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  • Is there an alias for the local machine name in the Windows 7 login screen?

    - by Mikael
    We have many computers connected to a AD. The computers names is auto generated. When I want to log in using a local account, I have to figure out what the computer's name is, and log in using the following syntax: [COMPUTER_NAME]\local_account Now I'm wondering if there is an alias that I can use instead? So instead of logging in using NB-aw35sdds\local_account, I can use something like localhost\local_account.

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  • How come the Name property is <Unknown> on a FileStream which uses handle constructors?

    - by Mikael Svenson
    Say you get a file handle from some outside DLL and instantiate a FileStream with it. It works just fine for reading and writing. Then you want the path and name of that handle and try to access the Name property of your FileStream object, and it returns 'unknown'. This is true for the constructors which takes file handles: public FileStream(IntPtr handle, ... public FileStream(SafeFileHandle handle, ... I know the short answer, because it's not implemented. The private field _fileName of FileStream is never assigned in those constructors. Seems the API to get the name from a handle involves more than one line of code, but I still think they could have bothered to include this. So the real questions is: Why haven't they? Or did they just forget?

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  • Error after updating to the latest version Azure SDK

    - by Mikael Johansson
    After I updated to the newest version the Azure SDK I have started to get this error several times each day when I press build in Visual Studio. The only way for me to fix it at the moment is to restart my visual studio. The error I get is: Windows Azure Tools: Invalid access to memory location Is there someone else that have got this error? And also what did you do to fix it? Thanks in advance! Update 2012-08-28: The same error still exist in VS2012 and Azure 1.7 SDK. However the frequency have gone down with VS2012.

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  • Prepopulate jQuery Data in html

    - by Mikael
    jQuery has the very cool feature/method ".data", i wonder if there is a way to have the data in the code so that jQuery can use it when the rendering of html is done. Suppose i have a repeater and looping out children, and i want to add some data to those children without using classes etc. Will i have to add javascript to that repeater just to add stuff to the "data of jquery" or is there some better way?

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  • Creating a new object destroys an older object with different name in C++

    - by Mikael
    First question here! So, I am having some problems with pointers in Visual C++ 2008. I'm writing a program which will control six cameras and do some processing on them so to clean things up I have created a Camera Manager class. This class handles all operations which will be carried out on all the cameras. Below this is a Camera class which interacts with each individual camera driver and does some basic image processing. Now, the idea is that when the manager is initialised it creates two cameras and adds them to a vector so that I can access them later. The catch here is that when I create the second camera (camera2) the first camera's destructor is called for some reason, which then disconnects the camera. Normally I'd assume that the problem is somewhere in the Camera class, but in this case everything works perfectly as long as I don't create the camera2 object. What's gone wrong? CameraManager.h: #include "stdafx.h" #include <vector> #include "Camera.h" class CameraManager{ std::vector<Camera> cameras; public: CameraManager(); ~CameraManager(); void CaptureAll(); void ShowAll(); }; CameraManager.cpp: #include "stdafx.h" #include "CameraManager.h" CameraManager::CameraManager() { printf("Camera Manager: Initializing\n"); [...] Camera *camera1 = new Camera(NodeInfo,1, -44,0,0); cameras.push_back(*camera1); // Adding the following two lines causes camera1's destructor to be called. Why? Camera *camera2 = new Camera(NodeInfo,0, 44,0,0); cameras.push_back(*camera2); printf("Camera Manager: Ready\n"); }

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  • Which way is preferred when doing asynchronous WCF calls?

    - by Mikael Svenson
    When invoking a WCF service asynchronous there seems to be two ways it can be done. 1. public void One() { WcfClient client = new WcfClient(); client.BegindoSearch("input", ResultOne, null); } private void ResultOne(IAsyncResult ar) { WcfClient client = new WcfClient(); string data = client.EnddoSearch(ar); } 2. public void Two() { WcfClient client = new WcfClient(); client.doSearchCompleted += TwoCompleted; client.doSearchAsync("input"); } void TwoCompleted(object sender, doSearchCompletedEventArgs e) { string data = e.Result; } And with the new Task<T> class we have an easy third way by wrapping the synchronous operation in a task. 3. public void Three() { WcfClient client = new WcfClient(); var task = Task<string>.Factory.StartNew(() => client.doSearch("input")); string data = task.Result; } They all give you the ability to execute other code while you wait for the result, but I think Task<T> gives better control on what you execute before or after the result is retrieved. Are there any advantages or disadvantages to using one over the other? Or scenarios where one way of doing it is more preferable?

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  • Visual C++ function suddenly 170 ms slower (4x longer)

    - by Mikael
    For the past few months I've been working on a Visual C++ project to take images from cameras and process them. Up until today this has taken about 65 ms to update the data but now it has suddenly increased significantly. What happens is: I launch my program and for the first 30 or so iterations it performs as expected, then suddenly the loop time increases from 65 ms to 250 ms. The odd thing is, after timing each function I found out that the part of the code which is causing the slowdown is fairly basic and has not been modified in over a month. The data which goes into it is unchanged and identical every iteration but the execution time which is initially less than 1 ms suddenly increases to 170 ms while the rest of the code is still performing as expected (time-wise). Basically, I am calling the same function over and over, for the first 30 calls it performs as it should, after that it slows down for no apparent reason. It might also be worth noting that it is a sudden change in execution time, not a gradual increase. What could be causing this? The code is leaking some memory (~50 kb/s) but not nearly enough to warrant a sudden 4x slowdown. If anyone has any ideas I'd love to hear them!

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  • Visual C++ function suddenly 170x slower

    - by Mikael
    For the past few months I've been working on a Visual C++ project to take images from cameras and process them. Up until today this has taken about 65 ms to update the data but now it has suddenly increased significantly. What happens is: I launch my program and for the first 30 or so iterations it performs as expected, then suddenly the loop time increases from 65 ms to 250 ms. The odd thing is, after timing each function I found out that the part of the code which is causing the slowdown is fairly basic and has not been modified in over a month. The data which goes into it is unchanged and identical every iteration but the execution time which is initially less than 1 ms suddenly increases to 170 ms while the rest of the code is still performing as expected (time-wise). Basically, I am calling the same function over and over, for the first 30 calls it performs as it should, after that it slows down for no apparent reason. It might also be worth noting that it is a sudden change in execution time, not a gradual increase. What could be causing this? The code is leaking some memory (~50 kb/s) but not nearly enough to warrant a sudden 4x slowdown. If anyone has any ideas I'd love to hear them!

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  • Pass 2-dimensional array trough view

    - by Mikael
    Hi, I'm trying to print a 2-dimensional array but can't figure it out. My controller uses this code: public ActionResult Test(string str) { DateTimeOffset offset = new DateTimeOffset(DateTime.Now); offset = offset.AddHours(-5); string[,] weekDays = new string[7,2]; for (int i = 0; i < 7; i++) { weekDays[i,0] = String.Format("{0:yyyy-MM-dd:dddd}", offset); //Date weekDays[i,1] = String.Format("{0:dddd}", offset); //Text offset = offset.AddHours(24); } weekDays[0,1] = "Today"; ViewData["weekDays"] = weekDays; return View(); } Now I wan't to print this array of weekdays as a dropdown-list and i thought this would work: <% foreach (var item in (string[,])ViewData["weekDays"]) { %> <option value=" <%= item[0] %> "> <%= item[1] %> </option> <% } %> But that's not the case, this code output just the first char of the string. So anyone got a suggestion? Thanks! /M

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  • XML in Authorware 7.01

    - by Mikael
    Let me explain the setup that is being used. Right now I have an authorware program which loads an ocx control. This control receives data in the form on an XML string. This part is working properly. However I need parse this XML string in authorware and have not been successful. I have been trying to use the XMLParser Xtra. The documentation listed here shows how to create a new XMLParser object and then shows how to call the object but never explains how to link the Parser to a XML file or XML string. The information I have been using can be found here https://www.adobe.com/livedocs/authorware/7/using_aw_en/wwhelp/wwhimpl/common/html/wwhelp.htm?context=Using_Authorware_7&file=09_va110.htm#224295 I need more information on how to Parse XML with this function or if there is another way to do this in Authorware. As a side note the documentation says it cannot create or append to XML, I will need to do this also inside of Authorware. Is this possible and if so, how?

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  • How get current month short name with jquery ui datepicker instead full month name?

    - by Yosef
    My code that give long month name instead short name: var monthShortName=$.datepicker.formatDate('MM d, yy', new Date(),{ monthNamesShort: ['Jan','Feb','Mar','Apr','Maj','Jun','Jul','Aug','Sep','Okt','Nov','Dec'] }); alert(monthShortNam); // "March" and not like i want "Mar" Thanks (I use JQuery 1.7.1 + jQuery UI 1.8.2) Edit - Eliasson Solution('M' and not 'MM'): $.datepicker.formatDate('M d, yy', new Date());

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  • Setting up Splunk/IronPort WSA

    - by Ciddan
    Hello everyone! I recently stumbled across Splunk 4 (by way of an advert on this very site...) and found that it had an "App" that's designed to work with Cisco IronPort WebSecurity and E-Mail Appliances! That's really awesome, because good IronPort reporting is something our IT-dept. is looking for. Anyways - I'm totally lost on how to configure this thing. I've googled like a mad-man to find a guide or such like - but I haven't found anything. Has anyone here set up IP / Splunk? Any tips/pointers? Regards, Mikael Selander

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  • Code Contracts and Pex at MSDN Live 2010

    - by terje
    One of the 6 sessions I and Mikael Nitell is running on MSDN Live 2010 here in Norway is about Code Quality, and part of that session goes through the use of Code Contracts and Pex.  Both fantastic tools ! They can be used togethers, but are also completely independent from each other, and can be used as a single Code Contracts  has to downloaded separately from VS 2010 (works also on VS 2008).   Start looking at http://msdn.microsoft.com/en-us/devlabs/dd491992.aspx . This download is a free download.   Code Contracts originates form the ideas of Bertrand Meyer – Design by Contract, take a look here. Pex is found on the MSDN Subscription download, so it requires an active MSDN Subscription. Start to get it from here http://research.microsoft.com/en-us/projects/pex/downloads.aspx .  The current version as of 14.4.10 is 0.9, which works with the 2010 RC.  A new version is due this week.  Pex is a tool to generate unit tests, and does this very intelligently.  Perfect to make tests for legacy code, but also to make sure you get all paths tested.  See the Reference information and project startup information.

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  • Iphone/Android app – chatroom development – what framework & hosting needs?

    - by MikaelW
    I have some experience regarding IPhone and Android development but I am now struggling to solve a new class of problem: apps that involve a client/server chatroom feature. That is, an app when people can exchange text over the internet, and without having the app to constantly “pull” content from the server. So that problem can’t be solved with a normal php/mysql website, there must be some kind of application running on a server that is able to send message from the server to the phone, rather than having the phone to check for new messages every 10 seconds… So I’m looking for ways to solve the different problems here: What framework should I use on the two sides (phone / server)? It should be some kind of library that doesn’t prevent me to write paid apps. It should also be possible to have the same server for the Iphone and android version of the app. What server / hosting solution do I need with what sort of features, I just have no experience regarding server application that can handle and initiate multiple connections and are hosted on hardware that is always online I tried to find resources online but couldn’t so far, either the libraries had the wrong kind of license/language or I just didn’t understand… Sometimes there were nice tutorial but for different needs such as peer2peer chat over local network… Same with the server and the hosting problem, not sure where to start really, I’m calling for help and I promise I will complete this page with notes about the experience I will get :-) Obviously the ideal would be to find a tutorial I missed that include client code, server code and a free scalable server… That being said, If I see something as good, it probably means that I have eaten the wrong kind of mushroom again… So, failing that, any pointer which might help me toward that quest, would be greatly appreciated. Thanks in advance. Mikael

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  • Iphone/Android app – chatroom development – what framework & hosting needs?

    - by MikaelW
    I have some experience regarding IPhone and Android development but I am now struggling to solve a new class of problem: apps that involve a client/server chatroom feature. That is, an app when people can exchange text over the internet, and without having the app to constantly “pull” content from the server. So that problem can’t be solved with a normal php/mysql website, there must be some kind of application running on a server that is able to send message from the server to the phone, rather than having the phone to check for new messages every 10 seconds… So I’m looking for ways to solve the different problems here: What framework should I use on the two sides (phone / server)? It should be some kind of library that doesn’t prevent me to write paid apps. It should also be possible to have the same server for the Iphone and android version of the app. What server / hosting solution do I need with what sort of features, I just have no experience regarding server application that can handle and initiate multiple connections and are hosted on hardware that is always online I tried to find resources online but couldn’t so far, either the libraries had the wrong kind of license/language or I just didn’t understand… Sometimes there were nice tutorial but for different needs such as peer2peer chat over local network… Same with the server and the hosting problem, not sure where to start really, I’m calling for help and I promise I will complete this page with notes about the experience I will get :-) Obviously the ideal would be to find a tutorial I missed that include client code, server code and a free scalable server… That being said, If I see something as good, it probably means that I have eaten the wrong kind of mushroom again… So, failing that, any pointer which might help me toward that quest, would be greatly appreciated. Thanks in advance. Mikael

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  • MSDN Live 2010 &ndash; Delivered : 24 sessions (4 x 6) on Visual Studio and Team Foundation Server

    - by terje
    We (Mikael Nitell and me) got a whole track on the Norwegian MSDN Live tour this year.  We did these as a pair, and covered 4 cities over 4 days, 6 sessions per day, taking 8 hours to come through it.  The Islandic volcano made the travels a bit rough, but we managed 6 flights out of 8. The first one had to go by van instead, 7-8 hour drive each way together with other MSDN Live presenters – a memorable tour! Oslo was the absolute top point.  We had to change hall to a bigger one. People were crowding, and even the big hall was packed!  The presentations were mostly based on demos, but we had a few slides as well.  They have been uploaded to my SkyDrive.  Info to aliens – some of the text may be Norwegian. The sessions were as follows: Overview of news in Visual Studio and Team Foundation server 2010 Ensuring Quality with VS/TFS 2010 Releasing products with VS/TFS 2010 No More No Repro with VS/TFS 2010 Performance Testing and Parallel Programming with VS/TFS 2010 Migrating to VS/TFS 2010 Tips, tricks, news and some best practices with VS/TFS 2010   In the coming days, I will post up examples from the demos too, with explanations of how they are intended to work. These entries will also contain stuff we had to remove from the actual presentations due to the time constraints. We managed to create recordings of two of the sessions, which will be uploaded to Channel 9 by Microsoft, afaik.   I will update this blog with information about exact locations when that is done. Also note we’re (read:Osiris Data AS) running both Upgrade and Deep Dive courses  on VS/TFS 2010 now in May.  Please look here for more info. If you want to be informed, follow me on Twitter.  All blog entries will be announced on twitter.

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  • Podcast Show Notes: The Fusion Middleware A-Team and the Chronicles of Architecture

    - by Bob Rhubart
    If you pay any attention at all to the Oracle blogosphere you’ve probably seen one of several blogs published by members of a group known as the Oracle Fusion Middleware A-Team. A new blog, The Oracle A-Team Chronicles, was recently launched that combines all of those separate A-Team blogs in one. In this program you’ll meet some of the people behind the A-team and the creation of that new blog. The Conversation Listen to Part 1: Background on the A-Team - When was it formed? What is it’s mission? 54) What are some of the most common challenges A-Team architects encounter in the field? Listen to Part 2 (July 3): The panel discusses the trends - big data, mobile, social, etc - that are having the biggest impact in the field. Listen to Part 3 (July 10): The panelists discuss the analysts, journalists, and other resources they rely on to stay ahead of the curve as the technology evolves, and reveal the last article or blog post they shared with other A-team members. The Panelists Jennifer Briscoe: Senior Director, Oracle Fusion Middleware A-Team Clifford Musante: Lead Architect, Application Integration Architecture A-Team, webmaster of the A-Team Chronicles Mikael Ottosson: Vice President, Oracle Fusion Apps and Fusion Middleware A-Team and Cloud Applications Group Pardha Reddy: Senior director of Oracle Identity Management and a member of the Oracle Fusion Middleware A-team Coming Soon Data Warehousing and Oracle Data Integrator: Guest producer and Oracle ACE Director Gurcan Orhan selected the topic and panelists for this program, which also features Uli Bethke, Michael Rainey, and Oracle ACE Cameron Lackpour. Java and Oracle ADF Mobile: An impromptu roundtable discussion featuring QCon New York 2013 session speakers Doug Clarke, Frederic Desbiens, Stephen Chin, and Reza Rahman. Stay tuned:

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  • Mobile development, recommended computer configuration?

    - by MikaelW
    Hi, For the last 4 weeks, I have been trying to get into mobile development. Done a couple of tutorials, read some books, developed a couple of dummy Android apps. The thing is my computer is a 5 years old laptop, it is slow and time has come to replace it and I’m looking at different offers online. Have you got any recommendations? Is there any must-have that should make my developer life easier in the future? Is there anything specific that may be useful at a more advanced stage of development that I just can’t think of right now on the hardware side? (I mean apart from good proc, lots of RAM, many USB ports...) One thing I can think of is to have three OS on the same workstation: Windows, Unix and MacOS (so far I focused on android/java/eclipse but am interested in Iphone/objC/xcode as well) but that’s more on the software side. Anyway, would be grateful for any recommendations. Thanks in advance! Mikael PS: I’m quite free on the budget side of things PPS: I'm aware it's not really a programming question but will still be of interest to some programmers here.

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  • Archbeat Link-O-Rama Top 10 Facebook Faves - June 23-29, 2013

    - by Bob Rhubart
    2,947 people now follow OTN ArchBeat on Facebook. Here are the Top 10 items shared on that page for June 23-29, 2013. Podcast Show Notes: DevOps, Cloud, and Role Creep After some confusion (my bad) all three CORRECT parts of this podcast are now available. The panelists for this discussion are all Oracle ACE Directors: Ron Batra, Basheer Khan, and Cary Millsap. SOA Suite 11g Developers Cookbook Published | Antony Reynolds "The book focuses on areas that we felt we had neglected in the Developers Guide, says co-author Antony Reynolds. "There is more about Java integration and OSB, both of which we see a lot of questions about when working with customers." Using Oracle TimesTen With Oracle BI Applications (Part 2) | Peter Scott Peter Scott follows up an earlier post with a look at some of the OBIA structures and a discussion of some of the features of TimesTen. Linux-Containers — Part 1: Overview | Lenz Grimmer OTN Garage blogger Lenz Grimmer kicks off a series and expands your mind with deep detail on Linux Containers Slides from my ODTUG Kscope13 Presentation | Zeeshan Baig Oracle ACE Zeeshan Baig shares the slides from his KScope13 presentation, "Build Your Business Services Using ADF Task Flows." Fun with Enterprise Manager | Rene van Wijk Oracle ACE Rene van Wijk shares some background and some tuning and other tech tips for working with Oracle Enterprise Manager. Using VirtualBox to test drive Windows Blue | The Fat Bloke The Fat Bloke shares a tech tip for those interested in giving Windows Blue a try on Virtual Box. Podcast Show Notes: The Fusion Middleware A-Team and the Chronicles of Architecture In this three-part series Oracle Fusion Middleware A-Team members Jennifer Briscoe, Clifford Musante, Mikael Ottosson, and Pardha Reddy talk about the origins and mission of the FMW A-Team and about the great technical content you'll find on the recently launched Oracle A-Team blog. Part one is now available. 5 Best Practices - Laying the Foundation for WebCenter Projects | John Brunswick Oracle WebCenter expert John Brunswick shares best practices that "enable the creation of portal solutions with minimal resource overhead, while offering the greatest flexibility for progressive elaboration." Oracle Magazine - July/Aug 2013 The digital edition of the July/August edition of Oracle Magazine is now available. This issue includes my architect community column, "The CX Factor." which features insight from community members on "why and how CX has become a significant factor in enterprise IT." h

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  • What is the equivalent of memset in C#?

    - by Jedidja
    I need to fill a byte[] with a single non-zero value. How can I do this in C# without looping through each byte in the array? Update: The comments seem to have split this into two questions - Is there a Framework method to fill a byte[] that might be akin to memset What is the most efficient way to do it when we are dealing with a very large array? I totally agree that using a simple loop works just fine, as Eric and others have pointed out. The point of the question was to see if I could learn something new about C# :) I think Juliet's method for a Parallel operation should be even faster than a simple loop. Benchmarks: Thanks to Mikael Svenson: http://techmikael.blogspot.com/2009/12/filling-array-with-default-value.html It turns out the simple for loop is the way to go unless you want to use unsafe code. Apologies for not being clearer in my original post. Eric and Mark are both correct in their comments; need to have more focused questions for sure. Thanks for everyone's suggestions and responses.

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  • Configuring MySQL Cluster Data Nodes

    - by Mat Keep
    0 0 1 692 3948 Homework 32 9 4631 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} In my previous blog post, I discussed the enhanced performance and scalability delivered by extensions to the multi-threaded data nodes in MySQL Cluster 7.2. In this post, I’ll share best practices on the configuration of data nodes to achieve optimum performance on the latest generations of multi-core, multi-thread CPU designs. Configuring the Data Nodes The configuration of data node threads can be managed in two ways via the config.ini file: - Simply set MaxNoOfExecutionThreads to the appropriate number of threads to be run in the data node, based on the number of threads presented by the processors used in the host or VM. - Use the new ThreadConfig variable that enables users to configure both the number of each thread type to use and also which CPUs to bind them too. The flexible configuration afforded by the multi-threaded data node enhancements means that it is possible to optimise data nodes to use anything from a single CPU/thread up to a 48 CPU/thread server. Co-locating the MySQL Server with a single data node can fully utilize servers with 64 – 80 CPU/threads. It is also possible to co-locate multiple data nodes per server, but this is now only required for very large servers with 4+ CPU sockets dense multi-core processors. 24 Threads and Beyond! An example of how to make best use of a 24 CPU/thread server box is to configure the following: - 8 ldm threads - 4 tc threads - 3 recv threads - 3 send threads - 1 rep thread for asynchronous replication. Each of those threads should be bound to a CPU. It is possible to bind the main thread (schema management domain) and the IO threads to the same CPU in most installations. In the configuration above, we have bound threads to 20 different CPUs. We should also protect these 20 CPUs from interrupts by using the IRQBALANCE_BANNED_CPUS configuration variable in /etc/sysconfig/irqbalance and setting it to 0x0FFFFF. The reason for doing this is that MySQL Cluster generates a lot of interrupt and OS kernel processing, and so it is recommended to separate activity across CPUs to ensure conflicts with the MySQL Cluster threads are eliminated. When booting a Linux kernel it is also possible to provide an option isolcpus=0-19 in grub.conf. The result is that the Linux scheduler won't use these CPUs for any task. Only by using CPU affinity syscalls can a process be made to run on those CPUs. By using this approach, together with binding MySQL Cluster threads to specific CPUs and banning CPUs IRQ processing on these tasks, a very stable performance environment is created for a MySQL Cluster data node. On a 32 CPU/Thread server: - Increase the number of ldm threads to 12 - Increase tc threads to 6 - Provide 2 more CPUs for the OS and interrupts. - The number of send and receive threads should, in most cases, still be sufficient. On a 40 CPU/Thread server, increase ldm threads to 16, tc threads to 8 and increment send and receive threads to 4. On a 48 CPU/Thread server it is possible to optimize further by using: - 12 tc threads - 2 more CPUs for the OS and interrupts - Avoid using IO threads and main thread on same CPU - Add 1 more receive thread. Summary As both this and the previous post seek to demonstrate, the multi-threaded data node extensions not only serve to increase performance of MySQL Cluster, they also enable users to achieve significantly improved levels of utilization from current and future generations of massively multi-core, multi-thread processor designs. A big thanks to Mikael Ronstrom, Senior MySQL Architect at Oracle, for his work in developing these enhancements and best practices. You can download MySQL Cluster 7.2 today and try out all of these enhancements. The Getting Started guides are an invaluable aid to quickly building a Proof of Concept Don’t forget to check out the MySQL Cluster 7.2 New Features whitepaper to discover everything that is new in the latest GA release

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  • Guide to MySQL & NoSQL, Webinar Q&A

    - by Mat Keep
    0 0 1 959 5469 Homework 45 12 6416 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} Yesterday we ran a webinar discussing the demands of next generation web services and how blending the best of relational and NoSQL technologies enables developers and architects to deliver the agility, performance and availability needed to be successful. Attendees posted a number of great questions to the MySQL developers, serving to provide additional insights into areas like auto-sharding and cross-shard JOINs, replication, performance, client libraries, etc. So I thought it would be useful to post those below, for the benefit of those unable to attend the webinar. Before getting to the Q&A, there are a couple of other resources that maybe useful to those looking at NoSQL capabilities within MySQL: - On-Demand webinar (coming soon!) - Slides used during the webinar - Guide to MySQL and NoSQL whitepaper  - MySQL Cluster demo, including NoSQL interfaces, auto-sharing, high availability, etc.  So here is the Q&A from the event  Q. Where does MySQL Cluster fit in to the CAP theorem? A. MySQL Cluster is flexible. A single Cluster will prefer consistency over availability in the presence of network partitions. A pair of Clusters can be configured to prefer availability over consistency. A full explanation can be found on the MySQL Cluster & CAP Theorem blog post.  Q. Can you configure the number of replicas? (the slide used a replication factor of 1) Yes. A cluster is configured by an .ini file. The option NoOfReplicas sets the number of originals and replicas: 1 = no data redundancy, 2 = one copy etc. Usually there's no benefit in setting it >2. Q. Interestingly most (if not all) of the NoSQL databases recommend having 3 copies of data (the replication factor).    Yes, with configurable quorum based Reads and writes. MySQL Cluster does not need a quorum of replicas online to provide service. Systems that require a quorum need > 2 replicas to be able to tolerate a single failure. Additionally, many NoSQL systems take liberal inspiration from the original GFS paper which described a 3 replica configuration. MySQL Cluster avoids the need for a quorum by using a lightweight arbitrator. You can configure more than 2 replicas, but this is a tradeoff between incrementally improved availability, and linearly increased cost. Q. Can you have cross node group JOINS? Wouldn't that run into the risk of flooding the network? MySQL Cluster 7.2 supports cross nodegroup joins. A full cross-join can require a large amount of data transfer, which may bottleneck on network bandwidth. However, for more selective joins, typically seen with OLTP and light analytic applications, cross node-group joins give a great performance boost and network bandwidth saving over having the MySQL Server perform the join. Q. Are the details of the benchmark available anywhere? According to my calculations it results in approx. 350k ops/sec per processor which is the largest number I've seen lately The details are linked from Mikael Ronstrom's blog The benchmark uses a benchmarking tool we call flexAsynch which runs parallel asynchronous transactions. It involved 100 byte reads, of 25 columns each. Regarding the per-processor ops/s, MySQL Cluster is particularly efficient in terms of throughput/node. It uses lock-free minimal copy message passing internally, and maximizes ID cache reuse. Note also that these are in-memory tables, there is no need to read anything from disk. Q. Is access control (like table) planned to be supported for NoSQL access mode? Currently we have not seen much need for full SQL-like access control (which has always been overkill for web apps and telco apps). So we have no plans, though especially with memcached it is certainly possible to turn-on connection-level access control. But specifically table level controls are not planned. Q. How is the performance of memcached APi with MySQL against memcached+MySQL or any other Object Cache like Ecache with MySQL DB? With the memcache API we generally see a memcached response in less than 1 ms. and a small cluster with one memcached server can handle tens of thousands of operations per second. Q. Can .NET can access MemcachedAPI? Yes, just use a .Net memcache client such as the enyim or BeIT memcache libraries. Q. Is the row level locking applicable when you update a column through memcached API? An update that comes through memcached uses a row lock and then releases it immediately. Memcached operations like "INCREMENT" are actually pushed down to the data nodes. In most cases the locks are not even held long enough for a network round trip. Q. Has anyone published an example using something like PHP? I am assuming that you just use the PHP memcached extension to hook into the memcached API. Is that correct? Not that I'm aware of but absolutely you can use it with php or any of the other drivers Q. For beginner we need more examples. Take a look here for a fully worked example Q. Can I access MySQL using Cobol (Open Cobol) or C and if so where can I find the coding libraries etc? A. There is a cobol implementation that works well with MySQL, but I do not think it is Open Cobol. Also there is a MySQL C client library that is a standard part of every mysql distribution Q. Is there a place to go to find help when testing and/implementing the NoSQL access? If using Cluster then you can use the [email protected] alias or post on the MySQL Cluster forum Q. Are there any white papers on this?  Yes - there is more detail in the MySQL Guide to NoSQL whitepaper If you have further questions, please don’t hesitate to use the comments below!

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