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• Tough Decisions

  - by Johnm

  There was once a thriving business that employed two Database Administrators, Sam and Jim. Both DBAs were certified, educated and highly talented in their skill sets. During lunch breaks these two DBAs were often found together discussing best practices, troubleshooting techniques and the latest release notes for the upcoming version of SQL Server. They genuinely loved what they did. The maintenance of the first database was the responsibility of Sam. He was the architect of this server's setup and he was very meticulous in its configuration. He regularly monitored the health of the database, validated backup files and regularly adhered to the best practices that were advocated by well respected professionals. He was very proud of the fact that there was never a database that he managed that lost data or performed poorly. The maintenance of the second database was the responsibility of Jim. He too was the architect of this server's setup. At the time that he built this server, his understanding of the finer details of configuration were not as clear as they are today. The server was build on a shoestring budget and with very little time for testing and implementation. Jim often monitored the health of the database; but in more of a reactionary mode due to user complaints of slowness or failed transactions. Deadlocks abounded and the backup files were never validated. One day, the announcement was made that revealed that the business had hit financially hard times. Budgets were being cut, limitation on spending was implemented and the reduction in full-time staff was required. Since having two DBAs was regarded a luxury by many, this meant that either Sam or Jim were about to find themselves out of a job. Sam and Jim's boss, Frank, was faced with a very tough decision. Sam's performance was flawless. His techniques and practices were perfection. The databases he managed were reliable and efficient. His solutions are "by the book". When given a task it is certain that, while it may take a little longer, it will be done right the first time. Jim's techniques and practices were not perfect; but effective and responsive. He made mistakes regularly; but he shows that he learns from them and they often result in innovative solutions. When given a task it is certain that, while the results may require some tweaking, it will be done on time and under budget. You are Frank's best friend. He approaches you and presents this scenario. He must layoff one of his valued DBAs the very next morning. Frank asks you: "All else being equal, who would you let go? and Why?" Another pertinent question is raised: "Regardless of good times or bad, if you had to choose, which DBA would you want on your team when tough challenges arise?" Your response is. (This is where you enter a comment below)

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• More SQL Smells

  - by Nick Harrison

  Let's continue exploring some of the SQL Smells from Phil's list. He has been putting together. Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) This is a great example poking holes in the whole theory of "If it works it's not broken" Queries will this probably will generally work and give the correct response. In fact, without careful analysis, you probably may be completely oblivious that there is even a problem. This subtle little problem will needlessly complicate queries and slow them down regardless of the indexes applied. Consider this example: CREATE TABLE [dbo].[Page](     [PageId] [int] IDENTITY(1,1) NOT NULL,     [Title] [varchar](75) NOT NULL,     [Sequence] [int] NOT NULL,     [ThemeId] [int] NOT NULL,     [CustomCss] [text] NOT NULL,     [CustomScript] [text] NOT NULL,     [PageGroupId] [int] NOT NULL;  CREATE PROCEDURE PageSelectBySequence ( @sequenceMin smallint , @sequenceMax smallint ) AS BEGIN SELECT [PageId] , [Title] , [Sequence] , [ThemeId] , [CustomCss] , [CustomScript] , [PageGroupId] FROM [CMS].[dbo].[Page] WHERE Sequence BETWEEN @sequenceMin AND @SequenceMax END  Note that the Sequence column is defined as int while the sequence parameter is defined as a small int. The problem is that the database may have to do a lot of type conversions to evaluate the query. In some cases, this may even negate the indexes that you have in place. Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) There are two main problems here. The first is a little subjective, since this is a non-standard way of expressing the query, it is harder to understand. The other problem is much more objective and potentially problematic. You are taking much of the control away from the optimizer. Written properly, such a query may well out perform a corresponding query written with traditional joins. More likely than not, performance will degrade. Whenever you assume that you know better than the optimizer, you will most likely be wrong. This is the fundmental problem with any hint. Consider a query like this:  SELECT Page.Title , Page.Sequence , Page.ThemeId , Page.CustomCss , Page.CustomScript , PageEffectParams.Name , PageEffectParams.Value , ( SELECT EffectName FROM dbo.Effect WHERE EffectId = dbo.PageEffects.EffectId ) AS EffectName FROM Page INNER JOIN PageEffect ON Page.PageId = PageEffects.PageId INNER JOIN PageEffectParam ON PageEffects.PageEffectId = PageEffectParams.PageEffectId  This can and should be written as:  SELECT Page.Title , Page.Sequence , Page.ThemeId , Page.CustomCss , Page.CustomScript , PageEffectParams.Name , PageEffectParams.Value , EffectName FROM Page INNER JOIN PageEffect ON Page.PageId = PageEffects.PageId INNER JOIN PageEffectParam ON PageEffects.PageEffectId = PageEffectParams.PageEffectId INNER JOIN dbo.Effect ON dbo.Effects.EffectId = dbo.PageEffects.EffectId  The correlated query may just as easily show up in the where clause. It's not a good idea in the select clause or the where clause. Few or No comments. This one is a bit more complicated and controversial. All comments are not created equal. Some comments are helpful and need to be included. Other comments are not necessary and may indicate a problem. I tend to follow the rule of thumb that comments that explain why are good. Comments that explain how are bad. Many people may be shocked to hear the idea of a bad comment, but hear me out. If a comment is needed to explain what is going on or how it works, the logic is too complex and needs to be simplified. Comments that explain why are good. Comments may explain why the sql is needed are good. Comments that explain where the sql is used are good. Comments that explain how tables are related should not be needed if the sql is well written. If they are needed, you need to consider reworking the sql or simplify your data model. Use of functions in a WHERE clause. (Anil Das) Calling a function in the where clause will often negate the indexing strategy. The function will be called for every record considered. This will often a force a full table scan on the tables affected. Calling a function will not guarantee that there is a full table scan, but there is a good chance that it will. If you find that you often need to write queries using a particular function, you may need to add a column to the table that has the function already applied.

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• .NET vs Windows 8

  - by Simon Cooper

  So, day 1 of DevWeek. Lots and lots of Windows 8 and WinRT, as you would expect. The keynote had some actual content in it, fleshed out some of the details of how your apps linked into the Metro infrastructure, and confirmed that there would indeed be an enterprise version of the app store available for Metro apps.) However, that's, not what I want to focus this post on. What I do want to focus on is this: Windows 8 does not make .NET developers obsolete. Phew! .NET in the New Ecosystem In all the hype around Windows 8 the past few months, a lot of developers have got the impression that .NET has been sidelined in Windows 8; C++ and COM is back in vogue, and HTML5 + JavaScript is the New Way of writing applications. You know .NET? It's yesterday's tech. Enter the 21st Century and write <div>! However, after speaking to people at the conference, and after a couple of talks by Dave Wheeler on the innards of WinRT and how .NET interacts with it, my views on the coming operating system have changed somewhat. To summarize what I've picked up, in no particular order (none of this is official, just my sense of what's been said by various people): Metro apps do not replace desktop apps. That is, Windows 8 fully supports .NET desktop applications written for every other previous version of Windows, and will continue to do so in the forseeable future. There are some apps that simply do not fit into Metro. They do not fit into the touch-based paradigm, and never will. Traditional desktop support is not going away anytime soon. The reason Silverlight has been hidden in all the Metro hype is that Metro is essentially based on Silverlight design principles. Silverlight developers will have a much easier time writing Metro apps than desktop developers, as they would already be used to all the principles of sandboxing and separation introduced with Silverlight. It's desktop developers who are going to have to adapt how they work. .NET + XAML is equal to HTML5 + JS in importance. Although the underlying WinRT system is built on C++ & COM, most application development will be done either using .NET or HTML5. Both systems have their own wrapper around the underlying WinRT infrastructure, hiding the implementation details. The CLR is unchanged; it's still the .NET 4 CLR, running IL in .NET assemblies. The thing that changes between desktop and Metro is the class libraries, which have more in common with the Silverlight libraries than the desktop libraries. In Metro, although all the types look and behave the same to callers, some of the core BCL types are now wrappers around their WinRT equivalents. These wrappers are then enhanced using standard .NET types and code to produce the Metro .NET class libraries. You can't simply port a desktop app into Metro. The underlying file IO, network, timing and database access is either completely different or simply missing. Similarly, although the UI is programmed using XAML, the behaviour of the Metro XAML is different to WPF or Silverlight XAML. Furthermore, the new design principles and touch-based interface for Metro applications demand a completely new UI. You will be able to re-use sections of your app encapsulating pure program logic, but everything else will need to be written from scratch. Microsoft has taken the opportunity to remove a whole raft of types and methods from the Metro framework that are obsolete (non-generic collections) or break the sandbox (synchronous APIs); if you use these, you will have to rewrite to use the alternatives, if they exist at all, to move your apps to Metro. If you want to write public WinRT components in .NET, there are some quite strict rules you have to adhere to. But the compilers know about these rules; you can write them in C# or VB, and the compilers will tell you when you do something that isn't allowed and deal with the translation to WinRT metadata rather than .NET assemblies. It is possible to write a class library that can be used in Metro and desktop applications. However, you need to be very careful not to use types that are available in one but not the other. One can imagine developers writing their own abstraction around file IO and UIs (MVVM anyone?) that can be implemented differently in Metro and desktop, but look the same within your shared library. So, if you're a .NET developer, you have a lot less to worry about. .NET is a viable platform on Metro, and traditional desktop apps are not going away. You don't have to learn HTML5 and JavaScript if you don't want to. Hurray!

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• Using Lambdas for return values in Rhino.Mocks

  - by PSteele

  In a recent StackOverflow question, someone showed some sample code they’d like to be able to use.  The particular syntax they used isn’t supported by Rhino.Mocks, but it was an interesting idea that I thought could be easily implemented with an extension method. Background When stubbing a method return value, Rhino.Mocks supports the following syntax: dependency.Stub(s => s.GetSomething()).Return(new Order()); The method signature is generic and therefore you get compile-time type checking that the object you’re returning matches the return value defined by the “GetSomething” method. You could also have Rhino.Mocks execute arbitrary code using the “Do” method: dependency.Stub(s => s.GetSomething()).Do((Func<Order>) (() => new Order())); This requires the cast though.  It works, but isn’t as clean as the original poster wanted.  They showed a simple example of something they’d like to see: dependency.Stub(s => s.GetSomething()).Return(() => new Order()); Very clean, simple and no casting required.  While Rhino.Mocks doesn’t support this syntax, it’s easy to add it via an extension method. The Rhino.Mocks “Stub” method returns an IMethodOptions<T>.  We just need to accept a Func<T> and use that as the return value.  At first, this would seem straightforward: public static IMethodOptions<T> Return<T>(this IMethodOptions<T> opts, Func<T> factory) { opts.Return(factory()); return opts; } And this would work and would provide the syntax the user was looking for.  But the problem with this is that you loose the late-bound semantics of a lambda.  The Func<T> is executed immediately and stored as the return value.  At the point you’re setting up your mocks and stubs (the “Arrange” part of “Arrange, Act, Assert”), you may not want the lambda executing – you probably want it delayed until the method is actually executed and Rhino.Mocks plugs in your return value. So let’s make a few small tweaks: public static IMethodOptions<T> Return<T>(this IMethodOptions<T> opts, Func<T> factory) { opts.Return(default(T)); // required for Rhino.Mocks on non-void methods opts.WhenCalled(mi => mi.ReturnValue = factory()); return opts; } As you can see, we still need to set up some kind of return value or Rhino.Mocks will complain as soon as it intercepts a call to our stubbed method.  We use the “WhenCalled” method to set the return value equal to the execution of our lambda.  This gives us the delayed execution we’re looking for and a nice syntax for lambda-based return values in Rhino.Mocks. Technorati Tags: .NET,Rhino.Mocks,Mocking,Extension Methods

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• PASS Summit 2010 Recap

  - by AjarnMark

  Last week I attended my eighth PASS Summit in nine years, and every year it is a fantastic event!  I was fortunate my first year to have a contact (Bill Graziano (blog | Twitter) from SQLTeam) that I was expecting to meet, and who got me started on a good track of making new contacts.  Each year I have made a few more, and renewed friendships from years past.  Many of the attendees agree that the pure networking opportunities are one of the best benefits of attending the Summit.  And there’s a lot of great technical stuff, too, some of the things that stick out for me this year include… Pre-Con Monday: PowerShell with Allen White (blog | Twitter).  This was the first time that I attended a pre-con.  For those not familiar with the concept, the regular sessions for the conference are 75-90 minutes long.  For an extra fee, you can attend a full-day session on a single topic during a pre- or post-conference training day.  I had been meaning for several months to dive in and learn PowerShell, but just never seemed to find (or make) the time for it, so when I saw this was one of the all-day sessions, and I was planning to be there on Monday anyway, I decided to go for it.  And it was well worth it!  I definitely came out of there with a good foundation to build my own PowerShell scripts, plus several sample scripts that he showed which already cover the first four or five things I was planning to do with PowerShell anyway.  This looks like the right tool for me to build an automated version of our software deployment process, which right now contains many repeated steps.  Thanks Allen! Service Broker with Denny Cherry (blog | Twitter).  I remembered reading Denny’s blog post on Using Service Broker instead of Replication, and ever since then I have been thinking about using this to populate a new reporting-focused Data Repository that we will be building in the near future.  When I saw he was doing this session, I thought it would be great to get more information and be able to ask the author questions.  When I brought this idea back to my boss, he really liked it, as we had previously been discussing doing nightly data loads, with an option to manually trigger a mid-day load if up-to-the-minute data was needed for something.  If we go the Service Broker route, we can keep the Repository current in near real-time.  Hooray! DBA Mythbusters with Paul Randal (blog | Twitter).  Even though I read every one of the posts in Paul’s blog series of the same name, I had to go see the legend in person.  It was great, and I still learned something new! How to Conduct Effective Meetings with Joe Webb (blog | Twitter).  I always like to sit in on a session that Joe does.  I met Joe several years ago when both he and Bill Graziano were on the PASS Board of Directors together, and we have kept in touch.  Joe is very well-spoken and has great experience with both SQL Server and business.  And we could certainly use some pointers at my work (probably yours, too) on making our meetings more effective and to run on-time.  Of course, now that I’m the Chapter Leader for the Professional Development virtual chapter, I also had to sit in on this ProfDev session and recruit Joe to do a presentation or two for the chapter next year. Query Optimization with David DeWitt.  Anyone who has seen Dr. David DeWitt present the 3rd keynote at a PASS Summit over the last three years knows what a great time it is to sit and listen to him make some really complicated and advanced topic easy to understand (although it still makes your head hurt).  It still amazes me that the simple two-table join query from pubs that he used in his example can possibly have 22 million possible physical query plans.  Ouch! Exhibit Hall:  This year I spent more serious time in the exhibit hall than any year past.  I have talked my boss into making a significant (for us) investment in monitoring tools next year, and this was a great opportunity to talk with all the big-hitters.  Readers of mine may recall that I fell in love with the SQL Sentry Power Suite several months ago and wrote a blog entry about it just from the trial version.  Well as things turned out, short-term budget priorities shifted, and we weren’t able to make the purchase then.  I have it in the budget for next year, but since I was going to the Summit, my boss wanted me to look at the other options to see if this was really the one that we wanted.  I spent a couple of hours talking with representatives from Red-Gate, Idera, Confio, and Quest about their offerings, and giving them each the same 3 scenarios that I wanted to be able to accomplish based on the questions and issues that arise in our company.  It was interesting to discover the different approaches or “world view” that each vendor takes to the subject of performance monitoring and troubleshooting.  I may write a separate article that goes into this in more depth, but the product that best aligned with our point of view, and met the current needs we have is still the SQL Sentry Power Suite.  I’m not saying that the others are bad or wrong or anything like that, just that the way they tackled the issue did not align as well with our particular needs as does SQL Sentry’s product.  And that was something I learned too, when you go shopping for these products, you really need to know what you want to get from them.  It’s best if you have a few example scenarios from work that you can use to test out how well each tool fits your particular needs. Overall, another GREAT event.  I can’t wait to get the DVDs so I can sit in on a bunch of other sessions that I couldn’t get to because I was in one of the ones above.  And I can hardly wait until next year!

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• A Closer Look at the HiddenInput Attribute in MVC 2

  - by Steve Michelotti

  MVC 2 includes an attribute for model metadata called the HiddenInput attribute. The typical usage of the attribute looks like this (line #3 below): 1: public class PersonViewModel 2: { 3: [HiddenInput(DisplayValue = false)] 4: public int? Id { get; set; } 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: } So if you displayed your PersonViewModel with Html.EditorForModel() or Html.EditorFor(m => m.Id), the framework would detect the [HiddenInput] attribute metadata and produce HTML like this: 1: <input id="Id" name="Id" type="hidden" value="21" /> This is pretty straight forward and allows an elegant way to keep the technical key for your model (e.g., a Primary Key from the database) in the HTML so that everything will be wired up correctly when the form is posted to the server and of course not displaying this value visually to the end user. However, when I was giving a recent presentation, a member of the audience asked me (quite reasonably), “When would you ever set DisplayValue equal to true when using a HiddenInput?” To which I responded, “Well, it’s an edge case. There are sometimes when…er…um…people might want to…um…display this value to the user.” It was quickly apparent to me (and I’m sure everyone else in the room) what a terrible answer this was. I realized I needed to have a much better answer here. First off, let’s look at what is produced if we change our view model to use “true” (which is equivalent to use specifying [HiddenInput] since “true” is the default) on line #3: 1: public class PersonViewModel 2: { 3: [HiddenInput(DisplayValue = true)] 4: public int? Id { get; set; } 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: } Will produce the following HTML if rendered from Htm.EditorForModel() in your view: 1: <div class="editor-label"> 2: <label for="Id">Id</label> 3: </div> 4: <div class="editor-field"> 5: 21<input id="Id" name="Id" type="hidden" value="21" /> 6: <span class="field-validation-valid" id="Id_validationMessage"></span> 7: </div> The key is line #5. We get the text of “21” (which happened to be my DB Id in this instance) and also a hidden input element (again with “21”). So the question is, why would one want to use this? The best answer I’ve found is contained in this MVC 2 whitepaper: When a view lets users edit the ID of an object and it is necessary to display the value as well as to provide a hidden input element that contains the old ID so that it can be passed back to the controller. Well, that actually makes sense. Yes, it seems like something that would happen *rarely* but, for those instances, it would enable them easily. It’s effectively equivalent to doing this in your view: 1: <%: Html.LabelFor(m => m.Id) %> 2: <%: Model.Id %> 3: <%: Html.HiddenFor(m => m.Id) %> But it’s allowing you to specify it in metadata on your view model (and thereby take advantage of templated helpers like Html.EditorForModel() and Html.EditorFor()) rather than having to explicitly specifying everything in your view.

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• Geocaching - World wide treasure hunt

  I'm not quite sure how I came across this topic but actually I find it absolutely interesting, challenging and most of all a great fun for the family and friends. The interesting part is for sure that you can follow other peoples treasures and their preferred locations where a cache might be hidden. Of course, it wont be easy to find a cache after all. Sometimes there are even 'mystery caches' which have either riddles, further instructions or little brain games for you in order to find the actual cache - that's the challenge. And last but not least, those caches are hidden outdoor. A great experience to explore nature either on your own, or your family especially with children, or as a treasure hunting pack with a couple of friends. What is geocaching? It's a high-tech outdoor treasure hunting game that's a great way to explore the world with friends, family or on your own. Participants use GPS-enabled devices to locate hidden containers called geocaches. There are over one million geocaches hidden around the world today, waiting for you to find them. Visit Geocaching.com to search for geocaches near you.(Source: Referral Email of geocaching.com) Checkout the Geocaching 101 for further details and information. They also provide a video channel on YouTube. Which equipment do I need? Any GPS-enabled device is sufficient to go onto the hunt. I'm going to start our geocaching experience equipped with my Samsung Galaxy Tab. Additionally, I installed a geocaching.com client called c:geo that hopefully assists me soon. Combined with a map app like Google Maps and a nice Compass app you should be fully equipped and ready to go. I guess, that even a car navigation system is perfect for that task. Later on, with more experience and demand for technology (or precision) it might be interesting to opt-in for a pure GPS device, like a Garmin or any other brand on the market. {loadposition content_adsense} What is a geocache and what does it contain? In its simplest form, a cache always contains a logbook or logsheet for you to log your find. Larger caches may contain a logbook and any number of items. These items turn the adventure into a true treasure hunt. You never know what the cache owner or visitors to the cache may have left for you to enjoy. Remember, if you take something, leave something of equal or greater value in return. It is recommended that items in a cache be individually packaged in a clear, zipped plastic bag to protect them from the elements. Finding your first geocache Well, first you have to have interest to pick up the challenge. Then you have to check out the Geocache directory on geocaching.com. They have recommendations for beginner's caches but you are free to choose any. Actually, we have a Mystery Cache very close to our base, and I guess that we are going for that one on our first trip. Anyway, there is a very informative guide on the website which should answer all your questions about starting your new outdoor adventure. For sure, it's going to be rewarding. Team up with friends and family Especially as a beginner there might be misunderstandings in handling the GPS coordinates, the compass, or the map, and even finding the container at the documented position isn't easy in the first place. Luckily, there are logbook reports online from other hunters, and most of the time there are even 'spoiler' images available. But also bear in mind, that a geocache might have been removed or is lost due to unconscious people or whatever other reasons. Don't be disappointed in case that you can't find anything... There be nothing anymore. A general recommendation in this case would be to replace the missing container with a new one, and give feedback to the original owner about the state of that particular location. After all, it's about fun and active participation in a world-wide community. Geocaches in Mauritius? Yes, there are currently about 45 geocaches spread all over the island, and even a single in Rodriguez - that's gonna be a tough one. Hopefully, we will get increasing numbers as Geocaching.com allows, no better, even encourages you to hide new containers at your locations of choice. I think this is going to be real fun for us during the upcoming weeks and months. Especially, when we are travelling to other countries and transfer so-called trackable items between geocaches. On my first impression, Geocaching.com seems to be very mature, open and community-oriented. There are literally hundreds of thousands geocache 'hunters' all over the world. And usually finding a container remote from your home is very rewarding. I'll keep you updated in these matters during the next months to come...

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• SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28

  - by pinaldave

  CXPACKET has to be most popular one of all wait stats. I have commonly seen this wait stat as one of the top 5 wait stats in most of the systems with more than one CPU. Books On-Line: Occurs when trying to synchronize the query processor exchange iterator. You may consider lowering the degree of parallelism if contention on this wait type becomes a problem. CXPACKET Explanation: When a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. There is an organizer/coordinator thread (thread 0), which takes waits for all the threads to complete and gathers result together to present on the client’s side. The organizer thread has to wait for the all the threads to finish before it can move ahead. The Wait by this organizer thread for slow threads to complete is called CXPACKET wait. Note that not all the CXPACKET wait types are bad. You might experience a case when it totally makes sense. There might also be cases when this is unavoidable. If you remove this particular wait type for any query, then that query may run slower because the parallel operations are disabled for the query. Reducing CXPACKET wait: We cannot discuss about reducing the CXPACKET wait without talking about the server workload type. OLTP: On Pure OLTP system, where the transactions are smaller and queries are not long but very quick usually, set the “Maximum Degree of Parallelism” to 1 (one). This way it makes sure that the query never goes for parallelism and does not incur more engine overhead. EXEC sys.sp_configure N'cost threshold for parallelism', N'1' GO RECONFIGURE WITH OVERRIDE GO Data-warehousing / Reporting server: As queries will be running for long time, it is advised to set the “Maximum Degree of Parallelism” to 0 (zero). This way most of the queries will utilize the parallel processor, and long running queries get a boost in their performance due to multiple processors. EXEC sys.sp_configure N'cost threshold for parallelism', N'0' GO RECONFIGURE WITH OVERRIDE GO Mixed System (OLTP & OLAP): Here is the challenge. The right balance has to be found. I have taken a very simple approach. I set the “Maximum Degree of Parallelism” to 2, which means the query still uses parallelism but only on 2 CPUs. However, I keep the “Cost Threshold for Parallelism” very high. This way, not all the queries will qualify for parallelism but only the query with higher cost will go for parallelism. I have found this to work best for a system that has OLTP queries and also where the reporting server is set up. Here, I am setting ‘Cost Threshold for Parallelism’ to 25 values (which is just for illustration); you can choose any value, and you can find it out by experimenting with the system only. In the following script, I am setting the ‘Max Degree of Parallelism’ to 2, which indicates that the query that will have a higher cost (here, more than 25) will qualify for parallel query to run on 2 CPUs. This implies that regardless of the number of CPUs, the query will select any two CPUs to execute itself. EXEC sys.sp_configure N'cost threshold for parallelism', N'25' GO EXEC sys.sp_configure N'max degree of parallelism', N'2' GO RECONFIGURE WITH OVERRIDE GO Read all the post in the Wait Types and Queue series. Additionally a must read comment of Jonathan Kehayias. Note: The information presented here is from my experience and I no way claim it to be accurate. I suggest you all to read the online book for further clarification. All the discussion of Wait Stats over here is generic and it varies from system to system. It is recommended that you test this on the development server before implementing on the production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• WEB203 &ndash; Jump into Silverlight!&hellip; and Become Effective Immediately with Tim Huckaby, Fou

  - by Robert Burger

  Getting ready for the good stuff. Definitely wish there were more Silverlight and WCF RIA sessions, but this is a start.  Was lucky to get a coveted power-enabled seat.  Luckily, due to my trustily slow Verizon data card, I can get these notes out amidst a total Internet outage here.  This is the second breakout session of the day, and is by far standing-room only.  I stepped out before the session started to get a cool Diet COKE and wouldn’t have gotten back in if I didn’t already have a seat. Tim says this is an intro session and that he’s been begging for intro sessions at TechEd for years and that by looking at this audience, he thinks the demand is there.  Admittedly, I didn’t know this was an intro session, or I might have gone elsewhere.  But, it was the very first Silverlight session, so I had to be here. Tim says he will be providing a very good comprehensive reference application at the end of the presentation.  He has just demoed it, and it is a full CRUD-based Sales Manager application based on…  AdventureWorks! Session Agenda What it is / How to get started Declarative Programming Layout and Controls, Events and Commands Working with Data Adding Style to Your Application   Silverlight…  “WPF Light” Why is the download 4.2MB?  Because the direct competitor is a 4.2MB download.  There is no technical reason it is not the entire framework.  It is purely to “be competitive”.   Getting Started Get all of the following downloads from www.silverlight.net/getstarted Install VS2010 or Visual Web Developer Express 2010 Install Silverlight 4 Tools for VS2010 Install Expression Blend 4 Install the Silverlight 4 Toolkit   Reference Application Features Uses MVVM pattern – a way to move data access code that would normally be inline within the UI and placing it in nice data access libraries Images loaded dynamically from the database, converting GIF to PNG because Silverlight does not support GIF. LINQ to SQL is the data access model WCF is the data provider and is using binary message encoding   Declarative Programming XAML replaces code for UI representation Attributes control Layout and Style Event handlers wired-up in XAML Declarative Data Binding   Layout Overview Content rendering flows inside of parent Fixed positioning (Canvas) is seldom used Panels are used to house content Margins and Padding over fixed size   Panels StackPanel – Arranges child elements into a single line oriented horizontally or vertically Grid – A flexible grid are that consists of rows and columns Canvas – An are where positions are specifically fixed WrapPanel (in Toolkit) – Positions child elements in sequential position left to right and top to bottom. DockPanel (in Toolkit) – Positions child controls within a dockable area   Positioning Horizontal and Vertical Alignment Margin – Separates an element from neighboring elements Padding – Enlarges the effective size of an element by a thickness   Controls Overview Not all controls created equal Silverlight, as a subset of WPF, so many WPF controls do not exist in the core Siverlight release Silverlight Toolkit continues to add controls, but are released in different quality bands Plenty of good 3rd party controls to fill the gaps Windows Phone 7 is to have 95% of controls available in Silverlight Core and Toolkit.   Events and Commands Standard .NET Events Routed Events Commands – based on the ICommand interface – logical action that can be invoked in several ways   Adding Style to Your Application Resource Dictionaries – Contains a hash table of key/value pairs.  Silverlight can only use Static Resources whereas WPF can also use Dynamic Resources Visual State Manager Silverlight 4 supports Implicit styles ResourceDictionary.MergedDictionaries combines many different file-based resources   Downloads

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• BPM Suite 11gR1 Released

  - by Manoj Das

  This morning (April 27th, 2010), Oracle BPM Suite 11gR1 became available for download from OTN and eDelivery. If you have been following our plans in this area, you know that this is the release unifying BEA ALBPM product, which became Oracle BPM10gR3, with the Oracle stack. Some of the highlights of this release are: BPMN 2.0 modeling and simulation Web based Process Composer for BPMN and Rules authoring Zero-code environment with full access to Oracle SOA Suite’s rich set of application and other adapters Process Spaces – Out-of-box integration with Web Center Suite Process Analytics – Native process cubes as well as integration with Oracle BAM You can learn more about this release from the documentation. Notes about downloading and installing Please note that Oracle BPM Suite 11gR1 is delivered and installed as part of SOA 11.1.1.3.0, which is a sparse release (only incremental patch). To install: Download and install SOA 11.1.1.2.0, which is a full release (you can find the bits at the above location) Download and install SOA 11.1.1.3.0 During configure step (using the Fusion Middleware configuration wizard), use the Oracle Business Process Management template supplied with the SOA Suite11g (11.1.1.3.0) If you plan to use Process Spaces, also install Web Center 11.1.1.3.0, which also is delivered as a sparse release and needs to be installed on top of Web Center 11.1.1.2.0 Some early feedback We have been receiving very encouraging feedback on this release. Some quotes from partners are included below: “I just attended a preview workshop on BPM Studio, Oracle's BPMN 2.0 tool, held by Clemens Utschig Utschig from Oracle HQ. The usability and ease to get started are impressive. In the business view analysts can intuitively start modeling, then developers refine in their own, more technical view. The BPM Studio sets itself apart from pure play BPMN 2.0 tools by being seamlessly integrated inside a holistic SOA / BPM toolset: BPMN models are placed in SCA-Composites in SOA Suite 11g. This allows to abstract away the complexities of SOA integration aspects from business process aspects. For UIs in BPMN tasks, you have the richness of ADF 11g based Frontends. With BPM Studio we architects have a new modeling and development IDE that gives us interesting design challenges to grasp and elaborate, since many things BPMN 2.0 are different from good ol' BPEL. For example, for simple transformations, you don't use BPEL "assign" any more, but add the transformation directly to the service call. There is much less XPath involved. And, there is no translation from model to BPEL code anymore, so the awkward process model to BPEL roundtrip, which never really worked as well as it looked on marketing slides, is obsolete: With BPMN 2.0 "the model is the code". Now, these are great times to start the journey into BPM! Some tips: Start Projects smoothly, with initial processes being not overly complex and not using the more esoteric areas of BPMN, to manage the learning path and to stay successful with each iteration. Verify non functional requirements by conducting performance and load tests early. As mentioned above, separate all technical integration logic into SOA Suite or Oracle Service Bus. And - share your experience!” Hajo Normann, SOA Architect - Oracle ACE Director - Co-Leader DOAG SIG SOA   "Reuse of components across the Oracle 11G Fusion Middleware stack, like for instance a Database Adapter, is essential. It improves stability and predictability of the solution. BPM just is one of the components plugging into the stack and reuses all other components." Mr. Leon Smiers, Oracle Solution Architect, Capgemini   “I had the opportunity to follow a hands-on workshop held by Clemens for Oracle partners and I was really impressed of the overall offering of BPM11g. BPM11g allows the execution of BPMN 2.0 processes, without having to transform/translate them first to BPEL in order to be executable. The fact that BPMN uses the same underlying service infrastructure of SOA Suite 11g has a lot of benefits for us already familiar with SOA Suite 11g. BPMN is just another SCA component within a SCA composite and can (re)use all the existing components like Rules, Human Workflow, Adapters and Mediator. I also like the fact that BPMN runs on the same service engine as BPEL. By that all known best practices for making a BPEL  process reliable are valid for BPMN processes as well. Last but not least, BPMN is integrated into the superior end-to-end tracing of SOA Suite 11g. With BPM11g, Oracle offers a very competitive product which will have a big effect on the IT market. Clemens and Jürgen: Thanks for the great workshop! I’m really looking forward to my first project using Oracle BPM11g!” Guido Schmutz, Technology Manager / Oracle ACE Director for Fusion Middleware and SOA, Company:  Trivadis Some earlier feedback were summarized in this post.

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• Simple-Talk development: a quick history lesson

  - by Michael Williamson

  Up until a few months ago, Simple-Talk ran on a pure .NET stack, with IIS as the web server and SQL Server as the database. Unfortunately, the platform for the site hadn’t quite gotten the love and attention it deserved. On the one hand, in the words of our esteemed editor Tony “I’d consider the current platform to be a “success”; it cost $10K, has lasted for 6 years, was finished, end to end in 6 months, and although we moan about it has got us quite a long way.” On the other hand, it was becoming increasingly clear that it needed some serious work. Among other issues, we had authors that wouldn’t blog because our current blogging platform, Community Server, was too painful for them to use. Forgetting about Simple-Talk for a moment, if you ask somebody what blogging platform they’d choose, the odds are they’d say WordPress. Regardless of its technical merits, it’s probably the most popular blogging platform, and it certainly seemed easier to use than Community Server. The issue was that WordPress is normally hosted on a Linux stack running PHP, Apache and MySQL — quite a difference from our Microsoft technology stack. We certainly didn’t want to rewrite the entire site — we just wanted a better blogging platform, with the rest of the existing, legacy site left as is. At a very high level, Simple-Talk’s technical design was originally very straightforward: when your browser sends an HTTP request to Simple-Talk, IIS (the web server) takes the request, does some work, and sends back a response. In order to keep the legacy site running, except with WordPress running the blogs, a different design is called for. We now use nginx as a reverse-proxy, which can then delegate requests to the appropriate application: So, when your browser sends a request to Simple-Talk, nginx takes that request and checks which part of the site you’re trying to access. Most of the time, it just passes the request along to IIS, which can then respond in much the same way it always has. However, if your request is for the blogs, then nginx delegates the request to WordPress. Unfortunately, as simple as that diagram looks, it hides an awful lot of complexity. In particular, the legacy site running on IIS was made up of four .NET applications. I’ve already mentioned one of these applications, Community Server, which handled the old blogs as well as managing membership and the forums. We have a couple of other applications to manage both our newsletters and our articles, and our own custom application to do some of the rendering on the site, such as the front page and the articles. When I say that it was made up of four .NET applications, this might conjure up an image in your mind of how they fit together: You might imagine four .NET applications, each with their own database, communicating over well-defined APIs. Sadly, reality was a little disappointing: We had four .NET applications that all ran on the same database. Worse still, there were many queries that happily joined across tables from multiple applications, meaning that each application was heavily dependent on the exact data schema that each other application used. Add to this that many of the queries were at least dozens of lines long, and practically identical to other queries except in a few key spots, and we can see that attempting to replace one component of the system would be more than a little tricky. However, the problems with the old system do give us a good place to start thinking about desirable qualities from any changes to the platform. Specifically: Maintainability — the tight coupling between each .NET application made it difficult to update any one application without also having to make changes elsewhere Replaceability — the tight coupling also meant that replacing one component wouldn’t be straightforward, especially if it wasn’t on a similar Microsoft stack. We’d like to be able to replace different parts without having to modify the existing codebase extensively Reusability — we’d like to be able to combine the different pieces of the system in different ways for different sites Repeatable deployments — rather than having to deploy the site manually with a long list of instructions, we should be able to deploy the entire site with a single command, allowing you to create a new instance of the site easily whether on production, staging servers, test servers or your own local machine Testability — if we can deploy the site with a single command, and each part of the site is no longer dependent on the specifics of how every other part of the site works, we can begin to run automated tests against the site, and against individual parts, both to prevent regressions and to do a little test-driven development In the next part, I’ll describe the high-level architecture we now have that hopefully brings us a little closer to these five traits.

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• Enterprise 2.0 - Connecting People, Processes & Content

  - by kellsey.ruppel(at)oracle.com

  With recent technological advances, the Internet is changing. When users head to the web, they are no longer just looking for information from a simple text and picture based website. Users want a more interactive experience - they want to participate, to share their views and get the feedback of others. And this is precisely what Web 2.0 technology addresses. Web 2.0 is about web applications that facilitate interactive information sharing, user-centered design and collaboration on the World Wide Web. Web 2.0 technology is everywhere on the Internet and is radically changing the speed and medium in which we interact and communicate. There are thousands of examples in the consumer world of Web 2.0 applications, technologies and solutions at work. You might be familiar with some of them...blogs, wikis (Wikipedia), Twitter, Facebook, LinkedIn - these are all examples of Web 2.0. And these technologies are transforming our world into a real-time, participation-oriented, user-driven, content-centric world. With all of these Web 2.0 solutions it's about the user, the consumer and all the content they are generating. It's a world full of online communities where people share and participate. We're not talking about disseminating information top-down , nor is it a bottom-up fight. Everyone has an equal opportunity to participate and share. The more you participate, the more you share, the more valued you are in the community. The web is not just a collection of documents online. It is the social web.  For the active users in the community, staying connected becomes critically important so they can participate at anytime and from anywhere. And because feedback and interaction are so critical, time is of the essence. When everyone is providing immediate responses, you feel the urge to do the same. Hence everything needs to be done right now, together...and collaboratively. With all the content being generated online by users, there is complete information overload out there. (That's a good thing for Google). But...it's no longer just about search. Sometimes you want the information to just come to you. Recommendations and discovery engines will deliver you more applicable results than a non-contextual search. How many of you have heard about a news headline on Facebook as part of your feed before you read the paper or see it on TV? This is how the new generation of workers live their daily lives...and as they enter the workforce, these trends and technologies are showing up in the enterprise too. A lot of the Web 2.0 technologies and solutions in the consumer world are geared for just that....consumers. But the core concepts that put them into the Web 2.0 category can be applied to the enterprise as well. And that is what we mean when we talk about Enterprise 2.0. Enterprise 2.0 is the use of Web 2.0 tools and technologies in the workplace.  It provides a modern user experience by connecting the people, content and business processes inside and outside the enterprise. Enterprise 2.0 empowers users to collaborate more effectively, find and share information in the proper content and improves the overall business processes which they participate in. As we head into 2011, is your organization using Enterprise 2.0 capabilities to the fullest? Are you connecting your people, processes and content together to provide a modern user experience?

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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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• The Krewe App Post-Mortem

  - by Chris Gardner

  Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2014/05/23/the-krewe-app-post-mortem.aspxNow that teched has come and gone, I thought I would use this opportunity to do a little post-mortem on The Krewe app. It is one thing to test the app at home. It is a completely different animal to see how it responds in the environment TechEd creates. At a future time, I will list all the things that I would like to change with the app. At this point, I will find some good way to get community feedback. I want to break all this down screen by screen. We'll start with the screen I got right. The first of these is the events calendar. This is the one screen that, to you guys, just worked. However, there was an issue here. When I wrote v1 for last year, I was lazy and placed everything in CST. This caused problems with the achievements, which I will explain later. Furthermore, the event locations were not check-in locations. This created another problem with the achievements. Next, we get to the Twitter page. For what this page does, it works great. For those that don't know, I have an Azure Worker Role that polls Twitter pretty close to the rate limit. I cache these results in my database, and serve them upon request. This gives me great control over the content. I just have to remember to flush past tweets after a period, to save database growth. The next screen is the check-in screen. This screen has been the bane of my existence since I first created the thing. Last year, I used a background task to check people out of locations after they traveled. This year, I removed the background task in favor of a foursquare model. You are checked out after 3 hours or when you check-in to some other location. This seemed to work well, until those pesky achievements came into the mix. Again, more on this later. Next, I want to address the Connect and Connections screens together. I wanted to use some of the capabilities of the phone, and NFC seemed a natural choice. From this, I came up with the gamification aspects of the app. Since we are, fundamentally, a networking organization, I wanted to encourage people to actually network. Users could make and share a profile, similar to a virtual business card. I just had to figure out how to get people to use the feature. Why not just give someone a business card? Thus, the achievements were born. This was such a good idea. It would have been a great idea, if I have come up with it about two months earlier... When I came up with these ideas, I had about 2 weeks to implement them. Version 1 of the app was, basically, a pure consumption app. We provided data and centralized it. With version 2, the app became a much more interactive experience. The API was not ready for this change in such a short period of time. Most of this became apparent when I started implementing the achievements. The achievements based on count and specific person when fairly easy. The problem came with tying them to locations and events. This took some true SQL kung fu. This also showed me the rookie mistake of putting CST, not UTC, in the database. Once I got all of that cleaned up, I had to find a way to get the achievement system to talk to the phone. I knew I needed to be able to dynamically add achievements. I wouldn't know the precise location of some things until I got to Houston. I wanted the server to approve the achievements. This, unfortunately, required a decent data connection. Some achievements required GPS levels of location accuracy in areas of network triangulation. All of this became a huge nightmare. My flagship feature was based on some silly assumptions. Still, I managed to get 31 people to get the first achievement (Make 1 Connection.) Quite a few of those managed to get to the higher levels. Soon, I will post a list of the feature and changes that need to happen to the API. This includes things like proper objects for communication, geo-fencing, and caching. However, that is for another day.

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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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• Demystified - BI in SharePoint 2010

  - by Sahil Malik

  Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). Frequently, my clients ask me if there is a good guide on deciphering the seemingly daunting choice of products from Microsoft when it comes to business intelligence offerings in a SharePoint 2010 world. These are all described in detail in my book, but here is a one (well maybe two) page executive overview. Microsoft Excel: Yes, Microsoft Excel! Your favorite and most commonly used in the world database. No it isn’t a database in technical pure definitions, but this is the most commonly used ‘database’ in the world. You will find many business users craft up very compelling excel sheets with tonnes of logic inside them. Good for: Quick Ad-Hoc reports. Excel 64 bit allows the possibility of very large datasheets (Also see 32 bit vs 64 bit Office, and PowerPivot Add-In below). Audience: End business user can build such solutions. Related technologies: PowerPivot, Excel Services Microsoft Excel with PowerPivot Add-In: The powerpivot add-in is an extension to Excel that adds support for large-scale data. Think of this as Excel with the ability to deal with very large amounts of data. It has an in-memory data store as an option for Analysis services. Good for: Ad-hoc reporting and logic with very large amounts of data. Audience: End business user can build such solutions. Related technologies: Excel, and Excel Services Excel Services: Excel Services is a Microsoft SharePoint Server 2010 shared service that brings the power of Excel to SharePoint Server by providing server-side calculation and browser-based rendering of Excel workbooks. Thus, excel sheets can be created by end users, and published to SharePoint server – which are then rendered right through the browser in read-only or parameterized-read-only modes. They can also be accessed by other software via SOAP or REST based APIs. Good for: Sharing excel sheets with a larger number of people, while maintaining control/version control etc. Sharing logic embedded in excel sheets with other software across the organization via REST/SOAP interfaces Audience: End business users can build such solutions once your tech staff has setup excel services on a SharePoint server instance. Programmers can write software consuming functionality/complex formulae contained in your sheets. Related technologies: PerformancePoint Services, Excel, and PowerPivot. Visio Services: Visio Services is a shared service on the Microsoft SharePoint Server 2010 platform that allows users to share and view Visio diagrams that may or may not have data connected to them. Connected data can update these diagrams allowing a visual/graphical view into the data. The diagrams are viewable through the browser. They are rendered in silverlight, but will automatically down-convert to .png formats. Good for: Showing data as diagrams, live updating. Comes with a developer story. Audience: End business users can build such solutions once your tech staff has setup visio services on a SharePoint server instance. Developers can enhance the visualizations Related Technologies: Visio Services can be used to render workflow visualizations in SP2010 Reporting Services: SQL Server reporting services can integrate with SharePoint, allowing you to store reports and data sources in SharePoint document libraries, and render these reports and associated functionality such as subscriptions through a SharePoint site. In SharePoint 2010, you can also write reports against SharePoint lists (access services uses this technique). Good for: Showing complex reports running in a industry standard data store, such as SQL server. Audience: This is definitely developer land. Don’t expect end users to craft up reports, unless a report model has previously been published. Related Technologies: PerformancePoint Services PerformancePoint Services: PerformancePoint Services in SharePoint 2010 is now fully integrated with SharePoint, and comes with features that can either be used in the BI center site definition, or on their own as activated features in existing site collections. PerformancePoint services allows you to build reports and dashboards that target a variety of back-end datasources including: SQL Server reporting services, SQL Server analysis services, SharePoint lists, excel services, simple tables, etc. Using these you have the ability to create dashboards, scorecards/kpis, and simple reports. You can also create reports targeting hierarchical multidimensional data sources. The visual decomposition tree is a new report type that lets you quickly breakdown multi-dimensional data. Good for: Mostly everything :), except your wallet – it’s not free! But this is the most comprehensive offering. If you have SharePoint server, forget everything and go with performance point. Audience: Developers need to setup the back-end sources, manageability story. DBAs need to setup datawarehouses with cubes. Moderately sophisticated business users, or developers can craft up reports using dashboard designer which is a click-once App that deploys with PerformancePoint Related Technologies: Excel services, reporting services, etc.   Other relevant technologies to know about: Business Connectivity Services: Allows for consumption of external data in SharePoint as columns or external lists. This can be paired with one or more of the above BI offerings allowing insight into such data. Access Services: Allows the representation/publishing of an access database as a SharePoint 2010 site, leveraging many SharePoint features. Reporting services is used by Access services. Secure Store Service: The SP2010 Secure store service is a replacement for the SP2007 single sign on feature. This acts as a credential policeman providing credentials to various applications running with SharePoint. BCS, PerformancePoint Services, Excel Services, and many other apps use the SSS (Secure Store Service) for credential control. Comment on the article ....

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• How Can I Improve This Card-Game AI?

  - by James Burgess

  Let me get this out there before anything else: this is a learning exercise for me. I am not a game developer by trade or hobby (at least, not seriously) and am purely delving into some AI- and 3D-related topics to broaden my horizons a bit. As part of the learning experience, I thought I'd have a go at developing a basic card game AI. I selected Pit as the card game I was going to attempt to emulate (specifically, the 'bull and bear' variation of the game as mentioned in the link above). Unfortunately, the rule-set that I'm used to playing with (an older version of the game) isn't described. The basics of it are: The number of commodities played with is equal to the number of players. The bull and bear cards are included. All but two players receive 8 cards, two receive 9 cards. A player can win the round with 7 + bull, 8, or 8 + bull (receiving double points). The bear is a penalty card. You can trade up to a maximum of 4 cards at a time. They must all be of the same type, but can optionally include the bull or bear (so, you could trade A, A, A, Bull - but not A, B, A, Bull). For those who have played the card game, it will probably have been as obvious to you as it was to me that given the nature of the game, gameplay would seem to resemble a greedy algorithm. With this in mind, I thought it might simplify my AI experience somewhat. So, here's what I've come up with for a basic AI player to play Pit... and I'd really just like any form of suggestion (from improvements to reading materials) relating to it. Here it is in something vaguely pseudo-code-ish ;) While AI does not hold 7 similar + bull, 8 similar, or 8 similar + bull, do: 1. Establish 'target' hand, by seeing which card AI holds the most of. 2. Prepare to trade next-most-numerous card type in a trade (max. held, or 4, whichever is fewer) 3. If holding the bear, add to (if trading <=3 cards) or replace in (if trading 4 cards) hand. 4. Offer cards for trade. 5. If cards are accepted for trade within X turns, continue (clearing 'failed card types'). Otherwise: a. If only one card remains in the trade, go to #6. Otherwise: i. Remove one non-penalty card from the trade. ii. Return to #5. 6. Add card type to temporary list of failed card types. 7. Repeat from #2 (excluding 'failed card types'). I'm aware this is likely to be a sub-optimal way of solving the problem, but that's why I'm posting this question. Are there any AI- or algorithm-related concepts that I've missed and should be incorporating to make a better AI? Additionally, what are the flaws with my AI at present (I'm well aware it's probably far from complete)? Thanks in advance!

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• Talend Enterprise Data Integration overperforms on Oracle SPARC T4

  - by Amir Javanshir

  The SPARC T microprocessor, released in 2005 by Sun Microsystems, and now continued at Oracle, has a good track record in parallel execution and multi-threaded performance. However it was less suited for pure single-threaded workloads. The new SPARC T4 processor is now filling that gap by offering a 5x better single-thread performance over previous generations. Following our long-term relationship with Talend, a fast growing ISV positioned by Gartner in the “Visionaries” quadrant of the “Magic Quadrant for Data Integration Tools”, we decided to test some of their integration components with the T4 chip, more precisely on a T4-1 system, in order to verify first hand if this new processor stands up to its promises. Several tests were performed, mainly focused on: Single-thread performance of the new SPARC T4 processor compared to an older SPARC T2+ processor Overall throughput of the SPARC T4-1 server using multiple threads The tests consisted in reading large amounts of data --ten's of gigabytes--, processing and writing them back to a file or an Oracle 11gR2 database table. They are CPU, memory and IO bound tests. Given the main focus of this project --CPU performance--, bottlenecks were removed as much as possible on the memory and IO sub-systems. When possible, the data to process was put into the ZFS filesystem cache, for instance. Also, two external storage devices were directly attached to the servers under test, each one divided in two ZFS pools for read and write operations. Multi-thread: Testing throughput on the Oracle T4-1 The tests were performed with different number of simultaneous threads (1, 2, 4, 8, 12, 16, 32, 48 and 64) and using different storage devices: Flash, Fibre Channel storage, two stripped internal disks and one single internal disk. All storage devices used ZFS as filesystem and volume management. Each thread read a dedicated 1GB-large file containing 12.5M lines with the following structure: customerID;FirstName;LastName;StreetAddress;City;State;Zip;Cust_Status;Since_DT;Status_DT 1;Ronald;Reagan;South Highway;Santa Fe;Montana;98756;A;04-06-2006;09-08-2008 2;Theodore;Roosevelt;Timberlane Drive;Columbus;Louisiana;75677;A;10-05-2009;27-05-2008 3;Andrew;Madison;S Rustle St;Santa Fe;Arkansas;75677;A;29-04-2005;09-02-2008 4;Dwight;Adams;South Roosevelt Drive;Baton Rouge;Vermont;75677;A;15-02-2004;26-01-2007 […] The following graphs present the results of our tests: Unsurprisingly up to 16 threads, all files fit in the ZFS cache a.k.a L2ARC : once the cache is hot there is no performance difference depending on the underlying storage. From 16 threads upwards however, it is clear that IO becomes a bottleneck, having a good IO subsystem is thus key. Single-disk performance collapses whereas the Sun F5100 and ST6180 arrays allow the T4-1 to scale quite seamlessly. From 32 to 64 threads, the performance is almost constant with just a slow decline. For the database load tests, only the best IO configuration --using external storage devices-- were used, hosting the Oracle table spaces and redo log files. Using the Sun Storage F5100 array allows the T4-1 server to scale up to 48 parallel JVM processes before saturating the CPU. The final result is a staggering 646K lines per second insertion in an Oracle table using 48 parallel threads. Single-thread: Testing the single thread performance Seven different tests were performed on both servers. Given the fact that only one thread, thus one file was read, no IO bottleneck was involved, all data being served from the ZFS cache. Read File ? Filter ? Write File: Read file, filter data, write the filtered data in a new file. The filter is set on the “Status” column: only lines with status set to “A” are selected. This limits each output file to about 500 MB. Read File ? Load Database Table: Read file, insert into a single Oracle table. Average: Read file, compute the average of a numeric column, write the result in a new file. Division & Square Root: Read file, perform a division and square root on a numeric column, write the result data in a new file. Oracle DB Dump: Dump the content of an Oracle table (12.5M rows) into a CSV file. Transform: Read file, transform, write the result data in a new file. The transformations applied are: set the address column to upper case and add an extra column at the end, which is the concatenation of two columns. Sort: Read file, sort a numeric and alpha numeric column, write the result data in a new file. The following table and graph present the final results of the tests: Throughput unit is thousand lines per second processed (K lines/second). Improvement is the % of improvement between the T5140 and T4-1. Test T4-1 (Time s.) T5140 (Time s.) Improvement T4-1 (Throughput) T5140 (Throughput) Read/Filter/Write 125 806 645% 100 16 Read/Load Database 195 1111 570% 64 11 Average 96 557 580% 130 22 Division & Square Root 161 1054 655% 78 12 Oracle DB Dump 164 945 576% 76 13 Transform 159 1124 707% 79 11 Sort 251 1336 532% 50 9 The improvement of single-thread performance is quite dramatic: depending on the tests, the T4 is between 5.4 to 7 times faster than the T2+. It seems clear that the SPARC T4 processor has gone a long way filling the gap in single-thread performance, without sacrifying the multi-threaded capability as it still shows a very impressive scaling on heavy-duty multi-threaded jobs. Finally, as always at Oracle ISV Engineering, we are happy to help our ISV partners test their own applications on our platforms, so don't hesitate to contact us and let's see what the SPARC T4-based systems can do for your application! "As describe in this benchmark, Talend Enterprise Data Integration has overperformed on T4. I was generally happy to see that the T4 gave scaling opportunities for many scenarios like complex aggregations. Row by row insertion in Oracle DB is faster with more than 650,000 rows per seconds without using any bulk Oracle capabilities !" Cedric Carbone, Talend CTO.

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• Help finding time of collision

  - by WannaBe

  I am making a simple game right now and am struggling with collision response. My goal is to someday be able to turn it into a 2D platformer but I have a long way to go. I am currently making this in JavaScript and using the canvas element so (0,0) is in the top left and positive X is to the right and positive Y is down. I read a helpful post on StackExchange that got me started on this but I can't seem to get the algorithm 100% correct. How to deal with corner collisions in 2D? I can detect the collision fine but I can't seem to get the response right. The goal is to detect which side the player hit first since minimum displacement doesn't always work. The X response seems to work fine but the Y only works when I am far from the corners. Here is a picture showing what happens Here is the code var bx = box.x; var by = box.y; var bw = box.width; var bh = box.height; var boxCenterX = bx + (bw/2); var boxCenterY = by + (bh/2); var playerCenterX = player.x + player.xvel + (player.width/2); var playerCenterY = player.y + player.yvel + (player.height/2); //left = negative and right = positve, 0 = middle var distanceXin = playerCenterX - boxCenterX; var distanceYin = playerCenterY - boxCenterY; var distanceWidth = Math.abs(distanceXin); var distanceHeight = Math.abs(distanceYin); var halfWidths = (bw/2) + (player.width/2); var halfHeights = (bh/2) + (player.height/2); if(distanceWidth < halfWidths){ //xcollision if(distanceHeight < halfHeights){ //ycollision if(player.xvel == 0){ //adjust y if(distanceYin > 0){ //bottom player.y = by + bh; player.yvel = 0; }else{ player.y = by - player.height; player.yvel = 0; } }else if(player.yvel == 0){ //adjust x if(distanceXin > 0){ //right player.x = bx + bw; player.xvel = 0; }else{ //left player.x = bx - player.width; player.xvel = 0; } }else{ var yTime = distanceYin / player.yvel; var xTime = distanceXin / player.xvel; if(xTime < yTime){ //adjust the x it collided first if(distanceXin > 0){ //right player.x = bx + bw; player.xvel = 0; }else{ //left player.x = bx - player.width; player.xvel = 0; } }else{ //adjust the y it collided first if(distanceYin > 0){ //bottom player.y = by + bh; player.yvel = 0; }else{ player.y = by - player.height; player.yvel = 0; } } } } } And here is a JSFiddle if you would like to see the problem yourself. http://jsfiddle.net/dMumU/ To recreate this move the player to here And press up and left at the same time. The player will jump to the right for some reason. Any advice? I know I am close but I can't seem to get xTime and yTime to equal what I want every time.

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• The Oracle Retail Week Awards - in review

  - by user801960

  The Oracle Retail Week Awards 2012 were another great success, building on the legacy of previous award ceremonies. Over 1,600 of the UK's top retailers gathered at the Grosvenor House Hotel and many of Europe's top retail leaders attended the prestigious Oracle Retail VIP Reception in the Grosvenor House Hotel's Red Bar. Over the years the Oracle Retail Week Awards have become a rallying point for the morale of the retail industry, and each nominated retailer served as a demonstration that the industry is fighting fit. It was an honour to speak to so many figureheads of UK - and global - retail. All of us at Oracle Retail would like to congratulate both the winners and the nominees for the awards. Retail is a cornerstone of the economy and it was inspiring to see so many outstanding demonstrations of innovation and dedication in the entries. Winners 2012   The Market Force Customer Service Initiative of the Year Winner: Dixons Retail: Knowhow Highly Commended: Hughes Electrical: Digital Switchover     The Deloitte Employer of the Year Winner: Morrisons     Growing Retailer of the Year Winner: Hallett Retail - The Concessions People Highly Commended: Blue Inc     The TCC Marketing/Advertising Campaign of the Year Winner: Sainsbury's: Feed your Family for £50     The Brandbank Multichannel Retailer of the Year Winner: Debenhams Highly Commended: Halfords     The Ashton Partnership Product Innovation of the Year Winner: Argos: Chad Valley Highly Commended: Halfords: Private label bikes     The RR Donnelley Pure-play Online Retailer of the Year Winner: Wiggle     The Hitachi Consulting Responsible Retailer of the Year Winner: B&Q: One Planet Home     The CA Technologies Retail Technology Initiative of the Year Winner: Oasis: Argyll Street flagship launch with iPad PoS     The Premier Tax Free Speciality Retailer of the Year Winner: Holland & Barrett     Store Design of the Year Winner: Next Home and Garden, Shoreham, Sussex Highly Commended: Dixons Retail, Black concept store, Birmingham Bullring     Store Manager of the Year Winner: Ian Allcock, Homebase, Aylesford Highly Commended: Darren Parfitt, Boots UK, Melton Mowbray Health Centre     The Wates Retail Destination of the Year Winner: Westfield, Stratford     The AlixPartners Emerging Retail Leader of the Year Winner: Catriona Marshall, HobbyCraft, Chief Executive     The Wipro Retail International Retailer of the Year Winner: Apple     The Clarity Search Retail Leader of the Year Winner: Ian Cheshire, Chief Executive, Kingfisher     The Oracle Retailer of the Year Winner: Burberry     Outstanding Contribution to Retail Winner: Lord Harris of Peckham     Oracle Retail and "Your Experience Platform" Technology is the key to providing that differentiated retail experience. More specifically, it is what we at Oracle call ‘the experience platform’ - a set of integrated, cross-channel business technology solutions, selected and operated by a retail business and IT team, and deployed in accordance with that organisation’s individual strategy and processes. This business systems architecture simultaneously: Connects customer interactions across all channels and touchpoints, and every customer lifecycle phase to provide a differentiated customer experience that meets consumers’ needs and expectations. Delivers actionable insight that enables smarter decisions in planning, forecasting, merchandising, supply chain management, marketing, etc; Optimises operations to align every aspect of the retail business to gain efficiencies and economies, to align KPIs to eliminate strategic conflicts, and at the same time be working in support of customer priorities.   Working in unison, these three goals not only help retailers to successfully navigate the challenges of today but also to focus on delivering that personalised customer experience based on differentiated products, pricing, services and interactions that will help you to gain market share and grow sales.  

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• JustMock is here !!

  - by mehfuzh

  As announced earlier by Hristo Kosev at Telerik blogs , we have started giving out JustMock builds from today. This is the first of early builds before the official Q2 release and we are pretty excited to get your feedbacks. Its pretty early to say anything on it. It actually depends on your feedback. To add few, with JustMock we tried to build a mocking tool with simple and intuitive syntax as possible excluding more and more noises and avoiding any smell that can be made to your code [We are still trying everyday] and we want to make the tool even better with your help. JustMock can be used to mock virtually anything. Moreover, we left an option open that it can be used to reduce / elevate the features  just though a single click. We tried to make a strong API and make stuffs fluent and guided as possible so that you never have the chance to get de-railed. Our syntax is AAA (Arrange – Act – Assert) , we don’t believe in Record – Reply model which some of the smarter mocking tools are planning to remove from their coming release or even don’t have [its always fun to lean from each other]. Overall more signals equals more complexity , reminds me of 37 signals :-). Currently, here are the things you can do with JustMock ( will cover more in-depth in coming days) Proxied mode Mock interfaces and class with virtuals Mock properties that includes indexers Set raise event for specific calls Use matchers to control mock arguments Assert specific occurrence of a mocked calls. Assert using matchers Do recursive mocks Do Sequential mocking ( same method with argument returns different values or perform different tasks) Do strict mocking (by default and i prefer loose , so that i can use it as stubs) Elevated mode Mock static calls Mock final class Mock sealed classes Mock Extension methods Partially mock a  class member directly using Mock.Arrange Mock MsCorlib (we will support more and more members in coming days) , currently we support FileInfo, File and DateTime. These are few, you need to take a look at the test project that is provided with the build to find more [Along with the document]. Also, one of feature that will i will be using it for my next OS projects is the ability to run it separately in  proxied mode which makes it easy to redistribute and do some personal development in a more DI model and my option to elevate as it go.   I’ve surely forgotten tons of other features to mention that i will cover time but  don’t for get the URL : www.telerik.com/justmock   Finally a little mock code:   var lvMock = Mock.Create<ILoveJustMock>();    // set your goal  Mock.Arrange(() => lvMock.Response(Arg.Any<string>())).Returns((int result) => result);    //perform  string ret =  lvMock.Echo("Yes");    Assert.Equal(ret, "Yes");  // make sure everything is fine  Mock.Assert(() => lvMock.Echo("Yes"), Occurs.Once());   Hope that helps to get started,  will cover if not :-).

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• Vacations on Rodrigues 2014

  And now something completely different compared to the usual technical or community related articles here on this blog. Yes, this time I'm writing some lines on my (and my family's) activities during our long weekend stay on Rodrigues. So, please bear with me, it's eventually a bit more personal... Grab a soda, some popcorn and a cosy place to continue to read. var googleAlbumLink = "https://plus.google.com/photos/117698191428446859536/albums/6047895311458281985"; //optional----------------------- var mySlideWidth = 580; var mySlideHeight = 340; var mySlideDelay = 7000; //delay in milliseconds Special promotions during school holidays Originally, our children started to ask more frequently about going on the plane again. Obviously, after their aunty from Germany was around during May, they were really eager to travel again. So, we decided that it might be a great opportunity to book some vacations during their school holidays. And just in time the local hotels and hotel groups started to advertise their special promotions for citizens and residents. After collecting multiple brochures over several days, we got attracted by various hotel packages on Rodrigues - most interestingly the expenses for the stay and flight ticket were less compared to other resorts here on the main island. As we have been to Rodrigues already back in 2008, we followed up on this idea and got in touch with a couple travel agencies. Well, I have to report that you should be really careful about the promotions from some of them. We had a very negative experience with Shamal Travel Agency in Quatre Bornes regarding their adverts and the actual price levels and age definition for children. Please, stay away from them if you are interested in transparent cost and services. Anyway, after some arrangements with two other close families we managed to confirm our stay at the Cotton Bay Hotel in Rodrigues. Given the fact that we already stayed there, and the hotel has been renovated recently, and it is under new management all looked very promising and relaxed for our vacation. Counting the days... As we already booked in July our children were counting down the days. And it got more interesting as soon as they were on school holidays finally. Well, the day arrived and waking them up at 2:30 hrs wasn't a problem after all. Quite the opposite it was fascinating for us parents to watch them waiting for the transport and later on during the airport transfer. Despite the early hours both didn't fall asleep and it was all so exciting. We are taking the plane! Well organised by the Cotton Bay Hotel Honestly, it was a breeze and a smooth ride during our stay at the hotel. From the airport transfer, the cleanliness of our bungalow, the organisation of our day trips, and the SPA - all very well and enjoyable. The children had great fun, and although it was a bit too windy to plunge into the pool they had a lot of fun with other activities on the beach and at the Kid's Club. Oh, and we had our private petting zoo with cows, sheep and goats just close to the terrace. Some of us went to check out the SPA facilities and I have to admit that the services regarding Hammam and Sauna are better than at some other hotels in Mauritius. I don't know after how many months or years I was once again enjoying a very hot sauna. Little draw-back but nothing to worry about... There is no cold water or at least ice cubes to cool down the body, but hey there was a nice breeze coming over the hills. Some day trips to mention Based on a friend's recommendation we walked to a "restaurant" called Chez Solange & Robert. Hahaha, restaurant is widely stretched in this case, as we enjoyed a great BBQ with fresh lobster, whole fish, and pieces of chicken breast in an open cottage. Just some wooden structure covered with dried palm leaves on the roof - island feeling pure! The other day we went to the Giant Tortoise & Cave Reserve Francois Leguat to observe the giant Aldabra turtles and to visit the Grande Caverne. The biggest limestone cave on the island. Compared to our last visit this was a novelty after checking out the Caverne Partate. The formations of stalactites and stalagmites are very impressive and imaginative. Our guide had lots of funny terms and despite the low light conditions the kids had a great time wandering around on the narrow wooden paths and stairs. And last but not least, we decided to check out the Tyrodrig zip lines... Everyone was allowed to join the trip through the air, and our little ones stayed close to our field guides. But finally went on their own on the very last traversal. Puuuh, it was astounishing to glide over the valley, and for sure something to repeat next time. Impressions of our vacation on Rodrigues 2014   Next stay has been discussed already Oh yes, Rodrigues baby! We are going to come again! Tentative dates have been discussed already and now it's up to us to earn enough our next holiday on that wonderful remote piece of paradise. Eventually, a little bit longer than this time. We'll see...

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• Flash Actionscript 3.0 Game Projectile Creation

  - by Christian Basar

  I have been creating a side-scrolling Actionscript 3.0 game. In this game I want the Player to be able to shoot blow darts as weapons. I had some trouble getting the darts to be created in the right place (in front of the player), but eventually got it working with some help from this page (please look at it for background information on this problem): http://stackoverflow.com/questions/8031553/flash-actionscript-3-0-game-projectile-creation I got the darts to be created in the right place (near the player) and a 'movePlayerDarts()' function moves them. But I actually have a new problem. When the player moves after firing a dart, the dart tries to follow him! If the player jumps, the dart rises up. If the player moves to the left, the dart moves slightly to the left. Obviously, there is some code somewhere which is telling the darts to follow the player. I do not see how, unless the 'playerDartContainer' has something to do with that. But the container is always at position (0,0) and it does not move. Also, as a test I traced a dart's 'y' coordinate within the constantly-running 'movePlayerDarts()' function. As you can see, that function constantly moves the dart down the y axis by increasing its y-coordinate value. But when I jump, the 'y' coordinate being traced is never reduced, even though the dart clearly looks like it's rising! If anybody has any suggestions, I'd appreciate them! Here is the code I use to create the darts: // This function creates a dart public function createDart():void { if (playerDartContainer.numChildren <= 4) { // Play dart shooting sound sndDartShootIns.play(); // Create a new 'PlayerDart' object playerDart = new PlayerDart(); // Set the new dart's initial position and direction depending on the player's direction // Player's facing right if (player.scaleX == 1) { // Create dart in front of player's dart gun playerDart.x = player.x + 12; playerDart.y = player.y - 85; // Dart faces right, too playerDart.scaleX = 1; } // Player's facing left else if (player.scaleX == -1) { // Create dart in front of player's dart gun playerDart.x = player.x - 12; playerDart.y = player.y - 85; // Dart faces left, too playerDart.scaleX = -1; } playerDartContainer.addChild(playerDart); } } // End of 'createDart()' function This code is the EnterFrameHandler for the player darts: // In every frame, call 'movePlayerDarts()' to move the darts within the 'playerDartContainer' public function playerDartEnterFrameHandler(event:Event):void { // Only move the Player's darts if their container has at least one dart within if (playerDartContainer.numChildren > 0) { movePlayerDarts(); } } And finally, this is the code that actually moves all of the player's darts: // Move all of the Player's darts public function movePlayerDarts():void { for (var pdIns:int = 0; pdIns < playerDartContainer.numChildren; pdIns++) { // Set the Player Dart 'instance' variable to equal the current PlayerDart playerDartIns = PlayerDart(playerDartContainer.getChildAt(pdIns)); // Move the current dart in the direction it was shot. The dart's 'x-scale' // factor is multiplied by its speed (5) to move the dart in its correct // direction. If the 'x-scale' factor is -1, the dart is pointing left (as // seen in the 'createDart()' function. (-1 * 5 = -5), so the dart will go // to left at a rate of 5. The opposite is true for the right-ward facing // darts playerDartIns.x += playerDartIns.scaleX * 1; // Make gravity work on the dart playerDartIns.y += 0.7; //playerDartIns.y += 1; // What if the dart hits the ground? if (HitTest.intersects(playerDartIns, floor, this)) { playerDartContainer.removeChild(playerDartIns); } //trace("Dart x: " + playerDartIns.x); trace("Dart y: " + playerDartIns.y); } }

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• Problems with opening CHM Help files from Network or Internet

  - by Rick Strahl

  As a publisher of a Help Creation tool called Html Help Help Builder, I’ve seen a lot of problems with help files that won't properly display actual topic content and displays an error message for topics instead. Here’s the scenario: You go ahead and happily build your fancy, schmanzy Help File for your application and deploy it to your customer. Or alternately you've created a help file and you let your customers download them off the Internet directly or in a zip file. The customer downloads the file, opens the zip file and copies the help file contained in the zip file to disk. She then opens the help file and finds the following unfortunate result:     The help file  comes up with all topics in the tree on the left, but a Navigation to the WebPage was cancelled or Operation Aborted error in the Help Viewer's content window whenever you try to open a topic. The CHM file obviously opened since the topic list is there, but the Help Viewer refuses to display the content. Looks like a broken help file, right? But it's not - it's merely a Windows security 'feature' that tries to be overly helpful in protecting you. The reason this happens is because files downloaded off the Internet - including ZIP files and CHM files contained in those zip files - are marked as as coming from the Internet and so can potentially be malicious, so do not get browsing rights on the local machine – they can’t access local Web content, which is exactly what help topics are. If you look at the URL of a help topic you see something like this:   mk:@MSITStore:C:\wwapps\wwIPStuff\wwipstuff.chm::/indexpage.htm which points at a special Microsoft Url Moniker that in turn points the CHM file and a relative path within that HTML help file. Try pasting a URL like this into Internet Explorer and you'll see the help topic pop up in your browser (along with a warning most likely). Although the URL looks weird this still equates to a call to the local computer zone, the same as if you had navigated to a local file in IE which by default is not allowed.  Unfortunately, unlike Internet Explorer where you have the option of clicking a security toolbar, the CHM viewer simply refuses to load the page and you get an error page as shown above. How to Fix This - Unblock the Help File There's a workaround that lets you explicitly 'unblock' a CHM help file. To do this: Open Windows Explorer Find your CHM file Right click and select Properties Click the Unblock button on the General tab Here's what the dialog looks like:   Clicking the Unblock button basically, tells Windows that you approve this Help File and allows topics to be viewed.   Is this insecure? Not unless you're running a really old Version of Windows (XP pre-SP1). In recent versions of Windows Internet Explorer pops up various security dialogs or fires script errors when potentially malicious operations are accessed (like loading Active Controls), so it's relatively safe to run local content in the CHM viewer. Since most help files don't contain script or only load script that runs pure JavaScript access web resources this works fine without issues. How to avoid this Problem As an application developer there's a simple solution around this problem: Always install your Help Files with an Installer. The above security warning pop up because Windows can't validate the source of the CHM file. However, if the help file is installed as part of an installation the installation and all files associated with that installation including the help file are trusted. A fully installed Help File of an application works just fine because it is trusted by Windows. Summary It's annoying as all hell that this sort of obtrusive marking is necessary, but it's admittedly a necessary evil because of Microsoft's use of the insecure Internet Explorer engine that drives the CHM Html Engine's topic viewer. Because help files are viewing local content and script is allowed to execute in CHM files there's potential for malicious code hiding in CHM files and the above precautions are supposed to avoid any issues. © Rick Strahl, West Wind Technologies, 2005-2012 Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Threading Overview

  - by ACShorten

  One of the major features of the batch framework is the ability to support multi-threading. The multi-threading support allows a site to increase throughput on an individual batch job by splitting the total workload across multiple individual threads. This means each thread has fine level control over a segment of the total data volume at any time. The idea behind the threading is based upon the notion that "many hands make light work". Each thread takes a segment of data in parallel and operates on that smaller set. The object identifier allocation algorithm built into the product randomly assigns keys to help ensure an even distribution of the numbers of records across the threads and to minimize resource and lock contention. The best way to visualize the concept of threading is to use a "pie" analogy. Imagine the total workset for a batch job is a "pie". If you split that pie into equal sized segments, each segment would represent an individual thread. The concept of threading has advantages and disadvantages: Smaller elapsed runtimes - Jobs that are multi-threaded finish earlier than jobs that are single threaded. With smaller amounts of work to do, jobs with threading will finish earlier. Note: The elapsed runtime of the threads is rarely proportional to the number of threads executed. Even though contention is minimized, some contention does exist for resources which can adversely affect runtime. Threads can be managed individually – Each thread can be started individually and can also be restarted individually in case of failure. If you need to rerun thread X then that is the only thread that needs to be resubmitted. Threading can be somewhat dynamic – The number of threads that are run on any instance can be varied as the thread number and thread limit are parameters passed to the job at runtime. They can also be configured using the configuration files outlined in this document and the relevant manuals.Note: Threading is not dynamic after the job has been submitted Failure risk due to data issues with threading is reduced – As mentioned earlier individual threads can be restarted in case of failure. This limits the risk to the total job if there is a data issue with a particular thread or a group of threads. Number of threads is not infinite – As with any resource there is a theoretical limit. While the thread limit can be up to 1000 threads, the number of threads you can physically execute will be limited by the CPU and IO resources available to the job at execution time. Theoretically with the objects identifiers evenly spread across the threads the elapsed runtime for the threads should all be the same. In other words, when executing in multiple threads theoretically all the threads should finish at the same time. Whilst this is possible, it is also possible that individual threads may take longer than other threads for the following reasons: Workloads within the threads are not always the same - Whilst each thread is operating on the roughly the same amounts of objects, the amount of processing for each object is not always the same. For example, an account may have a more complex rate which requires more processing or a meter has a complex amount of configuration to process. If a thread has a higher proportion of objects with complex processing it will take longer than a thread with simple processing. The amount of processing is dependent on the configuration of the individual data for the job. Data may be skewed – Even though the object identifier generation algorithm attempts to spread the object identifiers across threads there are some jobs that use additional factors to select records for processing. If any of those factors exhibit any data skew then certain threads may finish later. For example, if more accounts are allocated to a particular part of a schedule then threads in that schedule may finish later than other threads executed. Threading is important to the success of individual jobs. For more guidelines and techniques for optimizing threading refer to Multi-Threading Guidelines in the Batch Best Practices for Oracle Utilities Application Framework based products (Doc Id: 836362.1) whitepaper available from My Oracle Support

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