at the event, would you please send it to me so I could keep it in my memory lane? SQL Track Speaker: Jacob and Pinal at TechEd India 2012 SQL Community: Pinal, Tejas, Nakul, Jacob, Balmukund, Manas, Sudeepta, Sahal at TechEd India 2012 Star Speakers: Amit and Balmukund at TechEd India 2012 TechED Rockstars: Nakul, Tejas and Pinal at TechEd India 2012 I guess TechEd is a mix of family affair and culture for me! Hamara TechEd (Our TechEd) Please tell me which photo you like the most! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, SQLServer, T SQL, Technology Tagged: TechEd, TechEdIn

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• Is Linear Tape File System (LTFS) Best For Transportable Storage?

  - by rickramsey

  Those of us in tape storage engineering take a lot of pride in what we do, but understand that tape is the right answer to a storage problem only some of the time. And, unfortunately for a storage medium with such a long history, it has built up a few preconceived notions that are no longer valid. When I hear customers debate whether to implement tape vs. disk, one of the common strikes against tape is its perceived lack of usability. If you could go back a few generations of corporate acquisitions, you would discover that StorageTek engineers recognized this problem and started developing a solution where a tape drive could look just like a memory stick to a user. The goal was to not have to care about where files were on the cartridge, but to simply see the list of files that were on the tape, and click on them to open them up. Eventually, our friends in tape over at IBM built upon our work at StorageTek and Sun Microsystems and released the Linear Tape File System (LTFS) feature for the current LTO5 generation of tape drives as an open specification. LTFS is really a wonderful feature and we’re proud to have taken part in its beginnings and, as you’ll soon read, its future. Today we offer LTFS-Open Edition, which is free for you to use in your in Oracle Enterprise Linux 5.5 environment - not only on your LTO5 drives, but also on your Oracle StorageTek T10000C drives. You can download it free from Oracle and try it out. LTFS does exactly what its forefathers imagined. Now you can see immediately which files are on a cartridge. LTFS does this by splitting a cartridge into two partitions. The first holds all of the necessary metadata to create a directory structure for you to easily view the contents of the cartridge. The second partition holds all of the files themselves. When tape media is loaded onto a drive, a complete file system image is presented to the user. Adding files to a cartridge can be as simple as a drag-and-drop just as you do today on your laptop when transferring files from your hard drive to a thumb drive or with standard POSIX file operations. You may be thinking all of this sounds nice, but asking, “when will I actually use it?” As I mentioned at the beginning, tape is not the right solution all of the time. However, if you ever need to physically move data between locations, tape storage with LTFS should be your most cost-effective and reliable answer. I will give you a few use cases examples of when LTFS can be utilized. Media and Entertainment (M&E), Oil and Gas (O&G), and other industries have a strong need for their storage to be transportable. For example, an O&G company hunting for new oil deposits in remote locations takes very large underground seismic images which need to be shipped back to a central data center. M&E operations conduct similar activities when shooting video for productions. M&E companies also often transfers files to third-parties for editing and other activities. These companies have three highly flawed options for transporting data: electronic transfer, disk storage transport, or tape storage transport. The first option, electronic transfer, is impractical because of the expense of the bandwidth required to transfer multi-terabyte files reliably and efficiently. If there’s one place that has bandwidth, it’s your local post office so many companies revert to physically shipping storage media. Typically, M&E companies rely on transporting disk storage between sites even though it, too, is expensive. Tape storage should be the preferred format because as IDC points out, “Tape is more suitable for physical transportation of large amounts of data as it is less vulnerable to mechanical damage during transportation compared with disk" (See note 1, below). However, tape storage has not been used in the past because of the restrictions created by proprietary formats. A tape may only be readable if both the sender and receiver have the same proprietary application used to write the file. In addition, the workflows may be slowed by the need to read the entire tape cartridge during recall. LTFS solves both of these problems, clearing the way for tape to become the standard platform for transferring large files. LTFS is open and, as long as you’ve downloaded the free reader from our website or that of anyone in the LTO consortium, you can read the data. So if a movie studio ships a scene to a third-party partner to add, for example, sounds effects or a music score, it doesn’t have to care what technology the third-party has. If it’s written back to an LTFS-formatted tape cartridge, it can be read. Some tape vendors like to claim LTFS is a “standard,” but beauty is in the eye of the beholder. It’s a specification at this point, not a standard. That said, we’re already seeing application vendors create functionality to write in an LTFS format based on the specification. And it’s my belief that both customers and the tape storage industry will see the most benefit if we all follow the same path. As such, we have volunteered to lead the way in making LTFS a standard first with the Storage Network Industry Association (SNIA), and eventually through to standard bodies such as American National Standards Institute (ANSI). Expect to hear good news soon about our efforts. So, if storage transportability is one of your requirements, I recommend giving LTFS a look. It makes tape much more user-friendly and it’s free, which allows tape to maintain all of its cost advantages over disk! Note 1 - IDC Report. April, 2011. “IDC’s Archival Storage Solutions Taxonomy, 2011” - Brian Zents Website Newsletter Facebook Twitter

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• Tuning Red Gate: #4 of Some

  - by Grant Fritchey

  First time connecting to these servers directly (keys to the kingdom, bwa-ha-ha-ha. oh, excuse me), so I'm going to take a look at the server properties, just to see if there are any issues there. Max memory is set, cool, first possible silly mistake clear. In fact, these look to be nicely set up. Oh, I'd like to see the ANSI Standards set by default, but it's not a big deal. The default location for database data is the F:\ drive, where I saw all the activity last time. Cool, the people maintaining the servers in our company listen, parallelism threshold is set to 35 and optimize for ad hoc is enabled. No shocks, no surprises. The basic setup is appropriate. On to the problem database. Nothing wrong in the properties. The database is in SIMPLE recovery, but I think it's a reporting system, so no worries there. Again, I'd prefer to see the ANSI settings for connections, but that's the worst thing I can see. Time to look at the queries, tables, indexes and statistics because all the information I've collected over the last several days suggests that we're not looking at a systemic problem (except possibly not enough memory), but at the traditional tuning issues. I just want to note that, I started looking at the system, not the queries. So should you when tuning your environment. I know, from the data collected through SQL Monitor, what my top poor performing queries are, and the most frequently called, etc. I'm starting with the most frequently called. I'm going to get the execution plan for this thing out of the cache (although, with the cache dumping constantly, I might not get it). And it's not there. Called 1.3 million times over the last 3 days, but it's not in cache. Wow. OK. I'll see what's in cache for this database: SELECT  deqs.creation_time,         deqs.execution_count,         deqs.max_logical_reads,         deqs.max_elapsed_time,         deqs.total_logical_reads,         deqs.total_elapsed_time,         deqp.query_plan,         SUBSTRING(dest.text, (deqs.statement_start_offset / 2) + 1,                   (deqs.statement_end_offset - deqs.statement_start_offset) / 2                   + 1) AS QueryStatement FROM    sys.dm_exec_query_stats AS deqs         CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest         CROSS APPLY sys.dm_exec_query_plan(deqs.plan_handle) AS deqp WHERE   dest.dbid = DB_ID('Warehouse') AND deqs.statement_end_offset > 0 AND deqs.statement_start_offset > 0 ORDER BY deqs.max_logical_reads DESC ; And looking at the most expensive operation, we have our first bad boy: Multiple table scans against very large sets of data and a sort operation. a sort operation? It's an insert. Oh, I see, the table is a heap, so it's doing an insert, then sorting the data and then inserting into the primary key. First question, why isn't this a clustered index? Let's look at some more of the queries. The next one is deceiving. Here's the query plan: You're thinking to yourself, what's the big deal? Well, what if I told you that this thing had 8036318 reads? I know, you're looking at skinny little pipes. Know why? Table variable. Estimated number of rows = 1. Actual number of rows. well, I'm betting several more than one considering it's read 8 MILLION pages off the disk in a single execution. We have a serious and real tuning candidate. Oh, and I missed this, it's loading the table variable from a user defined function. Let me check, let me check. YES! A multi-statement table valued user defined function. And another tuning opportunity. This one's a beauty, seriously. Did I also mention that they're doing a hash against all the columns in the physical table. I'm sure that won't lead to scans of a 500,000 row table, no, not at all. OK. I lied. Of course it is. At least it's on the top part of the Loop which means the scan is only executed once. I just did a cursory check on the next several poor performers. all calling the UDF. I think I found a big tuning opportunity. At this point, I'm typing up internal emails for the company. Someone just had their baby called ugly. In addition to a series of suggested changes that we need to implement, I'm also apologizing for being such an unkind monster as to question whether that third eye & those flippers belong on such an otherwise lovely child.

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• The Unspoken - The Why of GC Ergonomics

  - by jonthecollector

  Do you use GC ergonomics, -XX:+UseAdaptiveSizePolicy, with the UseParallelGC collector? The jist of GC ergonomics for that collector is that it tries to grow or shrink the heap to meet a specified goal. The goals that you can choose are maximum pause time and/or throughput. Don't get too excited there. I'm speaking about UseParallelGC (the throughput collector) so there are definite limits to what pause goals can be achieved. When you say out loud "I don't care about pause times, give me the best throughput I can get" and then say to yourself "Well, maybe 10 seconds really is too long", then think about a pause time goal. By default there is no pause time goal and the throughput goal is high (98% of the time doing application work and 2% of the time doing GC work). You can get more details on this in my very first blog. GC ergonomics The UseG1GC has its own version of GC ergonomics, but I'll be talking only about the UseParallelGC version. If you use this option and wanted to know what it (GC ergonomics) was thinking, try -XX:AdaptiveSizePolicyOutputInterval=1 This will print out information every i-th GC (above i is 1) about what the GC ergonomics to trying to do. For example, UseAdaptiveSizePolicy actions to meet *** throughput goal *** GC overhead (%) Young generation: 16.10 (attempted to grow) Tenured generation: 4.67 (attempted to grow) Tenuring threshold: (attempted to decrease to balance GC costs) = 1 GC ergonomics tries to meet (in order) Pause time goal Throughput goal Minimum footprint The first line says that it's trying to meet the throughput goal. UseAdaptiveSizePolicy actions to meet *** throughput goal *** This run has the default pause time goal (i.e., no pause time goal) so it is trying to reach a 98% throughput. The lines Young generation: 16.10 (attempted to grow) Tenured generation: 4.67 (attempted to grow) say that we're currently spending about 16% of the time doing young GC's and about 5% of the time doing full GC's. These percentages are a decaying, weighted average (earlier contributions to the average are given less weight). The source code is available as part of the OpenJDK so you can take a look at it if you want the exact definition. GC ergonomics is trying to increase the throughput by growing the heap (so says the "attempted to grow"). The last line Tenuring threshold: (attempted to decrease to balance GC costs) = 1 says that the ergonomics is trying to balance the GC times between young GC's and full GC's by decreasing the tenuring threshold. During a young collection the younger objects are copied to the survivor spaces while the older objects are copied to the tenured generation. Younger and older are defined by the tenuring threshold. If the tenuring threshold hold is 4, an object that has survived fewer than 4 young collections (and has remained in the young generation by being copied to the part of the young generation called a survivor space) it is younger and copied again to a survivor space. If it has survived 4 or more young collections, it is older and gets copied to the tenured generation. A lower tenuring threshold moves objects more eagerly to the tenured generation and, conversely a higher tenuring threshold keeps copying objects between survivor spaces longer. The tenuring threshold varies dynamically with the UseParallelGC collector. That is different than our other collectors which have a static tenuring threshold. GC ergonomics tries to balance the amount of work done by the young GC's and the full GC's by varying the tenuring threshold. Want more work done in the young GC's? Keep objects longer in the survivor spaces by increasing the tenuring threshold. This is an example of the output when GC ergonomics is trying to achieve a pause time goal UseAdaptiveSizePolicy actions to meet *** pause time goal *** GC overhead (%) Young generation: 20.74 (no change) Tenured generation: 31.70 (attempted to shrink) The pause goal was set at 50 millisecs and the last GC was 0.415: [Full GC (Ergonomics) [PSYoungGen: 2048K-0K(26624K)] [ParOldGen: 26095K-9711K(28992K)] 28143K-9711K(55616K), [Metaspace: 1719K-1719K(2473K/6528K)], 0.0758940 secs] [Times: user=0.28 sys=0.00, real=0.08 secs] The full collection took about 76 millisecs so GC ergonomics wants to shrink the tenured generation to reduce that pause time. The previous young GC was 0.346: [GC (Allocation Failure) [PSYoungGen: 26624K-2048K(26624K)] 40547K-22223K(56768K), 0.0136501 secs] [Times: user=0.06 sys=0.00, real=0.02 secs] so the pause time there was about 14 millisecs so no changes are needed. If trying to meet a pause time goal, the generations are typically shrunk. With a pause time goal in play, watch the GC overhead numbers and you will usually see the cost of setting a pause time goal (i.e., throughput goes down). If the pause goal is too low, you won't achieve your pause time goal and you will spend all your time doing GC. GC ergonomics is meant to be simple because it is meant to be used by anyone. It was not meant to be mysterious and so this output was added. If you don't like what GC ergonomics is doing, you can turn it off with -XX:-UseAdaptiveSizePolicy, but be pre-warned that you have to manage the size of the generations explicitly. If UseAdaptiveSizePolicy is turned off, the heap does not grow. The size of the heap (and the generations) at the start of execution is always the size of the heap. I don't like that and tried to fix it once (with some help from an OpenJDK contributor) but it unfortunately never made it out the door. I still have hope though. Just a side note. With the default throughput goal of 98% the heap often grows to it's maximum value and stays there. Definitely reduce the throughput goal if footprint is important. Start with -XX:GCTimeRatio=4 for a more modest throughput goal (%20 of the time spent in GC). A higher value means a smaller amount of time in GC (as the throughput goal).

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• SQL SERVER – Columnstore Index and sys.dm_db_index_usage_stats

  - by pinaldave

  As you know I have been writing on Columnstore Index for quite a while. Recently my friend Vinod Kumar wrote about  SQL Server 2012: ColumnStore Characteristics. A fantastic read on the subject if you have yet not caught up on that subject. After the blog post I called him and asked what should I write next on this subject. He suggested that I should write on DMV script which I have prepared related to Columnstore when I was writing our SQL Server Questions and Answers book. When we were writing this book SQL Server 2012 CTP versions were available. I had written few scripts related to SQL Server columnstore Index. I like Vinod’s idea and I decided to write about DMV, which we did not cover in the book as SQL Server 2012 was not released yet. We did not want to talk about the product which was not yet released. The first script which I had written was with DMV - sys.column_store_index_stats. This DMV was displaying the statistics of the columnstore indexes. When I attempted to run it on SQL Server 2012 RTM it gave me error suggesting that this DMV does not exists. Here is the script which I ran: SELECT * FROM sys.column_store_index_stats; It generated following error: Msg 208, Level 16, State 1, Line 1 Invalid object name ‘column_store_index_stats’. I was pretty confident that this DMV was available when I had written the scripts. The next reaction was to type ‘sys.’ only in SSMS and wait for intelisense to popup DMV list. I scrolled down and noticed that above said DMV did not exists there as well. Now this is not bug or missing feature. This was indeed something can happen because the version which I was practicing was early CTP version. If you go to the page of the DMV here, it clearly stats notice on the top of the page. This documentation is for preview only, and is subject to change in later releases. Now this was not alarming but my next thought was if this DMV is not there where can I find the information which this DMV was providing. Well, while I was thinking about this, I noticed that my another friend Balmukund Lakhani was online on personal messenger. Well, Balmukund is “Know All” kid. I have yet to find situation where I have not got my answers from him. I immediately pinged him and asked the question regarding where can I find information of ‘column_store_index_stats’. His answer was very abrupt but enlightening for sure. Here is our conversation: Pinal: Where can I find information of column_store_index_stats? Balmukund: Assume you have never worked with CTP before and now try to find the information which you are trying to find. Honestly  it was fantastic response from him. I was confused as I have played extensively with CTP versions of SQL Server 2012. Now his response give me big hint. I should have not looked for DMV but rather should have focused on what I wanted to do. I wanted to retrieve the statistics related to the index. In SQL Server 2008/R2, I was able to retrieve the statistics of the index from the DMV - sys.dm_db_index_usage_stats. I used the same DMV on SQL Server 2012 and it did retrieved the necessary information for me. Here is the updated script which gave me all the necessary information I was looking for. Matter of the fact, if I have used my earlier SQL Server 2008 R2 script this would have just worked fine. SELECT DB_NAME(Database_ID) DBName, SCHEMA_NAME(schema_id) AS SchemaName, OBJECT_NAME(ius.OBJECT_ID) ObjName, i.type_desc, i.name, user_seeks, user_scans, user_lookups, user_updates,* FROM sys.dm_db_index_usage_stats ius INNER JOIN sys.indexes i ON i.index_id = ius.index_id AND ius.OBJECT_ID = i.OBJECT_ID INNER JOIN sys.tables t ON t.OBJECT_ID = i.OBJECT_ID GO Let us see the resultset of above query. You will notice that column Type_desc describes the type of the index. You can additionally write WHERE condition on the column and only retrieve only selected type of Index. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• How do I prove or disprove "god" objects are wrong?

  - by honestduane

  Problem Summary: Long story short, I inherited a code base and an development team I am not allowed to replace and the use of God Objects is a big issue. Going forward, I want to have us re-factor things but I am getting push-back from the teams who want to do everything with God Objects "because its easier" and this means I would not be allowed to re-factor. I pushed back citing my years of dev experience, that I'm the new boss who was hired to know these things, etc, and so did the third party offshore companies account sales rep, and this is now at the executive level and my meeting is tomorrow and I want to go in with a lot of technical ammo to advocate best practices because I feel it will be cheaper in the long run (And I personally feel that is what the third party is worried about) for the company. My issue is from a technical level, I know its good long term but I'm having trouble with the ultra short term and 6 months term, and while its something I "know" I cant prove it with references and cited resources outside of one person (Robert C. Martin, aka Uncle Bob), as that is what I am being asked to do as I have been told having data from one person and only one person (Robert C Martin) is not good enough of an argument. Question: What are some resources I can cite directly (Title, year published, page number, quote) by well known experts in the field that explicitly say this use of "God" Objects/Classes/Systems is bad (or good, since we are looking for the most technically valid solution)? Research I have already done: I have a number of books here and I have searched their indexes for the use of the words "god object" and "god class". I found that oddly its almost never used and the copy of the GoF book I have for example, never uses it (At least according to the index in front of me) but I have found it in 2 books per the below, but I want more I can use. I checked the Wikipedia page for "God Object" and its currently a stub with little reference links so although I personally agree with that it says, It doesn't have much I can use in an environment where personal experience is not considered valid. The book cited is also considered too old to be valid by the people I am debating these technical points with as the argument they are making is that "it was once thought to be bad but nobody could prove it, and now modern software says "god" objects are good to use". I personally believe that this statement is incorrect, but I want to prove the truth, whatever it is. In Robert C Martin's "Agile Principles, Patterns, and Practices in C#" (ISBN: 0-13-185725-8, hardcover) where on page 266 it states "Everybody knows that god classes are a bad idea. We don't want to concentrate all the intelligence of a system into a single object or a single function. One of the goals of OOD is the partitioning and distribution of behavior into many classes and many function." -- And then goes on to say sometimes its better to use God Classes anyway sometimes (Citing micro-controllers as an example). In Robert C Martin's "Clean Code: A Handbook of Agile Software Craftsmanship" page 136 (And only this page) talks about the "God class" and calls it out as a prime example of a violation of the "classes should be small" rule he uses to promote the Single Responsibility Principle" starting on on page 138. The problem I have is all my references and citations come from the same person (Robert C. Martin), and am from the same single person/source. I am being told that because he is just one guy, my desire to not use "God Classes" is invalid and not accepted as a standard best practice in the software industry. Is this true? Am I doing things wrong from a technical perspective by trying to keep to the teaching of Uncle Bob? God Objects and Object Oriented Programming and Design: The more I think of this the more I think this is more something you learn when you study OOP and its never explicitly called out; Its implicit to good design is my thinking (Feel free to correct me, please, as I want to learn), The problem is I "know" this, but but not everybody does, so in this case its not considered a valid argument because I am effectively calling it out as universal truth when in fact most people are statistically ignorant of it since statistically most people are not programmers. Conclusion: I am at a loss on what to search for to get the best additional results to cite, since they are making a technical claim and I want to know the truth and be able to prove it with citations like a real engineer/scientist, even if I am biased against god objects due to my personal experience with code that used them. Any assistance or citations would be deeply appreciated.

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• In the Groove: PASS Board Year 1, Q3

  - by Denise McInerney

  It's nine months into my first year on the PASS Board and I feel like I've found my rhythm. I've accomplished one of the goals I set out for the year and have made progress on others. Here's a recap of the last few months. Anti-Harassment Policy & Process Completed In April I began work on a Code of Conduct for the PASS Summit. The Board had several good discussions and various PASS members provided feedback. You can read more about that in this blog post. Since the document was focused on issues of harassment we renamed it the "Anti-Harassment Policy " and it was approved by the Board in August. The next step was to refine the guideliness and process for enforcement of the AHP. A subcommittee worked on this and presented an update to the Board at the September meeting. You can read more about that in this post, and you can find the process document here. Global Growth Expanding PASS' reach and making the organization relevant to SQL Server communities around the world has been a focus of the Board's work in 2012. We took the Global Growth initiative out to the community for feedback, and everyone on the Board participated, via Twitter chats, Town Hall meetings, feedback forums and in-person discussions. This community participation helped shape and refine our plans. Implementing the vision for Global Growth goes across all portfolios. The Virtual Chapters are well-positioned to help the organization move forward in this area. One outcome of the Global Growth discussions with the community is the expansion of two of the VCs from country-specific to language-specific. Thanks to the leadership in Brazil & Mexico for taking the lead here. I look forward to continued success for the Portuguese- and Spanish-language Virtual Chapters. Together with the Global Chinese VC PASS is off to a good start in making the VC's truly global. Virtual Chapters The VCs continue to grow and expand. Volunteers recently rebooted the Azure and Virutalization VCs, and a new  Education VC will be launching soon. Every week VCs offer excellent free training on a variety of topics. It's the dedication of the VC leaders and volunteers that make all this possible and I thank them for it. Board meeting The Board had an in-person meeting in September in San Diego, CA.. As usual we covered a number of topics including governance changes to support Global Growth, the upcoming Summit, 2013 events and the (then) upcoming PASS election. Next Up Much of the last couple of months has been focused on preparing for the PASS Summit in Seattle Nov. 6-9. I'll be there all week;  feel free to stop me if you have a question or concern, or just to introduce yourself.  Here are some of the places you can find me: VC Leaders Meeting Tuesday 8:00 am the VC leaders will have a meeting. We'll review some of the year's highlights and talk about plans for the next year Welcome Reception The VCs will be at the Welcome Reception in the new VC Lounge. Come by, learn more about what the VCs have to offer and meet others who share your interests. Exceptional DBA Awards Party I'm looking forward to seeing PASS Women in Tech VC leader Meredith Ryan receive her award at this event sponsored by Red Gate Session Presentation I will be presenting a spotlight session entitled "Stop Bad Data in Its OLTP Tracks" on Wednesday at 3:00 p.m. Exhibitor Reception This reception Wednesday evening in the Expo Hall is a great opportunity to learn more about tools and solutions that can help you in your job. Women in Tech Luncheon This year marks the 10th WIT Luncheon at PASS. I'm honored to be on the panel with Stefanie Higgins, Kevin Kline, Kendra Little and Jen Stirrup. This event is on Thursday at 11:30. Community Appreciation Party Thursday evening don't miss this event thanking all of you for everthing you do for PASS and the community. This year we will be at the Experience Music Project and it promises to be a fun party. Board Q & A Friday  9:45-11:15  am the members of the Board will be available to answer your questions. If you have a question for us, or want to hear what other members are thinking about, come by room 401 Friday morning.

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• The standards that fail us and the intellectual bubble

  - by Jeff

  There has been a great deal of noise in the techie community about standards, and a sudden and unexplainable hate for Flash. This noise isn't coming from consumers... the countless soccer moms, teens and your weird uncle Bob, it's coming from the people who build (or at least claim to build) the stuff those consumers consume. If you could survey the position of consumers on the topic, they'd likely tell you that they just want stuff on the Web to work.The noise goes something like this: Web standards are the correct and right thing to use across the Intertubes, and anything not a part of those standards (Flash) is bad. Furthermore, the more recent noise is centered around the idea that HTML 5, along with Javascript, is the right thing to use. The arguments against Flash are, well, the truth is I haven't seen a good argument. I see anecdotal nonsense about high CPU usage and things I'd never think to check when I'm watching Piano Cat on YouTube, but these aren't arguments to me. Sure, I've seen it crash a browser a few times, but it's totally rare.But let's go back to standards. Yes, standards have played an important role in establishing the ubiquity of the Web. The protocols themselves, TCP/IP and HTTP, have been critical. HTML, which has served us well for a very long time, established an incredible foundation. Javascript did an OK job, and thanks to clever programmers writing great frameworks like JQuery, is becoming more and more useful. CSS is awful (there, I said it, I feel SO much better), and I'll never understand why it's so disconnected and different from anything else. It doesn't help that it's so widely misinterpreted by different browsers. Still, there's no question that standards are a good thing, and they've been good for the Web, consumers and publishers alike.HTML 4 has been with us for more than a decade. In Web years, that might as well be 80. HTML 5, contrary to popular belief, is not a standard, and likely won't be for many years to come. In fact, the Web hasn't really evolved at all in terms of its standards. The tools that generate the standard markup and script have, but at the end of the day, we're still living with standards that are more than ten years old. The "official" standards process has failed us.The Web evolved anyway, and did not wait for standards bodies to decide what to do next. It evolved in part because Macromedia, then Adobe, kept evolving Flash. In the earlier days, it mostly just did obnoxious splash pages, but then it started doing animation, and then rich apps as they added form input. Eventually it found its killer app: video. Now more than 95% of browsers have Flash installed. Consumers are better for it.But I'll do it one better... I'll go out on a limb and say that Flash is a standard. If it's that pervasive, I don't care what you tell me, it's a standard. Just because a company owns it doesn't mean that it's evil or not a standard. And hey, it pains me to say that as a developer, because I think the dev tools are the suck (more on that in a minute). But again, consumers don't care. They don't even pay for Flash. The bottom line is that if I put something Flash based on the Internet, it's likely that my audience will see it.And what about the speed of standards owned by a company? Look no further than Silverlight. Silverlight 2 (which I consider the "real" start to the story) came out about a year and a half ago. Now version 4 is out, and it has come a very long way in its capabilities. If you believe Riastats.com, more than half of browsers have it now. It didn't have to wait for standards bodies and nerds drafting documents, it's out today. At this rate, Silverlight will be on version 6 or 7 by the time HTML 5 is a ratified standard.Back to the noise, one of the things that has continually disappointed me about this profession is the number of people who get stuck in an intellectual bubble, color it with dogmatic principles, and completely ignore the actual marketplace where this stuff all has to live. We aren't machines; Binary thinking that forces us to choose between "open standards" and "proprietary lock-in" (the most loaded b.s. FUD term evar) isn't smart at all. The truth is that the <object> tag has allowed us to build incredible stuff on top of the old standards, and consumers have benefitted greatly. Consumer desire, capitalism, and yes, standards ratified by nerds who think about this stuff for years have all played a role in the broad adoption of the Interwebs.We could all do without the noise. At the end of the day, I'm going to build stuff for the Web that's good for my users, and I'm not going to base my decisions on a techie bubble religion. Imagine what the brilliant minds behind the noise could do for the Web if they joined me in that pursuit.

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• Is it Hard to Write a Blog?

  - by Joe Mayo

  Responding to a tweet I received, asking if I found it hard to write a blog and keep it interesting. This is one of the situations where a 140 character response doesn’t do a question justice. There’s a lot to think about between the subjects of writing, subject matter, and entertainment.  Here’s my take on each of these three topics: There’s all types of writing you can do with various degrees of difficulty. If you’re writing a book and you have a gazillion editors bleeding over your every utterance, then the task becomes harder because you’re second-guessing yourself, not knowing whose opinion will be violated. However, if you’re communicating in a public forum, not too many people care about the grammar as much as whether what you have to say is correct.  For a blog, I would say it’s somewhere in-between.  Right now, I’m using Windows Live Writer, which gives me a few advantages to just typing into the blog editor, such as spelling correction and the ability to save my work and resume later.  Overall, writing is one of those things that you just need to get used to.  It’s an essential skill for developers because you need to document your work, depending on what your definition of proper documentation is, and communicate with other developers via various communications mediums. Not begin good (or not thinking that you’re good) shouldn’t hold you back.  Like most things in life, practice will improve your skill.  So, push away that inner voice that keeps you from moving forward and just do it. A good grasp on the subject matter you’re writing about helps.  However, don’t let a lack of knowledge stop you from writing about something. I recall reading something a while back by a developer who didn’t know a technology but wrote about their experience in learning it. They ended up learning more by expressing their thoughts in writing. If you look around out many blogs today, there are many items written by developers learning what they’re writing about.  So, whether you are sure or unsure, you can still write – just be honest with yourself and your readers about what you’re writing. Also, don’t be afraid to have a different opinion or worry if someone will disagree.  I’ll freely admit that it took a while for me to become accustomed to being criticized. Take the good with the bad and use the bad to make yourself better. Guaranteed, someone will disagree with one or more parts of what I’ve written here or think they have a better approach. No problem, more power to them, and whatever constructive comments they have will be a benefit to me in the future; Otherwise, to h*ll with them. :)  Every time you get knocked down, get right back up, dust the dirt off your backside, and keep moving forward.  You’ll learn in time how to align a subject with your own presentation of the material. Entertainment could be hard or could be natural, depending on the personality of yourself and your target audience. It’s even more challenging because you can say something you think is funny and someone will be offended. In fact, there are a lot of things that you shouldn’t say in the name of a joke, but I won’t mention any of them here for want of not offending anyone. Of course, I probably offended someone by saying that and there is probably an organization somewhere in the world out to get me now. I’m probably not the best person to be giving you advice on entertaining an audience.  I mean, every time I try to tell a joke on Twitter 10 people unfriend me. Okay, maybe 15, but you get my point. One thing you might be interested in knowing is that it’s not too hard for one technical person to entertain other technical people, especially when the subject is of interest.  It’s the excitement in each sentence and passion in each paragraph that will keep another developer entertained and interested in what you have to say. Not everyone will like what you’ve written, but the important part is to find your own voice and it’s likely that there is one person in some corner of the world that likes what you have to say, even if it’s your mom and she doesn’t understand a single word you write. :)   If I could leave you with one final thought; Just do it and don’t let anyone or anything hold you back.   Joe

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• Explaining Explain Plan Notes for Auto DOP

  - by jean-pierre.dijcks

  I've recently gotten some questions around "why do I not see a parallel plan" while Auto DOP is on (I think)...? It is probably worthwhile to quickly go over some of the ways to find out what Auto DOP was thinking. In general, there is no need to go tracing sessions and look under the hood. The thing to start with is to do an explain plan on your statement and to look at the parameter settings on the system. Parameter Settings to Look At First and foremost, make sure that parallel_degree_policy = AUTO. If you have that parameter set to LIMITED you will not have queuing and we will only do the auto magic if your objects are set to default parallel (so no degree specified). Next you want to look at the value of parallel_degree_limit. It is typically set to CPU, which in default settings equates to the Default DOP of the system. If you are testing Auto DOP itself and the impact it has on performance you may want to leave it at this CPU setting. If you are running concurrent statements you may want to give this some more thoughts. See here for more information. In general, do stick with either CPU or with a specific number. For now avoid the IO setting as I've seen some mixed results with that... In 11.2.0.2 you should also check that IO Calibrate has been run. Best to simply do a: SQL> select * from V$IO_CALIBRATION_STATUS; STATUS        CALIBRATION_TIME ------------- ---------------------------------------------------------------- READY         04-JAN-11 10.04.13.104 AM You should see that your IO Calibrate is READY and therefore Auto DOP is ready. In any case, if you did not run the IO Calibrate step you will get the following note in the explain plan: Note -----    - automatic DOP: skipped because of IO calibrate statistics are missing One more note on calibrate_io, if you do not have asynchronous IO enabled you will see:  ERROR at line 1: ORA-56708: Could not find any datafiles with asynchronous i/o capability ORA-06512: at "SYS.DBMS_RMIN", line 463 ORA-06512: at "SYS.DBMS_RESOURCE_MANAGER", line 1296 ORA-06512: at line 7 While this is changed in some fixes to the calibrate procedure, you should really consider switching asynchronous IO on for your data warehouse. Explain Plan Explanation To see the notes that are shown and explained here (and the above little snippet ) you can use a simple explain plan mechanism. There should  be no need to add +parallel etc. explain plan for <statement> SELECT PLAN_TABLE_OUTPUT FROM TABLE(DBMS_XPLAN.DISPLAY()); Auto DOP The note structure displaying why Auto DOP did not work (with the exception noted above on IO Calibrate) is like this: Automatic degree of parallelism is disabled: <reason> These are the reason codes: Parameter -  parallel_degree_policy = manual which will not allow Auto DOP to kick in  Hint - One of the following hints are used NOPARALLEL, PARALLEL(1), PARALLEL(MANUAL) Outline - A SQL outline of an older version (before 11.2) is used SQL property restriction - The statement type does not allow for parallel processing Rule-based mode - Instead of the Cost Based Optimizer the system is using the RBO Recursive SQL statement - The statement type does not allow for parallel processing pq disabled/pdml disabled/pddl disabled - For some reason (alter session?) parallelism is disabled Limited mode but no parallel objects referenced - your parallel_degree_policy = LIMITED and no objects in the statement are decorated with the default PARALLEL degree. In most cases all objects have a specific degree in which case Auto DOP will honor that degree. Parallel Degree Limited When Auto DOP does it works you may see the cap you imposed with parallel_degree_limit showing up in the note section of the explain plan: Note -----    - automatic DOP: Computed Degree of Parallelism is 16 because of degree limit This is an obvious indication that your are being capped for this statement. There is one quite interesting one that happens when you are being capped at DOP = 1. First of you get a serial plan and the note changes slightly in that it does not indicate it is being capped (we hope to update the note at some point in time to be more specific). It right now looks like this: Note -----    - automatic DOP: Computed Degree of Parallelism is 1 Dynamic Sampling With 11.2.0.2 you will start seeing another interesting change in parallel plans, and since we are talking about the note section here, I figured we throw this in for good measure. If we deem the parallel (!) statement complex enough, we will enact dynamic sampling on your query. This happens as long as you did not change the default for dynamic sampling on the system. The note looks like this: Note ----- - dynamic sampling used for this statement (level=5)

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