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• Vim autocommand on BufDelete prevents opening help window

  - by Kyle Strand

  I have the autocommand described here in my .vimrc: http://superuser.com/a/669463/199803 EDIT: Copied into body of question for convenience: function CountListedBuffers() let cnt = 0 for nr in range(1,bufnr("$")) if buflisted(nr) && ! empty(bufname(nr)) let cnt += 1 endif endfor return cnt endfunction function QuitIfLastBuffer() if CountListedBuffers() == 1 :q endif endfunction autocmd BufDelete * :call QuitIfLastBuffer() Bizarrely, though, it seems that if I have exactly one listed buffer, and I try to use the :help command, the help window fails to open (or perhaps opens and is immediately closed). If I comment out that autocommand line in my .vimrc, this behavior no longer occurs. Why is this happening, and how can I fix it? Why would :h even trigger the BufDelete event? EDIT: setting verbosity to level 12, I can see that the BufDelete event is indeed occurring. Here's the portion of the output that looks relevant to me: Executing BufAdd Auto commands for "*" autocommand call <SID>BMAdd() calling function <SNR>6_BMAdd calling function <SNR>6_BMAdd..<SNR>6_BMFilename calling function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMMunge calling function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMMunge..<SNR>6_BMTruncName function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMMunge..<SNR>6_BMTruncName returning '/usr/local/share/vim/vim74/doc' continuing in function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMMunge function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMMunge returning 'help\.txt\ (4)\^I/usr/local/share/vim/vim74/doc' continuing in function <SNR>6_BMAdd..<SNR>6_BMFilename calling function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMHash function <SNR>6_BMAdd..<SNR>6_BMFilename..<SNR>6_BMHash returning #340582286 continuing in function <SNR>6_BMAdd..<SNR>6_BMFilename function <SNR>6_BMAdd..<SNR>6_BMFilename returning #0 continuing in function <SNR>6_BMAdd function <SNR>6_BMAdd returning #0 continuing in BufAdd Auto commands for "*" Executing BufDelete Auto commands for "*" autocommand :call QuitIfLastBuffer()

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• FTP Server upload and filesystem questions

  - by Alex

  I'm a photographer who mainly does event photography. A while ago I bought myself a Nikon WT-4 wireless transmitter, a small device which connects via USB to my Nikon D700 DSLR, and then establishes a WiFi connection to an existing WLAN. It can then upload any pictures I take via FTP to an FTP server somewhere in the network. On my laptop I then have a piece of software which will check a given folder on the disk regularly, this software is smart enough to look at the modified file timestamp, if this timestamp is less than 10 seconds ago, it will not attempt to import the folder and skip the file in this iteration of the import scan. The problem I've discovered seems to be inherent to the FTP protocol, as I have the same problem with Windows 7 built in IIS server, as I do with FileZilla FTP server. When the transmitter starts to upload a file, the FTP server will create a small 300-500 KB file with the correct filename on the disk, but then do nothing with the file until it has completely received the file via FTP. So it seems to create this small dummy file, and then buffer the remainder of the FTP upload until it's finished, and then dump the rest of the file into the dummy file making it the correct size. Problem is, these uploads take about 15-30 seconds depending on reception, but since the folder watch tool will already try to import any file older than 10 seconds, it will always try to import the small dummy files which obviously fails as they're not copmlete yet. Is there any way to 'disable' this behaviour? Ideally I would like my file only to show up once it's been completely uploaded. Or perhaps someone knows another FTP server application (it has to run on win7) which does not show this behaviour?

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• cause for mysql crash

  - by user1322092

  A cron job automatically restarted my mysql database. What's the cause for the crash, or can you suggest how to resolve or monitor. I would REALLY appreciate your input. 120715 14:38:58 mysqld started 120715 14:38:58 InnoDB: Started; log sequence number 0 411137570 120715 14:38:58 [Note] /usr/libexec/mysqld: ready for connections. Version: '5.0.95' socket: '/var/lib/mysql/mysql.sock' port: 3306 Source distribution 120715 15:14:21 [Note] /usr/libexec/mysqld: Normal shutdown 120715 15:14:23 InnoDB: Starting shutdown... 120715 15:14:25 InnoDB: Shutdown completed; log sequence number 0 411166467 120715 15:14:25 [Note] /usr/libexec/mysqld: Shutdown complete 120715 08:14:25 mysqld ended 120715 08:14:26 mysqld started 120715 8:14:26 InnoDB: Started; log sequence number 0 411166467 120715 8:14:26 [Note] /usr/libexec/mysqld: ready for connections. Version: '5.0.95' socket: '/var/lib/mysql/mysql.sock' port: 3306 Source distribution 121212 09:15:32 mysqld started InnoDB: The log sequence number in ibdata files does not match InnoDB: the log sequence number in the ib_logfiles! 121212 9:15:58 InnoDB: Database was not shut down normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files... InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer... 121212 9:17:28 InnoDB: Started; log sequence number 0 554145193 121212 9:17:57 [Note] /usr/libexec/mysqld: ready for connections. Version: '5.0.95' socket: '/var/lib/mysql/mysql.sock' port: 3306 Source distribution

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• Eee PC 1015BX ram compatibility?

  - by AdrianaMX

  Asus Eee PC 1015BX Operating System Windows 7 Starter, 32bit CPU AMD Fusion APU C60 1.0GHz (dual core) Processor Graphic AMD Radeon HD 6290 (256 MB Shared) Memory DDR3, 1 x SO-DIMM, 1GB I have upgraded the preloaded "Windows 7 Starter" to "Windows 7 Professional" I want to upgrade the ram, from 1gb (factory) to 4 gb. What should i buy? SODDR3, 4GB, 1066MHZ, PC3-8500, 204PIN? or SODDR3, 4GB, 1333MHZ, PC3-10666, 204PIN? I already know that Windows 7 32-bits can't handle 4gb, only 3gb (but 3gb is better than one stick of 2gb). ASUS send me this link, but i think they are wrong, (or Insufficient Information for me) http://www.kingston.com/us/memory/search/Default.aspx?DeviceType=3&Mfr=ASU&Line=Eee%20PC&Model=71404 Thank you. CPU-Z Chipset Memory Type DDR3 Memory Size 750 MBytes Memory Frequency 532.2 MHz (3:16) CAS# latency (CL) 7.0 RAS# to CAS# delay (tRCD) 7 RAS# Precharge (tRP) 7 Cycle Time (tRAS) 20 Bank Cycle Time (tRC) 27 Memory SPD NO INFO AIDA64 North bridge Properties North bridge AMD K14 IMC Supported Memory Types DDR3-800, DDR3-1066 SDRAM Memory Slots DRAM Slot #1 1 GB (DDR3 SDRAM) Integrated Graphics Controller Graphics Controller Type AMD Radeon HD 6290 (Wrestler) Graphics Controller Status Enabled Graphics Frame Buffer Size 256 MB

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• How can I get (g)Vim to display the character count of the current file?

  - by OwenP

  I like to write tutorials and articles for a programming forum I frequent. This forum has a character limit per post. I've used Notepad++ in the past to write posts and it keeps a live character count in the status bar. I'm starting to use gVim more and I really don't want to go back to Notepad++ at this point, but it is very useful to have this character count. If I go over the count, I usually end up pasting the post into Notepad++ so I can see when I've trimmed enough to get by the limit. I've seen suggestions that :set ruler would help, but this only gives the character count via the current column index on the current line. This would be great if I didn't use paragraph breaks, but I'm sure you'd agree that reading several thousand characters in one paragraph is not comfortable. I read the help and thought that rulerformat would work, but after looking over the statusline format it uses I didn't see anything that gives a character count for the current buffer. I've seen that there are plugins that add this, but I'm still dipping my toes into gVim and I'm not sure I want to load random plugins before I understand what they do. I'd prefer to use something built in to vim, but if it doesn't exist it doesn't exist. What should I do to accomplish my goal? If it involves a plugin, do you use it and how well does it work?

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• Customizing tmux status to represent current working directory and files

  - by user69397

  I've been playing with this for a couple of days, so I'm sure I'm missing something simple. Love tmux. Using it for development and have so many windows I need a better way of distinguishing them in the status bar and in the buffer list. Seeing a list of "bash" and "vim" isn't really helpful at all. And since they're all on the same host - don't care about the hostname right now. I'd like to show the current working directory, and the file being worked on. For example when I view the list of buffers I currently see: (0) 0: vim [100x44] (1 panes) "murph" (1) 1: vim [100x44] (1 panes) "murph" (2) 2: bash- [100x44] (1 panes) "murph" (3) 3: bash* [100x44] (1 panes) "murph" Here's what I'd like to see 0:vim main.py ~/devl/project1 1:vim index.html ~/devl/samples/staticfiles 2:bash ~/devl/sandbox 3:bash ~/.vimrc I'd like to see similar info in the status bar for each individual window. While I am able to get PWD to show up in the status bar of a window, it's only the working directory from where tmux was launched. This isn't any help as I change directories. I'm hoping this can be done without a bunch of scripts. Thanks all.

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• Debian boot problems

  - by psp

  I've got Debian server with one disk. No dual boot or anything fancy. Just Debian 6.0 (Squeeze). I rebooted the server today and now it doesn't boot. I get the following (from GRUB): error: hd0,msdos out of disk I then get a grub prompt grub rescue> I've been googling for ages with no luck. /etc/fstab > #/etc/fstab: static file system information. > # > # <file system> <mount point> <type> <options> <dump> <pass> > aufs / aufs rw 0 0 > tmpfs /tmp tmpfs nosuid,nodev 0 0 I've run debian rescue mode and looked through the syslog. I see hundreds of entries like this: Jun 30 22:51:08 kernel: [ 615.217382] sd 2:0:0:0: [sda] Unhandled error code Jun 30 22:51:08 kernel: [ 615.217385] sd 2:0:0:0: [sda] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK Jun 30 22:51:08 kernel: [ 615.217389] sd 2:0:0:0: [sda] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00 Jun 30 22:51:08 kernel: [ 615.217399] end_request: I/O error, dev sda, logical block 0 Jun 30 22:51:08 kernel: [ 615.217402] Buffer I/O error on device sda, logical block 0

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• C++ Multithreading with pthread is blocking (including sockets)

  - by Sebastian Büttner

  I am trying to implement a multi threaded application with pthread. I did implement a thread class which looks like the following and I call it later twice (or even more), but it seems to block instead of execute the threads parallel. Here is what I got until now: The Thread Class is an abstract class which has the abstract method "exec" which should contain the thread code in a derive class (I did a sample of this, named DerivedThread) Thread.hpp #ifndef THREAD_H_ #define THREAD_H_ #include <pthread.h> class Thread { public: Thread(); void start(); void join(); virtual int exec() = 0; int exit_code(); private: static void* thread_router(void* arg); void exec_thread(); pthread_t pth_; int code_; }; #endif /* THREAD_H_ */ And Thread.cpp #include <iostream> #include "Thread.hpp" /*****************************/ using namespace std; Thread::Thread(): code_(0) { cout << "[Thread] Init" << endl; } void Thread::start() { cout << "[Thread] Created Thread" << endl; pthread_create( &pth_, NULL, Thread::thread_router, reinterpret_cast<void*>(this)); } void Thread::join() { cout << "[Thread] Join Thread" << endl; pthread_join(pth_, NULL); } int Thread::exit_code() { return code_; } void Thread::exec_thread() { cout << "[Thread] Execute" << endl; code_ = exec(); } void* Thread::thread_router(void* arg) { cout << "[Thread] exec_thread function in thread" << endl; reinterpret_cast<Thread*>(arg)->exec_thread(); return NULL; } DerivedThread.hpp #include "Thread.hpp" class DerivedThread : public Thread { public: DerivedThread(); virtual ~DerivedThread(); int exec(); void Close() = 0; DerivedThread.cpp [...] #include "DerivedThread.cpp" [...] int DerivedThread::exec() { //code to be executed do { cout << "Thread executed" << endl; usleep(1000000); } while (true); //dummy, just to let it run for a while } [...] Basically, I am calling this like the here: DerivedThread *thread; cout << "Creating Thread" << endl; thread = new DerivedThread(); cout << "Created thread, starting..." << endl; thread->start(); cout << "Started thread" << endl; cout << "Creating 2nd Thread" << endl; thread = new DerivedThread(); cout << "Created 2nd thread, starting..." << endl; thread->start(); cout << "Started 2nd thread" << endl; What is working great if I am only starting one of these Threads , but if I start multiple which should run together (not synced, only parallel) . But I discovered, that the thread is created, then as it tries to execute it (via start) the problem seems to block until the thread has closed. After that the next Thread is processed. I thought that pthread would do it unblocked for me, so what did I wrong? A sample output might be: Creating Thread [Thread] Thread Init Created thread, starting... [Thread] Created thread [Thread] exec_thread function in thread [Thread] Execute Thread executed Thread executed Thread executed Thread executed Thread executed Thread executed Thread executed .... Until Thread 1 is not terminated, a Thread 2 won't be created not executed. The process above is executed in an other class. Just for the information: I am trying to create a multi threaded server. The concept is like this: MultiThreadedServer Class has a main loop, like this one: ::inet::ServerSock *sock; //just a simple self made wrapper class for sockets DerivedThread *thread; for (;;) { sock = new ::inet::ServerSock(); this->Socket->accept( *sock ); cout << "Creating Thread" << endl; //Threads (according to code sample above) thread = new DerivedThread(sock); //I did not mentoine the parameter before as it was not neccesary, in fact, I pass the socket handle with the connected socket to the thread cout << "Created thread, starting..." << endl; thread->start(); cout << "Started thread" << endl; } So I thought that this would loop over and over and wait for new connections to accept. and when a new client arrives, I am creating a new thread and give the thread the connected socket as a parameter. In the DerivedThread::exec I am doing the handling for the connected client. Like: [...] do { [...] if (this-sock_-read( Buffer, sizeof(PacketStruc) ) 0) { cout << "[Handler_Base] Recv Packet" << endl; //handle the packet } else { Connected = false; } delete Buffer; } while ( Connected ); So I loop in the created thread as long as the client keeps the connection. I think, that the socket may cause the blocking behaviour. Edit: I figured out, that it is not the read() loop in the DerivedThread Class as I simply replaced it with a loop over a simple cout-usleep part. It did also only execute the first one and after first thread finished, the 2nd one was executed. Many thanks and best regards, Sebastian

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• How do I get .NET to garbage collect aggressively?

  - by mmr

  I have an application that is used in image processing, and I find myself typically allocating arrays in the 4000x4000 ushort size, as well as the occasional float and the like. Currently, the .NET framework tends to crash in this app apparently randomly, almost always with an out of memory error. 32mb is not a huge declaration, but if .NET is fragmenting memory, then it's very possible that such large continuous allocations aren't behaving as expected. Is there a way to tell the garbage collector to be more aggressive, or to defrag memory (if that's the problem)? I realize that there's the GC.Collect and GC.WaitForPendingFinalizers calls, and I've sprinkled them pretty liberally through my code, but I'm still getting the errors. It may be because I'm calling dll routines that use native code a lot, but I'm not sure. I've gone over that C++ code, and make sure that any memory I declare I delete, but still I get these C# crashes, so I'm pretty sure it's not there. I wonder if the C++ calls could be interfering with the GC, making it leave behind memory because it once interacted with a native call-- is that possible? If so, can I turn that functionality off? EDIT: Here is some very specific code that will cause the crash. According to this SO question, I do not need to be disposing of the BitmapSource objects here. Here is the naive version, no GC.Collects in it. It generally crashes on iteration 4 to 10 of the undo procedure. This code replaces the constructor in a blank WPF project, since I'm using WPF. I do the wackiness with the bitmapsource because of the limitations I explained in my answer to @dthorpe below as well as the requirements listed in this SO question. public partial class Window1 : Window { public Window1() { InitializeComponent(); //Attempts to create an OOM crash //to do so, mimic minute croppings of an 'image' (ushort array), and then undoing the crops int theRows = 4000, currRows; int theColumns = 4000, currCols; int theMaxChange = 30; int i; List<ushort[]> theList = new List<ushort[]>();//the list of images in the undo/redo stack byte[] displayBuffer = null;//the buffer used as a bitmap source BitmapSource theSource = null; for (i = 0; i < theMaxChange; i++) { currRows = theRows - i; currCols = theColumns - i; theList.Add(new ushort[(theRows - i) * (theColumns - i)]); displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create(currCols, currRows, 96, 96, PixelFormats.Gray8, null, displayBuffer, (currCols * PixelFormats.Gray8.BitsPerPixel + 7) / 8); System.Console.WriteLine("Got to change " + i.ToString()); System.Threading.Thread.Sleep(100); } //should get here. If not, then theMaxChange is too large. //Now, go back up the undo stack. for (i = theMaxChange - 1; i >= 0; i--) { displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create((theColumns - i), (theRows - i), 96, 96, PixelFormats.Gray8, null, displayBuffer, ((theColumns - i) * PixelFormats.Gray8.BitsPerPixel + 7) / 8); System.Console.WriteLine("Got to undo change " + i.ToString()); System.Threading.Thread.Sleep(100); } } } Now, if I'm explicit in calling the garbage collector, I have to wrap the entire code in an outer loop to cause the OOM crash. For me, this tends to happen around x = 50 or so: public partial class Window1 : Window { public Window1() { InitializeComponent(); //Attempts to create an OOM crash //to do so, mimic minute croppings of an 'image' (ushort array), and then undoing the crops for (int x = 0; x < 1000; x++){ int theRows = 4000, currRows; int theColumns = 4000, currCols; int theMaxChange = 30; int i; List<ushort[]> theList = new List<ushort[]>();//the list of images in the undo/redo stack byte[] displayBuffer = null;//the buffer used as a bitmap source BitmapSource theSource = null; for (i = 0; i < theMaxChange; i++) { currRows = theRows - i; currCols = theColumns - i; theList.Add(new ushort[(theRows - i) * (theColumns - i)]); displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create(currCols, currRows, 96, 96, PixelFormats.Gray8, null, displayBuffer, (currCols * PixelFormats.Gray8.BitsPerPixel + 7) / 8); } //should get here. If not, then theMaxChange is too large. //Now, go back up the undo stack. for (i = theMaxChange - 1; i >= 0; i--) { displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create((theColumns - i), (theRows - i), 96, 96, PixelFormats.Gray8, null, displayBuffer, ((theColumns - i) * PixelFormats.Gray8.BitsPerPixel + 7) / 8); GC.WaitForPendingFinalizers();//force gc to collect, because we're in scenario 2, lots of large random changes GC.Collect(); } System.Console.WriteLine("Got to changelist " + x.ToString()); System.Threading.Thread.Sleep(100); } } } If I'm mishandling memory in either scenario, if there's something I should spot with a profiler, let me know. That's a pretty simple routine there. Unfortunately, it looks like @Kevin's answer is right-- this is a bug in .NET and how .NET handles objects larger than 85k. This situation strikes me as exceedingly strange; could Powerpoint be rewritten in .NET with this kind of limitation, or any of the other Office suite applications? 85k does not seem to me to be a whole lot of space, and I'd also think that any program that uses so-called 'large' allocations frequently would become unstable within a matter of days to weeks when using .NET. EDIT: It looks like Kevin is right, this is a limitation of .NET's GC. For those who don't want to follow the entire thread, .NET has four GC heaps: gen0, gen1, gen2, and LOH (Large Object Heap). Everything that's 85k or smaller goes on one of the first three heaps, depending on creation time (moved from gen0 to gen1 to gen2, etc). Objects larger than 85k get placed on the LOH. The LOH is never compacted, so eventually, allocations of the type I'm doing will eventually cause an OOM error as objects get scattered about that memory space. We've found that moving to .NET 4.0 does help the problem somewhat, delaying the exception, but not preventing it. To be honest, this feels a bit like the 640k barrier-- 85k ought to be enough for any user application (to paraphrase this video of a discussion of the GC in .NET). For the record, Java does not exhibit this behavior with its GC.

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• Setting an XAML Window always on top (but no TopMost property)

  - by Brian Scherady

  I am developing an application based on OptiTrack SDK (from NaturalPoint). I need to run the application window as "Always on Top". The window is designed in XAML and is controled in the class "CameraView" but it does not seem to include a "TopMost" property or equivalent. Attached are the code of "CameraView.xaml.cs" and the code of "CameraView.xaml" that are part of OptiTrack SDK (NaturalPoint) called "Single_Camera_CSharp_.NET_3.0". One could expect the class CameraView to contain properties or members to set the position of the window on the screen or to set it to TopMost but as far as searched I found nothing. I wonder what I should do. Thank you, Brian ================ "CameraView.xaml.cs" using System; using System.IO; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Navigation; using System.Drawing.Imaging; using System.Drawing.Drawing2D; using System.Windows.Threading; namespace TestProject { public partial class CameraView { private const int NP_OPTION_OBJECT_COLOR_OPTION = 3; private const int NP_OPTION_VIDEO_TYPE = 48; private const int NP_OPTION_NUMERIC_DISPLAY_ON = 71; private const int NP_OPTION_NUMERIC_DISPLAY_OFF = 72; private const int NP_OPTION_FETCH_RLE = 73; private const int NP_OPTION_FETCH_GRAYSCALE = 74; private const int NP_OPTION_FRAME_DECIMATION = 52; private const int NP_OPTION_INTENSITY = 50; private const int NP_OPTION_SEND_EMPTY_FRAMES = 41; private const int NP_OPTION_THRESHOLD = 5; private const int NP_OPTION_EXPOSURE = 46; private const int NP_OPTION_SEND_FRAME_MASK = 73; private const int NP_OPTION_TEXT_OVERLAY_OPTION = 74; // public delegate void OnCameraViewCreate(CameraView camera); // public static OnCameraViewCreate onCameraViewCreate; private System.Drawing.Bitmap raw = new System.Drawing.Bitmap(353, 288, System.Drawing.Imaging.PixelFormat.Format32bppArgb); private int mFrameCounter; private int mDisplayCounter; private DispatcherTimer timer1 = new DispatcherTimer(); private bool mVideoFrameAvailable = false; private int mNumeric = -1; private bool mGreyscale = false; private bool mOverlay = true; public CameraView() { this.InitializeComponent(); timer1.Interval = new TimeSpan(0, 0, 0, 0, 10); timer1.Tick += new EventHandler(timer1_Tick); } public int Numeric { get { return mNumeric; } set { mNumeric = value % 100; if (mNumeric = 0) { if (Camera != null) Camera.SetOption(NP_OPTION_NUMERIC_DISPLAY_ON, value % 100); } } } private bool CameraRunning = false; private OptiTrack.NPCamera mCamera; public OptiTrack.NPCamera Camera { get { return mCamera; } set { if (mCamera == value) return; //== Don't do anything if you're assigning the same camera == if (mCamera != null) { //== Shut the selected camera down ==<< if (CameraRunning) { CameraRunning = false; mCamera.Stop(); mCamera.FrameAvailable -= FrameAvailable; } } mCamera = value; if (mCamera == null) { mNumeric = -1; } else { serialLabel.Content = "Camera "+mCamera.SerialNumber.ToString(); //mNumeric.ToString(); } } } private void FrameAvailable(OptiTrack.NPCamera Camera) { mFrameCounter++; try { OptiTrack.NPCameraFrame frame = Camera.GetFrame(0); int id = frame.Id; if (CameraRunning) { GetFrameData(Camera, frame); } frame.Free(); } catch (Exception) { int r = 0; r++; } } private void GetFrameData(OptiTrack.NPCamera camera, OptiTrack.NPCameraFrame frame) { BitmapData bmData = raw.LockBits(new System.Drawing.Rectangle(0, 0, raw.Width, raw.Height), ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppArgb); int stride = bmData.Stride; System.IntPtr bufferPtr = bmData.Scan0; unsafe { byte* buffer = (byte*)(void*)bufferPtr; camera.GetFrameImage(frame, bmData.Width, bmData.Height, bmData.Stride, 32, ref buffer[0]); } raw.UnlockBits(bmData); mVideoFrameAvailable = true; } private void timer1_Tick(object sender, EventArgs e) { if (CameraRunning && mVideoFrameAvailable) { mVideoFrameAvailable = false; cameraImage.Source = Img(raw); mDisplayCounter++; } } private System.Windows.Media.ImageSource Img(System.Drawing.Bitmap img) { System.Drawing.Imaging.BitmapData bmData = img.LockBits(new System.Drawing.Rectangle(0, 0, img.Width, img.Height), System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppPArgb); System.Windows.Media.Imaging.BitmapSource bitmap = System.Windows.Media.Imaging.BitmapSource.Create( img.Width, img.Height, 96, 96, PixelFormats.Bgra32, System.Windows.Media.Imaging.BitmapPalettes.WebPalette, bmData.Scan0, bmData.Stride * bmData.Height, bmData.Stride); img.UnlockBits(bmData); return bitmap; } private void startStopButton_Click(object sender, RoutedEventArgs e) { if (CameraRunning) StopCamera(); else StartCamera(); } public void StartCamera() { if (Camera != null) { mFrameCounter = 0; mDisplayCounter = 0; Camera.FrameAvailable += FrameAvailable; Camera.SetOption(NP_OPTION_VIDEO_TYPE, 0); Camera.SetOption(NP_OPTION_FRAME_DECIMATION, 1); Camera.SetOption(NP_OPTION_INTENSITY, 0); Camera.SetOption(NP_OPTION_EXPOSURE, 10); Camera.SetOption(NP_OPTION_THRESHOLD, 50); Camera.SetOption(NP_OPTION_OBJECT_COLOR_OPTION, 0); SetOverlayOption(); SetGreyscaleOption(); timer1.Start(); Camera.Start(); CameraRunning = true; this.Numeric = mNumeric; startStopButton.Content = "Stop Camera"; } } private void SetGreyscaleOption() { if(mGreyscale) Camera.SetOption(NP_OPTION_VIDEO_TYPE, 1); else Camera.SetOption(NP_OPTION_VIDEO_TYPE, 0); } private void SetOverlayOption() { if(mOverlay) Camera.SetOption(NP_OPTION_TEXT_OVERLAY_OPTION, 255); else Camera.SetOption(NP_OPTION_TEXT_OVERLAY_OPTION, 0); } public void StopCamera() { if (Camera != null) { Camera.Stop(); timer1.Stop(); CameraRunning = false; Camera.FrameAvailable -= FrameAvailable; Camera.SetOption(NP_OPTION_NUMERIC_DISPLAY_OFF, 0); startStopButton.Content = "Start Camera"; } } private void greyscaleButton_Click(object sender, RoutedEventArgs e) { if(mGreyscale) mGreyscale = false; else mGreyscale = true; SetGreyscaleOption(); } private void OverlayButton_Click(object sender, RoutedEventArgs e) { if(mOverlay) mOverlay = false; else mOverlay = true; SetOverlayOption(); } private void exposureSlider_ValueChanged(object sender, RoutedEventArgs e) { if (mCamera!=null) { mCamera.SetOption(NP_OPTION_EXPOSURE, (int) this.exposureSlider.Value); } } private void thresholdSlider_ValueChanged(object sender, RoutedEventArgs e) { if (mCamera != null) { mCamera.SetOption(NP_OPTION_THRESHOLD, (int)this.thresholdSlider.Value); } } private void optionsButton_Click(object sender, RoutedEventArgs e) { if (!propertyPanel.IsVisible) propertyPanel.Visibility = Visibility.Visible; else propertyPanel.Visibility = Visibility.Collapsed; } } } ================ "CameraView.xaml"

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• Segmentation fault in my C program

  - by user233542

  I don't understand why this would give me a seg fault. Any ideas? This is the function that returns the signal to stop the program (plus the other function that is called within this): double bisect(double A0,double A1,double Sol[N],double tol,double c) { double Amid,shot; while (A1-A0 > tol) { Amid = 0.5*(A0+A1); shot = shoot(Sol, Amid, c); if (shot==2.*Pi) { return Amid; } if (shot > 2.*Pi){ A1 = Amid; } else if (shot < 2.*Pi){ A0 = Amid; } } return 0.5*(A1+A0); } double shoot(double Sol[N],double A,double c) { int i,j; /*Initial Conditions*/ for (i=0;i<buff;i++) { Sol[i] = 0.; } for (i=buff+l;i<N;i++) { Sol[i] = 2.*Pi; } Sol[buff]= 0; Sol[buff+1]= A*exp(sqrt(1+3*c)*dx); for (i=buff+2;i<buff+l;i++) { Sol[i] = (dx*dx)*( sin(Sol[i-1]) + c*sin(3.*(Sol[i-1])) ) - Sol[i-2] + 2.*Sol[i-1]; } return Sol[i-1]; } The values buff, l, N are defined using a #define statement. l = 401, buff = 50, N = 2000 Here is the full code: #include <stdio.h> #include <stdlib.h> #include <math.h> #define w 10 /*characteristic width of a soliton*/ #define dx 0.05 /*distance between lattice sites*/ #define s (2*w)/dx /*size of soliton shape*/ #define l (int)(s+1) /*array length for soliton*/ #define N (int)2000 /*length of field array--lattice sites*/ #define Pi (double)4*atan(1) #define buff (int)50 double shoot(double Sol[N],double A,double c); double bisect(double A0,double A1,double Sol[N],double tol,double c); void super_pos(double antiSol[N],double Sol[N],double phi[][N]); void vel_ver(double phi[][N],double v,double c,int tsteps,double dt); int main(int argc, char **argv) { double c,Sol[N],antiSol[N],A,A0,A1,tol,v,dt; int tsteps,i; FILE *fp1,*fp2,*fp3; fp1 = fopen("soliton.dat","w"); fp2 = fopen("final-phi.dat","w"); fp3 = fopen("energy.dat","w"); printf("Please input the number of time steps:"); scanf("%d",&tsteps); printf("Also, enter the time step size:"); scanf("%lf",&dt); do{ printf("Please input the parameter c in the interval [-1/3,1]:"); scanf("%lf",&c);} while(c < (-1./3.) || c > 1.); printf("Please input the inital speed of eiter soliton:"); scanf("%lf",&v); double phi[tsteps+1][N]; tol = 0.0000001; A0 = 0.; A1 = 2.*Pi; A = bisect(A0,A1,Sol,tol,c); shoot(Sol,A,c); for (i=0;i<N;i++) { fprintf(fp1,"%d\t",i); fprintf(fp1,"%lf\n",Sol[i]); } fclose(fp1); super_pos(antiSol,Sol,phi); /*vel_ver(phi,v,c,tsteps,dt); for (i=0;i<N;i++){ fprintf(fp2,"%d\t",i); fprintf(fp2,"%lf\n",phi[tsteps][i]); }*/ } double shoot(double Sol[N],double A,double c) { int i,j; /*Initial Conditions*/ for (i=0;i<buff;i++) { Sol[i] = 0.; } for (i=buff+l;i<N;i++) { Sol[i] = 2.*Pi; } Sol[buff]= 0; Sol[buff+1]= A*exp(sqrt(1+3*c)*dx); for (i=buff+2;i<buff+l;i++) { Sol[i] = (dx*dx)*( sin(Sol[i-1]) + c*sin(3.*(Sol[i-1])) ) - Sol[i-2] + 2.*Sol[i-1]; } return Sol[i-1]; } double bisect(double A0,double A1,double Sol[N],double tol,double c) { double Amid,shot; while (A1-A0 > tol) { Amid = 0.5*(A0+A1); shot = shoot(Sol, Amid, c); if (shot==2.*Pi) { return Amid; } if (shot > 2.*Pi){ A1 = Amid; } else if (shot < 2.*Pi){ A0 = Amid; } } return 0.5*(A1+A0); } void super_pos(double antiSol[N],double Sol[N],double phi[][N]) { int i; /*for (i=0;i<N;i++) { phi[i]=0; } for (i=buffer+s;i<1950-s;i++) { phi[i]=2*Pi; }*/ for (i=0;i<N;i++) { antiSol[i] = Sol[N-i]; } /*for (i=0;i<s+1;i++) { phi[buffer+j] = Sol[j]; phi[1549+j] = antiSol[j]; }*/ for (i=0;i<N;i++) { phi[0][i] = antiSol[i] + Sol[i] - 2.*Pi; } } /* This funciton will set the 2nd input array to the derivative at the time t, for all points x in the lattice */ void deriv2(double phi[][N],double DphiDx2[][N],int t) { //double SolDer2[s+1]; int x; for (x=0;x<N;x++) { DphiDx2[t][x] = (phi[buff+x+1][t] + phi[buff+x-1][t] - 2.*phi[x][t])/(dx*dx); } /*for (i=0;i<N;i++) { ptr[i] = &SolDer2[i]; }*/ //return DphiDx2[x]; } void vel_ver(double phi[][N],double v,double c,int tsteps,double dt) { int t,x; double d1,d2,dp,DphiDx1[tsteps+1][N],DphiDx2[tsteps+1][N],dpdt[tsteps+1][N],p[tsteps+1][N]; for (t=0;t<tsteps;t++){ if (t==0){ for (x=0;x<N;x++){//inital conditions deriv2(phi,DphiDx2,t); dpdt[t][x] = DphiDx2[t][x] - sin(phi[t][x]) - sin(3.*phi[t][x]); DphiDx1[t][x] = (phi[t][x+1] - phi[t][x])/dx; p[t][x] = -v*DphiDx1[t][x]; } } for (x=0;x<N;x++){//velocity-verlet phi[t+1][x] = phi[t][x] + dt*p[t][x] + (dt*dt/2)*dpdt[t][x]; p[t+1][x] = p[t][x] + (dt/2)*dpdt[t][x]; deriv2(phi,DphiDx2,t+1); dpdt[t][x] = DphiDx2[t][x] - sin(phi[t+1][x]) - sin(3.*phi[t+1][x]); p[t+1][x] += (dt/2)*dpdt[t+1][x]; } } } So, this really isn't due to my overwriting the end of the Sol array. I've commented out both functions that I suspected of causing the problem (bisect or shoot) and inserted a print function. Two things happen. When I have code like below: double A,Pi,B,c; c=0; Pi = 4.*atan(1.); A = Pi; B = 1./4.; printf("%lf",B); B = shoot(Sol,A,c); printf("%lf",B); I get a segfault from the function, shoot. However, if I take away the shoot function so that I have: double A,Pi,B,c; c=0; Pi = 4.*atan(1.); A = Pi; B = 1./4.; printf("%lf",B); it gives me a segfault at the printf... Why!?

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• Using glDrawElements does not draw my .obj file

  - by Hallik

  I am trying to correctly import an .OBJ file from 3ds Max. I got this working using glBegin() & glEnd() from a previous question on here, but had really poor performance obviously, so I am trying to use glDrawElements now. I am importing a chessboard, its game pieces, etc. The board, each game piece, and each square on the board is stored in a struct GroupObject. The way I store the data is like this: struct Vertex { float position[3]; float texCoord[2]; float normal[3]; float tangent[4]; float bitangent[3]; }; struct Material { float ambient[4]; float diffuse[4]; float specular[4]; float shininess; // [0 = min shininess, 1 = max shininess] float alpha; // [0 = fully transparent, 1 = fully opaque] std::string name; std::string colorMapFilename; std::string bumpMapFilename; std::vector<int> indices; int id; }; //A chess piece or square struct GroupObject { std::vector<Material *> materials; std::string objectName; std::string groupName; int index; }; All vertices are triangles, so there are always 3 points. When I am looping through the faces f section in the obj file, I store the v0, v1, & v2 in the Material-indices. (I am doing v[0-2] - 1 to account for obj files being 1-based and my vectors being 0-based. So when I get to the render method, I am trying to loop through every object, which loops through every material attached to that object. I set the material information and try and use glDrawElements. However, the screen is black. I was able to draw the model just fine when I looped through each distinct material with all the indices associated with that material, and it drew the model fine. This time around, so I can use the stencil buffer for selecting GroupObjects, I changed up the loop, but the screen is black. Here is my render loop. The only thing I changed was the for loop(s) so they go through each object, and each material in the object in turn. void GLEngine::drawModel() { glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // Vertex arrays setup glEnableClientState( GL_VERTEX_ARRAY ); glVertexPointer(3, GL_FLOAT, model.getVertexSize(), model.getVertexBuffer()->position); glEnableClientState( GL_NORMAL_ARRAY ); glNormalPointer(GL_FLOAT, model.getVertexSize(), model.getVertexBuffer()->normal); glClientActiveTexture( GL_TEXTURE0 ); glEnableClientState( GL_TEXTURE_COORD_ARRAY ); glTexCoordPointer(2, GL_FLOAT, model.getVertexSize(), model.getVertexBuffer()->texCoord); glUseProgram(blinnPhongShader); objects = model.getObjects(); // Loop through objects... for( int i=0 ; i < objects.size(); i++ ) { ModelOBJ::GroupObject *object = objects[i]; // Loop through materials used by object... for( int j=0 ; j<object->materials.size() ; j++ ) { ModelOBJ::Material *pMaterial = object->materials[j]; glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, pMaterial->ambient); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, pMaterial->diffuse); glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, pMaterial->specular); glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, pMaterial->shininess * 128.0f); // Draw faces, letting OpenGL loop through them glDrawElements( GL_TRIANGLES, pMaterial->indices.size(), GL_UNSIGNED_INT, &pMaterial->indices ); } } if (model.hasNormals()) glDisableClientState(GL_NORMAL_ARRAY); if (model.hasTextureCoords()) { glClientActiveTexture(GL_TEXTURE0); glDisableClientState(GL_TEXTURE_COORD_ARRAY); } if (model.hasPositions()) glDisableClientState(GL_VERTEX_ARRAY); glBindTexture(GL_TEXTURE_2D, 0); glUseProgram(0); glDisable(GL_BLEND); } I don't know what I am missing that's important. If it's also helpful, here is where I read a 'f' face line and store the info in the obj importer in the pMaterial-indices. else if (sscanf(buffer, "%d/%d/%d", &v[0], &vt[0], &vn[0]) == 3) // v/vt/vn { fscanf(pFile, "%d/%d/%d", &v[1], &vt[1], &vn[1]); fscanf(pFile, "%d/%d/%d", &v[2], &vt[2], &vn[2]); v[0] = (v[0] < 0) ? v[0] + numVertices - 1 : v[0] - 1; v[1] = (v[1] < 0) ? v[1] + numVertices - 1 : v[1] - 1; v[2] = (v[2] < 0) ? v[2] + numVertices - 1 : v[2] - 1; currentMaterial->indices.push_back(v[0]); currentMaterial->indices.push_back(v[1]); currentMaterial->indices.push_back(v[2]); Again, this worked drawing it all together only separated by materials, so I haven't changed code anywhere else except added the indices to the materials within objects, and the loop in the draw method. Before everything was showing up black, now with the setup as above, I am getting an unhandled exception write violation on the glDrawElements line. I did a breakpoint there, and there are over 600 elements in the pMaterial-indices array, so it's not empty, it has indices to use. When I set the glDrawElements like this, it gives me the black screen but no errors glDrawElements( GL_TRIANGLES, pMaterial->indices.size(), GL_UNSIGNED_INT, &pMaterial->indices[0] ); I have also tried adding this when I loop through the faces on import if ( currentMaterial->startIndex == -1 ) currentMaterial->startIndex = v[0]; currentMaterial->triangleCount++; And when drawing... //in draw method glDrawElements( GL_TRIANGLES, pMaterial->triangleCount * 3, GL_UNSIGNED_INT, model.getIndexBuffer() + pMaterial->startIndex );

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• timer_getoverrun() doesn't behave as expected when using sleep()

  - by dlp

  Here is a program that uses a POSIX per-process timer alongside the sleep subroutine. The signal used by the timer has been set to SIGUSR1 rather than SIGALRM, since SIGALRM may be used internally by sleep, but it still doesn't seem to work. I have run the program using the command line timer-overruns -d 1 -n 10000000 (1 cs interval) so, in theory, we should expect 100 overruns between calls to sigwaitinfo. However, timer_getoverrun returns 0. I have also tried a version using a time-consuming for loop to introduce the delay. In this case, overruns are recorded. Does anyone know why this happens? I am running a 3.4 Linux kernel. Program source /* * timer-overruns.c */ #include <unistd.h> #include <stdlib.h> #include <stdio.h> #include <signal.h> #include <time.h> // Signal to be used for timer expirations #define TIMER_SIGNAL SIGUSR1 int main(int argc, char **argv) { int opt; int d = 0; int r = 0; // Repeat indefinitely struct itimerspec its; its.it_interval.tv_sec = 0; its.it_interval.tv_nsec = 0; // Parse arguments while ((opt = getopt(argc, argv, "d:r:s:n:")) != -1) { switch (opt) { case 'd': // Delay before calling sigwaitinfo() d = atoi(optarg); break; case 'r': // Number of times to call sigwaitinfo() r = atoi(optarg); break; case 's': // Timer interval (seconds) its.it_interval.tv_sec = its.it_value.tv_sec = atoi(optarg); break; case 'n': // Timer interval (nanoseconds) its.it_interval.tv_nsec = its.it_value.tv_nsec = atoi(optarg); break; default: /* '?' */ fprintf(stderr, "Usage: %s [-d signal_accept_delay] [-r repetitions] [-s interval_seconds] [-n interval_nanoseconds]\n", argv[0]); exit(EXIT_FAILURE); } } // Check sanity of command line arguments short e = 0; if (d < 0) { fprintf(stderr, "Delay (-d) cannot be negative!\n"); e++; } if (r < 0) { fprintf(stderr, "Number of repetitions (-r) cannot be negative!\n"); e++; } if (its.it_interval.tv_sec < 0) { fprintf(stderr, "Interval seconds value (-s) cannot be negative!\n"); e++; } if (its.it_interval.tv_nsec < 0) { fprintf(stderr, "Interval nanoseconds value (-n) cannot be negative!\n"); e++; } if (its.it_interval.tv_nsec > 999999999) { fprintf(stderr, "Interval nanoseconds value (-n) must be < 1 second.\n"); e++; } if (e > 0) exit(EXIT_FAILURE); // Set default values if not specified if (its.it_interval.tv_sec == 0 && its.it_interval.tv_nsec == 0) { its.it_interval.tv_sec = its.it_value.tv_sec = 1; its.it_value.tv_nsec = 0; } printf("Running with timer delay %d.%09d seconds\n", (int) its.it_interval.tv_sec, (int) its.it_interval.tv_nsec); // Will be waiting for signals synchronously, so block the one in use. sigset_t sigset; sigemptyset(&sigset); sigaddset(&sigset, TIMER_SIGNAL); sigprocmask(SIG_BLOCK, &sigset, NULL ); // Create and arm the timer struct sigevent sev; timer_t timer; sev.sigev_notify = SIGEV_SIGNAL; sev.sigev_signo = TIMER_SIGNAL; sev.sigev_value.sival_ptr = timer; timer_create(CLOCK_REALTIME, &sev, &timer); timer_settime(timer, TIMER_ABSTIME, &its, NULL ); // Signal handling loop int overruns; siginfo_t si; // Make the loop infinite if r = 0 if (r == 0) r = -1; while (r != 0) { // Sleeping should cause overruns if (d > 0) sleep(d); sigwaitinfo(&sigset, &si); // Check that the signal is from the timer if (si.si_code != SI_TIMER) continue; overruns = timer_getoverrun(timer); if (overruns > 0) { printf("Timer overrun occurred for %d expirations.\n", overruns); } // Decrement r if not repeating indefinitely if (r > 0) r--; } return EXIT_SUCCESS; }

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• SQL Server 2012 - AlwaysOn

  - by Claus Jandausch

  Ich war nicht nur irritiert, ich war sogar regelrecht schockiert - und für einen kurzen Moment sprachlos (was nur selten der Fall ist). Gerade eben hatte mich jemand gefragt "Wann Oracle denn etwas Vergleichbares wie AlwaysOn bieten würde - und ob überhaupt?" War ich hier im falschen Film gelandet? Ich konnte nicht anders, als meinen Unmut kundzutun und zu erklären, dass die Fragestellung normalerweise anders herum läuft. Zugegeben - es mag vielleicht strittige Punkte geben im Vergleich zwischen Oracle und SQL Server - bei denen nicht unbedingt immer Oracle die Nase vorn haben muss - aber das Thema Clustering für Hochverfügbarkeit (HA), Disaster Recovery (DR) und Skalierbarkeit gehört mit Sicherheit nicht dazu. Dieses Erlebnis hakte ich am Nachgang als Einzelfall ab, der so nie wieder vorkommen würde. Bis ich kurz darauf eines Besseren belehrt wurde und genau die selbe Frage erneut zu hören bekam. Diesmal sogar im Exadata-Umfeld und einem Oracle Stretch Cluster. Einmal ist keinmal, doch zweimal ist einmal zu viel... Getreu diesem alten Motto war mir klar, dass man das so nicht länger stehen lassen konnte. Ich habe keine Ahnung, wie die Microsoft Marketing Abteilung es geschafft hat, unter dem AlwaysOn Brading eine innovative Technologie vermuten zu lassen - aber sie hat ihren Job scheinbar gut gemacht. Doch abgesehen von einem guten Marketing, stellt sich natürlich die Frage, was wirklich dahinter steckt und wie sich das Ganze mit Oracle vergleichen lässt - und ob überhaupt? Damit wären wir wieder bei der ursprünglichen Frage angelangt.  So viel zum Hintergrund dieses Blogbeitrags - von meiner Antwort handelt der restliche Blog. "Windows was the God ..." Um den wahren Unterschied zwischen Oracle und Microsoft verstehen zu können, muss man zunächst das bedeutendste Microsoft Dogma kennen. Es lässt sich schlicht und einfach auf den Punkt bringen: "Alles muss auf Windows basieren." Die Überschrift dieses Absatzes ist kein von mir erfundener Ausspruch, sondern ein Zitat. Konkret stammt es aus einem längeren Artikel von Kurt Eichenwald in der Vanity Fair aus dem August 2012. Er lautet Microsoft's Lost Decade und sei jedem ans Herz gelegt, der die "Microsoft-Maschinerie" unter Steve Ballmer und einige ihrer Kuriositäten besser verstehen möchte. "YOU TALKING TO ME?" Microsoft C.E.O. Steve Ballmer bei seiner Keynote auf der 2012 International Consumer Electronics Show in Las Vegas am 9. Januar   Manche Dinge in diesem Artikel mögen überspitzt dargestellt erscheinen - sind sie aber nicht. Vieles davon kannte ich bereits aus eigener Erfahrung und kann es nur bestätigen. Anderes hat sich mir erst so richtig erschlossen. Insbesondere die folgenden Passagen führten zum Aha-Erlebnis: “Windows was the god—everything had to work with Windows,” said Stone... “Every little thing you want to write has to build off of Windows (or other existing roducts),” one software engineer said. “It can be very confusing, …” Ich habe immer schon darauf hingewiesen, dass in einem SQL Server Failover Cluster die Microsoft Datenbank eigentlich nichts Nenneswertes zum Geschehen beiträgt, sondern sich voll und ganz auf das Windows Betriebssystem verlässt. Deshalb muss man auch die Windows Server Enterprise Edition installieren, soll ein Failover Cluster für den SQL Server eingerichtet werden. Denn hier werden die Cluster Services geliefert - nicht mit dem SQL Server. Er ist nur lediglich ein weiteres Server Produkt, für das Windows in Ausfallszenarien genutzt werden kann - so wie Microsoft Exchange beispielsweise, oder Microsoft SharePoint, oder irgendein anderes Server Produkt das auf Windows gehostet wird. Auch Oracle kann damit genutzt werden. Das Stichwort lautet hier: Oracle Failsafe. Nur - warum sollte man das tun, wenn gleichzeitig eine überlegene Technologie wie die Oracle Real Application Clusters (RAC) zur Verfügung steht, die dann auch keine Windows Enterprise Edition voraussetzen, da Oracle die eigene Clusterware liefert. Welche darüber hinaus für kürzere Failover-Zeiten sorgt, da diese Cluster-Technologie Datenbank-integriert ist und sich nicht auf "Dritte" verlässt. Wenn man sich also schon keine technischen Vorteile mit einem SQL Server Failover Cluster erkauft, sondern zusätzlich noch versteckte Lizenzkosten durch die Lizenzierung der Windows Server Enterprise Edition einhandelt, warum hat Microsoft dann in den vergangenen Jahren seit SQL Server 2000 nicht ebenfalls an einer neuen und innovativen Lösung gearbeitet, die mit Oracle RAC mithalten kann? Entwickler hat Microsoft genügend? Am Geld kann es auch nicht liegen? Lesen Sie einfach noch einmal die beiden obenstehenden Zitate und sie werden den Grund verstehen. Anders lässt es sich ja auch gar nicht mehr erklären, dass AlwaysOn aus zwei unterschiedlichen Technologien besteht, die beide jedoch wiederum auf dem Windows Server Failover Clustering (WSFC) basieren. Denn daraus ergeben sich klare Nachteile - aber dazu später mehr. Um AlwaysOn zu verstehen, sollte man sich zunächst kurz in Erinnerung rufen, was Microsoft bisher an HA/DR (High Availability/Desaster Recovery) Lösungen für SQL Server zur Verfügung gestellt hat. Replikation Basiert auf logischer Replikation und Pubisher/Subscriber Architektur Transactional Replication Merge Replication Snapshot Replication Microsoft's Replikation ist vergleichbar mit Oracle GoldenGate. Oracle GoldenGate stellt jedoch die umfassendere Technologie dar und bietet High Performance. Log Shipping Microsoft's Log Shipping stellt eine einfache Technologie dar, die vergleichbar ist mit Oracle Managed Recovery in Oracle Version 7. Das Log Shipping besitzt folgende Merkmale: Transaction Log Backups werden von Primary nach Secondary/ies geschickt Einarbeitung (z.B. Restore) auf jedem Secondary individuell Optionale dritte Server Instanz (Monitor Server) für Überwachung und Alarm Log Restore Unterbrechung möglich für Read-Only Modus (Secondary) Keine Unterstützung von Automatic Failover Database Mirroring Microsoft's Database Mirroring wurde verfügbar mit SQL Server 2005, sah aus wie Oracle Data Guard in Oracle 9i, war funktional jedoch nicht so umfassend. Für ein HA/DR Paar besteht eine 1:1 Beziehung, um die produktive Datenbank (Principle DB) abzusichern. Auf der Standby Datenbank (Mirrored DB) werden alle Insert-, Update- und Delete-Operationen nachgezogen. Modi Synchron (High-Safety Modus) Asynchron (High-Performance Modus) Automatic Failover Unterstützt im High-Safety Modus (synchron) Witness Server vorausgesetzt     Zur Frage der Kontinuität Es stellt sich die Frage, wie es um diesen Technologien nun im Zusammenhang mit SQL Server 2012 bestellt ist. Unter Fanfaren seinerzeit eingeführt, war Database Mirroring das erklärte Mittel der Wahl. Ich bin kein Produkt Manager bei Microsoft und kann hierzu nur meine Meinung äußern, aber zieht man den SQL AlwaysOn Team Blog heran, so sieht es nicht gut aus für das Database Mirroring - zumindest nicht langfristig. "Does AlwaysOn Availability Group replace Database Mirroring going forward?” “The short answer is we recommend that you migrate from the mirroring configuration or even mirroring and log shipping configuration to using Availability Group. Database Mirroring will still be available in the Denali release but will be phased out over subsequent releases. Log Shipping will continue to be available in future releases.” Damit wären wir endlich beim eigentlichen Thema angelangt. Was ist eine sogenannte Availability Group und was genau hat es mit der vielversprechend klingenden Bezeichnung AlwaysOn auf sich?   SQL Server 2012 - AlwaysOn Zwei HA-Features verstekcne sich hinter dem “AlwaysOn”-Branding. Einmal das AlwaysOn Failover Clustering aka SQL Server Failover Cluster Instances (FCI) - zum Anderen die AlwaysOn Availability Groups. Failover Cluster Instances (FCI) Entspricht ungefähr dem Stretch Cluster Konzept von Oracle Setzt auf Windows Server Failover Clustering (WSFC) auf Bietet HA auf Instanz-Ebene AlwaysOn Availability Groups (Verfügbarkeitsgruppen) Ähnlich der Idee von Consistency Groups, wie in Storage-Level Replikations-Software von z.B. EMC SRDF Abhängigkeiten zu Windows Server Failover Clustering (WSFC) Bietet HA auf Datenbank-Ebene   Hinweis: Verwechseln Sie nicht eine SQL Server Datenbank mit einer Oracle Datenbank. Und auch nicht eine Oracle Instanz mit einer SQL Server Instanz. Die gleichen Begriffe haben hier eine andere Bedeutung - nicht selten ein Grund, weshalb Oracle- und Microsoft DBAs schnell aneinander vorbei reden. Denken Sie bei einer SQL Server Datenbank eher an ein Oracle Schema, das kommt der Sache näher. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Wenn Sie die genauen Unterschiede kennen möchten, finden Sie eine detaillierte Beschreibung in meinem Buch "Oracle10g Release 2 für Windows und .NET", erhältich bei Lehmanns, Amazon, etc.   Windows Server Failover Clustering (WSFC) Wie man sieht, basieren beide AlwaysOn Technologien wiederum auf dem Windows Server Failover Clustering (WSFC), um einerseits Hochverfügbarkeit auf Ebene der Instanz zu gewährleisten und andererseits auf der Datenbank-Ebene. Deshalb nun eine kurze Beschreibung der WSFC. Die WSFC sind ein mit dem Windows Betriebssystem geliefertes Infrastruktur-Feature, um HA für Server Anwendungen, wie Microsoft Exchange, SharePoint, SQL Server, etc. zu bieten. So wie jeder andere Cluster, besteht ein WSFC Cluster aus einer Gruppe unabhängiger Server, die zusammenarbeiten, um die Verfügbarkeit einer Applikation oder eines Service zu erhöhen. Falls ein Cluster-Knoten oder -Service ausfällt, kann der auf diesem Knoten bisher gehostete Service automatisch oder manuell auf einen anderen im Cluster verfügbaren Knoten transferriert werden - was allgemein als Failover bekannt ist. Unter SQL Server 2012 verwenden sowohl die AlwaysOn Avalability Groups, als auch die AlwaysOn Failover Cluster Instances die WSFC als Plattformtechnologie, um Komponenten als WSFC Cluster-Ressourcen zu registrieren. Verwandte Ressourcen werden in eine Ressource Group zusammengefasst, die in Abhängigkeit zu anderen WSFC Cluster-Ressourcen gebracht werden kann. Der WSFC Cluster Service kann jetzt die Notwendigkeit zum Neustart der SQL Server Instanz erfassen oder einen automatischen Failover zu einem anderen Server-Knoten im WSFC Cluster auslösen.   Failover Cluster Instances (FCI) Eine SQL Server Failover Cluster Instanz (FCI) ist eine einzelne SQL Server Instanz, die in einem Failover Cluster betrieben wird, der aus mehreren Windows Server Failover Clustering (WSFC) Knoten besteht und so HA (High Availability) auf Ebene der Instanz bietet. Unter Verwendung von Multi-Subnet FCI kann auch Remote DR (Disaster Recovery) unterstützt werden. Eine weitere Option für Remote DR besteht darin, eine unter FCI gehostete Datenbank in einer Availability Group zu betreiben. Hierzu später mehr. FCI und WSFC Basis FCI, das für lokale Hochverfügbarkeit der Instanzen genutzt wird, ähnelt der veralteten Architektur eines kalten Cluster (Aktiv-Passiv). Unter SQL Server 2008 wurde diese Technologie SQL Server 2008 Failover Clustering genannt. Sie nutzte den Windows Server Failover Cluster. In SQL Server 2012 hat Microsoft diese Basistechnologie unter der Bezeichnung AlwaysOn zusammengefasst. Es handelt sich aber nach wie vor um die klassische Aktiv-Passiv-Konfiguration. Der Ablauf im Failover-Fall ist wie folgt: Solange kein Hardware-oder System-Fehler auftritt, werden alle Dirty Pages im Buffer Cache auf Platte geschrieben Alle entsprechenden SQL Server Services (Dienste) in der Ressource Gruppe werden auf dem aktiven Knoten gestoppt Die Ownership der Ressource Gruppe wird auf einen anderen Knoten der FCI transferriert Der neue Owner (Besitzer) der Ressource Gruppe startet seine SQL Server Services (Dienste) Die Connection-Anforderungen einer Client-Applikation werden automatisch auf den neuen aktiven Knoten mit dem selben Virtuellen Network Namen (VNN) umgeleitet Abhängig vom Zeitpunkt des letzten Checkpoints, kann die Anzahl der Dirty Pages im Buffer Cache, die noch auf Platte geschrieben werden müssen, zu unvorhersehbar langen Failover-Zeiten führen. Um diese Anzahl zu drosseln, besitzt der SQL Server 2012 eine neue Fähigkeit, die Indirect Checkpoints genannt wird. Indirect Checkpoints ähnelt dem Fast-Start MTTR Target Feature der Oracle Datenbank, das bereits mit Oracle9i verfügbar war.   SQL Server Multi-Subnet Clustering Ein SQL Server Multi-Subnet Failover Cluster entspricht vom Konzept her einem Oracle RAC Stretch Cluster. Doch dies ist nur auf den ersten Blick der Fall. Im Gegensatz zu RAC ist in einem lokalen SQL Server Failover Cluster jeweils nur ein Knoten aktiv für eine Datenbank. Für die Datenreplikation zwischen geografisch entfernten Sites verlässt sich Microsoft auf 3rd Party Lösungen für das Storage Mirroring.     Die Verbesserung dieses Szenario mit einer SQL Server 2012 Implementierung besteht schlicht darin, dass eine VLAN-Konfiguration (Virtual Local Area Network) nun nicht mehr benötigt wird, so wie dies bisher der Fall war. Das folgende Diagramm stellt dar, wie der Ablauf mit SQL Server 2012 gehandhabt wird. In Site A und Site B wird HA jeweils durch einen lokalen Aktiv-Passiv-Cluster sichergestellt.     Besondere Aufmerksamkeit muss hier der Konfiguration und dem Tuning geschenkt werden, da ansonsten völlig inakzeptable Failover-Zeiten resultieren. Dies liegt darin begründet, weil die Downtime auf Client-Seite nun nicht mehr nur von der reinen Failover-Zeit abhängt, sondern zusätzlich von der Dauer der DNS Replikation zwischen den DNS Servern. (Rufen Sie sich in Erinnerung, dass wir gerade von Multi-Subnet Clustering sprechen). Außerdem ist zu berücksichtigen, wie schnell die Clients die aktualisierten DNS Informationen abfragen. Spezielle Konfigurationen für Node Heartbeat, HostRecordTTL (Host Record Time-to-Live) und Intersite Replication Frequeny für Active Directory Sites und Services werden notwendig. Default TTL für Windows Server 2008 R2: 20 Minuten Empfohlene Einstellung: 1 Minute DNS Update Replication Frequency in Windows Umgebung: 180 Minuten Empfohlene Einstellung: 15 Minuten (minimaler Wert)   Betrachtet man diese Werte, muss man feststellen, dass selbst eine optimale Konfiguration die rigiden SLAs (Service Level Agreements) heutiger geschäftskritischer Anwendungen für HA und DR nicht erfüllen kann. Denn dies impliziert eine auf der Client-Seite erlebte Failover-Zeit von insgesamt 16 Minuten. Hierzu ein Auszug aus der SQL Server 2012 Online Dokumentation: Cons: If a cross-subnet failover occurs, the client recovery time could be 15 minutes or longer, depending on your HostRecordTTL setting and the setting of your cross-site DNS/AD replication schedule.    Wir sind hier an einem Punkt unserer Überlegungen angelangt, an dem sich erklärt, weshalb ich zuvor das "Windows was the God ..." Zitat verwendet habe. Die unbedingte Abhängigkeit zu Windows wird zunehmend zum Problem, da sie die Komplexität einer Microsoft-basierenden Lösung erhöht, anstelle sie zu reduzieren. Und Komplexität ist das Letzte, was sich CIOs heutzutage wünschen.  Zur Ehrenrettung des SQL Server 2012 und AlwaysOn muss man sagen, dass derart lange Failover-Zeiten kein unbedingtes "Muss" darstellen, sondern ein "Kann". Doch auch ein "Kann" kann im unpassenden Moment unvorhersehbare und kostspielige Folgen haben. Die Unabsehbarkeit ist wiederum Ursache vieler an der Implementierung beteiligten Komponenten und deren Abhängigkeiten, wie beispielsweise drei Cluster-Lösungen (zwei von Microsoft, eine 3rd Party Lösung). Wie man die Sache auch dreht und wendet, kommt man an diesem Fakt also nicht vorbei - ganz unabhängig von der Dauer einer Downtime oder Failover-Zeiten. Im Gegensatz zu AlwaysOn und der hier vorgestellten Version eines Stretch-Clusters, vermeidet eine entsprechende Oracle Implementierung eine derartige Komplexität, hervorgerufen duch multiple Abhängigkeiten. Den Unterschied machen Datenbank-integrierte Mechanismen, wie Fast Application Notification (FAN) und Fast Connection Failover (FCF). Für Oracle MAA Konfigurationen (Maximum Availability Architecture) sind Inter-Site Failover-Zeiten im Bereich von Sekunden keine Seltenheit. Wenn Sie dem Link zur Oracle MAA folgen, finden Sie außerdem eine Reihe an Customer Case Studies. Auch dies ist ein wichtiges Unterscheidungsmerkmal zu AlwaysOn, denn die Oracle Technologie hat sich bereits zigfach in höchst kritischen Umgebungen bewährt.   Availability Groups (Verfügbarkeitsgruppen) Die sogenannten Availability Groups (Verfügbarkeitsgruppen) sind - neben FCI - der weitere Baustein von AlwaysOn.   Hinweis: Bevor wir uns näher damit beschäftigen, sollten Sie sich noch einmal ins Gedächtnis rufen, dass eine SQL Server Datenbank nicht die gleiche Bedeutung besitzt, wie eine Oracle Datenbank, sondern eher einem Oracle Schema entspricht. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema.   Eine Verfügbarkeitsgruppe setzt sich zusammen aus einem Set mehrerer Benutzer-Datenbanken, die im Falle eines Failover gemeinsam als Gruppe behandelt werden. Eine Verfügbarkeitsgruppe unterstützt ein Set an primären Datenbanken (primäres Replikat) und einem bis vier Sets von entsprechenden sekundären Datenbanken (sekundäre Replikate).       Es können jedoch nicht alle SQL Server Datenbanken einer AlwaysOn Verfügbarkeitsgruppe zugeordnet werden. Der SQL Server Spezialist Michael Otey zählt in seinem SQL Server Pro Artikel folgende Anforderungen auf: Verfügbarkeitsgruppen müssen mit Benutzer-Datenbanken erstellt werden. System-Datenbanken können nicht verwendet werden Die Datenbanken müssen sich im Read-Write Modus befinden. Read-Only Datenbanken werden nicht unterstützt Die Datenbanken in einer Verfügbarkeitsgruppe müssen Multiuser Datenbanken sein Sie dürfen nicht das AUTO_CLOSE Feature verwenden Sie müssen das Full Recovery Modell nutzen und es muss ein vollständiges Backup vorhanden sein Eine gegebene Datenbank kann sich nur in einer einzigen Verfügbarkeitsgruppe befinden und diese Datenbank düerfen nicht für Database Mirroring konfiguriert sein Microsoft empfiehl außerdem, dass der Verzeichnispfad einer Datenbank auf dem primären und sekundären Server identisch sein sollte Wie man sieht, eignen sich Verfügbarkeitsgruppen nicht, um HA und DR vollständig abzubilden. Die Unterscheidung zwischen der Instanzen-Ebene (FCI) und Datenbank-Ebene (Availability Groups) ist von hoher Bedeutung. Vor kurzem wurde mir gesagt, dass man mit den Verfügbarkeitsgruppen auf Shared Storage verzichten könne und dadurch Kosten spart. So weit so gut ... Man kann natürlich eine Installation rein mit Verfügbarkeitsgruppen und ohne FCI durchführen - aber man sollte sich dann darüber bewusst sein, was man dadurch alles nicht abgesichert hat - und dies wiederum für Desaster Recovery (DR) und SLAs (Service Level Agreements) bedeutet. Kurzum, um die Kombination aus beiden AlwaysOn Produkten und der damit verbundene Komplexität kommt man wohl in der Praxis nicht herum.    Availability Groups und WSFC AlwaysOn hängt von Windows Server Failover Clustering (WSFC) ab, um die aktuellen Rollen der Verfügbarkeitsreplikate einer Verfügbarkeitsgruppe zu überwachen und zu verwalten, und darüber zu entscheiden, wie ein Failover-Ereignis die Verfügbarkeitsreplikate betrifft. Das folgende Diagramm zeigt de Beziehung zwischen Verfügbarkeitsgruppen und WSFC:   Der Verfügbarkeitsmodus ist eine Eigenschaft jedes Verfügbarkeitsreplikats. Synychron und Asynchron können also gemischt werden: Availability Modus (Verfügbarkeitsmodus) Asynchroner Commit-Modus Primäres replikat schließt Transaktionen ohne Warten auf Sekundäres Synchroner Commit-Modus Primäres Replikat wartet auf Commit von sekundärem Replikat Failover Typen Automatic Manual Forced (mit möglichem Datenverlust) Synchroner Commit-Modus Geplanter, manueller Failover ohne Datenverlust Automatischer Failover ohne Datenverlust Asynchroner Commit-Modus Nur Forced, manueller Failover mit möglichem Datenverlust   Der SQL Server kennt keinen separaten Switchover Begriff wie in Oracle Data Guard. Für SQL Server werden alle Role Transitions als Failover bezeichnet. Tatsächlich unterstützt der SQL Server keinen Switchover für asynchrone Verbindungen. Es gibt nur die Form des Forced Failover mit möglichem Datenverlust. Eine ähnliche Fähigkeit wie der Switchover unter Oracle Data Guard ist so nicht gegeben.   SQL Sever FCI mit Availability Groups (Verfügbarkeitsgruppen) Neben den Verfügbarkeitsgruppen kann eine zweite Failover-Ebene eingerichtet werden, indem SQL Server FCI (auf Shared Storage) mit WSFC implementiert wird. Ein Verfügbarkeitesreplikat kann dann auf einer Standalone Instanz gehostet werden, oder einer FCI Instanz. Zum Verständnis: Die Verfügbarkeitsgruppen selbst benötigen kein Shared Storage. Diese Kombination kann verwendet werden für lokale HA auf Ebene der Instanz und DR auf Datenbank-Ebene durch Verfügbarkeitsgruppen. Das folgende Diagramm zeigt dieses Szenario:   Achtung! Hier handelt es sich nicht um ein Pendant zu Oracle RAC plus Data Guard, auch wenn das Bild diesen Eindruck vielleicht vermitteln mag - denn alle sekundären Knoten im FCI sind rein passiv. Es existiert außerdem eine weitere und ernsthafte Einschränkung: SQL Server Failover Cluster Instanzen (FCI) unterstützen nicht das automatische AlwaysOn Failover für Verfügbarkeitsgruppen. Jedes unter FCI gehostete Verfügbarkeitsreplikat kann nur für manuelles Failover konfiguriert werden.   Lesbare Sekundäre Replikate Ein oder mehrere Verfügbarkeitsreplikate in einer Verfügbarkeitsgruppe können für den lesenden Zugriff konfiguriert werden, wenn sie als sekundäres Replikat laufen. Dies ähnelt Oracle Active Data Guard, jedoch gibt es Einschränkungen. Alle Abfragen gegen die sekundäre Datenbank werden automatisch auf das Snapshot Isolation Level abgebildet. Es handelt sich dabei um eine Versionierung der Rows. Microsoft versuchte hiermit die Oracle MVRC (Multi Version Read Consistency) nachzustellen. Tatsächlich muss man die SQL Server Snapshot Isolation eher mit Oracle Flashback vergleichen. Bei der Implementierung des Snapshot Isolation Levels handelt sich um ein nachträglich aufgesetztes Feature und nicht um einen inhärenten Teil des Datenbank-Kernels, wie im Falle Oracle. (Ich werde hierzu in Kürze einen weiteren Blogbeitrag verfassen, wenn ich mich mit der neuen SQL Server 2012 Core Lizenzierung beschäftige.) Für die Praxis entstehen aus der Abbildung auf das Snapshot Isolation Level ernsthafte Restriktionen, derer man sich für den Betrieb in der Praxis bereits vorab bewusst sein sollte: Sollte auf der primären Datenbank eine aktive Transaktion zu dem Zeitpunkt existieren, wenn ein lesbares sekundäres Replikat in die Verfügbarkeitsgruppe aufgenommen wird, werden die Row-Versionen auf der korrespondierenden sekundären Datenbank nicht sofort vollständig verfügbar sein. Eine aktive Transaktion auf dem primären Replikat muss zuerst abgeschlossen (Commit oder Rollback) und dieser Transaktions-Record auf dem sekundären Replikat verarbeitet werden. Bis dahin ist das Isolation Level Mapping auf der sekundären Datenbank unvollständig und Abfragen sind temporär geblockt. Microsoft sagt dazu: "This is needed to guarantee that row versions are available on the secondary replica before executing the query under snapshot isolation as all isolation levels are implicitly mapped to snapshot isolation." (SQL Storage Engine Blog: AlwaysOn: I just enabled Readable Secondary but my query is blocked?)  Grundlegend bedeutet dies, dass ein aktives lesbares Replikat nicht in die Verfügbarkeitsgruppe aufgenommen werden kann, ohne das primäre Replikat vorübergehend stillzulegen. Da Leseoperationen auf das Snapshot Isolation Transaction Level abgebildet werden, kann die Bereinigung von Ghost Records auf dem primären Replikat durch Transaktionen auf einem oder mehreren sekundären Replikaten geblockt werden - z.B. durch eine lang laufende Abfrage auf dem sekundären Replikat. Diese Bereinigung wird auch blockiert, wenn die Verbindung zum sekundären Replikat abbricht oder der Datenaustausch unterbrochen wird. Auch die Log Truncation wird in diesem Zustant verhindert. Wenn dieser Zustand längere Zeit anhält, empfiehlt Microsoft das sekundäre Replikat aus der Verfügbarkeitsgruppe herauszunehmen - was ein ernsthaftes Downtime-Problem darstellt. Die Read-Only Workload auf den sekundären Replikaten kann eingehende DDL Änderungen blockieren. Obwohl die Leseoperationen aufgrund der Row-Versionierung keine Shared Locks halten, führen diese Operatioen zu Sch-S Locks (Schemastabilitätssperren). DDL-Änderungen durch Redo-Operationen können dadurch blockiert werden. Falls DDL aufgrund konkurrierender Lese-Workload blockiert wird und der Schwellenwert für 'Recovery Interval' (eine SQL Server Konfigurationsoption) überschritten wird, generiert der SQL Server das Ereignis sqlserver.lock_redo_blocked, welches Microsoft zum Kill der blockierenden Leser empfiehlt. Auf die Verfügbarkeit der Anwendung wird hierbei keinerlei Rücksicht genommen.   Keine dieser Einschränkungen existiert mit Oracle Active Data Guard.   Backups auf sekundären Replikaten  Über die sekundären Replikate können Backups (BACKUP DATABASE via Transact-SQL) nur als copy-only Backups einer vollständigen Datenbank, Dateien und Dateigruppen erstellt werden. Das Erstellen inkrementeller Backups ist nicht unterstützt, was ein ernsthafter Rückstand ist gegenüber der Backup-Unterstützung physikalischer Standbys unter Oracle Data Guard. Hinweis: Ein möglicher Workaround via Snapshots, bleibt ein Workaround. Eine weitere Einschränkung dieses Features gegenüber Oracle Data Guard besteht darin, dass das Backup eines sekundären Replikats nicht ausgeführt werden kann, wenn es nicht mit dem primären Replikat kommunizieren kann. Darüber hinaus muss das sekundäre Replikat synchronisiert sein oder sich in der Synchronisation befinden, um das Beackup auf dem sekundären Replikat erstellen zu können.   Vergleich von Microsoft AlwaysOn mit der Oracle MAA Ich komme wieder zurück auf die Eingangs erwähnte, mehrfach an mich gestellte Frage "Wann denn - und ob überhaupt - Oracle etwas Vergleichbares wie AlwaysOn bieten würde?" und meine damit verbundene (kurze) Irritation. Wenn Sie diesen Blogbeitrag bis hierher gelesen haben, dann kennen Sie jetzt meine darauf gegebene Antwort. Der eine oder andere Punkt traf dabei nicht immer auf Jeden zu, was auch nicht der tiefere Sinn und Zweck meiner Antwort war. Wenn beispielsweise kein Multi-Subnet mit im Spiel ist, sind alle diesbezüglichen Kritikpunkte zunächst obsolet. Was aber nicht bedeutet, dass sie nicht bereits morgen schon wieder zum Thema werden könnten (Sag niemals "Nie"). In manch anderes Fettnäpfchen tritt man wiederum nicht unbedingt in einer Testumgebung, sondern erst im laufenden Betrieb. Erst recht nicht dann, wenn man sich potenzieller Probleme nicht bewusst ist und keine dedizierten Tests startet. Und wer AlwaysOn erfolgreich positionieren möchte, wird auch gar kein Interesse daran haben, auf mögliche Schwachstellen und den besagten Teufel im Detail aufmerksam zu machen. Das ist keine Unterstellung - es ist nur menschlich. Außerdem ist es verständlich, dass man sich in erster Linie darauf konzentriert "was geht" und "was gut läuft", anstelle auf das "was zu Problemen führen kann" oder "nicht funktioniert". Wer will schon der Miesepeter sein? Für mich selbst gesprochen, kann ich nur sagen, dass ich lieber vorab von allen möglichen Einschränkungen wissen möchte, anstelle sie dann nach einer kurzen Zeit der heilen Welt schmerzhaft am eigenen Leib erfahren zu müssen. Ich bin davon überzeugt, dass es Ihnen nicht anders geht. Nachfolgend deshalb eine Zusammenfassung all jener Punkte, die ich im Vergleich zur Oracle MAA (Maximum Availability Architecture) als unbedingt Erwähnenswert betrachte, falls man eine Evaluierung von Microsoft AlwaysOn in Betracht zieht. 1. AlwaysOn ist eine komplexe Technologie Der SQL Server AlwaysOn Stack ist zusammengesetzt aus drei verschiedenen Technlogien: Windows Server Failover Clustering (WSFC) SQL Server Failover Cluster Instances (FCI) SQL Server Availability Groups (Verfügbarkeitsgruppen) Man kann eine derartige Lösung nicht als nahtlos bezeichnen, wofür auch die vielen von Microsoft dargestellten Einschränkungen sprechen. Während sich frühere SQL Server Versionen in Richtung eigener HA/DR Technologien entwickelten (wie Database Mirroring), empfiehlt Microsoft nun die Migration. Doch weshalb dieser Schwenk? Er führt nicht zu einem konsisten und robusten Angebot an HA/DR Technologie für geschäftskritische Umgebungen.  Liegt die Antwort in meiner These begründet, nach der "Windows was the God ..." noch immer gilt und man die Nachteile der allzu engen Kopplung mit Windows nicht sehen möchte? Entscheiden Sie selbst ... 2. Failover Cluster Instanzen - Kein RAC-Pendant Die SQL Server und Windows Server Clustering Technologie basiert noch immer auf dem veralteten Aktiv-Passiv Modell und führt zu einer Verschwendung von Systemressourcen. In einer Betrachtung von lediglich zwei Knoten erschließt sich auf Anhieb noch nicht der volle Mehrwert eines Aktiv-Aktiv Clusters (wie den Real Application Clusters), wie er von Oracle bereits vor zehn Jahren entwickelt wurde. Doch kennt man die Vorzüge der Skalierbarkeit durch einfaches Hinzufügen weiterer Cluster-Knoten, die dann alle gemeinsam als ein einziges logisches System zusammenarbeiten, versteht man was hinter dem Motto "Pay-as-you-Grow" steckt. In einem Aktiv-Aktiv Cluster geht es zwar auch um Hochverfügbarkeit - und ein Failover erfolgt zudem schneller, als in einem Aktiv-Passiv Modell - aber es geht eben nicht nur darum. An dieser Stelle sei darauf hingewiesen, dass die Oracle 11g Standard Edition bereits die Nutzung von Oracle RAC bis zu vier Sockets kostenfrei beinhaltet. Möchten Sie dazu Windows nutzen, benötigen Sie keine Windows Server Enterprise Edition, da Oracle 11g die eigene Clusterware liefert. Sie kommen in den Genuss von Hochverfügbarkeit und Skalierbarkeit und können dazu die günstigere Windows Server Standard Edition nutzen. 3. SQL Server Multi-Subnet Clustering - Abhängigkeit zu 3rd Party Storage Mirroring  Die SQL Server Multi-Subnet Clustering Architektur unterstützt den Aufbau eines Stretch Clusters, basiert dabei aber auf dem Aktiv-Passiv Modell. Das eigentlich Problematische ist jedoch, dass man sich zur Absicherung der Datenbank auf 3rd Party Storage Mirroring Technologie verlässt, ohne Integration zwischen dem Windows Server Failover Clustering (WSFC) und der darunterliegenden Mirroring Technologie. Wenn nun im Cluster ein Failover auf Instanzen-Ebene erfolgt, existiert keine Koordination mit einem möglichen Failover auf Ebene des Storage-Array. 4. Availability Groups (Verfügbarkeitsgruppen) - Vier, oder doch nur Zwei? Ein primäres Replikat erlaubt bis zu vier sekundäre Replikate innerhalb einer Verfügbarkeitsgruppe, jedoch nur zwei im Synchronen Commit Modus. Während dies zwar einen Vorteil gegenüber dem stringenten 1:1 Modell unter Database Mirroring darstellt, fällt der SQL Server 2012 damit immer noch weiter zurück hinter Oracle Data Guard mit bis zu 30 direkten Stanbdy Zielen - und vielen weiteren durch kaskadierende Ziele möglichen. Damit eignet sich Oracle Active Data Guard auch für die Bereitstellung einer Reader-Farm Skalierbarkeit für Internet-basierende Unternehmen. Mit AwaysOn Verfügbarkeitsgruppen ist dies nicht möglich. 5. Availability Groups (Verfügbarkeitsgruppen) - kein asynchrones Switchover  Die Technologie der Verfügbarkeitsgruppen wird auch als geeignetes Mittel für administrative Aufgaben positioniert - wie Upgrades oder Wartungsarbeiten. Man muss sich jedoch einem gravierendem Defizit bewusst sein: Im asynchronen Verfügbarkeitsmodus besteht die einzige Möglichkeit für Role Transition im Forced Failover mit Datenverlust! Um den Verlust von Daten durch geplante Wartungsarbeiten zu vermeiden, muss man den synchronen Verfügbarkeitsmodus konfigurieren, was jedoch ernstzunehmende Auswirkungen auf WAN Deployments nach sich zieht. Spinnt man diesen Gedanken zu Ende, kommt man zu dem Schluss, dass die Technologie der Verfügbarkeitsgruppen für geplante Wartungsarbeiten in einem derartigen Umfeld nicht effektiv genutzt werden kann. 6. Automatisches Failover - Nicht immer möglich Sowohl die SQL Server FCI, als auch Verfügbarkeitsgruppen unterstützen automatisches Failover. Möchte man diese jedoch kombinieren, wird das Ergebnis kein automatisches Failover sein. Denn ihr Zusammentreffen im Failover-Fall führt zu Race Conditions (Wettlaufsituationen), weshalb diese Konfiguration nicht länger das automatische Failover zu einem Replikat in einer Verfügbarkeitsgruppe erlaubt. Auch hier bestätigt sich wieder die tiefere Problematik von AlwaysOn, mit einer Zusammensetzung aus unterschiedlichen Technologien und der Abhängigkeit zu Windows. 7. Problematische RTO (Recovery Time Objective) Microsoft postioniert die SQL Server Multi-Subnet Clustering Architektur als brauchbare HA/DR Architektur. Bedenkt man jedoch die Problematik im Zusammenhang mit DNS Replikation und den möglichen langen Wartezeiten auf Client-Seite von bis zu 16 Minuten, sind strenge RTO Anforderungen (Recovery Time Objectives) nicht erfüllbar. Im Gegensatz zu Oracle besitzt der SQL Server keine Datenbank-integrierten Technologien, wie Oracle Fast Application Notification (FAN) oder Oracle Fast Connection Failover (FCF). 8. Problematische RPO (Recovery Point Objective) SQL Server ermöglicht Forced Failover (erzwungenes Failover), bietet jedoch keine Möglichkeit zur automatischen Übertragung der letzten Datenbits von einem alten zu einem neuen primären Replikat, wenn der Verfügbarkeitsmodus asynchron war. Oracle Data Guard hingegen bietet diese Unterstützung durch das Flush Redo Feature. Dies sichert "Zero Data Loss" und beste RPO auch in erzwungenen Failover-Situationen. 9. Lesbare Sekundäre Replikate mit Einschränkungen Aufgrund des Snapshot Isolation Transaction Level für lesbare sekundäre Replikate, besitzen diese Einschränkungen mit Auswirkung auf die primäre Datenbank. Die Bereinigung von Ghost Records auf der primären Datenbank, wird beeinflusst von lang laufenden Abfragen auf der lesabaren sekundären Datenbank. Die lesbare sekundäre Datenbank kann nicht in die Verfügbarkeitsgruppe aufgenommen werden, wenn es aktive Transaktionen auf der primären Datenbank gibt. Zusätzlich können DLL Änderungen auf der primären Datenbank durch Abfragen auf der sekundären blockiert werden. Und imkrementelle Backups werden hier nicht unterstützt.   Keine dieser Restriktionen existiert unter Oracle Data Guard.

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  - by Liu Maclean(???)

  ??????Oracle??????????row lock,??ORACLE????????????????????,row lock???????????????????????????????,??Server Process?pin????block buffer????????? ????????,?process A ??update???????? Z?????????, ???????rollback???commit;??Process B??????DML??, ???????rowid???? Z???, ???????????process A????????ITL???,????????cleanout??,????????row???????????commit, ???????Process B????”enq: TX – row lock contention”??????? ????Process B????????????? ?????????Process A???????row,??Process B???????”enq: TX – row lock contention”???? ????????  ????????: SESSION A: SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi PL/SQL Release 10.2.0.5.0 - Production CORE    10.2.0.5.0      Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> create table maclean_lock(t1 int); Table created. SQL> insert into maclean_lock values (1); 1 row created. SQL> commit; Commit complete. SQL> select dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid) from maclean_lock; DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) ------------------------------------ ------------------------------------                                67642                                    1 SQL>  select distinct sid from v$mystat;        SID ----------        142 SQL> select pid,spid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat));        PID SPID ---------- ------------         17 15636 ??SESSION A ????savepoint ,?update ?????????         SQL>  savepoint NONLOCK; Savepoint created. SQL> select * From v$Lock where sid=142; no rows selected SQL> set linesize 140 pagesize 1400 SQL>  update maclean_lock set t1=t1+2; 1 row updated. SQL> select * From v$Lock where sid=142; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 0000000091FC69F0 0000000091FC6A18        142 TM      55829          0          3          0          6          0 00000000914B4008 00000000914B4040        142 TX     393232        609          6          0          6          0         SQL> select dump(3,16) from dual; DUMP(3,16) -------------------------------------------------------------------------------- Typ=2 Len=2: c1,4 ALTER SYSTEM DUMP DATAFILE 1 BLOCK 67642;  Object id on Block? Y  seg/obj: 0xda16  csc: 0x00.234718  itc: 2  flg: O  typ: 1 - DATA      fsl: 0  fnx: 0x0 ver: 0x01  Itl           Xid                  Uba         Flag  Lck        Scn/Fsc 0x01   0x000a.00f.000001e0  0x00800075.02a6.29  C---    0  scn 0x0000.00234711 0x02   0x0007.018.000001fe  0x0080065c.017a.02  ----    1  fsc 0x0000.00000000 data_block_dump,data header at 0x81d185c =============== tsiz: 0x1fa0 hsiz: 0x14 pbl: 0x081d185c bdba: 0x0041083a      76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f9a avsp=0x1f83 tosp=0x1f83 0xe:pti[0]      nrow=1  offs=0 0x12:pri[0]     offs=0x1f9a block_row_dump: tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x2  cc: 1 col  0: [ 2]  c1 04 end_of_block_dump ?? BLOCK DUMP ???? ??????XID=0x0007.018.000001fe ?transaction?? lb:0x1 ??SESSION B ,?????UPDATE?? ???enq: TX - row lock contention ?? SQL> select distinct sid from v$mystat;        SID ----------        140 SQL> select pid,spid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat));        PID SPID ---------- ------------         24 15652 SQL> alter system set "_trace_events"='10000-10999:255:24'; System altered.         SQL> update maclean_lock set t1=t1+2; select * From v$Lock where sid=142 or sid=140 order by sid; SESSION C: SQL> select * From v$Lock where sid=142 or sid=140 order by sid; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 0000000091FC6B10 0000000091FC6B38        140 TM      55829          0          3          0         84          0 00000000924F4A58 00000000924F4A78        140 TX     458776        510          0          6         84          0 00000000914B51E8 00000000914B5220        142 TX     458776        510          6          0        312          1 0000000091FC69F0 0000000091FC6A18        142 TM      55829          0          3          0        312          0 ???? SESSION B SID=140 ?SESSION A ?TX ENQUEUE ?X mode?REQUEST SQL> oradebug dump systemstate 266; Statement processed. SESSION B waiter's enqueue lock       SO: 0x924f4a58, type: 5, owner: 0x92bb8dc8, flag: INIT/-/-/0x00       (enqueue) TX-00070018-000001FE    DID: 0001-0018-00000022       lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  res_flag: 0x6       req: X, lock_flag: 0x0, lock: 0x924f4a78, res: 0x925617c0       own: 0x92b76be0, sess: 0x92b76be0, proc: 0x92a737a0, prv: 0x925617e0 TX-00070018-000001FE=> TX 458776 510 SESSION A owner's enqueue lock       SO: 0x914b51e8, type: 40, owner: 0x92b796d0, flag: INIT/-/-/0x00       (trans) flg = 0x1e03, flg2 = 0xc0000, prx = 0x0, ros = 2147483647 bsn = 0xed5 bndsn = 0xee7 spn = 0xef7       efd = 3       file:xct.c lineno:1179       DID: 0001-0011-000000C2       parent xid: 0x0000.000.00000000       env: (scn: 0x0000.00234718  xid: 0x0007.018.000001fe  uba: 0x0080065c.017a.02  statement num=0  parent xid: xid: 0x0000.000.00000000  scn: 0x00 00.00234718 0sch: scn: 0x0000.00000000)       cev: (spc = 7818  arsp = 914e8310  ubk tsn: 1 rdba: 0x0080065c  useg tsn: 1 rdba: 0x00800069             hwm uba: 0x0080065c.017a.02  col uba: 0x00000000.0000.00             num bl: 1 bk list: 0x91435070)             cr opc: 0x0 spc: 7818 uba: 0x0080065c.017a.02       (enqueue) TX-00070018-000001FE    DID: 0001-0011-000000C2       lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  res_flag: 0x6       mode: X, lock_flag: 0x0, lock: 0x914b5220, res: 0x925617c0       own: 0x92b796d0, sess: 0x92b796d0, proc: 0x92a6ffd8, prv: 0x925617d0        xga: 0x8b7c6d40, heap: UGA       Trans IMU st: 2 Pool index 65535, Redo pool 0x914b58d0, Undo pool 0x914b59b8       Redo pool range [0x86de640 0x86de640 0x86e0e40]       Undo pool range [0x86dbe40 0x86dbe40 0x86de640]         ----------------------------------------         SO: 0x91435070, type: 39, owner: 0x914b51e8, flag: -/-/-/0x00         (List of Blocks) next index = 1         index   itli   buffer hint   rdba       savepoint         -----------------------------------------------------------             0      2   0x647f1fc8    0x41083a     0xee7 ?SESSION A? ROLLBACK ?savepoint: SQL> rollback to NONLOCK; Rollback complete. ????savepoint ??update??????? ??UPDATE???????? ROLLBACK: SQL> select * From v$Lock where sid=142 or sid=140; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 00000000924F4A58 00000000924F4A78        140 TX     458776        510          0          6        822          0 0000000091FC6B10 0000000091FC6B38        140 TM      55829          0          3          0        822          0 00000000914B51E8 00000000914B5220        142 TX     458776        510          6          0       1050          1 ???? SESSION A 142 ???SAVEPOINT ???????TM LOCK ????? ROLLBACK TO SAVEPOINT?????SESSION???TX LOCK!!!! ??????SESSION 142???TX ID1=458776 ID2=510, ????ROLLBACK TO SAVEPOINT?????????ABORT TRANSACTION ?? SESSION B  SID=140??  SESSION A ?? , ?????????SESSION B? update???HANG?? ?????????CACHE?????:  Object id on Block? Y  seg/obj: 0xda16  csc: 0x00.2347b7  itc: 2  flg: O  typ: 1 - DATA      fsl: 0  fnx: 0x0 ver: 0x01  Itl           Xid                  Uba         Flag  Lck        Scn/Fsc 0x01   0x000a.00f.000001e0  0x00800075.02a6.29  C---    0  scn 0x0000.00234711 0x02   0x0000.000.00000000  0x00000000.0000.00  ----    0  fsc 0x0000.00000000 data_block_dump,data header at 0x745d85c =============== tsiz: 0x1fa0 hsiz: 0x14 pbl: 0x0745d85c bdba: 0x0041083a      76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f9a avsp=0x1f83 tosp=0x1f83 0xe:pti[0]      nrow=1  offs=0 0x12:pri[0]     offs=0x1f9a block_row_dump: tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x0  cc: 1 col  0: [ 2]  c1 02 end_of_block_dump ???? ITL=0x02? ?????????,col  0: [ 2]  c1 02 ????????? ?????????SESSION D ,??????row lock?? ?UPDATE???????? SESSION D: SQL> update maclean_lock set t1=t1+2; 1 row updated. SQL> rollback; Rollback complete. ??SESSION B ??????????? ?????ORACLE????????, ??????????? TX lock?? row lock , ????????2??? row lock?????????, ?TX lock????????ENQUEUE LOCK???? ?????????PROCESS K?DML???????????????????????,??????????TX LOCK, ????PROCESS Z?????????????????????????ROW LOCK????????, ???????OLTP?????????????????????? ??ROW LOCK?Release ??????TX?ENQUEUE LOCK,?????????Process J ????????????, Process K??????????? ,Process K?????????,???row piece?lb??0x0 ,?????ITL, Process Z???ITL???????Process J????XID,?????Process J?????TX lock, PROCESS K ???TX resource?Enqueue Waiter Linked List?????X mode(exclusive)?enqueue lock? ???Process J??TX lock?,Process J?????TX resource?Enqueue Waiter Linked List ???Process K??????,??POST?????Process K? TX lock??????, ???????row lock???????,????????? ?????????? ?????: SESSION A ???PID =17 ?????????????????? SESSION B ???PID =24 ??????? "_trace_events"='10000-10999:255:24';  KST trace ??????? Server Process??? SESSION A PID=17  ?? acqure?SX mode???TM Lock ,?? ????Transaction?????UNDO SEGMENT 7,???XID 7.24.510, ?acquire ?X mode? TX-00070018-000001fe ? ?????? 00070018-000001fe ???? 7- 24 - 510? XID ? 781F4B8A:007A569C    17   142 10704  83 ksqgtl: acquire TM-0000da15-00000000 mode=SX flags=GLOBAL|XACT why="contention" 781F4B92:007A569D    17   142 10704  19 ksqgtl: SUCCESS 781F4BB3:007A569E    17   142 10812   2 0x000000000041083A 0x0000000000000000 0x0000000000234717 781F4BBA:007A569F    17   142 10812   3 0x0000000000000000 0x0000000000000000 0x0000000000000000 781F4BC0:007A56A0    17   142 10812   4 0x0000000000000000 0x0000000000000000 0x0000000000000000 781F4BD3:007A56A1    17   142 10812   5 0x000000000041083A 0x0000000000000000 0x0000000000000000 781F4BFE:007A56A2    17   142 10811   1 0x000000000041083A 0x0000000000000000 0x0000000000234711 0x0000000000000002 781F4C06:007A56A3    17   142 10811   2 0x000000000041083A 0x0000000000000000 0x0000000000234718 0x00007FA074EDA560 781F4C26:007A56A4    17   142 10813   1 ktubnd: Bind usn 7 nax 1 nbx 0 lng 0 par 0 781F4C43:007A56A5    17   142 10813   2 ktubnd: Txn Bound xid: 7.24.510 781F4C4A:007A56A6    17   142 10704  83 ksqgtl: acquire TX-00070018-000001fe mode=X flags=GLOBAL|XACT why="contention" 781F4C51:007A56A7    17   142 10704  19 ksqgtl: SUCCESS ?????????? ???????? 781F4CBF:007A56A8    17   142 10005   1 KSL WAIT BEG [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 781F4CCC:007A56A9    17   142 10005   2 KSL WAIT END [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 time=13 781F4CDE:007A56AA    17   142 10005   1 KSL WAIT BEG [SQL*Net message from client] 1650815232/0x62657100 1/0x1 0/0x0 786BD85D:007A57E0    17   142 10005   2 KSL WAIT END [SQL*Net message from client] 1650815232/0x62657100 1/0x1 0/0x0 time=5016447 786BD966:007A57E1    17   142 10005   1 KSL WAIT BEG [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 786BD96E:007A57E2    17   142 10005   2 KSL WAIT END [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 time=8 SESSION B ???PID =24  ,??????? SX mode? TM lock,??row lock? acquire X mode?TX-00070018-000001fe ksqgtl: acquire TM-0000da15-00000000 mode=SX flags=GLOBAL|XACT why="contention" ksqgtl: SUCCESS 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000000000001 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000008A63780 0x0000000000000001 0x0000000000800861 0x0000000000000241 0x0000000000000001 0x000000000041083A 0x0000000000000001 0x0000000000000001 0x000000000041083A 0x0000000000000000 0x00000000002354F9 0x0000000000000002 ksqgtl: acquire TX-00070018-000001fe mode=X flags=GLOBAL|LONG why="row lock contention" C4048EBD:007F52B6    24   140 10005   2 KSL WAIT END [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe time=2929879 C4048ED4:007F52B7    24   140 10005   1 KSL WAIT BEG [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe C43146CA:007F535E    24   140 10005   2 KSL WAIT END [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe time=2930676 ????????? ,PID=24 ??????ksqcmi???????? deadlock C43146D9:007F535F    24   140 10704 134 ksqcmi: performing local deadlock detection on TX-00070018-000001fe C43146F8:007F5360    24   140 10704 150 ksqcmi: deadlock not detected on TX-00070018-000001fe ?? ??? PID 17 ??ROLLBACK ???? ,????????: PID 17 ROLLBACK; D7A495BB:007F9D3E    17   142 10005   4 KSL POST SENT postee=24 loc='ksqrcl' id1=0 id2=0 name=   type=0 D7A495D8:007F9D3F    17   142 10444  12 ABORT TRANSACTION - xid: 0x0007.018.000001fe ??  PID 17 ??? TX resource?Enqueue Waiter linked List ???PID 24???,????KSL POST SENT ?? PID 24, ???ksqrcl???ENQUEUE LOCK ?PID 24??????KSL POST (KSL POST RCVD poster=17), ?ksqgtl???? TX-00070018-000001fe ?? ksqrcl??, ??PID 24???????? TX lock?USN ,??????? USN 3 XID 3.11.582 ,???acquire TX-0003000b-00000246 D7A49616:007F9D41    24   140 10005   3 KSL POST RCVD poster=17 loc='ksqrcl' id1=0 id2=0 name=   type=0 fac#=0 facpost=1 D7A4961C:007F9D42    24   140 10704  19 ksqgtl: SUCCESS D7A4967D:007F9D43    24   140 10704 117 ksqrcl: release TX-00070018-000001fe mode=X D7A496A5:007F9D44    24   140 10813   1 ktubnd: Bind usn 3 nax 1 nbx 0 lng 0 par 0 D7A496C2:007F9D45    24   140 10813   2 ktubnd: Txn Bound xid: 3.11.582 D7A496C7:007F9D46    24   140 10704  83 ksqgtl: acquire TX-0003000b-00000246 mode=X flags=GLOBAL|XACT why="contention" D7A496E4:007F9D47    24   140 10704  19 ksqgtl: SUCCESS ROW LOCK?Release ??????TX?ENQUEUE LOCK,?????????Process J ????????????, Process K??????????? ,Process K?????????,???row piece?lb??0×0 ,?????ITL,Process Z???ITL???????Process J????XID,?????Process J?????TX lock,PROCESS K ???TX resource?Enqueue Waiter Linked List?????X mode(exclusive)?enqueue lock? ???Process J??TX lock?,Process J?????TX resource?Enqueue Waiter Linked List ???Process K??????,??POST?????Process K? TX lock??????,???????row lock???????,?????????

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• FreeBSD performance tuning. Sysctls, loader.conf, kernel

  - by SaveTheRbtz

  I wanted to share knowledge of tuning FreeBSD via sysctl.conf/loader.conf/KENCONF. It was initially based on Igor Sysoev's (author of nginx) presentation about FreeBSD tuning up to 100,000-200,000 active connections. Tunings are for FreeBSD-CURRENT. Since 7.2 amd64 some of them are tuned well by default. Prior 7.0 some of them are boot only (set via /boot/loader.conf) or does not exist at all. sysctl.conf: # No zero mapping feature # May break wine # (There are also reports about broken samba3) #security.bsd.map_at_zero=0 # If you have really busy webserver with apache13 you may run out of processes #kern.maxproc=10000 # Same for servers with apache2 / Pound #kern.threads.max_threads_per_proc=4096 # Max. backlog size kern.ipc.somaxconn=4096 # Shared memory // 7.2+ can use shared memory > 2Gb kern.ipc.shmmax=2147483648 # Sockets kern.ipc.maxsockets=204800 # Can cause this on older kernels: # http://old.nabble.com/Significant-performance-regression-for-increased-maxsockbuf-on-8.0-RELEASE-tt26745981.html#a26745981 ) kern.ipc.maxsockbuf=10485760 # Mbuf 2k clusters (on amd64 7.2+ 25600 is default) # For such high value vm.kmem_size must be increased to 3G kern.ipc.nmbclusters=262144 # Jumbo pagesize(_SC_PAGESIZE) clusters # Used as general packet storage for jumbo frames # can be monitored via `netstat -m` #kern.ipc.nmbjumbop=262144 # Jumbo 9k/16k clusters # If you are using them #kern.ipc.nmbjumbo9=65536 #kern.ipc.nmbjumbo16=32768 # For lower latency you can decrease scheduler's maximum time slice # default: stathz/10 (~ 13) #kern.sched.slice=1 # Increase max command-line length showed in `ps` (e.g for Tomcat/Java) # Default is PAGE_SIZE / 16 or 256 on x86 # This avoids commands to be presented as [executable] in `ps` # For more info see: http://www.freebsd.org/cgi/query-pr.cgi?pr=120749 kern.ps_arg_cache_limit=4096 # Every socket is a file, so increase them kern.maxfiles=204800 kern.maxfilesperproc=200000 kern.maxvnodes=200000 # On some systems HPET is almost 2 times faster than default ACPI-fast # Useful on systems with lots of clock_gettime / gettimeofday calls # See http://old.nabble.com/ACPI-fast-default-timecounter,-but-HPET-83--faster-td23248172.html # After revision 222222 HPET became default: http://svnweb.freebsd.org/base?view=revision&revision=222222 kern.timecounter.hardware=HPET # Small receive space, only usable on http-server, on file server this # should be increased to 65535 or even more #net.inet.tcp.recvspace=8192 # This is useful on Fat-Long-Pipes #net.inet.tcp.recvbuf_max=10485760 #net.inet.tcp.recvbuf_inc=65535 # Small send space is useful for http servers that serve small files # Autotuned since 7.x net.inet.tcp.sendspace=16384 # This is useful on Fat-Long-Pipes #net.inet.tcp.sendbuf_max=10485760 #net.inet.tcp.sendbuf_inc=65535 # Turn off receive autotuning # You can play with it. #net.inet.tcp.recvbuf_auto=0 #net.inet.tcp.sendbuf_auto=0 # This should be enabled if you going to use big spaces (>64k) # Also timestamp field is useful when using syncookies net.inet.tcp.rfc1323=1 # Turn this off on high-speed, lossless connections (LAN 1Gbit+) # If you set it there is no need in TCP_NODELAY sockopt (see man tcp) net.inet.tcp.delayed_ack=0 # This feature is useful if you are serving data over modems, Gigabit Ethernet, # or even high speed WAN links (or any other link with a high bandwidth delay product), # especially if you are also using window scaling or have configured a large send window. # Automatically disables on small RTT ( http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_subr.c?#rev1.237 ) # This sysctl was removed in 10-CURRENT: # See: http://www.mail-archive.com/[email protected]/msg06178.html #net.inet.tcp.inflight.enable=0 # TCP slowstart algorithm tunings # We assuming we have very fast clients #net.inet.tcp.slowstart_flightsize=100 #net.inet.tcp.local_slowstart_flightsize=100 # Disable randomizing of ports to avoid false RST # Before usage check SA here www.bsdcan.org/2006/papers/ImprovingTCPIP.pdf # (it's also says that port randomization auto-disables at some conn.rates, but I didn't checked it thou) #net.inet.ip.portrange.randomized=0 # Increase portrange # For outgoing connections only. Good for seed-boxes and ftp servers. net.inet.ip.portrange.first=1024 net.inet.ip.portrange.last=65535 # # stops route cache degregation during a high-bandwidth flood # http://www.freebsd.org/doc/en/books/handbook/securing-freebsd.html #net.inet.ip.rtexpire=2 net.inet.ip.rtminexpire=2 net.inet.ip.rtmaxcache=1024 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # # There is also good example of sysctl.conf with comments: # http://www.thern.org/projects/sysctl.conf # # icmp may NOT rst, helpful for those pesky spoofed # icmp/udp floods that end up taking up your outgoing # bandwidth/ifqueue due to all that outgoing RST traffic. # #net.inet.tcp.icmp_may_rst=0 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # IPv6 Security # For more info see http://www.fosslc.org/drupal/content/security-implications-ipv6 # Disable Node info replies # To see this vulnerability in action run `ping6 -a sglAac ::1` or `ping6 -w ::1` on unprotected node net.inet6.icmp6.nodeinfo=0 # Turn on IPv6 privacy extensions # For more info see proposal http://unix.derkeiler.com/Mailing-Lists/FreeBSD/net/2008-06/msg00103.html net.inet6.ip6.use_tempaddr=1 net.inet6.ip6.prefer_tempaddr=1 # Disable ICMP redirect net.inet6.icmp6.rediraccept=0 # Disable acceptation of RA and auto linklocal generation if you don't use them #net.inet6.ip6.accept_rtadv=0 #net.inet6.ip6.auto_linklocal=0 # Increases default TTL, sometimes useful # Default is 64 net.inet.ip.ttl=128 # Lessen max segment life to conserve resources # ACK waiting time in miliseconds # (default: 30000. RFC from 1979 recommends 120000) net.inet.tcp.msl=5000 # Max bumber of timewait sockets net.inet.tcp.maxtcptw=200000 # Don't use tw on local connections # As of 15 Apr 2009. Igor Sysoev says that nolocaltimewait has some buggy realization. # So disable it or now till get fixed #net.inet.tcp.nolocaltimewait=1 # FIN_WAIT_2 state fast recycle net.inet.tcp.fast_finwait2_recycle=1 # Time before tcp keepalive probe is sent # default is 2 hours (7200000) #net.inet.tcp.keepidle=60000 # Should be increased until net.inet.ip.intr_queue_drops is zero net.inet.ip.intr_queue_maxlen=4096 # Interrupt handling via multiple CPU, but with context switch. # You can play with it. Default is 1; #net.isr.direct=0 # This is for routers only #net.inet.ip.forwarding=1 #net.inet.ip.fastforwarding=1 # This speed ups dummynet when channel isn't saturated net.inet.ip.dummynet.io_fast=1 # Increase dummynet(4) hash #net.inet.ip.dummynet.hash_size=2048 #net.inet.ip.dummynet.max_chain_len # Should be increased when you have A LOT of files on server # (Increase until vfs.ufs.dirhash_mem becomes lower) vfs.ufs.dirhash_maxmem=67108864 # Note from commit http://svn.freebsd.org/base/head@211031 : # For systems with RAID volumes and/or virtualization envirnments, where # read performance is very important, increasing this sysctl tunable to 32 # or even more will demonstratively yield additional performance benefits. vfs.read_max=32 # Explicit Congestion Notification (see http://en.wikipedia.org/wiki/Explicit_Congestion_Notification) net.inet.tcp.ecn.enable=1 # Flowtable - flow caching mechanism # Useful for routers #net.inet.flowtable.enable=1 #net.inet.flowtable.nmbflows=65535 # Extreme polling tuning #kern.polling.burst_max=1000 #kern.polling.each_burst=1000 #kern.polling.reg_frac=100 #kern.polling.user_frac=1 #kern.polling.idle_poll=0 # IPFW dynamic rules and timeouts tuning # Increase dyn_buckets till net.inet.ip.fw.curr_dyn_buckets is lower net.inet.ip.fw.dyn_buckets=65536 net.inet.ip.fw.dyn_max=65536 net.inet.ip.fw.dyn_ack_lifetime=120 net.inet.ip.fw.dyn_syn_lifetime=10 net.inet.ip.fw.dyn_fin_lifetime=2 net.inet.ip.fw.dyn_short_lifetime=10 # Make packets pass firewall only once when using dummynet # i.e. packets going thru pipe are passing out from firewall with accept #net.inet.ip.fw.one_pass=1 # shm_use_phys Wires all shared pages, making them unswappable # Use this to lessen Virtual Memory Manager's work when using Shared Mem. # Useful for databases #kern.ipc.shm_use_phys=1 # ZFS # Enable prefetch. Useful for sequential load type i.e fileserver. # FreeBSD sets vfs.zfs.prefetch_disable to 1 on any i386 systems and # on any amd64 systems with less than 4GB of avaiable memory # For additional info check this nabble thread http://old.nabble.com/Samba-read-speed-performance-tuning-td27964534.html #vfs.zfs.prefetch_disable=0 # On highload servers you may notice following message in dmesg: # "Approaching the limit on PV entries, consider increasing either the # vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable" vm.pmap.shpgperproc=2048 loader.conf: # Accept filters for data, http and DNS requests # Useful when your software uses select() instead of kevent/kqueue or when you under DDoS # DNS accf available on 8.0+ accf_data_load="YES" accf_http_load="YES" accf_dns_load="YES" # Async IO system calls aio_load="YES" # Linux specific devices in /dev # As for 8.1 it only /dev/full #lindev_load="YES" # Adds NCQ support in FreeBSD # WARNING! all ad[0-9]+ devices will be renamed to ada[0-9]+ # 8.0+ only #ahci_load="YES" #siis_load="YES" # FreeBSD 8.2+ # New Congestion Control for FreeBSD # http://caia.swin.edu.au/urp/newtcp/tools/cc_chd-readme-0.1.txt # http://www.ietf.org/proceedings/78/slides/iccrg-5.pdf # Initial merge commit message http://www.mail-archive.com/[email protected]/msg31410.html #cc_chd_load="YES" # Increase kernel memory size to 3G. # # Use ONLY if you have KVA_PAGES in kernel configuration, and you have more than 3G RAM # Otherwise panic will happen on next reboot! # # It's required for high buffer sizes: kern.ipc.nmbjumbop, kern.ipc.nmbclusters, etc # Useful on highload stateful firewalls, proxies or ZFS fileservers # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #vm.kmem_size="3G" # If your server has lots of swap (>4Gb) you should increase following value # according to http://lists.freebsd.org/pipermail/freebsd-hackers/2009-October/029616.html # Otherwise you'll be getting errors # "kernel: swap zone exhausted, increase kern.maxswzone" # kern.maxswzone="256M" # Older versions of FreeBSD can't tune maxfiles on the fly #kern.maxfiles="200000" # Useful for databases # Sets maximum data size to 1G # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #kern.maxdsiz="1G" # Maximum buffer size(vfs.maxbufspace) # You can check current one via vfs.bufspace # Should be lowered/upped depending on server's load-type # Usually decreased to preserve kmem # (default is 10% of mem) #kern.maxbcache="512M" # Sendfile buffers # For i386 only #kern.ipc.nsfbufs=10240 # FreeBSD 9+ # HPET "legacy route" support. It should allow HPET to work per-CPU # See http://www.mail-archive.com/[email protected]/msg03603.html #hint.atrtc.0.clock=0 #hint.attimer.0.clock=0 #hint.hpet.0.legacy_route=1 # syncache Hash table tuning net.inet.tcp.syncache.hashsize=1024 net.inet.tcp.syncache.bucketlimit=512 net.inet.tcp.syncache.cachelimit=65536 # Increased hostcache # Later host cache can be viewed via net.inet.tcp.hostcache.list hidden sysctl # Very useful for it's RTT RTTVAR # Must be power of two net.inet.tcp.hostcache.hashsize=65536 # hashsize * bucketlimit (which is 30 by default) # It allocates 255Mb (1966080*136) of RAM net.inet.tcp.hostcache.cachelimit=1966080 # TCP control-block Hash table tuning net.inet.tcp.tcbhashsize=4096 # Disable ipfw deny all # Should be uncommented when there is a chance that # kernel and ipfw binary may be out-of sync on next reboot #net.inet.ip.fw.default_to_accept=1 # # SIFTR (Statistical Information For TCP Research) is a kernel module that # logs a range of statistics on active TCP connections to a log file. # See prerelease notes http://groups.google.com/group/mailing.freebsd.current/browse_thread/thread/b4c18be6cdce76e4 # and man 4 sitfr #siftr_load="YES" # Enable superpages, for 7.2+ only # Also read http://lists.freebsd.org/pipermail/freebsd-hackers/2009-November/030094.html vm.pmap.pg_ps_enabled=1 # Usefull if you are using Intel-Gigabit NIC #hw.em.rxd=4096 #hw.em.txd=4096 #hw.em.rx_process_limit="-1" # Also if you have ALOT interrupts on NIC - play with following parameters # NOTE: You should set them for every NIC #dev.em.0.rx_int_delay: 250 #dev.em.0.tx_int_delay: 250 #dev.em.0.rx_abs_int_delay: 250 #dev.em.0.tx_abs_int_delay: 250 # There is also multithreaded version of em/igb drivers can be found here: # http://people.yandex-team.ru/~wawa/ # # for additional em monitoring and statistics use # sysctl dev.em.0.stats=1 ; dmesg # sysctl dev.em.0.debug=1 ; dmesg # Also after r209242 (-CURRENT) there is a separate sysctl for each stat variable; # Same tunings for igb #hw.igb.rxd=4096 #hw.igb.txd=4096 #hw.igb.rx_process_limit=100 # Some useful netisr tunables. See sysctl net.isr #net.isr.maxthreads=4 #net.isr.defaultqlimit=4096 #net.isr.maxqlimit: 10240 # Bind netisr threads to CPUs #net.isr.bindthreads=1 # # FreeBSD 9.x+ # Increase interface send queue length # See commit message http://svn.freebsd.org/viewvc/base?view=revision&revision=207554 #net.link.ifqmaxlen=1024 # Nicer boot logo =) loader_logo="beastie" And finally here is KERNCONF: # Just some of them, see also # cat /sys/{i386,amd64,}/conf/NOTES # This one useful only on i386 #options KVA_PAGES=512 # You can play with HZ in environments with high interrupt rate (default is 1000) # 100 is for my notebook to prolong it's battery life #options HZ=100 # Polling is goot on network loads with high packet rates and low-end NICs # NB! Do not enable it if you want more than one netisr thread #options DEVICE_POLLING # Eliminate datacopy on socket read-write # To take advantage with zero copy sockets you should have an MTU >= 4k # This req. is only for receiving data. # Read more in man zero_copy_sockets # Also this epic thread on kernel trap: # http://kerneltrap.org/node/6506 # Here Linus says that "anybody that does it that way (FreeBSD) is totally incompetent" #options ZERO_COPY_SOCKETS # Support TCP sign. Used for IPSec options TCP_SIGNATURE # There was stackoverflow found in KAME IPSec stack: # See http://secunia.com/advisories/43995/ # For quick workaround you can use `ipfw add deny proto ipcomp` options IPSEC # This ones can be loaded as modules. They described in loader.conf section #options ACCEPT_FILTER_DATA #options ACCEPT_FILTER_HTTP # Adding ipfw, also can be loaded as modules options IPFIREWALL # On 8.1+ you can disable verbose to see blocked packets on ipfw0 interface. # Also there is no point in compiling verbose into the kernel, because # now there is net.inet.ip.fw.verbose tunable. #options IPFIREWALL_VERBOSE #options IPFIREWALL_VERBOSE_LIMIT=10 options IPFIREWALL_FORWARD # Adding kernel NAT options IPFIREWALL_NAT options LIBALIAS # Traffic shaping options DUMMYNET # Divert, i.e. for userspace NAT options IPDIVERT # This is for OpenBSD's pf firewall device pf device pflog # pf's QoS - ALTQ options ALTQ options ALTQ_CBQ # Class Bases Queuing (CBQ) options ALTQ_RED # Random Early Detection (RED) options ALTQ_RIO # RED In/Out options ALTQ_HFSC # Hierarchical Packet Scheduler (HFSC) options ALTQ_PRIQ # Priority Queuing (PRIQ) options ALTQ_NOPCC # Required for SMP build # Pretty console # Manual can be found here http://forums.freebsd.org/showthread.php?t=6134 #options VESA #options SC_PIXEL_MODE # Disable reboot on Ctrl Alt Del #options SC_DISABLE_REBOOT # Change normal|kernel messages color options SC_NORM_ATTR=(FG_GREEN|BG_BLACK) options SC_KERNEL_CONS_ATTR=(FG_YELLOW|BG_BLACK) # More scroll space options SC_HISTORY_SIZE=8192 # Adding hardware crypto device device crypto device cryptodev # Useful network interfaces device vlan device tap #Virtual Ethernet driver device gre #IP over IP tunneling device if_bridge #Bridge interface device pfsync #synchronization interface for PF device carp #Common Address Redundancy Protocol device enc #IPsec interface device lagg #Link aggregation interface device stf #IPv4-IPv6 port # Also for my notebook, but may be used with Opteron device amdtemp # Same for Intel processors device coretemp # man 4 cpuctl device cpuctl # CPU control pseudo-device # Support for ECMP. More than one route for destination # Works even with default route so one can use it as LB for two ISP # For now code is unstable and panics (panic: rtfree 2) on route deletions. #options RADIX_MPATH # Multicast routing #options MROUTING #options PIM # Debug & DTrace options KDB # Kernel debugger related code options KDB_TRACE # Print a stack trace for a panic options KDTRACE_FRAME # amd64-only(?) options KDTRACE_HOOKS # all architectures - enable general DTrace hooks #options DDB #options DDB_CTF # all architectures - kernel ELF linker loads CTF data # Adaptive spining in lockmgr (8.x+) # See http://www.mail-archive.com/[email protected]/msg10782.html options ADAPTIVE_LOCKMGRS # UTF-8 in console (8.x+) #options TEKEN_UTF8 # FreeBSD 8.1+ # Deadlock resolver thread # For additional information see http://www.mail-archive.com/[email protected]/msg18124.html # (FYI: "resolution" is panic so use with caution) #options DEADLKRES # Increase maximum size of Raw I/O and sendfile(2) readahead #options MAXPHYS=(1024*1024) #options MAXBSIZE=(1024*1024) # For scheduler debug enable following option. # Debug will be available via `kern.sched.stats` sysctl # For more information see http://svnweb.freebsd.org/base/head/sys/conf/NOTES?view=markup #options SCHED_STATS If you are tuning network for maximum performance you may wish to play with ifconfig options like: # You can list all capabilities via `ifconfig -m` ifconfig [-]rxcsum [-]txcsum [-]tso [-]lro mtu In case you've enabled DDB in kernel config, you should edit your /etc/ddb.conf and add something like this to enable automatic reboot (and textdump as bonus): script kdb.enter.panic=textdump set; capture on; show pcpu; bt; ps; alltrace; capture off; call doadump; reset script kdb.enter.default=textdump set; capture on; bt; ps; capture off; call doadump; reset And do not forget to add ddb_enable="YES" to /etc/rc.conf Since FreeBSD 9 you can select to enable/disable flowcontrol on your NIC: # See http://en.wikipedia.org/wiki/Ethernet_flow_control and # http://www.mail-archive.com/[email protected]/msg07927.html for additional info ifconfig bge0 media auto mediaopt flowcontrol PS. Also most of FreeBSD's limits can be monitored by # vmstat -z and # limits PPS. variety of network counters can be monitored via # netstat -s In FreeBSD-9 netstat's -Q option appeared, try following command to display netisr stats # netstat -Q PPPS. also see # man 7 tuning PPPPS. I wanted to thank FreeBSD community, especially author of nginx - Igor Sysoev, nginx-ru@ and FreeBSD-performance@ mailing lists for providing useful information about FreeBSD tuning. FreeBSD WIP * Whats cooking for FreeBSD 7? * Whats cooking for FreeBSD 8? * Whats cooking for FreeBSD 9? So here is the question: What tunings are you using on yours FreeBSD servers? You can also post your /etc/sysctl.conf, /boot/loader.conf, kernel options, etc with description of its' meaning (do not copy-paste from sysctl -d). Don't forget to specify server type (web, smb, gateway, etc) Let's share experience!

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• apache fails to connect to tomcat (Worker config?)

  - by techventure

  I have a tomcat 6 with follwoing server.xml: <Connector port="8253" maxThreads="150" minSpareThreads="25" maxSpareThreads="75" enableLookups="false" redirectPort="8445" acceptCount="100" debug="0" connectionTimeout="20000" disableUploadTimeout="true" /> <Connector port="8014" protocol="AJP/1.3" redirectPort="8445" /> and in added worker.properties: # Set properties for worker4 (ajp13) worker.worker4.type=ajp13 worker.worker4.host=localhost worker.worker4.port=8014 and i put in httpd.conf: JkMount /myWebApp/* worker4 It is not working a as trying to navigate to www1.myCompany.com/myWebApp gives "Service Temporarily Unavailable". I checked in tomcat catalina.out and it says: INFO: JK: ajp13 listening on /0.0.0.0:8014 UPDATE: i put mod_jk log level to debug and below is the result: [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_set_time_fmt::jk_util.c (458): Pre-processed log time stamp format is '[%a %b %d %H:%M:%S %Y] ' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_open::jk_uri_worker_map.c (770): rule map size is 8 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_add::jk_uri_worker_map.c (720): wildchar rule '/myWebApp/*=worker4' source 'JkMount' was added [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (171): uri map dump after map open: index=0 file='(null)' reject_unsafe=0 reload=60 modified=0 checked=0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 0: size=0 nosize=0 capacity=0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 1: size=8 nosize=0 capacity=8 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (186): NEXT (1) map #3: uri=/myWebApp/* worker=worker4 context=/myWebApp/* source=JkMount type=Wildchar len=6 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_set_time_fmt::jk_util.c (458): Pre-processed log time stamp format is '[%a %b %d %H:%M:%S %Y] ' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] init_jk::mod_jk.c (3123): Setting default connection pool max size to 1 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.list' with value 'worker1,worker2,worker3,worker4' to map. [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.worker4.type' with value 'ajp13' to map. [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.worker4.host' with value 'localhost' to map. [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.worker4.port' with value '8014' to map. [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_resolve_references::jk_map.c (774): Checking for references with prefix worker. with wildcard (recursion 1) [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_shm_calculate_size::jk_shm.c (132): shared memory will contain 4 ajp workers of size 256 and 0 lb workers of size 320 with 0 members of size 320+256 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [error] init_jk::mod_jk.c (3166): Initializing shm:/var/log/httpd/mod_jk.shm.9552 errno=13. Load balancing workers will not function properly. [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'ServerRoot' -> '/etc/httpd' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.list' -> 'worker1,worker2,worker3,worker4' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker1.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker1.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker1.port' -> '8009' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker2.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker2.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker2.port' -> '8010' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker3.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker3.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker3.port' -> '8112' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker4.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker4.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker4.port' -> '8014' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] build_worker_map::jk_worker.c (242): creating worker worker4 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] wc_create_worker::jk_worker.c (146): about to create instance worker4 of ajp13 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] wc_create_worker::jk_worker.c (159): about to validate and init worker4 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_validate::jk_ajp_common.c (2512): worker worker4 contact is 'localhost:8014' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2699): setting endpoint options: [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2702): keepalive: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2706): socket timeout: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2710): socket connect timeout: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2714): buffer size: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2718): pool timeout: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2722): ping timeout: 10000 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2726): connect timeout: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2730): reply timeout: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2734): prepost timeout: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2738): recovery options: 0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2742): retries: 2 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2746): max packet size: 8192 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_init::jk_ajp_common.c (2750): retry interval: 100 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] ajp_create_endpoint_cache::jk_ajp_common.c (2562): setting connection pool size to 1 with min 1 and acquire timeout 200 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [info] init_jk::mod_jk.c (3183): mod_jk/1.2.28 initialized [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] wc_get_worker_for_name::jk_worker.c (116): found a worker worker4 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] wc_get_name_for_type::jk_worker.c (293): Found worker type 'ajp13' [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_ext::jk_uri_worker_map.c (512): Checking extension for worker 3: worker4 of type ajp13 (2) [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (171): uri map dump after extension stripping: index=0 file='(null)' reject_unsafe=0 reload=60 modified=0 checked=0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 0: size=0 nosize=0 capacity=0 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 1: size=8 nosize=0 capacity=8 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (186): NEXT (1) map #3: uri=/myWebApp/* worker=worker4 context=/myWebApp/* source=JkMount type=Wildchar len=6 [Wed Jun 13 18:44:26 2012] [9552:3086317328] [debug] uri_worker_map_switch::jk_uri_worker_map.c (482): Switching uri worker map from index 0 to index 1 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_set_time_fmt::jk_util.c (458): Pre-processed log time stamp format is '[%a %b %d %H:%M:%S %Y] ' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_open::jk_uri_worker_map.c (770): rule map size is 8 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_add::jk_uri_worker_map.c (720): wildchar rule '/myWebApp/*=worker4' source 'JkMount' was added [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (171): uri map dump after map open: index=0 file='(null)' reject_unsafe=0 reload=60 modified=0 checked=0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 0: size=0 nosize=0 capacity=0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 1: size=8 nosize=0 capacity=8 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (186): NEXT (1) map #0: uri=/jsp-examples/* worker=worker1 context=/jsp-examples/* source=JkMount type=Wildchar len=15 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (186): NEXT (1) map #3: uri=/myWebApp/* worker=worker4 context=/myWebApp/* source=JkMount type=Wildchar len=6 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_set_time_fmt::jk_util.c (458): Pre-processed log time stamp format is '[%a %b %d %H:%M:%S %Y] ' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] init_jk::mod_jk.c (3123): Setting default connection pool max size to 1 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.list' with value 'worker1,worker2,worker3,worker4' to map. [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.worker4.type' with value 'ajp13' to map. [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.worker4.host' with value 'localhost' to map. [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_read_property::jk_map.c (491): Adding property 'worker.worker4.port' with value '8014' to map. [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_resolve_references::jk_map.c (774): Checking for references with prefix worker. with wildcard (recursion 1) [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_shm_calculate_size::jk_shm.c (132): shared memory will contain 4 ajp workers of size 256 and 0 lb workers of size 320 with 0 members of size 320+256 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [error] init_jk::mod_jk.c (3166): Initializing shm:/var/log/httpd/mod_jk.shm.9553 errno=13. Load balancing workers will not function properly. [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'ServerRoot' -> '/etc/httpd' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.list' -> 'worker1,worker2,worker3,worker4' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker1.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker1.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker1.port' -> '8009' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker2.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker2.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker2.port' -> '8010' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker3.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker3.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker3.port' -> '8112' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker4.type' -> 'ajp13' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker4.host' -> 'localhost' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] jk_map_dump::jk_map.c (589): Dump of map: 'worker.worker4.port' -> '8014' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] build_worker_map::jk_worker.c (242): creating worker worker4 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] wc_create_worker::jk_worker.c (146): about to create instance worker4 of ajp13 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] wc_create_worker::jk_worker.c (159): about to validate and init worker4 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_validate::jk_ajp_common.c (2512): worker worker4 contact is 'localhost:8014' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2699): setting endpoint options: [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2702): keepalive: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2706): socket timeout: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2710): socket connect timeout: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2714): buffer size: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2718): pool timeout: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2722): ping timeout: 10000 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2726): connect timeout: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2730): reply timeout: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2734): prepost timeout: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2738): recovery options: 0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2742): retries: 2 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2746): max packet size: 8192 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_init::jk_ajp_common.c (2750): retry interval: 100 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] ajp_create_endpoint_cache::jk_ajp_common.c (2562): setting connection pool size to 1 with min 1 and acquire timeout 200 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [info] init_jk::mod_jk.c (3183): mod_jk/1.2.28 initialized [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] wc_get_worker_for_name::jk_worker.c (116): found a worker worker4 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] wc_get_name_for_type::jk_worker.c (293): Found worker type 'ajp13' [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_ext::jk_uri_worker_map.c (512): Checking extension for worker 3: worker4 of type ajp13 (2) [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (171): uri map dump after extension stripping: index=0 file='(null)' reject_unsafe=0 reload=60 modified=0 checked=0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 0: size=0 nosize=0 capacity=0 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (176): generation 1: size=8 nosize=0 capacity=8 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_dump::jk_uri_worker_map.c (186): NEXT (1) map #3: uri=/myWebApp/* worker=worker4 context=/myWebApp/* source=JkMount type=Wildchar len=6 [Wed Jun 13 18:44:26 2012] [9553:3086317328] [debug] uri_worker_map_switch::jk_uri_worker_map.c (482): Switching uri worker map from index 0 to index 1 [Wed Jun 13 18:44:26 2012] [9555:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9556:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9557:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9558:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9559:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9560:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9561:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9562:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9563:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9564:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9565:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9567:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9568:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9566:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9569:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:26 2012] [9570:3086317328] [debug] jk_child_init::mod_jk.c (3068): Initialized mod_jk/1.2.28 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] map_uri_to_worker_ext::jk_uri_worker_map.c (1036): Attempting to map URI '/myWebApp/jsp/login.faces' from 8 maps [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/myWebApp/*=worker4' source 'JkMount' [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] find_match::jk_uri_worker_map.c (863): Found a wildchar match '/myWebApp/*=worker4' [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] jk_handler::mod_jk.c (2459): Into handler jakarta-servlet worker=worker4 r->proxyreq=0 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] wc_get_worker_for_name::jk_worker.c (116): found a worker worker4 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] wc_maintain::jk_worker.c (339): Maintaining worker worker1 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] wc_maintain::jk_worker.c (339): Maintaining worker worker2 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] wc_maintain::jk_worker.c (339): Maintaining worker worker3 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] wc_maintain::jk_worker.c (339): Maintaining worker worker4 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] wc_get_name_for_type::jk_worker.c (293): Found worker type 'ajp13' [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] init_ws_service::mod_jk.c (977): Service protocol=HTTP/1.1 method=GET ssl=false host=(null) addr=167.184.214.6 name=www1.myCompany.com.au port=80 auth=(null) user=(null) laddr=10.215.222.78 raddr=167.184.214.6 uri=/myWebApp/jsp/login.faces [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_get_endpoint::jk_ajp_common.c (2977): acquired connection pool slot=0 after 0 retries [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_marshal_into_msgb::jk_ajp_common.c (605): ajp marshaling done [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_service::jk_ajp_common.c (2283): processing worker4 with 2 retries [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_send_request::jk_ajp_common.c (1501): (worker4) all endpoints are disconnected. [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] jk_open_socket::jk_connect.c (452): socket TCP_NODELAY set to On [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] jk_open_socket::jk_connect.c (576): trying to connect socket 18 to 127.0.0.1:8014 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] jk_open_socket::jk_connect.c (594): connect to 127.0.0.1:8014 failed (errno=13) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] ajp_connect_to_endpoint::jk_ajp_common.c (922): Failed opening socket to (127.0.0.1:8014) (errno=13) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [error] ajp_send_request::jk_ajp_common.c (1507): (worker4) connecting to backend failed. Tomcat is probably not started or is listening on the wrong port (errno=13) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] ajp_service::jk_ajp_common.c (2447): (worker4) sending request to tomcat failed (recoverable), because of error during request sending (attempt=1) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_service::jk_ajp_common.c (2304): retry 1, sleeping for 100 ms before retrying [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_send_request::jk_ajp_common.c (1501): (worker4) all endpoints are disconnected. [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] jk_open_socket::jk_connect.c (452): socket TCP_NODELAY set to On [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] jk_open_socket::jk_connect.c (576): trying to connect socket 18 to 127.0.0.1:8014 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] jk_open_socket::jk_connect.c (594): connect to 127.0.0.1:8014 failed (errno=13) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] ajp_connect_to_endpoint::jk_ajp_common.c (922): Failed opening socket to (127.0.0.1:8014) (errno=13) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [error] ajp_send_request::jk_ajp_common.c (1507): (worker4) connecting to backend failed. Tomcat is probably not started or is listening on the wrong port (errno=13) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] ajp_service::jk_ajp_common.c (2447): (worker4) sending request to tomcat failed (recoverable), because of error during request sending (attempt=2) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [error] ajp_service::jk_ajp_common.c (2466): (worker4) connecting to tomcat failed. [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_reset_endpoint::jk_ajp_common.c (743): (worker4) resetting endpoint with sd = 4294967295 (socket shutdown) [Wed Jun 13 18:44:54 2012] [9555:3086317328] [debug] ajp_done::jk_ajp_common.c (2905): recycling connection pool slot=0 for worker worker4 [Wed Jun 13 18:44:54 2012] [9555:3086317328] [info] jk_handler::mod_jk.c (2615): Service error=-3 for worker=worker4 The error i get in browser is: Service Temporarily Unavailable Apache/2.2.3 (Red Hat) Server at www1.myCompany.com.au Port 80 can someone please help and explain what is going on and how it can be resolved?

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• SharpDX: best practice for multiple RenderForms?

  - by Rob Jellinghaus

  I have an XNA app, but I really need to add multiple render windows, which XNA doesn't do. I'm looking at SharpDX (both for multi-window support and for DX11 / Metro / many other reasons). I decided to hack up the SharpDX DX11 MultiCubeTexture sample to see if I could make it work. My changes are pretty trivial. The original sample had: [STAThread] private static void Main() { var form = new RenderForm("SharpDX - MiniCubeTexture Direct3D11 Sample"); ... I changed this to: struct RenderFormWithActions { internal readonly RenderForm Form; // should just be Action but it's not in System namespace?! internal readonly Action RenderAction; internal readonly Action DisposeAction; internal RenderFormWithActions(RenderForm form, Action renderAction, Action disposeAction) { Form = form; RenderAction = renderAction; DisposeAction = disposeAction; } } [STAThread] private static void Main() { // hackity hack new Thread(new ThreadStart(() = { RenderFormWithActions form1 = CreateRenderForm(); RenderLoop.Run(form1.Form, () = form1.RenderAction(0)); form1.DisposeAction(0); })).Start(); new Thread(new ThreadStart(() = { RenderFormWithActions form2 = CreateRenderForm(); RenderLoop.Run(form2.Form, () = form2.RenderAction(0)); form2.DisposeAction(0); })).Start(); } private static RenderFormWithActions CreateRenderForm() { var form = new RenderForm("SharpDX - MiniCubeTexture Direct3D11 Sample"); ... Basically, I split out all the Main() code into a separate method which creates a RenderForm and two delegates (a render delegate, and a dispose delegate), and bundles them all together into a struct. I call this method twice, each time from a separate, new thread. Then I just have one RenderLoop on each new thread. I was thinking this wouldn't work because of the [STAThread] declaration -- I thought I would need to create the RenderForm on the main (STA) thread, and run only a single RenderLoop on that thread. Fortunately, it seems I was wrong. This works quite well -- if you drag one of the forms around, it stops rendering while being dragged, but starts again when you drop it; and the other form keeps chugging away. My questions are pretty basic: Is this a reasonable approach, or is there some lurking threading issue that might make trouble? My code simply duplicates all the setup code -- it makes a duplicate SwapChain, Device, Texture2D, vertex buffer, everything. I don't have a problem with this level of duplication -- my app is not intensive enough to suffer resource issues -- but nonetheless, is there a better practice? Is there any good reference for which DirectX structures can safely be shared, and which can't? It appears that RenderLoop.Run calls the render delegate in a tight loop. Is there any standard way to limit the frame rate of RenderLoop.Run, if you don't want a 400FPS app eating 100% of your CPU? Should I just Thread.Sleep(30) in the render delegate? (I asked on the sharpdx.org forums as well, but Alexandre is on vacation for two weeks, and my sister wants me to do a performance with my app at her wedding in three and a half weeks, so I'm mighty incented here! http://robjsoftware.org for details of what I'm building....)

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• Visual Studio 2010 Productivity Power Tool Extensions

  - by ScottGu

  Last month I blogged about the Extension Manager that is built-into VS 2010 – as well as about a cool VS 2010 PowerCommands extension that provides some extra features for Visual Studio.  The Visual Studio 2010 Extension Manager provides an easy way for developers to quickly find and install extensions and plugins that enhance the built-in functionality to VS 2010. New VS 2010 Productivity Power Tools Release Earlier this week Jason Zander announced the availability of a new VS 2010 Productivity Power Tools release that includes a bunch of great new VS 2010 extensions that provide a bunch of cool new functionality for you to take advantage of.  You can download and install the release for free here.  Some of the code editor improvements it provides include: Entire Line Highlighting: Makes it easier to track cursor location within the editor Entire Line Selection: Triple Clicking a line in the code editor now selects the entire line (like with MS Word) Code Block Movement: Use Alt+Up/Down Arrow now moves selected code blocks up/down in the editor Consistent Tabs vs. Spaces: Ensure consistent tab vs. space usage across your projects Colorized Parameters: It is now easier to see/identify method parameters Column Guide: You can now add vertical column guidelines to help with text alignment and sizes Align assignments: Makes it easier to line-up multiple variable assignments within your code HTML Clipboard Support: Copy/paste code from VS into an HTML buffer (useful for blogging!) Ctrl + Click Go to Definition: You can now hold down the Ctrl key and click a type to go to its definition It also includes several tab management improvements for managing document tabs within the IDE: Show Close Button in Tab Well: Shows a close button in document well for the active tab (like VS 2008 did) Colored Tabs: You can now select the color of each document tab by project or by regex Pinned Tabs: Enables you to pin tabs to keep them always visible and available Vertical Tabs: You can now show document tabs vertically to fit more tabs than normal Remove Tabs by Usage Order: Better behavior when adding new tabs and one needs to be hidden for space reasons Sort Tabs by Project: Tabs can be sorted by project they belong to, keeping them grouped together Sort Tabs Alphabetically: Tabs can be sorted alphabetically And last – but not least – it includes a new and improved “Add Reference” dialog: This new Add Reference dialog caches assembly information – which means it loads within a second or two (note: the very first time it still loads assembly data – but it then caches it and makes it fast afterwards). The new Add Reference dialog also now includes searching support – making it easier to find the assembly you are looking for. You can read more about all of the above improvements in Jason’s blog post about the release. New Visualization and Modeling Feature Pack Release Earlier this week we also shipped a new feature pack that adds additional modeling and code visualization features to VS 2010 Ultimate.  You can download it here. The Visualization and Modeling Feature Pack includes a bunch of great new capabilities including: Web Site Visualization: New support for generating a DGML visualization for ASP.NET projects C/C++ Native Code Visualization: New support for generating DGML diagrams for C/C++ projects Generate Code from UML Class Diagrams: You can now generate code from your UML diagrams Create UML Class Diagrams from Code: Create UML diagrams from existing code bases Import UML from XML: Import UML class, sequence, and use case elements from XMI 2.1 files Custom Validation Layer Rules: Write custom code to create, modify, and validate layer diagrams Jason’s blog post covers more about these features as well. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• MSMQ messages using HTTP just won't get delivered

  - by John Breakwell

  I'm starting off the blog with a discussion of an unusual problem that has hit a couple of my customers this month. It's not a problem you'd expect to bump into and the solution is potentially painful. Scenario You want to make use of the HTTP protocol to send MSMQ messages from one machine to another. You have installed HTTP support for MSMQ and have addressed your messages correctly but they will not leave the outgoing queue. There is no configuration for HTTP support - setup has already done all that for you (although you may want to check the most recent "Installation of the MSMQ HTTP Support Subcomponent" section of MSMQINST.LOG to see if anything DID go wrong) - so you can't tweak anything. Restarting services and servers makes no difference - the messages just will not get delivered. The problem is documented and resolved by Knowledgebase article 916699 "The message may not be delivered when you use the HTTP protocol to send a message to a server that is running Message Queuing 3.0". It is unlikely that you would be able to resolve the problem without the assistance of PSS because there are no messages that can be seen to assist you and only access to the source code exposes the root cause. As this communication is over HTTP, the IIS logs would be a good place to start. POST entries are logged which show that connectivity is working and message delivery is being attempted: #Software: Microsoft Internet Information Services 6.0 #Version: 1.0 #Date: 2006-09-12 12:11:29 #Fields: date time s-sitename s-ip cs-method cs-uri-stem cs-uri-query s-port cs-username c-ip cs(User-Agent) sc-status sc-substatus sc-win32-status 2006-09-12 12:12:12 W3SVC1 10.1.17.219 POST /msmq/private$/test - 80 - 10.2.200.3 - 200 0 0 If you capture the traffic with Network Monitor you can see the POST being sent to the server but you also see a response being returned to the client: HTTP: Response to Client; HTTP/1.1; Status Code = 500 - Internal Server Error "Internal Server Error" means we can probably stop looking at IIS and instead focus on the Message Queuing ISAPI extension (Mqise.dll). MSMQ 3.0 (Windows XP and Windows Server 2003) comes with error logging enabled by default but the log files are in binary format - MSMQ 2.0 generated logging in plain text. The symbolic information needed for formatting the files is not currently publicly available so log files have to be sent in to Microsoft PSS.  Although this does mean raising a support case, formatting the log files to text and returning them to the customer shouldn't take long. Obviously the engineer analyses them for you - I just want to point out that you can see the logging output in text format if you want it. The important entries in the log for this problem are: [7]b48.928 09/12/2006-13:20:44.552 [mqise GetNetBiosNameFromIPAddr] ERROR:Failed to get the NetBios name from the DNS name, error = 0xea [7]b48.928 09/12/2006-13:20:44.552 [mqise RPCToServer] ERROR:RPC call R_ProcessHTTPRequest failed, error code = 1702(RPC_S_INVALID_BINDING) which allow a Microsoft escalation engineer to check the MQISE source code to see what is going wrong. This problem according to the article occurs when the extension tries to bind to the local MSMQ service after the extension receives a POST request that contains an MSMQ message. MSMQ resolves the server name by using the DNS host name but the extension cannot bind to the service because the buffer that MSMQ uses to resolve the server name is too small - server names that are exactly 15 characters long will not fit. RPC exception 0x6a6 (RPC_S_INVALID_BINDING) occurs in the W3wp.exe process but the exception is handled and so you do not receive an error message. The workaround is to rename the MSMQ server to something less than 15 characters. If the problem has only just been noticed in a production environment - an application may have been modified to get through a newly-implemented firewall, for example - then renaming is going to be an issue. Other applications may need to be reinstalled or modified if server names are hard-coded or stored in the registry. The renaming may also break a company naming convention where the name is built up from something like location+department+number. If you want to learn more about MSMQ logging then check out Chapter 15 of the MSMQ FAQ. In fact, even if you DON'T want to learn anything about MSMQ logging you should read the FAQ anyway as there is a huge amount of useful information on known issues and the like.

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• Asynchrony in C# 5: Dataflow Async Logger Sample

  - by javarg

  Check out this (very simple) code examples for TPL Dataflow. Suppose you are developing an Async Logger to register application events to different sinks or log writers. The logger architecture would be as follow: Note how blocks can be composed to achieved desired behavior. The BufferBlock<T> is the pool of log entries to be process whereas linked ActionBlock<TInput> represent the log writers or sinks. The previous composition would allows only one ActionBlock to consume entries at a time. Implementation code would be something similar to (add reference to System.Threading.Tasks.Dataflow.dll in %User Documents%\Microsoft Visual Studio Async CTP\Documentation): TPL Dataflow Logger var bufferBlock = new BufferBlock<Tuple<LogLevel, string>>(); ActionBlock<Tuple<LogLevel, string>> infoLogger =     new ActionBlock<Tuple<LogLevel, string>>(         e => Console.WriteLine("Info: {0}", e.Item2)); ActionBlock<Tuple<LogLevel, string>> errorLogger =     new ActionBlock<Tuple<LogLevel, string>>(         e => Console.WriteLine("Error: {0}", e.Item2)); bufferBlock.LinkTo(infoLogger, e => (e.Item1 & LogLevel.Info) != LogLevel.None); bufferBlock.LinkTo(errorLogger, e => (e.Item1 & LogLevel.Error) != LogLevel.None); bufferBlock.Post(new Tuple<LogLevel, string>(LogLevel.Info, "info message")); bufferBlock.Post(new Tuple<LogLevel, string>(LogLevel.Error, "error message")); Note the filter applied to each link (in this case, the Logging Level selects the writer used). We can specify message filters using Predicate functions on each link. Now, the previous sample is useless for a Logger since Logging Level is not exclusive (thus, several writers could be used to process a single message). Let´s use a Broadcast<T> buffer instead of a BufferBlock<T>. Broadcast Logger var bufferBlock = new BroadcastBlock<Tuple<LogLevel, string>>(     e => new Tuple<LogLevel, string>(e.Item1, e.Item2)); ActionBlock<Tuple<LogLevel, string>> infoLogger =     new ActionBlock<Tuple<LogLevel, string>>(         e => Console.WriteLine("Info: {0}", e.Item2)); ActionBlock<Tuple<LogLevel, string>> errorLogger =     new ActionBlock<Tuple<LogLevel, string>>(         e => Console.WriteLine("Error: {0}", e.Item2)); ActionBlock<Tuple<LogLevel, string>> allLogger =     new ActionBlock<Tuple<LogLevel, string>>(     e => Console.WriteLine("All: {0}", e.Item2)); bufferBlock.LinkTo(infoLogger, e => (e.Item1 & LogLevel.Info) != LogLevel.None); bufferBlock.LinkTo(errorLogger, e => (e.Item1 & LogLevel.Error) != LogLevel.None); bufferBlock.LinkTo(allLogger, e => (e.Item1 & LogLevel.All) != LogLevel.None); bufferBlock.Post(new Tuple<LogLevel, string>(LogLevel.Info, "info message")); bufferBlock.Post(new Tuple<LogLevel, string>(LogLevel.Error, "error message")); As this block copies the message to all its outputs, we need to define the copy function in the block constructor. In this case we create a new Tuple, but you can always use the Identity function if passing the same reference to every output. Try both scenarios and compare the results.

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• OOW 2013 Summary for Fusion Middleware Architects & Administrators by Simon Haslam

  - by JuergenKress

  OOW 2013 Summary for Fusion Middleware Architects & Administrators by Simon Haslam This September during Oracle OpenWorld 2013 the weather in San Francisco, as you see can from the photo, was exceptionally sunny. The dramatic final few days of the Americas Cup sailing competition, being held every day in the bay, coincided with the conference and meant that there was almost a holiday feel to the whole event. Here's my annual round-up of what I think was most interesting at OpenWorld 2013 for Fusion Middleware architects and administrators; I hope you find it useful and if you think I've missed something please add a comment! WebLogic and Cloud Application Foundation (CAF) The big WebLogic release of the year has already happened a few months ago with 12.1.2 so I won't duplicate that here. Will Lyons discussed the WebLogic and Coherence roadmap which essentially is that 12.1.3 will probably be released to coincide with SOA 12c next year and that 12.1.4, the next feature-rich WebLogic release, is more likely to be in 2015. This latter release will probably include full Java EE 7 support, have enhancements for multi-tenancy and further auto-scaling features to support increased density (i.e. more WebLogic usage for the same amount of hardware). There's a new Oracle Virtual Assembly Builder (OVAB) out already and an Oracle Traffic Director (OTD) 12c release round the corner too. Also of relevance to administrators is that Oracle has increased the support lifetime for Fusion Middleware 11g (e.g. WebLogic 10.3.6) so that Premier Support will now run to the end of 2018 and Extended Support until 2021 - this should remove any Oracle-driven pressure to upgrade at least. Java Mission Control Java Mission Control (JMC) is the HotSpot Java 7 version of JRockit 6 Mission Control, a very nice performance monitoring tool from Oracle's BEA acquisition. Flight Recorder is a feature built into the JVM which records diagnostic events into, typically, a circular buffer which can then be used for historical analysis, particularly in the case of a JVM crash or hang. It's been available separately for WebLogic only for perhaps a year now but, more significantly, it now includes JVM events and was bundled in with JDK7 Update 40 a few weeks ago. I attended a couple of interesting Java One sessions on JMC/Flight Recorder and have to say it's looking really good - it has all the previous JRMC features except for memory leak detector, plus some enhancements around operative sets and ECID filtering I think. Marcus also showed how you could add your own events into flight recorder by building your own event class - they are then available for graphing alongside all the other events in JMC. This uses a currently an unsupported/undocumented API, but it's also the same one that WebLogic uses for WLDF events so I imagine it is stable. I'm not sure quite whether this would be useful to custom applications, as opposed to infrastructure services or ISV packaged applications, but it was a very nice demonstration. I've been testing JMC / FR enabling on several environments recently and my confidence is growing - it feels robust and I think could very soon be part of my standard builds. Read the full article here. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: OOW,Simon Haslam,Oracle OpenWorld,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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• July, the 31 Days of SQL Server DMO’s – Day 19 (sys.dm_exec_query_stats)

  - by Tamarick Hill

  The sys.dm_exec_query_stats DMV is one of the most useful DMV’s out there when it comes to performance tuning. If you have been keeping up with this blog series this month, you know that I started out on Day 1 reviewing many of the DMV’s within the ‘exec’ namespace. I’m not sure how I missed this one considering how valuable it is, but hey, they say it’s better late than never right?? On Day 7 and Day 8 we reviewed the sys.dm_exec_procedure_stats and sys.dm_exec_trigger_stats respectively. This sys.dm_exec_query_stats DMV is very similar to these two. As a matter of fact, this DMV will return all of the information you saw in the other two DMV’s, but in addition to that, you can see stats for all queries that have cached execution plans on your server. You can even see stats for statements that are ran Ad-Hoc as long as they are still cached in the buffer pool. To better illustrate this DMV, let have a quick look at it: SELECT * FROM sys.dm_exec_query_stats As you can see, there is a lot of information returned from this DMV. I wont go into detail about each and every one of these columns, but I will touch on a few of them briefly. The first column is the ‘sql_handle’, which if you remember from Day 4 of our blog series, I explained how you can use this column to extract the actual SQL text that was executed. The next columns statement_start_offset and statement_end_offset provide you a way of extracting the exact SQL statement that was executed as part of a batch. The plan_handle column is used to extract the Execution plan that was used, which we talked about during Day 5 of this blog series. Later in the result set, you have columns to identify how many times a particular statement was executed, how much CPU time it used, how many reads/writes it performed, the duration, how many rows were returned, etc. These columns provide you with a solid avenue to begin your performance optimization. The last column I will touch on is the query_plan_hash column. A lot of times when you have Dynamic SQL running on your server, you have similar statements with different parameter values being passed in. Many times these types of statements will get similar execution plans and then a Binary hash value can be generated based on these similar plans. This query plan hash can be used to find the cost of all queries that have similar execution plans and then you can tune based on that plan to improve the performance of all of the individual queries. This is a very powerful way of identifying and tuning Ad-hoc statements that run on your server. As I stated earlier, this sys.dm_exec_query_stats DMV is a very powerful and recommended DMV for performance tuning. You are able to quickly identify statements that are running on your server and analyze their impact on system resources. Using this DMV to track down the biggest performance killers on your server will allow you to make the biggest gains once you focus your tuning efforts on those top offenders. For more information about this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms189741.aspx Follow me on Twitter @PrimeTimeDBA

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• Improving performance of a particle system (OpenGL ES)

  - by Jason

  I'm in the process of implementing a simple particle system for a 2D mobile game (using OpenGL ES 2.0). It's working, but it's pretty slow. I start getting frame rate battering after about 400 particles, which I think is pretty low. Here's a summary of my approach: I start with point sprites (GL_POINTS) rendered in a batch just using a native float buffer (I'm in Java-land on Android, so that translates as a java.nio.FloatBuffer). On GL context init, the following are set: GLES20.glViewport(0, 0, width, height); GLES20.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); GLES20.glEnable(GLES20.GL_CULL_FACE); GLES20.glDisable(GLES20.GL_DEPTH_TEST); Each draw frame sets the following: GLES20.glEnable(GLES20.GL_BLEND); GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA); And I bind a single texture: GLES20.glActiveTexture(GLES20.GL_TEXTURE0); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle); GLES20.glUniform1i(mUniformTextureHandle, 0); Which is just a simple circle with some blur (and hence some transparency) http://cl.ly/image/0K2V2p2L1H2x Then there are a bunch of glVertexAttribPointer calls: mBuffer.position(position); mGlEs20.glVertexAttribPointer(mAttributeRGBHandle, valsPerRGB, GLES20.GL_FLOAT, false, stride, mBuffer); ...4 more of these Then I'm drawing: GLES20.glUniformMatrix4fv(mUniformProjectionMatrixHandle, 1, false, Camera.mProjectionMatrix, 0); GLES20.glDrawArrays(GLES20.GL_POINTS, 0, drawCalls); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0); My vertex shader does have some computation in it, but given that they're point sprites (with only 2 coordinate values) I'm not sure this is the problem: #ifdef GL_ES // Set the default precision to low. precision lowp float; #endif uniform mat4 u_ProjectionMatrix; attribute vec4 a_Position; attribute float a_PointSize; attribute vec3 a_RGB; attribute float a_Alpha; attribute float a_Burn; varying vec4 v_Color; void main() { vec3 v_FGC = a_RGB * a_Alpha; v_Color = vec4(v_FGC.x, v_FGC.y, v_FGC.z, a_Alpha * (1.0 - a_Burn)); gl_PointSize = a_PointSize; gl_Position = u_ProjectionMatrix * a_Position; } My fragment shader couldn't really be simpler: #ifdef GL_ES // Set the default precision to low. precision lowp float; #endif uniform sampler2D u_Texture; varying vec4 v_Color; void main() { gl_FragColor = texture2D(u_Texture, gl_PointCoord) * v_Color; } That's about it. I had read that transparent pixels in point sprites can cause issues, but surely not at only 400 points? I'm running on a fairly new device (12 month old Galaxy Nexus). My question is less about my approach (although I'm open to suggestion) but more about whether there are any specific OpenGL "no no's" that have leaked into my code. I'm sure there's GL master out there facepalming right now... I'd love to hear any critique.

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• how to drawing continues line just like in paint [on hold]

  - by hussain shah

  hi sir i want to draw a points.the following code is work good but the problem is than when i drag the mouse button, if i move slow working good but if i move the curser fast they cannot made continues line.please what is the solution...? #include <iostream> #include <GL/glut.h> #include <GL/glu.h> #include <stdlib.h> void first() { glPushMatrix(); glTranslatef(1,01,01); glScalef(1, 1, 1); glColor3f(0, 1, 0); glBegin(GL_QUADS); glVertex2f(0.8, 0.6); glVertex2f(0.6, 0.6); glVertex2f(0.6, 0.8); glVertex2f(0.8, 0.8); glEnd(); glPopMatrix(); glFlush(); } void display (void) { glClear(GL_COLOR_BUFFER_BIT); //store color of each pixels of a frame glClearColor(0, 0, 0, 0);// screen color //glFlush(); } void drag (int x, int y) { { y=500-y; //x=500-x; glPointSize(5); glColor3f(1.0,1.0,1.0); glBegin(GL_POINTS); glVertex2f(x,y+2); glEnd(); glutSwapBuffers(); glFlush(); } } void reshape (int w, int h){} void init (void) { glClear(GL_COLOR_BUFFER_BIT); //store color of each pixels of a frame glClearColor(0, 0, 0, 0); glViewport(0,0,500,500); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0.0, 500.0, 0.0, 500.0, 1.0, -1.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void mouse_button (int button, int state, int x, int y) { if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) { drag(x,y); first(); } //else if (button == GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) //{ // //} else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN) { exit(0); } } int main (int argc, char**argv) { glutInit (&argc, argv); //initialize the program. glutInitDisplayMode (GLUT_SINGLE); //set up a basic display buffer (only singular for now) glutInitWindowSize (500,500); //set whe width and height of the window glutInitWindowPosition (100, 100); //set the position of the window glutCreateWindow ("A basic OpenGL Window"); //set the caption for the window glutMotionFunc(drag); //glutMouseFunc(mouse_button); init(); glutDisplayFunc (display);//call the display function to draw our world glutMainLoop(); //initialize the OpenGL loop cycle return 0; }

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