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• Mounted HDD not having enough permissions from Apache/PHP

  - by Dan

  Piwigo gallery, on apache and php, CentOS 6. The root system is a RAID 128GB. /var/www/html is on the root file system. Mounted the 320GB hdd to /var/www/html/320 using defaults, it's an ext4 fs. Put a symlink to it in /var/www/html/galleries which is read by the gallery script so I can upload images to there, then click sync. It gives me the error: [./galleries/] PWG-ERROR-NO-FS (File/directory read error) PWG-ERROR-NO-FS: The file or directory cannot be accessed (either it does not exist or the access is denied) chmod 777 set on /dev/sdb1, /var/www/html, and /var/www/html/320 as well as the symlink galleries too. All recursive. chown apache:apache to everything too. PHP just can't read/write to it. I tried with and without the symlink, I've tried everything I can think of. Nothing. Any ideas how I can give apache/php permission to read/write to this drive? With 777 permissions all around it should already be able to.

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• How to test nginx proxy timeouts

  - by mkorszun

  Target: I would like to test all Nginx proxy timeout parameters in very simple scenario. My first approach was to create really simple HTTP server and put some timeouts: Between listen and accept to test proxy_connect_timeout Between accept and read to test proxy_send_timeout Between read and send to test proxy_read_timeout Test: 1) Server code (python): import socket import os import time import threading def http_resp(conn): conn.send("HTTP/1.1 200 OK\r\n") conn.send("Content-Length: 0\r\n") conn.send("Content-Type: text/xml\r\n\r\n\r\n") def do(conn, addr): print 'Connected by', addr print 'Sleeping before reading data...' time.sleep(0) # Set to test proxy_send_timeout data = conn.recv(1024) print 'Sleeping before sending data...' time.sleep(0) # Set to test proxy_read_timeout http_resp(conn) print 'End of data stream, closing connection' conn.close() def main(): s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) s.bind(('', int(os.environ['PORT']))) s.listen(1) print 'Sleeping before accept...' time.sleep(130) # Set to test proxy_connect_timeout while 1: conn, addr = s.accept() t = threading.Thread(target=do, args=(conn, addr)) t.start() if __name__ == "__main__": main() 2) Nginx configuration: I have extended Nginx default configuration by setting explicitly proxy_connect_timeout and adding proxy_pass pointing to my local HTTP server: location / { proxy_pass http://localhost:8888; proxy_connect_timeout 200; } 3) Observation: proxy_connect_timeout - Even though setting it to 200s and sleeping only 130s between listen and accept Nginx returns 504 after ~60s which might be because of the default proxy_read_timeout value. I do not understand how proxy_read_timeout could affect connection at so early stage (before accept). I would expect 200 here. Please explain! proxy_send_timeout - I am not sure if my approach to test proxy_send_timeout is correct - i think i still do not understand this parameter correctly. After all, delay between accept and read does not force proxy_send_timeout. proxy_read_timeout - it seems to be pretty straightforward. Setting delay between read and write does the job. So I guess my assumptions are wrong and probably I do not understand proxy_connect and proxy_send timeouts properly. Can some explain them to me using above test if possible (or modifying if required).

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• Good Enough Failover Strategy for DNS / MySQL / Email

  - by IMB

  I've asked and read a lot questions regarding DNS failover but the more I read the more complicated it becomes, some people say it's good enough some say it isn't. No clear answers from what I read. I was wondering if we can set it straight once and for all, at least for the requirements of most websites out there. Right now let's assume the following: We don't need really need load-balancing, what we need is a failover solution. We are running a website based on LAMP on a VPS. We need to make sure that the Web Server, MySQL, Email are always accessible if not 99%. Basically here's my idea and questions about it: Web Server: We need at least one failover server (another VPS on a separate data center). Is DNS Failover via Round Robin good, if not, what's the best? And how do you exactly implement it? How do you make the files you upload/delete on Server A is also on Server B? MySQL: I've only read a brief intro to MySQL replication and I assume that I can replicate Server A to Server B and vice versa on the fly right? So just it case Server A fails and Server B is now running, it will continue to work and replicate to Server A when it becomes available. So in essence Server B is now the primary server, and will later on failover to Server A, should a failure happen again. Email: If we are gonna use DNS Failover, using webmail or relying on emails stored on the server is probably not a good idea right? Since some emails might be on Server A while some might be on Server B? I assume a basic email forwarder to a 3rdparty is good enough (like Gmail for example) to ensure all emails are kept in one place. Here's a basic diagram for a better picture: http://i.stack.imgur.com/KWSIi.png

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• Recover badly recorded DVDs

  - by CesarGon

  A few years ago (2003-2005) I bought a Sony USB external DVD recorder for my Dell laptop and I used it to burn a lot of discs. Much later, when I tried to use one of these discs, I realised that I could not read it. The disc behaved as if it was scratched or dirty. I tried on a couple of different DVD drives but got the same effect. Sadly, all the discs that I burnt with that recorder suffer from the same problem. Edit. When I read one of these discs with ImgBurn, I get lots of unrecovered read errors in multiple sectors, even at 1x speed. The sectors that cause read errors seem to be quite random; it's not always the same one. I have no idea what could be wrong with the discs. I doubt that they are scratched or dirty; it would be too much of a coincidence that all the discs that I burnt with that recorder got damaged at the same time. Also, they don't show any physical defects. Is there any way to diagnose what the problem is and, hopefully, recover the contents of the discs? Many thanks.

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• How do I change file protections running XP on a disk from Windows Server?

  - by cdkMoose

  I had a Windows Server 2003 machine running at home, along with my desktop which I use for development. Server went belly up, but since my desktop is reasonably powerful, I figured I would move the disk from the file server (it was OK) into my XP machine to keep all of the files. Disk comes up fine and shows all of the files. I have been getting access denied errors when trying to work with some of the files. When I display attributes in Explorer, none of them are marked Read-Only. When I view properties on the directories, the Read-Only checkbox is not checked, but has a green background(which I thought meant mixed usage for files in the directory). When I click on the checkbox to clear it and click Apply, the disk does some work and all looks well. However, I continue to get the Access Denied errors, the files still don't show any Read-Only attribute and the directory properties shows the green background again on the Read-Only checkbox. I did check the box which says to apply the change to the folder and all files /subfilders under it. I am assuming that the issue relates to userids/permissions carried over from the Server install. So, why does it let me think I can change the attribute when I can't and how can I correct this problem so that the disk correctly recognizes the ids from XP?

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• High data on recv-q buffer and thread lock on java.io.BufferedInputStream in linux

  - by Sagar Patel

  We have a java application running on linux (ubuntu server). We have been facing high recv-q problem since quite some time. Application gets hang and does not read data from socket every few hours. In thread dump, we have found below stack trace. "Receiver-146" daemon prio=10 tid=0x00007fb3fc010000 nid=0x7642 runnable [0x00007fb5906c5000] java.lang.Thread.State: RUNNABLE at java.net.SocketInputStream. socketRead0(Native Method) at java.net.SocketInputStream.read(SocketInputStream.java:150) at java.net.SocketInputStream.read(SocketInputStream.java:121) at java.io.BufferedInputStream.fill(BufferedInputStream.java:235) at java.io.BufferedInputStream.read1(BufferedInputStream.java:275) at java.io.BufferedInputStream.read(BufferedInputStream.java:334) - locked <0x00000007688f1ff0> (a java.io.BufferedInputStream) at org.smpp.TCPIPConnection.receive(TCPIPConnection.java:413) at org.smpp.ReceiverBase.receivePDUFromConnection(ReceiverBase.java:197) at org.smpp.Receiver.receiveAsync(Receiver.java:351) at org.smpp.ReceiverBase.process(ReceiverBase.java:96) at org.smpp.util.ProcessingThread.run(ProcessingThread.java:199) at java.lang.Thread.run(Thread.java:722) We are not able to trace the exact reason behind this? Kindly help. We are using 16 core machine and load on the system is around 30-40 at the time of issue. We use command ss dst <ip> to find out recv-q. Recently we have been facing issues with recv-q size getting hung, were in receive buffer gets stuck at some point of time. But recvQ size is not decreasing and as a result we are losing a lot of hits from the other side, our application is not accepting any data.

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• Can ZFS ACL's be used over NFSv3 on host without /etc/group?

  - by Sandra

  Question at the bottom. Background My server setup is shown below, where I have an LDAP host which have a group called group1 that contains user1, user2. The NAS is FreeBSD 8.3 with ZFS with one zpool and a volume. serv1 gets /etc/passwd and /etc/group from the LDAP host. serv2 gets /etc/passwd from the LDAP host and /etc/group is local and read only. Hence it doesn't not know anything about which groups the LDAP have. Both servers connect to the NAS with NFS 3. What I would like to achieve I would like to be able to create/modify groups in LDAP to allow/deny users read/write access to NFS 3 shared directories on the NAS. Example: group1 should have read/write to /zfs/vol1/project1 and nothing more. Question The problem is that serv2 doesn't have a LDAP controlled /etc/group file. So the only way I can think of to solve this is to use ZFS permissions with inheritance, but I can't figure out how and what the permissions I shall set. Does someone know if this can be solved at all, and if so, any suggestions? +----------------------+ | LDAP | | group1: user1, user2 | +----------------------+ | | | |ldap |ldap |ldap | v | | +-----------+ | | | NAS | | | | /zfs/vol1 | | | +-----------+ | | ^ ^ | | |nfs3 |nfs3| v | | v +-----------------------+ +----------------------------+ | serv1 | | serv2 | | /etc/passwd from LDAP | | /etc/passwd from LDAP | | /etc/group from LDAP | | /etc/group local/read only | +-----------------------+ +----------------------------+

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• Server 2012 - transparent SMB failover without shared discs, possible?

  - by TomTom

  here is the scenario - there is a small set (200gb around) of data that I HAVE to keep available. Those are basically shared VHD images that serve as master images for a lot of our VM's - they then run in differential discs off those. The whole set is "mostly read only". In more detail: A file that IS there and IS used will NEVER change. I may delete files (when absolutely not in use) and add new files, but a file that is there once gets read protection set and that it is until it is retired. Obviously, I need as much uptime as possible. SO FAR we run that by having this directory local on every Hyper-V server. Now I think moving this into our storage fabric. Due to the "it HAS to be there" I pretty much want a share nothing architecture. DFS would be perfect for this - a file never changes, so replication would work nicely. Folders could be replicated to a number of servers, all would reference them from there. Now, that hyper-V supports SMB that could be a good idea to isolate these on a number of servers - we try to move into a scenario where the storage is more centralized. Server 2012 supports always on shares, but it seems that this only works with a clustered disc behind. Is there any way around this for read only file stores? All documentation points to stuff like a shared JBOD - but that would leave me open for file system corruption. I really plan to go quite separately here, vertically - 2 servers, both with SSD only for this, both with their own 2000W separate USV, both with enough bandwidth to handle everything thrown at them (note to everyone tinking this is 10G - this would be SLOW and EXPENSIVE compared to a nice Infiniband backbone). The real crux is that this is an edge case obviously - as the files are read only once in use.

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• zfs pool error, how to determine which drive failed in the past

  - by Kendrick

  I had been copying data from my pool so that I could rebuild it with a different version so that I could go away from solaris 11 and to one that is portable between freebsd/openindia etc. it was copying at 20mb a sec the other day which is about all my desktop drive can handle writing from the network. suddently lastnight it went down to 1.4mb i ran zpool status today and got this. pool: store state: ONLINE status: One or more devices has experienced an unrecoverable error. An attempt was made to correct the error. Applications are unaffected. action: Determine if the device needs to be replaced, and clear the errors using 'zpool clear' or replace the device with 'zpool replace'. see: http://www.sun.com/msg/ZFS-8000-9P scan: none requested config: NAME STATE READ WRITE CKSUM store ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 c8t3d0p0 ONLINE 0 0 2 c8t4d0p0 ONLINE 0 0 10 c8t2d0p0 ONLINE 0 0 0 it is currently a 3 x1tb drive array. what tools would best be used to determine what the error was and which drive is failing. per the admin doc The second section of the configuration output displays error statistics. These errors are divided into three categories: READ – I/O errors occurred while issuing a read request. WRITE – I/O errors occurred while issuing a write request. CKSUM – Checksum errors. The device returned corrupted data as the result of a read request. it was saying low counts could be any thing from a power flux to a disk event but gave no suggestions as to what tools to check and determine with.

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• Updating resources in SharpDX - why can I not map a dynamic texture?

  - by sebf

  I am trying to map a Texture2D resource in DirectX11 via SharpDX. The resource is declared as a ShaderResource, with Default usage and the 'Write' CPU flag specified. My call however fails with a generic exception from SharpDX: _Parent.Context.MapSubresource(_Resource, 0, SharpDX.Direct3D11.MapMode.Write, SharpDX.Direct3D11.MapFlags.None, out stream); I see from this question that it is supported. The MSDN docs and this other question hint that instead of using Context.MapSubresource() I should be using Texture2D.Map(), however, the DirectX11 Texture2D class does not define Map() (though it does for the DX10 equivalent). If I call the above with MapMode.WriteDiscard, the call succeeds but in this case the previous content of the texture is lost, which is no good when I only want to update a section of it. Has the Map() method been removed in DirectX11 or am I looking in the wrong place? Is the MapSubresource() method unsuitable or am I using it wrong?

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• C# HashSet<T>

  - by Ben Griswold

  I hadn’t done much (read: anything) with the C# generic HashSet until I recently needed to produce a distinct collection.  As it turns out, HashSet<T> was the perfect tool. As the following snippet demonstrates, this collection type offers a lot: // Using HashSet<T>: // http://www.albahari.com/nutshell/ch07.aspx var letters = new HashSet<char>("the quick brown fox");   Console.WriteLine(letters.Contains('t')); // true Console.WriteLine(letters.Contains('j')); // false   foreach (char c in letters) Console.Write(c); // the quickbrownfx Console.WriteLine();   letters = new HashSet<char>("the quick brown fox"); letters.IntersectWith("aeiou"); foreach (char c in letters) Console.Write(c); // euio Console.WriteLine();   letters = new HashSet<char>("the quick brown fox"); letters.ExceptWith("aeiou"); foreach (char c in letters) Console.Write(c); // th qckbrwnfx Console.WriteLine();   letters = new HashSet<char>("the quick brown fox"); letters.SymmetricExceptWith("the lazy brown fox"); foreach (char c in letters) Console.Write(c); // quicklazy Console.WriteLine(); The MSDN documentation is a bit light on HashSet<T> documentation but if you search hard enough you can find some interesting information and benchmarks. But back to that distinct list I needed… // MSDN Add // http://msdn.microsoft.com/en-us/library/bb353005.aspx var employeeA = new Employee {Id = 1, Name = "Employee A"}; var employeeB = new Employee {Id = 2, Name = "Employee B"}; var employeeC = new Employee {Id = 3, Name = "Employee C"}; var employeeD = new Employee {Id = 4, Name = "Employee D"};   var naughty = new List<Employee> {employeeA}; var nice = new List<Employee> {employeeB, employeeC};   var employees = new HashSet<Employee>(); naughty.ForEach(x => employees.Add(x)); nice.ForEach(x => employees.Add(x));   foreach (Employee e in employees) Console.WriteLine(e); // Returns Employee A Employee B Employee C The Add Method returns true on success and, you guessed it, false if the item couldn’t be added to the collection.  I’m using the Linq ForEach syntax to add all valid items to the employees HashSet.  It works really great.  This is just a rough sample, but you may have noticed I’m using Employee, a reference type.  Most samples demonstrate the power of the HashSet with a collection of integers which is kind of cheating.  With value types you don’t have to worry about defining your own equality members.  With reference types, you do. internal class Employee {     public int Id { get; set; }     public string Name { get; set; }       public override string ToString()     {         return Name;     }          public bool Equals(Employee other)     {         if (ReferenceEquals(null, other)) return false;         if (ReferenceEquals(this, other)) return true;         return other.Id == Id;     }       public override bool Equals(object obj)     {         if (ReferenceEquals(null, obj)) return false;         if (ReferenceEquals(this, obj)) return true;         if (obj.GetType() != typeof (Employee)) return false;         return Equals((Employee) obj);     }       public override int GetHashCode()     {         return Id;     }       public static bool operator ==(Employee left, Employee right)     {         return Equals(left, right);     }       public static bool operator !=(Employee left, Employee right)     {         return !Equals(left, right);     } } Fortunately, with Resharper, it’s a snap. Click on the class name, ALT+INS and then follow with the handy dialogues. That’s it. Try out the HashSet<T>. It’s good stuff.

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• local wordpress installation, plugin installation and file permissions

  - by user1205935

  I have a local wordpress installation and got everything working, until I tried to install a new plugin. Trying to activate the plugin, wordpress asked me for FTP connection information, which I understood to be a failure of write-access to the plugins directory. Apache runs as www-data, so I ran sudo chown -R www-data: /var/www/wordpress to make the wordpress directory writable for Apache. But now, I cannot edit the files as user anymore. Changing file permissions back to chown -R user: /var/www/wordpress/wp-content/themes, the wordpress dashboard complains again, that it doesn't have sufficient access. I tried various "solutions" online, but none have worked so far. Do I really need to install something like proftp and create an FTP user & password for my local server? Or can I circumvent the problem with some nifty file permission settings, which allow both me and Apache to access/write the files?

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• Developer’s Life – Summary of Superhero Articles

  - by Pinal Dave

  Earlier this year, I wrote an article series where I talked about developer’s life and compared it with Superhero. I have got amazing response to this series and I have been receiving quite a lots of email suggesting that I should write more blog post about them. Currently I am not planning to write more blog post but I will soon continue another series. In this blog post, I have summarized the entire series. Let me know if you want me to write about any superhero. I will see what I can do about that hero. Developer’s Life – Every Developer is a Captain America Captain America was first created as a comic book character in the 1940’s as a way to boost morale during World War II.  Aimed at a children’s audience, his legacy faded away when the war ended.  However, he has recently has a major reboot to become a popular movie character that deals with modern issues. Developer’s Life – Every Developer is the Incredible Hulk The Incredible Hulk is possibly one of the scariest superheroes out there.  All superheroes are meant to be “out of this world” and awe-inspiring, but I think most people will agree with I say The Hulk takes this to the next level.  He is the result of an industrial accident, which is scary enough in it’s own right.  Plus, when mild-mannered Bruce Banner is angered, he goes completely out-of-control and transforms into a destructive monster that he cannot control and has no memories of. Developer’s Life – Every Developer is a Wonder Woman We have focused a lot lately on this “superhero series.”  I love fantasy books and movies, and I feel like there is a lot to be learned from them.  As I am writing this series, though, I have noticed that every super hero I write about is a man.  So today, I would like to talk about the major female super hero – Wonder Woman. Developer’s Life – Every Developer is a Harry Potter Harry Potter might not be a superhero in the traditional sense, but I believe he still has a lot to teach us and show us about life as a developer.  If you have been living under a rock for the last 17 years, you might not know that Harry Potter is the main character in an extremely popular series of books and movies documenting the education and tribulation of a young wizard (and his friends). Developer’s Life – Every Developer is Like Transformers Transformers may not be superheroes – they don’t wear capes, they don’t have amazing powers outside of their size and folding ability, they’re not even human (technically).  Part of their enduring popularity is that while we are enjoying over-the-top movies, we are learning about good leadership and strong personal skills. Developer’s Life – Every Developer is a Iron Man Iron Man is another superhero who is not naturally “super,” but relies on his brain (and money) to turn him into a fighting machine.  While traditional superheroes are still popular, a three-movie franchise and incorporation into the new Avengers series shows that Iron Man is popular enough on his own. Developer’s Life – Every Developer is a Sherlock Holmes I have been thinking a lot about how developers are like super heroes, and I have written two blog posts now comparing them to Spiderman and Superman.  I have a lot of love and respect for developers, and I hope that they are enjoying these articles, and others are learning a little bit about the profession.  There is another fictional character who, while not technically asuper hero, is very powerful, and I also think stands as a good example of a developer. That character is Sherlock Holmes.  Sherlock Holmes is a British detective, first made popular at the turn of the 19thcentury by author Sir Arthur Conan Doyle.  The original Sherlock Holmes was a brilliant detective who could solve the most mind-boggling crime through simple observations and deduction. Developer’s Life – Every Developer is a Chhota Bheem Chhota Bheem is a cartoon character that is extremely popular where I live.  He is my daughter’s favorite characters.  I like to say that children love Chhota Bheem more than their parents – it is lucky for us he is not real!  Children love Chhota Bheem because he is the absolute “good guy.”  He is smart, loyal, and strong.  He and his friends live in Dholakpur and fight off their many enemies – and always win – in every episode.  In each episode, they learn something about friendship, bravery, and being kind to others.  Chhota Bheem is a good role model for children, and I think that he is a good role model for developers are well. Developer’s Life – Every Developer is a Batman Batman is one of the darkest superheroes in the fantasy canon.  He does not come to his powers through any sort of magical coincidence or radioactive insect, but through a lot of psychological scarring caused by witnessing the death of his parents.  Despite his dark back story, he possesses a lot of admirable abilities that I feel bear comparison to developers. Developer’s Life – Every Developer is a Superman I enjoyed comparing developers to Spiderman so much, that I have decided to continue the trend and encourage some of my favorite people (developers) with another favorite superhero – Superman.  Superman is probably the most famous superhero – and one of the most inspiring. Developer’s Life – Every Developer is a Spiderman I have to admit, Spiderman is my favorite superhero.  The most recent movie recently was released in theaters, so it has been at the front of my mind for some time. Spiderman was my favorite superhero even before the latest movie came out, but of course I took my whole family to see the movie as soon as I could!  Every one of us loved it, including my daughter.  We all left the movie thinking how great it would be to be Spiderman.  So, with that in mind, I started thinking about how we are like Spiderman in our everyday lives, especially developers. I would like to know which Superhero is your favorite hero! Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Developer, Superhero

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• CodePlex Daily Summary for Tuesday, March 09, 2010

  CodePlex Daily Summary for Tuesday, March 09, 2010New Projects.NET Excel Wrapper - Read, Write, Edit & Automate Excel Files in .NET with ease: .NET Excel Wrapper encapsulates the complexity of working with multiple Excel objects giving you one central point to do all your processing. It h...Advancement Voyage: Advancement Voyage is a high quality RPG experience that provides all the advancement and voyaging that a player could hope for.ASP.Net Routing configuration: ASP.NET routing configuration enables you to configure the routes in the web.config bbinjest: bbinjestBuildUp: BuildUp is a build number increment tool for C# .net projects. It is run as a post build step in Visual Studio.Controlled Vocabulary: This project is devoted to creating tools to assist with Controlling Vocabulary in communication. The initial delivery is an Outlook 2010 Add-in w...CycleList: A replacement for the WPF ListBox Control. Displays only a single item and allows the user to change the selected item by clicking on it once. Very...Forensic Suite: A suite of security softwareFREE DNN Chat Module for 123 Flash Chat -- Embed FREE Chat Room!: 123 Flash Chat is a live chat solution and its DotNetNuke Chat Module helps to embed a live chat room into website with DotNetNuke(DNN) integrated ...HouseFly experimental controls: Experimental controls for use in HouseFly.ICatalogAll: junkMidiStylus: MidiStylus allows you to control MIDI-enabled hardware or software using your pressure-sensitive pen tablet. The program maps the X position, Y po...myTunes: Search for your favorite artistsNColony - Pluggable Socialism?: NColony will maximize the use of MEF to create flexible application architectures through a suite of plug-in solutions. If MEF is an outlet for plu...Network Monitor Decryption Expert: NmDecrypt is a Network Monitor Expert which when given a trace with encrypted frames, a security certificate, and a passkey will create a new trace...occulo: occulo is a free steganography program, meant to embed files within images with optional encrytion. Open Ant: A implementation of a Open Source Ant which is created to show what is possible in the serious game AntMe! The First implementation of that ProjectProgramming Patterns by example: Design patterns provide solutions to common software design problems. This project will contain samples, written in c# and ruby, of each design pat...project4k: Developing bulk mail system storing email informationQuail - Selenium Remote Control Made Easy: Quail makes it easy for Quality Assurance departments write automated tests against web applications. Both HTML and Silverlight applications can b...RedBulb for XNA Framework: RedBulb is a collection of utility functions and classes that make writing games with XNA a lot easier. Key features: Console,GUI (Labels, Buttons,...RegExpress: RegExpress is a WPF application that combines interactive demos of regular expressions with slide content. This was designed for a user group prese...RemoveFolder: Small utility program to remove empty foldersScrumTFS: ScrumTFSSharePoint - Open internal link in new window list definition: A simple SharePoint list definition to render SharePoint internal links with the option to open them in a new window.SqlSiteMap4MVC: SqlSiteMapProvider for ASP.Net MVC.T Sina .NET Client: t.sina.com.cn api 新浪微博APITest-Lint-Extensions: Test Lint is a free Typemock VS 2010 Extension that finds common problems in your unit tests as you type them. this project will host extensions ...ThinkGearNET: ThinkGearNET is a library for easy usage of the Neurosky Mindset headset from .NET .Wiki to Maml: This project enables you to write wiki syntax and have it converted into MAML syntax for Sandcastle documentation projects.WPF Undo/Redo Framework: This project attempts to solve the age-old programmer problem of supporting unlimited undo/redo in an application, in an easily reusable manner. Th...WPFValidators: WPF Validators Validações de campos para WPFWSP Listener: The WSP listener is a windows service application which waits for new WSC and WSP files in a specific folder. If a new WSC and WSP file are added, ...New Releases.NET Excel Wrapper - Read, Write, Edit & Automate Excel Files in .NET with ease: First Release: This is the first release which includes the main library release..NET Excel Wrapper - Read, Write, Edit & Automate Excel Files in .NET with ease: Updated Version: New Features:SetRangeValue using multidimensional array Print current worksheet Print all worksheets Format ranges background, color, alig...ArkSwitch: ArkSwitch v1.1.2: This release removes all memory reporting information, and is focused on stability.BattLineSvc: V2.1: - Fixed a bug where on system start-up, it would pop up a notification box to let you know the service started. Annoying! And fixed! - Fixed the ...BuildUp: BuildUp 1.0 Alpha 1: Use at your own risk!Not yet feature complete. Basic build incrementing and attribute overriding works. Still working on cascading build incremen...Controlled Vocabulary: 1.0.0.1: Initial Alpha Release. System Requirements Outlook 2010 .Net Framework 3.5 Installation 1. Close Outlook (Use Task Manager to ensure no running i...CycleList: CycleList: The binaries contain the .NET 3.5 DLL ONLY. Please download source for usage examples.FluentNHibernate.Search: 0.3 Beta: 0.3 Beta take the following changes : Mappings : - Field Mapping without specifying "Name" - Id Mapping without specifiying "Field" - Builtin Anal...FREE DNN Chat Module for 123 Flash Chat -- Embed FREE Chat Room!: 123 Flash Chat DNN Chat Module: With FREE DotNetNuke Chat Module of 123 Flash Chat, webmaster will be assist to add a chat room into DotNetNuke instantly and help to attract more ...GameStore League Manager: League Manager 1.0 release 3: This release includes a full installer so that you can get your league running faster and generate interest quicker.iExporter - iTunes playlist exporting: iExporter gui v2.3.1.0 - console v1.2.1.0: Paypal donate! Solved a big bug for iExporter ( Gui & Console ) When a track isn't located under the main iTunes library, iExporter would crash! ...jQuery.cssLess: jQuery.cssLess 0.3: New - Removed the dependency from XRegExp - Added comment support (both CSS style and C style) - Optimised it for speed - Added speed test TOD...jQuery.cssLess: jQuery.cssLess 0.4: NEW - @import directive - preserving of comments in the resulting CSS - code refactoring - more class oriented approach TODO - implement operation...MapWindow GIS: MapWindow 6.0 msi (March 8): Rewrote the shapefile saving code in the indexed case so that it uses the shape indices rather than trying to create features. This should allow s...MidiStylus: MidiStylus 0.5.1: MidiStylus Beta 0.5.1 This release contains basic functionality for transmitting MIDI data based on X position, Y position, and pressure value rea...MiniTwitter: 1.09.1: MiniTwitter 1.09.1 更新内容 修正 URL に & が含まれている時に短縮 URL がおかしくなるバグを修正Mosaictor: first executable: .exe file of the app in its current state. Mind you that this will likely be highly unstable due to heaps of uncaught errors.MvcContrib a Codeplex Foundation project: T4MVC: T4MVC is a T4 template that generates strongly typed helpers for ASP.NET MVC. You can download it below, and check out the documention here.N2 CMS: 2.0 beta: Major Changes ASP.NET MVC 2 templates Refreshed management UI LINQ support Performance improvements Auto image resize Upgrade Make a comp...NotesForGallery: ASP.NET AJAX Photo Gallery Control: NotesForGallery 2.0: PresentationNotesForGallery is an open source control on top of the Microsoft ASP.NET AJAX framework for easy displaying image galleries in the as...occulo: occulo 0.1 binaries: Windows binaries. Tested on Windows XP SP2.occulo: occulo 0.1 source: Initial source release.Open NFe: DANFE 1.9.5: Ajuste de layout e correção dos campos de ISS.patterns & practices Web Client Developer Guidance: Web Application Guidance -- March 8th Drop: This iteration we focused on documentation and bug fixes.PoshConsole: PoshConsole 2.0 Beta: With this release, I am refocusing PoshConsole... 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However movement of rotation is quite good in this version thanks to clea...SCSI Interface for Multimedia and Block Devices: Release 9 - Improvements and Bug Fixes: Changes I have made in this version: Fixed INQUIRY command timeout problem Lowered ISOBurn's memory usage significantly by not explicitly setting...SharePoint - Open internal link in new window list definition: Open link in new window list definition: First release, with english and italian localization supportSharePoint Outlook Connector: Version 1.2.3.2: Few bug fixing and some ui enhancementsSysI: sysi, release build: Better than ever -- now allows for escalation to adminThe Silverlight Hyper Video Player [http://slhvp.com]: Beta 1: Beta (1.1) The code is ready for intensive testing. 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• SQL SERVER – T-SQL Script to Take Database Offline – Take Database Online

  - by pinaldave

  Blog reader Joyesh Mitra recently left a comment to one of my very old posts about SQL SERVER – 2005 Take Off Line or Detach Database, which I have written focusing on taking the database offline. However, I did not include how to bring the offline database to online in that post. The reason I did not write it was that I was thinking it was a very simple script that almost everyone knows. However, it seems to me that there is something I found advanced in this procedure that is not simple for other people. We all have different expertise and we all try to learn new things, so I do not see any reason as to not write about the script to take the database online. -- Create Test DB CREATE DATABASE [myDB] GO -- Take the Database Offline ALTER DATABASE [myDB] SET OFFLINE WITH ROLLBACK IMMEDIATE GO -- Take the Database Online ALTER DATABASE [myDB] SET ONLINE GO -- Clean up DROP DATABASE [myDB] GO Joyesh let me know if this answers your question. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• JavaScript Data Binding Frameworks

  - by dwahlin

  Data binding is where it’s at now days when it comes to building client-centric Web applications. Developers experienced with desktop frameworks like WPF or web frameworks like ASP.NET, Silverlight, or others are used to being able to take model objects containing data and bind them to UI controls quickly and easily. When moving to client-side Web development the data binding story hasn’t been great since neither HTML nor JavaScript natively support data binding. This means that you have to write code to place data in a control and write code to extract it. Although it’s certainly feasible to do it from scratch (many of us have done it this way for years), it’s definitely tedious and not exactly the best solution when it comes to maintenance and re-use. Over the last few years several different script libraries have been released to simply the process of binding data to HTML controls. In fact, the subject of data binding is becoming so popular that it seems like a new script library is being released nearly every week. Many of the libraries provide MVC/MVVM pattern support in client-side JavaScript apps and some even integrate directly with server frameworks like Node.js. Here’s a quick list of a few of the available libraries that support data binding (if you like any others please add a comment and I’ll try to keep the list updated): AngularJS MVC framework for data binding (although closely follows the MVVM pattern). Backbone.js MVC framework with support for models, key/value binding, custom events, and more. Derby Provides a real-time environment that runs in the browser an in Node.js. The library supports data binding and templates. Ember Provides support for templates that automatically update as data changes. JsViews Data binding framework that provides “interactive data-driven views built on top of JsRender templates”. jQXB Expression Binder Lightweight jQuery plugin that supports bi-directional data binding support. KnockoutJS MVVM framework with robust support for data binding. For an excellent look at using KnockoutJS check out John Papa’s course on Pluralsight. Meteor End to end framework that uses Node.js on the server and provides support for data binding on  the client. Simpli5 JavaScript framework that provides support for two-way data binding. WinRT with HTML5/JavaScript If you’re building Windows 8 applications using HTML5 and JavaScript there’s built-in support for data binding in the WinJS library.   I won’t have time to write about each of these frameworks, but in the next post I’m going to talk about my (current) favorite when it comes to client-side JavaScript data binding libraries which is AngularJS. AngularJS provides an extremely clean way – in my opinion - to extend HTML syntax to support data binding while keeping model objects (the objects that hold the data) free from custom framework method calls or other weirdness. While I’m writing up the next post, feel free to visit the AngularJS developer guide if you’d like additional details about the API and want to get started using it.

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• Searching for tasks with code – Executables and Event Handlers

  Searching packages or just enumerating through all tasks is not quite as straightforward as it may first appear, mainly because of the way you can nest tasks within other containers. You can see this illustrated in the sample package below where I have used several sequence containers and loops. To complicate this further all containers types, including packages and tasks, can have event handlers which can then support the full range of nested containers again. Towards the lower right, the task called SQL In FEL also has an event handler not shown, within which is another Execute SQL Task, so that makes a total of 6 Execute SQL Tasks 6 tasks spread across the package. In my previous post about such as adding a property expressionI kept it simple and just looked at tasks at the package level, but what if you wanted to find any or all tasks in a package? For this post I've written a console program that will search a package looking at all tasks no matter how deeply nested, and check to see if the name starts with "SQL". When it finds a matching task it writes out the hierarchy by name for that task, starting with the package and working down to the task itself. The output for our sample package is shown below, note it has found all 6 tasks, including the one on the OnPreExecute event of the SQL In FEL task TaskSearch v1.0.0.0 (1.0.0.0) Copyright (C) 2009 Konesans Ltd Processing File - C:\Projects\Alpha\Packages\MyPackage.dtsx MyPackage\FOR Counter Loop\SQL In Counter Loop MyPackage\SEQ For Each Loop Wrapper\FEL Simple Loop\SQL In FEL MyPackage\SEQ For Each Loop Wrapper\FEL Simple Loop\SQL In FEL\OnPreExecute\SQL On Pre Execute for FEL SQL Task MyPackage\SEQ Top Level\SEQ Nested Lvl 1\SEQ Nested Lvl 2\SQL In Nested Lvl 2 MyPackage\SEQ Top Level\SEQ Nested Lvl 1\SQL In Nested Lvl 1 #1 MyPackage\SEQ Top Level\SEQ Nested Lvl 1\SQL In Nested Lvl 1 #2 6 matching tasks found in package. The full project and code is available for download below, but first we can walk through the project to highlight the most important sections of code. This code has been abbreviated for this description, but is complete in the download. First of all we load the package, and then start by looking at the Executables for the package. // Load the package file Application application = new Application(); using (Package package = application.LoadPackage(filename, null)) { int matchCount = 0; // Look in the package's executables ProcessExecutables(package.Executables, ref matchCount); ... // // ... // Write out final count Console.WriteLine("{0} matching tasks found in package.", matchCount); } The ProcessExecutables method is a key method, as an executable could be described as the the highest level of a working functionality or container. There are several of types of executables, such as tasks, or sequence containers and loops. To know what to do next we need to work out what type of executable we are dealing with as the abbreviated version of method shows below. private static void ProcessExecutables(Executables executables, ref int matchCount) { foreach (Executable executable in executables) { TaskHost taskHost = executable as TaskHost; if (taskHost != null) { ProcessTaskHost(taskHost, ref matchCount); ProcessEventHandlers(taskHost.EventHandlers, ref matchCount); continue; } ... // // ... ForEachLoop forEachLoop = executable as ForEachLoop; if (forEachLoop != null) { ProcessExecutables(forEachLoop.Executables, ref matchCount); ProcessEventHandlers(forEachLoop.EventHandlers, ref matchCount); continue; } } } As you can see if the executable we find is a task we then call out to our ProcessTaskHost method. As with all of our executables a task can have event handlers which themselves contain more executables such as task and loops, so we also make a call out our ProcessEventHandlers method. The other types of executables such as loops can also have event handlers as well as executables. As shown with the example for the ForEachLoop we call the same ProcessExecutables and ProcessEventHandlers methods again to drill down into the hierarchy of objects that the package may contain. This code needs to explicitly check for each type of executable (TaskHost, Sequence, ForLoop and ForEachLoop) because whilst they all have an Executables property this is not from a common base class or interface. This example was just a simple find a task by its name, so ProcessTaskHost really just does that. We also get the hierarchy of objects so we can write out for information, obviously you can adapt this method to do something more interesting such as adding a property expression. private static void ProcessTaskHost(TaskHost taskHost, ref int matchCount) { if (taskHost == null) { return; } // Check if the task matches our match name if (taskHost.Name.StartsWith(TaskNameFilter, StringComparison.OrdinalIgnoreCase)) { // Build up the full object hierarchy of the task // so we can write it out for information StringBuilder path = new StringBuilder(); DtsContainer container = taskHost; while (container != null) { path.Insert(0, container.Name); container = container.Parent; if (container != null) { path.Insert(0, "\\"); } } // Write the task path // e.g. Package\Container\Event\Task Console.WriteLine(path); Console.WriteLine(); // Increment match counter for info matchCount++; } } Just for completeness, the other processing method we covered above is for event handlers, but really that just calls back to the executables. This same method is called in our main package method, but it was omitted for brevity here. private static void ProcessEventHandlers(DtsEventHandlers eventHandlers, ref int matchCount) { foreach (DtsEventHandler eventHandler in eventHandlers) { ProcessExecutables(eventHandler.Executables, ref matchCount); } } As hopefully the code demonstrates, executables (Microsoft.SqlServer.Dts.Runtime.Executable) are the workers, but within them you can nest more executables (except for task tasks).Executables themselves can have event handlers which can in turn hold more executables. I have tried to illustrate this highlight the relationships in the following diagram. Download Sample code project TaskSearch.zip (11KB)

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• What is the objective of unit testing?

  - by user728750

  I've been working with C# for the last 2 years, and I've never done any unit testing. I just need to know what the objective of unit testing is. What kind of results do we expect from unit testing? Is code quality checked by unit testing? In my view, unit testing is the job of testers; if that is true, then as a developer why would I need to write test code if the tester does the unit testing? Why should I write extra code for testing? Do I need to maintain a separate copy of a project for unit testing?

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• My Interview with Microsoft

  - by Victor Hurdugaci

  This post is for those who want to apply or have already applied (but not finished the interview) for a Microsoft Job. The recruitment process is quite similar for everyone and consists of a few steps. Application E-Mail Interview Phone Interview On Site Interview I will tell you my story and how I went through the four phases. 1. Application My blog's title (Ex Nihilo Nihil Fit) means "Nothing Comes Out of Nothing". You can't get a job at Microsoft by not doing anything - this is true for anything else. The first step you need to complete is the application process. For this, many options are available. You can... ... apply online on Microsoft's Careers website as I did ... send your CV to different e-mail addresses (there are some dedicated e-mails for different positions) ... apply through some 3rd party organization (job shop, campus recruitment, job agency, etc) On MS Careers you just have to post your CV and choose the job you want. That's all! No recommendation letter, no cover letter, no nothing. Of course, not every CV passes the selection process. Here are some tips for improving your resume (worked for me): Don't write it just before applying! Write a draft version, wait a few days and then review it. This way you will find a lot of mistakes and stupid things you wrote initially. If you review it immediately after writing, your mind will not be criticism oriented and will just ignore mistakes. Repeat the write-wait-review process as many times as necessary, until you find that the review revealed no mistakes. After you did the final review and the CV is bullet-proof, ask others to review it. They will definitely find inconsistencies and mistakes and this will make you feel stupid. This is good because will open your eyes will make you go into an 'I want to improve' mode. You'll try to correct everything. After you come up with a modified version go again through steps 1 and 2. Repeat this as many times as necessary. [Special thanks to Lucian Sasu, Nadia Comanici, Andrei Ciobanu, Monica Balan and Lavinia Tanase for reviewing my CV!] Make it short and give only relevant facts. Initially, I come up with a 5 pages CV because I wrote every single technology with which I worked. There were a lot irrelevant things, I wrote Windows Workflow Foundation just because I played with it for a few days. I added extensive descriptions for every project, made a personal details section (name, birth date, address, etc) of 1/2 page. Others suggested to cut everything that was not necessary. You don't need to give extensive descriptions, just add a few words. For example, I wrote "VS Image Visualizer - Visual Studio 2008 debug visualizer for images" and added a link to the project's page - you submit formatted andcan embed links. Add something that makes it different. I don't know if this makes a difference, but I added some lines to separate items just like in the picture below. Definitely Microsoft gets thousands of CVs per day. You need something special. Don't lie! Tell exactly what you did and what is the proficiency level of your skills. For example, don't write "Advanced" for UML if you don't know the difference between composition and aggregation. Be realistic and don't under/over estimate yourself. Use the spell chick. Make sure everything is written in correct English and there are no grammar/spelling mistakes. Noddy likes a WC with grammar mi takes. You mght fail just because of that. Once you completed your CV, choose the job that suits best your needs, apply and wait... The waiting is a problem because all these big companies like Microsoft, Google, Mozilla, Apple, etc. will contact you only if they find something interesting in your application. If you're not suitable, then no rejection is sent. I applied for an Intern Software Development Engineer position at Microsoft Redmond. I cannot apply for a full time position because I want to finish the master program on time, in the next summer - an internship is just what I need. 2. E-Mail Interview January 20, 2010. Two months since I submitted the CV. I wasn't hoping anymore that MS will contact me, when I got an e-mail titled: "Victor Hurdugaci ES DK" from Holly Peterson saying: Read more >>

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• Problem with RAID5 (mdadm) - disk detached

  - by poscaman

  Having these lines in /var/log/syslog Apr 18 16:53:05 Server kernel: [4487878.816036] ata4: EH in SWNCQ mode,QC:qc_active 0x1 sactive 0x1 Apr 18 16:53:05 Server kernel: [4487878.816058] ata4: SWNCQ:qc_active 0x1 defer_bits 0x0 last_issue_tag 0x0 Apr 18 16:53:05 Server kernel: [4487878.816059] dhfis 0x1 dmafis 0x1 sdbfis 0x0 Apr 18 16:53:05 Server kernel: [4487878.816093] ata4: ATA_REG 0x40 ERR_REG 0x0 Apr 18 16:53:05 Server kernel: [4487878.816108] ata4: tag : dhfis dmafis sdbfis sacitve Apr 18 16:53:05 Server kernel: [4487878.816125] ata4: tag 0x0: 1 1 0 1 Apr 18 16:53:05 Server kernel: [4487878.816150] ata4.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x6 frozen Apr 18 16:53:05 Server kernel: [4487878.816178] ata4.00: failed command: WRITE FPDMA QUEUED Apr 18 16:53:05 Server kernel: [4487878.816199] ata4.00: cmd 61/08:00:00:88:e0/00:00:e8:00:00/40 tag 0 ncq 4096 out Apr 18 16:53:05 Server kernel: [4487878.816200] res 40/00:00:01:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout) Apr 18 16:53:05 Server kernel: [4487878.816253] ata4.00: status: { DRDY } Apr 18 16:53:05 Server kernel: [4487878.816272] ata4: hard resetting link Apr 18 16:53:05 Server kernel: [4487878.816274] ata4: nv: skipping hardreset on occupied port Apr 18 16:53:06 Server kernel: [4487879.676029] ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 18 16:53:07 Server kernel: [4487880.416749] ata4.00: n_sectors mismatch 3907029168 != 268435455 Apr 18 16:53:07 Server kernel: [4487880.416752] ata4.00: revalidation failed (errno=-19) Apr 18 16:53:07 Server kernel: [4487880.416773] ata4.00: limiting speed to UDMA/133:PIO2 Apr 18 16:53:11 Server kernel: [4487884.676024] ata4: hard resetting link Apr 18 16:53:11 Server kernel: [4487884.676027] ata4: nv: skipping hardreset on occupied port Apr 18 16:53:12 Server kernel: [4487885.144032] ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 18 16:53:12 Server kernel: [4487885.240185] ata4.00: failed to IDENTIFY (INIT_DEV_PARAMS failed, err_mask=0x80) Apr 18 16:53:12 Server kernel: [4487885.240190] ata4.00: revalidation failed (errno=-5) Apr 18 16:53:12 Server kernel: [4487885.240210] ata4.00: disabled Apr 18 16:53:17 Server kernel: [4487890.144023] ata4: hard resetting link Apr 18 16:53:17 Server kernel: [4487891.024033] ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 18 16:53:17 Server kernel: [4487891.033357] ata4.00: ATA-8: WDC WD20EARS-00S8B1, 80.00A80, max UDMA/133 Apr 18 16:53:17 Server kernel: [4487891.033360] ata4.00: 3907029168 sectors, multi 1: LBA48 NCQ (depth 31/32) Apr 18 16:53:17 Server kernel: [4487891.048347] ata4.00: configured for UDMA/133 Apr 18 16:53:17 Server kernel: [4487891.048361] sd 3:0:0:0: [sdc] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Apr 18 16:53:17 Server kernel: [4487891.048365] sd 3:0:0:0: [sdc] Sense Key : Aborted Command [current] [descriptor] Apr 18 16:53:17 Server kernel: [4487891.048369] Descriptor sense data with sense descriptors (in hex): Apr 18 16:53:17 Server kernel: [4487891.048371] 72 0b 00 00 00 00 00 0c 00 0a 80 00 00 00 00 00 Apr 18 16:53:17 Server kernel: [4487891.048378] 00 00 00 00 Apr 18 16:53:17 Server kernel: [4487891.048382] sd 3:0:0:0: [sdc] Add. Sense: No additional sense information Apr 18 16:53:17 Server kernel: [4487891.048385] sd 3:0:0:0: [sdc] CDB: Write(10): 2a 00 e8 e0 88 00 00 00 08 00 Apr 18 16:53:17 Server kernel: [4487891.048393] end_request: I/O error, dev sdc, sector 3907028992 Apr 18 16:53:17 Server kernel: [4487891.048420] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048440] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048458] end_request: I/O error, dev sdc, sector 3907028992 Apr 18 16:53:17 Server kernel: [4487891.048477] md: super_written gets error=-5, uptodate=0 Apr 18 16:53:17 Server kernel: [4487891.048482] raid5: Disk failure on sdc, disabling device. Apr 18 16:53:17 Server kernel: [4487891.048483] raid5: Operation continuing on 3 devices. Apr 18 16:53:17 Server kernel: [4487891.048525] ata4: EH complete Apr 18 16:53:17 Server kernel: [4487891.048554] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048576] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048596] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048615] sd 3:0:0:0: [sdc] READ CAPACITY(16) failed Apr 18 16:53:17 Server kernel: [4487891.048617] sd 3:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK Apr 18 16:53:17 Server kernel: [4487891.048620] sd 3:0:0:0: [sdc] Sense not available. Apr 18 16:53:17 Server kernel: [4487891.048624] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048643] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048663] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048681] sd 3:0:0:0: [sdc] READ CAPACITY failed Apr 18 16:53:17 Server kernel: [4487891.048683] sd 3:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK Apr 18 16:53:17 Server kernel: [4487891.048685] sd 3:0:0:0: [sdc] Sense not available. Apr 18 16:53:17 Server kernel: [4487891.048689] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048709] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048800] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.048860] sd 3:0:0:0: rejecting I/O to offline device Apr 18 16:53:17 Server kernel: [4487891.049028] sd 3:0:0:0: [sdc] Asking for cache data failed Apr 18 16:53:17 Server kernel: [4487891.049048] sd 3:0:0:0: [sdc] Assuming drive cache: write through Apr 18 16:53:17 Server kernel: [4487891.049071] sdc: detected capacity change from 2000398934016 to 0 Apr 18 16:53:17 Server kernel: [4487891.049080] ata4.00: detaching (SCSI 3:0:0:0) Apr 18 16:53:18 Server kernel: [4487891.061149] sd 3:0:0:0: [sdc] Stopping disk Apr 18 16:53:18 Server kernel: [4487891.485492] RAID5 conf printout: Apr 18 16:53:18 Server kernel: [4487891.485496] --- rd:4 wd:3 Apr 18 16:53:18 Server kernel: [4487891.485500] disk 0, o:1, dev:sdb Apr 18 16:53:18 Server kernel: [4487891.485502] disk 1, o:0, dev:sdc Apr 18 16:53:18 Server kernel: [4487891.485504] disk 2, o:1, dev:sdd Apr 18 16:53:18 Server kernel: [4487891.485506] disk 3, o:1, dev:sde Apr 18 16:53:18 Server kernel: [4487891.497014] RAID5 conf printout: Apr 18 16:53:18 Server kernel: [4487891.497016] --- rd:4 wd:3 Apr 18 16:53:18 Server kernel: [4487891.497018] disk 0, o:1, dev:sdb Apr 18 16:53:18 Server kernel: [4487891.497019] disk 2, o:1, dev:sdd Apr 18 16:53:18 Server kernel: [4487891.497021] disk 3, o:1, dev:sde Apr 18 16:53:18 Server kernel: [4487891.838719] scsi 3:0:0:0: Direct-Access ATA WDC WD20EARS-00S 80.0 PQ: 0 ANSI: 5 Apr 18 16:53:18 Server kernel: [4487891.838886] sd 3:0:0:0: Attached scsi generic sg3 type 0 Apr 18 16:53:18 Server kernel: [4487891.838911] sd 3:0:0:0: [sdf] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB) Apr 18 16:53:18 Server kernel: [4487891.838964] sd 3:0:0:0: [sdf] Write Protect is off Apr 18 16:53:18 Server kernel: [4487891.838967] sd 3:0:0:0: [sdf] Mode Sense: 00 3a 00 00 Apr 18 16:53:18 Server kernel: [4487891.838988] sd 3:0:0:0: [sdf] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Apr 18 16:53:20 Server kernel: [4487891.839147] sdf: unknown partition table Apr 18 16:53:20 Server kernel: [4487893.130026] sd 3:0:0:0: [sdf] Attached SCSI disk Right now, i'm unable to do anything on /dev/sdc. Is there any way to try to re-attach it? I don't want to power-down the server unless absolutely necessary System: Debian Stable 2.6.32-5-amd64 mdadm version 3.1.4-1+8efb9d1 cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 sdb[0] sdc[4](F) sde[3] sdd[2] 5860543488 blocks level 5, 64k chunk, algorithm 2 [4/3] [U_UU] unused devices: <none> mdadm --examine --scan ARRAY /dev/md0 UUID=1a7744b5:912ec7af:f82a9565:e3b453b4

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• SQL SERVER – PAGEIOLATCH_DT, PAGEIOLATCH_EX, PAGEIOLATCH_KP, PAGEIOLATCH_SH, PAGEIOLATCH_UP – Wait Type – Day 9 of 28

  - by pinaldave

  It is very easy to say that you replace your hardware as that is not up to the mark. In reality, it is very difficult to implement. It is really hard to convince an infrastructure team to change any hardware because they are not performing at their best. I had a nightmare related to this issue in a deal with an infrastructure team as I suggested that they replace their faulty hardware. This is because they were initially not accepting the fact that it is the fault of their hardware. But it is really easy to say “Trust me, I am correct”, while it is equally important that you put some logical reasoning along with this statement. PAGEIOLATCH_XX is such a kind of those wait stats that we would directly like to blame on the underlying subsystem. Of course, most of the time, it is correct – the underlying subsystem is usually the problem. From Book On-Line: PAGEIOLATCH_DT Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Destroy mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_EX Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Exclusive mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_KP Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Keep mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_SH Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Shared mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_UP Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Update mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_XX Explanation: Simply put, this particular wait type occurs when any of the tasks is waiting for data from the disk to move to the buffer cache. ReducingPAGEIOLATCH_XX wait: Just like any other wait type, this is again a very challenging and interesting subject to resolve. Here are a few things you can experiment on: Improve your IO subsystem speed (read the first paragraph of this article, if you have not read it, I repeat that it is easy to say a step like this than to actually implement or do it). This type of wait stats can also happen due to memory pressure or any other memory issues. Putting aside the issue of a faulty IO subsystem, this wait type warrants proper analysis of the memory counters. If due to any reasons, the memory is not optimal and unable to receive the IO data. This situation can create this kind of wait type. Proper placing of files is very important. We should check file system for the proper placement of files – LDF and MDF on separate drive, TempDB on separate drive, hot spot tables on separate filegroup (and on separate disk), etc. Check the File Statistics and see if there is higher IO Read and IO Write Stall SQL SERVER – Get File Statistics Using fn_virtualfilestats. It is very possible that there are no proper indexes on the system and there are lots of table scans and heap scans. Creating proper index can reduce the IO bandwidth considerably. If SQL Server can use appropriate cover index instead of clustered index, it can significantly reduce lots of CPU, Memory and IO (considering cover index has much lesser columns than cluster table and all other it depends conditions). You can refer to the two articles’ links below previously written by me that talk about how to optimize indexes. Create Missing Indexes Drop Unused Indexes Updating statistics can help the Query Optimizer to render optimal plan, which can only be either directly or indirectly. I have seen that updating statistics with full scan (again, if your database is huge and you cannot do this – never mind!) can provide optimal information to SQL Server optimizer leading to efficient plan. Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All of the discussions of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• Cold Start

  - by antony.reynolds

  Well we had snow drifts 3ft deep on Saturday so it must be spring time.  In preparation for Spring we decided to move the lawn tractor.  Of course after sitting in the garage all winter it refused to start.  I then come into the office and need to start my 11g SOA Suite installation.  I thought about this and decided my tractor might be cranky but at least I can script the startup of my SOA Suite 11g installation. So with this in mind I created 6 scripts.  I created them for Linux but they should translate to Windows without too many problems.  This is left as an exercise to the reader, note you will have to hardcode more than I did in the Linux scripts and create separate script files for the sqlplus and WLST sections. Order to start things I believe there should be order in all things, especially starting the SOA Suite.  So here is my preferred order. Start Database This is need by EM and the rest of SOA Suite so best to start it before the Admin Server and managed servers. Start Node Manager on all machines This is needed if you want the scripts to work across machines. Start Admin Server Once this is done in theory you can manually stat the managed servers using WebLogic console.  But then you have to wait for console to be available.  Scripting it all is quicker and easier way of starting. Start Managed Servers & Clusters Best to start them one per physical machine at a time to avoid undue load on the machines.  Non-clustered install will have just soa_server1 and bam_serv1 by default.  Clusters will have at least SOA and BAM clusters that can be started as a group or individually.  I have provided scripts for standalone servers, but easy to change them to work with clusters. Starting Database I have provided a very primitive script (available here) to start the database, the listener and the DB console.  The section highlighted in red needs to match your database name. #!/bin/sh echo "##############################" echo "# Setting Oracle Environment #" echo "##############################" . oraenv <<-EOF orcl EOF echo "#####################" echo "# Starting Database #" echo "#####################" sqlplus / as sysdba <<-EOF startup exit EOF echo "#####################" echo "# Starting Listener #" echo "#####################" lsnrctl start echo "######################" echo "# Starting dbConsole #" echo "######################" emctl start dbconsole read -p "Hit <enter> to continue" Starting SOA Suite My script for starting the SOA Suite (available here) breaks the task down into five sections. Setting the Environment First set up the environment variables.  The variables highlighted in red probably need changing for your environment. #!/bin/sh echo "###########################" echo "# Setting SOA Environment #" echo "###########################" export MW_HOME=~oracle/Middleware11gPS1 export WL_HOME=$MW_HOME/wlserver_10.3 export ORACLE_HOME=$MW_HOME/Oracle_SOA export DOMAIN_NAME=soa_std_domain export DOMAIN_HOME=$MW_HOME/user_projects/domains/$DOMAIN_NAME Starting the Node Manager I start node manager with a nohup to stop it exiting when the script terminates and I redirect the standard output and standard error to a file in a logs directory. cd $DOMAIN_HOME echo "#########################" echo "# Starting Node Manager #" echo "#########################" nohup $WL_HOME/server/bin/startNodeManager.sh >logs/NodeManager.out 2>&1 & Starting the Admin Server I had problems starting the Admin Server from Node Manager so I decided to start it using the command line script.  I again use nohup and redirect output. echo "#########################" echo "# Starting Admin Server #" echo "#########################" nohup ./startWebLogic.sh >logs/AdminServer.out 2>&1 & Starting the Managed Servers I then used WLST (WebLogic Scripting Tool) to start the managed servers.  First I waited for the Admin Server to come up by putting a connect command in a loop.  I could have put the WLST commands into a separate script file but I wanted to reduce the number of files I was using and so used redirected input (here syntax). $ORACLE_HOME/common/bin/wlst.sh <<-EOF import time sleep=time.sleep print "#####################################" print "# Waiting for Admin Server to Start #" print "#####################################" while True:   try:     connect(adminServerName="AdminServer")     break   except:     sleep(10) I then start the SOA server and tell WLST to wait until it is started before returning.  If starting a cluster then the start command would be modified accordingly to start the SOA cluster. print "#######################" print "# Starting SOA Server #" print "#######################" start(name="soa_server1", block="true") I then start the BAM server in the same way as the SOA server. print "#######################" print "# Starting BAM Server #" print "#######################" start(name="bam_server1", block="true") EOF Finally I let people know the servers are up and wait for input in case I am running in a separate window, in which case the result would be lost without the read command. echo "#####################" echo "# SOA Suite Started #" echo "#####################" read -p "Hit <enter> to continue" Stopping the SOA Suite My script for shutting down the SOA Suite (available here)  is basically the reverse of my startup script.  After setting the environment I connect to the Admin Server using WLST and shut down the managed servers and the admin server.  Again the script would need modifying for a cluster. Stopping the Servers If I cannot connect to the Admin Server I try to connect to the node manager, in case the Admin Server is down but the managed servers are up. #!/bin/sh echo "###########################" echo "# Setting SOA Environment #" echo "###########################" export MW_HOME=~oracle/Middleware11gPS1 export WL_HOME=$MW_HOME/wlserver_10.3 export ORACLE_HOME=$MW_HOME/Oracle_SOA export DOMAIN_NAME=soa_std_domain export DOMAIN_HOME=$MW_HOME/user_projects/domains/$DOMAIN_NAME cd $DOMAIN_HOME $MW_HOME/Oracle_SOA/common/bin/wlst.sh <<-EOF try:   print("#############################")   print("# Connecting to AdminServer #")   print("#############################")   connect(username='weblogic',password='welcome1',url='t3://localhost:7001') except:   print "#########################################"   print "#   Unable to connect to Admin Server   #"   print "# Attempting to connect to Node Manager #"   print "#########################################"   nmConnect(domainName=os.getenv("DOMAIN_NAME")) print "#######################" print "# Stopping BAM Server #" print "#######################" shutdown('bam_server1') print "#######################" print "# Stopping SOA Server #" print "#######################" shutdown('soa_server1') print "#########################" print "# Stopping Admin Server #" print "#########################" shutdown('AdminServer') disconnect() nmDisconnect() EOF Stopping the Node Manager I stopped the node manager by searching for the java node manager process using the ps command and then killing that process. echo "#########################" echo "# Stopping Node Manager #" echo "#########################" kill -9 `ps -ef | grep java | grep NodeManager |  awk '{print $2;}'` echo "#####################" echo "# SOA Suite Stopped #" echo "#####################" read -p "Hit <enter> to continue" Stopping the Database Again my script for shutting down the database is the reverse of my start script.  It is available here.  The only change needed might be to the database name. #!/bin/sh echo "##############################" echo "# Setting Oracle Environment #" echo "##############################" . oraenv <<-EOF orcl EOF echo "######################" echo "# Stopping dbConsole #" echo "######################" emctl stop dbconsole echo "#####################" echo "# Stopping Listener #" echo "#####################" lsnrctl stop echo "#####################" echo "# Stopping Database #" echo "#####################" sqlplus / as sysdba <<-EOF shutdown immediate exit EOF read -p "Hit <enter> to continue" Cleaning Up Cleaning SOA Suite I often run tests and want to clean up all the log files.  The following script (available here) does this for the WebLogic servers in a given domain on a machine.  After setting the domain I just remove all files under the servers logs directories.  It also cleans up the log files I created with my startup scripts.  These scripts could be enhanced to copy off the log files if you needed them but in my test environments I don’t need them and would prefer to reclaim the disk space. #!/bin/sh echo "###########################" echo "# Setting SOA Environment #" echo "###########################" export MW_HOME=~oracle/Middleware11gPS1 export WL_HOME=$MW_HOME/wlserver_10.3 export ORACLE_HOME=$MW_HOME/Oracle_SOA export DOMAIN_NAME=soa_std_domain export DOMAIN_HOME=$MW_HOME/user_projects/domains/$DOMAIN_NAME echo "##########################" echo "# Cleaning SOA Log Files #" echo "##########################" cd $DOMAIN_HOME rm -Rf logs/* servers/*/logs/* read -p "Hit <enter> to continue" Cleaning Database I also created a script to clean up the dump files of an Oracle database instance and also the EM log files (available here).  This relies on the machine name being correct as the EM log files are stored in a directory that is based on the hostname and the Oracle SID. #!/bin/sh echo "##############################" echo "# Setting Oracle Environment #" echo "##############################" . oraenv <<-EOF orcl EOF echo "#############################" echo "# Cleaning Oracle Log Files #" echo "#############################" rm -Rf $ORACLE_BASE/admin/$ORACLE_SID/*dump/* rm -Rf $ORACLE_HOME/`hostname`_$ORACLE_SID/sysman/log/* read -p "Hit <enter> to continue" Summary Hope you find the above scripts useful.  They certainly stop me hanging around waiting for things to happen on my test machine and make it easy to run a test, change parameters, bounce the SOA Suite and clean the logs between runs so I can see exactly what is happening. Now I need to get that mower started…

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• SQL SERVER – LCK_M_XXX – Wait Type – Day 15 of 28

  - by pinaldave

  Locking is a mechanism used by the SQL Server Database Engine to synchronize access by multiple users to the same piece of data, at the same time. In simpler words, it maintains the integrity of data by protecting (or preventing) access to the database object. From Book On-Line: LCK_M_BU Occurs when a task is waiting to acquire a Bulk Update (BU) lock. LCK_M_IS Occurs when a task is waiting to acquire an Intent Shared (IS) lock. LCK_M_IU Occurs when a task is waiting to acquire an Intent Update (IU) lock. LCK_M_IX Occurs when a task is waiting to acquire an Intent Exclusive (IX) lock. LCK_M_S Occurs when a task is waiting to acquire a Shared lock. LCK_M_SCH_M Occurs when a task is waiting to acquire a Schema Modify lock. LCK_M_SCH_S Occurs when a task is waiting to acquire a Schema Share lock. LCK_M_SIU Occurs when a task is waiting to acquire a Shared With Intent Update lock. LCK_M_SIX Occurs when a task is waiting to acquire a Shared With Intent Exclusive lock. LCK_M_U Occurs when a task is waiting to acquire an Update lock. LCK_M_UIX Occurs when a task is waiting to acquire an Update With Intent Exclusive lock. LCK_M_X Occurs when a task is waiting to acquire an Exclusive lock. LCK_M_XXX Explanation: I think the explanation of this wait type is the simplest. When any task is waiting to acquire lock on any resource, this particular wait type occurs. The common reason for the task to be waiting to put lock on the resource is that the resource is already locked and some other operations may be going on within it. This wait also indicates that resources are not available or are occupied at the moment due to some reasons. There is a good chance that the waiting queries start to time out if this wait type is very high. Client application may degrade the performance as well. You can use various methods to find blocking queries: EXEC sp_who2 SQL SERVER – Quickest Way to Identify Blocking Query and Resolution – Dirty Solution DMV – sys.dm_tran_locks DMV – sys.dm_os_waiting_tasks Reducing LCK_M_XXX wait: Check the Explicit Transactions. If transactions are very long, this wait type can start building up because of other waiting transactions. Keep the transactions small. Serialization Isolation can build up this wait type. If that is an acceptable isolation for your business, this wait type may be natural. The default isolation of SQL Server is ‘Read Committed’. One of my clients has changed their isolation to “Read Uncommitted”. I strongly discourage the use of this because this will probably lead to having lots of dirty data in the database. Identify blocking queries mentioned using various methods described above, and then optimize them. Partition can be one of the options to consider because this will allow transactions to execute concurrently on different partitions. If there are runaway queries, use timeout. (Please discuss this solution with your database architect first as timeout can work against you). Check if there is no memory and IO-related issue using the following counters: Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Beginning of SQL Server Architecture – Terminology – Guest Post

  - by pinaldave

  SQL Server Architecture is a very deep subject. Covering it in a single post is an almost impossible task. However, this subject is very popular topic among beginners and advanced users.  I have requested my friend Anil Kumar who is expert in SQL Domain to help me write  a simple post about Beginning SQL Server Architecture. As stated earlier this subject is very deep subject and in this first article series he has covered basic terminologies. In future article he will explore the subject further down. Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. In this Article we will discuss about MS SQL Server architecture. The major components of SQL Server are: Relational Engine Storage Engine SQL OS Now we will discuss and understand each one of them. 1) Relational Engine: Also called as the query processor, Relational Engine includes the components of SQL Server that determine what your query exactly needs to do and the best way to do it. It manages the execution of queries as it requests data from the storage engine and processes the results returned. Different Tasks of Relational Engine: Query Processing Memory Management Thread and Task Management Buffer Management Distributed Query Processing 2) Storage Engine: Storage Engine is responsible for storage and retrieval of the data on to the storage system (Disk, SAN etc.). to understand more, let’s focus on the following diagram. When we talk about any database in SQL server, there are 2 types of files that are created at the disk level – Data file and Log file. Data file physically stores the data in data pages. Log files that are also known as write ahead logs, are used for storing transactions performed on the database. Let’s understand data file and log file in more details: Data File: Data File stores data in the form of Data Page (8KB) and these data pages are logically organized in extents. Extents: Extents are logical units in the database. They are a combination of 8 data pages i.e. 64 KB forms an extent. Extents can be of two types, Mixed and Uniform. Mixed extents hold different types of pages like index, System, Object data etc. On the other hand, Uniform extents are dedicated to only one type. Pages: As we should know what type of data pages can be stored in SQL Server, below mentioned are some of them: Data Page: It holds the data entered by the user but not the data which is of type text, ntext, nvarchar(max), varchar(max), varbinary(max), image and xml data. Index: It stores the index entries. Text/Image: It stores LOB ( Large Object data) like text, ntext, varchar(max), nvarchar(max),  varbinary(max), image and xml data. GAM & SGAM (Global Allocation Map & Shared Global Allocation Map): They are used for saving information related to the allocation of extents. PFS (Page Free Space): Information related to page allocation and unused space available on pages. IAM (Index Allocation Map): Information pertaining to extents that are used by a table or index per allocation unit. BCM (Bulk Changed Map): Keeps information about the extents changed in a Bulk Operation. DCM (Differential Change Map): This is the information of extents that have modified since the last BACKUP DATABASE statement as per allocation unit. Log File: It also known as write ahead log. It stores modification to the database (DML and DDL). Sufficient information is logged to be able to: Roll back transactions if requested Recover the database in case of failure Write Ahead Logging is used to create log entries Transaction logs are written in chronological order in a circular way Truncation policy for logs is based on the recovery model SQL OS: This lies between the host machine (Windows OS) and SQL Server. All the activities performed on database engine are taken care of by SQL OS. It is a highly configurable operating system with powerful API (application programming interface), enabling automatic locality and advanced parallelism. SQL OS provides various operating system services, such as memory management deals with buffer pool, log buffer and deadlock detection using the blocking and locking structure. Other services include exception handling, hosting for external components like Common Language Runtime, CLR etc. I guess this brief article gives you an idea about the various terminologies used related to SQL Server Architecture. In future articles we will explore them further. Guest Author  The author of the article is Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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• SQL SERVER – Index Created on View not Used Often – Observation of the View – Part 2

  - by pinaldave

  Earlier, I have written an article about SQL SERVER – Index Created on View not Used Often – Observation of the View. I received an email from one of the readers, asking if there would no problems when we create the Index on the base table. Well, we need to discuss this situation in two different cases. Before proceeding to the discussion, I strongly suggest you read my earlier articles. To avoid the duplication, I am not going to repeat the code and explanation over here. In all the earlier cases, I have explained in detail how Index created on the View is not utilized. SQL SERVER – Index Created on View not Used Often – Limitation of the View 12 SQL SERVER – Index Created on View not Used Often – Observation of the View SQL SERVER – Indexed View always Use Index on Table As per earlier blog posts, so far we have done the following: Create a Table Create a View Create Index On View Write SELECT with ORDER BY on View However, the blog reader who emailed me suggests the extension of the said logic, which is as follows: Create a Table Create a View Create Index On View Write SELECT with ORDER BY on View Create Index on the Base Table Write SELECT with ORDER BY on View After doing the last two steps, the question is “Will the query on the View utilize the Index on the View, or will it still use the Index of the base table?“ Let us first run the Create example. USE tempdb GO IF EXISTS (SELECT * FROM sys.views WHERE OBJECT_ID = OBJECT_ID(N'[dbo].[SampleView]')) DROP VIEW [dbo].[SampleView] GO IF EXISTS (SELECT * FROM sys.objects WHERE OBJECT_ID = OBJECT_ID(N'[dbo].[mySampleTable]') AND TYPE IN (N'U')) DROP TABLE [dbo].[mySampleTable] GO -- Create SampleTable CREATE TABLE mySampleTable (ID1 INT, ID2 INT, SomeData VARCHAR(100)) INSERT INTO mySampleTable (ID1,ID2,SomeData) SELECT TOP 100000 ROW_NUMBER() OVER (ORDER BY o1.name), ROW_NUMBER() OVER (ORDER BY o2.name), o2.name FROM sys.all_objects o1 CROSS JOIN sys.all_objects o2 GO -- Create View CREATE VIEW SampleView WITH SCHEMABINDING AS SELECT ID1,ID2,SomeData FROM dbo.mySampleTable GO -- Create Index on View CREATE UNIQUE CLUSTERED INDEX [IX_ViewSample] ON [dbo].[SampleView] ( ID2 ASC ) GO -- Select from view SELECT ID1,ID2,SomeData FROM SampleView ORDER BY ID2 GO -- Create Index on Original Table -- On Column ID1 CREATE UNIQUE CLUSTERED INDEX [IX_OriginalTable] ON mySampleTable ( ID1 ASC ) GO -- On Column ID2 CREATE UNIQUE NONCLUSTERED INDEX [IX_OriginalTable_ID2] ON mySampleTable ( ID2 ) GO -- Select from view SELECT ID1,ID2,SomeData FROM SampleView ORDER BY ID2 GO Now let us see the execution plans for both of the SELECT statement. Before Index on Base Table (with Index on View): After Index on Base Table (with Index on View): Looking at both executions, it is very clear that with or without, the View is using Indexes. Alright, I have written 11 disadvantages of the Views. Now I have written one case where the View is using Indexes. Anybody who says that I am being harsh on Views can say now that I found one place where Index on View can be helpful. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL View, SQLServer, T SQL, Technology

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