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• Running an app that requires an administrator account from a service

  - by Bergvall

  Is it possible to run handle.exe (from sysinternals) from a service (in windows7) without having to turn off UAC? The service is a custom c-app that needs to find out which process is locking a file it tries to access and handle.exe seems to be a good way to solve it but i can't get it to work with UAC turned on. This app runs all the time so i can't have a UAC prompt while its running but its fine if it shows up at startup. Handle.exe works fine from an admin commandprompt but fails when trying to run from a normal prompt. I call handle.exe from CreateProcess() and get the output from pipes. I guess there should be a way to solve this but i can't figure it out. Setting up the service to log in from an admin account does not seem to work.

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• Connection Timeout Linked Server

  - by Wade73

  I have created a linked server from one SQL Server 2005 to Another 2005. When I run an update query through the SQL Server Management Studio (SSMS), it runs in under a second. If I run the query through a asp webpage it times out. I ran SQL Profiler to see if I noticed anything as well as the Activity Monitor in SSMS and all I found was that a lock was being created (Wait type LOCK_M_U), but I can't find what is locking it. Any help would be appreciated. Wade

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• MySQL Full-text Search Workaround for innoDB tables

  - by Rob

  I'm designing an internal web application that uses MySQL as its backend database. The integrity of the data is crucial, so I am using the innoDB engine for its foreign key constraint features. I want to do a full-text search of one type of records, and that is not supported natively with innoDB tables. I'm not willing to move to MyISAM tables due to their lack of foreign key support and due to the fact that their locking is per table, not per row. Would it be bad practice to create a mirrored table of the records I need to search using the MyISAM engine and use that for the full-text search? This way I'm just searching a copy of the data and if anything happens to that data it's not as big of a deal because it can always be re-created. Or is this an awkward way of doing this that should be avoided? Thanks.

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• Python sqlite3 and concurrency

  - by RexE

  I have a Python program that uses the "threading" module. Once every second, my program starts a new thread that fetches some data from the web, and stores this data to my hard drive. I would like to use sqlite3 to store these results, but I can't get it to work. The issue seems to be about the following line: conn = sqlite3.connect("mydatabase.db") If I put this line of code inside each thread, I get an OperationalError telling me that the database file is locked. I guess this means that another thread has mydatabase.db open through a sqlite3 connection and has locked it. If I put this line of code in the main program and pass the connection object (conn) to each thread, I get a ProgrammingError, saying that SQLite objects created in a thread can only be used in that same thread. Previously I was storing all my results in CSV files, and did not have any of these file-locking issues. Hopefully this will be possible with sqlite. Any ideas?

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• How to generate distinct random numbers per distinct threads in .NET?

  - by mark

  Dear ladies and sirs. I have to generate 19 bit random numbers. However, there is a constraint - two threads may not generate the same random number when running certain code. The simplest solution is lock the entire code. However, I would like to know if there is a non locking solution. I thought, I can incorporate ManagedThreadId within the produced random numbers, but the ManagedThreadId documentation on the Internet mentions that it may span the whole Int32 range. Unmanaged thread id seems to be limited to 11 bits, still this leaves me with just 8 truly random bits. Are there any other ways? Somehow to utilize the Thread Local Storage, may be? Thanks.

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• How is Core Data detecting the conflicts, actually?

  - by brainfrog

  Apple says about -detectConflictsForObject: If on the next invocation of save: object has been modified in its persistent store, the save fails. This allows optimistic locking for unchanged objects. Conflict detection is always performed on changed or deleted objects. So what does this mean? If I simply modify an managed object and then save the context, there is always a conflict detection happening? Does this conflict detection simply compare the timestamps of the "records" to see if the "new" data is actually "old"? Is that a conflict?

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• Can ANYONE get _lockroot to work?

  - by webfac

  Hi Guys, I have the following code which ultimately loads a SWF into movieclip 'myloader' using a movie clip loader, code as follows: var myload:MovieClipLoader = new MovieClipLoader(); var listener:Object = new Object(); myload.addListener(listener); listener.onLoadStart = function(){ animcontainer.myloader._lockroot = true; trace("Started"); } listener.onLoadInit = function(){ animcontainer.myloader._lockroot = true; trace("finished and locked"); } listener.onLoadComplete = function(){ animcontainer.myloader._lockroot = true; } myload.loadClip(path, animcontainer.myloader); The swf I am loading has pause, rewind and play buttons that must be referencing _root as they work fine when played alone. Upon loading them into myloader they no longer work. Based on the above code surely the myloader clip should be locking as _root after the load is complete? I have Googled myself dry on this one, no luck. ANY help will be much appreciated, Thanks.

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• MySQL features I can rely on being available

  - by xrstf

  So I'm developing a PHP/MySQL based CMS which requires PHP 5.1 and MySQL 5.0 (with InnoDB support) at least. I'm now wondering what features of MySQL I can safely use without noticing one day that "Oh, well, that crappy hoster has disabled feature X, damn, now I'm screwed." So my question is, which of these features can become problematic (= can be disabled, require special configuration, require user privilege): transactions and FKs in InnoDB (of course unavailable to MyISAM) table locking (MyISAM and InnoDB) stored procedures I just want to know once and for all what's the minimal feature set I can expect from MySQL.

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• Can a thread call wait() on two locks at once in Java (6)

  - by Dr. Monkey

  I've just been messing around with threads in Java to get my head around them (it seems like the best way to do so) and now understand what's going on with synchronize, wait() and notify(). I'm curious about whether there's a way to wait() on two resources at once. I think the following won't quite do what I'm thinking of: synchronized(token1) { synchronized(token2) { token1.wait(); token2.wait(); //won't run until token1 is returned System.out.println("I got both tokens back"); } } In this (very contrived) case token2 will be held until token1 is returned, then token1 will be held until token2 is returned. The goal is to release both token1 and token2, then resume when both are available (note that moving the token1.wait() outside the inner synchronized loop is not what I'm getting at). A loop checking whether both are available might be more appropriate to achieve this behaviour (would this be getting near the idea of double-check locking?), but would use up extra resources - I'm not after a definitive solution since this is just to satisfy my curiosity.

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• SQL Server 2005 Transactions

  - by mcallec

  I have a long running stored proc (approx 30 mins) which is currently running within a transaction (isolation level snapshot). I've set the transaction to snapshot to avoid locking records preventing other processes from accessing the data. What I'm trying to do is write to and read from a status table, but although we're in a transaction I'd like to write to and read from the status table as if I'm not in a transaction. I need this so that other processes can read any updates to this table by my stored proc, and this stored proc can also read any inserts made by other processes. I realise that having my entire stored proc running within a transaction isn't recommended, but this has been done for other reasons and we need to stick with that approach. So my question is within a transaction, is it possible to execute a query or call a stored proc which effectively isn't enlisted in the transaction?

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• Exception for java Swing application?

  - by Rich Fluckiger

  For some reason this is locking up the java application. Did I handle the exception correctly? private void submitButtonActionPerformed(java.awt.event.ActionEvent evt) { double amount, interest,rateCalc, a, b, c, payment; int years, months; while (true){ try{ amount = Double.valueOf(loanAmount.getText()); interest = Double.valueOf(interestRate.getText()); years = Integer.valueOf(loanYears.getText()); rateCalc = (interest/12); months = (years*12); a = Math.pow((1+rateCalc),months); b = (a*rateCalc); c = (a-1); payment = (amount *(b/c)); monthlyPayment.setText("Mortgage Payment $ = " + payment); } catch (NumberFormatException nfe){ javax.swing.JOptionPane.showMessageDialog(null, "Please enter numbers and not letters"); return; } } } monthlyPayment returns to the java app.

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• How to know when a user console is locked or has logged "back into" windows

  - by Paul Kohler

  This is in regards to applications that run in the taskbar but should be applicable to standard apps, Winforms, WPF, etc. Question: I am after some method (preferably via managed code) to be notified when a user either has their screen "locked" while my app is running and/or know when they log back in. GMail Notifier does this sort of thing for example, if my PC is locked for a while when I log in again it shows a list of emails that arrived since locking the PC. I'm looking to replicate that kind of functionality. Does anyone have any ideas on how to accomplish this?

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• Advanced Registry Monitoring

  - by RyanTimmons91

  I'm attempting to create a small utility to watch for the creation (or modification) of a specific registry key, and to kill the process responsible for causing that registry modification. I have had success in watching the changes to the registry via a class called 'RegistryMonitor', however it does not give you any information on what process initiated the registry call, through some googling I found that a library called 'EasyHook' should be able to do what I want, but all the documentation states that its designed for a per-application hook. The program itself is a temporary security patch, until our vendors come out with an official security update. As best I can tell there isn't a way to do exactly what I want to accomplish from C#, which is the only language I can comfortable write, test and execute software in. Any help on this would be appreciated I'm considering watching the registry changes via the program I already have, then if the change is discovered (the pc is already infected) running RKill and locking down the PC to prevent the issue from getting any worse

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• Mysql with innodb and serializable transaction does not (always) lock rows

  - by Tobias G.

  Hello, I have a transaction with a SELECT and possible INSERT. For concurrency reasons, I added FOR UPDATE to the SELECT. To prevent phantom rows, I'm using the SERIALIZABLE transaction isolation level. This all works fine when there are any rows in the table, but not if the table is empty. When the table is empty, the SELECT FOR UPDATE does not do any (exclusive) locking and a concurrent thread/process can issue the same SELECT FOR UPDATE without being locked. CREATE TABLE t ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, display_order INT ) ENGINE = InnoDB; SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; START TRANSACTION; SELECT COALESCE(MAX(display_order), 0) + 1 from t FOR UPDATE; .. This concept works as expected with SQL Server, but not with MySQL. Any ideas on what I'm doing wrong? EDIT Adding an index on display_order does not change the behavior.

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• Grounded in Dublin

  - by Mike Dietrich

  Friday's hands-on workshop in the Oracle office in Dublin was quite good fun for everybody - except for Mick who has just recognized that his Ryanair flight back to Cork has been canceled (So I hope you've returned home well!) and me as my flights back to Munich via London City had been canceled as well. It's always good to have somebody in the workshop from Air Lingus so I've got hourly information what's going in in the Irish airspace (and now I know that the system dealing with such situations is an well prepared Oracle database which runs just like a switch watch - Thanks again for all your support!!! Was great to talk to you!!!). But to be honest, there are worse places to be grounded for a few days than Dublin. At least it gave me the chance to do something which I never had time enough before when visiting Oracle Ireland: a bit of sightseeing. When I've realized that nothing seems to move over the weekend I started organizing my travel back yesterday. It was no fun at all because there's no single system to book such a travel. Figuring out all possibilities and options going back to Munich was the first challange. Irish Ferries webpage was moaning with all the unexpected load (currently it's fully down). Hotel booking websites showed vacancies in Holyhead but didn't let me book. And calling them just reveiled that there are no rooms left. Haven't stayed overnight in a train station for quite a while ;-) The website of VirginTrains puzzled me with offering a seat at an enormous price for a train ride from Holyhead to London Euston (Thanks, Sir Richard Branson!) just to tell me after I booked a ticket that there are no seats left (but I traveled German railsways a few weeks ago from Düsseldorf to Frankfurt sitting on the floor as well). Eurostar's website let me choose tickets through the tunnel to tell me in the final step that the ticket cannot be confirmed as there are no seats left - but the next check again showed bookable seats - must be a database from some other vendor which has no proper row level locking ... hm ...?! Finally the TGV page for the speed train to Stuttgart and then the ICE to Munich was not allowing searches for quite a while - but ultimately ... after 4.5 hours of searching, waiting, sending credit card information again and again ... So if you have a few spare fingers please keep them crossed :-) And good luck to all my colleagues traveling back from the Exadata training in Berlin. As Mike Appleyard, my colleague from the UK presales team wrote: "Dublin and Berlin aren't too bad a place to get stuck... ;-)"

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• Michael Crump&rsquo;s notes for 70-563 PRO &ndash; Designing and Developing Windows Applications usi

  - by mbcrump

  TIME TO GO PRO! This is my notes for 70-563 PRO – Designing and Developing Windows Applications using .NET Framework 3.5 I created it using several resources (various certification web sites, msdn, official ms 70-548 book). The reason that I created this review is because a) I am taking the exam. b) MS did not create a book for this exam. Use the(MS 70-548)book. c) To make sure I am familiar with each before the exam. I hope that it provides a good start for your own notes. I hope that someone finds this useful. At least, it will give you a starting point of what to expect to know on the PRO exam. Also, for those wondering, the PRO exam does contains very little code. It is basically all theory. 1. Validation Controls – How to prevent users from entering invalid data on forms. (MaskedTextBox control and RegEx) 2. ServiceController – used to start and control the behavior of existing services. 3. User Feedback (know winforms Status Bar, Tool Tips, Color, Error Provider, Context-Sensitive and Accessibility) 4. Specific (derived) exceptions must be handled before general (base class) exceptions. By moving the exception handling for the base type Exception to after exception handling of ArgumentNullException, all ArgumentNullException thrown by the Helper method will be caught and logged correctly. 5. A heartbeat method is a method exposed by a Web service that allows external applications to check on the status of the service. 6. New users must master key tasks quickly. Giving these tasks context and appropriate detail will help. However, advanced users will demand quicker paths. Shortcuts, accelerators, or toolbar buttons will speed things along for the advanced user. 7. MSBuild uses project files to instruct the build engine what to build and how to build it. MSBuild project files are XML files that adhere to the MSBuild XML schema. The MSBuild project files contain complete file, build action, and dependency information for each individual projects. 8. Evaluating whether or not to fix a bug involves a triage process. You must identify the bug's impact, set the priority, categorize it, and assign a developer. Many times the person doing the triage work will assign the bug to a developer for further investigation. In fact, the workflow for the bug work item inside of Team System supports this step. Developers are often asked to assess the impact of a given bug. This assessment helps the person doing the triage make a decision on how to proceed. When assessing the impact of a bug, you should consider time and resources to fix it, bug risk, and impacts of the bug. 9. In large projects it is generally impossible and unfeasible to fix all bugs because of the impact on schedule and budget. 10. Code reviews should be conducted by a technical lead or a technical peer. 11. Testing Applications 12. WCF Services – application state 13. SQL Server 2005 / 2008 Express Edition – reliable storage of data / Microsoft SQL Server 3.5 Compact Database– used for client computers to retrieve and save data from a shared location. 14. SQL Server 2008 Compact Edition – used for minimum possible memory and can synchronize data with a corporate SQL Server 2008 Database. Supports offline user and minimum dependency on external components. 15. MDI and SDI Forms (specifically IsMDIContainer) 16. GUID – in the case of data warehousing, it is important to define unique keys. 17. Encrypting / Security Data 18. Understanding of Isolated Storage/Proper location to store items 19. LINQ to SQL 20. Multithreaded access 21. ADO.NET Entity Framework model 22. Marshal.ReleaseComObject 23. Common User Interface Layout (ComboBox, ListBox, Listview, MaskedTextBox, TextBox, RichTextBox, SplitContainer, TableLayoutPanel, TabControl) 24. DataSets Class - http://msdn.microsoft.com/en-us/library/system.data.dataset%28VS.71%29.aspx 25. SQL Server 2008 Reporting Services (SSRS) 26. SystemIcons.Shield (Vista UAC) 27. Leverging stored procedures to perform data manipulation for a database schema that can change. 28. DataContext 29. Microsoft Windows Installer Packages, ClickOnce(bootstrapping features), XCopy. 30. Client Application Services – will authenticate users by using the same data source as a ASP.NET web application. 31. SQL Server 2008 Caching 32. StringBuilder 33. Accessibility Guidelines for Windows Applications http://msdn.microsoft.com/en-us/library/ms228004.aspx 34. Logging erros 35. Testing performance related issues. 36. Role Based Security, GenericIdentity and GenericPrincipal 37. System.Net.CookieContainer will store session data for webapps (see isolated storage for winforms) 38. .NET CLR Profiler tool will identify objects that cause performance issues. 39. ADO.NET Synchronization (SyncGroup) 40. Globalization - CultureInfo 41. IDisposable Interface- reports on several questions relating to this. 42. Adding timestamps to determine whether data has changed or not. 43. Converting applications to .NET Framework 3.5 44. MicrosoftReportViewer 45. Composite Controls 46. Windows Vista KNOWN folders. 47. Microsoft Sync Framework 48. TypeConverter -Provides a unified way of converting types of values to other types, as well as for accessing standard values and sub properties. http://msdn.microsoft.com/en-us/library/system.componentmodel.typeconverter.aspx 49. Concurrency control mechanisms The main categories of concurrency control mechanisms are: Optimistic - Delay the checking of whether a transaction meets the isolation rules (e.g., serializability and recoverability) until its end, without blocking any of its (read, write) operations, and then abort a transaction, if the desired rules are violated. Pessimistic - Block operations of a transaction, if they may cause violation of the rules. Semi-optimistic - Block operations in some situations, and do not block in other situations, while delaying rules checking to transaction's end, as done with optimistic. 50. AutoResetEvent 51. Microsoft Messaging Queue (MSMQ) 4.0 52. Bulk imports 53. KeyDown event of controls 54. WPF UI components 55. UI process layer 56. GAC (installing, removing and queuing) 57. Use a local database cache to reduce the network bandwidth used by applications. 58. Sound can easily be annoying and distracting to users, so use it judiciously. Always give users the option to turn sound off. Because a user might have sound off, never convey important information through sound alone.

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• Create a Shortcut to Put Your Windows Computer into Hibernation

  - by Mysticgeek

  Putting your Windows computer into Hibernation Mode allows you to save power, and quickly access your desktop again when you need it. Here we show how to create a shortcut to put your PC in Hibernation Mode quickly. Note: Here we show how to create the shortcut in Windows 7 and add it to the Taskbar. But creating the shortcut should work in XP and Vista as well. Create Shortcut  Right-click an empty area on your desktop and select New \ Shortcut from the Context Menu. In the Create Shortcut window type or copy the following in the location field… C:\Windows\System32\rundll32.exe powrprof.dll, SetSuspendState 0,1,0 Now give the shortcut a name such as Hibernate Computer or whatever you want to call it. Now you have the shortcut on your desktop, but you might want to change the icon to something else. Change Shortcut Icon Right-click the shortcut icon and select Properties. Select the Shortcut Tab and click the Change Icon button. In the Look for icons in this file field copy and past the following then click OK. %SystemRoot%\system32\SHELL32.dll This brings up a list of included Windows icons you can choose from. Select whatever you want it to be. There are a couple of Power icons in the directory…click OK. Of course you can choose any icon you want, if you customize your icons just browse to the directory they are in. For more on selecting icons check out our article on how to customize your icons in Windows 7 or how to change a file type’s icon. Now you will see the icon in the Shortcut Properties window, click OK. Here we have a nice looking shortcut that you can use to put your machine into Hibernation. Or here we used a customized Star Trek icon just to make things more interesting… You can pin the shortcut to the Taskbar for easy access. Conclusion If Hibernation is not enabled on your Windows 7 system you can easily manage it. By creating a shortcut and pinning to the Taskbar, it allows you to put your machine into Hibernation Mode quick and easy. If you like to customize your desktop with unique icons check out our posts on a Sci-Fi icon pack or Video Game icon pack. Similar Articles Productive Geek Tips Create a Shortcut for Locking Your Computer Screen in Windows 7 or VistaCreate Shutdown / Restart / Lock Icons in Windows 7 or VistaHow To Manage Hibernate Mode in Windows 7Microsoft Releases Pre-SP1 Updates for Windows VistaCreate a Shortcut or Hotkey to Run CCleaner Silently TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 10 Superb Firefox Wallpapers OpenDNS Guide Google TV The iPod Revolution Ultimate Boot CD can help when disaster strikes Windows Firewall with Advanced Security – How To Guides

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• Rights Expiry Options in IRM 11g

  - by martin.abrahams

  Among the many enhancements in IRM 11g, we have introduced a couple of new rights expiry options that may be applied to any role. These options were supported in previous versions, but fell into the "advanced configuration" category. In 11g, the options can be applied simply by selecting a check-box in the properties of a role, as shown by the rather extreme example below, where the role allows access for just two minutes after they are sealed. The new options are: To define a role that expires automatically some period after it is assigned To define a role that evaluates expiry relative to the time that each document is sealed These options supplement the familiar options to allow open-ended access (limited by offline access and the ever-present option to revoke rights at any time) and the option to define time windows with specific start dates and end dates. The value of these options is easiest to illustrate with some publishing examples: You might define a role with a one year expiry to be assigned to users who purchase a one year subscription. For each individual user, the year would be calculated from the time that the role was assigned to them. You might define a role that allows documents to be accessed only for 24 hours from the time that they are published - perhaps as a preview mechanism designed to tempt users to sign up for a full subscription. Upon payment of a full fee, users can simply be reassigned a role that gives them greater access to exactly the same documents. In a corporate environment, you might use such roles for fixed term contractors or for workflows that involve information with a short lifespan, or perhaps as part of a compliance process that requires rights to be formally re-approved at intervals. Being role-based, the time constraints apply to any number of documents - including documents that have not yet been created. For example, a user with a one year subscription would have access to all documents published in the relevant classification during the year without any further configuration. Crucially, unlike other solutions, it is not the documents that expire, but the rights of particular users. Whereas some solutions make documents completely inaccessible for all users after expiry, Oracle IRM can allow some users to continue using documents while other users lose access. Equally crucially, a user whose rights have expired can always be granted fresh rights at any time - for example, because they renew their subscription or because a manager confirms that they still need the rights as part of a corporate compliance process. By applying expiry to rights rather than to documents, Oracle IRM avoids the risk of locking an organization out of its own information.

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• Reset All Internet Explorer 8 Settings to Fix Stability Problems

  - by Mysticgeek

  If you like to tweak and customize IE with Add-ons and changing settings, sometimes you may have problems with stability. To save time, you can reset all of the IE settings rather than trying to troubleshoot individual areas. Reset IE Settings To reset Internet Explorer Settings, click on Tools then Internet Options. When you reset the settings, you won’t lose personal settings like your homepage, search provider, passwords…etc. The Internet Options screen opens…click on the Advanced tab, then under Reset Internet Explorer settings click on the Reset button. You’ll need to verify that you want to reset all Internet Explorer Settings. If you choose to, you can delete all of your personal settings as well, but it shouldn’t be necessary to fix stability issues. The settings will start to reset, and when it’s finished close out of the message box. For the process to complete you’ll need to restart Internet Explorer. When it restarts you’ll be presented with the Welcome screen where you can go through the setup wizard again. After it’s complete, you should be back in business and can start using IE again. With the new enhancements and features available in Internet Explorer 8, sometimes too much tweaking can cause it to stop working. One area you could start with is troubleshooting IE 8 Add-ons. However, if you don’t want to waste time troubleshooting each potential issue, sometimes it’s just easier to reset things back to how they were originally. Similar Articles Productive Geek Tips Troubleshooting Internet Explorer on Vista Locking Up or Running SlowlyFix Internet Explorer Not Prompting to Choose Save Location in XPDealing With Windows Vista Explorer Screwing Up Auto-Detection of Folder TypesMysticgeek Blog: A Look at Internet Explorer 8 Beta 1 on Windows XPClean Up Past Notification Icons in Windows Vista TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow

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• SQL SERVER – Sharing your ETL Resources Across Applications with Ease

  - by pinaldave

  Frequently an organization will find that the same resources are used in multiple ETL applications, for example, the same database, general purpose processing logic, or file system locations.  Creating an easy way to reuse these resources across multiple applications would increase efficiency and reduce errors.  Moreover, not every ETL developer has the same skill set, and it is likely that one developer will be more adept at writing code while another is more comfortable configuring database connections.  Real productivity gains will come when these developers are able to work independently while still making their work available to others assigned to the same project.  These are the benefits of a centralized version control system. Of course, most version control systems could be used to store and serve files, but the real need is to store and serve entire ETL applications so that each developer’s ongoing work can immediately benefit from another developer’s completed work.  In other words, the version control system needs to be tightly integrated with the tools used to develop the ETL application. The following screen shot shows such a tool. Desktop ETL tool that tightly integrates with a central version control system Developers can checkout or commit entire projects or just a single artifact.  Each artifact may be managed independently so if you need to go back to an earlier version of one artifact, changes you may have made to other artifacts are not lost.  By being tightly integrated into the graphical environment used to create and edit the project artifacts, it is extremely easy and straight-forward to move your files to and from the version control system and there is no dependency on another vendor’s version control system.  The built in version control system is optimized for managing the artifacts of ETL applications. It is equally important that the version control system supports all of the actions one typically performs such as rollbacks, locking and unlocking of files, and the ability to resolve conflicts.  Note that this particular ETL tool also has the capability to switch back and forth between multiple version control systems. It also needs to be easy to determine the status of an artifact.  Not just that it has been committed or modified, but when and by whom.  Generally you must query the version control system for this information, but having it displayed within the development environment is more desirable. Who’s ETL tool works in this fashion?  Last month I mentioned the data integration solution offered by expressor software.  The version control features I described in this post are all available in their just released expressor 3.1 Standard Edition through the integration of their expressor Studio development environment with a centralized metadata repository and version control system. You can download their Studio application, which is free, or evaluate the full Standard Edition on your own hardware.  It may be worth your time. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• July, the 31 Days of SQL Server DMO’s – Day 24 (sys.dm_db_index_operational_stats)

  - by Tamarick Hill

  The sys.dm_db_index_operational_stats Dynamic Management Function returns information about the IO, locking, and access methods for the indexes that you currently have on your SQL Server Instance. This function takes four input parameters which are (1) database_id, (2) object_id, (3) index_id, and (4) partition_number. Let’s have a look at the results from this function against our AdventureWorks2012 database. This function returns a ton of columns, so not only will I not attempt to describe each of the columns, I wont even attempt to display all of them here. My query below will give you a subset of the columns returned from this function. SELECT database_id, object_id, index_id, partition_number, leaf_insert_count, leaf_delete_count, leaf_update_count, leaf_ghost_count, nonleaf_insert_count, nonleaf_delete_count, nonleaf_update_count, range_scan_count, forwarded_fetch_count, row_lock_count, row_lock_wait_count, page_lock_count, page_lock_wait_count, Index_lock_promotion_attempt_count, index_lock_promotion_count, page_compression_attempt_count, page_compression_success_count FROM sys.dm_db_index_operational_stats(db_id('AdventureWorks2012'), NULL, NULL, NULL) The first four columns in the result set represent the values that we passed in as our input parameters. If you use NULL’s as I did, then you will see results for every index on your system. I specified a database_id so my result set only shows those records pertaining to my AdventureWorks2012 database. The next columns in the result set provide you with information on how may inserts, deletes, or updates that have taken place on your leaf and nonleaf index levels. The nonleaf levels would refer to the intermediate and root index levels. In the middle of these you see a leaf_ghost_count column, which represents the number of records that have been logically deleted and marked as “ghosted”  and are waiting on the background ghost cleanup process to physically remove them. The range_scan_count column represents the number of range or table scans that have been performed against an index. The forwarded_fetch_count column represents the number of rows that were returned from a forwarding row pointer. The row_lock_count and row_lock_wait_count represent the number of row locks that have been requested for an index and the number of times SQL has had to wait on a row lock respectively. The page_lock_count and page_lock_wait_count represent the number of page locks that have been requested for an index and the number of times SQL has had to wait on a page lock respectively. The index_lock_promotion_attempt_count represents the number of times the database engine has attempted to promote a lock to the index level. The index_lock_promotion_count column displays how many times that index lock promotion was successful. Lastly the page_compression_attempt_count and page_compression_success_count represents how many times a page was attempted to be compressed and how many times the attempt was successful. As you can see there is a ton of information returned from this DMV. The DMV we reviewed on yesterday (sys.dm_db_index_usage_stats) provided you with good information on when and how indexes have been used, but this DMF takes an even deeper dive into these statistics. If you are interested in performing a very detailed analysis on the operational stats of your indexes, this is not only a good place to start, but more than likely the best place. For more information on this Dynamic Management Function, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms174281.aspx Follow me on Twitter @PrimeTimeDBA

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• Inverted schedctl usage in the JVM

  - by Dave

  The schedctl facility in Solaris allows a thread to request that the kernel defer involuntary preemption for a brief period. The mechanism is strictly advisory - the kernel can opt to ignore the request. Schedctl is typically used to bracket lock critical sections. That, in turn, can avoid convoying -- threads piling up on a critical section behind a preempted lock-holder -- and other lock-related performance pathologies. If you're interested see the man pages for schedctl_start() and schedctl_stop() and the schedctl.h include file. The implementation is very efficient. schedctl_start(), which asks that preemption be deferred, simply stores into a thread-specific structure -- the schedctl block -- that the kernel maps into user-space. Similarly, schedctl_stop() clears the flag set by schedctl_stop() and then checks a "preemption pending" flag in the block. Normally, this will be false, but if set schedctl_stop() will yield to politely grant the CPU to other threads. Note that you can't abuse this facility for long-term preemption avoidance as the deferral is brief. If your thread exceeds the grace period the kernel will preempt it and transiently degrade its effective scheduling priority. Further reading : US05937187 and various papers by Andy Tucker. We'll now switch topics to the implementation of the "synchronized" locking construct in the HotSpot JVM. If a lock is contended then on multiprocessor systems we'll spin briefly to try to avoid context switching. Context switching is wasted work and inflicts various cache and TLB penalties on the threads involved. If context switching were "free" then we'd never spin to avoid switching, but that's not the case. We use an adaptive spin-then-park strategy. One potentially undesirable outcome is that we can be preempted while spinning. When our spinning thread is finally rescheduled the lock may or may not be available. If not, we'll spin and then potentially park (block) again, thus suffering a 2nd context switch. Recall that the reason we spin is to avoid context switching. To avoid this scenario I've found it useful to enable schedctl to request deferral while spinning. But while spinning I've arranged for the code to periodically check or poll the "preemption pending" flag. If that's found set we simply abandon our spinning attempt and park immediately. This avoids the double context-switch scenario above. One annoyance is that the schedctl blocks for the threads in a given process are tightly packed on special pages mapped from kernel space into user-land. As such, writes to the schedctl blocks can cause false sharing on other adjacent blocks. Hopefully the kernel folks will make changes to avoid this by padding and aligning the blocks to ensure that one cache line underlies at most one schedctl block at any one time.

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• Why lock statements don't scale

  - by Alex.Davies

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

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• SQL SERVER – BI Quiz Hint – Performance Tuning Cubes – Hints

  - by pinaldave

  I earlier wrote about SQL BI Quiz over here and here. The details of the quiz is here: Working with huge data is very common when it is about Data Warehousing. It is necessary to create Cubes on the data to make it meaningful and consumable. There are cases when retrieving the data from cube takes lots of the time. Let us assume that your cube is returning you data very quickly. Suddenly on one day it is returning the data very slowly. What are the three things will you to diagnose this. After diagnose what you will do to resolve performance issue. Participate in my question over here I required BI Expert Jason Thomas to help with few hints to blog readers. He is one of the leading SSAS expert and writes a complicated subject in simple words. If queries were executing properly before but now take a long time to return the data, it means that there has been a change in the environment in which it is running. Some possible changes are listed below:-  1) Data factors:- Compare the data size then and now. Increase in data can result in different execution times. Poorly written queries as well as poor design will not start showing issues till the data grows. How to find it out? (Ans : SQL Server profiler and Perfmon Counters can be used for identifying the issues and performance  tuning the MDX queries)  2) Internal Factors:- Is some slow MDX query / multiple mdx queries running at the same time, which was not running when you had tested it before? Is there any locking happening due to proactive caching or processing operations? Are the measure group caches being cleared by processing operations? (Ans : Again, profiler and perfmon counters will help in finding it out. Load testing can be done using AS Performance Workbench (http://asperfwb.codeplex.com/) by running multiple queries at once)  3) External factors:- Is some other application competing for the same resources?  HINT : Read “Identifying and Resolving MDX Query Performance Bottlenecks in SQL Server 2005 Analysis Services” (http://sqlcat.com/whitepapers/archive/2007/12/16/identifying-and-resolving-mdx-query-performance-bottlenecks-in-sql-server-2005-analysis-services.aspx) Well, these are great tips. Now win big prizes by participate in my question over here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Concurrancy Problems and their Relationship with Isolation Level

  - by pinaldave

  Concurrency is simply put capability of the machine to support two or more transactions working with the same data at the same time. This usually comes up with data is being modified, as during the retrieval of the data this is not the issue. Most of the concurrency problems can be avoided by SQL Locks. There are four types of concurrency problems visible in the normal programming. 1)      Lost Update – This problem occurs when there are two transactions involved and both are unaware of each other. The transaction which occurs later overwrites the transactions created by the earlier update. 2)      Dirty Reads – This problem occurs when a transactions selects data that isn’t committed by another transaction leading to read the data which may not exists when transactions are over. Example: Transaction 1 changes the row. Transaction 2 changes the row. Transaction 1 rolls back the changes. Transaction 2 has selected the row which does not exist. 3)      Nonrepeatable Reads – This problem occurs when two SELECT statements of the same data results in different values because another transactions has updated the data between the two SELECT statements. Example: Transaction 1 selects a row, which is later on updated by Transaction 2. When Transaction A later on selects the row it gets different value. 4)      Phantom Reads – This problem occurs when UPDATE/DELETE is happening on one set of data and INSERT/UPDATE is happening on the same set of data leading inconsistent data in earlier transaction when both the transactions are over. Example: Transaction 1 is deleting 10 rows which are marked as deleting rows, during the same time Transaction 2 inserts row marked as deleted. When Transaction 1 is done deleting rows, there will be still rows marked to be deleted. When two or more transactions are updating the data, concurrency is the biggest issue. I commonly see people toying around with isolation level or locking hints (e.g. NOLOCK) etc, which can very well compromise your data integrity leading to much larger issue in future. Here is the quick mapping of the isolation level with concurrency problems: Isolation Dirty Reads Lost Update Nonrepeatable Reads Phantom Reads Read Uncommitted Yes Yes Yes Yes Read Committed No Yes Yes Yes Repeatable Read No No No Yes Snapshot No No No No Serializable No No No No I hope this 400 word small article gives some quick understanding on concurrency issues and their relation to isolation level. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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