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  • Threading Overview

    - by ACShorten
    One of the major features of the batch framework is the ability to support multi-threading. The multi-threading support allows a site to increase throughput on an individual batch job by splitting the total workload across multiple individual threads. This means each thread has fine level control over a segment of the total data volume at any time. The idea behind the threading is based upon the notion that "many hands make light work". Each thread takes a segment of data in parallel and operates on that smaller set. The object identifier allocation algorithm built into the product randomly assigns keys to help ensure an even distribution of the numbers of records across the threads and to minimize resource and lock contention. The best way to visualize the concept of threading is to use a "pie" analogy. Imagine the total workset for a batch job is a "pie". If you split that pie into equal sized segments, each segment would represent an individual thread. The concept of threading has advantages and disadvantages: Smaller elapsed runtimes - Jobs that are multi-threaded finish earlier than jobs that are single threaded. With smaller amounts of work to do, jobs with threading will finish earlier. Note: The elapsed runtime of the threads is rarely proportional to the number of threads executed. Even though contention is minimized, some contention does exist for resources which can adversely affect runtime. Threads can be managed individually – Each thread can be started individually and can also be restarted individually in case of failure. If you need to rerun thread X then that is the only thread that needs to be resubmitted. Threading can be somewhat dynamic – The number of threads that are run on any instance can be varied as the thread number and thread limit are parameters passed to the job at runtime. They can also be configured using the configuration files outlined in this document and the relevant manuals.Note: Threading is not dynamic after the job has been submitted Failure risk due to data issues with threading is reduced – As mentioned earlier individual threads can be restarted in case of failure. This limits the risk to the total job if there is a data issue with a particular thread or a group of threads. Number of threads is not infinite – As with any resource there is a theoretical limit. While the thread limit can be up to 1000 threads, the number of threads you can physically execute will be limited by the CPU and IO resources available to the job at execution time. Theoretically with the objects identifiers evenly spread across the threads the elapsed runtime for the threads should all be the same. In other words, when executing in multiple threads theoretically all the threads should finish at the same time. Whilst this is possible, it is also possible that individual threads may take longer than other threads for the following reasons: Workloads within the threads are not always the same - Whilst each thread is operating on the roughly the same amounts of objects, the amount of processing for each object is not always the same. For example, an account may have a more complex rate which requires more processing or a meter has a complex amount of configuration to process. If a thread has a higher proportion of objects with complex processing it will take longer than a thread with simple processing. The amount of processing is dependent on the configuration of the individual data for the job. Data may be skewed – Even though the object identifier generation algorithm attempts to spread the object identifiers across threads there are some jobs that use additional factors to select records for processing. If any of those factors exhibit any data skew then certain threads may finish later. For example, if more accounts are allocated to a particular part of a schedule then threads in that schedule may finish later than other threads executed. Threading is important to the success of individual jobs. For more guidelines and techniques for optimizing threading refer to Multi-Threading Guidelines in the Batch Best Practices for Oracle Utilities Application Framework based products (Doc Id: 836362.1) whitepaper available from My Oracle Support

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  • Concurrent Affairs

    - by Tony Davis
    I once wrote an editorial, multi-core mania, on the conundrum of ever-increasing numbers of processor cores, but without the concurrent programming techniques to get anywhere near exploiting their performance potential. I came to the.controversial.conclusion that, while the problem loomed for all procedural languages, it was not a big issue for the vast majority of programmers. Two years later, I still think most programmers don't concern themselves overly with this issue, but I do think that's a bigger problem than I originally implied. Firstly, is the performance boost from writing code that can fully exploit all available cores worth the cost of the additional programming complexity? Right now, with quad-core processors that, at best, can make our programs four times faster, the answer is still no for many applications. But what happens in a few years, as the number of cores grows to 100 or even 1000? At this point, it becomes very hard to ignore the potential gains from exploiting concurrency. Possibly, I was optimistic to assume that, by the time we have 100-core processors, and most applications really needed to exploit them, some technology would be around to allow us to do so with relative ease. The ideal solution would be one that allows programmers to forget about the problem, in much the same way that garbage collection removed the need to worry too much about memory allocation. From all I can find on the topic, though, there is only a remote likelihood that we'll ever have a compiler that takes a program written in a single-threaded style and "auto-magically" converts it into an efficient, correct, multi-threaded program. At the same time, it seems clear that what is currently the most common solution, multi-threaded programming with shared memory, is unsustainable. As soon as a piece of state can be changed by a different thread of execution, the potential number of execution paths through your program grows exponentially with the number of threads. If you have two threads, each executing n instructions, then there are 2^n possible "interleavings" of those instructions. Of course, many of those interleavings will have identical behavior, but several won't. Not only does this make understanding how a program works an order of magnitude harder, but it will also result in irreproducible, non-deterministic, bugs. And of course, the problem will be many times worse when you have a hundred or a thousand threads. So what is the answer? All of the possible alternatives require a change in the way we write programs and, currently, seem to be plagued by performance issues. Software transactional memory (STM) applies the ideas of database transactions, and optimistic concurrency control, to memory. However, working out how to break down your program into sufficiently small transactions, so as to avoid contention issues, isn't easy. Another approach is concurrency with actors, where instead of having threads share memory, each thread runs in complete isolation, and communicates with others by passing messages. It simplifies concurrent programs but still has performance issues, if the threads need to operate on the same large piece of data. There are doubtless other possible solutions that I haven't mentioned, and I would love to know to what extent you, as a developer, are considering the problem of multi-core concurrency, what solution you currently favor, and why. Cheers, Tony.

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  • Canonical configuration for multiple-instance Postfix?

    - by threecheeseopera
    I recently attempted to reconfigure an existing single-instance Postfix server (multi-homed) to support multiple MTA instances, but failed miserably (read: open relay, nastygram from ISP). It appears that there are several methods that can be used to accomplish this, and the various (and numerous) secondary sources that I found online were 'all over the map' with respect to which they used/glued together. Can anyone provide a working configuration (or tips) that use postmulti to manage a multi-instance Postfix setup?

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  • update jframe in java or revalidate/repaint/ panel

    - by user1516251
    How to update a java frame with changed content I want to update a frame or just the panel with updated content. What do I use for this Here is where i want to revalidate the frame or repaint mainpanel or whatever will work I have tried a number of things, but none of them have worked. public void actionPerformed(ActionEvent e) { //System.out.println(e.getActionCommand()); if (e.getActionCommand().equals("advance")) { multi--; // Revalidate update repaint here <<<<<<<<<<<<<<<<<<< } else if (e.getActionCommand().equals("reverse")) { multi++; // Revalidate update repaint here <<<<<<<<<<<<<<<<<<< } else { openURL(e.getActionCommand()); } } Here is the whole java file /* * * */ package build; import java.lang.reflect.Method; import javax.swing.JOptionPane; import java.util.Arrays; import java.util.*; import java.util.ArrayList; import javax.swing.*; import javax.swing.AbstractButton; import javax.swing.JScrollPane; import javax.swing.JButton; import javax.swing.JPanel; import javax.swing.JFrame; import javax.swing.ImageIcon; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; /* * ButtonDemo.java requires the following files: * images/right.gif * images/middle.gif * images/left.gif */ public class StockTable extends JPanel implements ActionListener { static int multi = 1; int roll = 0; static TextVars textvars = new TextVars(); static final String[] browsers = { "firefox", "opera", "konqueror", "epiphany", "seamonkey", "galeon", "kazehakase", "mozilla", "netscape" }; JFrame frame; JPanel mainpanel, panel1, panel2, panel3, panel4, panel2left, panel2center, panel2right; JButton stknames_btn[] = new JButton[textvars.getNumberOfStocks()]; JLabel label[] = new JLabel[textvars.getNumberOfStocks()]; JLabel headlabel, dayspan, namelabel; JRadioButton radioButton; JButton button; JScrollPane scrollpane; int wid = 825; public JPanel createContentPane() { mainpanel = new JPanel(); mainpanel.setPreferredSize(new Dimension(wid, 800)); mainpanel.setLayout(new GridBagLayout()); GridBagConstraints c = new GridBagConstraints(); panel1 = new JPanel(); panel1.setPreferredSize(new Dimension(wid, 25)); c.gridx = 0; c.gridy = 0; c.insets = new Insets(0,0,0,0); mainpanel.add(panel1, c); // Panel 2------------ panel2 = new JPanel(); panel2.setPreferredSize(new Dimension(wid, 51)); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0,0,0,0); mainpanel.add(panel2, c); panel2left = new JPanel(); panel2left.setPreferredSize(new Dimension(270, 51)); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2left, c); panel2center = new JPanel(); panel2center.setPreferredSize(new Dimension(258, 51)); c.gridx = 1; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2center, c); panel2right = new JPanel(); panel2right.setPreferredSize(new Dimension(270, 51)); c.gridx = 2; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2right, c); // ------------------ panel3 = new JPanel(); panel3.setLayout(new GridBagLayout()); scrollpane = new JScrollPane(panel3); scrollpane.setPreferredSize(new Dimension(wid, 675)); c.gridx = 0; c.gridy = 2; c.insets = new Insets(0,0,0,0); mainpanel.add(scrollpane, c); ImageIcon leftButtonIcon = createImageIcon("images/right.gif"); //b1 = new JButton("Disable middle button", leftButtonIcon); //b1.setVerticalTextPosition(AbstractButton.CENTER); //b1.setHorizontalTextPosition(AbstractButton.LEADING); //aka LEFT, for left-to-right locales //b1.setMnemonic(KeyEvent.VK_D); //b1.setActionCommand("disable"); //Listen for actions on buttons 1 //b1.addActionListener(this); //b1.setToolTipText("Click this button to disable the middle button."); //Add Components to this container, using the default FlowLayout. //add(b1); headlabel = new JLabel("hellorow1"); c.gridx = 0; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(headlabel, c); radioButton = new JRadioButton("Percentage"); c.gridx = 2; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(radioButton, c); radioButton = new JRadioButton("Days Range"); c.gridx = 3; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(radioButton, c); radioButton = new JRadioButton("Open / Close"); c.gridx = 4; c.gridy = 0; c.insets = new Insets(0, 0, 0,0 ); panel1.add(radioButton, c); button = new JButton("<<"); button.setPreferredSize(new Dimension(50, 50)); button.setActionCommand("reverse"); button.addActionListener(this); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2left.add(button, c); dayspan = new JLabel("hellorow2"); dayspan.setHorizontalAlignment(JLabel.CENTER); dayspan.setVerticalAlignment(JLabel.CENTER); dayspan.setPreferredSize(new Dimension(270, 50)); c.gridx = 1; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2center.add(dayspan, c); button = new JButton(">>"); button.setPreferredSize(new Dimension(50, 50)); button.setActionCommand("advance"); button.addActionListener(this); if (multi == 0) { button.setEnabled(false); } else { button.setEnabled(true); } c.gridx = 2; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2right.add(button, c); int availSpace_int = textvars.getStocks().size()-textvars.getNumberOfStocks()*7; ArrayList<String[]> stocknames = textvars.getStockNames(); ArrayList<String[]> stocks = textvars.getStocks(); for (int column = 0; column < 8; column++) { for (int row = 0; row < textvars.getNumberOfStocks(); row++) { if (column==0) { if (row==0) { namelabel = new JLabel(stocknames.get(0)[0]); namelabel.setVerticalAlignment(JLabel.CENTER); namelabel.setHorizontalAlignment(JLabel.CENTER); namelabel.setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0, 0, 0, 0); panel3.add(namelabel, c); } else { stknames_btn[row] = new JButton(stocknames.get(row)[0], leftButtonIcon); stknames_btn[row].setVerticalTextPosition(AbstractButton.CENTER); stknames_btn[row].setActionCommand(stocknames.get(row)[1]); stknames_btn[row].addActionListener(this); stknames_btn[row].setToolTipText("go to Google Finance "+stocknames.get(row)[0]); stknames_btn[row].setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0, 0, 0, 0); //scrollpane.add(stknames[row], c); panel3.add(stknames_btn[row], c); } } else { label[row]= new JLabel(textvars.getStocks().get(columnMulti(multi))[1]); label[row].setBorder(BorderFactory.createLineBorder(Color.black)); label[row].setVerticalAlignment(JLabel.CENTER); label[row].setHorizontalAlignment(JLabel.CENTER); label[row].setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0,0,0,0); panel3.add(label[row], c); } } } return mainpanel; } public void actionPerformed(ActionEvent e) { //System.out.println(e.getActionCommand()); if (e.getActionCommand().equals("advance")) { multi--; } else if (e.getActionCommand().equals("reverse")) { multi++; } else { openURL(e.getActionCommand()); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = StockTable.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } public static void openURL(String url) { String osName = System.getProperty("os.name"); try { if (osName.startsWith("Mac OS")) { Class<?> fileMgr = Class.forName("com.apple.eio.FileManager"); Method openURL = fileMgr.getDeclaredMethod("openURL", new Class[] {String.class}); openURL.invoke(null, new Object[] {url}); } else if (osName.startsWith("Windows")) { Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + url); } else { //assume Unix or Linux boolean found = false; for (String browser : browsers) if (!found) { found = Runtime.getRuntime().exec( new String[] {"which", browser}).waitFor() == 0; if (found) Runtime.getRuntime().exec(new String[] {browser, url}); } if (!found) throw new Exception(Arrays.toString(browsers)); } } catch (Exception e) { JOptionPane.showMessageDialog(null, "Error attempting to launch web browser\n" + e.toString()); } } int reit = 0; int start = textvars.getStocks().size()-((textvars.getNumberOfStocks()*5)*7)-1; public int columnMulti(int multi) { reit++; start++; if (reit == textvars.getNumberOfStocks()) { reit = 0; start=start+64; } //start = start - (multi*(textvars.getNumberOfStocks())); return start; } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. JFrame frame = new JFrame("Stock Table"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. StockTable newContentPane = new StockTable(); //newContentPane.setOpaque(true); //content panes must be opaque //frame.setContentPane(newContentPane); frame.setContentPane(newContentPane.createContentPane()); frame.setSize(800, 800); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } }

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  • ob_start() is partially capturing data

    - by AAA
    I am using the following code: PHP: // Generate Guid function NewGuid() { $s = strtoupper(uniqid(rand(),true)); $guidText = substr($s,0,8) . '-' . substr($s,8,4) . '-' . substr($s,12,4). '-' . substr($s,16,4). '-' . substr($s,20); return $guidText; } // End Generate Guid $Guid = NewGuid(); $alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ'; function base_encode($num, $alphabet) { $base_count = strlen($alphabet); $encoded = ''; while ($num >= $base_count) { $div = $num/$base_count; $mod = ($num-($base_count*intval($div))); $encoded = $alphabet[$mod] . $encoded; $num = intval($div); } if ($num) $encoded = $alphabet[$num] . $encoded; return $encoded; } function base_decode($num, $alphabet) { $decoded = 0; $multi = 1; while (strlen($num) > 0) { $digit = $num[strlen($num)-1]; $decoded += $multi * strpos($alphabet, $digit); $multi = $multi * strlen($alphabet); $num = substr($num, 0, -1); } return $decoded; } ob_start(); echo base_encode($Guid, $alphabet); //should output: bUKpk $theid = ob_get_contents(); ob_get_clean(); The problem: When i echo $theid, it shows the complete entry, but as it is being inserted into the database, only the first entry in the sequence gets inserted, for example for the entry buKPK, only 'b' is being inserted not the rest.

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  • Windows Build System: How to build a project (from its source code) which doesn't have *.sln or Visu

    - by claws
    I'm facing this problem. So, I need to build the support libraries (zlib, libtiff, libpng, libxml2, libiconv) with "Multithreaded DLL" (/MD) & "Multithreaded DLL Debug" (/MDd) run-time options. But the problem is there is no direct way . I mean there is no *.sln / *.vcproj file which I can open in Visual C++ and build it. I'm aware with the GNU build system: $./configure --with-all-sorts-of-required-switches $./make $./make install During my search I've encountered with something called CMake which generates *.vcproj & *.sln file but for that CMakeLists.txt is required. Not all projects provide CMakeLists.txt. I've never compiled anything from Visual C++ Command Line. Generally most projects provide makefile. Now how do I generate *.vcproj / *.sln from this? Can I compile with mingw-make of MinGW? If I can, how do I set different options ("Multi-Threaded"(/MT), "Multi-Threaded Debug"(/MTd), "Multi-Threaded DLL"(/MD), "Multi-Threaded DLL Debug"(/MDd)) for run-time libraries? I don't know what other ways are available. Please throw some light on this.

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  • Parsing a JSON feed from YQL using jQuery

    - by Keith
    I am using YQL's query.multi to grab multiple feeds so I can parse a single JSON feed with jQuery and reduce the number of connections I'm making. In order to parse a single feed, I need to be able to check the type of result (photo, item, entry, etc) so I can pull out items in specific ways. Because of the way the items are nested within the JSON feed, I'm not sure the best way to loop through the results and check the type and then loop through the items to display them. Here is a YQL (http://developer.yahoo.com/yql/console/) query.multi example and you can see three different result types (entry, photo, and item) and then the items nested within them: select * from query.multi where queries= "select * from twitter.user.timeline where id='twitter'; select * from flickr.photos.search where has_geo='true' and text='san francisco'; select * from delicious.feeds.popular" or here is the JSON feed itself: http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20query.multi%20where%20queries%3D%22select%20*%20from%20flickr.photos.search%20where%20user_id%3D'23433895%40N00'%3Bselect%20*%20from%20delicious.feeds%20where%20username%3D'keith.muth'%3Bselect%20*%20from%20twitter.user.timeline%20where%20id%3D'keithmuth'%22&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=

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  • txt file read/overwrite/append. Is this feasible? (Visual C#)

    - by Arcadian
    Hi, I'm writing a program for some data entry I have to periodically do. I have begun testing a few things that the program will have to do but i'm not sure about this part. What i need this part to do is: read a .txt file of data take the first 12 characters from each line take the first 12 characters from each line of the data that has been entered in a multi-line text box compare the two lists line by line if one of the 12 character blocks from the multi-line text box match one of the blocks in the .txt file then overwrite that entire line (only 17 characters in total) if one of the 12 character blocks from the multi-line text box DO NOT match any of the blocks in the.txt file then append that entire line to the file thats all it has to do. i'll do an example: TXT FILE: G01:78:08:32 JG05 G08:80:93:10 JG02 G28:58:29:28 JG04 MULTI-LINE TEXT BOX: G01:78:08:32 JG06 G28:58:29:28 JG03 G32:10:18:14 JG01 G32:18:50:78 JG07 RESULTING TXT FILE: G01:78:08:32 JG06 G08:80:93:10 JG02 G28:58:29:28 JG03 G32:10:18:14 JG01 G32:18:50:78 JG07 as you can see lines 1 and 3 were overwriten, line 2 was left alone as it did not match any blocks in the text box, lines 4 and 5 were appended to the file. thats all i want it to do. How do i go about this? Thanks in advance

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  • C# 4: The Curious ConcurrentDictionary

    - by James Michael Hare
    In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking.  The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations.  In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did?  Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests.  Obviously there's many things we can do with a dictionary.  One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache.  So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor.  This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit").  However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss").  So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10:  11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14:  15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19:  20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22:  23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward.  Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: };                    Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete.  Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances.  All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8:  9:  10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17:  18:  19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category.  The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend.  In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution.  But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds".  So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it).  And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here.  I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well.  This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us?  Well, as in all things, ConcurrentDictionary is not a panacea.  It won't solve all your woes and it shouldn't be the only Dictionary you ever use.  So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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  • How to safely reboot via First Boot script

    - by unixman
    With the cost and performance benefits of the SPARC T4 and SPARC T5 systems undeniably validated, the banking sector is actively moving to Solaris 11.  I was recently asked to help a banking customer of ours look at migrating some of their Solaris 10 logic over to Solaris 11.  While we've introduced a number of holistic improvements in Solaris 11, in terms of how we ease long-term software lifecycle management, it is important to appreciate that customers may not be able to move all of their Solaris 10 scripts and procedures at once; there are years of scripts that reflect fine-tuned requirements of proprietary banking software that gets layered on top of the operating system. One of these requirements is to go through a cycle of reboots, after the system is installed, in order to ensure appropriate software dependencies and various configuration files are in-place. While Solaris 10 introduced a facility that aids here, namely SMF, many of our customers simply haven't yet taken the time to take advantage of this - proceeding with logic that, while functional, without further analysis has an appearance of not being optimal in terms of taking advantage of all the niceties bundled in Solaris 11 at no extra cost. When looking at Solaris 11, we recognize that one of the vehicles that bridges the gap between getting the operating system image payload delivered, and the customized banking software installed, is a notion of a First Boot script.  I had a working example of this at one of the Oracle OpenWorld sessions a few years ago - we've since improved our documentation and have introduced sections where this is described in better detail.   If you're looking at this for the first time and you've not worked with IPS and SMF previously, you might get the sense that the tasks are daunting.   There is a set of technologies involved that are jointly engineered in order to make the process reliable, predictable and extensible. As you go down the path of writing your first boot script, you'll be faced with a need to wrap it into a SMF service and then packaged into a IPS package. The IPS package would then need to be placed onto your IPS repository, in order to subsequently be made available to all of your AI (Automated Install) clients (i.e. the systems that you're installing Solaris and your software onto).     With this blog post, I wanted to create a single place that outlines the entire process (simplistically), and provide a hint of how a good old "at" command may make the requirement of forcing an initial reboot handy. The syntax and references to commands here is based on running this on a version of Solaris 11 that has been updated since its initial release in 2011 (i.e. I am writing this on Solaris 11.1) Assuming you've built an AI server (see this How To article for an example), you might be asking yourself: "Ok, I've got some logic that I need executed AFTER Solaris is deployed and I need my own little script that would make that happen. How do I go about hooking that script into the Solaris 11 AI framework?"  You might start here, in Chapter 13 of the "Installing Oracle Solaris 11.1 Systems" guide, which talks about "Running a Custom Script During First Boot".  And as you do, you'll be confronted with command that might be unfamiliar to you if you're new to Solaris 11, like our dear new friend: svcbundle svcbundle is an aide to creating manifests and profiles.  It is awesome, but don't let its awesomeness overwhelm you. (See this How To article by my colleague Glynn Foster for a nice working example).  In order to get your script's logic integrated into the Solaris 11 deployment process, you need to wrap your (shell) script into 2 manifests -  a SMF service manifest and a IPS package manifest.  ....and if you're new to XML, well then -- buckle up We have some examples of small first boot scripts shown here, as templates to build upon. Necessary structure of the script, particularly in leveraging SMF interfaces, is key. I won't go into that here as that is covered nicely in the doc link above.    Let's say your script ends up looking like this (btw: if things appear to be cut-off in your browser, just select them, copy and paste into your editor and it'll be grabbed - the source gets captured eventhough the browser may not render it "correctly" - ah, computers). #!/bin/sh # Load SMF shell support definitions . /lib/svc/share/smf_include.sh # If nothing to do, exit with temporary disable completed=`svcprop -p config/completed site/first-boot-script-svc:default` [ "${completed}" = "true" ] && \ smf_method_exit $SMF_EXIT_TEMP_DISABLE completed "Configuration completed" # Obtain the active BE name from beadm: The active BE on reboot has an R in # the third column of 'beadm list' output. Its name is in column one. bename=`beadm list -Hd|nawk -F ';' '$3 ~ /R/ {print $1}'` beadm create ${bename}.orig echo "Original boot environment saved as ${bename}.orig" # ---- Place your one-time configuration tasks here ---- # For example, if you have to pull some files from your own pre-existing system: /usr/bin/wget -P /var/tmp/ $PULL_DOWN_ADDITIONAL_SCRIPTS_FROM_A_CORPORATE_SYSTEM /usr/bin/chmod 755 /var/tmp/$SCRIPTS_THAT_GOT_PULLED_DOWN_IN_STEP_ABOVE # Clearly the above 2 lines represent some logic that you'd have to customize to fit your needs. # # Perhaps additional things you may want to do here might be of use, like # (gasp!) configuring ssh server for root login and X11 forwarding (for testing), and the like... # # Oh and by the way, after we're done executing all of our proprietary scripts we need to reboot # the system in accordance with our operational software requirements to ensure all layered bits # get initialized properly and pull-in their own modules and components in the right sequence, # subsequently. # We need to set a "time bomb" reboot, that would take place upon completion of this script. # We already know that *this* script depends on multi-user-server SMF milestone, so it should be # safe for us to schedule a reboot for 5 minutes from now. The "at" job get scheduled in the queue # while our little script continues thru the rest of the logic. /usr/bin/at now + 5 minutes <<REBOOT /usr/bin/sync /usr/sbin/reboot REBOOT # ---- End of your customizations ---- # Record that this script's work is done svccfg -s site/first-boot-script-svc:default setprop config/completed = true svcadm refresh site/first-boot-script-svc:default smf_method_exit $SMF_EXIT_TEMP_DISABLE method_completed "Configuration completed"  ...and you're happy with it and are ready to move on. Where do you go and what do you do? The next step is creating the IPS package for your script. Since running the logic of your script constitutes a service, you need to create a service manifest. This is described here, in the middle of Chapter 13 of "Creating an IPS package for the script and service".  Assuming the name of your shell script is first-boot-script.sh, you could end up doing the following: $ cd some_working_directory_for_this_project$ mkdir -p proto/lib/svc/manifest/site$ mkdir -p proto/opt/site $ cp first-boot-script.sh proto/opt/site  Then you would create the service manifest  file like so: $ svcbundle -s service-name=site/first-boot-script-svc \ -s start-method=/opt/site/first-boot-script.sh \ -s instance-property=config:completed:boolean:false -o \ first-boot-script-svc-manifest.xml   ...as described here, and place it into the directory hierarchy above. But before you place it into the directory, make sure to inspect the manifest and adjust the appropriate service dependencies.  That is to say, you want to properly specify what milestone should be reached before your service runs.  There's a <dependency> section that looks like this, before you modify it: <dependency restart_on="none" type="service" name="multi_user_dependency" grouping="require_all"> <service_fmri value="svc:/milestone/multi-user"/>  </dependency>  So if you'd like to have your service run AFTER the multi-user-server milestone has been reached (i.e. later, as multi-user-server has more dependencies then multi-user and our intent to reboot the system may have significant ramifications if done prematurely), you would modify that section to read:  <dependency restart_on="none" type="service" name="multi_user_server_dependency" grouping="require_all"> <service_fmri value="svc:/milestone/multi-user-server"/>  </dependency> Save the file and validate it: $ svccfg validate first-boot-script-svc-manifest.xml Assuming there are no errors returned, copy the file over into the directory hierarchy: $ cp first-boot-script-svc-manifest.xml proto/lib/svc/manifest/site Now that we've created the service manifest (.xml), create the package manifest (.p5m) file named: first-boot-script.p5m.  Populate it as follows: set name=pkg.fmri value=first-boot-script-AT-1-DOT-0,5.11-0 set name=pkg.summary value="AI first-boot script" set name=pkg.description value="Script that runs at first boot after AI installation" set name=info.classification value=\ "org.opensolaris.category.2008:System/Administration and Configuration" file lib/svc/manifest/site/first-boot-script-svc-manifest.xml \ path=lib/svc/manifest/site/first-boot-script-svc-manifest.xml owner=root \ group=sys mode=0444 dir path=opt/site owner=root group=sys mode=0755 file opt/site/first-boot-script.sh path=opt/site/first-boot-script.sh \ owner=root group=sys mode=0555 Now we are going to publish this package into a IPS repository. If you don't have one yet, don't worry. You have 2 choices: You can either  publish this package into your mirror of the Oracle Solaris IPS repo or create your own customized repo.  The best practice is to create your own customized repo, leaving your mirror of the Oracle Solaris IPS repo untouched.  From this point, you have 2 choices as well - you can either create a repo that will be accessible by your clients via HTTP or via NFS.  Since HTTP is how the default Solaris repo is accessed, we'll go with HTTP for your own IPS repo.   This nice and comprehensive How To by Albert White describes how to create multiple internal IPS repos for Solaris 11. We'll zero in on the basic elements for our needs here: We'll create the IPS repo directory structure hanging off a separate ZFS file system, and we'll tie it into an instance of pkg.depotd. We do this because we want our IPS repo to be accessible to our AI clients through HTTP, and the pkg.depotd SMF service bundled in Solaris 11 can help us do this. We proceed as follows: # zfs create rpool/export/MyIPSrepo # pkgrepo create /export/MyIPSrepo # svccfg -s pkg/server add MyIPSrepo # svccfg -s pkg/server:MyIPSrepo addpg pkg application # svccfg -s pkg/server:MyIPSrepo setprop pkg/port=10081 # svccfg -s pkg/server:MyIPSrepo setprop pkg/inst_root=/export/MyIPSrepo # svccfg -s pkg/server:MyIPSrepo addpg general framework # svccfg -s pkg/server:MyIPSrepo addpropvalue general/complete astring: MyIPSrepo # svccfg -s pkg/server:MyIPSrepo addpropvalue general/enabled boolean: true # svccfg -s pkg/server:MyIPSrepo setprop pkg/readonly=true # svccfg -s pkg/server:MyIPSrepo setprop pkg/proxy_base = astring: http://your_internal_websrvr/MyIPSrepo # svccfg -s pkg/server:MyIPSrepo setprop pkg/threads = 200 # svcadm refresh application/pkg/server:MyIPSrepo # svcadm enable application/pkg/server:MyIPSrepo Now that the IPS repo is created, we need to publish our package into it: # pkgsend publish -d ./proto -s /export/MyIPSrepo first-boot-script.p5m If you find yourself making changes to your script, remember to up-rev the version in the .p5m file (which is your IPS package manifest), and re-publish the IPS package. Next, you need to go to your AI install server (which might be the same machine) and modify the AI manifest to include a reference to your newly created package.  We do that by listing an additional publisher, which would look like this (replacing the IP address and port with your own, from the "svccfg" commands up above): <publisher name="firstboot"> <origin name="http://192.168.1.222:10081"/> </publisher>  Further down, in the  <software_data action="install">  section add: <name>pkg:/first-boot-script</name> Make sure to update your Automated Install service with the new AI manifest via installadm update-manifest command.  Don't forget to boot your client from the network to watch the entire process unfold and your script get tested.  Once the system makes the initial reboot, the first boot script will be executed and whatever logic you've specified in it should be executed, too, followed by a nice reboot. When the system comes up, your service should stay in a disabled state, as specified by the tailing lines of your SMF script - this is normal and should be left as is as it helps provide an auditing trail for you.   Because the reboot is quite a significant action for the system, you may want to add additional logic to the script that actually places and then checks for presence of certain lock files in order to avoid doing a reboot unnecessarily. You may also want to, alternatively, remove the SMF service entirely - if you're unsure of the potential for someone to try and accidentally enable that service -- eventhough its role in life is to only run once upon the system's first boot. That is how I spent a good chunk of my pre-Halloween time this week, hope yours was just as SPARCkly^H^H^H^H fun!    

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  • Optical SPDIF audio from motherboard not working with receiver

    - by simon b
    Hi, I hope someone can help; I can't get my SPDIF optical out working through my receiver and all the responses I can see on the web assume you have a sound card, while I settled for the (seemingly high end) sound on my motherboard (Asus P7P55D-E PRO), which appears to limit some of my options. My set-up is a "new out of the box" one and is: *Windows 7 PC (using PowerDVD10 for DVDs/Blurays and Windows media player for music) *Asus P7P55D-E PRO motherboard - has 8-channel audio TRS jacks and SPDIF optical and coaxial out *An old Yamaha receiver, whose only multi-channel input options are optical in and 6 channel RCA in. However, it still can handle DTS and DD *Boston Acoustic Soundware XS 5.1 speakers I've currently got the SPDIF optical out from the motherboard connected to the in on my receiver, have SPDIF enabled in the sound menu and the light is glowing red down the fibre. But I'm getting no sound at all. What I want is to be able to play DVDs/BluRays in 5.1 but also to be able to play music in multi-channel mode (even though I know this will be "fake" multichannel; it's more about where I sit in the room and my requirement to use the sub because the Boston is a satellite/sub set-up) My questions are: *Will optical work at all for multi-channel? THe latest posts I can see suggest it does but some people seem to say optical only outputs stereo. Whom to believe? *Even if it does work, I've read that I have to disable AC-3 decoding, or make various other changes, which don't seem to be possible without the menu options that a sound-card brings. Is the motherboard-only option just too inflexible? *Although my SPDIF device is enabled in the sound menu, it insists under "Jack information" that it is a "rear panel RCA jack", when of course it is not (both TOSLINK and rCA jacks do exist). Has the PC just forgotten that it has an optical? *I think I could relatively easily connect the 8-channel 3.5mm TRS jacks to my receiver 6-ch input jacks by way of TRS/RCA cables, but would that not stop me from being able to play music from media-player in multi-channel mode, as I'm not sure the motherboard can cope *Or do I need to bite the bullet and buy a sound-card? And if so, how can I be sure the one I get doesn't have the same problem? Any thoughts gratefully received, Cheers, simon

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  • DVD authoring software that supports multiple angles?

    - by RandomEngy
    I'm writing a DVD ripping app and I need to get some sources with multiple angles. Unfortunately, they seem to be rather hard to come by. I figured my best bet would be to author a simple DVD with a multi-angle title. Does anyone know of any software on Windows that lets you make multi-angle titles? Preferably free or trialware? I don't need it to be super-usable, just enough to make one DVD.

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  • Regex to parse a multiline HTML

    - by dreamer
    am trying to parse a multi-line html file using regex. HTML code: < td>Details< /td> < /tr> < tr class=d1> < td>uss_vod_translator< /td> Regex Expression: if ($line =~ m/Details<\/td>\s*<\/tr>\s*<tr\s*class=d1>\s*<td>(\w*)<\/td>/) { print "$1"; } I am using /s* (space) for multi-line, but it is not working. I searched about it, even used /\? for multi-line but that too did not work. Can any one please suggest me how to parse a multiline HTML?

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  • How do I synchronize access to shared memory in LynxOS/POSIX?

    - by GrahamS
    I am implementing two processes on a LynxOS SE (POSIX conformant) system that will communicate via shared memory. One process will act as a "producer" and the other a "consumer". In a multi-threaded system my approach to this would be to use a mutex and condvar (condition variable) pair, with the consumer waiting on the condvar (with pthread_cond_wait) and the producer signalling it (with pthread_cond_signal) when the shared memory is updated. How do I achieve this in a multi-process, rather than multi-threaded, architecture? Is there a LynxOS/POSIX way to create a condvar/mutex pair that can be used between processes? Or is some other synchronization mechanism more appropriate in this scenario?

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  • cakephp filter index pages according to foreign keys

    - by Marki
    Hi there, I'm pretty new to CakePHP and was missing a crucial feature not generated as scaffold: filtering. What do I have to do to provide dropdowns or multi-selects on the index pages for each field that is a (foreign) key, thereby allowing to filter the table ("OR" inside multi-select, "AND" between different multi-selects, if any)? From what my websearch has shown me there are many more people trying to accomplish the same thing, although I couldn't find anything that would work for me because either they have text fields and do wildcard filtering, or the plugins they propose only work for 1.2 whereas i now started with 1.3 etc. etc. Can someone alleviate the confusion and maybe present some working code or direct me to the definitive guide[tm] where this matter has been solved? Thx

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  • Problem getting IM information from an ABRecord

    - by bend0r
    Hello, I'm trying to get the IM account information from existing contacts (adressbook) on iPhone. I walk through the contacts and I get the contacts which have an entry in IM but I can't read the jabber-address. abArray = (NSArray *)ABAddressBookCopyArrayOfAllPeople(ABAddressBookCreate()); for(int i=0 ; i<[abArray count];i++) { ABRecordRef record = [abArray objectAtIndex:i]; ABMutableMultiValueRef multi = ABRecordCopyValue(record, kABPersonInstantMessageProperty); for(CFIndex x=0;x<ABMultiValueGetCount(multi);x++) { CFDictionaryRef dict = ABMultiValueCopyValueAtIndex(multi, x); CFStringRef jabber = CFDictionaryGetValue(dict, kABPersonInstantMessageServiceJabber); if(CFDictionaryContainsKey(dict, kABPersonInstantMessageServiceJabber)) { NSLog(@"yes"); } else { NSLog(@"no"); } // only to make it possible to log to console NSString *jaab = (NSString *)jabber; NSLog(@"jabber adress: %@" , jaab); } CFRelease(dict); } } what I'm doing wrong?

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  • how to get latex to hyphenate a word that contains a dash ?

    - by Gyom
    In a latex document I'm writing, I get an overfull hbox warning because of the word "multi-disciplinary", which happens to be rendered at the end of a line. I can get rid of this particular warning by changing it into multi-discipli\-nary, but the same problem will happen elsewhere, since this word is used a lot in the paper. I'd like to use the \hyphenation{} command instead, but obviously my tentative \hyphenation{multi-disci-pli-na-ry} does not work, because it does not understand the first dash correctly. What incantation do I need to get correct indentation in a word that already contains a dash ? Bonus question: where could I have found the answer to that question myself ?

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  • How should I implement simple caches with concurrency on Redis?

    - by solublefish
    Background I have a 2-tier web service - just my app server and an RDBMS. I want to move to a pool of identical app servers behind a load balancer. I currently cache a bunch of objects in-process. I hope to move them to a shared Redis. I have a dozen or so caches of simple, small-sized business objects. For example, I have a set of Foos. Each Foo has a unique FooId and an OwnerId. One "owner" may own multiple Foos. In a traditional RDBMS this is just a table with an index on the PK FooId and one on OwnerId. I'm caching this in one process simply: Dictionary<int,Foo> _cacheFooById; Dictionary<int,HashSet<int>> _indexFooIdsByOwnerId; Reads come straight from here, and writes go here and to the RDBMS. I usually have this invariant: "For a given group [say by OwnerId], the whole group is in cache or none of it is." So when I cache miss on a Foo, I pull that Foo and all the owner's other Foos from the RDBMS. Updates make sure to keep the index up to date and respect the invariant. When an owner calls GetMyFoos I never have to worry that some are cached and some aren't. What I did already The first/simplest answer seems to be to use plain ol' SET and GET with a composite key and json value: SET( "ServiceCache:Foo:" + theFoo.Id, JsonSerialize(theFoo)); I later decided I liked: HSET( "ServiceCache:Foo", theFoo.FooId, JsonSerialize(theFoo)); That lets me get all the values in one cache as HVALS. It also felt right - I'm literally moving hashtables to Redis, so perhaps my top-level items should be hashes. This works to first order. If my high-level code is like: UpdateCache(myFoo); AddToIndex(myFoo); That translates into: HSET ("ServiceCache:Foo", theFoo.FooId, JsonSerialize(theFoo)); var myFoos = JsonDeserialize( HGET ("ServiceCache:FooIndex", theFoo.OwnerId) ); myFoos.Add(theFoo.OwnerId); HSET ("ServiceCache:FooIndex", theFoo.OwnerId, JsonSerialize(myFoos)); However, this is broken in two ways. Two concurrent operations can read/modify/write at the same time. The latter "wins" the final HSET and the former's index update is lost. Another operation could read the index in between the first and second lines. It would miss a Foo that it should find. So how do I index properly? I think I could use a Redis set instead of a json-encoded value for the index. That would solve part of the problem since the "add-to-index-if-not-already-present" would be atomic. I also read about using MULTI as a "transaction" but it doesn't seem like it does what I want. Am I right that I can't really MULTI; HGET; {update}; HSET; EXEC since it doesn't even do the HGET before I issue the EXEC? I also read about using WATCH and MULTI for optimistic concurrency, then retrying on failure. But WATCH only works on top-level keys. So it's back to SET/GET instead of HSET/HGET. And now I need a new index-like-thing to support getting all the values in a given cache. If I understand it right, I can combine all these things to do the job. Something like: while(!succeeded) { WATCH( "ServiceCache:Foo:" + theFoo.FooId ); WATCH( "ServiceCache:FooIndexByOwner:" + theFoo.OwnerId ); WATCH( "ServiceCache:FooIndexAll" ); MULTI(); SET ("ServiceCache:Foo:" + theFoo.FooId, JsonSerialize(theFoo)); SADD ("ServiceCache:FooIndexByOwner:" + theFoo.OwnerId, theFoo.FooId); SADD ("ServiceCache:FooIndexAll", theFoo.FooId); EXEC(); //TODO somehow set succeeded properly } Finally I'd have to translate this pseudocode into real code depending how my client library uses WATCH/MULTI/EXEC; it looks like they need some sort of context to hook them together. All in all this seems like a lot of complexity for what has to be a very common case; I can't help but think there's a better, smarter, Redis-ish way to do things that I'm just not seeing. How do I lock properly? Even if I had no indexes, there's still a (probably rare) race condition. A: HGET - cache miss B: HGET - cache miss A: SELECT B: SELECT A: HSET C: HGET - cache hit C: UPDATE C: HSET B: HSET ** this is stale data that's clobbering C's update. Note that C could just be a really-fast A. Again I think WATCH, MULTI, retry would work, but... ick. I know in some places people use special Redis keys as locks for other objects. Is that a reasonable approach here? Should those be top-level keys like ServiceCache:FooLocks:{Id} or ServiceCache:Locks:Foo:{Id}? Or make a separate hash for them - ServiceCache:Locks with subkeys Foo:{Id}, or ServiceCache:Locks:Foo with subkeys {Id} ? How would I work around abandoned locks, say if a transaction (or a whole server) crashes while "holding" the lock?

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  • How is this relation in 4th normal form? Is the dependency trivial?

    - by squ
    I have a question that concerns multi value dependency. The relation looks like this: R(A,B) with A -->> B (A multi value determines B) I've been told that this relation is in 4th normal form, but I don't really se how. I know that if the multi value dependency is trivial, then it doesn't violate the 4th normal form. But is this trivial? It would be trivial if it, for example, looked like this: {A,B} -->> B But the first dependency example shouldn't be trivial. The other rule for 4th NF says that A in this case needs to be a super key of the relation, but it isn't. As far as I can tell, A isn't a super key, since {A,B} is needed to identify a tuple. So the question is, why is this in 4th normal form? It seems to be violating both of the rules.

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  • BizTalk 2009 - Naming Guidelines

    - by StuartBrierley
    The following is effectively a repost of the BizTalk 2004 naming guidlines that I have previously detailed.  I have posted these again for completeness under BizTalk 2009 and to allow an element of separation in case I find some reason to amend these for BizTalk 2009. These guidlines should be universal across any version of BizTalk you may wish to apply them to. General Rules All names should be named with a Pascal convention. Project Namespaces For message schemas: [CompanyName].XML.Schemas.[FunctionalName]* Examples:  ABC.XML.Schemas.Underwriting DEF.XML.Schemas.MarshmellowTradingExchange * Donates potential for multiple levels of functional name, such as Underwriting.Dictionary.Valuation For web services: [CompanyName].Web.Services.[FunctionalName] Examples: ABC.Web.Services.OrderJellyBeans For the main BizTalk Projects: [CompanyName].BizTalk.[AssemblyType].[FunctionalName]* Examples: ABC.BizTalk.Mappings.Underwriting ABC.BizTalk.Orchestrations.Underwriting * Donates potential for multiple levels of functional name, such as Mappings.Underwriting.Valuations Assemblies BizTalk Assembly names should match the associated Project Namespace, such as ABC.BizTalk.Mappings.Underwriting. This pertains to the formal assembly name and the DLL name. The Solution name should take the name of the main project within the solution, and also therefore the namespace for that project. Although long names such as this can be unwieldy to work with, the benefits of having the full scope available when the assemblies are installed on the target server are generally judged to outweigh this inconvenience. Messaging Artifacts Artifact Standard Notes Example Schema <DescriptiveName>.xsd   .NET Type name should match, without file extension.    .NET Namespace will likely match assembly name. PurchaseOrderAcknowledge_FF.xsd  or FNMA100330_FF.xsd Property Schema <DescriptiveName>.xsd Should be named to reflect possible common usage across multiple schemas  IspecMessagePropertySchema.xsd UnderwritingOrchestrationKeys.xsd Map <SourceSchema>2<DestinationSchema>.btm Exceptions to this may be made where the source and destination schemas share the majority of the name, such as in mainframe web service maps InstructionResponse2CustomEmailRequest.btm (exception example) AccountCustomerAddressSummaryRequest2MainframeRequest.btm Orchestration <DescriptiveName>.odx   GetValuationReports.odx SendMTEDecisionResponse.odx Send/Receive Pipeline <DescriptiveName>.btp   ValidatingXMLReceivePipeline.btp FlatFileAssembler.btp Receive Port A plainly worded phrase that will clearly explain the function.    FraudPreventionServices LetterProcessing   Receive Location A plainly worded phrase that will clearly explain the function.  ? Do we want to include the transport type here ? Arrears Web Service Send Port Group A plainly worded phrase that will clearly explain the function.   Customer Updates Send Port A plainly worded phrase that will clearly explain the function.    ABCProductUpdater LogLendingPolicyOutput Parties A meaningful name for a Trading Partner. If dealing with multiple entities within a Trading Partner organization, the Organization name could be used as a prefix.   Roles A meaningful name for the role that a Trading Partner plays.     Orchestration Workflow Shapes Shape Standard Notes Example Scopes <DescriptionOfContainedWork> or <DescOfcontainedWork><TxType>   Including info about transaction type may be appropriate in some situations where it adds significant documentation value to the diagram. HandleReportResponse         Receive Receive<MessageName> Typically, MessageName will be the same as the name of the message variable that is being received “into”. ReceiveReportResponse Send Send<MessageName> Typically, MessageName will be the same as the name of the message variable that is being sent. SendValuationDetailsRequest Expression <DescriptionOfEffect> Expression shapes should be named to describe the net effect of the expression, similar to naming a method.  The exception to this is the case where the expression is interacting with an external .NET component to perform a function that overlaps with existing BizTalk functionality – use closest BizTalk shape for this case. CreatePrintXML Decide <DescriptionOfDecision> A description of what will be decided in the “if” branch Report Type? Perform MF Save? If-Branch <DescriptionOfDecision> A (potentially abbreviated) description of what is being decided Mortgage Valuation Yes Else-Branch Else Else-branch shapes should always be named “Else” Else Construct Message (Assign) Create<Message> (for Construct)     <ExpressionDescription> (for expression) If a Construct shape contains a message assignment, it should be prefixed with “Create” followed by an abbreviated name of the message being assigned.    The actual message assignment shape contained should be named to describe the expression that is contained. CreateReportDataMV   which contains expression: ExtractReportData Construct Message (Transform) Create<Message> (for Construct)   <SourceSchema>2<DestSchema> (for transform) If a Construct shape contains a message transform, it should be prefixed with “Create” followed by an abbreviated name of the message being assigned.   The actual message transform shape contained should generally be named the same as the called map.  CreateReportDataMV   which contains transform: ReportDataMV2ReportDataMV                 Construct Message (containing multiple shapes)   If a Construct Message shape uses multiple assignments or transforms, the overall shape should be named to communicate the net effect, using no prefix.     Call/Start Orchestration Call<OrchestrationName>   Start<OrchestrationName>     Throw Throw<ExceptionType> The corresponding variable name for the exception type should (often) be the same name as the exception type, only camel-cased. ThrowRuleException, which references the “ruleException” variable.     Parallel <DescriptionOfParallelWork> Parallel shapes should be named by a description of what work will be done in parallel   Delay <DescriptionOfWhatWaitingFor> Delay shapes should be named by a description of what is being waited for.  POAcknowledgeTimeout Listen <DescriptionOfOutcomes> Listen shapes should be named by a description that captures (to the degree possible) all the branches of the Listen shape POAckOrTimeout FirstShippingBid Loop <DescriptionOfLoop> A (potentially abbreviated) description of what the loop is. ForEachValuationReport WhileErrorFlagTrue Role Link   See “Roles” in messaging naming conventions above.   Suspend <ReasonDescription> Describe what action an administrator must take to resume the orchestration.  More detail can be passed to error property – and should include what should be done by the administrator before resuming the orchestration. ReEstablishCreditLink Terminate <ReasonDescription> Describe why the orchestration terminated.  More detail can be passed to error property. TimeoutsExpired Call Rules Call<PolicyName> The policy name may need to be abbreviated. CallLendingPolicy Compensate Compensate or Compensate<TxName> If the shape compensates nested transactions, names should be suffixed with the name of the nested transaction – otherwise it should simple be Compensate. CompensateTransferFunds Orchestration Types Type Standard Notes Example Multi-Part Message Types <LogicalDocumentType>   Multi-part types encapsulate multiple parts.  The WSDL spec indicates “parts are a flexible mechanism for describing the logical abstract content of a message.”  The name of the multi-part type should correspond to the “logical” document type, i.e. what the sum of the parts describes. InvoiceReceipt   (which might encapsulate an invoice acknowledgement and a payment voucher.) Multi-Part Messsage Part <SchemaNameOfPart> Should be named (most often) simply for the schema (or simple type) associated with the part. InvoiceHeader Messages <SchemaName> or <MuliPartMessageTypeName> Should be named based on the corresponding schema type or multi-part message type.  If there is more than one variable of a type, name for its use within the orchestration. ReportDataMV UpdatedReportDataMV Variables <DescriptiveName>   TargetFilePath StringProcessor Port Types <FunctionDescription>PortType Should be named to suggest the nature of an endpoint, with pascal casing and suffixed with “PortType”.   If there will be more than one Port for a Port Type, the Port Type should be named according to the abstract service supplied.   The WSDL spec indicates port types are “a named set of abstract operations and the abstract messages involved” that also encapsulates the message pattern (i.e. one-way, request-response, solicit-response) that all operations on the port type adhere to. ReceiveReportResponsePortType  or CallEAEPortType (This is a two way port, so Receove or Send alone would not be appropriate.  Could have been ProcessEAERequestPortType etc....) Ports <FunctionDescription>Port Should be named to suggest a grouping of functionality, with pascal casing and suffixed with “Port.”  ReceiveReportResponsePort CallEAEPort Correlation types <DescriptiveName> Should be named based on the logical name of what is being used to correlate.  PurchaseOrderNumber Correlation sets <DescriptiveName> Should be named based on the corresponding correlation type.  If there is more than one, it should be named to reflect its specific purpose within the orchestration.   PurchaseOrderNumber Orchestration parameters <DescriptiveName> Should be named to match the caller’s names for the corresponding variables where appropriate.

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  • Silverlight Cream for December 28, 2010 -- #1017

    - by Dave Campbell
    In this Issue: Davide Zordan, Alex Golesh, Michael S. Scherotter, Andrej Tozon, Alex Knight, Jeff Blankenburg(-2-), Jeremy Likness, and Laurent Bugnion. Above the Fold: Silverlight: "My “What’s new in Silverlight 4 demo” app" Andrej Tozon WP7: "Taking a screenshot from within a Silverlight #WP7 application" Laurent Bugnion Expression Blend: "PathListBox: getting started" Alex Knight Shoutouts: If you haven't seen this SurfCube app demo on YouTube yet... check it out now: SurfCube V1.0 Windows Phone 7 Browser Want to get a free WP7 class from Shawn Wildermuth? Check this out: Webinar: Writing your first Windows Phone 7 Application Koen Zwikstra announed the next preview of his great tool: Silverlight Spy Preview 2 From SilverlightCream.com: Using the Multi-Touch Behavior in a Windows Phone 7 Multi-Page application Davide Zordan has a post up responding to questions he receives about multi-touch on WP7 in applications spanning more than one page. Silverlight for Windows Phone 7 Quick Tip: Fix missing icons while using DatePicker/TimePicker controls Alex Golesh discusses the use of the DatePicker control from the WP7 toolkit and found an unpleasant surprise associated with the Done/Cancel icons in the ApplicationBar, and has a solution for us. Updated SMF Thumbnail Scrubbing Sample Code Michael S. Scherotter has a post up about an update he's done to Silverlight 4 of code that allows thumbnail views of a video while 'scrubbing' ... don't know what that is? read the post :) My “What’s new in Silverlight 4 demo” app Andrej Tozon admits he's a little behind with this post, but as he points out, it might be a good time to review Silverlight 4 features, on the eve of 5. PathListBox: getting started One half the Knight team -- Alex Knight this time, has the first post of a series on the PathListBox up ... some real Expression Blend goodness. What I Learned in WP7 – Issue #9 Two more from Jeff Blankenburg today, in his number 9, he starts off demonstrating passing data between pages when navigating and fnishes up with some excellent info for submitting apps to the marketplace. What I Learned in WP7 – #Issue 10 Jeff Blankenburg's number 10 elaborates on the query string data he discussed in number 9. Using Sterling in Windows Phone 7 Applications Who better than the author?? Jeremy Likness has an end-to-end WP7/Sterling app up on his blog... begin with downloading Sterling, discuss what's needed to support Tombstoning, even custom serialization. Taking a screenshot from within a Silverlight #WP7 application Laurent Bugnion has a post up describing something people have been looking for: getting a screenshot of a WP7 application's page. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Using Amazon S3/Cloudfront and Encoding.com to deliver web video – step by step for iPhone/iPod/iPad

    - by joelvarty
      The Amazon AWS newsletter for May 2010 had a great link in it to this article by encoding.com on how you can use they service to encode your video for multi-format, multi-bandwidth streaming to many devices, including iPhone, iPad, and Flash with H264.   This looks like it doesn’t actually take advantage of CloudFront streaming, but merely splits your encoded files into the available chunks and includes all of the M3U8 files that point to the different bitrates and such.   This looks like a pretty sweet service in general, especially since they seem to have an API as well, so that may be very useful to those of you out there looking to host video. more later – joel

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  • Installed Perl DBI Module Can't Be Found

    - by Russell C.
    I'm trying to setup a Perl development environment on my Mac laptop and have been having a really hard time getting it working. I thought I had everything configured correctly but when I try to run a sample script it is reporting errors with the DBI module and can't access the DB. Here is what is reported in the Apache error logs: [Fri Apr 30 23:11:33 2010] [error] [client 127.0.0.1] Can't locate DBI.pm in @INC (@INC contains: /Library/Perl/Updates/5.10.0/darwin-thread-multi-2level /Library/Perl/Updates/5.10.0 /System/Library/Perl/5.10.0/darwin-thread-multi-2level /System/Library/Perl/5.10.0 /Library/Perl/5.10.0/darwin-thread-multi-2level /Library/Perl/5.10.0 /Network/Library/Perl/5.10.0/darwin-thread-multi-2level /Network/Library/Perl/5.10.0 /Network/Library/Perl /System/Library/Perl/Extras/5.10.0/darwin-thread-multi-2level /System/Library/Perl/Extras/5.10.0 .) at main.pm line 5. I downloaded and installed both modules manually to work with MAMP using the following commands as specified in this forum post: For DBI 1. cd /Library/Perl/DBI-1.611 2. sudo Perl Makefile.PL 3. sudo make 4. sudo make install For DBD 1. cd /Library/Perl/DBD-mysql-4.014 2. sudo Perl Makefile.PL --mysql_config=/Applications/MAMP/Library/bin/mysql_config 3. sudo make 4. sudo make install What I noticed while running the above commands is that the files seems to be getting installed in the '/opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/' directory which doesn't seem to be one of the search directories that Apache mentions in the error at the beginning of this post. Here is what I'm seeing during the install: $ sudo make install Files found in blib/arch: installing files in blib/lib into architecture dependent library tree Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/DBI.bundle Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/dbipport.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/DBIXS.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/dbixs_rev.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/Driver.xst Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/Driver_xst.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/TASKS.pod Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBD/DBM.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBD/File.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBD/Gofer.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/Changes.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/DBD.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/Profile.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/ProxyServer.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/PurePerl.pm Installing /opt/local/share/man/man3/DBD::DBM.3pm Installing /opt/local/share/man/man3/DBD::File.3pm Installing /opt/local/share/man/man3/DBD::Gofer.3pm Installing /opt/local/share/man/man3/DBI.3pm Installing /opt/local/share/man/man3/DBI::DBD.3pm Installing /opt/local/share/man/man3/DBI::Profile.3pm Installing /opt/local/share/man/man3/DBI::ProxyServer.3pm Installing /opt/local/share/man/man3/DBI::PurePerl.3pm Installing /opt/local/share/man/man3/TASKS.3pm Installing /opt/local/bin/dbiprof Installing /opt/local/bin/dbiproxy Writing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/.packlist Appending installation info to /opt/local/lib/perl5/5.8.9/darwin-2level/perllocal.pod My question is, what am I doing wrong and how can I either 1) Get Apache to look in the right directory where the DBD & DBI modules are installed or 2) Update the way I'm installing the module to install them into one of the search directories. I honestly don't know what option makes more sense and could use guidance on that as well. As you can probably tell I'm pretty lost at the moment. Please help!!!

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  • How can I install Perl's DBI on Mac OS X so Apache can find it?

    - by Russell C.
    I'm trying to setup a Perl development environment on my Mac laptop and have been having a really hard time getting it working. I thought I had everything configured correctly but when I try to run a sample script it is reporting errors with the DBI module and can't access the DB. Here is what is reported in the Apache error logs: [Fri Apr 30 23:11:33 2010] [error] [client 127.0.0.1] Can't locate DBI.pm in @INC (@INC contains: /Library/Perl/Updates/5.10.0/darwin-thread-multi-2level /Library/Perl/Updates/5.10.0 /System/Library/Perl/5.10.0/darwin-thread-multi-2level /System/Library/Perl/5.10.0 /Library/Perl/5.10.0/darwin-thread-multi-2level /Library/Perl/5.10.0 /Network/Library/Perl/5.10.0/darwin-thread-multi-2level /Network/Library/Perl/5.10.0 /Network/Library/Perl /System/Library/Perl/Extras/5.10.0/darwin-thread-multi-2level /System/Library/Perl/Extras/5.10.0 .) at main.pm line 5. I downloaded and installed both modules manually to work with MAMP using the following commands as specified in this forum post: For DBI 1. cd /Library/Perl/DBI-1.611 2. sudo Perl Makefile.PL 3. sudo make 4. sudo make install For DBD 1. cd /Library/Perl/DBD-mysql-4.014 2. sudo Perl Makefile.PL --mysql_config=/Applications/MAMP/Library/bin/mysql_config 3. sudo make 4. sudo make install What I noticed while running the above commands is that the files seems to be getting installed in the '/opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/' directory which doesn't seem to be one of the search directories that Apache mentions in the error at the beginning of this post. Here is what I'm seeing during the install: $ sudo make install Files found in blib/arch: installing files in blib/lib into architecture dependent library tree Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/DBI.bundle Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/dbipport.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/DBIXS.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/dbixs_rev.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/Driver.xst Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/Driver_xst.h Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/TASKS.pod Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBD/DBM.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBD/File.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBD/Gofer.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/Changes.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/DBD.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/Profile.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/ProxyServer.pm Installing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/DBI/PurePerl.pm Installing /opt/local/share/man/man3/DBD::DBM.3pm Installing /opt/local/share/man/man3/DBD::File.3pm Installing /opt/local/share/man/man3/DBD::Gofer.3pm Installing /opt/local/share/man/man3/DBI.3pm Installing /opt/local/share/man/man3/DBI::DBD.3pm Installing /opt/local/share/man/man3/DBI::Profile.3pm Installing /opt/local/share/man/man3/DBI::ProxyServer.3pm Installing /opt/local/share/man/man3/DBI::PurePerl.3pm Installing /opt/local/share/man/man3/TASKS.3pm Installing /opt/local/bin/dbiprof Installing /opt/local/bin/dbiproxy Writing /opt/local/lib/perl5/site_perl/5.8.9/darwin-2level/auto/DBI/.packlist Appending installation info to /opt/local/lib/perl5/5.8.9/darwin-2level/perllocal.pod My question is, what am I doing wrong and how can I either 1) Get Apache to look in the right directory where the DBD & DBI modules are installed or 2) Update the way I'm installing the module to install them into one of the search directories. I honestly don't know what option makes more sense and could use guidance on that as well. As you can probably tell I'm pretty lost at the moment. Please help!!! Thanks in advance.

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