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  • Mysql Database Question about Large Columns

    - by murat
    Hi, I have a table that has 100.000 rows, and soon it will be doubled. The size of the database is currently 5 gb and most of them goes to one particular column, which is a text column for PDF files. We expect to have 20-30 GB or maybe 50 gb database after couple of month and this system will be used frequently. I have couple of questions regarding with this setup 1-) We are using innodb on every table, including users table etc. Is it better to use myisam on this table, where we store text version of the PDF files? (from memory usage /performance perspective) 2-) We use Sphinx for searching, however the data must be retrieved for highlighting. Highlighting is done via sphinx API but still we need to retrieve 10 rows in order to send it to Sphinx again. This 10 rows may allocate 50 mb memory, which is quite large. So I am planning to split these PDF files into chunks of 5 pages in the database, so these 100.000 rows will be around 3-4 million rows and couple of month later, instead of having 300.000-350.000 rows, we'll have 10 million rows to store text version of these PDF files. However, we will retrieve less pages, so again instead of retrieving 400 pages to send Sphinx for highlighting, we can retrieve 5 pages and it will have a big impact on the performance. Currently, when we search a term and retrieve PDF files that have more than 100 pages, the execution time is 0.3-0.35 seconds, however if we retrieve PDF files that have less than 5 pages, the execution time reduces to 0.06 seconds, and it also uses less memory. Do you think, this is a good trade-off? We will have million of rows instead of having 100k-200k rows but it will save memory and improve the performance. Is it a good approach to solve this problem and do you have any ideas how to overcome this problem? The text version of the data is used only for indexing and highlighting. So, we are very flexible. Thanks,

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  • Atomic int writes on file

    - by Waneck
    Hello! I'm writing an application that will have to be able to handle many concurrent accesses to it, either by threads as by processes. So no mutex'es or locks should be applied to this. To make the use of locks go down to a minimum, I'm designing for the file to be "append-only", so all data is first appended to disk, and then the address pointing to the info it has updated, is changed to refer to the new one. So I will need to implement a small lock system only to change this one int so it refers to the new address. How is the best way to do it? I was thinking about maybe putting a flag before the address, that when it's set, the readers will use a spin lock until it's released. But I'm afraid that it isn't at all atomic, is it? e.g. a reader reads the flag, and it is unset on the same time, a writer writes the flag and changes the value of the int the reader may read an inconsistent value! I'm looking for locking techniques but all I find is either for thread locking techniques, or to lock an entire file, not fields. Is it not possible to do this? How do append-only databases handle this? Thanks! Cauê

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  • Why is there no autorelease pool when I do performSelectorInBackground: ?

    - by Thanks
    I am calling a method that goes in a background thread: [self performSelectorInBackground:@selector(loadViewControllerWithIndex:) withObject:[NSNumber numberWithInt:viewControllerIndex]]; then, I have this method implementation that gets called by the selector: - (void) loadViewControllerWithIndex:(NSNumber *)indexNumberObj { NSAutoreleasePool *arPool = [[NSAutoreleasePool alloc] init]; NSInteger vcIndex = [indexNumberObj intValue]; Class c; UIViewController *controller = [viewControllers objectAtIndex:vcIndex]; switch (vcIndex) { case 0: c = [MyFirstViewController class]; break; case 1: c = [MySecondViewController class]; break; default: NSLog(@"unknown index for loading view controller: %d", vcIndex); // error break; } if ((NSNull *)controller == [NSNull null]) { controller = [[c alloc] initWithNib]; [viewControllers replaceObjectAtIndex:vcIndex withObject:controller]; [controller release]; } if (controller.view.superview == nil) { UIView *placeholderView = [viewControllerPlaceholderViews objectAtIndex:vcIndex]; [placeholderView addSubview:controller.view]; } [arPool release]; } Althoug I do create an autorelease pool there for that thread, I always get this error: 2009-05-30 12:03:09.910 Demo[1827:3f03] *** _NSAutoreleaseNoPool(): Object 0x523e50 of class NSCFNumber autoreleased with no pool in place - just leaking Stack: (0x95c83f0f 0x95b90442 0x28d3 0x2d42 0x95b96e0d 0x95b969b4 0x93a00155 0x93a00012) If I take away the autorelease pool, I get a whole bunch of messages like these. I also tried to create an autorelease pool around the call of the performSelectorInBackground:, but that doesn't help. I suspect the parameter, but I don't know why the compiler complains about an NSCFNumber. Am I missing something? My Instance variables are all "nonatomic". Can that be a problem? UPDATE: I may also suspect that some variable has been added to an autorelease pool of the main thread (maybe an ivar), and now it trys to release that one inside the wrong autorelease pool? If so, how could I fix that? (damn, this threading stuff is complex ;) )

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  • Prevent comment form re-submission

    - by Rob
    I'm got a comment form for an article and i'd to prevent re-submission. I notice that Worpdress handles this very well (going back doesn't cause the browser to request a form re-submission), but I can't figure out how they do it, even though our methods are very similar. My Script User visits mydomain.com/article/1/article_title.html Fills in a form which posts to mydomain.com/addnewcomment/1.html I then do a 302 redirect back to mydomain.com/article/1/article_title.html Now if I press back from this position it doesn't request a redirect. However, if I go to another page e.g. mydomain.com/tag/1/my_tag.html and press back it does resubmit the form. Obviously I want to prevent this. What Wordpress does User visits mydomain.com/?p=1 Fills in a form which posts to mydomain.com/wp-comments-post.php This then does a 302 redirect back to mydomain.com/?p=1 Pressing back or visiting another page and pressing back doesn't cause a re-submission. I've had a look through the WP code but I can't see how they manage this. Obviously it's something i'd like to achieve. Does anyone have any thoughts on where I may be going wrong? (I'm only using Wordpress as an example to prove that it's possible, obviously i'm not trying to exactly duplicate WP, that would be pointless)

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  • Calculate rotation between two Vector2s around a pivot

    - by Nick
    Hello all. After a good long Sunday google I am going to have to hang my head in shame and ask the question... What I have is a pivot vector2, a "Previous" vector2 and a "Current" vector2. I would like to be able to calculate the rotation in radians between them. A slight complication is the fact that the pivot may moved between previous and current but ill deal with the offsetting as a separate issue if you don't have the time to bring that into the fold. To clarify, an object which has two vectors, a pivot and a base ... the pivot sitting in the centre and the base at the bottom is rotated around an external pivot. I need to work out the rotation of the object itself around its centre using the two mentioned vectors. Very big thanks to anyone that can help. Background to problem I have a game where an object is rotated around an external pivot. By using using two points (one in the centre, one at the base of the object) I am wanting to to work out the rotation that needs to be applied to the objects sprite around its centre to conform to the larger rotation that has been applied.

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  • Web page database query optimization

    - by morpheous
    I am putting together a web page which is quite 'expensive' in terms of database hits. I don't want to start optimizing at this stage - though with me trying to hit a deadline, I may end up not optimizing at all. Currently the page requires 18 (that's right eighteen) hits to the db. I am already using joins, and some of the queries are UNIONed to minimize the trips to the db. My local dev machine can handle this (page is not slow) however, I feel if I release this into the wild, the number of queries will quickly overwhelm my database (MySQL). I could always use memcache or something similar, but I would much rather continue with my other dev work that needs to be completed before the deadline - at least retrieving the page works - its simply a matter of optimization now (if required). My question therefore is - is 18 db queries for a single page retrieval completely outrageous - (i.e. I should put everything on hold and optimize the hell of the retrieval logic), or shall I continue as normal, meet the deadline and release on schedule and see what happens? [Edit] Just to clarify, I have already done the 'obvious' things like using (single and composite) indexes for fields used in the queries. What I haven't yet done is to run a query analyzer to see if my indexes etc are optimal.

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  • Lazy Sequences that "Look Ahead" for Project Euler Problem 14

    - by ivar
    I'm trying to solve Project Euler Problem 14 in a lazy way. Unfortunately, I may be trying to do the impossible: create a lazy sequence that is both lazy, yet also somehow 'looks ahead' for values it hasn't computed yet. The non-lazy version I wrote to test correctness was: (defn chain-length [num] (loop [len 1 n num] (cond (= n 1) len (odd? n) (recur (inc len) (+ 1 (* 3 n))) true (recur (inc len) (/ n 2))))) Which works, but is really slow. Of course I could memoize that: (def memoized-chain (memoize (fn [n] (cond (= n 1) 1 (odd? n) (+ 1 (memoized-chain (+ 1 (* 3 n)))) true (+ 1 (memoized-chain (/ n 2))))))) However, what I really wanted to do was scratch my itch for understanding the limits of lazy sequences, and write a function like this: (def lazy-chain (letfn [(chain [n] (lazy-seq (cons (if (odd? n) (+ 1 (nth lazy-chain (dec (+ 1 (* 3 n))))) (+ 1 (nth lazy-chain (dec (/ n 2))))) (chain (+ n 1)))))] (chain 1))) Pulling elements from this will cause a stack overflow for n2, which is understandable if you think about why it needs to look 'into the future' at n=3 to know the value of the tenth element in the lazy list because (+ 1 (* 3 n)) = 10. Since lazy lists have much less overhead than memoization, I would like to know if this kind of thing is possible somehow via even more delayed evaluation or queuing?

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  • How to solve the problem of not being informed of successful payments by the 3rd party system used b

    - by user68759
    I have a subscription based website that interacts with a 3rd party system to handle the payments. The steps to process a new subscriber registration are as follow: The subscriber enters his/her details in the subscription form and click on the submit button. Assuming the details specified are valid, a new record is created in the database to store these details. The subscriber is then redirected to the website of the 3rd party system (similar to paypal) to process the payment. Once the payment is succesful, the 3rd party website then redirect the subscriber back to our website. At this time, I know that the payment was succesful, so the record in the database is updated to indicate that payment has been made successfully. A problem that I have found occurring quite often is that if a subscriber pays but does not complete the process correctly (e.g. uses the back browser, closes the window), his/her record in the database doesn't get updated about this. Accordingly, I don't know if s/he has paid by just looking the record and need to wait for the report from the 3rd party system to find this out. How do you solve this problem? PS. One of the main reasons to store their details into the database before the payment process is done is so they can come back to complete the payment without re-entering their details again. For example, when their credit cards were rejected by the 3rd party system and they need to sort this out with their financial institution which may take a while.

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  • Should a new language compiler target the JVM?

    - by Pindatjuh
    I'm developing a new language. My initial target was to compile to native x86 for the Windows platform, but now I am in doubt. I've seen some new languages target the JVM (most notable Scala and Clojure). Ofcourse it's not possible to port every language easily to the JVM; to do so, it may lead to small changes to the language and it's design. So that's the reason behind this doubt, and thus this question: Is targetting the JVM a good idea, when creating a compiler for a new language? Or should I stick with x86? I have experience in generating JVM bytecode. Are there any workarounds to JVM's GC? The language has deterministic implicit memory management. How to produce JIT-compatible bytecode, such that it will get the highest speedup? Is it similar to compiling for IA-32, such as the 4-1-1 muops pattern on Pentium? I can imagine some advantages (please correct me if I'm wrong): JVM bytecode is easier than x86. Like x86 communicates with Windows, JVM communicates with the Java Foundation Classes. To provide I/O, Threading, GUI, etc. Implementing "lightweight"-threads.I've seen a very clever implementation of this at http://www.malhar.net/sriram/kilim/. Most advantages of the Java Runtime (portability, etc.) The disadvantages, as I imagined, are: Less freedom? On x86 it'll be more easy to create low-level constructs, while JVM has a higher level (more abstract) processor. Most disadvantages of the Java Runtime (no native dynamic typing, etc.)

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  • Generalizing Fibonacci sequence with SICStus Prolog

    - by Christophe Herreman
    I'm trying to find a solution for a query on a generalized Fibonacci sequence (GFS). The query is: are there any GFS that have 885 as their 12th number? The initial 2 numbers may be restricted between 1 and 10. I already found the solution to find the Nth number in a sequence that starts at (1, 1) in which I explicitly define the initial numbers. Here is what I have for this: fib(1, 1). fib(2, 1). fib(N, X) :- N #> 1, Nmin1 #= N - 1, Nmin2 #= N - 2, fib(Nmin1, Xmin1), fib(Nmin2, Xmin2), X #= Xmin1 + Xmin2. For the query mentioned I thought the following would do the trick, in which I reuse the fib method without defining the initial numbers explicitly since this now needs to be done dynamically: fib2 :- X1 in 1..10, X2 in 1..10, fib(1, X1), fib(2, X2), fib(12, 885). ... but this does not seem to work. Is it not possible this way to define the initial numbers, or am I doing something terribly wrong? I'm not asking for the solution, but any advice that could help me solve this would be greatly appreciated.

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  • Displaying emails in a JTable (Java Swing)

    - by Paul
    Hi I'm new to all this. I have been trying to display fetched emails in a JTable using the JavaMail add-on. However when I ask the program to set the value it never does. I have been working in NetBeans if that is any help? the fetchMail class finds all may on a server. The gui class is used to display all emails in a table as well as creating mail. You will probably think that I have tried it like a bull in a china shop, I am new to Java and trying to give myself a challenge. Any help/advice would be greatly appreciated fetchMail: package mail; import java.util.; import java.io.; import java.text.DateFormat; import java.text.SimpleDateFormat; import javax.mail.; import javax.mail.internet.; import javax.mail.search.; import javax.activation.; public class fetchMail { public void fetch(String username, String pass, String search){ MessagesTableModel tableModel = new MessagesTableModel(); String complete; DateFormat df = new SimpleDateFormat("dd/MM/yyyy"); gui gui = new gui(); // SUBSTITUTE YOUR ISP's POP3 SERVER HERE!!! String host = "imap.gmail.com"; // SUBSTITUTE YOUR USERNAME AND PASSWORD TO ACCESS E-MAIL HERE!!! String user = username; String password = pass; // SUBSTITUTE YOUR SUBJECT SUBSTRING TO SEARCH HERE!!! String subjectSubstringToSearch = search; // Get a session. Use a blank Properties object. Session session = Session.getInstance(new Properties()); Properties props = System.getProperties(); props.setProperty("mail.store.protocol", "imaps"); props.setProperty("mail.imap.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); props.setProperty("mail.imap.socketFactory.fallback", "false"); try { // Get a Store object Store store = session.getStore("imaps"); store.connect(host, user, password); // Get "INBOX" Folder fldr = store.getFolder("INBOX"); fldr.open(Folder.READ_WRITE); int count = fldr.getMessageCount(); System.out.println(count + " total messages"); // Message numebers start at 1 for(int i = 1; i <= count; i++) { // Get a message by its sequence number Message m = fldr.getMessage(i); // Get some headers Date date = m.getSentDate(); int pos = i - 1; String d = df.format(date); Address [] from = m.getFrom(); String subj = m.getSubject(); String mimeType = m.getContentType(); complete = date + "\t" + from[0] + "\t" + subj + "\t" + mimeType; //tableModel.setMessages(m); gui.setDate(d, pos); // System.out.println(d + " " + i); } // Search for e-mails by some subject substring String pattern = subjectSubstringToSearch; SubjectTerm st = new SubjectTerm(pattern); // Get some message references Message [] found = fldr.search(st); System.out.println(found.length + " messages matched Subject pattern \"" + pattern + "\""); for (int i = 0; i < found.length; i++) { Message m = found[i]; // Get some headers Date date = m.getSentDate(); Address [] from = m.getFrom(); String subj = m.getSubject(); String mimeType = m.getContentType(); //System.out.println(date + "\t" + from[0] + "\t" + // subj + "\t" + mimeType); Object o = m.getContent(); if (o instanceof String) { // System.out.println("**This is a String Message**"); // System.out.println((String)o); } else if (o instanceof Multipart) { // System.out.print("**This is a Multipart Message. "); Multipart mp = (Multipart)o; int count3 = mp.getCount(); // System.out.println("It has " + count3 + // " BodyParts in it**"); for (int j = 0; j < count3; j++) { // Part are numbered starting at 0 BodyPart b = mp.getBodyPart(j); String mimeType2 = b.getContentType(); // System.out.println( "BodyPart " + (j + 1) + // " is of MimeType " + mimeType); Object o2 = b.getContent(); if (o2 instanceof String) { // System.out.println("**This is a String BodyPart**"); // System.out.println((String)o2); } else if (o2 instanceof Multipart) { // System.out.print( // "**This BodyPart is a nested Multipart. "); Multipart mp2 = (Multipart)o2; int count2 = mp2.getCount(); // System.out.println("It has " + count2 + // "further BodyParts in it**"); } else if (o2 instanceof InputStream) { // System.out.println( // "**This is an InputStream BodyPart**"); } } //End of for } else if (o instanceof InputStream) { // System.out.println("**This is an InputStream message**"); InputStream is = (InputStream)o; // Assumes character content (not binary images) int c; while ((c = is.read()) != -1) { // System.out.write(c); } } // Uncomment to set "delete" flag on the message //m.setFlag(Flags.Flag.DELETED,true); } //End of for // "true" actually deletes flagged messages from folder fldr.close(true); store.close(); } catch (MessagingException mex) { // Prints all nested (chained) exceptions as well mex.printStackTrace(); } catch (IOException ioex) { ioex.printStackTrace(); } } } gui: /* * gui.java * * Created on 13-May-2010, 18:29:30 */ package mail; import java.text.DateFormat; import java.text.FieldPosition; import java.text.ParsePosition; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Vector; import javax.mail.Address; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.ListSelectionModel; import javax.swing.event.ListSelectionEvent; import javax.swing.event.ListSelectionListener; import javax.swing.event.TableModelListener; import javax.swing.table.DefaultTableModel; import javax.swing.table.TableModel; public class gui extends javax.swing.JFrame { private MessagesTableModel tableModel; // Table listing messages. private JTable table; String date; /** Creates new form gui */ public gui() { initComponents(); } @SuppressWarnings("unchecked") private void initComponents() { recieve = new javax.swing.JButton(); jButton1 = new javax.swing.JButton(); jScrollPane1 = new javax.swing.JScrollPane(); inboxTable = new javax.swing.JTable(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); recieve.setText("Receve"); recieve.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { recieveActionPerformed(evt); } }); jButton1.setText("new"); jButton1.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { jButton1ActionPerformed(evt); } }); inboxTable.setModel(new javax.swing.table.DefaultTableModel( new Object [][] { {null, null, null}, {null, null, null}, {null, null, null}, {null, null, null} }, new String [] { "Date", "subject", "sender" } ) { Class[] types = new Class [] { java.lang.String.class, java.lang.String.class, java.lang.String.class }; public Class getColumnClass(int columnIndex) { return types [columnIndex]; } }); jScrollPane1.setViewportView(inboxTable); inboxTable.getColumnModel().getColumn(0).setResizable(false); inboxTable.getColumnModel().getColumn(1).setResizable(false); inboxTable.getColumnModel().getColumn(2).setResizable(false); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(39, 39, 39) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 558, javax.swing.GroupLayout.PREFERRED_SIZE) .addGroup(layout.createSequentialGroup() .addComponent(recieve) .addGap(18, 18, 18) .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE))) .addGap(73, 73, 73)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(31, 31, 31) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(recieve) .addComponent(jButton1)) .addGap(18, 18, 18) .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 258, javax.swing.GroupLayout.PREFERRED_SIZE) .addContainerGap(179, Short.MAX_VALUE)) ); pack(); }// </editor-fold> private void recieveActionPerformed(java.awt.event.ActionEvent evt) { fetchMail fetch = new fetchMail(); fetch.fetch(email goes here, password goes here, search goes here); } private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) { createMail create = new createMail(); centerW center = new centerW(); //create.attVis(); center.center(create); create.setVisible(true); } public void setDate(String Date, int pos){ //pos = pos + 1; String [] s = new String [5]; s[pos] = Date; inboxTable.setValueAt(Date, pos, 0); } public String getDate(){ return date; } /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new gui().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JTable inboxTable; private javax.swing.JButton jButton1; private javax.swing.JScrollPane jScrollPane1; private javax.swing.JButton recieve; // End of variables declaration }

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  • Which CMS do I need? Needs to be easy to post a certain kind of post

    - by Vian Esterhuizen
    Hi, I'm creating a site for a video store and it needs to be CMS. I'm doing this for free so I need to use a free CMS like Wordpress, Drupal or Joomla. Do I need a new CMS, a plugin or some PHP of my own? What I need: User accounts Categories Custom post Here's the site as it stands with WP: http://sundancevideo.ca. Right now an experimental site to try to work this out. What I've done now, is created a "Draft" that includes a template table with images and text and so on. The user would then have to copy everything, past into a new post and replace necessary. This really isn't working well. As you may notice by the condition of the posts. What I would prefer is if it was integrated into the WP UI. Like a field for "Description" and field for "Image" where they can upload the images as necessary. This would then generate post, with a table including all the information and images, for as many movies that were added in the UI. Please ask if I'm not being clear. Please help, any suggestions are welcome. Thank you, Vian

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  • compiling and running java on windows

    - by artur grzesiak
    I thought the task should be fairly easy, but my understanding of javac and java in general is rather poor. I am using Windows8 and would like to compile a single file.java that makes use of other classes. I successfully (at least without any warnings) compiled my file by calling: javac -cp relative_path_to_needed_classes relative_path_to_file_java\file.java Now if I want to run the result of compilation (file.class) by calling: java -cp relative_path_to_needed_classes relative_path_to_file_java\file I get: Error: Could not find or load main class relative_path_to_file_java\file I was trying a lot of combination to modify the -cp (eg. by adding .\;relative_path_to_file;) but still the closest where I get is: Exception in thread "main" java.lang.NoClassDefFoundError : relative_path_to_file\file (wrong name: file) The file from (wrong name: file) is the name of the file and the name of the public class within the file. I was reading a lot on SO and other sources but could not figure out what is wrong. Btw. as a result of compilation some other classes were created: file$1.class file$name1.class file$name2.class (where name1 and name2 are names of private classes within file.java) My questions are: What is (the most) probably source of my error / what am I doing wrong? What is the purpose of file$1.class? What is the minimum I should specify in -cp? May encoding play any role? Do every java class have to reside in a package? (rather not directly related to my issue) Do order of paths specified in -cp play any role in runtime?

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  • Need guidelines for optimizing WebGL performance by minimizing shader changes

    - by brainjam
    I'm trying to get an idea of the practicality of WebGL for rendering large architectural interior scenes, consisting of 100K's of triangles. These triangles are distributed over many objects, and there are many materials in the scene. On the other hand, there are no moving parts. And the materials tend to be fairly simple, mostly based on texture maps. There is a lot of texture map sharing .. for example all the chairs in scene will share a common map. There is also some multitexturing - up to three textures overlaid in a material. I've been doing a little experimentation and reading, and gather that frequently switching materials during a rendering pass will slow things down. For example, a scene with 200K triangles will have significant performance differences, depending on whether there are 10 or 1000 objects, assuming that each time an object is displayed a new material is set up. So it seems that if performance is important the scene should be sorted by materials so as to minimize material switching. What I'm looking for is guidelines on how to think of the overhead of various state changes, and where do I get the biggest bang for the buck. For example, what are the relative performance costs of, say, gl.useProgram(), gl.uniformMatrix4fv(), gl.drawElements() should I try to write ubershaders to minimize shader switching? should I try to aggregate geometry to minimize the number of gl.drawElements() calls I realize that mileage may vary depending on browser, OS, and graphics hardware. And I'm also not looking for heroic measures. Just some guidelines from people who have already had some experience in making scenes fast. I'll add that while I've had some experience with fixed-pipeline OpenGL programming in the past, I'm rather new to the WebGL/OpenGL ES 2.0 way of doing things.

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  • Protecting an Application's Memory From Tampering

    - by Changeling
    We are adding AES 256 bit encryption to our server and client applications for encrypting the TCP/IP traffic containing sensitive information. We will be rotating the keys daily. Because of that, the keys will be stored in memory with the applications. Key distribution process: Each server and client will have a list of initial Key Encryption Key's (KEK) by day If the client has just started up or the server has just started up, the client will request the daily key from the server using the initial key. The server will respond with the daily key, encrypted with the initial key. The daily key is a randomly generated set of alphanumeric characters. We are using AES 256 bit encryption. All subsequent communications will be encrypted using that daily key. Nightly, the client will request the new daily key from the server using the current daily key as the current KEK. After the client gets the new key, the new daily key will replace the old daily key. Is it possible for another bad application to gain access to this memory illegally or is this protected in Windows? The key will not be written to a file, only stored in a variable in memory. If an application can access the memory illegally, how can you protect the memory from tampering? We are using C++ and XP (Vista/7 may be an option in the future so I don't know if that changes the answer).

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  • How to handle update events on a ASP.NET GridView?

    - by Bogdan M
    Hello, This may sound silly, but I need to find out how to handle an Update event from a GridView. First of all, I have a DataSet, where there is a typed DataTable with a typed TableAdapter, based on a "select all query", with auto-generated Insert, Update, and Delete methods. Then, in my aspx page, I have an ObjectDataSource related to my typed TableAdapter on Select, Insert, Update and Delete methods. Finnally, I have a GridView bound to this ObjectDataSource, with default Edit, Update and Cancel links. How should I implement the edit functionality? Should I have something like this? protected void GridView_RowEditing(object sender, GridViewEditEventArgs e) { using(MyTableAdapter ta = new MyTableAdapter()) { ta.Update(...); TypedDataTable dt = ta.GetRecords(); this.GridView.DataSource = dt; this.GridView.DataBind(); } } In this scenario, I have the feeling that I update some changes to the DB, then I retrive and bind all the data, and not only the modified parts. Is there any way to update only the DataSet, and this to update on his turn the DataBase and the GridView? I do not want to retrive all the data after a CRUD operations is performed, I just want to retrive the changes made. Thanks. PS: I'm using .NET 3.5 and VS 2008 with SP1.

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  • Getting Feedburner Subscriber With CURL

    - by Eray Alakese
    I'm using FeedBurner Awareness API. XML data like this : <rsp stat="ok"> - <!-- This information is part of the FeedBurner Awareness API. If you want to hide this information, you may do so via your FeedBurner Account. --> - <feed id="9n66llmt1frfir51p0oa367ru4" uri="teknoblogo"> <entry date="2011-01-15" circulation="11" hits="18" reach="0"/> </feed> </rsp> I want to get circulation data (11) . I'm using this code: $whaturl="https://feedburner.google.com/api/awareness/1.0/GetFeedData?uri=teknoblogo"; //Initialize the Curl session $ch = curl_init(); //Set curl to return the data instead of printing it to the browser. curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); //Set the URL curl_setopt($ch, CURLOPT_URL, $whaturl); //Execute the fetch $data = curl_exec($ch); //Close the connection curl_close($ch); $xml = new SimpleXMLElement($data); $fb = $xml->feed->entry['circulation']; echo $fb; echo "OK"; But, returned data is blank. There isn't any error. Only return OK . How can i solve this ? EDIT : echo $data; returning blank, too.

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  • 'NoneType' object has no attribute 'data'

    - by Bill Jordan
    Hello guys, I am sending a SOAP request to my server and getting the response back. sample of the response string is shown below: <?xml version = '1.0' ?> <env:Envelope xmlns:env=http:////www.w3.org/2003/05/soap-envelop . .. .. <env:Body> <epas:get-all-config-resp xmlns:epas="urn:organization:epas:soap"> ^M ... ... <epas:property name="Tom">12</epas:property> > > <epas:property name="Alice">34</epas:property> > > <epas:property name="John">56</epas:property> > > <epas:property name="Danial">78</epas:property> > > <epas:property name="George">90</epas:property> > > <epas:property name="Luise">11</epas:property> ... ^M </env:Body? </env:Envelop> What I noticed in the response is that there is an extra character shown in the body which is "^M". Not sure if this could be the issue. Note the ^M shown! when I tried parsing the string returned from the server to get the names and values using the code sample: elements = minidom.parseString(xmldoc).getElementsByTagName("property") myDict = {} for element in elements: myDict[element.getAttribute('name')] = element.firstChild.data But, I am getting this error: 'NoneType' object has no attribute 'data'. May be its something to do with the "^M" shown on the xml response back! Any ideas/comments would be appreciated, Cheers

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  • ASP.NET application - Error when trying to connect to a SQL Server 2008 instance

    - by Pablo Dami
    Hi everyone! Despite that I’m a regular reader of this great forum, this is my first post on it. I believe that this community can help me with the following problem that I have. I’m trying to publish an ASP.NET website over an IIS 6.0 (Windows 2003 Server), and I have some troubles trying to connect to the database. Curiously, I have installed another ASP.NET website into the same IIS 6.0 with the same properties and security parameters and can connect without problems with the same database. The application that works fine is almost the same that the one that can’t connect with SQL Server (actually is the same but with several modifications). I’ll enumarate some information related to the problem: S.O: Windows 2003 Server SQL Server Engine: SQL Server 2008 SQL Server accept remote connections? Yes. ASP.NET version: 2.0.50727 The connections via TCP/IP are enabled to the SQL Server instance? Yes. The corresponding user that I have in the connection string, actually exists into the database with the “owner” role? Yes. ORM Tool used: nHibernate I get the following error when I try to run the aplication into the browser: Error while establishing a connection to the server. When connecting to SQL Server 2005, this failure may occur because the default settings SQL Server does not allow remote connections. (provider: Shared Memory Provider, error: 40 - Could not open a connection to SQL Server) In order to isolate the problem, I made some test. For example, using the web app that works fine I can connect without any problema with the database that uses the web app that can’t. With this evidence I concluded that the problem is within the web app and not into the SQL Server instance. I also google it my problem but sadly I can't find nothing usefull to solve it. If someone can help me I’ll appreciate that. Thank you so much for your time!

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  • Show progress during a long Ajax call

    - by kousen
    I have a simple web site (http://www.kousenit.com/twitterfollowervalue) that computes a quantity based on a person's Twitter followers. Since the Twitter API only returns followers 100 at a time, a complete process may involve lots of calls. At the moment, I have an Ajax call to a method that runs the Twitter loop. The method looks like (Groovy): def updateFollowers() { def slurper = new XmlSlurper() followers = [] def next = -1 while (next) { def url = "http://api.twitter.com/1/statuses/followers.xml?id=$id&cursor=$next" def response = slurper.parse(url) response.users.user.each { u -> followers << new TwitterUser(... process data ...) } next = response.next_cursor.toBigInteger() } return followers } This is invoked from a controller called renderTTFV.groovy. I call the controller via an Ajax call using the prototype library: On my web page, in the header section (JavaScript): function displayTTFV() { new Ajax.Updater('ttfv','renderTTFV.groovy', {}); } and there's a div in the body of the page that updates when the call is complete. Everything is working, but the updateFollowers method can take a fair amount of time. Is there some way I could return a progress value? For example, I'd like to update the web page on every iteration. I know ahead of time how many iterations there will be. I just can't figure out a way to update the page in the middle of that loop. Any suggestions would be appreciated.

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  • postgres - ERROR: operator does not exist

    - by cino21122
    Again, I have a function that works fine locally, but moving it online yields a big fat error... Taking a cue from a response in which someone had pointed out the number of arguments I was passing wasn't accurate, I double-checked in this situation to be certain that I am passing 5 arguments to the function itself... Query failed: ERROR: operator does not exist: point <@> point HINT: No operator matches the given name and argument type(s). You may need to add explicit type casts. The query is this: BEGIN; SELECT zip_proximity_sum('zc', (SELECT g.lat FROM geocoded g LEFT JOIN masterfile m ON g.recordid = m.id WHERE m.zip = '10050' ORDER BY m.id LIMIT 1), (SELECT g.lon FROM geocoded g LEFT JOIN masterfile m ON g.recordid = m.id WHERE m.zip = '10050' ORDER BY m.id LIMIT 1), (SELECT m.zip FROM geocoded g LEFT JOIN masterfile m ON g.recordid = m.id WHERE m.zip = '10050' ORDER BY m.id LIMIT 1) ,10); The PG function is this: CREATE OR REPLACE FUNCTION zip_proximity_sum(refcursor, numeric, numeric, character, numeric) RETURNS refcursor AS $BODY$ BEGIN OPEN $1 FOR SELECT r.zip, point($2,$3) <@> point(g.lat, g.lon) AS distance FROM geocoded g LEFT JOIN masterfile r ON g.recordid = r.id WHERE (geo_distance( point($2,$3),point(g.lat,g.lon)) < $5) ORDER BY r.zip, distance; RETURN $1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 100;

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  • How do I dismiss an NSPanel when creating or opening a new document?

    - by mipadi
    I am working on a document-based Cocoa application. At startup, the user is presented with a "welcome panel" (of type NSPanel) with buttons for common actions like "Create New Document" and "Open Existing Document". These actions are linked to the first responder's newDocument: and openDocument: actions, respectively, just like the matching items in the File menu. Everything works as expected...with two caveats: The welcome panel is not dismissed when creating or opening a new document. Document windows do not have focus when they are created. I have partially solved #1 by making my application controller a delegate of the welcome panel. When clicking the "Open Existing Document" button, the panel resigns its key status (since a file browser dialog is being opened), so I can close the panel in the delegate's windowDidResignKey: method. However, I can't figure out how to close the panel when creating a new document, since I can't find a notification that is posted, or a delegate method that is called, when creating a new document. And ultimately, #2 is still a problem, since the document windows don't gain focus when they're created. I have only subclassed NSDocument -- I'm not using a custom document or window controller at all. I've also tried changing the panel to an NSWindow, thinking that an NSWindow may behave differently, but the same problems are occurring.

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  • Combining cache methods - memcache/disk based

    - by Industrial
    Hi! Here's the deal. We would have taken the complete static html road to solve performance issues, but since the site will be partially dynamic, this won't work out for us. What we have thought of instead is using memcache + eAccelerator to speed up PHP and take care of caching for the most used data. Here's our two approaches that we have thought of right now: Using memcache on all<< major queries and leaving it alone to do what it does best. Usinc memcache for most commonly retrieved data, and combining with a standard harddrive-stored cache for further usage. The major advantage of only using memcache is of course the performance, but as users increases, the memory usage gets heavy. Combining the two sounds like a more natural approach to us, even though the theoretical compromize in performance. Memcached appears to have some replication features available as well, which may come handy when it's time to increase the nodes. What approach should we use? - Is it stupid to compromize and combine the two methods? Should we insted be focusing on utilizing memcache and instead focusing on upgrading the memory as the load increases with the number of users? Thanks a lot!

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  • Trying to insert a row using stored procedured with a parameter binded to an expression.

    - by Arvind Singh
    Environment: asp.net 3.5 (C# and VB) , Ms-sql server 2005 express Tables Table:tableUser ID (primary key) username Table:userSchedule ID (primary key) thecreator (foreign key = tableUser.ID) other fields I have created a procedure that accepts a parameter username and gets the userid and inserts a row in Table:userSchedule Problem: Using stored procedure with datalist control to only fetch data from the database by passing the current username using statement below works fine protected void SqlDataSourceGetUserID_Selecting(object sender, SqlDataSourceSelectingEventArgs e) { e.Command.Parameters["@CurrentUserName"].Value = Context.User.Identity.Name; } But while inserting using DetailsView it shows error Procedure or function OASNewSchedule has too many arguments specified. I did use protected void SqlDataSourceCreateNewSchedule_Selecting(object sender, SqlDataSourceSelectingEventArgs e) { e.Command.Parameters["@CreatedBy"].Value = Context.User.Identity.Name; } DetailsView properties: autogen fields: off, default mode: insert, it shows all the fields that may not be expected by the procedure like ID (primary key) not required in procedure and CreatedBy (user id ) field . So I tried removing the 2 fields from detailsview and shows error Cannot insert the value NULL into column 'CreatedBy', table 'D:\OAS\OAS\APP_DATA\ASPNETDB.MDF.dbo.OASTest'; column does not allow nulls. INSERT fails. The statement has been terminated. For some reason parameters value is not being set. Can anybody bother to understand this and help?

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  • wcf trying to set up tracing to debug, not writing to log file

    - by joey j
    here's my web.config, running a WCF service in an application on IIS7, but nothing is being written to the specified file. permission on the file has been granted for everyone. </listeners> I can add a service reference just fine. I then try to call the service from a windows app and, after a few minutes, get an error on the machine running the windows app "Client is unable to finish the security negotiation within the configured timeout (00:00:00). The current negotiation leg is 1 (00:00:00)." but absolutely nothing is written to the trace log file specified in config. Is there something else I need to do to enable tracing? thanks for your help EDIT: "sources" section now matches the section recommended here: http://msdn.microsoft.com/en-us/library/aa702726.aspx I've added the "diagnostics and the event viewer shows: "Message Logging has been turned on. Sensitive information may be logged in the clear, even if it was encrypted on the wire: for example, message bodies. Process Name: w3wp Process ID: 1784 " but the log file is still empty

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