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• Parallelism in .NET – Introduction

  - by Reed

  Parallel programming is something that every professional developer should understand, but is rarely discussed or taught in detail in a formal manner.  Software users are no longer content with applications that lock up the user interface regularly, or take large amounts of time to process data unnecessarily.  Modern development requires the use of parallelism.  There is no longer any excuses for us as developers. Learning to write parallel software is challenging.  It requires more than reading that one chapter on parallelism in our programming language book of choice… Today’s systems are no longer getting faster with each generation; in many cases, newer computers are actually slower than previous generation systems.  Modern hardware is shifting towards conservation of power, with processing scalability coming from having multiple computer cores, not faster and faster CPUs.  Our CPU frequencies no longer double on a regular basis, but Moore’s Law is still holding strong.  Now, however, instead of scaling transistors in order to make processors faster, hardware manufacturers are scaling the transistors in order to add more discrete hardware processing threads to the system. This changes how we should think about software.  In order to take advantage of modern systems, we need to redesign and rewrite our algorithms to work in parallel.  As with any design domain, it helps tremendously to have a common language, as well as a common set of patterns and tools. For .NET developers, this is an exciting time for parallel programming.  Version 4 of the .NET Framework is adding the Task Parallel Library.  This has been back-ported to .NET 3.5sp1 as part of the Reactive Extensions for .NET, and is available for use today in both .NET 3.5 and .NET 4.0 beta. In order to fully utilize the Task Parallel Library and parallelism, both in .NET 4 and previous versions, we need to understand the proper terminology.  For this series, I will provide an introduction to some of the basic concepts in parallelism, and relate them to the tools available in .NET.

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• SQL Server and Hyper-V Dynamic Memory Part 2

  - by SQLOS Team

  Part 1 of this series was an introduction and overview of Hyper-V Dynamic Memory. This part looks at SQL Server memory management and how the SQL engine responds to changing OS memory conditions.   Part 2: SQL Server Memory Management As with any Windows process, sqlserver.exe has a virtual address space (VAS) of 4GB on 32-bit and 8TB in 64-bit editions. Pages in its VAS are mapped to pages in physical memory when the memory is committed and referenced for the first time. The collection of VAS pages that have been recently referenced is known as the Working Set. How and when SQL Server allocates virtual memory and grows its working set depends on the memory model it uses. SQL Server supports three basic memory models:   1. Conventional Memory Model   The Conventional model is the default SQL Server memory model and has the following properties: - Dynamic - can grow or shrink its working set in response to load and external (operating system) memory conditions. - OS uses 4K pages – (not to be confused with SQL Server “pages” which are 8K regions of committed memory).- Pageable - Can be paged out to disk by the operating system.   2. Locked Page Model The locked page memory model is set when SQL Server is started with "Lock Pages in Memory" privilege*. It has the following characteristics: - Dynamic - can grow or shrink its working set in the same way as the Conventional model.- OS uses 4K pages - Non-Pageable – When memory is committed it is locked in memory, meaning that it will remain backed by physical memory and will not be paged out by the operating system. A common misconception is to interpret "locked" as non-dynamic. A SQL Server instance using the locked page memory model will grow and shrink (allocate memory and release memory) in response to changing workload and OS memory conditions in the same way as it does with the conventional model.   This is an important consideration when we look at Hyper-V Dynamic Memory – “locked” memory works perfectly well with “dynamic” memory.   * Note in “Denali” (Standard Edition and above), and in SQL 2008 R2 64-bit (Enterprise and above editions) the Lock Pages in Memory privilege is all that is required to set this model. In 2008 R2 64-Bit standard edition it also requires trace flag 845 to be set, in 2008 R2 32-bit editions it requires sp_configure 'awe enabled' 1.   3. Large Page Model The Large page model is set using trace flag 834 and potentially offers a small performance boost for systems that are configured with large pages. It is characterized by: - Static - memory is allocated at startup and does not change. - OS uses large (>2MB) pages - Non-Pageable The large page model is supported with Hyper-V Dynamic Memory (and Hyper-V also supports large pages), but you get no benefit from using Dynamic Memory with this model since SQL Server memory does not grow or shrink. The rest of this article will focus on the locked and conventional SQL Server memory models.   When does SQL Server grow? For “dynamic” configurations (Conventional and Locked memory models), the sqlservr.exe process grows – allocates and commits memory from the OS – in response to a workload. As much memory is allocated as is required to optimally run the query and buffer data for future queries, subject to limitations imposed by:   - SQL Server max server memory setting. If this configuration option is set, the buffer pool is not allowed to grow to more than this value. In SQL Server 2008 this value represents single page allocations, and in “Denali” it represents any size page allocations and also managed CLR procedure allocations.   - Memory signals from OS. The operating system sets a signal on memory resource notification objects to indicate whether it has memory available or whether it is low on available memory. If there is only 32MB free for every 4GB of memory a low memory signal is set, which continues until 64MB/4GB is free. If there is 96MB/4GB free the operating system sets a high memory signal. SQL Server only allocates memory when the high memory signal is set.   To summarize, for SQL Server to grow you need three conditions: a workload, max server memory setting higher than the current allocation, high memory signals from the OS.    When does SQL Server shrink caches? SQL Server as a rule does not like to return memory to the OS, but it will shrink its caches in response to memory pressure. Memory pressure can be divided into “internal” and “external”.   - External memory pressure occurs when the operating system is running low on memory and low memory signals are set. The SQL Server Resource Monitor checks for low memory signals approximately every 5 seconds and it will attempt to free memory until the signals stop.   To free memory SQL Server does the following: ·         Frees unused memory. ·         Notifies Memory Manager Clients to release memory o   Caches – Free unreferenced cache objects. o   Buffer pool - Based on oldest access times.   The freed memory is released back to the operating system. This process continues until the low memory resource notifications stop.    - Internal memory pressure occurs when the size of different caches and allocations increase but the SQL Server process needs to keep its total memory within a target value. For example if max server memory is set and certain caches are growing large, it will cause SQL to free memory for re-use internally, but not to release memory back to the OS. If you lower the value of max server memory you will generate internal memory pressure that will cause SQL to release memory back to the OS.    Memory pressure handling has not changed much since SQL 2005 and it was described in detail in a blog post by Slava Oks.   Note that SQL Server Express is an exception to the above behavior. Unlike other editions it does not assume it is the most important process running on the system but tries to be more “desktop” friendly. It will empty its working set after a period of inactivity.   How does SQL Server respond to changing OS memory?    In SQL Server 2005 support for Hot-Add memory was introduced. This feature, available in Enterprise and above editions, allows the server to make use of any extra physical memory that was added after SQL Server started. Being able to add physical memory when the system is running is limited to specialized hardware, but with the Hyper-V Dynamic Memory feature, when new memory is allocated to a guest virtual machine, it looks like hot-add physical memory to the guest. What this means is that thanks to the hot-add memory feature, SQL Server 2005 and higher can dynamically grow if more “physical” memory is granted to a guest VM by Hyper-V dynamic memory.   SQL Server checks OS memory every second and dynamically adjusts its “target” (based on available OS memory and max server memory) accordingly.   In “Denali” Standard Edition will also have sqlserver.exe support for hot-add memory when running virtualized (i.e. detecting and acting on Hyper-V Dynamic Memory allocations).   How does a SQL Server workload in a guest VM impact Hyper-V dynamic memory scheduling?   When a SQL workload causes the sqlserver.exe process to grow its working set, the Hyper-V memory scheduler will detect memory pressure in the guest VM and add memory to it. SQL Server will then detect the extra memory and grow according to workload demand. In our tests we have seen this feedback process cause a guest VM to grow quickly in response to SQL workload - we are still working on characterizing this ramp-up.    How does SQL Server respond when Hyper-V removes memory from a guest VM through ballooning?   If pressure from other VM's cause Hyper-V Dynamic Memory to take memory away from a VM through ballooning (allocating memory with a virtual device driver and returning it to the host OS), Windows Memory Manager will page out unlocked portions of memory and signal low resource notification events. When SQL Server detects these events it will shrink memory until the low memory notifications stop (see cache shrinking description above).    This raises another question. Can we make SQL Server release memory more readily and hence behave more "dynamically" without compromising performance? In certain circumstances where the application workload is predictable it may be possible to have a job which varies "max server memory" according to need, lowering it when the engine is inactive and raising it before a period of activity. This would have limited applicaability but it is something we're looking into.   What Memory Management changes are there in SQL Server “Denali”?   In SQL Server “Denali” (aka SQL11) the Memory Manager has been re-written to be more efficient. The main changes are summarized in this post. An important change with respect to Hyper-V Dynamic Memory support is that now the max server memory setting includes any size page allocations and managed CLR procedure allocations it now represents a closer approximation to total sqlserver.exe memory usage. This makes it easier to calculate a value for max server memory, which becomes important when configuring virtual machines to work well with Hyper-V Dynamic Memory Startup and Maximum RAM settings.   Another important change is no more AWE or hot-add support for 32-bit edition. This means if you're running a 32-bit edition of Denali you're limited to a 4GB address space and will not be able to take advantage of dynamically added OS memory that wasn't present when SQL Server started (though Hyper-V Dynamic Memory is still a supported configuration).   In part 3 we’ll develop some best practices for configuring and using SQL Server with Dynamic Memory. Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• Transactional Messaging in the Windows Azure Service Bus

  - by Alan Smith

  Introduction I’m currently working on broadening the content in the Windows Azure Service Bus Developer Guide. One of the features I have been looking at over the past week is the support for transactional messaging. When using the direct programming model and the WCF interface some, but not all, messaging operations can participate in transactions. This allows developers to improve the reliability of messaging systems. There are some limitations in the transactional model, transactions can only include one top level messaging entity (such as a queue or topic, subscriptions are no top level entities), and transactions cannot include other systems, such as databases. As the transaction model is currently not well documented I have had to figure out how things work through experimentation, with some help from the development team to confirm any questions I had. Hopefully I’ve got the content mostly correct, I will update the content in the e-book if I find any errors or improvements that can be made (any feedback would be very welcome). I’ve not had a chance to look into the code for transactions and asynchronous operations, maybe that would make a nice challenge lab for my Windows Azure Service Bus course. Transactional Messaging Messaging entities in the Windows Azure Service Bus provide support for participation in transactions. This allows developers to perform several messaging operations within a transactional scope, and ensure that all the actions are committed or, if there is a failure, none of the actions are committed. There are a number of scenarios where the use of transactions can increase the reliability of messaging systems. Using TransactionScope In .NET the TransactionScope class can be used to perform a series of actions in a transaction. The using declaration is typically used de define the scope of the transaction. Any transactional operations that are contained within the scope can be committed by calling the Complete method. If the Complete method is not called, any transactional methods in the scope will not commit.   // Create a transactional scope. using (TransactionScope scope = new TransactionScope()) {     // Do something.       // Do something else.       // Commit the transaction.     scope.Complete(); }     In order for methods to participate in the transaction, they must provide support for transactional operations. Database and message queue operations typically provide support for transactions. Transactions in Brokered Messaging Transaction support in Service Bus Brokered Messaging allows message operations to be performed within a transactional scope; however there are some limitations around what operations can be performed within the transaction. In the current release, only one top level messaging entity, such as a queue or topic can participate in a transaction, and the transaction cannot include any other transaction resource managers, making transactions spanning a messaging entity and a database not possible. When sending messages, the send operations can participate in a transaction allowing multiple messages to be sent within a transactional scope. This allows for “all or nothing” delivery of a series of messages to a single queue or topic. When receiving messages, messages that are received in the peek-lock receive mode can be completed, deadlettered or deferred within a transactional scope. In the current release the Abandon method will not participate in a transaction. The same restrictions of only one top level messaging entity applies here, so the Complete method can be called transitionally on messages received from the same queue, or messages received from one or more subscriptions in the same topic. Sending Multiple Messages in a Transaction A transactional scope can be used to send multiple messages to a queue or topic. This will ensure that all the messages will be enqueued or, if the transaction fails to commit, no messages will be enqueued.     An example of the code used to send 10 messages to a queue as a single transaction from a console application is shown below.   QueueClient queueClient = messagingFactory.CreateQueueClient(Queue1);   Console.Write("Sending");   // Create a transaction scope. using (TransactionScope scope = new TransactionScope()) {     for (int i = 0; i < 10; i++)     {         // Send a message         BrokeredMessage msg = new BrokeredMessage("Message: " + i);         queueClient.Send(msg);         Console.Write(".");     }     Console.WriteLine("Done!");     Console.WriteLine();       // Should we commit the transaction?     Console.WriteLine("Commit send 10 messages? (yes or no)");     string reply = Console.ReadLine();     if (reply.ToLower().Equals("yes"))     {         // Commit the transaction.         scope.Complete();     } } Console.WriteLine(); messagingFactory.Close();     The transaction scope is used to wrap the sending of 10 messages. Once the messages have been sent the user has the option to either commit the transaction or abandon the transaction. If the user enters “yes”, the Complete method is called on the scope, which will commit the transaction and result in the messages being enqueued. If the user enters anything other than “yes”, the transaction will not commit, and the messages will not be enqueued. Receiving Multiple Messages in a Transaction The receiving of multiple messages is another scenario where the use of transactions can improve reliability. When receiving a group of messages that are related together, maybe in the same message session, it is possible to receive the messages in the peek-lock receive mode, and then complete, defer, or deadletter the messages in one transaction. (In the current version of Service Bus, abandon is not transactional.)   The following code shows how this can be achieved. using (TransactionScope scope = new TransactionScope()) {       while (true)     {         // Receive a message.         BrokeredMessage msg = q1Client.Receive(TimeSpan.FromSeconds(1));         if (msg != null)         {             // Wrote message body and complete message.             string text = msg.GetBody<string>();             Console.WriteLine("Received: " + text);             msg.Complete();         }         else         {             break;         }     }     Console.WriteLine();       // Should we commit?     Console.WriteLine("Commit receive? (yes or no)");     string reply = Console.ReadLine();     if (reply.ToLower().Equals("yes"))     {         // Commit the transaction.         scope.Complete();     }     Console.WriteLine(); }     Note that if there are a large number of messages to be received, there will be a chance that the transaction may time out before it can be committed. It is possible to specify a longer timeout when the transaction is created, but It may be better to receive and commit smaller amounts of messages within the transaction. It is also possible to complete, defer, or deadletter messages received from more than one subscription, as long as all the subscriptions are contained in the same topic. As subscriptions are not top level messaging entities this scenarios will work. The following code shows how this can be achieved. try {     using (TransactionScope scope = new TransactionScope())     {         // Receive one message from each subscription.         BrokeredMessage msg1 = subscriptionClient1.Receive();         BrokeredMessage msg2 = subscriptionClient2.Receive();           // Complete the message receives.         msg1.Complete();         msg2.Complete();           Console.WriteLine("Msg1: " + msg1.GetBody<string>());         Console.WriteLine("Msg2: " + msg2.GetBody<string>());           // Commit the transaction.         scope.Complete();     } } catch (Exception ex) {     Console.WriteLine(ex.Message); }     Unsupported Scenarios The restriction of only one top level messaging entity being able to participate in a transaction makes some useful scenarios unsupported. As the Windows Azure Service Bus is under continuous development and new releases are expected to be frequent it is possible that this restriction may not be present in future releases. The first is the scenario where messages are to be routed to two different systems. The following code attempts to do this.   try {     // Create a transaction scope.     using (TransactionScope scope = new TransactionScope())     {         BrokeredMessage msg1 = new BrokeredMessage("Message1");         BrokeredMessage msg2 = new BrokeredMessage("Message2");           // Send a message to Queue1         Console.WriteLine("Sending Message1");         queue1Client.Send(msg1);           // Send a message to Queue2         Console.WriteLine("Sending Message2");         queue2Client.Send(msg2);           // Commit the transaction.         Console.WriteLine("Committing transaction...");         scope.Complete();     } } catch (Exception ex) {     Console.WriteLine(ex.Message); }     The results of running the code are shown below. When attempting to send a message to the second queue the following exception is thrown: No active Transaction was found for ID '35ad2495-ee8a-4956-bbad-eb4fedf4a96e:1'. The Transaction may have timed out or attempted to span multiple top-level entities such as Queue or Topic. The server Transaction timeout is: 00:01:00..TrackingId:947b8c4b-7754-4044-b91b-4a959c3f9192_3_3,TimeStamp:3/29/2012 7:47:32 AM.   Another scenario where transactional support could be useful is when forwarding messages from one queue to another queue. This would also involve more than one top level messaging entity, and is therefore not supported.   Another scenario that developers may wish to implement is performing transactions across messaging entities and other transactional systems, such as an on-premise database. In the current release this is not supported.   Workarounds for Unsupported Scenarios There are some techniques that developers can use to work around the one top level entity limitation of transactions. When sending two messages to two systems, topics and subscriptions can be used. If the same message is to be sent to two destinations then the subscriptions would have the default subscriptions, and the client would only send one message. If two different messages are to be sent, then filters on the subscriptions can route the messages to the appropriate destination. The client can then send the two messages to the topic in the same transaction.   In scenarios where a message needs to be received and then forwarded to another system within the same transaction topics and subscriptions can also be used. A message can be received from a subscription, and then sent to a topic within the same transaction. As a topic is a top level messaging entity, and a subscription is not, this scenario will work.

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• OBIEE 11.1.1 - Disable Wrap Data Types in WebLogic Server 10.3.x

  - by Ahmed Awan

  By default, JDBC data type’s objects are wrapped with a WebLogic wrapper. This allows for features like debugging output and track connection usage to be done by the server. The wrapping can be turned off by setting this value to false. This improves performance, in some cases significantly, and allows for the application to use the native driver objects directly. Tip: How to Disable Wrapping in WLS Administration Console You can use the Administration Console to disable data type wrapping for following JDBC data sources in bifoundation_domain domain: Data Source Name bip_datasource mds-owsm EPMSystemRegistry   To disable wrapping for each JDBC data source (as stated in above table): 1.     If you have not already done so, in the Change Center of the Administration Console, click Lock & Edit. 2.     In the Domain Structure tree, expand Services, then select Data Sources. 3.     On the Summary of Data Sources page, click the data source name for example “mds-owsm”. 4.     Select the Configuration: Connection Pool tab. 5.     Scroll down and click Advanced to show the advanced connection pool options. 6.     In Wrap Data Types, deselect the checkbox to disable wrapping. 7.     Click Save. 8.     To activate these changes, in the Change Center of the Administration Console, click Activate Changes. Important Note: This change does not take effect immediately—it requires the server be restarted.

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• SQLAuthority News – Best SQLAuthority Posts of May

  - by pinaldave

  Month of May is always interesting and full of enthusiasm. Lots of good articles shared and lots of enthusiast communication on technology. This month we had 140 Character Cartoon Challenge Winner. We also had interesting conversation on what kind of lock WITH NOLOCK takes on objects as well. A quick tutorial on how to import CSV files into Database using SSIS started few other related questions. I also had fun time with community activities. I attended MVP Open Day. Vijay Raj also took awesome photos of my daughter – Shaivi. I have gain my faith back in Social Media and have created my Facebook Page, if you like SQLAuthority.com I request you to Like Facebook page as well. I am very active on twitter (@pinaldave) and answer lots of technical question if I am online during that time. During this month couple of old thing, I did learn by accident 1) Restart and Shutdown Remote Computer 2) SSMS has web browser. If you have made it till here – I suggest you to take participation in very interesting conversation here – Why SELECT * throws an error but SELECT COUNT(*) does not? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Earth’s Radiation Belt Sounds like Whale Song [Video]

  - by Jason Fitzpatrick

  The radio frequencies of Earth’s radiation belt have uncanny resemblance to a sort of whale/bird song remix. Check out this video to learn more about NASA’s efforts to explore the belts and listen to the Earth’s song. When we hear the “song” of the Earth, exactly what are we hearing? Science@NASA explains: Chorus is an electromagnetic phenomenon caused by plasma waves in Earth’s radiation belts. For years, ham radio operators on Earth have been listening to them from afar. Now, NASA’s twin Radiation Belt Storm Probes are traveling through the region of space where chorus actually comes from–and the recordings are out of this world. “This is what the radiation belts would sound like to a human being if we had radio antennas for ears,” says Kletzing, whose team at the University of Iowa built the “EMFISIS” (Electric and Magnetic Field Instrument Suite and Integrated Science) receiver used to pick up the signals. He’s careful to point out that these are not acoustic waves of the kind that travel through the air of our planet. Chorus is made of radio waves that oscillate at acoustic frequencies, between 0 and 10 kHz. The magnetic search coil antennas of the Radiation Belt Storm Probes are designed to detect these kinds of waves. HTG Explains: How Antivirus Software Works HTG Explains: Why Deleted Files Can Be Recovered and How You Can Prevent It HTG Explains: What Are the Sys Rq, Scroll Lock, and Pause/Break Keys on My Keyboard?

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• Podcast Show Notes: Evolving Enterprise Architecture

  - by Bob Rhubart

  Back in March Oracle ACE Directors Mike van Alst (IT-Eye) and Jordan Braunstein (Visual Integrator Consulting) and Oracle product manager Jeff Davies participated in an ArchBeat virtual meet-up. The resulting conversation quickly turned to the changing nature of enterprise architecture and the various forces driving that change. All four parts of that wide-ranging conversation are now available. Listen to Part 1 Listen to Part 2 Listen to Part 3 Listen to Part 4 As you’ll hear, Mike, Jordan, and Jeff bring unique perspectives and opinions to this very lively conversation. These are three very sharp, very experienced guys, as and you might expect, they don’t always walk in lock-step when it comes to EA. You can learn more about Mike, Jordan, and Jeff – and share your opinions with them -- through the links below: Mike van Alst Blog | Twitter | LinkedIn | Business |Oracle Mix | Oracle ACE Profile Jordan Braunstein Blog | Twitter | LinkedIn | Business | Oracle Mix | Oracle ACE Profile Jeff Davies Homepage | Blog | LinkedIn | Oracle Mix (Also check out Jeff’s book: The Definitive Guide to SOA: Oracle Service Bus) Up Next Next week’s program features highlights from the panel discussion at the Oracle Technology Architect Day event held in Anaheim, CA on May 19. You’ll hear from Oracle ACE Directors Basheer Khan and Floyd Teter, Oracle virtualization expert and former Sun Microsystems principal engineer Jeff Savit, Oracle security analyst Geri Born, and event MC Ralf Dossman, Director of SOA and Middleware in Oracle’s Enterprise Solutions Group. Stay tuned: RSS

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• Ask How-To Geek: Diagnosing DSL Hang Ups, Extracting Media from PowerPoint, Restricting IE to a Single Web Page

  - by Jason Fitzpatrick

  This week we take a look at flaky DSL connections, extracting media from PowerPoint presentations, and how to lock down IE to a single website without any additional software or network configuration hacking necessary. Once a week we dip into our reader mailbag and help readers solve their problems, sharing the useful solutions with you in the process. Read on to see our fixes for this week’s reader dilemmas. Latest Features How-To Geek ETC How to Get Amazing Color from Photos in Photoshop, GIMP, and Paint.NET Learn To Adjust Contrast Like a Pro in Photoshop, GIMP, and Paint.NET Have You Ever Wondered How Your Operating System Got Its Name? Should You Delete Windows 7 Service Pack Backup Files to Save Space? What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? Page Zipper Unpacks Multi-Page Articles for Single-Page Display Minty Bug: Build an FM Bug Inside a Mint Container Get the MakeUseOf eBook Guide to Hacker Proofing Your PC Sync Your Windows Computer with Your Ubuntu One Account [Desktop Client] Awesome 10 Meter Curved Touchscreen at the University of Groningen [Video] TV Antenna Helper Makes HDTV Antenna Calibration a Snap

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• Desktop Fun: Dual Monitor Wallpaper Collection Series 2

  - by Asian Angel

  Last month we brought you the first batch of wallpapers geared specifically towards dual monitor setups. Today we present the second offering in our series of dual monitor wallpaper collections. Note: Click on the picture to see the full-size image—these wallpapers vary in size so you may need to crop, stretch, or place them on a colored background in order to best match them to your screen’s resolution. More Dual Monitor Goodness Desktop Fun: Dual Monitor Wallpaper Collection Series 1 Span the same wallpaper across two monitors or use a different wallpaper for each. Dual Monitors: Use a Different Wallpaper on Each Desktop in Windows 7, Vista or XP For more wallpapers be certain to see our great collections in the Desktop Fun section. Latest Features How-To Geek ETC The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Tune Pop Enhances Android Music Notifications Another Busy Night in Gotham City Wallpaper Classic Super Mario Brothers Theme for Chrome and Iron Experimental Firefox Builds Put Tabs on the Title Bar (Available for Download) Android Trojan Found in the Wild Chaos, Panic, and Disorder Wallpaper

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• SQLAuthority News – Fast Track Data Warehouse 3.0 Reference Guide

  - by pinaldave

  http://msdn.microsoft.com/en-us/library/gg605238.aspx I am very excited that Fast Track Data Warehouse 3.0 reference guide has been announced. As a consultant I have always enjoyed working with Fast Track Data Warehouse project as it truly expresses the potential of the SQL Server Engine. Here is few details of the enhancement of the Fast Track Data Warehouse 3.0 reference architecture. The SQL Server Fast Track Data Warehouse initiative provides a basic methodology and concrete examples for the deployment of balanced hardware and database configuration for a data warehousing workload. Balance is measured across the key components of a SQL Server installation; storage, server, application settings, and configuration settings for each component are evaluated. Description Note FTDW 3.0 Architecture Basic component architecture for FT 3.0 based systems. New Memory Guidelines Minimum and maximum tested memory configurations by server socket count. Additional Startup Options Notes for T-834 and setting for Lock Pages in Memory. Storage Configuration RAID1+0 now standard (RAID1 was used in FT 2.0). Evaluating Fragmentation Query provided for evaluating logical fragmentation. Loading Data Additional options for CI table loads. MCR Additional detail and explanation of FTDW MCR Rating. Read white paper on fast track data warehousing. Reference: Pinal Dave (http://blog.SQLAuthority.com)   Filed under: Business Intelligence, Data Warehousing, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, SQLAuthority News, T SQL, Technology

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• Mount SMB / AFP 13.10

  - by Jeffery

  I cannot seem to get Ubuntu to mount a mac share via SMB or AFP. I've tried the following... AFP: apt-get install afpfs-ng-utils mount_afp afp://user:password@localip/share /mnt/share Error given: "Could not connect, never got a reponse to getstatus, Connection timed out". Which is odd as I can access the share just fine via Mac. SMB: apt-get install cifs-utils nano /etc/fstab added the following line "//localip/share /mnt/share cifs username=user,password=pass,iocharset=utf8,sec=nltm 0 0" mount -a Error given: root@Asrock:~# mount -a -vvv mount: fstab path: "/etc/fstab" mount: mtab path: "/etc/mtab" mount: lock path: "/etc/mtab~" mount: temp path: "/etc/mtab.tmp" mount: UID: 0 mount: eUID: 0 mount: spec: "//10.0.1.3/NAS" mount: node: "/mnt/NAS" mount: types: "cifs" mount: opts: "username=user,password=pass,iocharset=utf8,sec=nltm" mount: external mount: argv[0] = "/sbin/mount.cifs" mount: external mount: argv[1] = "//10.0.1.3/NAS" mount: external mount: argv[2] = "/mnt/NAS" mount: external mount: argv[3] = "-v" mount: external mount: argv[4] = "-o" mount: external mount: argv[5] = "rw,username=user,password=pass,iocharset=utf8,sec=nltm" mount.cifs kernel mount options: ip=10.0.1.3,unc=\\10.0.1.3\NAS,iocharset=utf8,sec=nltm,user=user,pass=* mount error(22): Invalid argument Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) I don't really care which it uses I just want it to work! Am I doing something wrong?

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• system overrides my mount parameters in /etc/fstab

  - by valya

  [.../~]$ mount /dev/sda4 on / type ext4 (rw,commit=60,commit=0) [.../~]$ cat /etc/fstab # UNCONFIGURED FSTAB FOR BASE SYSTEM UUID=70739c04-fcb6-4747-803c-824f9c894f41 / ext4 defaults,commit=60 0 1 What can I do about it? It seems strange. I want to be able to set any commit time I want Edit: added /proc/mounts contents [.../~]$ cat /proc/mounts rootfs / rootfs rw 0 0 none /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0 none /proc proc rw,nosuid,nodev,noexec,relatime 0 0 none /dev devtmpfs rw,relatime,size=886332k,nr_inodes=221583,mode=755 0 0 none /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0 fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0 /dev/disk/by-uuid/70739c04-fcb6-4747-803c-824f9c894f41 / ext4 rw,relatime,barrier=1,data=ordered 0 0 none /sys/kernel/debug debugfs rw,relatime 0 0 none /sys/kernel/security securityfs rw,relatime 0 0 none /dev/shm tmpfs rw,nosuid,nodev,relatime 0 0 none /var/run tmpfs rw,nosuid,relatime,mode=755 0 0 none /var/lock tmpfs rw,nosuid,nodev,noexec,relatime 0 0 /dev/sda3 /media/megahard fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096 0 0 cgroup /dev/cgroup/cpu cgroup rw,relatime,cpu,release_agent=/usr/local/sbin/cgroup_clean 0 0 gvfs-fuse-daemon /home/va1en0k/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0

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• Samba Server Make Multiple User Permissions Profiles

  - by Scriptonaut

  I have a Samba file server running, and I was wondering how I could make multiple user accounts that have different permissions. For example, at the moment I have a user, smbusr, but when I ssh to the share, I can read, write, execute, and even navigate out of the samba directory and do stuff on the actual computer. This is bad because I want to be able to give out my IP so friends/family can use the server, but I don't want them to be able to do just anything. I want to lock the user in the samba share directory(and all the sub directories). Eventually I would like several profiles such as (smbusr_R, smbusr_RW, smbguest_R, smbguest_RW). I also have a second question related to this, is SSH the best method to connect from other unix machines? What about VPN? Or simply mounting like this: mount -t ext3 -o user=username //ipaddr/share /mnt/mountpoint Is that mounting command above the same thing as a vpn? This is really confusing me. Thanks for the help guys, let me know if you need to see any files, or need anymore information.

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• Thunderbird compact is taking forever

  - by mulllhausen

  One day I came in to work and found that our development server - a Ubuntu box had a full hard disk. I did a bit of investigation using the du command and it seems like mozilla thunderbird is the major culprit. After burning off some backups, the disk was left at 94%: $ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 895G 791G 59G 94% / none 4.0G 300K 4.0G 1% /dev none 4.0G 1.4M 4.0G 1% /dev/shm none 4.0G 140K 4.0G 1% /var/run none 4.0G 0 4.0G 0% /var/lock none 4.0G 0 4.0G 0% /lib/init/rw $ cd $ du -ch | grep [0-9]G 666G ./.thunderbird/ccsmcruu.default/ImapMail/mail.adofms.com.au 666G ./.thunderbird/ccsmcruu.default/ImapMail 667G ./.thunderbird/ccsmcruu.default 667G ./.thunderbird 2.2G ./.VirtualBox/Machines/iBike/Snapshots 2.2G ./.VirtualBox/Machines/iBike 2.2G ./.VirtualBox/Machines 2.2G ./.VirtualBox 670G . 670G total I did some reading and found that Mozilla Thunderbird does not compact files by default - i.e. all of the old emails that were sent to trash are still kept. One of the mailboxes used to get a lot of spam so I guess this accounts for the 667GB. I opened up Thunderbird to see how much space the inbox actually takes up and it turns out to be approximately 500MB - over 1000 times less than the stuff that has not been compacted over the years. So i right clicked on the inbox directory in the tree on the left of Thunderbird and selected 'compact'. I left it for about 12hours but even after that it still said 'compacting folder' on the status bar. I don't use Thunderbird on this PC - it belonged to a colleague who has left the company, however I do occasionally need to look through the inbox for references to the project I am working on, so deleting all traces of Thunderbird is not an option. My question is - is there any way I can monitor the progress of Thunderbird's compacting function? I would really like to know how long it is going to take. Also is there any way I can speed up the compacting process?

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• Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

  - by Bakhtiyor

  I have mailserver configure using dovecot+postfix+mysql and it was runnig fine in the server(Ubuntu Server). But during last week it stopped working correctly. It doesn't send email. When I try to telnet localhost smtp I'm connecting successfully but when I do mail from:<[email protected]> and hit Enter it hangs on, nothing happen. Having reviewed /var/log/mail.log file I've found out that probably(99%) the problem is on postfix when it is trying to connect to MySQL server. If you see the log file given below you can see that it says Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2). Nov 14 21:54:36 ns1 dovecot: dovecot: Killed with signal 15 (by pid=7731 uid=0 code=kill) Nov 14 21:54:36 ns1 dovecot: Dovecot v1.2.9 starting up (core dumps disabled) Nov 14 21:54:36 ns1 dovecot: auth-worker(default): mysql: Connected to localhost (mailserver) Nov 14 21:54:44 ns1 postfix/postfix-script[7753]: refreshing the Postfix mail system Nov 14 21:54:44 ns1 postfix/master[1670]: reload -- version 2.7.0, configuration /etc/postfix Nov 14 21:54:52 ns1 postfix/trivial-rewrite[7759]: warning: connect to mysql server localhost: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) Nov 14 21:54:52 ns1 postfix/trivial-rewrite[7759]: fatal: mysql:/etc/postfix/mysql-virtual-alias-maps.cf(0,lock|fold_fix): table lookup problem Nov 14 21:54:53 ns1 postfix/master[1670]: warning: process /usr/lib/postfix/trivial-rewrite pid 7759 exit status 1 Nov 14 21:54:53 ns1 postfix/cleanup[7397]: warning: problem talking to service rewrite: Connection reset by peer Nov 14 21:54:53 ns1 postfix/master[1670]: warning: /usr/lib/postfix/trivial-rewrite: bad command startup -- throttling Nov 14 21:54:53 ns1 postfix/smtpd[7071]: warning: problem talking to service rewrite: Success I tried netstat -ln | grep mysql and it returns unix 2 [ ACC ] STREAM LISTENING 5817 /var/run/mysqld/mysqld.sock. The content of /etc/postfix/mysql-virtual-alias-maps.cf file is here: user = stevejobs password = apple hosts = localhost dbname = mailserver query = SELECT destination FROM virtual_aliases WHERE source='%s' Here I tried to change hosts = 127.0.0.1 but it says warning: connect to mysql server 127.0.0.1: Can't connect to MySQL server on '127.0.0.1' (110) So, I am lost and don't know where else to change in order to solve the problem. Any help would be appreciated highly. Thank you.

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• Can&rsquo;t eject external USB or Firewire drive in Windows 7

  - by Kelly Jones

  As a SharePoint developer, I work a lot with Virtual Machines (presently using Windows Virtual PC, with Windows 7).  I’m using these VMs with my laptop, and in order to get better performance, I’ve moved them to external hard drives.  (These drives have faster RPMs, larger caches, and a larger capacity, than the internal drive.)  I have one large external drive at home, another similar drive at the office, and a small, slow portable drive that I carry with me. So, at the end of each day at the office, I copy the files from the external drive to my portable drive and then once I get home, I copy them from the portable to the larger external drive I leave at home.  I do this for a couple of reasons: so I can work at home and secondly, so I have backup copies.  (Often, I feel like I’m in the movie “Office Space” when copying the files before I leave the office). Anyway, after the files are copied, I safely eject the external drives, and then hibernate my laptop.  I’ve been doing this for over a year now, but within the last couple of months I started to have issues disconnecting the drives.  Intermittently, some application/process would have a lock on some file on the drive that would keep Windows from safely ejecting it. After looking into it, I found that it was actually the Windows search service that was accessing the drive! Since I wasn’t using Windows search to look for stuff on these drives, I removed them as locations to index. To do this in Windows 7, you need to go to Indexing Options (just type “Indexing” into the search box in the Start menu…).  One of the choices displayed will then be Indexing Options, so click on it and you should then see a window similar to this:   Click on the Modify button and you’ll see this window: Notice the different drives listed above.  My “FreeAgent XTreme (F:)” drive was checked for some reason, which was causing the indexing service to scan the drive looking for new files to make available in the search results.  Ever since I unchecked this box, I’ve been able to safely eject the drive.

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• Following the Thread in OSB

  - by Antony Reynolds

  Threading in OSB The Scenario I recently led an OSB POC where we needed to get high throughput from an OSB pipeline that had the following logic: 1. Receive Request 2. Send Request to External System 3. If Response has a particular value   3.1 Modify Request   3.2 Resend Request to External System 4. Send Response back to Requestor All looks very straightforward and no nasty wrinkles along the way.  The flow was implemented in OSB as follows (see diagram for more details): Proxy Service to Receive Request and Send Response Request Pipeline   Copies Original Request for use in step 3 Route Node   Sends Request to External System exposed as a Business Service Response Pipeline   Checks Response to Check If Request Needs to Be Resubmitted Modify Request Callout to External System (same Business Service as Route Node) The Proxy and the Business Service were each assigned their own Work Manager, effectively giving each of them their own thread pool. The Surprise Imagine our surprise when, on stressing the system we saw it lock up, with large numbers of blocked threads.  The reason for the lock up is due to some subtleties in the OSB thread model which is the topic of this post.   Basic Thread Model OSB goes to great lengths to avoid holding on to threads.  Lets start by looking at how how OSB deals with a simple request/response routing to a business service in a route node. Most Business Services are implemented by OSB in two parts.  The first part uses the request thread to send the request to the target.  In the diagram this is represented by the thread T1.  After sending the request to the target (the Business Service in our diagram) the request thread is released back to whatever pool it came from.  A multiplexor (muxer) is used to wait for the response.  When the response is received the muxer hands off the response to a new thread that is used to execute the response pipeline, this is represented in the diagram by T2. OSB allows you to assign different Work Managers and hence different thread pools to each Proxy Service and Business Service.  In out example we have the “Proxy Service Work Manager” assigned to the Proxy Service and the “Business Service Work Manager” assigned to the Business Service.  Note that the Business Service Work Manager is only used to assign the thread to process the response, it is never used to process the request. This architecture means that while waiting for a response from a business service there are no threads in use, which makes for better scalability in terms of thread usage. First Wrinkle Note that if the Proxy and the Business Service both use the same Work Manager then there is potential for starvation.  For example: Request Pipeline makes a blocking callout, say to perform a database read. Business Service response tries to allocate a thread from thread pool but all threads are blocked in the database read. New requests arrive and contend with responses arriving for the available threads. Similar problems can occur if the response pipeline blocks for some reason, maybe a database update for example. Solution The solution to this is to make sure that the Proxy and Business Service use different Work Managers so that they do not contend with each other for threads. Do Nothing Route Thread Model So what happens if there is no route node?  In this case OSB just echoes the Request message as a Response message, but what happens to the threads?  OSB still uses a separate thread for the response, but in this case the Work Manager used is the Default Work Manager. So this is really a special case of the Basic Thread Model discussed above, except that the response pipeline will always execute on the Default Work Manager.   Proxy Chaining Thread Model So what happens when the route node is actually calling a Proxy Service rather than a Business Service, does the second Proxy Service use its own Thread or does it re-use the thread of the original Request Pipeline? Well as you can see from the diagram when a route node calls another proxy service then the original Work Manager is used for both request pipelines.  Similarly the response pipeline uses the Work Manager associated with the ultimate Business Service invoked via a Route Node.  This actually fits in with the earlier description I gave about Business Services and by extension Route Nodes they “… uses the request thread to send the request to the target”. Call Out Threading Model So what happens when you make a Service Callout to a Business Service from within a pipeline.  The documentation says that “The pipeline processor will block the thread until the response arrives asynchronously” when using a Service Callout.  What this means is that the target Business Service is called using the pipeline thread but the response is also handled by the pipeline thread.  This implies that the pipeline thread blocks waiting for a response.  It is the handling of this response that behaves in an unexpected way. When a Business Service is called via a Service Callout, the calling thread is suspended after sending the request, but unlike the Route Node case the thread is not released, it waits for the response.  The muxer uses the Business Service Work Manager to allocate a thread to process the response, but in this case processing the response means getting the response and notifying the blocked pipeline thread that the response is available.  The original pipeline thread can then continue to process the response. Second Wrinkle This leads to an unfortunate wrinkle.  If the Business Service is using the same Work Manager as the Pipeline then it is possible for starvation or a deadlock to occur.  The scenario is as follows: Pipeline makes a Callout and the thread is suspended but still allocated Multiple Pipeline instances using the same Work Manager are in this state (common for a system under load) Response comes back but all Work Manager threads are allocated to blocked pipelines. Response cannot be processed and so pipeline threads never unblock – deadlock! Solution The solution to this is to make sure that any Business Services used by a Callout in a pipeline use a different Work Manager to the pipeline itself. The Solution to My Problem Looking back at my original workflow we see that the same Business Service is called twice, once in a Routing Node and once in a Response Pipeline Callout.  This was what was causing my problem because the response pipeline was using the Business Service Work Manager, but the Service Callout wanted to use the same Work Manager to handle the responses and so eventually my Response Pipeline hogged all the available threads so no responses could be processed. The solution was to create a second Business Service pointing to the same location as the original Business Service, the only difference was to assign a different Work Manager to this Business Service.  This ensured that when the Service Callout completed there were always threads available to process the response because the response processing from the Service Callout had its own dedicated Work Manager. Summary Request Pipeline Executes on Proxy Work Manager (WM) Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. Route Node Request sent using Proxy WM Thread Proxy WM Thread is released before getting response Muxer is used to handle response Muxer hands off response to Business Service (BS) WM Response Pipeline Executes on Routed Business Service WM Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. No Route Node (Echo functionality) Proxy WM thread released New thread from the default WM used for response pipeline Service Callout Request sent using proxy pipeline thread Proxy thread is suspended (not released) until the response comes back Notification of response handled by BS WM thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. Note this is a very short lived use of the thread After notification by callout BS WM thread that thread is released and execution continues on the original pipeline thread. Route/Callout to Proxy Service Request Pipeline of callee executes on requestor thread Response Pipeline of caller executes on response thread of requested proxy Throttling Request message may be queued if limit reached. Requesting thread is released (route node) or suspended (callout) So what this means is that you may get deadlocks caused by thread starvation if you use the same thread pool for the business service in a route node and the business service in a callout from the response pipeline because the callout will need a notification thread from the same thread pool as the response pipeline.  This was the problem we were having. You get a similar problem if you use the same work manager for the proxy request pipeline and a business service callout from that request pipeline. It also means you may want to have different work managers for the proxy and business service in the route node. Basically you need to think carefully about how threading impacts your proxy services. References Thanks to Jay Kasi, Gerald Nunn and Deb Ayers for helping to explain this to me.  Any errors are my own and not theirs.  Also thanks to my colleagues Milind Pandit and Prasad Bopardikar who travelled this road with me. OSB Thread Model Great Blog Post on Thread Usage in OSB

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• How can I transfer files to a Kindle Fire with a Micro-USB cable?

  - by Jeff

  I'm running Ubuntu 11.10, and when I connect my Kindle Fire to my computer via micro usb, it is not recognized automatically. Other usb devices, such as my ipod and digital camera, are recognized just fine. It does not appear to be a usb power issue, since the Kindle Fire wakes up from sleeping when it is plugged in. I never get the message on the Kindle telling me it is ready to accept files from the computer, though. Here are the last 15 lines of dmesg after plugging the kindle in: jeff@prime:~$ dmesg | tail -n 15 [45918.269671] ieee80211 phy0: wl_ops_bss_info_changed: arp filtering: enabled true, count 1 (implement) [45929.072149] wlan0: no IPv6 routers present [46743.224217] usb 1-1: new high speed USB device number 5 using ehci_hcd [46743.364623] scsi8 : usb-storage 1-1:1.0 [46744.366102] scsi 8:0:0:0: Direct-Access Amazon Kindle 0001 PQ: 0 ANSI: 2 [46744.366356] scsi: killing requests for dead queue [46744.372494] scsi: killing requests for dead queue [46744.384510] scsi: killing requests for dead queue [46744.392348] scsi: killing requests for dead queue [46744.392731] scsi: killing requests for dead queue [46744.396853] scsi: killing requests for dead queue [46744.397214] scsi: killing requests for dead queue [46744.400795] scsi: killing requests for dead queue [46744.401589] sd 8:0:0:0: Attached scsi generic sg2 type 0 [46744.407520] sd 8:0:0:0: [sdb] Attached SCSI removable disk And here are my mounted filesystems: jeff@prime:~$ df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 298594984 174663712 108763480 62% / udev 1407684 4 1407680 1% /dev tmpfs 566924 896 566028 1% /run none 5120 0 5120 0% /run/lock none 1417308 300 1417008 1% /run/shm /home/jeff/.Private 298594984 174663712 108763480 62% /home/jeff I should note that, since I got Dropbox working on my Kindle, the usb is no longer strictly necessary, but as a matter of principle I'd love to get it working.

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• How to Combine Rescue Disks to Create the Ultimate Windows Repair Disk

  - by The Geek

  We’ve covered loads of different anti-virus, Linux, and other boot disks that help you repair or recover your system, but why limit yourself to just one? Here’s how to combine your favorite repair disks together to create the ultimate repair toolkit for broken Windows systems—all on a single flash drive. The ones we’ve covered already? Here’s a quick list of all the ways you can recover your system with a rescue disk: How to Use the Avira Rescue CD to Clean Your Infected PC How to Use the BitDefender Rescue CD to Clean Your Infected PC How to Use the Kaspersky Rescue Disk to Clean Your Infected PC Change or Reset Windows Password from a Ubuntu Live CD The 10 Cleverest Ways to Use Linux to Fix Your Windows PC Change Your Forgotten Windows Password with the Linux System Rescue CD Use Ubuntu Live CD to Backup Files from Your Dead Windows Computer If you need to clean up an infected system, we’d absolutely recommend the BitDefender CD, since it’s auto-updating. Best bet? Create your ultimate boot disk with as many of the different utilities as your flash drive can hold Latest Features How-To Geek ETC How To Boot 10 Different Live CDs From 1 USB Flash Drive The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC Luigi Installs Any OS on Google’s Cr-48 Notebook DIY iPad Stylus Offers Pen-Based Interaction on the Cheap Serene Blue Ubuntu Wallpaper for Your Desktop Enjoy Old School Style Video Game Fun with Chicken Invaders Hide the Twitter “Litter” in Twitter’s Sidebar Area (Chrome and Iron) Public Domain Day: Reflections on Copyright and the Importance of Public Domain

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• Reading and conditionally updating N rows, where N > 100,000 for DNA Sequence processing

  - by makerofthings7

  I have a proof of concept application that uses Azure tables to associate DNA sequences to "something". Table 1 is the master table. It uniquely lists every DNA sequence. The PK is a load balanced hash of the RK. The RK is the unique encoded value of the DNA sequence. Additional tables are created per subject. Each subject has a list of N DNA sequences that have one reference in the Master table, where N is 100,000. It is possible for many tables to reference the same DNA sequence, but in this case only one entry will be present in the Master table. My Azure dilemma: I need to lock the reference in the Master table as I work with the data. I need to handle timeouts, and prevent other threads from overwriting my data as one C# thread is working with the information. Other threads need to realise that this is locked, and move onto other unlocked records and do the work. Ideally I'd like to get some progress report of how my computation is going, and have the option to cancel the process (and unwind the locks). Question What is the best approach for this? I'm looking at these code snippets for inspiration: http://blogs.msdn.com/b/jimoneil/archive/2010/10/05/azure-home-part-7-asynchronous-table-storage-pagination.aspx http://stackoverflow.com/q/4535740/328397

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• SQL SERVER – Weekly Series – Memory Lane – #038

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 CASE Statement in ORDER BY Clause – ORDER BY using Variable This article is as per request from the Application Development Team Leader of my company. His team encountered code where the application was preparing string for ORDER BY clause of the SELECT statement. Application was passing this string as variable to Stored Procedure (SP) and SP was using EXEC to execute the SQL string. This is not good for performance as Stored Procedure has to recompile every time due to EXEC. sp_executesql can do the same task but still not the best performance. SSMS – View/Send Query Results to Text/Grid/Files Results to Text – CTRL + T Results to Grid – CTRL + D Results to File – CTRL + SHIFT + F 2008 Introduction to SPARSE Columns Part 2 I wrote about Introduction to SPARSE Columns Part 1. Let us understand the concept of the SPARSE column in more detail. I suggest you read the first part before continuing reading this article. All SPARSE columns are stored as one XML column in the database. Let us see some of the advantage and disadvantage of SPARSE column. Deferred Name Resolution How come when table name is incorrect SP can be created successfully but when an incorrect column is used SP cannot be created? 2009 Backup Timeline and Understanding of Database Restore Process in Full Recovery Model In general, databases backup in full recovery mode is taken in three different kinds of database files. Full Database Backup Differential Database Backup Log Backup Restore Sequence and Understanding NORECOVERY and RECOVERY While doing RESTORE Operation if you restoring database files, always use NORECOVER option as that will keep the database in a state where more backup file are restored. This will also keep database offline also to prevent any changes, which can create itegrity issues. Once all backup file is restored run RESTORE command with a RECOVERY option to get database online and operational. Four Different Ways to Find Recovery Model for Database Perhaps, the best thing about technical domain is that most of the things can be executed in more than one ways. It is always useful to know about the various methods of performing a single task. Two Methods to Retrieve List of Primary Keys and Foreign Keys of Database When Information Schema is used, we will not be able to discern between primary key and foreign key; we will have both the keys together. In the case of sys schema, we can query the data in our preferred way and can join this table to another table, which can retrieve additional data from the same. Get Last Running Query Based on SPID PID is returns sessions ID of the current user process. The acronym SPID comes from the name of its earlier version, Server Process ID. 2010 SELECT * FROM dual – Dual Equivalent Dual is a table that is created by Oracle together with data dictionary. It consists of exactly one column named “dummy”, and one record. The value of that record is X. You can check the content of the DUAL table using the following syntax. SELECT * FROM dual Identifying Statistics Used by Query Someone asked this question in my training class of query optimization and performance tuning.  “Can I know which statistics were used by my query?” 2011 SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 14 of 31 What are the basic functions for master, msdb, model, tempdb and resource databases? What is the Maximum Number of Index per Table? Explain Few of the New Features of SQL Server 2008 Management Studio Explain IntelliSense for Query Editing Explain MultiServer Query Explain Query Editor Regions Explain Object Explorer Enhancements Explain Activity Monitors SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 15 of 31 What is Service Broker? Where are SQL server Usernames and Passwords Stored in the SQL server? What is Policy Management? What is Database Mirroring? What are Sparse Columns? What does TOP Operator Do? What is CTE? What is MERGE Statement? What is Filtered Index? Which are the New Data Types Introduced in SQL SERVER 2008? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 16 of 31 What are the Advantages of Using CTE? How can we Rewrite Sub-Queries into Simple Select Statements or with Joins? What is CLR? What are Synonyms? What is LINQ? What are Isolation Levels? What is Use of EXCEPT Clause? What is XPath? What is NOLOCK? What is the Difference between Update Lock and Exclusive Lock? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 17 of 31 How will you Handle Error in SQL SERVER 2008? What is RAISEERROR? What is RAISEERROR? How to Rebuild the Master Database? What is the XML Datatype? What is Data Compression? What is Use of DBCC Commands? How to Copy the Tables, Schema and Views from one SQL Server to Another? How to Find Tables without Indexes? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 18 of 31 How to Copy Data from One Table to Another Table? What is Catalog Views? What is PIVOT and UNPIVOT? What is a Filestream? What is SQLCMD? What do you mean by TABLESAMPLE? What is ROW_NUMBER()? What are Ranking Functions? What is Change Data Capture (CDC) in SQL Server 2008? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 19 of 31 How can I Track the Changes or Identify the Latest Insert-Update-Delete from a Table? What is the CPU Pressure? How can I Get Data from a Database on Another Server? What is the Bookmark Lookup and RID Lookup? What is Difference between ROLLBACK IMMEDIATE and WITH NO_WAIT during ALTER DATABASE? What is Difference between GETDATE and SYSDATETIME in SQL Server 2008? How can I Check that whether Automatic Statistic Update is Enabled or not? How to Find Index Size for Each Index on Table? What is the Difference between Seek Predicate and Predicate? What are Basics of Policy Management? What are the Advantages of Policy Management? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 20 of 31 What are Policy Management Terms? What is the ‘FILLFACTOR’? Where in MS SQL Server is ’100’ equal to ‘0’? What are Points to Remember while Using the FILLFACTOR Argument? What is a ROLLUP Clause? What are Various Limitations of the Views? What is a Covered index? When I Delete any Data from a Table, does the SQL Server reduce the size of that table? What are Wait Types? How to Stop Log File Growing too Big? If any Stored Procedure is Encrypted, then can we see its definition in Activity Monitor? 2012 Example of Width Sensitive and Width Insensitive Collation Width Sensitive Collation: A single-byte character (half-width) represented as single-byte and the same character represented as a double-byte character (full-width) are when compared are not equal the collation is width sensitive. In this example we have one table with two columns. One column has a collation of width sensitive and the second column has a collation of width insensitive. Find Column Used in Stored Procedure – Search Stored Procedure for Column Name Very interesting conversation about how to find column used in a stored procedure. There are two different characters in the story and both are having a conversation about how to find column in the stored procedure. Here are two part story Part 1 | Part 2 SQL SERVER – 2012 Functions – FORMAT() and CONCAT() – An Interesting Usage Generate Script for Schema and Data – SQL in Sixty Seconds #021 – Video In simple words, in many cases the database move from one place to another place. It is not always possible to back up and restore databases. There are possibilities when only part of the database (with schema and data) has to be moved. In this video we learn that we can easily generate script for schema for data and move from one server to another one. INFORMATION_SCHEMA.COLUMNS and Value Character Maximum Length -1 I often see the value -1 in the CHARACTER_MAXIMUM_LENGTH column of INFORMATION_SCHEMA.COLUMNS table. I understand that the length of any column can be between 0 to large number but I do not get it when I see value in negative (i.e. -1). Any insight on this subject? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Can it be harmful to grant jackd realtime priority?

  - by SuperElectric

  I am apt-get installing Ardour, a sound mixing program, just to try it out. Installing Ardour also installs JACK, a dependency. As part of the JACK installation script, I get the following dialog: If you want to run jackd with realtime priorities, the user starting jackd needs realtime permissions. Accept this option to create the file /etc/security/limits.d/audio.conf, granting realtime priority and memlock privileges to the audio group. Running jackd with realtime priority minimizes latency, but may lead to complete system lock-ups by requesting all the available physical system memory, which is unacceptable in multi-user environments. Enable realtime process priority? I'm installing on my laptop, which never has multiple simultaneous users. I still have concerns: is JACK something that'll be used by the system itself to play any sound (i.e. will it replace ALSA)? If so, does that mean that if I enable realtime priority for JACK, I'll run a slight risk of freezing the machine whenever any sound is played? Or is JACK only going to be used by Ardour for now (until I install some other JACK-dependent program)? Thanks, -- Matt

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• Publish Static Content to WebLogic

  - by James Taylor

  Most people know WebLogic has a built in web server. Typically this is not an issue as you deploy java applications and WebLogic publishes to the web. But what if you just want to display a simple static HTML page. In WebLogic you can develop a simple web application to display static HTML content. In this example I used WLS 10.3.3. I want to display 2 files, an HTML file, and an xsd for reference. Create a directory of your choice, this is what I will call the document root. mkdir /u01/oracle/doc_root Copy the static files to this directory  In the document root directory created in step 1 create the directory WEB-INF mkdir WEB-INF In the WEB-INF directory create a file called web.xml with the following content <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/j2ee/dtds/web-app_2_3.dtd"> <web-app> </web-app> Login to the WebLogic console to deploy application Click on Deployments Click on Lock & Edit Click Install and set the path to the directory created in step 1 Leave default "Install this deployment as an application" and click Next Select a Managed Server to deploy to and click Next Accept the defaults and click Finish  Deployment completes successfully, now click the Activate Changes You should now see the application started in the deployments You can now access your static content via the following URL http://localhost:7001/doc_root/helloworld.html

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• Is 'Old-School' the Wrong Way to Describe Reliable Security?

  - by rickramsey

  source The Hotel Toronto apparently knows how to secure its environment. "Built directly into the bedrock in 1913, the vault features an incredible 4-foot thick steel door that weighs 40 tonnes, yet can nonetheless be moved with a single finger. During construction, the gargantuan door was hauled up Yonge Street from the harbour by a team of 18 horses. " 1913. Those were the days. Sysadmins had to be strong as bulls and willing to shovel horse maneur. At least nowadays you don't have to be that strong. And, if you happen to be trying to secure your Oracle Linux environment, you may be able to avoid the shoveling, as well. Provided you know the tricks of the trade contained in these two recently published articles. Tips for Hardening an Oracle Linux Server General strategies for hardening an Oracle Linux server. Oracle Linux comes "secure by default," but the actions you take when deploying the server can increase or decrease its security. How to minimize active services, lock down network services, and many other tips. By Ginny Henningsen, James Morris and Lenz Grimmer. Tips for Securing an Oracle Linux Environment System logging with logwatch and process accounting with psacct can help detect intrusion attempts and determine whether a system has been compromised. So can using the RPM package manager to verifying the integrity of installed software. These and other tools are described in this second article, which takes a wider perspective and gives you tips for securing your entire Oracle Linux environment. Also by the crack team of Ginny Henningsen, James Morris and Lenz Grimmer. - Rick Website Newsletter Facebook Twitter

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• Java - System design with distributed Queues and Locks

  - by sunny

  Looking for inputs to evaluate a design for a system (java) which would have a distributed queue serving several (but not too many) nodes. These nodes would process objects present in the distributed queue and on occasion require a distributed lock across the cluster on an arbitrary (distributed) data structures. These (distributed) data structures could potentially lie in a distributed cache. Eliminating Terracotta (DSO),Hazelcast and Akka what could be alternative choices. Currently considering zookeeper as a distributed locking mechanism. Since the recommendation of a znode is not to exceed the 1M size , the understanding is that zookeeper should not be used a distributed queue. And also from Netflix curator tech note 4. So should a distributed cache, say like memcached, or redis be used to emulate a distributed queue ? i.e. The distributed queue will be stored in the caches and will be locked cluster-wide via zookeeper. Are there potential pitfalls with this high-level approach. The objects don't need to be taken off the queue. The object will pass through a lifecycle which will determine its removal from the queue. There would be about 10k+ objects in a queue at a given time changing states and any node could service one stage of the object's lifecycle. (Although not strictly necessary .. i.e. one node could serve the entire lifecycle if that is more efficient.) Any suggestions/alternatives ? sidenote: new to zookeeper ; redis etc.

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