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  • How to configure background image to be at the bottom OpenGL Android

    - by Maxim Shoustin
    I have class that draws white line: public class Line { //private FloatBuffer vertexBuffer; private FloatBuffer frameVertices; ByteBuffer diagIndices; float[] vertices = { -0.5f, -0.5f, 0.0f, -0.5f, 0.5f, 0.0f }; public Line(GL10 gl) { // a float has 4 bytes so we allocate for each coordinate 4 bytes ByteBuffer vertexByteBuffer = ByteBuffer.allocateDirect(vertices.length * 4); vertexByteBuffer.order(ByteOrder.nativeOrder()); // allocates the memory from the byte buffer frameVertices = vertexByteBuffer.asFloatBuffer(); // fill the vertexBuffer with the vertices frameVertices.put(vertices); // set the cursor position to the beginning of the buffer frameVertices.position(0); } /** The draw method for the triangle with the GL context */ public void draw(GL10 gl) { gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glVertexPointer(2, GL10.GL_FLOAT, 0, frameVertices); gl.glColor4f(1.0f, 1.0f, 1.0f, 1f); gl.glDrawArrays(GL10.GL_LINE_LOOP , 0, vertices.length / 3); gl.glLineWidth(5.0f); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); } } It works fine. The problem is: When I add BG image, I don't see the line glView = new GLSurfaceView(this); // Allocate a GLSurfaceView glView.setEGLConfigChooser(8, 8, 8, 8, 16, 0); glView.setRenderer(new mainRenderer(this)); // Use a custom renderer glView.setBackgroundResource(R.drawable.bg_day); // <- BG glView.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY); glView.getHolder().setFormat(PixelFormat.TRANSLUCENT); How to get rid of that?

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  • What does the ".align" x86 Assembler directive do exactly? [migrated]

    - by Sinister Clock
    I will list exactly what I do not understand, and show you the parts I can not understand as well. First off, The .Align Directive .align integer, pad. The .align directive causes the next data generated to be aligned modulo integer bytes 1.~ ? : What is implied with "causes the next data generated to be aligned modulo integer bytes?" I can surmise that the next data generated is a memory-to-register transfer, no? Modulo would imply the remainder of a division. I do not understand "to be aligned modulo integer bytes"....... What would be a remainder of a simple data declaration, and how would the next data generated being aligned by a remainder be useful? If the next data is aligned modulo, that is saying the next generated data, whatever that means exactly, is the remainder of an integer? That makes absolutely no sense. What specifically would the .align, say, .align 8 directive issued in x86 for a data byte compiled from a C char, i.e., char CHARACTER = 0; be for? Or specifically coded directly with that directive, not preliminary Assembly code after compiling C? I have debugged in Assembly and noticed that any C/C++ data declarations, like chars, ints, floats, etc. will insert the directive .align 8 to each of them, and add other directives like .bss, .zero, .globl, .text, .Letext0, .Ltext0. What are all of these directives for, or at least my main asking? I have learned a lot of the main x86 Assembly instructions, but never was introduced or pointed at all of these strange directives. How do they affect the opcodes, and are all of them necessary?

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  • Information I need to know as a Java Developer [on hold]

    - by Woy
    I'm a java developer. I'm trying to get more knowledge to become a better programmer. I've listed a number of technologies to learn. Instead of what I've listed, what technologies would you suggest to learn as well for a Junior Java Developer? I realize, there's a lot of things to study. Java: - how a garbage collector works - resource management - network programming - TCP/IP HTTP - transactions, - consistency: interfaces, classes collections, hash codes, algorithms, comp. complexity concurrent programming: synchronizing, semafores steam management metability: thread-safety byte code manipulations, reflections, Aspect-Oriented Programming as base to understand frameworks such as Spring etc. Web stack: servlets, filters, socket programming Libraries: JDK, GWT, Apache Commons, Joda-Time, Dependency Injections: Spring, Nano Tools: IDE: very good knowledge - debugger - profiler - web analyzers: Wireshark, firebugs - unit testing SQL/Databases: Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING + Intermediate JOINs, ANSI-89 and ANSI-92 syntax + UNION vs UNION ALL x NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated ITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic SQL Materialized Views Query Optimization: Indexes Query Optimization: Explain Plans Query Optimization: Profiling Data Modelling: Normal Forms, 1 through 3 Data Modelling: Primary & Foreign Keys Data Modelling: Table Constraints Data Modelling: Link/Corrollary Tables Full Text Searching XML Isolation Levels Entity Relationship Diagrams (ERDs), Logical and Physical Transactions: COMMIT, ROLLBACK, Error Handling

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  • Storing large array of tiles, but allowing easy access to data

    - by Cyral
    I've been thinking about this for a while. I have a 2D tile bases platformer in XNA with a large array of tile data, I've been running into memory problems with large maps. (I will add chunks soon!) Currently, Each tile contains an Item along with other properties like how its rotated, if it has forground / background, etc. An Item is static and has properties like the name, tooltip, type of item, how much light it emits, the collision it does to player, etc. Examples: public class Item { public static List<Item> Items; public Collision blockCollisionType; public string nameOfItem; public bool someOtherVariable,etc,etc public static Item Air public static Item Stone; public static Item Dirt; static Item() { Items = new List<Item>() { (Stone = new Item() { nameOfItem = "Stone", blockCollisionType = Collision.Solid, }), (Air = new Item() { nameOfItem = "Air", blockCollisionType = Collision.Passable, }), }; } } Would be an Item, The array of Tiles would contain a Tile for each point, public class Tile { public Item item; //What type it is public bool onBackground; public int someOtherVariables,etc,etc } Now, Most would probably use an enum, or a form of ID to identify blocks. Well my system is really nice just to find out about an item. I can simply do tiles[x,y].item.Name To get the name for example. I realized my Item property of the tile is over 1000 Bytes! Wow! What I'm looking for is a way to use an ID (Int or byte depending on how many items) instead of an Item but still have a method for retreiving data about the type of item a tile contains.

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  • Any good reason to open files in text mode?

    - by Tinctorius
    (Almost-)POSIX-compliant operating systems and Windows are known to distinguish between 'binary mode' and 'text mode' file I/O. While the former mode doesn't transform any data between the actual file or stream and the application, the latter 'translates' the contents to some standard format in a platform-specific manner: line endings are transparently translated to '\n' in C, and some platforms (CP/M, DOS and Windows) cut off a file when a byte with value 0x1A is found. These transformations seem a little useless to me. People share files between computers with different operating systems. Text mode would cause some data to be handled differently across some platforms, so when this matters, one would probably use binary mode instead. As an example: while Windows uses the sequence CR LF to end a line in text mode, UNIX text mode will not treat CR as part of the line ending sequence. Applications would have to filter that noise themselves. Older Mac versions only use CR in text mode as line endings, so neither UNIX nor Windows would understand its files. If this matters, a portable application would probably implement the parsing by itself instead of using text mode. Implementing newline interpretation in the parser might also remove some overhead of using text mode, as buffers would need to be rewritten (and possibly resized) before returning to the application, while this may be less efficient than when it would happen in the application instead. So, my question is: is there any good reason to still rely on the host OS to translate line endings and file truncation?

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  • How do you go from a so so programmer to a great one? [closed]

    - by Cervo
    How do you go from being an okay programmer to being able to write maintainable clean code? For example David Hansson was writing Basecamp when in the process he created Rails as part of writing Basecamp in a clean/maintainable way. But how do you know when there is value in a side project like that? I have a bachelors in computer science, and I am about to get a masters and I will say that colleges teach you to write code to solve problems, not neatly or anything. Basically you think of a problem, come up with a solution, and write it down...not necessarily the most maintainable way in the world. Also my first job was in a startup, and now my third is in a small team in a large company where the attitude was/is get it done yesterday (also most of my jobs are mainly database development with SQL with a few ASP.NET web pages/.NET apps on the side). So of course cut/paste is more favored than making things more cleanly. And they would rather have something yesterday even if you have to rewrite it next month rather than to have something in a week that lasts for a year. Also spaghetti code turns up all over the place, and it takes very smart people to write/understand/maintain spaghetti code...However it would be better to do things so simple/clean that even a caveman/woman could do maintenance. Also I get very bored/unmotivated having to go modify the same things cut/pasted in a few locations. Is this the type of skill that you need to learn by working with a serious software organization that has an emphasis on maintenance and maybe even an architect who designs a system architecture and reviews code? Could you really learn it by volunteering on an open source project (it seems to me that a full time programmer job is way more practice than a few hours a week on an open source project)? Is there some course where you can learn this? I can attest that graduate school and undergraduate school do not really emphasize clean software at all. They just teach the structures/algorithms and then send you off into the world to solve problems. Overall I think the first thing is learning to write clean/maintainable code within the bounds of the project in order to become a good programmer. Then the next thing is learning when you need to do a side project (like a framework) to make things more maintainable/clean even while you still deliver things for the deadline in order to become a great programmer. For example, you are making an SQL report and someone gives you 100 calculations for individual columns. At what point does it make sense to construct a domain specific language to encode the rules in simply and then generate all the SQL as opposed to cut/pasting the query from the table a bunch of times and then adjusting each query to do the appropriate calculations. This is the type of thing I would say a great programmer would know. He/she would maybe even know ways to avoid the domain specific language and to still do all the calculations without creating an unmaintainable mess or a ton of repetitive code to cut/paste everywhere.

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  • Help with Abstract Factory Pattern

    - by brazc0re
    I need help with a abstract factory pattern design. This question is a continuation of: Design help with parallel process I am really confused where I should be initializing all of the settings for each type of medium (ex: RS232, TCP/IP, etc). Attached is the drawing on how I am setting up the pattern: As shown, when a medium is created, each medium imposes a ICreateMedium interface. I would assume that the Create() method also create the proper object, such as SerialPort serialPort = new SerialPort("COM1", baud); however, TCPIPMedium would have an issue with the interface because it wouldn't need to initialize a serial port object. I know I am doing something majorly wrong here. I just can't figure it out and have been stuck for a while. What I also get confused on show the interface IMedium will get access to the communication object once it is created so it can write out the appropriate byte[] packet. Any guidance would be greatly appreciated. My main goal is to have the Communicator class spit a packet out without caring which type of medium is active.

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  • Appcache and jquery mobile on a CMS powered site?

    - by user793011
    Has anyone used the cache manifest to make a CMS site work offline? I've made a demo with static html files which seems to work fine, so I'm assuming it wouldn't be too hard to achieve the same thing with a CMS. The way that you tell browsers that files have changed (and so need to be downloaded again) is by adding a comment to the cache manifest file so its byte size changes. I'm not quite sure how to do this with a CMS, but maybe some sort of server cron could run periodically? Personally I'm more interested in having a site that works offline rather than achieving ideal performance, so if the file was modified every hour rather than when content actually changed that would be fine for me. If anyone has used appcache with a CMS, has anyone done so with jquery mobile at the same time? What I'm after is a fully native feel to a site that's accessible offline, in other words I want to mimic a native App. My static demo does this perfectly with jquery mobile, so again I would have thought this would be achievable in a CMS.

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  • Is this too much to ask for a game programming and developing enthusiast? Am I doing this wrong?

    - by I_Question_Things_Deeply
    I have been a computer-fanatic for almost a decade now. I've always loved and wondered how computers work, even from the purest, lowest hardware level to the very smallest pixel on the screen, and all the software around that. That seems to be my problem though ... as I try to write code (I'm pretty fluent at C++) I always sit there enormous amounts of time in front of a text-editor wondering how every line, statement, datum, function, etc. will correspond to every Assembly and machine instruction performed to do absolutely everything necessary for the kernel to allocate memory to run my compiled program, and all of the other hardware being used as well. For example ... I would write cout << "Before memory changed" << endl; and run the debugger to get the Assembly for this, and then try and reverse disassemble the Assembly to machine code based on my ISA, and then research every .dll, library file, linked library, linking process, linker source code of the program, the make file, the kernel I'm using's steps of processing this compilation, the hardware's part aside from the processor (e.g. video card, sound card, chipset, cache latency, byte-sized registers, calling convention use, DDR3 RAM and disk drive, filesystem functioning and so many other things). Am I going about programming wrong? I mean I feel I should know everything that goes on underneath English syntax on a computer program. But the problem is that the more I research every little thing the less I actually accomplish at all. I can never finish anything because of this mentality, yet I feel compelled to know everything... what should I do?

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  • Strings are UTF-16&hellip;. There is an error in XML document (1, 1).

    - by Shawn Cicoria
    I had a situation today where an xml document had a directive indicating it was utf-8.  So, the code in question was reading in the “string” of that xml then attempting to de-serialize it using an Xsd generated type. What you end up with is an exception indicating that there’s an error in the Xml document at (1,1) or something to that effect. The fix is, run it through a memory stream – which reads the string, but at utf8 bytes – if you have things that fall outside of 8 bit chars, you’ll get an exception.   //Need to read it to bytes, to undo the fact that strings are UTF-16 all the time. //We want it to handle it as UTF8. byte[] bytes = Encoding.UTF8.GetBytes(_myXmlString); TargetType myInstance = null; using (MemoryStream memStream = new MemoryStream(bytes)) { XmlSerializer tokenSerializer = new XmlSerializer(typeof(TargetType)); myInstance = (TargetType)tokenSerializer.Deserialize(memStream); }   Writing is similar – also, adding the default namespace prevents the additional xmlns additions that aren’t necessary:   XmlWriterSettings settings = new XmlWriterSettings() { Encoding = Encoding.UTF8, Indent = true, NewLineOnAttributes = true, }; XmlSerializerNamespaces xmlnsEmpty = new XmlSerializerNamespaces(); xmlnsEmpty.Add("", "http://www.wow.thisworks.com/2010/05"); MemoryStream memStr = new MemoryStream(); using (XmlWriter writer = XmlTextWriter.Create(memStr, settings)) { XmlSerializer tokenSerializer = new XmlSerializer(typeof(TargetType)); tokenSerializer.Serialize(writer, theInstance, xmlnsEmpty); }

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  • Any faster method?

    - by rajeshverma423
    Manhattan distance is used to the center in chess code that uses an 0x88 board . 0x88 board is 128 square. public static final byte DISTANCE[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 5, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 5, 4, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 7, 6, 5, 4, 3, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 0, 0, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 7, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 7, 6, 5, 4, 3, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 7, 6, 5, 4, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 5, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; Is there any other faster method instead of 0x88 to find distance?

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  • How can I change the color of the text in my iFrame? [closed]

    - by VinylScratch
    I have code here: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>Frag United Banlist</title> </head> <body> <h1>Tekkit Banlist</h1> <?php // change these things $server = "server-host"; $dbuser = "correct-user"; $dbpass = "correct-password"; $dbname = "correct-database"; mysql_connect($server, $dbuser, $dbpass); mysql_select_db($dbname); $result = mysql_query("SELECT * FROM banlist ORDER BY id DESC"); //This will display the most recent by id edit this query how you see fit. Limit, Order, ect. echo "<table width=100% border=1 cellpadding=3 cellspacing=0>"; echo "<tr style=\"font-weight:bold\"> <td>ID</td> <td>User</td> <td>Reason</td> <td>Admin/Mod</td> <td>Time</td> <td>Ban Length</td> </tr>"; while($row = mysql_fetch_assoc($result)){ if($col == "#eeeeee"){ $col = "#ffffff"; }else{ $col = "#eeeeee"; } echo "<tr bgcolor=$col>"; echo "<td>".$row['id']."</td>"; echo "<td>".$row['user']."</td>"; echo "<td>".$row['reason']."</td>"; echo "<td>".$row['admin']."</td>"; //Convert Epoch Time to Standard format $datetime = date("F j, Y, g:i a", $row['time']); echo "<td>$datetime</td>"; $dateconvert = date("F j, Y, g:i a", $row['length']); if($row['length'] == "0"){ echo "<td>None</td>"; }else{ echo "<td>$dateconvert</td>"; } echo "<td>".$row['id']."</td>"; echo "</tr>"; } echo"</table>" ?> </div> </body></html> And I am trying to make it so that when I put it in this iframe: <iframe src="http://bans.fragunited.net/" width="100%" length="100%"><p>Your browser does not support iframes.</p></iframe> But if you go to this page, fragunited.net/bans, (not bans.fragunited.net) the text is black and I want it to be white so you can actually see it. Sorry for the large amount of code, however I don't know where you have to put the code to change the color.

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  • ?????????OutOfMemory?????????????????|WebLogic Channel|??????

    - by ???02
    WebLogic Server Enterprise Edition????????????JRockit Mission Control????????????????????????????????????????????????????????????????????????????????Application Grid???????? ????????????????? ???(?????? Fusion Middleware?????? ???????????)??????????????????JRockit Mission Control?????2?????(???)????????????OutOfMemory???????? Java????????????????????1????????????????????????OutOfMemory?????????????·??????JVM????????????????????????????????????????????????B?????OutOfMemory???????????? B????????????????·?????????????????????????WebLogic Server???????????????OutOfMemory??????????????????????????????????????????????????????????????????????????????????????????????????????? ????B???????????????JRockit Mission Control?1??????Memory Leak Detector?????OutOfMemory???????????????Memory Leak Detector?Java????????????·??????????????????????????????????????????????????????????????????????????????????????????????????????? Memory Leak Detector?????????????????????????????????????(byte[])???????????????????????????????????·??????(GC)???????????????????????????????? ????????????????????????????????????????????????Memory Leak Detector????·??????????·??????????????????????????????????????????????????????????????ThreadLocal??????????????????????????40%??????????????????java.lang.ThreadLocal????????? WebLogic Server???Java EE????????·????????????????/??????????????????????????????????????·???????????????????????·????ThreadLocal?????????????·???????????????????????·?????????????????ThreadLocal???????????????????????????ThreadLocal?????????????????????????????? ???????ThreadLocal?????????????????Memory Leak Detector?????????????????????·?????????????????????????????(ThreadLocal???????????????)???????·????????????????????????????????????????????????????????????1????????????1?????·????????????????????????????????????????????·???????????????? ??B???????WebLogic Server???????????????????????????????WebLogic Server????2???????????????????????????????????????????????????????????????????1?????????????2?????·?????????????2?????????·??????????? ???ThreadLocal???????????????ThreadLocal????????????????Thread??????????????????????????????????????Thread???????????????????GC?????????????????GC????????????????????????·?????????????????????????????????????????????·?????????????????????????????(????????·???·???·????)? WebLogic Server???????????????????????????????????????????????(?????????????????)???"????"?????????????????????????????GC??????????ThreadLocal???????????????????????????????????????GC?????????????????????????????????????????????????????????????????????????????????OutOfMemory????????????????? ??????????????????JRockit Flight Recorder?JRockit Mission Control????????????????????????????????????ThreadLocal????????????????????????????·???·????????????????????????????JRockit Flight Recorder/JRockit Mission Control????????WebLogic Server?????????????????????????????????·???????????????? ????????????????????????????·???????????C??????????WebLogic Server??????????????????????????????????????????????4??(1????×4??)??????12??(2????×6??)??????????? ??????????3?????????????????????????????????????????????????4??·???????3,500??????????????12??????????2,000??????????????????? ???C??????????JVM????·????GC?????????????????????????OS???????????·?????????????????????????????????????????????? ???????????????????????JRockit Flight Recorder?????????????????????????????????????·?????????????????30?????????????????????? ???????????????????1?????????????????????(??????·?????)?????????????????????WebLogic Server??????????????????????????????????????????·????????????????????? ???????????????????????????????????????????????????????Spin(???)??????????????????·???????????????????????????????????????????????????????????·???????????????JRockit Flight Recorder??????????????????12??????????????·??????????????????(4??/1 JVM)????Java???·????????????(12??/1 JVM)????Java???·???????? ??????·?????????CPU????????????????????????????·???????????????????????????????CPU??????????????????????????????????????????????????????·?????????????????????????????·???? ?????????·??????????????????·????????????????????????????????????????????????????????????·??????????????????????????????????·?????????????????????·?????????????????(?????????????·???????????????????)? WebLogic Server?JVM???Oracle JRockit???CPU???????JVM?????????????JVM?????????????????????????????????????????????????(JVM????-XX:BindToCPUs???????????CPU?????????JVM???-XX:NumaMemoryPolicy=strictlocal???????????????·?????????)??????????·???????????????????????????????(12??/1 JVM)????Java???·????????(?????)*   *   * ??????????3?????????????????????????????????????????????????WebLogic Server????OS?????????????????????????????????JRockit Flight Recorder??????????????JRockit Mission Control???????????????????????????????????????????WebLogic Server?????????????????????????????????????JRockit Flight Recorder /JRockit Mission Control??????????????????????????????????????????????????????????????????????????????????????

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  • Use IIS Application Initialization for keeping ASP.NET Apps alive

    - by Rick Strahl
    I've been working quite a bit with Windows Services in the recent months, and well, it turns out that Windows Services are quite a bear to debug, deploy, update and maintain. The process of getting services set up,  debugged and updated is a major chore that has to be extensively documented and or automated specifically. On most projects when a service is built, people end up scrambling for the right 'process' to use for administration. Web app deployment and maintenance on the other hand are common and well understood today, as we are constantly dealing with Web apps. There's plenty of infrastructure and tooling built into Web Tools like Visual Studio to facilitate the process. By comparison Windows Services or anything self-hosted for that matter seems convoluted.In fact, in a recent blog post I mentioned that on a recent project I'd been using self-hosting for SignalR inside of a Windows service, because the application is in fact a 'service' that also needs to send out lots of messages via SignalR. But the reality is that it could just as well be an IIS application with a service component that runs in the background. Either way you look at it, it's either a Windows Service with a built in Web Server, or an IIS application running a Service application, neither of which follows the standard Service or Web App template.Personally I much prefer Web applications. Running inside of IIS I get all the benefits of the IIS platform including service lifetime management (crash and restart), controlled shutdowns, the whole security infrastructure including easy certificate support, hot-swapping of code and the the ability to publish directly to IIS from within Visual Studio with ease.Because of these benefits we set out to move from the self hosted service into an ASP.NET Web app instead.The Missing Link for ASP.NET as a Service: Auto-LoadingI've had moments in the past where I wanted to run a 'service like' application in ASP.NET because when you think about it, it's so much easier to control a Web application remotely. Services are locked into start/stop operations, but if you host inside of a Web app you can write your own ticket and control it from anywhere. In fact nearly 10 years ago I built a background scheduling application that ran inside of ASP.NET and it worked great and it's still running doing its job today.The tricky part for running an app as a service inside of IIS then and now, is how to get IIS and ASP.NET launched so your 'service' stays alive even after an Application Pool reset. 7 years ago I faked it by using a web monitor (my own West Wind Web Monitor app) I was running anyway to monitor my various web sites for uptime, and having the monitor ping my 'service' every 20 seconds to effectively keep ASP.NET alive or fire it back up after a reload. I used a simple scheduler class that also includes some logic for 'self-reloading'. Hacky for sure, but it worked reliably.Luckily today it's much easier and more integrated to get IIS to launch ASP.NET as soon as an Application Pool is started by using the Application Initialization Module. The Application Initialization Module basically allows you to turn on Preloading on the Application Pool and the Site/IIS App, which essentially fires a request through the IIS pipeline as soon as the Application Pool has been launched. This means that effectively your ASP.NET app becomes active immediately, Application_Start is fired making sure your app stays up and running at all times. All the other features like Application Pool recycling and auto-shutdown after idle time still work, but IIS will then always immediately re-launch the application.Getting started with Application InitializationAs of IIS 8 Application Initialization is part of the IIS feature set. For IIS 7 and 7.5 there's a separate download available via Web Platform Installer. Using IIS 8 Application Initialization is an optional install component in Windows or the Windows Server Role Manager: This is an optional component so make sure you explicitly select it.IIS Configuration for Application InitializationInitialization needs to be applied on the Application Pool as well as the IIS Application level. As of IIS 8 these settings can be made through the IIS Administration console.Start with the Application Pool:Here you need to set both the Start Automatically which is always set, and the StartMode which should be set to AlwaysRunning. Both have to be set - the Start Automatically flag is set true by default and controls the starting of the application pool itself while Always Running flag is required in order to launch the application. Without the latter flag set the site settings have no effect.Now on the Site/Application level you can specify whether the site should pre load: Set the Preload Enabled flag to true.At this point ASP.NET apps should auto-load. This is all that's needed to pre-load the site if all you want is to get your site launched automatically.If you want a little more control over the load process you can add a few more settings to your web.config file that allow you to show a static page while the App is starting up. This can be useful if startup is really slow, so rather than displaying blank screen while the user is fiddling their thumbs you can display a static HTML page instead: <system.webServer> <applicationInitialization remapManagedRequestsTo="Startup.htm" skipManagedModules="true"> <add initializationPage="ping.ashx" /> </applicationInitialization> </system.webServer>This allows you to specify a page to execute in a dry run. IIS basically fakes request and pushes it directly into the IIS pipeline without hitting the network. You specify a page and IIS will fake a request to that page in this case ping.ashx which just returns a simple OK string - ie. a fast pipeline request. This request is run immediately after Application Pool restart, and while this request is running and your app is warming up, IIS can display an alternate static page - Startup.htm above. So instead of showing users an empty loading page when clicking a link on your site you can optionally show some sort of static status page that says, "we'll be right back".  I'm not sure if that's such a brilliant idea since this can be pretty disruptive in some cases. Personally I think I prefer letting people wait, but at least get the response they were supposed to get back rather than a random page. But it's there if you need it.Note that the web.config stuff is optional. If you don't provide it IIS hits the default site link (/) and even if there's no matching request at the end of that request it'll still fire the request through the IIS pipeline. Ideally though you want to make sure that an ASP.NET endpoint is hit either with your default page, or by specify the initializationPage to ensure ASP.NET actually gets hit since it's possible for IIS fire unmanaged requests only for static pages (depending how your pipeline is configured).What about AppDomain Restarts?In addition to full Worker Process recycles at the IIS level, ASP.NET also has to deal with AppDomain shutdowns which can occur for a variety of reasons:Files are updated in the BIN folderWeb Deploy to your siteweb.config is changedHard application crashThese operations don't cause the worker process to restart, but they do cause ASP.NET to unload the current AppDomain and start up a new one. Because the features above only apply to Application Pool restarts, AppDomain restarts could also cause your 'ASP.NET service' to stop processing in the background.In order to keep the app running on AppDomain recycles, you can resort to a simple ping in the Application_End event:protected void Application_End() { var client = new WebClient(); var url = App.AdminConfiguration.MonitorHostUrl + "ping.aspx"; client.DownloadString(url); Trace.WriteLine("Application Shut Down Ping: " + url); }which fires any ASP.NET url to the current site at the very end of the pipeline shutdown which in turn ensures that the site immediately starts back up.Manual Configuration in ApplicationHost.configThe above UI corresponds to the following ApplicationHost.config settings. If you're using IIS 7, there's no UI for these flags so you'll have to manually edit them.When you install the Application Initialization component into IIS it should auto-configure the module into ApplicationHost.config. Unfortunately for me, with Mr. Murphy in his best form for me, the module registration did not occur and I had to manually add it.<globalModules> <add name="ApplicationInitializationModule" image="%windir%\System32\inetsrv\warmup.dll" /> </globalModules>Most likely you won't need ever need to add this, but if things are not working it's worth to check if the module is actually registered.Next you need to configure the ApplicationPool and the Web site. The following are the two relevant entries in ApplicationHost.config.<system.applicationHost> <applicationPools> <add name="West Wind West Wind Web Connection" autoStart="true" startMode="AlwaysRunning" managedRuntimeVersion="v4.0" managedPipelineMode="Integrated"> <processModel identityType="LocalSystem" setProfileEnvironment="true" /> </add> </applicationPools> <sites> <site name="Default Web Site" id="1"> <application path="/MPress.Workflow.WebQueueMessageManager" applicationPool="West Wind West Wind Web Connection" preloadEnabled="true"> <virtualDirectory path="/" physicalPath="C:\Clients\…" /> </application> </site> </sites> </system.applicationHost>On the Application Pool make sure to set the autoStart and startMode flags to true and AlwaysRunning respectively. On the site make sure to set the preloadEnabled flag to true.And that's all you should need. You can still set the web.config settings described above as well.ASP.NET as a Service?In the particular application I'm working on currently, we have a queue manager that runs as standalone service that polls a database queue and picks out jobs and processes them on several threads. The service can spin up any number of threads and keep these threads alive in the background while IIS is running doing its own thing. These threads are newly created threads, so they sit completely outside of the IIS thread pool. In order for this service to work all it needs is a long running reference that keeps it alive for the life time of the application.In this particular app there are two components that run in the background on their own threads: A scheduler that runs various scheduled tasks and handles things like picking up emails to send out outside of IIS's scope and the QueueManager. Here's what this looks like in global.asax:public class Global : System.Web.HttpApplication { private static ApplicationScheduler scheduler; private static ServiceLauncher launcher; protected void Application_Start(object sender, EventArgs e) { // Pings the service and ensures it stays alive scheduler = new ApplicationScheduler() { CheckFrequency = 600000 }; scheduler.Start(); launcher = new ServiceLauncher(); launcher.Start(); // register so shutdown is controlled HostingEnvironment.RegisterObject(launcher); }}By keeping these objects around as static instances that are set only once on startup, they survive the lifetime of the application. The code in these classes is essentially unchanged from the Windows Service code except that I could remove the various overrides required for the Windows Service interface (OnStart,OnStop,OnResume etc.). Otherwise the behavior and operation is very similar.In this application ASP.NET serves two purposes: It acts as the host for SignalR and provides the administration interface which allows remote management of the 'service'. I can start and stop the service remotely by shutting down the ApplicationScheduler very easily. I can also very easily feed stats from the queue out directly via a couple of Web requests or (as we do now) through the SignalR service.Registering a Background Object with ASP.NETNotice also the use of the HostingEnvironment.RegisterObject(). This function registers an object with ASP.NET to let it know that it's a background task that should be notified if the AppDomain shuts down. RegisterObject() requires an interface with a Stop() method that's fired and allows your code to respond to a shutdown request. Here's what the IRegisteredObject::Stop() method looks like on the launcher:public void Stop(bool immediate = false) { LogManager.Current.LogInfo("QueueManager Controller Stopped."); Controller.StopProcessing(); Controller.Dispose(); Thread.Sleep(1500); // give background threads some time HostingEnvironment.UnregisterObject(this); }Implementing IRegisterObject should help with reliability on AppDomain shutdowns. Thanks to Justin Van Patten for pointing this out to me on Twitter.RegisterObject() is not required but I would highly recommend implementing it on whatever object controls your background processing to all clean shutdowns when the AppDomain shuts down.Testing it outI'm still in the testing phase with this particular service to see if there are any side effects. But so far it doesn't look like it. With about 50 lines of code I was able to replace the Windows service startup to Web start up - everything else just worked as is. An honorable mention goes to SignalR 2.0's oWin hosting, because with the new oWin based hosting no code changes at all were required, merely a couple of configuration file settings and an assembly directive needed, to point at the SignalR startup class. Sweet!It also seems like SignalR is noticeably faster running inside of IIS compared to self-host. Startup feels faster because of the preload.Starting and Stopping the 'Service'Because the application is running as a Web Server, it's easy to have a Web interface for starting and stopping the services running inside of the service. For our queue manager the SignalR service and front monitoring app has a play and stop button for toggling the queue.If you want more administrative control and have it work more like a Windows Service you can also stop the application pool explicitly from the command line which would be equivalent to stopping and restarting a service.To start and stop from the command line you can use the IIS appCmd tool. To stop:> %windir%\system32\inetsrv\appcmd stop apppool /apppool.name:"Weblog"and to start> %windir%\system32\inetsrv\appcmd start apppool /apppool.name:"Weblog"Note that when you explicitly force the AppPool to stop running either in the UI (on the ApplicationPools page use Start/Stop) or via command line tools, the application pool will not auto-restart immediately. You have to manually start it back up.What's not to like?There are certainly a lot of benefits to running a background service in IIS, but… ASP.NET applications do have more overhead in terms of memory footprint and startup time is a little slower, but generally for server applications this is not a big deal. If the application is stable the service should fire up and stay running indefinitely. A lot of times this kind of service interface can simply be attached to an existing Web application, or if scalability requires be offloaded to its own Web server.Easier to work withBut the ultimate benefit here is that it's much easier to work with a Web app as opposed to a service. While developing I can simply turn off the auto-launch features and launch the service on demand through IIS simply by hitting a page on the site. If I want to shut down an IISRESET -stop will shut down the service easily enough. I can then attach a debugger anywhere I want and this works like any other ASP.NET application. Yes you end up on a background thread for debugging but Visual Studio handles that just fine and if you stay on a single thread this is no different than debugging any other code.SummaryUsing ASP.NET to run background service operations is probably not a super common scenario, but it probably should be something that is considered carefully when building services. Many applications have service like features and with the auto-start functionality of the Application Initialization module, it's easy to build this functionality into ASP.NET. Especially when combined with the notification features of SignalR it becomes very, very easy to create rich services that can also communicate their status easily to the outside world.Whether it's existing applications that need some background processing for scheduling related tasks, or whether you just create a separate site altogether just to host your service it's easy to do and you can leverage the same tool chain you're already using for other Web projects. If you have lots of service projects it's worth considering… give it some thought…© Rick Strahl, West Wind Technologies, 2005-2013Posted in ASP.NET  SignalR  IIS   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Q1 2010 New Feature: Paging with RadGridView for Silverlight and WPF

    We are glad to announce that the Q1 2010 Release has added another weapon to RadGridViews growing arsenal of features. This is the brand new RadDataPager control which provides the user interface for paging through a collection of data. The good news is that RadDataPager can be used to page any collection. It does not depend on RadGridView in any way, so you will be free to use it with the rest of your ItemsControls if you chose to do so. Before you read on, you might want to download the samples solution that I have attached. It contains a sample project for every scenario that I will discuss later on. Looking at the code while reading will make things much easier for you. There is something for everyone among the 10 Visual Studio projects that are included in the solution. So go and grab it. I. Paging essentials The single most important piece of software concerning paging in Silverlight is the System.ComponentModel.IPagedCollectionView interface. Those of you who are on the WPF front need not worry though. As you might already know, Teleriks Silverlight and WPF controls is share the same code-base. Since WPF does not contain a similar interface, Telerik has provided its own Telerik.Windows.Data.IPagedCollectionView. The IPagedCollectionView interface contains several important members which are used by RadGridView to perform the actual paging. Silverlight provides a default implementation of this interface which, naturally, is called PagedCollectionView. You should definitely take a look at its source code in case you are interested in what is going on under the hood. But this is not a prerequisite for our discussion. The WPF default implementation of the interface is Teleriks QueryableCollectionView which, among many other interfaces, implements IPagedCollectionView. II. No Paging In order to gradually build up my case, I will start with a very simple example that lacks paging whatsoever. It might sound stupid, but this will help us build on top of this paging-devoid example. Let us imagine that we have the simplest possible scenario. That is a simple IEnumerable and an ItemsControl that shows its contents. This will look like this: No Paging IEnumerable itemsSource = Enumerable.Range(0, 1000); this.itemsControl.ItemsSource = itemsSource; XAML <Border Grid.Row="0" BorderBrush="Black" BorderThickness="1" Margin="5">     <ListBox Name="itemsControl"/> </Border> <Border Grid.Row="1" BorderBrush="Black" BorderThickness="1" Margin="5">     <TextBlock Text="No Paging"/> </Border> Nothing special for now. Just some data displayed in a ListBox. The two sample projects in the solution that I have attached are: NoPaging_WPF NoPaging_SL3 With every next sample those two project will evolve in some way or another. III. Paging simple collections The single most important property of RadDataPager is its Source property. This is where you pass in your collection of data for paging. More often than not your collection will not be an IPagedCollectionView. It will either be a simple List<T>, or an ObservableCollection<T>, or anything that is simply IEnumerable. Unless you had paging in mind when you designed your project, it is almost certain that your data source will not be pageable out of the box. So what are the options? III. 1. Wrapping the simple collection in an IPagedCollectionView If you look at the constructors of PagedCollectionView and QueryableCollectionView you will notice that you can pass in a simple IEnumerable as a parameter. Those two classes will wrap it and provide paging capabilities over your original data. In fact, this is what RadGridView does internally. It wraps your original collection in an QueryableCollectionView in order to easily perform many useful tasks such as filtering, sorting, and others, but in our case the most important one is paging. So let us start our series of examples with the most simplistic one. Imagine that you have a simple IEnumerable which is the source for an ItemsControl. Here is how to wrap it in order to enable paging: Silverlight IEnumerable itemsSource = Enumerable.Range(0, 1000); var pagedSource = new PagedCollectionView(itemsSource); this.radDataPager.Source = pagedSource; this.itemsControl.ItemsSource = pagedSource; WPF IEnumerable itemsSource = Enumerable.Range(0, 1000); var pagedSource = new QueryableCollectionView(itemsSource); this.radDataPager.Source = pagedSource; this.itemsControl.ItemsSource = pagedSource; XAML <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <ListBox Name="itemsControl"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> This will do the trick. It is quite simple, isnt it? The two sample projects in the solution that I have attached are: PagingSimpleCollectionWithWrapping_WPF PagingSimpleCollectionWithWrapping_SL3 III. 2. Binding to RadDataPager.PagedSource In case you do not like this approach there is a better one. When you assign an IEnumerable as the Source of a RadDataPager it will automatically wrap it in a QueryableCollectionView and expose it through its PagedSource property. From then on, you can attach any number of ItemsControls to the PagedSource and they will be automatically paged. Here is how to do this entirely in XAML: Using RadDataPager.PagedSource <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1" Margin="5">     <ListBox Name="itemsControl"              ItemsSource="{Binding PagedSource, ElementName=radDataPager}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding ItemsSource}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> The two sample projects in the solution that I have attached are: PagingSimpleCollectionWithPagedSource_WPF PagingSimpleCollectionWithPagedSource_SL3 IV. Paging collections implementing IPagedCollectionView Those of you who are using WCF RIA Services should feel very lucky. After a quick look with Reflector or the debugger we can see that the DomainDataSource.Data property is in fact an instance of the DomainDataSourceView class. This class implements a handful of useful interfaces: ICollectionView IEnumerable INotifyCollectionChanged IEditableCollectionView IPagedCollectionView INotifyPropertyChanged Luckily, IPagedCollectionView is among them which lets you do the whole paging in the server. So lets do this. We will add a DomainDataSource control to our page/window and connect the items control and the pager to it. Here is how to do this: MainPage <riaControls:DomainDataSource x:Name="invoicesDataSource"                               AutoLoad="True"                               QueryName="GetInvoicesQuery">     <riaControls:DomainDataSource.DomainContext>         <services:ChinookDomainContext/>     </riaControls:DomainDataSource.DomainContext> </riaControls:DomainDataSource> <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <ListBox Name="itemsControl"              ItemsSource="{Binding Data, ElementName=invoicesDataSource}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding Data, ElementName=invoicesDataSource}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> By the way, you can replace the ListBox from the above code snippet with any other ItemsControl. It can be RadGridView, it can be the MS DataGrid, you name it. Essentially, RadDataPager is sending paging commands to the the DomainDataSource.Data. It does not care who, what, or how many different controls are bound to this same Data property of the DomainDataSource control. So if you would like to experiment with this, you can throw in any number of other ItemsControls next to the ListBox, bind them in the same manner, and all of them will be paged by our single RadDataPager. Furthermore, you can throw in any number of RadDataPagers and bind them to the same property. Then when you page with any one of them will automatically update all of the rest. The whole picture is simply beautiful and we can do all of this thanks to WCF RIA Services. The two sample projects (Silverlight only) in the solution that I have attached are: PagingIPagedCollectionView PagingIPagedCollectionView.Web IV. Paging RadGridView While you can replace the ListBox in any of the above examples with a RadGridView, RadGridView offers something extra. Similar to the DomainDataSource.Data property, the RadGridView.Items collection implements the IPagedCollectionView interface. So you are already thinking: Then why not bind the Source property of RadDataPager to RadGridView.Items? Well thats exactly what you can do and you will start paging RadGridView out-of-the-box. It is as simple as that, no code-behind is involved: MainPage <Border Grid.Row="0"         BorderBrush="Black"         BorderThickness="1" Margin="5">     <telerikGrid:RadGridView Name="radGridView"                              ItemsSource="{Binding ItemsSource}"/> </Border> <Border Grid.Row="1"         BorderBrush="Black"         BorderThickness="1"         Margin="5">     <telerikGrid:RadDataPager Name="radDataPager"                               Source="{Binding Items, ElementName=radGridView}"                              PageSize="10"                              IsTotalItemCountFixed="True"                              DisplayMode="All"/> The two sample projects in the solution that I have attached are: PagingRadGridView_SL3 PagingRadGridView_WPF With this last example I think I have covered every possible paging combination. In case you would like to see an example of something that I have not covered, please let me know. Also, make sure you check out those great online examples: WCF RIA Services with DomainDataSource Paging Configurator Endless Paging Paging Any Collection Paging RadGridView Happy Paging! Download Full Source Code Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • android Emulator always stop at "waiting for Home..."

    - by wuwupp
    hi,there, I freshed install Eclipse, jdk, android sdk 1.5 in winxp. but when I run the "hello world" app, the emulator always stop at "andorid" loading message. In eclipse console, it shows "waiting for HOME..." and in DDMS LogCat, it shows following msg: there are some error and warning. So, what's wrong with my case? I have googled lots of results, but no one can help me. Please help me. Many thx 06-13 00:07:54.323: INFO/DEBUG(551): debuggerd: Jun 30 2009 17:00:51 06-13 00:07:54.383: INFO/vold(550): Android Volume Daemon version 2.0 06-13 00:07:54.724: ERROR/flash_image(556): can't find recovery partition 06-13 00:07:55.223: DEBUG/qemud(558): entering main loop 06-13 00:07:55.323: DEBUG/qemud(558): multiplexer_handle_control: unknown control message (18 bytes): 'ko:unknown command' 06-13 00:07:55.493: INFO/vold(550): New MMC card 'SU02G' (serial 1012966) added @ /devices/platform/goldfish_mmc.0/mmc_host/mmc0/mmc0:e118 06-13 00:07:55.773: INFO/vold(550): Disk (blkdev 179:0), 262144 secs (128 MB) 0 partitions 06-13 00:07:55.773: INFO/vold(550): New blkdev 179.0 on media SU02G, media path /devices/platform/goldfish_mmc.0/mmc_host/mmc0/mmc0:e118, Dpp 0 06-13 00:07:55.814: INFO/vold(550): Evaluating dev '/devices/platform/goldfish_mmc.0/mmc_host/mmc0/mmc0:e118/block/mmcblk0' for mountable filesystems for '/sdcard' 06-13 00:07:56.014: ERROR/vold(550): Error opening switch name path '/sys/class/switch/test2' (No such file or directory) 06-13 00:07:56.014: ERROR/vold(550): Error bootstrapping switch '/sys/class/switch/test2' (m) 06-13 00:07:56.073: ERROR/vold(550): Error opening switch name path '/sys/class/switch/test' (No such file or directory) 06-13 00:07:56.073: ERROR/vold(550): Error bootstrapping switch '/sys/class/switch/test' (m) 06-13 00:07:56.073: DEBUG/vold(550): Bootstrapping complete 06-13 00:07:56.743: INFO//system/bin/dosfsck(550): dosfsck 3.0.1 (23 Nov 2008) 06-13 00:07:56.753: INFO//system/bin/dosfsck(550): dosfsck 3.0.1, 23 Nov 2008, FAT32, LFN 06-13 00:07:56.783: INFO//system/bin/dosfsck(550): Checking we can access the last sector of the filesystem 06-13 00:07:56.893: INFO//system/bin/dosfsck(550): Boot sector contents: 06-13 00:07:56.924: INFO//system/bin/dosfsck(550): System ID "MSWIN4.1" 06-13 00:07:56.934: INFO//system/bin/dosfsck(550): Media byte 0xf8 (hard disk) 06-13 00:07:56.953: INFO//system/bin/dosfsck(550): 512 bytes per logical sector 06-13 00:07:56.974: INFO//system/bin/dosfsck(550): 512 bytes per cluster 06-13 00:07:57.005: INFO//system/bin/dosfsck(550): 32 reserved sectors 06-13 00:07:57.013: INFO//system/bin/dosfsck(550): First FAT starts at byte 16384 (sector 32) 06-13 00:07:57.013: INFO//system/bin/dosfsck(550): 2 FATs, 32 bit entries 06-13 00:07:57.023: INFO//system/bin/dosfsck(550): 1040384 bytes per FAT (= 2032 sectors) 06-13 00:07:57.043: INFO//system/bin/dosfsck(550): Root directory start at cluster 2 (arbitrary size) 06-13 00:07:57.043: INFO//system/bin/dosfsck(550): Data area starts at byte 2097152 (sector 4096) 06-13 00:07:57.043: INFO//system/bin/dosfsck(550): 258048 data clusters (132120576 bytes) 06-13 00:07:57.103: INFO//system/bin/dosfsck(550): 9 sectors/track, 2 heads 06-13 00:07:57.103: INFO//system/bin/dosfsck(550): 0 hidden sectors 06-13 00:07:57.123: INFO//system/bin/dosfsck(550): 262144 sectors total 06-13 00:07:57.313: DEBUG/qemud(558): fdhandler_accept_event: accepting on fd 10 06-13 00:07:57.313: DEBUG/qemud(558): created client 0xe078 listening on fd 8 06-13 00:07:57.313: DEBUG/qemud(558): fdhandler_event: disconnect on fd 8 06-13 00:07:57.623: DEBUG/qemud(558): fdhandler_accept_event: accepting on fd 10 06-13 00:07:57.623: DEBUG/qemud(558): created client 0xf028 listening on fd 8 06-13 00:07:57.643: DEBUG/qemud(558): client_fd_receive: attempting registration for service 'gsm' 06-13 00:07:57.763: DEBUG/qemud(558): client_fd_receive: - received channel id 1 06-13 00:08:12.553: INFO//system/bin/dosfsck(550): Checking for unused clusters. 06-13 00:08:13.483: INFO//system/bin/dosfsck(550): Checking free cluster summary. 06-13 00:08:13.643: DEBUG/AndroidRuntime(553): AndroidRuntime START <<<<<<<<<<<<<< 06-13 00:08:13.705: DEBUG/AndroidRuntime(553): CheckJNI is ON 06-13 00:08:13.793: INFO//system/bin/dosfsck(550): /dev/block//vold/179:0: 0 files, 1/258048 clusters 06-13 00:08:14.063: INFO/logwrapper(550): /system/bin/dosfsck terminated by exit(0) 06-13 00:08:14.143: DEBUG/vold(550): Filesystem check completed OK 06-13 00:08:14.683: INFO/vold(550): Sucessfully mounted vfat filesystem 179:0 on /sdcard (safe-mode on) 06-13 00:08:17.023: INFO/(554): ServiceManager: 0xac38 06-13 00:08:17.883: INFO/AudioFlinger(554): AudioFlinger's thread ready to run for output 0 06-13 00:08:18.163: INFO/CameraService(554): CameraService started: pid=554 06-13 00:08:21.824: DEBUG/AndroidRuntime(553): --- registering native functions --- 06-13 00:08:27.813: INFO/Zygote(553): Preloading classes... 06-13 00:08:27.994: DEBUG/dalvikvm(553): GC freed 764 objects / 42216 bytes in 88ms 06-13 00:08:30.234: DEBUG/dalvikvm(553): GC freed 278 objects / 17160 bytes in 48ms 06-13 00:08:33.094: DEBUG/dalvikvm(553): GC freed 208 objects / 12696 bytes in 44ms 06-13 00:08:34.343: DEBUG/dalvikvm(553): Trying to load lib /system/lib/libmedia_jni.so 0x0 06-13 00:08:35.803: DEBUG/dalvikvm(553): Added shared lib /system/lib/libmedia_jni.so 0x0 06-13 00:08:35.903: DEBUG/dalvikvm(553): Trying to load lib /system/lib/libmedia_jni.so 0x0 06-13 00:08:35.903: DEBUG/dalvikvm(553): Shared lib '/system/lib/libmedia_jni.so' already loaded in same CL 0x0 06-13 00:08:36.003: DEBUG/dalvikvm(553): Trying to load lib /system/lib/libmedia_jni.so 0x0 06-13 00:08:36.003: DEBUG/dalvikvm(553): Shared lib '/system/lib/libmedia_jni.so' already loaded in same CL 0x0 06-13 00:08:36.215: DEBUG/dalvikvm(553): Trying to load lib /system/lib/libmedia_jni.so 0x0 06-13 00:08:36.244: DEBUG/dalvikvm(553): Shared lib '/system/lib/libmedia_jni.so' already loaded in same CL 0x0 06-13 00:08:36.455: DEBUG/dalvikvm(553): GC freed 462 objects / 29144 bytes in 70ms 06-13 00:08:44.123: DEBUG/dalvikvm(553): GC freed 3584 objects / 171648 bytes in 125ms 06-13 00:09:10.473: DEBUG/dalvikvm(553): GC freed 11329 objects / 400856 bytes in 196ms 06-13 00:09:17.373: DEBUG/dalvikvm(553): GC freed 10472 objects / 438272 bytes in 199ms 06-13 00:09:24.563: DEBUG/dalvikvm(553): GC freed 10975 objects / 459800 bytes in 202ms 06-13 00:09:46.403: DEBUG/dalvikvm(553): GC freed 14372 objects / 506896 bytes in 252ms 06-13 00:09:53.793: DEBUG/dalvikvm(553): GC freed 11314 objects / 481360 bytes in 215ms 06-13 00:09:57.743: DEBUG/dalvikvm(553): GC freed 5928 objects / 248640 bytes in 195ms 06-13 00:10:01.324: DEBUG/dalvikvm(553): GC freed 349 objects / 37032 bytes in 190ms 06-13 00:10:05.253: DEBUG/dalvikvm(553): GC freed 778 objects / 48376 bytes in 217ms 06-13 00:10:06.564: DEBUG/dalvikvm(553): GC freed 321 objects / 37288 bytes in 219ms 06-13 00:10:08.194: DEBUG/dalvikvm(553): GC freed 477 objects / 29584 bytes in 212ms 06-13 00:10:08.663: DEBUG/dalvikvm(553): Trying to load lib /system/lib/libwebcore.so 0x0 06-13 00:10:09.743: DEBUG/dalvikvm(553): Added shared lib /system/lib/libwebcore.so 0x0 06-13 00:10:11.634: DEBUG/dalvikvm(553): GC freed 441 objects / 26224 bytes in 236ms 06-13 00:10:12.893: DEBUG/dalvikvm(553): GC freed 506 objects / 41464 bytes in 235ms 06-13 00:10:14.153: DEBUG/dalvikvm(553): GC freed 537 objects / 38832 bytes in 239ms 06-13 00:10:15.883: DEBUG/dalvikvm(553): GC freed 342 objects / 22552 bytes in 248ms 06-13 00:10:17.124: DEBUG/dalvikvm(553): GC freed 338 objects / 18736 bytes in 264ms 06-13 00:10:18.523: DEBUG/dalvikvm(553): GC freed 629 objects / 32136 bytes in 260ms 06-13 00:10:38.933: DEBUG/dalvikvm(553): GC freed 14257 objects / 497280 bytes in 368ms 06-13 00:10:46.453: DEBUG/dalvikvm(553): GC freed 11164 objects / 469576 bytes in 360ms 06-13 00:10:52.973: DEBUG/dalvikvm(553): GC freed 7134 objects / 311432 bytes in 339ms 06-13 00:10:55.595: DEBUG/dalvikvm(553): GC freed 752 objects / 43224 bytes in 520ms 06-13 00:10:56.863: DEBUG/dalvikvm(553): GC freed 598 objects / 31496 bytes in 307ms 06-13 00:10:58.543: DEBUG/dalvikvm(553): GC freed 413 objects / 26336 bytes in 355ms 06-13 00:10:59.263: INFO/Zygote(553): ...preloaded 1166 classes in 151403ms. 06-13 00:10:59.683: DEBUG/dalvikvm(553): GC freed 313 objects / 19952 bytes in 343ms 06-13 00:10:59.793: INFO/Zygote(553): Preloading resources... 06-13 00:11:00.683: DEBUG/dalvikvm(553): GC freed 54 objects / 11248 bytes in 340ms 06-13 00:11:05.723: DEBUG/dalvikvm(553): GC freed 337 objects / 15008 bytes in 317ms 06-13 00:11:08.703: DEBUG/dalvikvm(553): GC freed 280 objects / 11768 bytes in 312ms 06-13 00:11:09.303: INFO/Zygote(553): ...preloaded 48 resources in 9513ms. 06-13 00:11:09.795: INFO/Zygote(553): ...preloaded 15 resources in 454ms. 06-13 00:11:10.303: DEBUG/dalvikvm(553): GC freed 118 objects / 8616 bytes in 420ms 06-13 00:11:10.913: DEBUG/dalvikvm(553): GC freed 205 objects / 8104 bytes in 308ms 06-13 00:11:11.344: DEBUG/dalvikvm(553): GC freed 36 objects / 1400 bytes in 320ms 06-13 00:11:11.543: INFO/dalvikvm(553): Splitting out new zygote heap 06-13 00:11:12.973: INFO/dalvikvm(553): System server process 585 has been created 06-13 00:11:13.336: INFO/Zygote(553): Accepting command socket connections 06-13 00:11:14.963: INFO/jdwp(585): received file descriptor 10 from ADB 06-13 00:11:16.843: WARN/System.err(585): Can't dispatch DDM chunk 46454154: no handler defined 06-13 00:11:16.953: WARN/System.err(585): Can't dispatch DDM chunk 4d505251: no handler defined 06-13 00:11:17.763: DEBUG/dalvikvm(585): Trying to load lib /system/lib/libandroid_servers.so 0x0 06-13 00:11:19.714: DEBUG/dalvikvm(585): Added shared lib /system/lib/libandroid_servers.so 0x0 06-13 00:11:20.123: INFO/sysproc(585): Entered system_init() 06-13 00:11:20.223: INFO/sysproc(585): ServiceManager: 0x1017b8 06-13 00:11:20.359: INFO/SurfaceFlinger(585): SurfaceFlinger is starting 06-13 00:11:20.493: INFO/SurfaceFlinger(585): SurfaceFlinger's main thread ready to run. Initializing graphics H/W... 06-13 00:11:20.634: ERROR/MemoryHeapBase(585): error opening /dev/pmem: No such file or directory 06-13 00:11:20.704: ERROR/SurfaceFlinger(585): Couldn't open /sys/power/wait_for_fb_sleep or /sys/power/wait_for_fb_wake 06-13 00:11:22.013: ERROR/GLLogger(585): couldn't load library (Cannot find library) 06-13 00:11:22.103: INFO/SurfaceFlinger(585): EGL informations: 06-13 00:11:22.113: INFO/SurfaceFlinger(585): # of configs : 6 06-13 00:11:22.123: INFO/SurfaceFlinger(585): vendor : Android 06-13 00:11:22.123: INFO/SurfaceFlinger(585): version : 1.31 Android META-EGL 06-13 00:11:22.134: INFO/SurfaceFlinger(585): extensions: 06-13 00:11:22.134: INFO/SurfaceFlinger(585): Client API: OpenGL ES 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): using (fd=22) 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): id = 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): xres = 320 px 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): yres = 480 px 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): xres_virtual = 320 px 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): yres_virtual = 960 px 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): bpp = 16 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): r = 11:5 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): g = 5:6 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): b = 0:5 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): width = 49 mm (165.877548 dpi) 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): height = 74 mm (164.756760 dpi) 06-13 00:11:22.193: INFO/EGLDisplaySurface(585): refresh rate = 60.00 Hz 06-13 00:11:22.533: WARN/HAL(585): load: module=/system/lib/hw/copybit.goldfish.so error=Cannot find library 06-13 00:11:22.543: WARN/HAL(585): load: module=/system/lib/hw/copybit.default.so error=Cannot find library 06-13 00:11:22.553: WARN/SurfaceFlinger(585): ro.sf.lcd_density not defined, using 160 dpi by default. 06-13 00:11:22.644: INFO/SurfaceFlinger(585): OpenGL informations: 06-13 00:11:22.654: INFO/SurfaceFlinger(585): vendor : Android 06-13 00:11:22.654: INFO/SurfaceFlinger(585): renderer : Android PixelFlinger 1.0 06-13 00:11:22.654: INFO/SurfaceFlinger(585): version : OpenGL ES-CM 1.0 06-13 00:11:22.654: INFO/SurfaceFlinger(585): extensions: GL_OES_byte_coordinates GL_OES_fixed_point GL_OES_single_precision GL_OES_read_format GL_OES_compressed_paletted_texture GL_OES_draw_texture GL_OES_matrix_get GL_OES_query_matrix GL_ARB_texture_compression GL_ARB_texture_non_power_of_two GL_ANDROID_direct_texture GL_ANDROID_user_clip_plane GL_ANDROID_vertex_buffer_object GL_ANDROID_generate_mipmap 06-13 00:11:22.673: WARN/HAL(585): load: module=/system/lib/hw/copybit.goldfish.so error=Cannot find library 06-13 00:11:22.683: WARN/HAL(585): load: module=/system/lib/hw/copybit.default.so error=Cannot find library 06-13 00:11:22.703: WARN/HAL(585): load: module=/system/lib/hw/overlay.goldfish.so error=Cannot find library 06-13 00:11:22.713: WARN/HAL(585): load: module=/system/lib/hw/overlay.default.so error=Cannot find library 06-13 00:11:23.663: INFO/sysproc(585): System server: starting Android runtime. 06-13 00:11:23.733: INFO/sysproc(585): System server: starting Android services. 06-13 00:11:23.953: INFO/SystemServer(585): Entered the Android system server! 06-13 00:11:24.303: INFO/sysproc(585): System server: entering thread pool. 06-13 00:11:24.763: ERROR/GLLogger(585): couldn't load library (Cannot find library) 06-13 00:11:25.893: INFO/ARMAssembler(585): generated scanline__00000077:03545404_00000A01_00000000 [ 30 ipp] (51 ins) at [0x18f708:0x18f7d4] in 72796961 ns 06-13 00:11:26.193: INFO/SystemServer(585): Starting Power Manager. 06-13 00:11:26.953: INFO/SystemServer(585): Starting Activity Manager. 06-13 00:11:31.733: INFO/SystemServer(585): Starting telephony registry 06-13 00:11:32.054: INFO/SystemServer(585): Starting Package Manager. 06-13 00:11:32.553: INFO/Installer(585): connecting... 06-13 00:11:32.914: INFO/installd(555): new connection 06-13 00:11:35.193: INFO/PackageManager(585): Got library android.awt in /system/framework/android.awt.jar 06-13 00:11:35.313: INFO/PackageManager(585): Got library android.test.runner in /system/framework/android.test.runner.jar 06-13 00:11:35.324: INFO/PackageManager(585): Got library com.android.im.plugin in /system/framework/com.android.im.plugin.jar 06-13 00:11:44.643: DEBUG/PackageManager(585): Scanning app dir /system/framework 06-13 00:11:49.513: DEBUG/PackageManager(585): Scanning app dir /system/app 06-13 00:11:51.493: DEBUG/dalvikvm(585): GC freed 6088 objects / 251280 bytes in 1237ms 06-13 00:12:27.497: DEBUG/dalvikvm(585): GC freed 3435 objects / 216088 bytes in 792ms 06-13 00:12:29.213: DEBUG/PackageManager(585): Scanning app dir /data/app 06-13 00:12:30.223: DEBUG/PackageManager(585): Scanning app dir /data/app-private 06-13 00:12:30.425: INFO/PackageManager(585): Time to scan packages: 47.319 seconds 06-13 00:12:30.703: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.providers.contacts 06-13 00:12:30.803: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.cp in package com.android.providers.contacts 06-13 00:12:30.853: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.development 06-13 00:12:30.913: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.ALL_SERVICES in package com.android.development 06-13 00:12:31.133: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.YouTubeUser in package com.android.development 06-13 00:12:31.143: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.ACCESS_GOOGLE_PASSWORD in package com.android.development 06-13 00:12:31.234: WARN/PackageManager(585): Unknown permission com.google.android.providers.gmail.permission.WRITE_GMAIL in package com.android.settings 06-13 00:12:31.254: WARN/PackageManager(585): Unknown permission com.google.android.providers.gmail.permission.READ_GMAIL in package com.android.settings 06-13 00:12:31.303: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.settings 06-13 00:12:31.683: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH in package com.android.browser 06-13 00:12:31.803: WARN/PackageManager(585): Unknown permission com.google.android.googleapps.permission.GOOGLE_AUTH.mail in package com.android.contacts 06-13 00:12:34.603: DEBUG/dalvikvm(585): GC freed 2851 objects / 161304 bytes in 845ms 06-13 00:12:35.403: INFO/SystemServer(585): Starting Content Manager. 06-13 00:12:39.954: WARN/ActivityManager(585): Unable to start service Intent { action=android.accounts.IAccountsService comp={com.google.android.googleapps/com.google.android.googleapps.GoogleLoginService} }: not found 06-13 00:12:40.063: WARN/AccountMonitor(585): Couldn't connect to Intent { action=android.accounts.IAccountsService comp={com.google.android.googleapps/com.google.android.googleapps.GoogleLoginService} } (Missing service?) 06-13 00:12:40.253: INFO/SystemServer(585): Starting System Content Providers. 06-13 00:12:40.553: INFO/ActivityThread(585): Publishing provider settings: com.android.providers.settings.SettingsProvider 06-13 00:12:41.433: INFO/ActivityThread(585): Publishing provider sync: android.content.SyncProvider 06-13 00:12:41.683: INFO/SystemServer(585): Starting Battery Service. 06-13 00:12:42.293: ERROR/BatteryService(585): Could not open '/sys/class/power_supply/usb/online' 06-13 00:12:42.433: ERROR/BatteryService(585): Could not open '/sys/class/power_supply/battery/batt_vol' 06-13 00:12:42.543: ERROR/BatteryService(585): Could not open '/sys/class/power_supply/battery/batt_temp' 06-13 00:12:42.933: INFO/SystemServer(585): Starting Hardware Service. 06-13 00:12:43.398: DEBUG/qemud(558): fdhandler_accept_event: accepting on fd 10 06-13 00:12:43.623: DEBUG/qemud(558): created client 0x10fd8 listening on fd 11 06-13 00:12:43.743: DEBUG/qemud(558): client_fd_receive: attempting registration for service 'hw-control' 06-13 00:12:43.873: DEBUG/qemud(558): client_fd_receive: - received channel id 2 06-13 00:15:20.695: WARN/SurfaceFlinger(585): executeScheduledBroadcasts() skipped, contention on the client. We'll try again later...

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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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  • Sorting Algorithms

    - by MarkPearl
    General Every time I go back to university I find myself wading through sorting algorithms and their implementation in C++. Up to now I haven’t really appreciated their true value. However as I discovered this last week with Dictionaries in C# – having a knowledge of some basic programming principles can greatly improve the performance of a system and make one think twice about how to tackle a problem. I’m going to cover briefly in this post the following: Selection Sort Insertion Sort Shellsort Quicksort Mergesort Heapsort (not complete) Selection Sort Array based selection sort is a simple approach to sorting an unsorted array. Simply put, it repeats two basic steps to achieve a sorted collection. It starts with a collection of data and repeatedly parses it, each time sorting out one element and reducing the size of the next iteration of parsed data by one. So the first iteration would go something like this… Go through the entire array of data and find the lowest value Place the value at the front of the array The second iteration would go something like this… Go through the array from position two (position one has already been sorted with the smallest value) and find the next lowest value in the array. Place the value at the second position in the array This process would be completed until the entire array had been sorted. A positive about selection sort is that it does not make many item movements. In fact, in a worst case scenario every items is only moved once. Selection sort is however a comparison intensive sort. If you had 10 items in a collection, just to parse the collection you would have 10+9+8+7+6+5+4+3+2=54 comparisons to sort regardless of how sorted the collection was to start with. If you think about it, if you applied selection sort to a collection already sorted, you would still perform relatively the same number of iterations as if it was not sorted at all. Many of the following algorithms try and reduce the number of comparisons if the list is already sorted – leaving one with a best case and worst case scenario for comparisons. Likewise different approaches have different levels of item movement. Depending on what is more expensive, one may give priority to one approach compared to another based on what is more expensive, a comparison or a item move. Insertion Sort Insertion sort tries to reduce the number of key comparisons it performs compared to selection sort by not “doing anything” if things are sorted. Assume you had an collection of numbers in the following order… 10 18 25 30 23 17 45 35 There are 8 elements in the list. If we were to start at the front of the list – 10 18 25 & 30 are already sorted. Element 5 (23) however is smaller than element 4 (30) and so needs to be repositioned. We do this by copying the value at element 5 to a temporary holder, and then begin shifting the elements before it up one. So… Element 5 would be copied to a temporary holder 10 18 25 30 23 17 45 35 – T 23 Element 4 would shift to Element 5 10 18 25 30 30 17 45 35 – T 23 Element 3 would shift to Element 4 10 18 25 25 30 17 45 35 – T 23 Element 2 (18) is smaller than the temporary holder so we put the temporary holder value into Element 3. 10 18 23 25 30 17 45 35 – T 23   We now have a sorted list up to element 6. And so we would repeat the same process by moving element 6 to a temporary value and then shifting everything up by one from element 2 to element 5. As you can see, one major setback for this technique is the shifting values up one – this is because up to now we have been considering the collection to be an array. If however the collection was a linked list, we would not need to shift values up, but merely remove the link from the unsorted value and “reinsert” it in a sorted position. Which would reduce the number of transactions performed on the collection. So.. Insertion sort seems to perform better than selection sort – however an implementation is slightly more complicated. This is typical with most sorting algorithms – generally, greater performance leads to greater complexity. Also, insertion sort performs better if a collection of data is already sorted. If for instance you were handed a sorted collection of size n, then only n number of comparisons would need to be performed to verify that it is sorted. It’s important to note that insertion sort (array based) performs a number item moves – every time an item is “out of place” several items before it get shifted up. Shellsort – Diminishing Increment Sort So up to now we have covered Selection Sort & Insertion Sort. Selection Sort makes many comparisons and insertion sort (with an array) has the potential of making many item movements. Shellsort is an approach that takes the normal insertion sort and tries to reduce the number of item movements. In Shellsort, elements in a collection are viewed as sub-collections of a particular size. Each sub-collection is sorted so that the elements that are far apart move closer to their final position. Suppose we had a collection of 15 elements… 10 20 15 45 36 48 7 60 18 50 2 19 43 30 55 First we may view the collection as 7 sub-collections and sort each sublist, lets say at intervals of 7 10 60 55 – 20 18 – 15 50 – 45 2 – 36 19 – 48 43 – 7 30 10 55 60 – 18 20 – 15 50 – 2 45 – 19 36 – 43 48 – 7 30 (Sorted) We then sort each sublist at a smaller inter – lets say 4 10 55 60 18 – 20 15 50 2 – 45 19 36 43 – 48 7 30 10 18 55 60 – 2 15 20 50 – 19 36 43 45 – 7 30 48 (Sorted) We then sort elements at a distance of 1 (i.e. we apply a normal insertion sort) 10 18 55 60 2 15 20 50 19 36 43 45 7 30 48 2 7 10 15 18 19 20 30 36 43 45 48 50 55 (Sorted) The important thing with shellsort is deciding on the increment sequence of each sub-collection. From what I can tell, there isn’t any definitive method and depending on the order of your elements, different increment sequences may perform better than others. There are however certain increment sequences that you may want to avoid. An even based increment sequence (e.g. 2 4 8 16 32 …) should typically be avoided because it does not allow for even elements to be compared with odd elements until the final sort phase – which in a way would negate many of the benefits of using sub-collections. The performance on the number of comparisons and item movements of Shellsort is hard to determine, however it is considered to be considerably better than the normal insertion sort. Quicksort Quicksort uses a divide and conquer approach to sort a collection of items. The collection is divided into two sub-collections – and the two sub-collections are sorted and combined into one list in such a way that the combined list is sorted. The algorithm is in general pseudo code below… Divide the collection into two sub-collections Quicksort the lower sub-collection Quicksort the upper sub-collection Combine the lower & upper sub-collection together As hinted at above, quicksort uses recursion in its implementation. The real trick with quicksort is to get the lower and upper sub-collections to be of equal size. The size of a sub-collection is determined by what value the pivot is. Once a pivot is determined, one would partition to sub-collections and then repeat the process on each sub collection until you reach the base case. With quicksort, the work is done when dividing the sub-collections into lower & upper collections. The actual combining of the lower & upper sub-collections at the end is relatively simple since every element in the lower sub-collection is smaller than the smallest element in the upper sub-collection. Mergesort With quicksort, the average-case complexity was O(nlog2n) however the worst case complexity was still O(N*N). Mergesort improves on quicksort by always having a complexity of O(nlog2n) regardless of the best or worst case. So how does it do this? Mergesort makes use of the divide and conquer approach to partition a collection into two sub-collections. It then sorts each sub-collection and combines the sorted sub-collections into one sorted collection. The general algorithm for mergesort is as follows… Divide the collection into two sub-collections Mergesort the first sub-collection Mergesort the second sub-collection Merge the first sub-collection and the second sub-collection As you can see.. it still pretty much looks like quicksort – so lets see where it differs… Firstly, mergesort differs from quicksort in how it partitions the sub-collections. Instead of having a pivot – merge sort partitions each sub-collection based on size so that the first and second sub-collection of relatively the same size. This dividing keeps getting repeated until the sub-collections are the size of a single element. If a sub-collection is one element in size – it is now sorted! So the trick is how do we put all these sub-collections together so that they maintain their sorted order. Sorted sub-collections are merged into a sorted collection by comparing the elements of the sub-collection and then adjusting the sorted collection. Lets have a look at a few examples… Assume 2 sub-collections with 1 element each 10 & 20 Compare the first element of the first sub-collection with the first element of the second sub-collection. Take the smallest of the two and place it as the first element in the sorted collection. In this scenario 10 is smaller than 20 so 10 is taken from sub-collection 1 leaving that sub-collection empty, which means by default the next smallest element is in sub-collection 2 (20). So the sorted collection would be 10 20 Lets assume 2 sub-collections with 2 elements each 10 20 & 15 19 So… again we would Compare 10 with 15 – 10 is the winner so we add it to our sorted collection (10) leaving us with 20 & 15 19 Compare 20 with 15 – 15 is the winner so we add it to our sorted collection (10 15) leaving us with 20 & 19 Compare 20 with 19 – 19 is the winner so we add it to our sorted collection (10 15 19) leaving us with 20 & _ 20 is by default the winner so our sorted collection is 10 15 19 20. Make sense? Heapsort (still needs to be completed) So by now I am tired of sorting algorithms and trying to remember why they were so important. I think every year I go through this stuff I wonder to myself why are we made to learn about selection sort and insertion sort if they are so bad – why didn’t we just skip to Mergesort & Quicksort. I guess the only explanation I have for this is that sometimes you learn things so that you can implement them in future – and other times you learn things so that you know it isn’t the best way of implementing things and that you don’t need to implement it in future. Anyhow… luckily this is going to be the last one of my sorts for today. The first step in heapsort is to convert a collection of data into a heap. After the data is converted into a heap, sorting begins… So what is the definition of a heap? If we have to convert a collection of data into a heap, how do we know when it is a heap and when it is not? The definition of a heap is as follows: A heap is a list in which each element contains a key, such that the key in the element at position k in the list is at least as large as the key in the element at position 2k +1 (if it exists) and 2k + 2 (if it exists). Does that make sense? At first glance I’m thinking what the heck??? But then after re-reading my notes I see that we are doing something different – up to now we have really looked at data as an array or sequential collection of data that we need to sort – a heap represents data in a slightly different way – although the data is stored in a sequential collection, for a sequential collection of data to be in a valid heap – it is “semi sorted”. Let me try and explain a bit further with an example… Example 1 of Potential Heap Data Assume we had a collection of numbers as follows 1[1] 2[2] 3[3] 4[4] 5[5] 6[6] For this to be a valid heap element with value of 1 at position [1] needs to be greater or equal to the element at position [3] (2k +1) and position [4] (2k +2). So in the above example, the collection of numbers is not in a valid heap. Example 2 of Potential Heap Data Lets look at another collection of numbers as follows 6[1] 5[2] 4[3] 3[4] 2[5] 1[6] Is this a valid heap? Well… element with the value 6 at position 1 must be greater or equal to the element at position [3] and position [4]. Is 6 > 4 and 6 > 3? Yes it is. Lets look at element 5 as position 2. It must be greater than the values at [4] & [5]. Is 5 > 3 and 5 > 2? Yes it is. If you continued to examine this second collection of data you would find that it is in a valid heap based on the definition of a heap.

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  • Unable to connect to Samba printer

    - by user127236
    I have a headless Ubuntu 12.04 server for files and printers. It shares files via Samba just fine. However, the HP PSC-750xi connected to the server via USB is not accessible from my Ubuntu 12.04 laptop. I can browse for it in the Printing control panel, but any attempt to authenticate my ID to the printer with my user credentials results in the error "This print share is not accessible". I have included the Samba smb.conf file below. Any help appreciated. Thanks... JGB # # Sample configuration file for the Samba suite for Debian GNU/Linux. # # # This is the main Samba configuration file. You should read the # smb.conf(5) manual page in order to understand the options listed # here. Samba has a huge number of configurable options most of which # are not shown in this example # # Some options that are often worth tuning have been included as # commented-out examples in this file. # - When such options are commented with ";", the proposed setting # differs from the default Samba behaviour # - When commented with "#", the proposed setting is the default # behaviour of Samba but the option is considered important # enough to be mentioned here # # NOTE: Whenever you modify this file you should run the command # "testparm" to check that you have not made any basic syntactic # errors. # A well-established practice is to name the original file # "smb.conf.master" and create the "real" config file with # testparm -s smb.conf.master >smb.conf # This minimizes the size of the really used smb.conf file # which, according to the Samba Team, impacts performance # However, use this with caution if your smb.conf file contains nested # "include" statements. See Debian bug #483187 for a case # where using a master file is not a good idea. # #======================= Global Settings ======================= [global] log file = /var/log/samba/log.%m passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* . obey pam restrictions = yes map to guest = bad user encrypt passwords = true passwd program = /usr/bin/passwd %u passdb backend = tdbsam dns proxy = no writeable = yes server string = %h server (Samba, Ubuntu) unix password sync = yes workgroup = WORKGROUP syslog = 0 panic action = /usr/share/samba/panic-action %d usershare allow guests = yes max log size = 1000 pam password change = yes ## Browsing/Identification ### # Change this to the workgroup/NT-domain name your Samba server will part of # server string is the equivalent of the NT Description field # Windows Internet Name Serving Support Section: # WINS Support - Tells the NMBD component of Samba to enable its WINS Server # wins support = no # WINS Server - Tells the NMBD components of Samba to be a WINS Client # Note: Samba can be either a WINS Server, or a WINS Client, but NOT both ; wins server = w.x.y.z # This will prevent nmbd to search for NetBIOS names through DNS. # What naming service and in what order should we use to resolve host names # to IP addresses ; name resolve order = lmhosts host wins bcast #### Networking #### # The specific set of interfaces / networks to bind to # This can be either the interface name or an IP address/netmask; # interface names are normally preferred ; interfaces = 127.0.0.0/8 eth0 # Only bind to the named interfaces and/or networks; you must use the # 'interfaces' option above to use this. # It is recommended that you enable this feature if your Samba machine is # not protected by a firewall or is a firewall itself. However, this # option cannot handle dynamic or non-broadcast interfaces correctly. ; bind interfaces only = yes #### Debugging/Accounting #### # This tells Samba to use a separate log file for each machine # that connects # Cap the size of the individual log files (in KiB). # If you want Samba to only log through syslog then set the following # parameter to 'yes'. # syslog only = no # We want Samba to log a minimum amount of information to syslog. Everything # should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log # through syslog you should set the following parameter to something higher. # Do something sensible when Samba crashes: mail the admin a backtrace ####### Authentication ####### # "security = user" is always a good idea. This will require a Unix account # in this server for every user accessing the server. See # /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/ServerType.html # in the samba-doc package for details. # security = user # You may wish to use password encryption. See the section on # 'encrypt passwords' in the smb.conf(5) manpage before enabling. # If you are using encrypted passwords, Samba will need to know what # password database type you are using. # This boolean parameter controls whether Samba attempts to sync the Unix # password with the SMB password when the encrypted SMB password in the # passdb is changed. # For Unix password sync to work on a Debian GNU/Linux system, the following # parameters must be set (thanks to Ian Kahan <<[email protected]> for # sending the correct chat script for the passwd program in Debian Sarge). # This boolean controls whether PAM will be used for password changes # when requested by an SMB client instead of the program listed in # 'passwd program'. The default is 'no'. # This option controls how unsuccessful authentication attempts are mapped # to anonymous connections ########## Domains ########### # Is this machine able to authenticate users. Both PDC and BDC # must have this setting enabled. If you are the BDC you must # change the 'domain master' setting to no # ; domain logons = yes # # The following setting only takes effect if 'domain logons' is set # It specifies the location of the user's profile directory # from the client point of view) # The following required a [profiles] share to be setup on the # samba server (see below) ; logon path = \\%N\profiles\%U # Another common choice is storing the profile in the user's home directory # (this is Samba's default) # logon path = \\%N\%U\profile # The following setting only takes effect if 'domain logons' is set # It specifies the location of a user's home directory (from the client # point of view) ; logon drive = H: # logon home = \\%N\%U # The following setting only takes effect if 'domain logons' is set # It specifies the script to run during logon. The script must be stored # in the [netlogon] share # NOTE: Must be store in 'DOS' file format convention ; logon script = logon.cmd # This allows Unix users to be created on the domain controller via the SAMR # RPC pipe. The example command creates a user account with a disabled Unix # password; please adapt to your needs ; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u # This allows machine accounts to be created on the domain controller via the # SAMR RPC pipe. # The following assumes a "machines" group exists on the system ; add machine script = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u # This allows Unix groups to be created on the domain controller via the SAMR # RPC pipe. ; add group script = /usr/sbin/addgroup --force-badname %g ########## Printing ########## # If you want to automatically load your printer list rather # than setting them up individually then you'll need this # load printers = yes # lpr(ng) printing. You may wish to override the location of the # printcap file ; printing = bsd ; printcap name = /etc/printcap # CUPS printing. See also the cupsaddsmb(8) manpage in the # cupsys-client package. ; printing = cups ; printcap name = cups ############ Misc ############ # Using the following line enables you to customise your configuration # on a per machine basis. The %m gets replaced with the netbios name # of the machine that is connecting ; include = /home/samba/etc/smb.conf.%m # Most people will find that this option gives better performance. # See smb.conf(5) and /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/speed.html # for details # You may want to add the following on a Linux system: # SO_RCVBUF=8192 SO_SNDBUF=8192 # socket options = TCP_NODELAY # The following parameter is useful only if you have the linpopup package # installed. The samba maintainer and the linpopup maintainer are # working to ease installation and configuration of linpopup and samba. ; message command = /bin/sh -c '/usr/bin/linpopup "%f" "%m" %s; rm %s' & # Domain Master specifies Samba to be the Domain Master Browser. If this # machine will be configured as a BDC (a secondary logon server), you # must set this to 'no'; otherwise, the default behavior is recommended. # domain master = auto # Some defaults for winbind (make sure you're not using the ranges # for something else.) ; idmap uid = 10000-20000 ; idmap gid = 10000-20000 ; template shell = /bin/bash # The following was the default behaviour in sarge, # but samba upstream reverted the default because it might induce # performance issues in large organizations. # See Debian bug #368251 for some of the consequences of *not* # having this setting and smb.conf(5) for details. ; winbind enum groups = yes ; winbind enum users = yes # Setup usershare options to enable non-root users to share folders # with the net usershare command. # Maximum number of usershare. 0 (default) means that usershare is disabled. ; usershare max shares = 100 # Allow users who've been granted usershare privileges to create # public shares, not just authenticated ones #======================= Share Definitions ======================= # Un-comment the following (and tweak the other settings below to suit) # to enable the default home directory shares. This will share each # user's home director as \\server\username ;[homes] ; comment = Home Directories ; browseable = no # By default, the home directories are exported read-only. Change the # next parameter to 'no' if you want to be able to write to them. ; read only = yes # File creation mask is set to 0700 for security reasons. If you want to # create files with group=rw permissions, set next parameter to 0775. ; create mask = 0700 # Directory creation mask is set to 0700 for security reasons. If you want to # create dirs. with group=rw permissions, set next parameter to 0775. ; directory mask = 0700 # By default, \\server\username shares can be connected to by anyone # with access to the samba server. Un-comment the following parameter # to make sure that only "username" can connect to \\server\username # The following parameter makes sure that only "username" can connect # # This might need tweaking when using external authentication schemes ; valid users = %S # Un-comment the following and create the netlogon directory for Domain Logons # (you need to configure Samba to act as a domain controller too.) ;[netlogon] ; comment = Network Logon Service ; path = /home/samba/netlogon ; guest ok = yes ; read only = yes # Un-comment the following and create the profiles directory to store # users profiles (see the "logon path" option above) # (you need to configure Samba to act as a domain controller too.) # The path below should be writable by all users so that their # profile directory may be created the first time they log on ;[profiles] ; comment = Users profiles ; path = /home/samba/profiles ; guest ok = no ; browseable = no ; create mask = 0600 ; directory mask = 0700 [printers] comment = All Printers browseable = no path = /var/spool/samba printable = yes guest ok = no read only = yes create mask = 0700 # Windows clients look for this share name as a source of downloadable # printer drivers [print$] comment = Printer Drivers browseable = yes writeable = no path = /var/lib/samba/printers # Uncomment to allow remote administration of Windows print drivers. # You may need to replace 'lpadmin' with the name of the group your # admin users are members of. # Please note that you also need to set appropriate Unix permissions # to the drivers directory for these users to have write rights in it ; write list = root, @lpadmin # A sample share for sharing your CD-ROM with others. ;[cdrom] ; comment = Samba server's CD-ROM ; read only = yes ; locking = no ; path = /cdrom ; guest ok = yes # The next two parameters show how to auto-mount a CD-ROM when the # cdrom share is accesed. For this to work /etc/fstab must contain # an entry like this: # # /dev/scd0 /cdrom iso9660 defaults,noauto,ro,user 0 0 # # The CD-ROM gets unmounted automatically after the connection to the # # If you don't want to use auto-mounting/unmounting make sure the CD # is mounted on /cdrom # ; preexec = /bin/mount /cdrom ; postexec = /bin/umount /cdrom [mediafiles] path = /media/multimedia/

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  • CodePlex Daily Summary for Saturday, March 17, 2012

    CodePlex Daily Summary for Saturday, March 17, 2012Popular ReleasesAutoSPEditor: AutoSPEditor Installer: Installs the current version of the AutoSPEditor using ClickOnce. Your application will be updated automatically.Javascript .NET: Javascript .NET v0.6: Upgraded to the latest stable branch of v8 (/tags/3.9.18), and switched to using their scons build system. We no longer include v8 source code as part of this project's source code. Simultaneous multithreaded use of v8 now supported (v8 Isolates), although different contexts may not share objects or call each other. 64-bit .Net 4.0 DLL now included. (Download now includes x86 and x64 for both .Net 3.5 and .Net 4.0.)MyRouter (Virtual WiFi Router): MyRouter 1.0.6: This release should be more stable there were a few bug fixes including the x64 issue as well as an error popping up when MyRouter started this was caused by a NULL valuePulse: Pulse Beta 4: This version is still in development but should include: Logging and error handling have been greatly improved. If you run into an error or Pulse crashes make sure to check the Log folder for a recently modified log file so you can report the details of the issue A bunch of new features for the Wallbase.cc provider. Cleaner separation between inputs, downloading and output. Input and downloading are fairly clean now but outputs are still mixed up in the mix which I'm trying to resolve ...Google Books Downloader for Windows: Google Books Downloader-2.0.0.0.: Google Books DownloaderFinestra Virtual Desktops: 2.5.4501: This is a very minor update release. Please see the information about the 2.5 and 2.5.4500 releases for more information on recent changes. This update did not even have an automatic update triggered for it. Adds error checking and reporting to all threads, not only those with message loopsAcDown????? - Anime&Comic Downloader: AcDown????? v3.9.2: ?? ●AcDown??????????、??、??????,????1M,????,????,?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。??????AcPlay?????,??????、????????????????。 ● AcDown???????????????????????????,???,???????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ????????????? ??:????????Windows XP???,?????????.NET Framework 2.0???(x86),?????"?????????"??? ??????????????,??????????: ??"AcDo...ArcGIS Editor for OpenStreetMap: ArcGIS Editor for OSM 2.0 Release Candidate: Your feedback is welcome - and this is your last chance to get your fixes in for this version! Includes installer for both Feature Server extension and Desktop extension, enhanced functionality for the Desktop tools, and enhanced built-in Javascript Editor for the Feature Server component. This release candidate includes fixes to beta 4 that accommodate domain users for setting up the Server Component, and fixes for reporting/uploading references tracked in the revision table. See Code In-P...C.B.R. : Comic Book Reader: CBR 0.6: 20 Issue trackers are closed and a lot of bugs too Localize view is now MVVM and delete is working. Added the unused flag (take care that it goes to true only when displaying screen elements) Backstage - new input/output format choice control for the conversion Backstage - Add display, behaviour and register file type options in the extended options dialog Explorer list view has been transformed to a custom control. New group header, colunms order and size are saved Single insta...Windows Azure Toolkit for Windows 8: Windows Azure Toolkit for Windows 8 Consumer Prv: Windows Azure Toolkit for Windows 8 Consumer Preview - Preview Release v1.2.1Minor updates to setup experience: Check for WebPI before install Dependency Check updated to support the following VS 11 and VS 2010 SKUs Ultimate, Premium, Professional and Express Certs Windows Azure Toolkit for Windows 8 Consumer Preview - Preview Release v1.2.0 Please download this for Windows Azure Toolkit for Windows 8 functionality on Windows 8 Consumer Preview. The core features of the toolkit include:...Facebook Graph Toolkit: Facebook Graph Toolkit 3.0: ships with JSON Toolkit v3.0, offering parse speed up to 10 times of last version supports Facebook's new auth dialog supports new extend access token endpoint new example Page Tab app filter Graph Api connections using dates fixed bugs in Page Tab appsCODE Framework: 4.0.20312.0: This version includes significant improvements in the WPF system (and the WPF MVVM/MVC system). This includes new styles for Metro controls and layouts. Improved color handling. It also includes an improved theme/style swapping engine down to active (open) views. There also are various other enhancements and small fixes throughout the entire framework.ScintillaNET: ScintillaNET 2.4: 3/12/2012 Jacob Slusser Added support for annotations. Issues Fixed with this Release Issue # Title 25012 25012 25018 25018 25023 25023 25014 25014 Visual Studio ALM Quick Reference Guidance: v3 - For Visual Studio 11: RELEASE README Welcome to the BETA release of the Quick Reference Guide preview As this is a BETA release and the quality bar for the final Release has not been achieved, we value your candid feedback and recommend that you do not use or deploy these BETA artifacts in a production environment. Quality-Bar Details Documentation has been reviewed by Visual Studio ALM Rangers Documentation has not been through an independent technical review Documentation ...AvalonDock: AvalonDock 2.0.0345: Welcome to early alpha release of AvalonDock 2.0 I've completely rewritten AvalonDock in order to take full advantage of the MVVM pattern. New version also boost a lot of new features: 1) Deep separation between model and layout. 2) Full WPF binding support thanks to unified logical tree between main docking manager, auto-hide windows and floating windows. 3) Support for Aero semi-maximized windows feature. 4) Support for multiple panes in the same floating windows. For a short list of new f...Windows Azure PowerShell Cmdlets: Windows Azure PowerShell Cmdlets 2.2.2: Changes Added Start Menu Item for Easy Startup Added Link to Getting Started Document Added Ability to Persist Subscription Data to Disk Fixed Get-Deployment to not throw on empty slot Simplified numerous default values for cmdlets Breaking Changes: -SubscriptionName is now mandatory in Set-Subscription. -DefaultStorageAccountName and -DefaultStorageAccountKey parameters were removed from Set-Subscription. Instead, when adding multiple accounts to a subscription, each one needs to be added ...IronPython: 2.7.2.1: On behalf of the IronPython team, I'm happy to announce the final release IronPython 2.7.2. This release includes everything from IronPython 54498 and 62475 as well. Like all IronPython 2.7-series releases, .NET 4 is required to install it. Installing this release will replace any existing IronPython 2.7-series installation. Unlike previous releases, the assemblies for all supported platforms are included in the installer as well as the zip package, in the "Platforms" directory. IronPython 2...Kooboo CMS: Kooboo CMS 3.2.0.0: Breaking changes: When upgrade from previous versions, MUST reset the all the content type templates, otherwise the content manager might get a compile error. New features Integrate with Windows azure. See: http://wiki.kooboo.com/?wiki=Kooboo CMS on Azure Complete solution to deploy on load balance servers. See: http://wiki.kooboo.com/?wiki=Kooboo CMS load balance Update Jquery and Jquery ui to the lastest version(Jquery 1.71, Jquery UI 1.8.16). Tree style text content editing. See:h...Extensions for Reactive Extensions (Rxx): Rxx 1.3: Please read the latest release notes for details about what's new. Related Work Items Content SummaryRxx provides the following features. See the Documentation for details. Many IObservable<T> extension methods and IEnumerable<T> extension methods. Many wrappers that convert asynchronous Framework Class Library APIs into observables. Many useful types such as ListSubject<T>, DictionarySubject<T>, CommandSubject, ViewModel, ObservableDynamicObject, Either<TLeft, TRight>, Maybe<T>, Scala...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.47: Properly output escaped characters in CSS identifiers throw an EOF error when parsing a CSS selector that doesn't end in a declaration block chased down a stack-overflow issue with really large JS sources. Needed to flatten out the AST tree for adjacent expression statements that the application merges into a single expression statement, or that already contain large, comma-separated expressions in the original source. fix issue #17569: tie together the -debug switch with the DEBUG defi...New ProjectsCOBOL Bubble Sort: The famous Bubble Sort algorithm using COBOLCross Site Media Dashboard (webpart) for SharePoint video content: View video content in easy to configure dashboard structure. Supports a vast range of video formatsDataObjects.Net Samples: DataObjects.Net SamplesDev Tracking Tool: Dev Tracking Tool is thought to help software developers keeping track of their activities in a fast way, and use these informations for later update of tasks in other informatic systems (i.e.: tracking tasks in TFS and/or other tracking tools).Governance Checklist - Create/manage your Governance Checklist: Governance Checklist - Create/manage your Governance Checklist. SharePoint Governance Checklist generated as a starting point however you can update to your own criteria. Visual Guages to show the status of your governance progresslibspotify.NET - a managed interop library for libspotify: libspotify.NET is a simple interop wrapper library for libspotify written in C#. It enables .NET developers to write applications that can browse, search, and stream digital music from the Spotify platform. This project is compatible with libspotify API version 10.1.16. Requires libspotify.dll, a Spotify premium account, and an application API key. More info on the libspotify API at http://developer.spotify.com/en/libspotify/overview/ Media.Net: All-In-One Media Player for Windows XP, Vista, Windows 7 and Windows 8.MisTutoriales: MisTutoriales Ejemplos de programación.mobile video: mobile videoMugen MVVM Toolkit: Mugen MVVM Toolkit makes it easier to develop Silverlight, WPF and WP7 applications using the Model-View-ViewModel design pattern. It is very easy to use. It combines the pattern of DI (dependency injection) and MVVM (Model-View-ViewModel).Project SIMPLE Orca: SIMPLE makes it easier for non-programmers to create simple applications. You'll no longer have to learn an entire language in order to create that simple application you've been stressing over. S imple And I deal M acroed P rogramming L anguage For E aseRelational data Transfer Application: Relational data Transfer Application helps to move data scenarios from One relational database to other Relational database without moving entire tables. Basically this applciation moves a given data row along with its relational data to destination database. rGUI: rGUI is an open source .NET front-end for Robocopy written in C#. It is designed for users already familiar with the Robocopy command-line switches and what they do, but who want the command parameters presented in a visual way.S#: Spontaneous Sharp: A mix of very easy to use c# libraries, born out of spontaneous needs to simplify a large number of programming tasks in .NET C#.SDF - Smart Document Framework: Smart Document Framework offers an alternative to the FlowDocument which provides a simpler rendering engine and allows for better pagination.Shatong: Shatong SystemSPD 2007 Custom Activity Pause Until CheckOut = None: This activity can be added to the beginning of a SharePoint Designer 2007 workflow to pause the workflow until the item is no longer checked out (soft or hard checkout)Spontaneous XNA Library (SXL): Yet another XNA Library that has arisen from various spontaneous needs. Hopefully it can be as helpful to others as it has been to me.TeaFiles.Net - time series storage: TeaFiles.Net is an API for TeaFiles that makes it easy to store and exchange time series data between .Net programs and C++, Python, R and other applications. Written in C#. Find more details about the file specification, other APIs and tools at discretelogics.comTypePipe: TypePipe allows you to modify existing CLR types using a simple, expression-based API. Modifications from several tools and libraries (AOP, IoC etc.) can be combined. Types are generated via Reflection.Emit or user-defined back-ends.UCB_12_1: This is a research projectUCB_12_2: UCB_12_2UCB_12_3: UCB_12_3UCB_12_4: UCB_12_4UCB_12_Common: UCB_12_CommonVG Task Manager: task manager demo project created by Vivek Gupta.WP7 Map Control: Lightweight universal map control for Windows Phone 7xRM#: xRM# is focused on boosting productivity while developing JavaScript customizations for Microsoft Dynamics CRM 2011. xRM# provided a platform to scribble code in C# and translating them to JavaScript snippet for xRM customizations. Developers can benefit from structural and coherent flow of using existing C# coding guidelines. Pseudo data types, IntelliSense and Code Documentation reduce code look-ups and increase productivity. xRM# also supports deploying generated scripts as minified ver...

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  • C#/.NET Little Wonders: ConcurrentBag and BlockingCollection

    - by James Michael Hare
    In the first week of concurrent collections, began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  The last post discussed the ConcurrentDictionary<T> .  Finally this week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see C#/.NET Little Wonders: A Redux. Recap As you'll recall from the previous posts, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  With .NET 4.0, a new breed of collections was born in the System.Collections.Concurrent namespace.  Of these, the final concurrent collection we will examine is the ConcurrentBag and a very useful wrapper class called the BlockingCollection. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this informative whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentBag<T> – Thread-safe unordered collection. Unlike the other concurrent collections, the ConcurrentBag<T> has no non-concurrent counterpart in the .NET collections libraries.  Items can be added and removed from a bag just like any other collection, but unlike the other collections, the items are not maintained in any order.  This makes the bag handy for those cases when all you care about is that the data be consumed eventually, without regard for order of consumption or even fairness – that is, it’s possible new items could be consumed before older items given the right circumstances for a period of time. So why would you ever want a container that can be unfair?  Well, to look at it another way, you can use a ConcurrentQueue and get the fairness, but it comes at a cost in that the ordering rules and synchronization required to maintain that ordering can affect scalability a bit.  Thus sometimes the bag is great when you want the fastest way to get the next item to process, and don’t care what item it is or how long its been waiting. The way that the ConcurrentBag works is to take advantage of the new ThreadLocal<T> type (new in System.Threading for .NET 4.0) so that each thread using the bag has a list local to just that thread.  This means that adding or removing to a thread-local list requires very low synchronization.  The problem comes in where a thread goes to consume an item but it’s local list is empty.  In this case the bag performs “work-stealing” where it will rob an item from another thread that has items in its list.  This requires a higher level of synchronization which adds a bit of overhead to the take operation. So, as you can imagine, this makes the ConcurrentBag good for situations where each thread both produces and consumes items from the bag, but it would be less-than-idea in situations where some threads are dedicated producers and the other threads are dedicated consumers because the work-stealing synchronization would outweigh the thread-local optimization for a thread taking its own items. Like the other concurrent collections, there are some curiosities to keep in mind: IsEmpty(), Count, ToArray(), and GetEnumerator() lock collection Each of these needs to take a snapshot of whole bag to determine if empty, thus they tend to be more expensive and cause Add() and Take() operations to block. ToArray() and GetEnumerator() are static snapshots Because it is based on a snapshot, will not show subsequent updates after snapshot. Add() is lightweight Since adding to the thread-local list, there is very little overhead on Add. TryTake() is lightweight if items in thread-local list As long as items are in the thread-local list, TryTake() is very lightweight, much more so than ConcurrentStack() and ConcurrentQueue(), however if the local thread list is empty, it must steal work from another thread, which is more expensive. Remember, a bag is not ideal for all situations, it is mainly ideal for situations where a process consumes an item and either decomposes it into more items to be processed, or handles the item partially and places it back to be processed again until some point when it will complete.  The main point is that the bag works best when each thread both takes and adds items. For example, we could create a totally contrived example where perhaps we want to see the largest power of a number before it crosses a certain threshold.  Yes, obviously we could easily do this with a log function, but bare with me while I use this contrived example for simplicity. So let’s say we have a work function that will take a Tuple out of a bag, this Tuple will contain two ints.  The first int is the original number, and the second int is the last multiple of that number.  So we could load our bag with the initial values (let’s say we want to know the last multiple of each of 2, 3, 5, and 7 under 100. 1: var bag = new ConcurrentBag<Tuple<int, int>> 2: { 3: Tuple.Create(2, 1), 4: Tuple.Create(3, 1), 5: Tuple.Create(5, 1), 6: Tuple.Create(7, 1) 7: }; Then we can create a method that given the bag, will take out an item, apply the multiplier again, 1: public static void FindHighestPowerUnder(ConcurrentBag<Tuple<int,int>> bag, int threshold) 2: { 3: Tuple<int,int> pair; 4:  5: // while there are items to take, this will prefer local first, then steal if no local 6: while (bag.TryTake(out pair)) 7: { 8: // look at next power 9: var result = Math.Pow(pair.Item1, pair.Item2 + 1); 10:  11: if (result < threshold) 12: { 13: // if smaller than threshold bump power by 1 14: bag.Add(Tuple.Create(pair.Item1, pair.Item2 + 1)); 15: } 16: else 17: { 18: // otherwise, we're done 19: Console.WriteLine("Highest power of {0} under {3} is {0}^{1} = {2}.", 20: pair.Item1, pair.Item2, Math.Pow(pair.Item1, pair.Item2), threshold); 21: } 22: } 23: } Now that we have this, we can load up this method as an Action into our Tasks and run it: 1: // create array of tasks, start all, wait for all 2: var tasks = new[] 3: { 4: new Task(() => FindHighestPowerUnder(bag, 100)), 5: new Task(() => FindHighestPowerUnder(bag, 100)), 6: }; 7:  8: Array.ForEach(tasks, t => t.Start()); 9:  10: Task.WaitAll(tasks); Totally contrived, I know, but keep in mind the main point!  When you have a thread or task that operates on an item, and then puts it back for further consumption – or decomposes an item into further sub-items to be processed – you should consider a ConcurrentBag as the thread-local lists will allow for quick processing.  However, if you need ordering or if your processes are dedicated producers or consumers, this collection is not ideal.  As with anything, you should performance test as your mileage will vary depending on your situation! BlockingCollection<T> – A producers & consumers pattern collection The BlockingCollection<T> can be treated like a collection in its own right, but in reality it adds a producers and consumers paradigm to any collection that implements the interface IProducerConsumerCollection<T>.  If you don’t specify one at the time of construction, it will use a ConcurrentQueue<T> as its underlying store. If you don’t want to use the ConcurrentQueue, the ConcurrentStack and ConcurrentBag also implement the interface (though ConcurrentDictionary does not).  In addition, you are of course free to create your own implementation of the interface. So, for those who don’t remember the producers and consumers classical computer-science problem, the gist of it is that you have one (or more) processes that are creating items (producers) and one (or more) processes that are consuming these items (consumers).  Now, the crux of the problem is that there is a bin (queue) where the produced items are placed, and typically that bin has a limited size.  Thus if a producer creates an item, but there is no space to store it, it must wait until an item is consumed.  Also if a consumer goes to consume an item and none exists, it must wait until an item is produced. The BlockingCollection makes it trivial to implement any standard producers/consumers process set by providing that “bin” where the items can be produced into and consumed from with the appropriate blocking operations.  In addition, you can specify whether the bin should have a limited size or can be (theoretically) unbounded, and you can specify timeouts on the blocking operations. As far as your choice of “bin”, for the most part the ConcurrentQueue is the right choice because it is fairly light and maximizes fairness by ordering items so that they are consumed in the same order they are produced.  You can use the concurrent bag or stack, of course, but your ordering would be random-ish in the case of the former and LIFO in the case of the latter. So let’s look at some of the methods of note in BlockingCollection: BoundedCapacity returns capacity of the “bin” If the bin is unbounded, the capacity is int.MaxValue. Count returns an internally-kept count of items This makes it O(1), but if you modify underlying collection directly (not recommended) it is unreliable. CompleteAdding() is used to cut off further adds. This sets IsAddingCompleted and begins to wind down consumers once empty. IsAddingCompleted is true when producers are “done”. Once you are done producing, should complete the add process to alert consumers. IsCompleted is true when producers are “done” and “bin” is empty. Once you mark the producers done, and all items removed, this will be true. Add() is a blocking add to collection. If bin is full, will wait till space frees up Take() is a blocking remove from collection. If bin is empty, will wait until item is produced or adding is completed. GetConsumingEnumerable() is used to iterate and consume items. Unlike the standard enumerator, this one consumes the items instead of iteration. TryAdd() attempts add but does not block completely If adding would block, returns false instead, can specify TimeSpan to wait before stopping. TryTake() attempts to take but does not block completely Like TryAdd(), if taking would block, returns false instead, can specify TimeSpan to wait. Note the use of CompleteAdding() to signal the BlockingCollection that nothing else should be added.  This means that any attempts to TryAdd() or Add() after marked completed will throw an InvalidOperationException.  In addition, once adding is complete you can still continue to TryTake() and Take() until the bin is empty, and then Take() will throw the InvalidOperationException and TryTake() will return false. So let’s create a simple program to try this out.  Let’s say that you have one process that will be producing items, but a slower consumer process that handles them.  This gives us a chance to peek inside what happens when the bin is bounded (by default, the bin is NOT bounded). 1: var bin = new BlockingCollection<int>(5); Now, we create a method to produce items: 1: public static void ProduceItems(BlockingCollection<int> bin, int numToProduce) 2: { 3: for (int i = 0; i < numToProduce; i++) 4: { 5: // try for 10 ms to add an item 6: while (!bin.TryAdd(i, TimeSpan.FromMilliseconds(10))) 7: { 8: Console.WriteLine("Bin is full, retrying..."); 9: } 10: } 11:  12: // once done producing, call CompleteAdding() 13: Console.WriteLine("Adding is completed."); 14: bin.CompleteAdding(); 15: } And one to consume them: 1: public static void ConsumeItems(BlockingCollection<int> bin) 2: { 3: // This will only be true if CompleteAdding() was called AND the bin is empty. 4: while (!bin.IsCompleted) 5: { 6: int item; 7:  8: if (!bin.TryTake(out item, TimeSpan.FromMilliseconds(10))) 9: { 10: Console.WriteLine("Bin is empty, retrying..."); 11: } 12: else 13: { 14: Console.WriteLine("Consuming item {0}.", item); 15: Thread.Sleep(TimeSpan.FromMilliseconds(20)); 16: } 17: } 18: } Then we can fire them off: 1: // create one producer and two consumers 2: var tasks = new[] 3: { 4: new Task(() => ProduceItems(bin, 20)), 5: new Task(() => ConsumeItems(bin)), 6: new Task(() => ConsumeItems(bin)), 7: }; 8:  9: Array.ForEach(tasks, t => t.Start()); 10:  11: Task.WaitAll(tasks); Notice that the producer is faster than the consumer, thus it should be hitting a full bin often and displaying the message after it times out on TryAdd(). 1: Consuming item 0. 2: Consuming item 1. 3: Bin is full, retrying... 4: Bin is full, retrying... 5: Consuming item 3. 6: Consuming item 2. 7: Bin is full, retrying... 8: Consuming item 4. 9: Consuming item 5. 10: Bin is full, retrying... 11: Consuming item 6. 12: Consuming item 7. 13: Bin is full, retrying... 14: Consuming item 8. 15: Consuming item 9. 16: Bin is full, retrying... 17: Consuming item 10. 18: Consuming item 11. 19: Bin is full, retrying... 20: Consuming item 12. 21: Consuming item 13. 22: Bin is full, retrying... 23: Bin is full, retrying... 24: Consuming item 14. 25: Adding is completed. 26: Consuming item 15. 27: Consuming item 16. 28: Consuming item 17. 29: Consuming item 19. 30: Consuming item 18. Also notice that once CompleteAdding() is called and the bin is empty, the IsCompleted property returns true, and the consumers will exit. Summary The ConcurrentBag is an interesting collection that can be used to optimize concurrency scenarios where tasks or threads both produce and consume items.  In this way, it will choose to consume its own work if available, and then steal if not.  However, in situations where you want fair consumption or ordering, or in situations where the producers and consumers are distinct processes, the bag is not optimal. The BlockingCollection is a great wrapper around all of the concurrent queue, stack, and bag that allows you to add producer and consumer semantics easily including waiting when the bin is full or empty. That’s the end of my dive into the concurrent collections.  I’d also strongly recommend, once again, you read this excellent Microsoft white paper that goes into much greater detail on the efficiencies you can gain using these collections judiciously (here). Tweet Technorati Tags: C#,.NET,Concurrent Collections,Little Wonders

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  • What strategy do you use for package naming in Java projects and why?

    - by Tim Visher
    I thought about this awhile ago and it recently resurfaced as my shop is doing its first real Java web app. As an intro, I see two main package naming strategies. (To be clear, I'm not referring to the whole 'domain.company.project' part of this, I'm talking about the package convention beneath that.) Anyway, the package naming conventions that I see are as follows: Functional: Naming your packages according to their function architecturally rather than their identity according to the business domain. Another term for this might be naming according to 'layer'. So, you'd have a *.ui package and a *.domain package and a *.orm package. Your packages are horizontal slices rather than vertical. This is much more common than logical naming. In fact, I don't believe I've ever seen or heard of a project that does this. This of course makes me leery (sort of like thinking that you've come up with a solution to an NP problem) as I'm not terribly smart and I assume everyone must have great reasons for doing it the way they do. On the other hand, I'm not opposed to people just missing the elephant in the room and I've never heard a an actual argument for doing package naming this way. It just seems to be the de facto standard. Logical: Naming your packages according to their business domain identity and putting every class that has to do with that vertical slice of functionality into that package. I have never seen or heard of this, as I mentioned before, but it makes a ton of sense to me. I tend to approach systems vertically rather than horizontally. I want to go in and develop the Order Processing system, not the data access layer. Obviously, there's a good chance that I'll touch the data access layer in the development of that system, but the point is that I don't think of it that way. What this means, of course, is that when I receive a change order or want to implement some new feature, it'd be nice to not have to go fishing around in a bunch of packages in order to find all the related classes. Instead, I just look in the X package because what I'm doing has to do with X. From a development standpoint, I see it as a major win to have your packages document your business domain rather than your architecture. I feel like the domain is almost always the part of the system that's harder to grok where as the system's architecture, especially at this point, is almost becoming mundane in its implementation. The fact that I can come to a system with this type of naming convention and instantly from the naming of the packages know that it deals with orders, customers, enterprises, products, etc. seems pretty darn handy. It seems like this would allow you to take much better advantage of Java's access modifiers. This allows you to much more cleanly define interfaces into subsystems rather than into layers of the system. So if you have an orders subsystem that you want to be transparently persistent, you could in theory just never let anything else know that it's persistent by not having to create public interfaces to its persistence classes in the dao layer and instead packaging the dao class in with only the classes it deals with. Obviously, if you wanted to expose this functionality, you could provide an interface for it or make it public. It just seems like you lose a lot of this by having a vertical slice of your system's features split across multiple packages. I suppose one disadvantage that I can see is that it does make ripping out layers a little bit more difficult. Instead of just deleting or renaming a package and then dropping a new one in place with an alternate technology, you have to go in and change all of the classes in all of the packages. However, I don't see this is a big deal. It may be from a lack of experience, but I have to imagine that the amount of times you swap out technologies pales in comparison to the amount of times you go in and edit vertical feature slices within your system. So I guess the question then would go out to you, how do you name your packages and why? Please understand that I don't necessarily think that I've stumbled onto the golden goose or something here. I'm pretty new to all this with mostly academic experience. However, I can't spot the holes in my reasoning so I'm hoping you all can so that I can move on. Thanks in advance!

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  • MERGE Bug with Filtered Indexes

    - by Paul White
    A MERGE statement can fail, and incorrectly report a unique key violation when: The target table uses a unique filtered index; and No key column of the filtered index is updated; and A column from the filtering condition is updated; and Transient key violations are possible Example Tables Say we have two tables, one that is the target of a MERGE statement, and another that contains updates to be applied to the target.  The target table contains three columns, an integer primary key, a single character alternate key, and a status code column.  A filtered unique index exists on the alternate key, but is only enforced where the status code is ‘a’: CREATE TABLE #Target ( pk integer NOT NULL, ak character(1) NOT NULL, status_code character(1) NOT NULL,   PRIMARY KEY (pk) );   CREATE UNIQUE INDEX uq1 ON #Target (ak) INCLUDE (status_code) WHERE status_code = 'a'; The changes table contains just an integer primary key (to identify the target row to change) and the new status code: CREATE TABLE #Changes ( pk integer NOT NULL, status_code character(1) NOT NULL,   PRIMARY KEY (pk) ); Sample Data The sample data for the example is: INSERT #Target (pk, ak, status_code) VALUES (1, 'A', 'a'), (2, 'B', 'a'), (3, 'C', 'a'), (4, 'A', 'd');   INSERT #Changes (pk, status_code) VALUES (1, 'd'), (4, 'a');          Target                     Changes +-----------------------+    +------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦ ¦  1 ¦ A  ¦ a           ¦    ¦  1 ¦ d           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+ ¦  4 ¦ A  ¦ d           ¦ +-----------------------+ The target table’s alternate key (ak) column is unique, for rows where status_code = ‘a’.  Applying the changes to the target will change row 1 from status ‘a’ to status ‘d’, and row 4 from status ‘d’ to status ‘a’.  The result of applying all the changes will still satisfy the filtered unique index, because the ‘A’ in row 1 will be deleted from the index and the ‘A’ in row 4 will be added. Merge Test One Let’s now execute a MERGE statement to apply the changes: MERGE #Target AS t USING #Changes AS c ON c.pk = t.pk WHEN MATCHED AND c.status_code <> t.status_code THEN UPDATE SET status_code = c.status_code; The MERGE changes the two target rows as expected.  The updated target table now contains: +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦ ¦  1 ¦ A  ¦ d           ¦ <—changed from ‘a’ ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ a           ¦ <—changed from ‘d’ +-----------------------+ Merge Test Two Now let’s repopulate the changes table to reverse the updates we just performed: TRUNCATE TABLE #Changes;   INSERT #Changes (pk, status_code) VALUES (1, 'a'), (4, 'd'); This will change row 1 back to status ‘a’ and row 4 back to status ‘d’.  As a reminder, the current state of the tables is:          Target                        Changes +-----------------------+    +------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦ ¦  1 ¦ A  ¦ d           ¦    ¦  1 ¦ a           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ d           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+ ¦  4 ¦ A  ¦ a           ¦ +-----------------------+ We execute the same MERGE statement: MERGE #Target AS t USING #Changes AS c ON c.pk = t.pk WHEN MATCHED AND c.status_code <> t.status_code THEN UPDATE SET status_code = c.status_code; However this time we receive the following message: Msg 2601, Level 14, State 1, Line 1 Cannot insert duplicate key row in object 'dbo.#Target' with unique index 'uq1'. The duplicate key value is (A). The statement has been terminated. Applying the changes using UPDATE Let’s now rewrite the MERGE to use UPDATE instead: UPDATE t SET status_code = c.status_code FROM #Target AS t JOIN #Changes AS c ON t.pk = c.pk WHERE c.status_code <> t.status_code; This query succeeds where the MERGE failed.  The two rows are updated as expected: +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦ ¦  1 ¦ A  ¦ a           ¦ <—changed back to ‘a’ ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ d           ¦ <—changed back to ‘d’ +-----------------------+ What went wrong with the MERGE? In this test, the MERGE query execution happens to apply the changes in the order of the ‘pk’ column. In test one, this was not a problem: row 1 is removed from the unique filtered index by changing status_code from ‘a’ to ‘d’ before row 4 is added.  At no point does the table contain two rows where ak = ‘A’ and status_code = ‘a’. In test two, however, the first change was to change row 1 from status ‘d’ to status ‘a’.  This change means there would be two rows in the filtered unique index where ak = ‘A’ (both row 1 and row 4 meet the index filtering criteria ‘status_code = a’). The storage engine does not allow the query processor to violate a unique key (unless IGNORE_DUP_KEY is ON, but that is a different story, and doesn’t apply to MERGE in any case).  This strict rule applies regardless of the fact that if all changes were applied, there would be no unique key violation (row 4 would eventually be changed from ‘a’ to ‘d’, removing it from the filtered unique index, and resolving the key violation). Why it went wrong The query optimizer usually detects when this sort of temporary uniqueness violation could occur, and builds a plan that avoids the issue.  I wrote about this a couple of years ago in my post Beware Sneaky Reads with Unique Indexes (you can read more about the details on pages 495-497 of Microsoft SQL Server 2008 Internals or in Craig Freedman’s blog post on maintaining unique indexes).  To summarize though, the optimizer introduces Split, Filter, Sort, and Collapse operators into the query plan to: Split each row update into delete followed by an inserts Filter out rows that would not change the index (due to the filter on the index, or a non-updating update) Sort the resulting stream by index key, with deletes before inserts Collapse delete/insert pairs on the same index key back into an update The effect of all this is that only net changes are applied to an index (as one or more insert, update, and/or delete operations).  In this case, the net effect is a single update of the filtered unique index: changing the row for ak = ‘A’ from pk = 4 to pk = 1.  In case that is less than 100% clear, let’s look at the operation in test two again:          Target                     Changes                   Result +-----------------------+    +------------------+    +-----------------------+ ¦ pk ¦ ak ¦ status_code ¦    ¦ pk ¦ status_code ¦    ¦ pk ¦ ak ¦ status_code ¦ ¦----+----+-------------¦    ¦----+-------------¦    ¦----+----+-------------¦ ¦  1 ¦ A  ¦ d           ¦    ¦  1 ¦ d           ¦    ¦  1 ¦ A  ¦ a           ¦ ¦  2 ¦ B  ¦ a           ¦    ¦  4 ¦ a           ¦    ¦  2 ¦ B  ¦ a           ¦ ¦  3 ¦ C  ¦ a           ¦    +------------------+    ¦  3 ¦ C  ¦ a           ¦ ¦  4 ¦ A  ¦ a           ¦                            ¦  4 ¦ A  ¦ d           ¦ +-----------------------+                            +-----------------------+ From the filtered index’s point of view (filtered for status_code = ‘a’ and shown in nonclustered index key order) the overall effect of the query is:   Before           After +---------+    +---------+ ¦ pk ¦ ak ¦    ¦ pk ¦ ak ¦ ¦----+----¦    ¦----+----¦ ¦  4 ¦ A  ¦    ¦  1 ¦ A  ¦ ¦  2 ¦ B  ¦    ¦  2 ¦ B  ¦ ¦  3 ¦ C  ¦    ¦  3 ¦ C  ¦ +---------+    +---------+ The single net change there is a change of pk from 4 to 1 for the nonclustered index entry ak = ‘A’.  This is the magic performed by the split, sort, and collapse.  Notice in particular how the original changes to the index key (on the ‘ak’ column) have been transformed into an update of a non-key column (pk is included in the nonclustered index).  By not updating any nonclustered index keys, we are guaranteed to avoid transient key violations. The Execution Plans The estimated MERGE execution plan that produces the incorrect key-violation error looks like this (click to enlarge in a new window): The successful UPDATE execution plan is (click to enlarge in a new window): The MERGE execution plan is a narrow (per-row) update.  The single Clustered Index Merge operator maintains both the clustered index and the filtered nonclustered index.  The UPDATE plan is a wide (per-index) update.  The clustered index is maintained first, then the Split, Filter, Sort, Collapse sequence is applied before the nonclustered index is separately maintained. There is always a wide update plan for any query that modifies the database. The narrow form is a performance optimization where the number of rows is expected to be relatively small, and is not available for all operations.  One of the operations that should disallow a narrow plan is maintaining a unique index where intermediate key violations could occur. Workarounds The MERGE can be made to work (producing a wide update plan with split, sort, and collapse) by: Adding all columns referenced in the filtered index’s WHERE clause to the index key (INCLUDE is not sufficient); or Executing the query with trace flag 8790 set e.g. OPTION (QUERYTRACEON 8790). Undocumented trace flag 8790 forces a wide update plan for any data-changing query (remember that a wide update plan is always possible).  Either change will produce a successfully-executing wide update plan for the MERGE that failed previously. Conclusion The optimizer fails to spot the possibility of transient unique key violations with MERGE under the conditions listed at the start of this post.  It incorrectly chooses a narrow plan for the MERGE, which cannot provide the protection of a split/sort/collapse sequence for the nonclustered index maintenance. The MERGE plan may fail at execution time depending on the order in which rows are processed, and the distribution of data in the database.  Worse, a previously solid MERGE query may suddenly start to fail unpredictably if a filtered unique index is added to the merge target table at any point. Connect bug filed here Tests performed on SQL Server 2012 SP1 CUI (build 11.0.3321) x64 Developer Edition © 2012 Paul White – All Rights Reserved Twitter: @SQL_Kiwi Email: [email protected]

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  • Abstracting functionality

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/22/abstracting-functionality.aspxWhat is more important than data? Functionality. Yes, I strongly believe we should switch to a functionality over data mindset in programming. Or actually switch back to it. Focus on functionality Functionality once was at the core of software development. Back when algorithms were the first thing you heard about in CS classes. Sure, data structures, too, were important - but always from the point of view of algorithms. (Niklaus Wirth gave one of his books the title “Algorithms + Data Structures” instead of “Data Structures + Algorithms” for a reason.) The reason for the focus on functionality? Firstly, because software was and is about doing stuff. Secondly because sufficient performance was hard to achieve, and only thirdly memory efficiency. But then hardware became more powerful. That gave rise to a new mindset: object orientation. And with it functionality was devalued. Data took over its place as the most important aspect. Now discussions revolved around structures motivated by data relationships. (John Beidler gave his book the title “Data Structures and Algorithms: An Object Oriented Approach” instead of the other way around for a reason.) Sure, this data could be embellished with functionality. But nevertheless functionality was second. When you look at (domain) object models what you mostly find is (domain) data object models. The common object oriented approach is: data aka structure over functionality. This is true even for the most modern modeling approaches like Domain Driven Design. Look at the literature and what you find is recommendations on how to get data structures right: aggregates, entities, value objects. I´m not saying this is what object orientation was invented for. But I´m saying that´s what I happen to see across many teams now some 25 years after object orientation became mainstream through C++, Delphi, and Java. But why should we switch back? Because software development cannot become truly agile with a data focus. The reason for that lies in what customers need first: functionality, behavior, operations. To be clear, that´s not why software is built. The purpose of software is to be more efficient than the alternative. Money mainly is spent to get a certain level of quality (e.g. performance, scalability, security etc.). But without functionality being present, there is nothing to work on the quality of. What customers want is functionality of a certain quality. ASAP. And tomorrow new functionality needs to be added, existing functionality needs to be changed, and quality needs to be increased. No customer ever wanted data or structures. Of course data should be processed. Data is there, data gets generated, transformed, stored. But how the data is structured for this to happen efficiently is of no concern to the customer. Ask a customer (or user) whether she likes the data structured this way or that way. She´ll say, “I don´t care.” But ask a customer (or user) whether he likes the functionality and its quality this way or that way. He´ll say, “I like it” (or “I don´t like it”). Build software incrementally From this very natural focus of customers and users on functionality and its quality follows we should develop software incrementally. That´s what Agility is about. Deliver small increments quickly and often to get frequent feedback. That way less waste is produced, and learning can take place much easier (on the side of the customer as well as on the side of developers). An increment is some added functionality or quality of functionality.[1] So as it turns out, Agility is about functionality over whatever. But software developers’ thinking is still stuck in the object oriented mindset of whatever over functionality. Bummer. I guess that (at least partly) explains why Agility always hits a glass ceiling in projects. It´s a clash of mindsets, of cultures. Driving software development by demanding small increases in functionality runs against thinking about software as growing (data) structures sprinkled with functionality. (Excuse me, if this sounds a bit broad-brush. But you get my point.) The need for abstraction In the end there need to be data structures. Of course. Small and large ones. The phrase functionality over data does not deny that. It´s not functionality instead of data or something. It´s just over, i.e. functionality should be thought of first. It´s a tad more important. It´s what the customer wants. That´s why we need a way to design functionality. Small and large. We need to be able to think about functionality before implementing it. We need to be able to reason about it among team members. We need to be able to communicate our mental models of functionality not just by speaking about them, but also on paper. Otherwise reasoning about it does not scale. We learned thinking about functionality in the small using flow charts, Nassi-Shneiderman diagrams, pseudo code, or UML sequence diagrams. That´s nice and well. But it does not scale. You can use these tools to describe manageable algorithms. But it does not work for the functionality triggered by pressing the “1-Click Order” on an amazon product page for example. There are several reasons for that, I´d say. Firstly, the level of abstraction over code is negligible. It´s essentially non-existent. Drawing a flow chart or writing pseudo code or writing actual code is very, very much alike. All these tools are about control flow like code is.[2] In addition all tools are computationally complete. They are about logic which is expressions and especially control statements. Whatever you code in Java you can fully (!) describe using a flow chart. And then there is no data. They are about control flow and leave out the data altogether. Thus data mostly is assumed to be global. That´s shooting yourself in the foot, as I hope you agree. Even if it´s functionality over data that does not mean “don´t think about data”. Right to the contrary! Functionality only makes sense with regard to data. So data needs to be in the picture right from the start - but it must not dominate the thinking. The above tools fail on this. Bottom line: So far we´re unable to reason in a scalable and abstract manner about functionality. That´s why programmers are so driven to start coding once they are presented with a problem. Programming languages are the only tool they´ve learned to use to reason about functional solutions. Or, well, there might be exceptions. Mathematical notation and SQL may have come to your mind already. Indeed they are tools on a higher level of abstraction than flow charts etc. That´s because they are declarative and not computationally complete. They leave out details - in order to deliver higher efficiency in devising overall solutions. We can easily reason about functionality using mathematics and SQL. That´s great. Except for that they are domain specific languages. They are not general purpose. (And they don´t scale either, I´d say.) Bummer. So to be more precise we need a scalable general purpose tool on a higher than code level of abstraction not neglecting data. Enter: Flow Design. Abstracting functionality using data flows I believe the solution to the problem of abstracting functionality lies in switching from control flow to data flow. Data flow very naturally is not about logic details anymore. There are no expressions and no control statements anymore. There are not even statements anymore. Data flow is declarative by nature. With data flow we get rid of all the limiting traits of former approaches to modeling functionality. In addition, nomen est omen, data flows include data in the functionality picture. With data flows, data is visibly flowing from processing step to processing step. Control is not flowing. Control is wherever it´s needed to process data coming in. That´s a crucial difference and needs some rewiring in your head to be fully appreciated.[2] Since data flows are declarative they are not the right tool to describe algorithms, though, I´d say. With them you don´t design functionality on a low level. During design data flow processing steps are black boxes. They get fleshed out during coding. Data flow design thus is more coarse grained than flow chart design. It starts on a higher level of abstraction - but then is not limited. By nesting data flows indefinitely you can design functionality of any size, without losing sight of your data. Data flows scale very well during design. They can be used on any level of granularity. And they can easily be depicted. Communicating designs using data flows is easy and scales well, too. The result of functional design using data flows is not algorithms (too low level), but processes. Think of data flows as descriptions of industrial production lines. Data as material runs through a number of processing steps to be analyzed, enhances, transformed. On the top level of a data flow design might be just one processing step, e.g. “execute 1-click order”. But below that are arbitrary levels of flows with smaller and smaller steps. That´s not layering as in “layered architecture”, though. Rather it´s a stratified design à la Abelson/Sussman. Refining data flows is not your grandpa´s functional decomposition. That was rooted in control flows. Refining data flows does not suffer from the limits of functional decomposition against which object orientation was supposed to be an antidote. Summary I´ve been working exclusively with data flows for functional design for the past 4 years. It has changed my life as a programmer. What once was difficult is now easy. And, no, I´m not using Clojure or F#. And I´m not a async/parallel execution buff. Designing the functionality of increments using data flows works great with teams. It produces design documentation which can easily be translated into code - in which then the smallest data flow processing steps have to be fleshed out - which is comparatively easy. Using a systematic translation approach code can mirror the data flow design. That way later on the design can easily be reproduced from the code if need be. And finally, data flow designs play well with object orientation. They are a great starting point for class design. But that´s a story for another day. To me data flow design simply is one of the missing links of systematic lightweight software design. There are also other artifacts software development can produce to get feedback, e.g. process descriptions, test cases. But customers can be delighted more easily with code based increments in functionality. ? No, I´m not talking about the endless possibilities this opens for parallel processing. Data flows are useful independently of multi-core processors and Actor-based designs. That´s my whole point here. Data flows are good for reasoning and evolvability. So forget about any special frameworks you might need to reap benefits from data flows. None are necessary. Translating data flow designs even into plain of Java is possible. ?

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  • Inside the Concurrent Collections: ConcurrentDictionary

    - by Simon Cooper
    Using locks to implement a thread-safe collection is rather like using a sledgehammer - unsubtle, easy to understand, and tends to make any other tool redundant. Unlike the previous two collections I looked at, ConcurrentStack and ConcurrentQueue, ConcurrentDictionary uses locks quite heavily. However, it is careful to wield locks only where necessary to ensure that concurrency is maximised. This will, by necessity, be a higher-level look than my other posts in this series, as there is quite a lot of code and logic in ConcurrentDictionary. Therefore, I do recommend that you have ConcurrentDictionary open in a decompiler to have a look at all the details that I skip over. The problem with locks There's several things to bear in mind when using locks, as encapsulated by the lock keyword in C# and the System.Threading.Monitor class in .NET (if you're unsure as to what lock does in C#, I briefly covered it in my first post in the series): Locks block threads The most obvious problem is that threads waiting on a lock can't do any work at all. No preparatory work, no 'optimistic' work like in ConcurrentQueue and ConcurrentStack, nothing. It sits there, waiting to be unblocked. This is bad if you're trying to maximise concurrency. Locks are slow Whereas most of the methods on the Interlocked class can be compiled down to a single CPU instruction, ensuring atomicity at the hardware level, taking out a lock requires some heavy lifting by the CLR and the operating system. There's quite a bit of work required to take out a lock, block other threads, and wake them up again. If locks are used heavily, this impacts performance. Deadlocks When using locks there's always the possibility of a deadlock - two threads, each holding a lock, each trying to aquire the other's lock. Fortunately, this can be avoided with careful programming and structured lock-taking, as we'll see. So, it's important to minimise where locks are used to maximise the concurrency and performance of the collection. Implementation As you might expect, ConcurrentDictionary is similar in basic implementation to the non-concurrent Dictionary, which I studied in a previous post. I'll be using some concepts introduced there, so I recommend you have a quick read of it. So, if you were implementing a thread-safe dictionary, what would you do? The naive implementation is to simply have a single lock around all methods accessing the dictionary. This would work, but doesn't allow much concurrency. Fortunately, the bucketing used by Dictionary allows a simple but effective improvement to this - one lock per bucket. This allows different threads modifying different buckets to do so in parallel. Any thread making changes to the contents of a bucket takes the lock for that bucket, ensuring those changes are thread-safe. The method that maps each bucket to a lock is the GetBucketAndLockNo method: private void GetBucketAndLockNo( int hashcode, out int bucketNo, out int lockNo, int bucketCount) { // the bucket number is the hashcode (without the initial sign bit) // modulo the number of buckets bucketNo = (hashcode & 0x7fffffff) % bucketCount; // and the lock number is the bucket number modulo the number of locks lockNo = bucketNo % m_locks.Length; } However, this does require some changes to how the buckets are implemented. The 'implicit' linked list within a single backing array used by the non-concurrent Dictionary adds a dependency between separate buckets, as every bucket uses the same backing array. Instead, ConcurrentDictionary uses a strict linked list on each bucket: This ensures that each bucket is entirely separate from all other buckets; adding or removing an item from a bucket is independent to any changes to other buckets. Modifying the dictionary All the operations on the dictionary follow the same basic pattern: void AlterBucket(TKey key, ...) { int bucketNo, lockNo; 1: GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, m_buckets.Length); 2: lock (m_locks[lockNo]) { 3: Node headNode = m_buckets[bucketNo]; 4: Mutate the node linked list as appropriate } } For example, when adding another entry to the dictionary, you would iterate through the linked list to check whether the key exists already, and add the new entry as the head node. When removing items, you would find the entry to remove (if it exists), and remove the node from the linked list. Adding, updating, and removing items all follow this pattern. Performance issues There is a problem we have to address at this point. If the number of buckets in the dictionary is fixed in the constructor, then the performance will degrade from O(1) to O(n) when a large number of items are added to the dictionary. As more and more items get added to the linked lists in each bucket, the lookup operations will spend most of their time traversing a linear linked list. To fix this, the buckets array has to be resized once the number of items in each bucket has gone over a certain limit. (In ConcurrentDictionary this limit is when the size of the largest bucket is greater than the number of buckets for each lock. This check is done at the end of the TryAddInternal method.) Resizing the bucket array and re-hashing everything affects every bucket in the collection. Therefore, this operation needs to take out every lock in the collection. Taking out mutiple locks at once inevitably summons the spectre of the deadlock; two threads each hold a lock, and each trying to acquire the other lock. How can we eliminate this? Simple - ensure that threads never try to 'swap' locks in this fashion. When taking out multiple locks, always take them out in the same order, and always take out all the locks you need before starting to release them. In ConcurrentDictionary, this is controlled by the AcquireLocks, AcquireAllLocks and ReleaseLocks methods. Locks are always taken out and released in the order they are in the m_locks array, and locks are all released right at the end of the method in a finally block. At this point, it's worth pointing out that the locks array is never re-assigned, even when the buckets array is increased in size. The number of locks is fixed in the constructor by the concurrencyLevel parameter. This simplifies programming the locks; you don't have to check if the locks array has changed or been re-assigned before taking out a lock object. And you can be sure that when a thread takes out a lock, another thread isn't going to re-assign the lock array. This would create a new series of lock objects, thus allowing another thread to ignore the existing locks (and any threads controlling them), breaking thread-safety. Consequences of growing the array Just because we're using locks doesn't mean that race conditions aren't a problem. We can see this by looking at the GrowTable method. The operation of this method can be boiled down to: private void GrowTable(Node[] buckets) { try { 1: Acquire first lock in the locks array // this causes any other thread trying to take out // all the locks to block because the first lock in the array // is always the one taken out first // check if another thread has already resized the buckets array // while we were waiting to acquire the first lock 2: if (buckets != m_buckets) return; 3: Calculate the new size of the backing array 4: Node[] array = new array[size]; 5: Acquire all the remaining locks 6: Re-hash the contents of the existing buckets into array 7: m_buckets = array; } finally { 8: Release all locks } } As you can see, there's already a check for a race condition at step 2, for the case when the GrowTable method is called twice in quick succession on two separate threads. One will successfully resize the buckets array (blocking the second in the meantime), when the second thread is unblocked it'll see that the array has already been resized & exit without doing anything. There is another case we need to consider; looking back at the AlterBucket method above, consider the following situation: Thread 1 calls AlterBucket; step 1 is executed to get the bucket and lock numbers. Thread 2 calls GrowTable and executes steps 1-5; thread 1 is blocked when it tries to take out the lock in step 2. Thread 2 re-hashes everything, re-assigns the buckets array, and releases all the locks (steps 6-8). Thread 1 is unblocked and continues executing, but the calculated bucket and lock numbers are no longer valid. Between calculating the correct bucket and lock number and taking out the lock, another thread has changed where everything is. Not exactly thread-safe. Well, a similar problem was solved in ConcurrentStack and ConcurrentQueue by storing a local copy of the state, doing the necessary calculations, then checking if that state is still valid. We can use a similar idea here: void AlterBucket(TKey key, ...) { while (true) { Node[] buckets = m_buckets; int bucketNo, lockNo; GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, buckets.Length); lock (m_locks[lockNo]) { // if the state has changed, go back to the start if (buckets != m_buckets) continue; Node headNode = m_buckets[bucketNo]; Mutate the node linked list as appropriate } break; } } TryGetValue and GetEnumerator And so, finally, we get onto TryGetValue and GetEnumerator. I've left these to the end because, well, they don't actually use any locks. How can this be? Whenever you change a bucket, you need to take out the corresponding lock, yes? Indeed you do. However, it is important to note that TryGetValue and GetEnumerator don't actually change anything. Just as immutable objects are, by definition, thread-safe, read-only operations don't need to take out a lock because they don't change anything. All lockless methods can happily iterate through the buckets and linked lists without worrying about locking anything. However, this does put restrictions on how the other methods operate. Because there could be another thread in the middle of reading the dictionary at any time (even if a lock is taken out), the dictionary has to be in a valid state at all times. Every change to state has to be made visible to other threads in a single atomic operation (all relevant variables are marked volatile to help with this). This restriction ensures that whatever the reading threads are doing, they never read the dictionary in an invalid state (eg items that should be in the collection temporarily removed from the linked list, or reading a node that has had it's key & value removed before the node itself has been removed from the linked list). Fortunately, all the operations needed to change the dictionary can be done in that way. Bucket resizes are made visible when the new array is assigned back to the m_buckets variable. Any additions or modifications to a node are done by creating a new node, then splicing it into the existing list using a single variable assignment. Node removals are simply done by re-assigning the node's m_next pointer. Because the dictionary can be changed by another thread during execution of the lockless methods, the GetEnumerator method is liable to return dirty reads - changes made to the dictionary after GetEnumerator was called, but before the enumeration got to that point in the dictionary. It's worth listing at this point which methods are lockless, and which take out all the locks in the dictionary to ensure they get a consistent view of the dictionary: Lockless: TryGetValue GetEnumerator The indexer getter ContainsKey Takes out every lock (lockfull?): Count IsEmpty Keys Values CopyTo ToArray Concurrent principles That covers the overall implementation of ConcurrentDictionary. I haven't even begun to scratch the surface of this sophisticated collection. That I leave to you. However, we've looked at enough to be able to extract some useful principles for concurrent programming: Partitioning When using locks, the work is partitioned into independant chunks, each with its own lock. Each partition can then be modified concurrently to other partitions. Ordered lock-taking When a method does need to control the entire collection, locks are taken and released in a fixed order to prevent deadlocks. Lockless reads Read operations that don't care about dirty reads don't take out any lock; the rest of the collection is implemented so that any reading thread always has a consistent view of the collection. That leads us to the final collection in this little series - ConcurrentBag. Lacking a non-concurrent analogy, it is quite different to any other collection in the class libraries. Prepare your thinking hats!

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