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• PC monitors shut off and system hangs while playing 3D games, but sound continues - Diagnosis?

  - by Jon Schneider

  Two days ago, I started running into a problem with my Windows PC: The PC's two connected monitors simultaneously lose signal and go black (as though the PC had been powered off). The keyboard's Numlock, Capslock, and Scroll Lights will become "stuck" in their current positions, as though the PC is hung. (For example, the Numlock light on the keyboard remains lit regardless of me pressing the Numlock key repeatedly.) No keyboard input does anything. (Ctrl+Alt+Del, Ctrl+Shift+Esc, Ctrl+C, etc.) However -- Whatever sound/music the PC was playing continues to play, and the PC's fans continue running, so the PC hasn't powered itself off or rebooted itself. Opening up the case, the graphics card is pretty hot to the touch. I had this happen 3 times in one evening. In all cases, I was playing a game with 3D graphics when the problem occurred (Torchlight, Minecraft, Magic: The Gathering 2012, Avadon: The Black Fortress demo). I have yet to have the problem happen when I'm not playing a game. This system has been running stable for about 2.5 years prior to this. I didn't make any changes to the system prior to the problem starting to occur. System specs: OS: Windows 7 64-bit Processor: Intel Core 2 Duo E7200 Wolfdale 2.53GHz Video Card: XFX GeForce 9800 GT 512 MB Motherboard: Foxconn P45A-S LGA 775 Intel ATX RAM: Corsair 4 GB (2x 2GB) DDR2-800 (PC2 6400) Full specs: New PC 2008 Troubleshooting tried so far (the problem occurred again after taking each of these steps, one at a time): Updated the video drivers with the latest drivers from NVidia's site. Opened up the case and cleaned out the video card and processor fans (both were pretty dirty). Installed and ran temperature monitor software. The processor idles at about 50 degrees C, and goes up to about 63 degrees C while playing a game (seems on the warm side, but not excessively so?). The software wasn't able to report the temperature of the GPU -- not sure this particular GPU supports software temperature readout? My initial diagnosis is that maybe the GPU is on its last legs (given that it seems to be running pretty hot, and the problem only occurs while playing 3D games). Does this seem likely? Or is it likely that this problem is caused by the processor, RAM, or motherboard? Or could this be a software issue of some kind? Thanks for any advice!

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• batch file infinite loop when parsing file

  - by Bart

  Okay, this should be a really simple task but its proving to be more complicated than I think it should be. I'm clearly doing something wrong, and would like someone else's input. What I would like to do is parse through a file containing paths to directories and set permissions on those directories. An example line of the input file. There are several lines, all formatted the same way, with a different path to a directory. E:\stuff\Things\something else (X)\ (The file in question is generated under Cygwin using find to list all directories with "(X)" in the name. The file is then passed through unix2win to make it windows compatible. I've also tried manually creating the input file from within windows to rule out the file's creation method as the problem.) Here's where I'm stuck... I wrote the following quick and dirty batch file in Windows XP and it worked without any issues at all, but it will not work in server 2k8. Batch file code to run through the file and set permissions: FOR /F "tokens=*" %%A IN (dirlist.txt) DO echo y| cacls "%%A" /T /C /G "Domain Admins":f "Some Group":f "some-security-group":f What this is SUPPOSED to do (and does in XP) is loop through the specified file (dirlist.txt) and run cacls.exe on each directory it pulls from the file. The "echo y|" is in there to automagically confirm when cacls helpfully asks "are you sure?" for every directory in the list. Unfortunately, however, what it DOES is fall into an infinite loop. I've tried surrounding everything after "DO" with quotes, which prevents the endless loop but confuses cacls so it throws an error. Interestingly, I've tried running the code from after "DO" manually (obviously replacing the variable with the full path, copied straight from the file) at a command prompt and it runs as expected. I don't think it's the file or the loop, as adding quotes to the command to be executed prevents the loop from continuing past where it's supposed to... I really have no idea at this point. Any help would be appreciated. I have a feeling it's going to be something increadibly stupid... but I'm pulling my hair out so I thought I'd ask.

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• Switch flooding when bonding interfaces in Linux

  - by John Philips

  +--------+ | Host A | +----+---+ | eth0 (AA:AA:AA:AA:AA:AA) | | +----+-----+ | Switch 1 | (layer2/3) +----+-----+ | +----+-----+ | Switch 2 | +----+-----+ | +----------+----------+ +-------------------------+ Switch 3 +-------------------------+ | +----+-----------+----+ | | | | | | | | | | eth0 (B0:B0:B0:B0:B0:B0) | | eth4 (B4:B4:B4:B4:B4:B4) | | +----+-----------+----+ | | | Host B | | | +----+-----------+----+ | | eth1 (B1:B1:B1:B1:B1:B1) | | eth5 (B5:B5:B5:B5:B5:B5) | | | | | | | | | +------------------------------+ +------------------------------+ Topology overview Host A has a single NIC. Host B has four NICs which are bonded using the balance-alb mode. Both hosts run RHEL 6.0, and both are on the same IPv4 subnet. Traffic analysis Host A is sending data to Host B using some SQL database application. Traffic from Host A to Host B: The source int/MAC is eth0/AA:AA:AA:AA:AA:AA, the destination int/MAC is eth5/B5:B5:B5:B5:B5:B5. Traffic from Host B to Host A: The source int/MAC is eth0/B0:B0:B0:B0:B0:B0, the destination int/MAC is eth0/AA:AA:AA:AA:AA:AA. Once the TCP connection has been established, Host B sends no further frames out eth5. The MAC address of eth5 expires from the bridge tables of both Switch 1 & Switch 2. Switch 1 continues to receive frames from Host A which are destined for B5:B5:B5:B5:B5:B5. Because Switch 1 and Switch 2 no longer have bridge table entries for B5:B5:B5:B5:B5:B5, they flood the frames out all ports on the same VLAN (except for the one it came in on, of course). Reproduce If you ping Host B from a workstation which is connected to either Switch 1 or 2, B5:B5:B5:B5:B5:B5 re-enters the bridge tables and the flooding stops. After five minutes (the default bridge table timeout), flooding resumes. Question It is clear that on Host B, frames arrive on eth5 and exit out eth0. This seems ok as that's what the Linux bonding algorithm is designed to do - balance incoming and outgoing traffic. But since the switch stops receiving frames with the source MAC of eth5, it gets timed out of the bridge table, resulting in flooding. Is this normal? Why aren't any more frames originating from eth5? Is it because there is simply no other traffic going on (the only connection is a single large data transfer from Host A)? I've researched this for a long time and haven't found an answer. Documentation states that no switch changes are necessary when using mode 6 of the Linux interface bonding (balance-alb). Is this behavior occurring because Host B doesn't send any further packets out of eth5, whereas in normal circumstances it's expected that it would? One solution is to setup a cron job which pings Host B to keep the bridge table entries from timing out, but that seems like a dirty hack.

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• Vista stuck at "Shutting down..." screen. Any way to get verbose logging?

  - by CapBBeard

  Hi all, My home machine has been running fine for about 3 years, no problems at all. Within the last couple of weeks it's had real trouble trying to shut down. It'll get so far and then just sit there at the "Shutting down..." screen for hours. I've left it overnight, I've tried in safe mode, all to no avail. These days, I just wait for the disk activity to finish up and then hold the power button to turn it off. Feels dirty as, especially because there's a RAID involved! The hardware itself is in pretty good shape and of decent spec; Core 2 Quad, 4GB RAM, 1TB RAID 1+0, so it's not quite like a 7 year old PC coming to end of life! In the last month, hardware hasn't changed except for a new monitor. Admittedly I haven't tried unplugging the monitor but I've never heard of that preventing a shutdown. I might give it a whirl later I guess, as a last resort. I've uninstalled old apps, done updates, checked the event log, looked in device manager, uninstalled all non-present devices, disabled various non-critical devices (imaging, audio etc), unplugged peripherals, stopped non-essential services, unplugged the network, disabled the network adapter entirely, ran chkdsk, verified my RAID, the list goes on. But not a single lead. I'm pretty stumped. It could be hardware, but I have no other evidence to suggest so; when the PC is running, it runs fine. Temperatures are good, gaming is smooth as always, disk performance is fine. Event log even makes it look like the shutdown was completed (gets to the point where the event log service stops). In fact, the PC doesn't appear to realise that I cut the power to it. So my question is, does anyone know if there is a way I can get some verbose output (or a log) from shutdown to give me some idea of what is causing the issue? I'm guessing it's stuck unloading some app/driver but it would be good to get some specifics! Unless anyone has any other ideas? I suspect a reinstall would resolve the issue, however I'm looking to get a new PC built in the next month or so, and the reinstall is going to be quite a big job so I'd rather just wait until then if it comes to that. Would still be nice to get this sorted in the mean time though. Cheers!

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• Installing and configuring Zend Framework 2 server-wide [Ubuntu] and test driving ZendSkeletonApplication

  - by kinologik

  I'm trying to have ZF2 installed for all my subdomains at once (Ubuntu 12.04). ZF2 just launched its first stable version, so I wanted to install it on my development server and finally get my hands dirty with it. I downloaded ZF2 and unzipped the files in /var/ZF2/ (which now contains Zend/[all components]). I then edited /etc/php5/apache2/php.ini and added the path to the ZF2 files: include_path = ".:/var/ZF2" I then downloaded the ZendSkeletonApplication and unzipped it in /var/www/skeleton. I know it is suggested to composer.phar to install ZF2 application, but: I don't want to make a local installation of ZF2... I want to make a server-wide installation be able to use my Zend components on all my domains/subdomains on my development server. Before using any automatic installation process, I'd really like to understand that process by doing it manually at first. Obviously, something goes wrong when I fire ZendSkeletonApplication, and I get the following when hit the following URL: http://www.myDevServer.com/skeleton/public/ Fatal error: Uncaught exception 'RuntimeException' with message 'Unable to load ZF2. Run `php composer.phar install` or define a ZF2_PATH environment variable.' in /var/www/skeleton/init_autoloader.php:48 Stack trace: #0 /var/www/skeleton/public/index.php(9): include() #1 {main} thrown in /var/www/skeleton/init_autoloader.php on line 48 I have skimmed through the docs, tutorials and the like, but there are no straight forward answer to this kind of configuration. In the official doc, in the (very short) installation chapter, I see a reference to adding an include path in PHP. But no example... http://zf2.readthedocs.org/en/latest/ref/installation.html Once you have a copy of Zend Framework available, your application needs to be able to access the framework classes found in the library folder. Though there are several ways to achieve this, your PHP include_path needs to contain the path to Zend Framework’s library. But then, when I get to the "Getting Started" chapter, it's all composer.phar and nothing else... http://zf2.readthedocs.org/en/latest/user-guide/skeleton-application.html I'm no sysAdmin, just a Zend enthusiast. I'm pretty sure this PEBKAC problem might be obvious for those who already got in ZF2 previous betas. Thanks for helping my out. EDIT: Problem was resolved, thanks to Daniel M. Just setting up ZF2_PATH in httpd.conf was all that was needed. SetEnv ZF2_PATH /var/ZF2 I also removed the include_path reference in php.ini and everything works just fine. So I have no idea why Zend suggested to include it there in their official docs.

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• How to disable or tune filesystem cache sharing for OpenVZ?

  - by gertvdijk

  For OpenVZ, an example of container-based virtualization, it seems that host and all guests are sharing the filesystem cache. This sounds paradoxical when talking about virtualization, but this is actually a feature of OpenVZ. It makes sense too. Because only one kernel is running, it's possible to benefit from sharing the same pages of filesystem cache in memory. And while it sounds beneficial, I think a set up here actually suffers in performance from it. Here's why I think why: my machines aren't actually sharing any files on disk so I can't benefit from this feature in OpenVZ. Several OpenVZ machines are running MySQL with MyISAM tables. MyISAM relies on the system's filesystem cache for caching of data files, unlike InnoDB's buffer pool. Also some virtual machines are known to do heavy and large I/O operations on the same filesystem in the host. For example, when running cat *.MYD > /dev/null on some large database in one machine, I saw the filesystem cache lowering in another, monitored by htop. This essentially flushes all the useful filesystem cache in guests (FIFO) and so it flushes the MySQL caches in the guests. Now users are complaining that MySQL is very slow. And it is. Some simple SELECT queries take several seconds on times disk I/O is heavily used by other machines. So, simply put: Is there a way to avoid filesystem cache being wiped out by other virtual machines in container-based virtualization? Some thoughts: Choosing algorithm for flushing filesystem cache in the kernel. (possible? how?) Reserving a certain amount of pages for a single VM. (seems no option for filesystem cache type of pages that reading man vzctl) Will running MySQL on another filesystem get me anywhere? If not, I think my alternatives are: Use KVM for MySQL-MyISAM running VMs. KVM actually assigns memory to the VM and does not allow swapping out caches unless using a balloon driver. Move to InnoDB and tune the buffer pools, dirty pages, etc. This is now considered to be 'nice to have' on the long-term as not everyone responsible for administration of the system understands InnoDB. more suggestions welcome. System software: Proxmox (now 1.9, could be upgraded to 2.x). One big LV assigned for the VMs.

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• 8 Mac System Features You Can Access in Recovery Mode

  - by Chris Hoffman

  A Mac’s Recovery Mode is for more than just reinstalling Mac OS X. You’ll find many other useful troubleshooting utilities here — you can use these even if your Mac can’t boot normally. To access Recovery Mode, restart your Mac and press and hold the Command + R keys during the boot-up process. This is one of several hidden startup options on a Mac. Reinstall Mac OS X Most people know Recovery Mode as the place you go to reinstall OS X on your Mac. Recovery Mode will download the OS X installer files from teh Intenret if you don’t have them locally, so they don’t take up space on your disk and you’ll never have to hunt for an opearign system disc. Better yet, it will download up-to-date installation files so you don’t have to spend hours installing operating system updates later. Microsoft could learn a lot from Apple here. Restore From a Time Machine Backup Instead of reinstalling OS X, you can choose to restore your Mac from a time machine backup. This is like restoring a system image on another operating system. You’ll need an external disk containing a backup image created on the current computer to do this. Browse the Web The Get Help Online link opens the Safari web browser to Apple’s documentation site. It’s not limited to Apple’s website, though — you can navigate to any website you like. This feature allows you to access and use a browser on your Mac even if it isn’t booting properly. It’s ideal for looking up troubleshooting information. Manage Your Disks The Disk Utility option opens the same Disk Utility you can access from within Mac OS X. It allows you to partition disks, format them, scan disks for problems, wipe drives, and set up drives in a RAID configuration. If you need to edit partitions from outside your operating system, you can just boot into the recovery environment — you don’t have to download a special partitioning tool and boot into it. Choose the Default Startup Disk Click the Apple menu on the bar at the top of your screen and select Startup Disk to access the Choose Startup Disk tool. Use this tool to choose your computer’s default startup disk and reboot into another operating system. For example, it’s useful if you have Windows installed alongside Mac OS X with Boot Camp. Add or Remove an EFI Firmware Password You can also add a firmware password to your Mac. This works like a BIOS password or UEFI password on a Windows or Linux PC. Click the Utilities menu on the bar at the top of your screen and select Firmware Password Utility to open this tool. Use the tool to turn on a firmware password, which will prevent your computer from starting up from a different hard disk, CD, DVD, or USB drive without the password you provide. This prevents people form booting up your Mac with an unauthorized operating system. If you’ve already enabled a firmware password, you can remove it from here. Use Network Tools to Troubleshoot Your Connection Select Utilities > Network Utility to open a network diagnostic tool. This utility provides a graphical way to view your network connection information. You can also use the netstat, ping, lookup, traceroute, whois, finger, and port scan utilities from here. These can be helpful to troubleshoot Internet connection problems. For example, the ping command can demonstrate whether you can communicate with a remote host and show you if you’re experiencing packet loss, while the traceroute command can show you where a connection is failing if you can’t connect to a remote server. Open a Terminal If you’d like to get your hands dirty, you can select Utilities > Terminal to open a terminal from here. This terminal allows you to do more advanced troubleshooting. Mac OS X uses the bash shell, just as typical Linux distributions do. Most people will just need to use the Reinstall Mac OS X option here, but there are many other tools you can benefit from. If the Recovery Mode files on your Mac are damaged or unavailable, your Mac will automatically download them from Apple so you can use the full recovery environment.

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• Find only physical network adapters with WMI Win32_NetworkAdapter class

  - by Mladen Prajdic

  WMI is Windows Management Instrumentation infrastructure for managing data and machines. We can access it by using WQL (WMI querying language or SQL for WMI). One thing to remember from the WQL link is that it doesn't support ORDER BY. This means that when you do SELECT * FROM wmiObject, the returned order of the objects is not guaranteed. It can return adapters in different order based on logged-in user, permissions of that user, etc… This is not documented anywhere that I've looked and is derived just from my observations. To get network adapters we have to query the Win32_NetworkAdapter class. This returns us all network adapters that windows detect, real and virtual ones, however it only supplies IPv4 data. I've tried various methods of combining properties that are common on all systems since Windows XP. The first thing to do to remove all virtual adapters (like tunneling, WAN miniports, etc…) created by Microsoft. We do this by adding WHERE Manufacturer!='Microsoft' to our WMI query. This greatly narrows the number of adapters we have to work with. Just on my machine it went from 20 adapters to 5. What was left were one real physical Realtek LAN adapter, 2 virtual adapters installed by VMware and 2 virtual adapters installed by VirtualBox. If you read the Win32_NetworkAdapter help page you'd notice that there's an AdapterType that enumerates various adapter types like LAN or Wireless and AdapterTypeID that gives you the same information as AdapterType only in integer form. The dirty little secret is that these 2 properties don't work. They are both hardcoded, AdapterTypeID to "0" and AdapterType to "Ethernet 802.3". The only exceptions I've seen so far are adapters that have no values at all for the two properties, "RAS Async Adapter" that has values of AdapterType = "Wide Area Network" and AdapterTypeID = "3" and various tunneling adapters that have values of AdapterType = "Tunnel" and AdapterTypeID = "15". In the help docs there isn't even a value for 15. So this property was of no help. Next property to give hope is NetConnectionId. This is the name of the network connection as it appears in the Control Panel -> Network Connections. Problem is this value is also localized into various languages and can have different names for different connection. So both of these properties don't help and we haven't even started talking about eliminating virtual adapters. Same as the previous one this property was also of no help. Next two properties I checked were ConfigManagerErrorCode and NetConnectionStatus in hopes of finding disabled and disconnected adapters. If an adapter is enabled but disconnected the ConfigManagerErrorCode = 0 with different NetConnectionStatus. If the adapter is disabled it reports ConfigManagerErrorCode = 22. This looked like a win by using (ConfigManagerErrorCode=0 or ConfigManagerErrorCode=22) in our condition. This way we get enabled (connected and disconnected adapters). Problem with all of the above properties is that none of them filter out the virtual adapters installed by virtualization software like VMware and VirtualBox. The last property to give hope is PNPDeviceID. There's an interesting observation about physical and virtual adapters with this property. Every virtual adapter PNPDeviceID starts with "ROOT\". Even VMware and VirtualBox ones. There were some really, really old physical adapters that had PNPDeviceID starting with "ROOT\" but those were in pre win XP era AFAIK. Since my minimum system to check was Windows XP SP2 I didn't have to worry about those. The only virtual adapter I've seen to not have PNPDeviceID start with "ROOT\" is the RAS Async Adapter for Wide Area Network. But because it is made by Microsoft we've eliminated it with the first condition for the manufacturer. Using the PNPDeviceID has so far proven to be really effective and I've tested it on over 20 different computers of various configurations from Windows XP laptops with wireless and bluetooth cards to virtualized Windows 2008 R2 servers. So far it always worked as expected. I will appreciate you letting me know if you find a configuration where it doesn't work. Let's see some C# code how to do this: ManagementObjectSearcher mos = null;// WHERE Manufacturer!='Microsoft' removes all of the // Microsoft provided virtual adapters like tunneling, miniports, and Wide Area Network adapters.mos = new ManagementObjectSearcher(@"SELECT * FROM Win32_NetworkAdapter WHERE Manufacturer != 'Microsoft'");// Trying the ConfigManagerErrorCode and NetConnectionStatus variations // proved to still not be enough and it returns adapters installed by // the virtualization software like VMWare and VirtualBox// ConfigManagerErrorCode = 0 -> Device is working properly. This covers enabled and/or disconnected devices// ConfigManagerErrorCode = 22 AND NetConnectionStatus = 0 -> Device is disabled and Disconnected. // Some virtual devices report ConfigManagerErrorCode = 22 (disabled) and some other NetConnectionStatus than 0mos = new ManagementObjectSearcher(@"SELECT * FROM Win32_NetworkAdapter WHERE Manufacturer != 'Microsoft' AND (ConfigManagerErrorCode = 0 OR (ConfigManagerErrorCode = 22 AND NetConnectionStatus = 0))");// Final solution with filtering on the Manufacturer and PNPDeviceID not starting with "ROOT\"// Physical devices have PNPDeviceID starting with "PCI\" or something else besides "ROOT\"mos = new ManagementObjectSearcher(@"SELECT * FROM Win32_NetworkAdapter WHERE Manufacturer != 'Microsoft' AND NOT PNPDeviceID LIKE 'ROOT\\%'");// Get the physical adapters and sort them by their index. // This is needed because they're not sorted by defaultIList<ManagementObject> managementObjectList = mos.Get() .Cast<ManagementObject>() .OrderBy(p => Convert.ToUInt32(p.Properties["Index"].Value)) .ToList();// Let's just show all the properties for all physical adapters.foreach (ManagementObject mo in managementObjectList){ foreach (PropertyData pd in mo.Properties) Console.WriteLine(pd.Name + ": " + (pd.Value ?? "N/A"));}   That's it. Hope this helps you in some way.

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• How to structure game states in an entity/component-based system

  - by Eva

  I'm making a game designed with the entity-component paradigm that uses systems to communicate between components as explained here. I've reached the point in my development that I need to add game states (such as paused, playing, level start, round start, game over, etc.), but I'm not sure how to do it with my framework. I've looked at this code example on game states which everyone seems to reference, but I don't think it fits with my framework. It seems to have each state handling its own drawing and updating. My framework has a SystemManager that handles all the updating using systems. For example, here's my RenderingSystem class: public class RenderingSystem extends GameSystem { private GameView gameView_; /** * Constructor * Creates a new RenderingSystem. * @param gameManager The game manager. Used to get the game components. */ public RenderingSystem(GameManager gameManager) { super(gameManager); } /** * Method: registerGameView * Registers gameView into the RenderingSystem. * @param gameView The game view registered. */ public void registerGameView(GameView gameView) { gameView_ = gameView; } /** * Method: triggerRender * Adds a repaint call to the event queue for the dirty rectangle. */ public void triggerRender() { Rectangle dirtyRect = new Rectangle(); for (GameObject object : getRenderableObjects()) { GraphicsComponent graphicsComponent = object.getComponent(GraphicsComponent.class); dirtyRect.add(graphicsComponent.getDirtyRect()); } gameView_.repaint(dirtyRect); } /** * Method: renderGameView * Renders the game objects onto the game view. * @param g The graphics object that draws the game objects. */ public void renderGameView(Graphics g) { for (GameObject object : getRenderableObjects()) { GraphicsComponent graphicsComponent = object.getComponent(GraphicsComponent.class); if (!graphicsComponent.isVisible()) continue; GraphicsComponent.Shape shape = graphicsComponent.getShape(); BoundsComponent boundsComponent = object.getComponent(BoundsComponent.class); Rectangle bounds = boundsComponent.getBounds(); g.setColor(graphicsComponent.getColor()); if (shape == GraphicsComponent.Shape.RECTANGULAR) { g.fill3DRect(bounds.x, bounds.y, bounds.width, bounds.height, true); } else if (shape == GraphicsComponent.Shape.CIRCULAR) { g.fillOval(bounds.x, bounds.y, bounds.width, bounds.height); } } } /** * Method: getRenderableObjects * @return The renderable game objects. */ private HashSet<GameObject> getRenderableObjects() { return gameManager.getGameObjectManager().getRelevantObjects( getClass()); } } Also all the updating in my game is event-driven. I don't have a loop like theirs that simply updates everything at the same time. I like my framework because it makes it easy to add new GameObjects, but doesn't have the problems some component-based designs encounter when communicating between components. I would hate to chuck it just to get pause to work. Is there a way I can add game states to my game without removing the entity-component design? Does the game state example actually fit my framework, and I'm just missing something? EDIT: I might not have explained my framework well enough. My components are just data. If I was coding in C++, they'd probably be structs. Here's an example of one: public class BoundsComponent implements GameComponent { /** * The position of the game object. */ private Point pos_; /** * The size of the game object. */ private Dimension size_; /** * Constructor * Creates a new BoundsComponent for a game object with initial position * initialPos and initial size initialSize. The position and size combine * to make up the bounds. * @param initialPos The initial position of the game object. * @param initialSize The initial size of the game object. */ public BoundsComponent(Point initialPos, Dimension initialSize) { pos_ = initialPos; size_ = initialSize; } /** * Method: getBounds * @return The bounds of the game object. */ public Rectangle getBounds() { return new Rectangle(pos_, size_); } /** * Method: setPos * Sets the position of the game object to newPos. * @param newPos The value to which the position of the game object is * set. */ public void setPos(Point newPos) { pos_ = newPos; } } My components do not communicate with each other. Systems handle inter-component communication. My systems also do not communicate with each other. They have separate functionality and can easily be kept separate. The MovementSystem doesn't need to know what the RenderingSystem is rendering to move the game objects correctly; it just need to set the right values on the components, so that when the RenderingSystem renders the game objects, it has accurate data. The game state could not be a system, because it needs to interact with the systems rather than the components. It's not setting data; it's determining which functions need to be called. A GameStateComponent wouldn't make sense because all the game objects share one game state. Components are what make up objects and each one is different for each different object. For example, the game objects cannot have the same bounds. They can have overlapping bounds, but if they share a BoundsComponent, they're really the same object. Hopefully, this explanation makes my framework less confusing.

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• To Bit or Not To Bit

  - by Johnm

  'Twas a long day of troubleshooting and firefighting and now, with most of the office vacant, you face a blank scripting window to create a new table in his database. Many questions circle your mind like dirty water gurgling down the bathtub drain: "How normalized should this table be?", "Should I use an identity column?", "NVarchar or Varchar?", "Should this column be NULLABLE?", "I wonder what apple blue cheese bacon cheesecake tastes like?" Well, there are times when the mind goes it's own direction. A Bit About Bit At some point during your table creation efforts you will encounter the decision of whether to use the bit data type for a column. The bit data type is an integer data type that recognizes only the values of 1, 0 and NULL as valid. This data type is often utilized to store yes/no or true/false values. An example of its use would be a column called [IsGasoline] which would be intended to contain the value of 1 if the row's subject (a car) had a gasoline engine and a 0 if the subject did not have a gasoline engine. The bit data type can even be found in some of the system tables of SQL Server. For example, the sysssispackages table in the msdb database which contains SQL Server Integration Services Package information for the packages stored in SQL Server. This table contains a column called [IsEncrypted]. A value of 1 indicates that the package has been encrypted while the value of 0 indicates that it is not. I have learned that the most effective way to disperse the crowd that surrounds the office coffee machine is to engage into SQL Server debates. The bit data type has been one of the most reoccurring, as well as the most enjoyable, of these topics. It contains a practical side and a philosophical side. Practical Consideration This data type certainly has its place and is a valuable option for database design; but it is often used in situations where the answer is really not a pure true/false response. In addition, true/false values are not very informative or scalable. Let's use the previously noted [IsGasoline] column for illustration. While on the surface it appears to be a rather simple question when evaluating a car: "Does the car have a gasoline engine?" If the person entering data is entering a row for a Jeep Liberty, the response would be a 1 since it has a gasoline engine. If the person is entering data is entering a row for a Chevrolet Volt, the response would be a 0 since it is an electric engine. What happens when a person is entering a row for the gasoline/electric hybrid Toyota Prius? Would one person's conclusion be consistent with another person's conclusion? The argument could be made that the current intent for the database is to be used only for pure gasoline and pure electric engines; but this is where the scalability issue comes into play. With the use of a bit data type a database modification and data conversion would be required if the business decided to take on hybrid engines. Whereas, alternatively, if the int data type were used as a foreign key to a reference table containing the engine type options, the change to include the hybrid option would only require an entry into the reference table. Philosophical Consideration Since the bit data type is often used for true/false or yes/no data (also called Boolean) it presents a philosophical conundrum of what to do about the allowance of the NULL value. The inclusion of NULL in a true/false or yes/no response simply violates the logical principle of bivalence which states that "every proposition is either true or false". If NULL is not true, then it must be false. The mathematical laws of Boolean logic support this concept by stating that the only valid values of this scenario are 1 and 0. There is another way to look at this conundrum: NULL is also considered to be the absence of a response. In other words, it is the equivalent to "undecided". Anyone who watches the news can tell you that polls always include an "undecided" option. This could be considered a valid option in the world of yes/no/dunno. Through out all of these considerations I have discovered one absolute certainty: When you have found a person, or group of persons, who are willing to entertain a philosophical debate of the bit data type, you have found some true friends.

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• InnoDB Compression Improvements in MySQL 5.6

  - by Inaam Rana

  MySQL 5.6 comes with significant improvements for the compression support inside InnoDB. The enhancements that we'll talk about in this piece are also a good example of community contributions. The work on these was conceived, implemented and contributed by the engineers at Facebook. Before we plunge into the details let us familiarize ourselves with some of the key concepts surrounding InnoDB compression. In InnoDB compressed pages are fixed size. Supported sizes are 1, 2, 4, 8 and 16K. The compressed page size is specified at table creation time. InnoDB uses zlib for compression. InnoDB buffer pool will attempt to cache compressed pages like normal pages. However, whenever a page is actively used by a transaction, we'll always have the uncompressed version of the page as well i.e.: we can have a page in the buffer pool in compressed only form or in a state where we have both the compressed page and uncompressed version but we'll never have a page in uncompressed only form. On-disk we'll always only have the compressed page. When both compressed and uncompressed images are present in the buffer pool they are always kept in sync i.e.: changes are applied to both atomically. Recompression happens when changes are made to the compressed data. In order to minimize recompressions InnoDB maintains a modification log within a compressed page. This is the extra space available in the page after compression and it is used to log modifications to the compressed data thus avoiding recompressions. DELETE (and ROLLBACK of DELETE) and purge can be performed without recompressing the page. This is because the delete-mark bit and the system fields DB_TRX_ID and DB_ROLL_PTR are stored in uncompressed format on the compressed page. A record can be purged by shuffling entries in the compressed page directory. This can also be useful for updates of indexed columns, because UPDATE of a key is mapped to INSERT+DELETE+purge. A compression failure happens when we attempt to recompress a page and it does not fit in the fixed size. In such case, we first try to reorganize the page and attempt to recompress and if that fails as well then we split the page into two and recompress both pages. Now lets talk about the three major improvements that we made in MySQL 5.6.Logging of Compressed Page Images:InnoDB used to log entire compressed data on the page to the redo logs when recompression happens. This was an extra safety measure to guard against the rare case where an attempt is made to do recovery using a different zlib version from the one that was used before the crash. Because recovery is a page level operation in InnoDB we have to be sure that all recompress attempts must succeed without causing a btree page split. However, writing entire compressed data images to the redo log files not only makes the operation heavy duty but can also adversely affect flushing activity. This happens because redo space is used in a circular fashion and when we generate much more than normal redo we fill up the space much more quickly and in order to reuse the redo space we have to flush the corresponding dirty pages from the buffer pool.Starting with MySQL 5.6 a new global configuration parameter innodb_log_compressed_pages. The default value is true which is same as the current behavior. If you are sure that you are not going to attempt to recover from a crash using a different version of zlib then you should set this parameter to false. This is a dynamic parameter.Compression Level:You can now set the compression level that zlib should choose to compress the data. The global parameter is innodb_compression_level - the default value is 6 (the zlib default) and allowed values are 1 to 9. Again the parameter is dynamic i.e.: you can change it on the fly.Dynamic Padding to Reduce Compression Failures:Compression failures are expensive in terms of CPU. We go through the hoops of recompress, failure, reorganize, recompress, failure and finally page split. At the same time, how often we encounter compression failure depends largely on the compressibility of the data. In MySQL 5.6, courtesy of Facebook engineers, we have an adaptive algorithm based on per-index statistics that we gather about compression operations. The idea is that if a certain index/table is experiencing too many compression failures then we should try to pack the 16K uncompressed version of the page less densely i.e.: we let some space in the 16K page go unused in an attempt that the recompression won't end up in a failure. In other words, we dynamically keep adding 'pad' to the 16K page till we get compression failures within an agreeable range. It works the other way as well, that is we'll keep removing the pad if failure rate is fairly low. To tune the padding effort two configuration variables are exposed. innodb_compression_failure_threshold_pct: default 5, range 0 - 100,dynamic, implies the percentage of compress ops to fail before we start using to padding. Value 0 has a special meaning of disabling the padding. innodb_compression_pad_pct_max: default 50, range 0 - 75, dynamic, the  maximum percentage of uncompressed data page that can be reserved as pad.

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• Content Query Web Part and the Yes/No Field

  - by Bil Simser

  The Content Query Web Part (CQWP) is a pretty powerful beast. It allows you to do multiple site queries and aggregate the results. This is great for rolling up content and doing some summary type reporting. Here’s a trick to remember about Yes/No fields and using the CQWP. If you’re building a news style site and want to aggregate say all the announcements that people tag a certain way, up onto the home page this might be a solution. First we need to allow a way for users of all our sites to mark an announcement for inclusion on our Intranet Home Page. We’ll do this by just modifying the Announcement Content type and adding a Yes/No field to it. There are alternate ways of doing this like building a new Announcement type or stapling a feature to all sites to add our column but this is pretty low impact and only affects our current site collection so let’s go with it for now, okay? You can berate me in the comments about the proper way I should have done this part. Go to the Site Settings for the Site Collection and click on Site Content Types under the Galleries. This takes you to the gallery for this site and all subsites. Scroll down until you see the List Content Types and click on Announcements. Now we’re modifying the Announcement content type which affects all those announcement lists that are created by default if you’re building sites using the Team Site template (or creating a new Announcements list on any site for that matter). Click on Add from new site column under the Column list. This will allow us to create a new Yes/No field that users will see in Announcement items. This field will allow the user to flag the announcement for inclusion on the home page. Feel free to modify the fields as you see fit for your environment, this is just an example. Now that we’ve added the column to our Announcements Content type we can go into any site that has an announcement list, modify that announcement and flag it to be included on our home page. See the new Featured column? That was the result of modifying our Announcements Content Type on this site collection. Now we can move onto the dirty part, displaying it in a CQWP on the home page. And here is where the fun begins (and the head scratching should end). On our home page we want to drop a Content Query Web Part and aggregate any Announcement that’s been flagged as Featured by the users (we could also add the filter to handle Expires so we don’t show old content so go ahead and do that if you want). First add a CQWP to the page then modify the settings for the web part. In the first section, Query, we want the List Type to be set to Announcements and the Content type to be Announcement so set your options like this: Click Apply and you’ll see the results display all Announcements from any site in the site collection. I have five team sites created each with a unique announcement added to them. Now comes the filtering. We don’t want to include every announcement, only ones users flag using that Featured column we added. At first blush you might scroll down to the Additional Filters part of the Query options and set the Featured column to be equal to Yes: This seems correct doesn’t it? After all, the column is a Yes/No column and looking at an announcement in the site, it displays the field as Yes or No: However after applying the filter you get this result: (I have the announcements from Team Site 1 and Team Site 4 flagged as Featured) Huh? It’s BACKWARDS! Let’s confirm that. Go back in and change the Additional Filters section from Yes to No and hit Apply and you get this: Wait a minute? Shouldn’t I see Team Site 1 and 4 if the logic is backwards? Why am I seeing the same thing as before. What gives… For whatever reason, unknown to me, a Yes/No field (even though it displays as such) really uses 1 and 0 behind the scenes. Yeah, someone was stuck on using integer values for booleans when they wrote SharePoint (probably after a long night of white boarding ways to mess with developers heads) and came up with this. The solution is pretty simple but not very discoverable. Set the filter to include your flagged items like so: And it will filter the items marked as Featured correctly giving you this result: This kind of solution could also be extended and enhanced. Here are a few suggestions and ideas: Modify the ItemStyle.xsl file to add a new style for this aggregation which would include the first few paragraphs of the body (or perhaps add another field to the Content type called Excerpt or Summary and display that instead) Add an Image column to the Announcement Content type to include a Picture field and display it in the summary Add a Category choice field (Employee News, Current Events, Headlines, etc.) and add multiple CQWPs to the home page filtering each one on a different category I know some may find this topic old and dusty but I didn’t see a lot out there specifically on filtering the Yes/No fields and the whole 1/0 trick was a little wonky, so I figured a few pictures would help walk through overcoming yet another SharePoint weirdness. With a little work and some creative juices you can easily us the power of aggregation and the CQWP to build a news site from content on your team sites.

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• The sign of a true manager is delegation (C# style)

  - by MarkPearl

  Today I thought I would write a bit about delegates in C#. Up till recently I have managed to side step any real understanding of what delegates do and why they are useful – I mean, I know roughly what they do and have used them a lot, but I have never really got down dirty with them and mucked about. Recently however with my renewed interest in Silverlight delegates came up again as a possible solution to a particular problem, and suddenly I found myself opening a bland little console application to just see exactly how far I could take delegates with my limited knowledge. So, let’s first look at the MSDN definition of delegates… A delegate declaration defines a reference type that can be used to encapsulate a method with a specific signature. A delegate instance encapsulates a static or an instance method. Delegates are roughly similar to function pointers in C++; however, delegates are type-safe and secure. Well, don’t you love MSDN for such a useful definition. I must give it credit though… later on it really explains it a bit better by saying “A delegate lets you pass a function as a parameter. The type safety of delegates requires the function you pass as a delegate to have the same signature as the delegate declaration.” A little more reading up on delegates mentions that delegates are similar to interfaces in that they enable the separation of specification and implementation. A delegate declares a single method, while an interface declares a group of methods. So enough reading - lets look at some code and see a basic example of a delegate… Let’s assume we have a console application with a simple delegate declared called AdjustValue like below… class Program { private delegate int AdjustValue(int val); static void Main(string[] args) { } } In a sense, all we have said is that we will be creating one or more methods that follow the same pattern as AdjustValue – i.e. they will take one input value of type int and return an integer. We could then expand our code to have various methods that match the structure of our delegate AdjustValue (remember the structure is int xxx (int xxx)) class Program { private delegate int AdjustValue(int val); private static int Dbl(int val) { return val * 2; } private static int AlwaysOne(int val) { return 1; } static void Main(string[] args) { } }  Above I have expanded my project to have two methods, one called Dbl and the other AlwaysOne. Dbl always returns double the input val and AlwaysOne always returns 1. I could now declare a variable and assign it to be one of those functions, like the following… class Program { private delegate int AdjustValue(int val); private static int Dbl(int val) { return val * 2; } private static int AlwaysOne(int val) { return 1; } static void Main(string[] args) { AdjustValue myDelegate; myDelegate = Dbl; Console.WriteLine(myDelegate(1).ToString()); Console.ReadLine(); } } In this instance I have declared an instance of the AdjustValue delegate called myDelegate; I have then told myDelegate to point to the method Dbl, and then called myDelegate(1). What would the result be? Yes, in this instance it would be exactly the same as me calling the following code… static void Main(string[] args) { Console.WriteLine(Dbl(1).ToString()); Console.ReadLine(); }   So why all the extra work for delegates when we could just do what we did above and call the method directly? Well… that separation of specification to implementation comes to mind. So, this all seems pretty simple. Let’s take a slightly more complicated variation to the console application. Assume that my project is the same as the one previously except that my main method is adjusted as follows… static void Main(string[] args) { AdjustValue myDelegate; myDelegate = Dbl; myDelegate = AlwaysOne; Console.WriteLine(myDelegate(1).ToString()); Console.ReadLine(); } What would happen in this scenario? Quite simply “1” would be written to the console, the reason being that myDelegate was last pointing to the AlwaysOne method before it was called. Make sense? In a way, the myDelegate is a variable method that can be swapped and changed when needed. Let’s make the code a little more confusing by using a delegate in the declaration of another delegate as shown below… class Program { private delegate int AdjustValue(InputValue val); private delegate int InputValue(); private static int Dbl(InputValue val) { return val()*2; } private static int GetInputVal() { Console.WriteLine("Enter a whole number : "); return Convert.ToInt32(Console.ReadLine()); } static void Main(string[] args) { AdjustValue myDelegate; myDelegate = Dbl; Console.WriteLine(myDelegate(GetInputVal).ToString()); Console.ReadLine(); } }   Now it gets really interesting because it looks like we have passed a method into a function in the main method by declaring… Console.WriteLine(myDelegate(GetInputVal).ToString()); So, what it the output? Well, try take a guess on what will happen – then copy the code and see if you got it right. Well that brings me to the end of this short explanation of Delegates. Hopefully it made sense!

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• Using XA Transactions in Coherence-based Applications

  - by jpurdy

  While the costs of XA transactions are well known (e.g. increased data contention, higher latency, significant disk I/O for logging, availability challenges, etc.), in many cases they are the most attractive option for coordinating logical transactions across multiple resources. There are a few common approaches when integrating Coherence into applications via the use of an application server's transaction manager: Use of Coherence as a read-only cache, applying transactions to the underlying database (or any system of record) instead of the cache. Use of TransactionMap interface via the included resource adapter. Use of the new ACID transaction framework, introduced in Coherence 3.6.   Each of these may have significant drawbacks for certain workloads. Using Coherence as a read-only cache is the simplest option. In this approach, the application is responsible for managing both the database and the cache (either within the business logic or via application server hooks). This approach also tends to provide limited benefit for many workloads, particularly those workloads that either have queries (given the complexity of maintaining a fully cached data set in Coherence) or are not read-heavy (where the cost of managing the cache may outweigh the benefits of reading from it). All updates are made synchronously to the database, leaving it as both a source of latency as well as a potential bottleneck. This approach also prevents addressing "hot data" problems (when certain objects are updated by many concurrent transactions) since most database servers offer no facilities for explicitly controlling concurrent updates. Finally, this option tends to be a better fit for key-based access (rather than filter-based access such as queries) since this makes it easier to aggressively invalidate cache entries without worrying about when they will be reloaded. The advantage of this approach is that it allows strong data consistency as long as optimistic concurrency control is used to ensure that database updates are applied correctly regardless of whether the cache contains stale (or even dirty) data. Another benefit of this approach is that it avoids the limitations of Coherence's write-through caching implementation. TransactionMap is generally used when Coherence acts as system of record. TransactionMap is not generally compatible with write-through caching, so it will usually be either used to manage a standalone cache or when the cache is backed by a database via write-behind caching. TransactionMap has some restrictions that may limit its utility, the most significant being: The lock-based concurrency model is relatively inefficient and may introduce significant latency and contention. As an example, in a typical configuration, a transaction that updates 20 cache entries will require roughly 40ms just for lock management (assuming all locks are granted immediately, and excluding validation and writing which will require a similar amount of time). This may be partially mitigated by denormalizing (e.g. combining a parent object and its set of child objects into a single cache entry), at the cost of increasing false contention (e.g. transactions will conflict even when updating different child objects). If the client (application server JVM) fails during the commit phase, locks will be released immediately, and the transaction may be partially committed. In practice, this is usually not as bad as it may sound since the commit phase is usually very short (all locks having been previously acquired). Note that this vulnerability does not exist when a single NamedCache is used and all updates are confined to a single partition (generally implying the use of partition affinity). The unconventional TransactionMap API is cumbersome but manageable. Only a few methods are transactional, primarily get(), put() and remove(). The ACID transactions framework (accessed via the Connection class) provides atomicity guarantees by implementing the NamedCache interface, maintaining its own cache data and transaction logs inside a set of private partitioned caches. This feature may be used as either a local transactional resource or as logging XA resource. However, a lack of database integration precludes the use of this functionality for most applications. A side effect of this is that this feature has not seen significant adoption, meaning that any use of this is subject to the usual headaches associated with being an early adopter (greater chance of bugs and greater risk of hitting an unoptimized code path). As a result, for the moment, we generally recommend against using this feature. In summary, it is possible to use Coherence in XA-oriented applications, and several customers are doing this successfully, but it is not a core usage model for the product, so care should be taken before committing to this path. For most applications, the most robust solution is normally to use Coherence as a read-only cache of the underlying data resources, even if this prevents taking advantage of certain product features.

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• Silverlight animation not smooth

  - by Andrej

  Hi, When trying to animate objects time/frame based in Silverlight (in contrast to using something like DoubleAnimation or Storyboard, which is not suitable e.g. for fast paced games), for example moving a spaceship in a particular direction every frame, the movement is jumpy and not really smooth. The screen even seems to tear. There seems to be no difference between CompositionTarget and DistpatcherTimer. I use the following approach (in pseudocode): Register Handler to Tick-Event of a DispatcherTimer In each Tick: Compute the elapsed time from the last frame in milliseconds Object.X += movementSpeed * ellapsedMilliseconds This should result in a smooth movement, right? But it doesn't. Here is an example (Controls: WASD and Mouse): Silverlight Game. Although the effect I described is not too prevalent in this sample, I can assure you that even moving a single rectangle over a canvas produces a jumpy animation. Does someone have an idea how to minimize this. Are there other approaches to to frame based animation exept using Storyboards/DoubleAnimations which could solve this? Edit: Here a quick and dirty approach, animating a rectangle with minimum code (Controls: A and D) Animation Sample Xaml: <Grid x:Name="LayoutRoot" Background="Black"> <Canvas Width="1000" Height="400" Background="Blue"> <Rectangle x:Name="rect" Width="48" Height="48" Fill="White" Canvas.Top="200" Canvas.Left="0"/> </Canvas> </Grid> C#: private bool isLeft = false; private bool isRight = false; private DispatcherTimer timer = new DispatcherTimer(); private double lastUpdate; public Page() { InitializeComponent(); timer.Interval = TimeSpan.FromMilliseconds(1); timer.Tick += OnTick; lastUpdate = Environment.TickCount; timer.Start(); } private void OnTick(object sender, EventArgs e) { double diff = Environment.TickCount - lastUpdate; double x = Canvas.GetLeft(rect); if (isRight) x += 1 * diff; else if (isLeft) x -= 1 * diff; Canvas.SetLeft(rect, x); lastUpdate = Environment.TickCount; } private void UserControl_KeyDown(object sender, KeyEventArgs e) { if (e.Key == Key.D) isRight = true; if (e.Key == Key.A) isLeft = true; } private void UserControl_KeyUp(object sender, KeyEventArgs e) { if (e.Key == Key.D) isRight = false; if (e.Key == Key.A) isLeft = false; } Thanks! Andrej

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• Error when logging in with Machinist in Shoulda test

  - by user303747

  I am having some trouble getting the right usage of Machinist and Shoulda in my testing. Here is my test: context "on POST method rating" do p = Product.make u = nil setup do u = login_as post :vote, :rating => 3, :id => p end should "set rating for product to 3" do assert_equal p.get_user_vote(u), 3 end And here's my blueprints: Sham.login { Faker::Internet.user_name } Sham.name { Faker::Lorem.words} Sham.email { Faker::Internet.email} Sham.body { Faker::Lorem.paragraphs(2)} User.blueprint do login password "testpass" password_confirmation { password } email end Product.blueprint do name {Sham.name} user {User.make} end And my authentication test helper: def login_as(u = nil) u ||= User.make() @controller.stubs(:current_user).returns(u) u end The error I get is: /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/validations.rb:1090:in `save_without_dirty!': Validation failed: Login has already been taken, Email has already been taken (ActiveRecord::RecordInvalid) from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/dirty.rb:87:in `save_without_transactions!' from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/transactions.rb:200:in `save!' from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction' from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/transactions.rb:182:in `transaction' from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/transactions.rb:200:in `save!' from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/transactions.rb:208:in `rollback_active_record_state!' from /home/jason/moderndarwin/vendor/rails/activerecord/lib/active_record/transactions.rb:200:in `save!' from /usr/lib/ruby/gems/1.8/gems/machinist-1.0.6/lib/machinist/active_record.rb:55:in `make' from /home/jason/moderndarwin/test/blueprints.rb:37 from /usr/lib/ruby/gems/1.8/gems/machinist-1.0.6/lib/machinist.rb:77:in `generate_attribute_value' from /usr/lib/ruby/gems/1.8/gems/machinist-1.0.6/lib/machinist.rb:46:in `method_missing' from /home/jason/moderndarwin/test/blueprints.rb:37 from /usr/lib/ruby/gems/1.8/gems/machinist-1.0.6/lib/machinist.rb:20:in `instance_eval' from /usr/lib/ruby/gems/1.8/gems/machinist-1.0.6/lib/machinist.rb:20:in `run' from /usr/lib/ruby/gems/1.8/gems/machinist-1.0.6/lib/machinist/active_record.rb:53:in `make' from ./test/functional/products_controller_test.rb:25:in `__bind_1269805681_945912' from /home/jason/moderndarwin/vendor/gems/thoughtbot-shoulda-2.10.2/lib/shoulda/context.rb:293:in `call' from /home/jason/moderndarwin/vendor/gems/thoughtbot-shoulda-2.10.2/lib/shoulda/context.rb:293:in `merge_block' from /home/jason/moderndarwin/vendor/gems/thoughtbot-shoulda-2.10.2/lib/shoulda/context.rb:288:in `initialize' from /home/jason/moderndarwin/vendor/gems/thoughtbot-shoulda-2.10.2/lib/shoulda/context.rb:169:in `new' from /home/jason/moderndarwin/vendor/gems/thoughtbot-shoulda-2.10.2/lib/shoulda/context.rb:169:in `context' from ./test/functional/products_controller_test.rb:24 I can't figure out what it is I'm doing wrong... I have tested the login_as with my auth (Authlogic) in my user_controller testing. Any pointers in the right direction would be much appreciated!

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• Properly clean up excel interop objects revisited: Wrapper objects

  - by chiccodoro

  Hi all, Excel 2007 Hangs When Closing via .NET How to properly clean up Excel interop objects in C# How to properly clean up interop objects in C# All of these struggle with the problem that C# does not release the Excel COM objects properly after using them. There are mainly two directions of working around this issue: Kill the Excel process when Excel is not used anymore. Take care to assign each COM object used explicitly to a variable and to Marshal.ReleaseComObject all of these. Some have stated that 2 is too tedious and there is always some uncertainty whether you forget to stick to this rule at some places in the code. Still 1 seems dirty and dangerous to me, also I could imagine that in an environment with restricted access killing processes is not allowed. So I've been thinking about solving 2 by creating another proxy object model which mimics the Excel object model (for me, it would suffice to implement the objects I actually need). The principle would look as follows: Each Excel Interop class has its proxy which wraps an object of that class. The proxy releases the COM object in its destructor. The proxy mimics the interface of the Interop class (maybe by inheriting it). Any methods that usually return another COM object return a proxy instead. The other methods simply delegate the implementation to the inner COM object. This is a rough sketch of the code: public class Application : Microsoft.Office.Interop.Excel.Application { private Microsoft.Office.Interop.Excel.Application innerApplication = new Microsoft.Office.Interop.Excel.Application innerApplication(); ~Application() { Marshal.ReleaseCOMObject(innerApplication); } public Workbooks Workbooks { get { return new Workbooks(innerApplication.Workbooks); } } } public class Workbooks { private Microsoft.Office.Interop.Excel.Workbooks innerWorkbooks; Workbooks(Microsoft.Office.Interop.Excel.Workbooks innerWorkbooks) { this.innerWorkbooks = innerWorkbooks; } ~Workbooks() { Marshal.ReleaseCOMObject(innerWorkbooks); } } My questions to you are in particular: Who finds this a bad idea and why? Who finds this a gread idea? If so, why hasn't anybody implemented/published such a model yet? Just due to the effort, or am I missing a killing problem with that idea? Is it impossible/bad/dangerous to do the ReleaseCOMObject in the destructor? (I've only seen proposals to put it in a Dispose() rather than in a destructor - why?) If the approach makes sense, any suggestions to improve it?

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• Detecting which UIButton was pressed in a UITableView

  - by rein

  Hi, I have a UITableView with 5 UITableViewCells. Each cell contains a UIButton which is set up as follows: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSString *identifier = @"identifier"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier]; if (cell == nil) { cell = [[UITableView alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier]; [cell autorelelase]; UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(10, 5, 40, 20)]; [button addTarget:self action:@selector(buttonPressedAction:) forControlEvents:UIControlEventTouchUpInside]; [button setTag:1]; [cell.contentView addSubview:button]; [button release]; } UIButton *button = (UIButton *)[cell viewWithTag:1]; [button setTitle:@"Edit" forState:UIControlStateNormal]; return cell; } My question is this: in the buttonPressedAction: method, how do I know which button has been pressed. I've considered using tags but I'm not sure this is the best route. I'd like to be able to somehow tag the indexPath onto the control. - (void)buttonPressedAction:(id)sender { UIButton *button = (UIButton *)sender; // how do I know which button sent this message? // processing button press for this row requires an indexPath. } What's the standard way of doing this? Edit: I've kinda solved it by doing the following. I would still like to have an opinion whether this is the standard way of doing it or is there a better way? - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSString *identifier = @"identifier"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier]; if (cell == nil) { cell = [[UITableView alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier]; [cell autorelelase]; UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(10, 5, 40, 20)]; [button addTarget:self action:@selector(buttonPressedAction:) forControlEvents:UIControlEventTouchUpInside]; [cell.contentView addSubview:button]; [button release]; } UIButton *button = (UIButton *)[cell.contentView.subViews objectAtIndex:0]; [button setTag:indexPath.row]; [button setTitle:@"Edit" forState:UIControlStateNormal]; return cell; } - (void)buttonPressedAction:(id)sender { UIButton *button = (UIButton *)sender; int row = button.tag; } What's important to note is that I can't set the tag in the creation of the cell since the cell might be dequeued instead. It feels very dirty. There must be a better way.

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• Unity framework DependencyAttribute only works for public properties?

  - by rally25rs

  I was trying to clean up some accessability stuff in my code, and inadvertently broke Unity dependency injection. After a while I realized that I marked some public properties that I didn't really want exposed outside my DLLs to internal. Then I started getting exceptions. So it seems that using the [Dependency] attribute in Unity only works for public properties. I suppose that makes sense since the internal and private props wouldnt be visible to the Unity assembly, but feels really dirty to have a bunch of public properties that you never want anyone to set or be able to set, other than Unity. Is there a way to let unity set internal or private properties too? Here is the unit test I'd like to see pass. Currently only the public prop test passes: [TestFixture] public class UnityFixture { [Test] public void UnityCanSetPublicDependency() { UnityContainer container = new UnityContainer(); container.RegisterType<HasPublicDep, HasPublicDep>(); container.RegisterType<TheDep, TheDep>(); var i = container.Resolve<HasPublicDep>(); Assert.IsNotNull(i); Assert.IsNotNull(i.dep); } [Test] public void UnityCanSetInternalDependency() { UnityContainer container = new UnityContainer(); container.RegisterType<HasInternalDep, HasInternalDep>(); container.RegisterType<TheDep, TheDep>(); var i = container.Resolve<HasInternalDep>(); Assert.IsNotNull(i); Assert.IsNotNull(i.dep); } [Test] public void UnityCanSetPrivateDependency() { UnityContainer container = new UnityContainer(); container.RegisterType<HasPrivateDep, HasPrivateDep>(); container.RegisterType<TheDep, TheDep>(); var i = container.Resolve<HasPrivateDep>(); Assert.IsNotNull(i); Assert.IsNotNull(i.depExposed); } } public class HasPublicDep { [Dependency] public TheDep dep { get; set; } } public class HasInternalDep { [Dependency] internal TheDep dep { get; set; } } public class HasPrivateDep { [Dependency] private TheDep dep { get; set; } public TheDep depExposed { get { return this.dep; } } } public class TheDep { } Updated: I noticed the call stack to set the property passed from: UnityCanSetPublicDependency() --> Microsoft.Practices.Unity.dll --> Microsoft.Practices.ObjectBuilder2.dll --> HasPublicDep.TheDep.set() So in an attempt to at least make the internal version work, I added these to my assembly's properties: [assembly: InternalsVisibleTo("Microsoft.Practices.Unity")] [assembly: InternalsVisibleTo("Microsoft.Practices.Unity.Configuration")] [assembly: InternalsVisibleTo("Microsoft.Practices.ObjectBuilder2")] However, no change. Unity/ObjectBuilder still won't set the internal property

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• Semi-complex aggregate select statement confusion

  - by Ian Henry

  Alright, this problem is a little complicated, so bear with me. I have a table full of data. One of the table columns is an EntryDate. There can be multiple entries per day. However, I want to select all rows that are the latest entry on their respective days, and I want to select all the columns of said table. One of the columns is a unique identifier column, but it is not the primary key (I have no idea why it's there; this is a pretty old system). For purposes of demonstration, say the table looks like this: create table ExampleTable ( ID int identity(1,1) not null, PersonID int not null, StoreID int not null, Data1 int not null, Data2 int not null, EntryDate datetime not null ) The primary key is on PersonID and StoreID, which logically defines uniqueness. Now, like I said, I want to select all the rows that are the latest entries on that particular day (for each Person-Store combination). This is pretty easy: --Figure 1 select PersonID, StoreID, max(EntryDate) from ExampleTable group by PersonID, StoreID, dbo.dayof(EntryDate) Where dbo.dayof() is a simple function that strips the time component from a datetime. However, doing this loses the rest of the columns! I can't simply include the other columns, because then I'd have to group by them, which would produce the wrong results (especially since ID is unique). I have found a dirty hack that will do what I want, but there must be a better way -- here's my current solution: select cast(null as int) as ID, PersonID, StoreID, cast(null as int) as Data1, cast(null as int) as Data2, max(EntryDate) as EntryDate into #StagingTable from ExampleTable group by PersonID, StoreID, dbo.dayof(EntryDate) update Target set ID = Source.ID, Data1 = Source.Data1, Data2 = Source.Data2, from #StagingTable as Target inner join ExampleTable as Source on Source.PersonID = Target.PersonID and Source.StoreID = Target.StoreID and Source.EntryDate = Target.EntryDate This gets me the correct data in #StagingTable but, well, look at it! Creating a table with null values, then doing an update to get the values back -- surely there's a better way to do this? A single statement that will get me all the values the first time? It is my belief that the correct join on that original select (Figure 1) would do the trick, like a self-join or something... but how do you do that with the group by clause? I cannot find the right syntax to make the query execute. I am pretty new with SQL, so it's likely that I'm missing something obvious. Any suggestions? (Working in T-SQL, if it makes any difference)

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• .NET RegEx "Memory Leak" investigation

  - by Kevin Pullin

  I recently looked into some .NET "memory leaks" (i.e. unexpected, lingering GC rooted objects) in a WinForms app. After loading and then closing a huge report, the memory usage did not drop as expected even after a couple of gen2 collections. Assuming that the reporting control was being kept alive by a stray event handler I cracked open WinDbg to see what was happening... Using WinDbg, the !dumpheap -stat command reported a large amount of memory was consumed by string instances. Further refining this down with the !dumpheap -type System.String command I found the culprit, a 90MB string used for the report, at address 03be7930. The last step was to invoke !gcroot 03be7930 to see which object(s) were keeping it alive. My expectations were incorrect - it was not an unhooked event handler hanging onto the reporting control (and report string), but instead it was held on by a System.Text.RegularExpressions.RegexInterpreter instance, which itself is a descendant of a System.Text.RegularExpressions.CachedCodeEntry. Now, the caching of Regexs is (somewhat) common knowledge as this helps to reduce the overhead of having to recompile the Regex each time it is used. But what then does this have to do with keeping my string alive? Based on analysis using Reflector, it turns out that the input string is stored in the RegexInterpreter whenever a Regex method is called. The RegexInterpreter holds onto this string reference until a new string is fed into it by a subsequent Regex method invocation. I'd expect similar behaviour by hanging onto Regex.Match instances and perhaps others. The chain is something like this: Regex.Split, Regex.Match, Regex.Replace, etc Regex.Run RegexScanner.Scan (RegexScanner is the base class, RegexInterpreter is the subclass described above). The offending Regex is only used for reporting, rarely used, and therefore unlikely to be used again to clear out the existing report string. And even if the Regex was used at a later point, it would probably be processing another large report. This is a relatively significant problem and just plain feels dirty. All that said, I found a few options on how to resolve, or at least work around, this scenario. I'll let the community respond first and if no takers come forward I will fill in any gaps in a day or two.

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• Does my fat-client application belong in the MVC pattern?

  - by boatingcow

  The web-based application I’m currently working on is growing arms and legs! It’s basically an administration system which helps users to keep track of bookings, user accounts, invoicing etc. It can also be accessed via a couple of different websites using a fairly crude API. The fat-client design loosely follows the MVC pattern (or perhaps MVP) with a php/MySQL backend, Front Controller, several dissimilar Page Controllers, a liberal smattering of object-oriented and procedural Models, a confusing bunch of Views and templates, some JavaScripts, CSS files and Flash objects. The programmer in me is a big fan of the principle of “Separation of Concerns” and on that note, I’m currently trying to figure out the best way to separate and combine the various concerns as the project grows and more people contribute to it. The problem we’re facing is that although JavaScript (or Flash with ActionScript) is normally written with the template, hence part of the View and decoupled from the Controller and Model, we find that it actually encompasses the entire MVC pattern... Swap an image with an onmouseover event - that’s Behaviour. Render a datagrid - we’re manipulating the View. Send the result of reordering a list via AJAX - now we’re in Control. Check a form field to see if an email address is in a valid format - we’re consulting the Model. Is it wise to let the database people write up the validation Model with jQuery? Can the php programmers write the necessary Control structures in JavaScript? Can the web designers really write a functional AJAX form for their View? Should there be a JavaScript overlord for every project? If the MVC pattern could be applied to the people instead of the code, we would end up with this: Model - the database boffins - “SELECT * FROM mind WHERE interested IS NULL” Control - pesky programmers - “class Something extends NothingAbstractClass{…}” View - traditionally the domain of the graphic/web designer - “” …and a new layer: Behaviour - interaction and feedback designer - “CSS3 is the new black…” So, we’re refactoring and I’d like to stick to best practice design, but I’m not sure how to proceed. I don’t want to reinvent the wheel, so would anyone have any hints or tips as to what pattern I should be looking at or any code samples from someone who’s already done the dirty work? As the programmer guy, how can I rewrite the app for backend and front end whilst keeping the two separate? And before you ask, yes I’ve looked at Zend, CodeIgnitor, Symfony, etc., and no, they don’t seem to cross the boundary between server logic and client logic!

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• SQL Server to PostgreSQL - Migration and design concerns

  - by youwhut

  Currently migrating from SQL Server to PostgreSQL and attempting to improve a couple of key areas on the way: I have an Articles table: CREATE TABLE [dbo].[Articles]( [server_ref] [int] NOT NULL, [article_ref] [int] NOT NULL, [article_title] [varchar](400) NOT NULL, [category_ref] [int] NOT NULL, [size] [bigint] NOT NULL ) Data (comma delimited text files) is dumped on the import server by ~500 (out of ~1000) servers on a daily basis. Importing: Indexes are disabled on the Articles table. For each dumped text file Data is BULK copied to a temporary table. Temporary table is updated. Old data for the server is dropped from the Articles table. Temporary table data is copied to Articles table. Temporary table dropped. Once this process is complete for all servers the indexes are built and the new database is copied to a web server. I am reasonably happy with this process but there is always room for improvement as I strive for a real-time (haha!) system. Is what I am doing correct? The Articles table contains ~500 million records and is expected to grow. Searching across this table is okay but could be better. i.e. SELECT * FROM Articles WHERE server_ref=33 AND article_title LIKE '%criteria%' has been satisfactory but I want to improve the speed of searching. Obviously the "LIKE" is my problem here. Suggestions? SELECT * FROM Articles WHERE article_title LIKE '%criteria%' is horrendous. Partitioning is a feature of SQL Server Enterprise but $$$ which is one of the many exciting prospects of PostgreSQL. What performance hit will be incurred for the import process (drop data, insert data) and building indexes? Will the database grow by a huge amount? The database currently stands at 200 GB and will grow. Copying this across the network is not ideal but it works. I am putting thought into changing the hardware structure of the system. The thought process of having an import server and a web server is so that the import server can do the dirty work (WITHOUT indexes) while the web server (WITH indexes) can present reports. Maybe reducing the system down to one server would work to skip the copying across the network stage. This one server would have two versions of the database: one with the indexes for delivering reports and the other without for importing new data. The databases would swap daily. Thoughts? This is a fantastic system, and believe it or not there is some method to my madness by giving it a big shake up. UPDATE: I am not looking for help with relational databases, but hoping to bounce ideas around with data warehouse experts.

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• JSON Post To Rails From Android

  - by Stealthnh

  I'm currently working on an android app that interfaces with a Ruby on Rails app through XML and JSON. I can currently pull all my posts from my website through XML but I can't seem to post via JSON. My app currently builds a JSON object from a form that looks a little something like this: { "post": { "other_param": "1", "post_content": "Blah blah blah" } } On my server I believe the Create method in my Posts Controller is set up correctly: def create @post = current_user.posts.build(params[:post]) respond_to do |format| if @post.save format.html { redirect_to @post, notice: 'Post was successfully created.' } format.json { render json: @post, status: :created, location: @post } format.xml { render xml: @post, status: :created, location: @post } else format.html { render action: "new" } format.json { render json: @post.errors, status: :unprocessable_entity } format.xml { render xml: @post.errors, status: :unprocessable_entity } end end end And in my android app I have a method that takes that JSON Object I posted earlier as a parameter along with the username and password for being authenticated (Authentication is working I've tested it, and yes Simple HTTP authentication is probably not the best choice but its a quick and dirty fix) and it then sends the JSON Object through HTTP POST to the rails server. This is that method: public static void sendPost(JSONObject post, String email, String password) { DefaultHttpClient client = new DefaultHttpClient(); client.getCredentialsProvider().setCredentials(new AuthScope(null,-1), new UsernamePasswordCredentials(email,password)); HttpPost httpPost = new HttpPost("http://mysite.com/posts"); JSONObject holder = new JSONObject(); try { holder.put("post", post); StringEntity se = new StringEntity(holder.toString()); Log.d("SendPostHTTP", holder.toString()); httpPost.setEntity(se); httpPost.setHeader("Content-Type","application/json"); } catch (UnsupportedEncodingException e) { Log.e("Error",""+e); e.printStackTrace(); } catch (JSONException js) { js.printStackTrace(); } HttpResponse response = null; try { response = client.execute(httpPost); } catch (ClientProtocolException e) { e.printStackTrace(); Log.e("ClientProtocol",""+e); } catch (IOException e) { e.printStackTrace(); Log.e("IO",""+e); } HttpEntity entity = response.getEntity(); if (entity != null) { try { entity.consumeContent(); } catch (IOException e) { Log.e("IO E",""+e); e.printStackTrace(); } } } Currently when I call this method and pass it the correct JSON Object it doesn't do anything and I have no clue why or how to figure out what is going wrong. Is my JSON still formatted wrong, does there really need to be that holder around the other data? Or do I need to use something other than HTTP POST? Or is this just something on the Rails end? A route or controller that isn't right? I'd be really grateful if someone could point me in the right direction, because I don't know where to go from here.

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• who free's setvbuf buffer?

  - by Evan Teran

  So I've been digging into how the stdio portion of libc is implemented and I've come across another question. Looking at man setvbuf I see the following: When the first I/O operation occurs on a file, malloc(3) is called, and a buffer is obtained. This makes sense, your program should have a malloc in it for I/O unless you actually use it. My gut reaction to this is that libc will clean up its own mess here. Which I can only assume it does because valgrind reports no memory leaks (they could of course do something dirty and not allocate it via malloc directly... but we'll assume that it literally uses malloc for now). But, you can specify your own buffer too... int main() { char *p = malloc(100); setvbuf(stdio, p, _IOFBF, 100); puts("hello world"); } Oh no, memory leak! valgrind confirms it. So it seems that whenever stdio allocates a buffer on its own, it will get deleted automatically (at the latest on program exit, but perhaps on stream close). But if you specify the buffer explicitly, then you must clean it up yourself. There is a catch though. The man page also says this: You must make sure that the space that buf points to still exists by the time stream is closed, which also happens at program termination. For example, the following is invalid: Now this is getting interesting for the standard streams. How would one properly clean up a manually allocated buffer for them, since they are closed in program termination? I could imagine a "clean this up when I close flag" inside the file struct, but it get hairy because if I read this right doing something like this: setvbuf(stdio, 0, _IOFBF, 100); printf("hello "); setvbuf(stdio, 0, _IOLBF, 100); printf("world\n"); would cause 2 allocations by the standard library because of this sentence: If the argument buf is NULL, only the mode is affected; a new buffer will be allocated on the next read or write operation.

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