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• How to create a formatted localized string?

  - by mystify

  I have a localized string which needs to take a few variables. However, in localization it is important that the order of the variables can change from language to language. So this is not a good idea: NSString *text = NSLocalizedString(@"My birthday is at %@ %@ in %@", nil); In some languages some words come before others, while in others it's reverse. I lack of an good example at the moment. How would I provide NAMED variables in a formatted string? Is there any way to do it without some heavy self-made string replacements? Even some numbered variables like {%@1}, {%@2}, and so on would be sufficient... is there a solution?

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• Program structure in long running data processing python script

  - by fmark

  For my current job I am writing some long-running (think hours to days) scripts that do CPU intensive data-processing. The program flow is very simple - it proceeds into the main loop, completes the main loop, saves output and terminates: The basic structure of my programs tends to be like so: <import statements> <constant declarations> <misc function declarations> def main(): for blah in blahs(): <lots of local variables> <lots of tightly coupled computation> for something in somethings(): <lots more local variables> <lots more computation> <etc., etc.> <save results> if __name__ == "__main__": main() This gets unmanageable quickly, so I want to refactor it into something more manageable. I want to make this more maintainable, without sacrificing execution speed. Each chuck of code relies on a large number of variables however, so refactoring parts of the computation out to functions would make parameters list grow out of hand very quickly. Should I put this sort of code into a python class, and change the local variables into class variables? It doesn't make a great deal of sense tp me conceptually to turn the program into a class, as the class would never be reused, and only one instance would ever be created per instance. What is the best practice structure for this kind of program? I am using python but the question is relatively language-agnostic, assuming a modern object-oriented language features.

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• Registered Symbol Problem with Flash Mailto Link

  - by Nick

  The problem I'm having is an extra  Chracter being added before the ® symbol in the body of an email created from a mailto: link in flash. This only happens on the PC in MS Outlook Instead of: MasterCard®! It shows up as MasterCard®! The code in flash AS3: var req = new URLRequest("mailto:"); var variables = new URLVariables(); variables.body="Blah Blah Blah MasterCard®!"; variables.subject="Make some music!"; req.data = variables; req.method = URLRequestMethod.GET; addEventListener(MouseEvent.CLICK, onClick); function onClick(e:MouseEvent) { navigateToURL(req, "_self"); } } This works fine on the mac with mac mail.

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• Random forests for short texts

  - by Jasie

  Hi all, I've been reading about Random Forests (1,2) because I think it'd be really cool to be able to classify a set of 1,000 sentences into pre-defined categories. I'm wondering if someone can explain to me the algorithm better, I think the papers are a bit dense. Here's the gist from 1: Overview We assume that the user knows about the construction of single classification trees. Random Forests grows many classification trees. To classify a new object from an input vector, put the input vector down each of the trees in the forest. Each tree gives a classification, and we say the tree "votes" for that class. The forest chooses the classification having the most votes (over all the trees in the forest). Each tree is grown as follows: If the number of cases in the training set is N, sample N cases at random - but with replacement, from the original data. This sample will be the training set for growing the tree. If there are M input variables, a number m « M is specified such that at each node, m variables are selected at random out of the M and the best split on these m is used to split the node. The value of m is held constant during the forest growing. Each tree is grown to the largest extent possible. There is no pruning. So, does this look right? I'd have N = 1,000 training cases (sentences), M = 100 variables (let's say, there are only 100 unique words across all sentences), so the input vector is a bit vector of length 100 corresponding to each word. I randomly sample N = 1000 cases at random (with replacement) to build trees from. I pick some small number of input variables m « M, let's say 10, to build a tree off of. Do I build tree nodes randomly, using all m input variables? How many classification trees do I build? Thanks for the help!

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• Iterating over two arrays at a time in Javascript

  - by Ankur

  I want to iterate over two arrays at the same time, as the values for any given index i in array A corresponds to the value in array B. I am currently using this code, and getting 'undefined' when I call queryPredicates[i] or queryObjects[i], I know my array is populated as I print out the array prior to calling this, I haven't put all the other code in as it might be confusing, but if you think the problem is not evident from this I will edit the question: function getObjectCount(){ variables = queryPredicates.length; //the number of variables is found by the length of the arrays - they should both be of the same length queryString="count="+variables; for(var i=1; i<=variables;i++){ alert(queryPredicates[i]); alert(queryObjects[i]); } Thanks

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• Flex Air HTMLLoader blank pop up window when flash content is loaded

  - by user128938

  I have a flex Air program that loads external content with the HTMLLoader. Now for some reason whenever I load a page that has any flash content a blank system window pops up outside of my program. It's completely blank, all white with min, max and close buttons. If I close it any flash content I loaded stops working. For the life of my I can't figure out what's happening and there's no messages in the console and no title for the window. Does anyone have any ideas? I appreciate any help you can give. Here's the code I'm using: private var webPage:HTMLLoader; private function registerEvents():void { this.addEventListener(gameLoadEvent.GAME_LOAD, gameLoad); //webPage = new HTMLLoader(); } //function called back from Game Command to load correct game private function gameLoad(event:Event):void { var gameEvent:gameLoadEvent = event as gameLoadEvent; loadgame(gameEvent.url, gameEvent.variables); } private function loadgame(url:String, variableString:String):void { DesktopModelLocator.getInstance().scaleX = 1; DesktopModelLocator.getInstance().scaleY = 1; //var url:String = "http://pro-us.sbt-corp.com/aspx/member/LaunchGame.aspx"; var request:URLRequest = new URLRequest(url); //var variables:URLVariables = new URLVariables("gameNum=17&as=as1&t=demo&package=a&btnQuit=0"); if(variableString != null && variableString != ""){ var variables:URLVariables = new URLVariables(variableString); variables.exampleSessionId = new Date().getTime(); variables.exampleUserLabel = "guest"; request.data = variables; } webPage = HTMLLoader.createRootWindow(true, null, true, null); webPage.height = systemManager.stage.nativeWindow.height - 66; webPage.width = systemManager.stage.nativeWindow.width; webPage.load(request); webPage.navigateInSystemBrowser = false; flexBrowser.addChild(webPage); } ]]> </mx:Script> <mx:HTML id="flexBrowser" width="1366" height="658" backgroundAlpha="0.45" creationComplete="registerEvents();" x="0" y="0"> </mx:HTML>

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• What is the difference between declaring data attributes inside or outside __init__

  - by user1898540

  I'm trying to get my head around OOP in Python and I'm a bit confused when it comes to declare variables within a class. Should I declare them inside of the __init__ procedure or outside it? What's the difference? The following code works just fine: # Declaring variables within __init__ class MyClass: def __init__(self): country = "" city = "" def information(self): print "Hi! I'm from %s, (%s)"%(self.city,self.country) me = MyClass() me.country = "Spain" me.city = "Barcelona" me.information() But declaring the variables outside of the __init procedure also works: # Declaring variables outside of __init__ class MyClass: country = "" city = "" def information(self): print "Hi! I'm from %s, (%s)"%(self.city,self.country) me = MyClass() me.country = "Spain" me.city = "Barcelona" me.information()

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• What are the rules about using an underscore in a C++ identifier?

  - by Roger Lipscombe

  It's common in C++ to name member variables with some kind of prefix to denote the fact that they're member variables, rather than local variables or parameters. If you've come from an MFC background, you'll probably use "m_foo". I've also seen "myFoo" occasionally. C# (or possibly just .NET) seems to recommend using just an underscore, as in "_foo". Is this allowed by the C++ standard?

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• I can't set main Class variable in onCreate Method

  - by natrollus

  Main class has two variables that want to reach another class: public class MyClassA extends Activity { int i = 1; Button b1; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); this.i = 31; this.b1 = (Button) findViewById(R.id.btn1); ~~ } } Second class want to call variables in mainClass object: public class MyclassB implements OnClickListener{ MyClassA mainClass = new MyClassA(); Button btn = mainClass.b1; int n = mainClass.i; public void OnClick(View arg0){ Log.v("btn:",btn); Log.v("int:",n); } //btn returns null; //int returns 1; But onCreate method not set variables.. Why not set main class variables like this.i=31 ?

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• How to retrieve data from a dialog box?

  - by Ralph

  Just trying to figure out an easy way to either pass or share some data between the main window and a dialog box. I've got a collection of variables in my main window that I want to pass to a dialog box so that they can be edited. They way I've done it now, is I pass in the list to the constructor of the dialog box: private void Button_Click(object sender, RoutedEventArgs e) { var window = new VariablesWindow(_templateVariables); window.Owner = this; window.ShowDialog(); if(window.DialogResult == true) _templateVariables = new List<Variable>(window.Variables); } And then in there, I guess I need to deep-copy the list, public partial class VariablesWindow : Window { public ObservableCollection<Variable> Variables { get; set; } public VariablesWindow(IEnumerable<Variable> vars) { Variables = new ObservableCollection<Variable>(vars); // ... So that when they're edited, it doesn't get reflected back in the main window until the user actually hits "Save". Is that the correct approach? If so, is there an easy way to deep-copy an ObservableCollection? Because as it stands now, I think my Variables are being modified because it's only doing a shallow-copy.

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• C++ header files and variable scope

  - by MrDatabase

  I want to organize my c++ variables and functions in the following way: function prototypes in a header file "stuff.h", function implementation in "stuff.cpp", then say #include "stuff.h" in main.cpp (so I can call functions implemented in stuff.cpp). So far so good. Now I want to declare some variables in stuff.cpp that have global scope (so I can modify the variables in functions implemented in stuff.cpp and main.cpp). This doesn't seem to work. How can I do this?

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• Is there an equivalent to C++'s "friend class" in Java?

  - by Ricket

  In C++ there is a concept of a "friend", which has access to a class's private variables and functions. So if you have: class Foo { friend class Bar; private: int x; } then any instance of the class Bar can modify any Foo instance's x member, despite it being private, because Bar is a friend of Foo. Now I have a situation in Java where this functionality would come in handy. There are three classes: Database, Modifier, Viewer. The Database is just a collection of variables (like a struct). Modifier should be "friends" with Database; that is, it should be able to read and write its variables directly. But Viewer should only be able to read Database's variables. How is this best implemented? Is there a good way to enforce Viewer's read-only access of Database?

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• How can I evaluate variable to another variable before assigning?

  - by HH

  #!/usr/bin/python # # Description: trying to evaluate array -value to variable before assignment # but it overwrites the variable # # How can I evaluate before assigning on the line 16? #Initialization, dummy code? x=0 y=0 variables = [x, y] data = ['2,3,4', '5,5,6'] # variables[0] should be evaluted to `x` here, i.e. x = data[0], how? variables[0] = data[0] if ( variables[0] != x ): print("It does not work, why?"); else: print("It works!");

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• How to create an formatted localized string?

  - by mystify

  I have an localized string which needs to take a few variables. However, in localization it is important that the order of the variables can change from language to language. So this is not a good idea: NSString *text = NSLocalizedString(@"My birthday is at %@ %@ in %@", nil); In some languages some words come before others, while in others it's reverse. I lack of an good example for the moment. How would I provide NAMED variables in an formatted string? Is there any way to do it without some heavy self-made string replacements? Even some numbered variables like {%@1}, {%@2}, and so on would be sufficient... is there a solution?

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• Pass the current state of a function into another function in C/C++

  - by sand

  Is there a way to pass the current state of a function into another function in C/C++? I mean all the parameters and local variables by current state. For example: void funcA (int a, int b) { char c; int d, e; // Do something with the variables. // ... funcB(); // Do something more. } void funcB() { // funcB() should be able to access variables a,b,c,d & e // and any change in these variables reflect into funcA(). } The code is in bad shape if there is a need for funcB() kind of functions. But can it be achieved? This can help if someone is starting to re-factor a long method with multiple parameters.

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• ActionScript Binding Array Objects?

  - by TheDarkIn1978

  i would like to update the numbers i've added to an array from variables, when those variables change. is it possible change these variables and have the array update automatically? var first:Number = 1; var second:Number = 2; var myArray:Array = new Array(first, second); first = 3; second = 4; trace(myArray) //outputs 1,2

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• ActionScript Binding Array Data?

  - by TheDarkIn1978

  i would like to update the numbers i've added to an array from variables, when those variables change. is it possible change these variables and have the array update automatically? var first:Number = 1; var second:Number = 2; var myArray:Array = new Array(first, second); first = 3; second = 4; trace(myArray) //outputs 1,2

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• What data (if any) persists across web-requests in Ruby on Rails?

  - by Daniel Beardsley

  I decided to use the singleton design pattern while creating a view helper class. This got me thinking; will the singleton instance survive across requests? This led to another question, Which variables (if any) survive across web requests and does that change depending on deployment? (Fastcgi, Mongrel, Passenger, ...) I know that Controller instance variables aren't persisted. I know Constants are persisted (or reloaded?). But I don't know about class variables, instance variables on a class, Eigenclasses, ...

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• Reference Data Management

  - by rahulkamath

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} table.MsoTableColorfulListAccent2 {mso-style-name:"Colorful List - Accent 2"; mso-tstyle-rowband-size:1; mso-tstyle-colband-size:1; mso-style-priority:72; mso-style-unhide:no; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-tstyle-shading:#F8EDED; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themetint:25; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; color:black; mso-themecolor:text1;} table.MsoTableColorfulListAccent2FirstRow {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:first-row; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:#9E3A38; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themeshade:204; mso-tstyle-border-bottom:1.5pt solid white; mso-tstyle-border-bottom-themecolor:background1; color:white; mso-themecolor:background1; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2LastRow {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:last-row; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:white; mso-tstyle-shading-themecolor:background1; mso-tstyle-border-top:1.5pt solid black; mso-tstyle-border-top-themecolor:text1; color:#9E3A38; mso-themecolor:accent2; mso-themeshade:204; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2FirstCol {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:first-column; mso-style-priority:72; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2LastCol {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:last-column; mso-style-priority:72; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2OddColumn {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:odd-column; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:#EFD3D2; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themetint:63; mso-tstyle-border-top:cell-none; mso-tstyle-border-left:cell-none; mso-tstyle-border-bottom:cell-none; mso-tstyle-border-right:cell-none; mso-tstyle-border-insideh:cell-none; mso-tstyle-border-insidev:cell-none;} table.MsoTableColorfulListAccent2OddRow {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:odd-row; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:#F2DBDB; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themetint:51;} Reference Data Management Oracle Data Relationship Management (DRM) has always been extremely powerful as an Enterprise MDM solution that can help manage changes to master data in a way that influences enterprise structure, whether it be mastering chart of accounts to enable financial transformation, or revamping organization structures to drive business transformation and operational efficiencies, or mastering sales territories in light of rapid fire acquisitions that require frequent sales territory refinement, equitable distribution of leads and accounts to salespersons, and alignment of budget/forecast with results to optimize sales coverage. Increasingly, DRM is also being utilized by Oracle customers for reference data management, an emerging solution space that deserves some explanation. What is reference data? Reference data is a close cousin of master data. While master data may be more rapidly changing, requires consensus building across stakeholders and lends structure to business transactions, reference data is simpler, more slowly changing, but has semantic content that is used to categorize or group other information assets – including master data – and give them contextual value. The following table contains an illustrative list of examples of reference data by type. Reference data types may include types and codes, business taxonomies, complex relationships & cross-domain mappings or standards. Types & Codes Taxonomies Relationships / Mappings Standards Transaction Codes Industry Classification Categories and Codes, e.g., North America Industry Classification System (NAICS) Product / Segment; Product / Geo Calendars (e.g., Gregorian, Fiscal, Manufacturing, Retail, ISO8601) Lookup Tables (e.g., Gender, Marital Status, etc.) Product Categories City à State à Postal Codes Currency Codes (e.g., ISO) Status Codes Sales Territories (e.g., Geo, Industry Verticals, Named Accounts, Federal/State/Local/Defense) Customer / Market Segment; Business Unit / Channel Country Codes (e.g., ISO 3166, UN) Role Codes Market Segments Country Codes / Currency Codes / Financial Accounts Date/Time, Time Zones (e.g., ISO 8601) Domain Values Universal Standard Products and Services Classification (UNSPSC), eCl@ss International Classification of Diseases (ICD) e.g., ICD9 à IC10 mappings Tax Rates Why manage reference data? Reference data carries contextual value and meaning and therefore its use can drive business logic that helps execute a business process, create a desired application behavior or provide meaningful segmentation to analyze transaction data. Further, mapping reference data often requires human judgment. Sample Use Cases of Reference Data Management Healthcare: Diagnostic Codes The reference data challenges in the healthcare industry offer a case in point. Part of being HIPAA compliant requires medical practitioners to transition diagnosis codes from ICD-9 to ICD-10, a medical coding scheme used to classify diseases, signs and symptoms, causes, etc. The transition to ICD-10 has a significant impact on business processes, procedures, contracts, and IT systems. Since both code sets ICD-9 and ICD-10 offer diagnosis codes of very different levels of granularity, human judgment is required to map ICD-9 codes to ICD-10. The process requires collaboration and consensus building among stakeholders much in the same way as does master data management. Moreover, to build reports to understand utilization, frequency and quality of diagnoses, medical practitioners may need to “cross-walk” mappings -- either forward to ICD-10 or backwards to ICD-9 depending upon the reporting time horizon. Spend Management: Product, Service & Supplier Codes Similarly, as an enterprise looks to rationalize suppliers and leverage their spend, conforming supplier codes, as well as product and service codes requires supporting multiple classification schemes that may include industry standards (e.g., UNSPSC, eCl@ss) or enterprise taxonomies. Aberdeen Group estimates that 90% of companies rely on spreadsheets and manual reviews to aggregate, classify and analyze spend data, and that data management activities account for 12-15% of the sourcing cycle and consume 30-50% of a commodity manager’s time. Creating a common map across the extended enterprise to rationalize codes across procurement, accounts payable, general ledger, credit card, procurement card (P-card) as well as ACH and bank systems can cut sourcing costs, improve compliance, lower inventory stock, and free up talent to focus on value added tasks. Specialty Finance: Point of Sales Transaction Codes and Product Codes In the specialty finance industry, enterprises are confronted with usury laws – governed at the state and local level – that regulate financial product innovation as it relates to consumer loans, check cashing and pawn lending. To comply, it is important to demonstrate that transactions booked at the point of sale are posted against valid product codes that were on offer at the time of booking the sale. Since new products are being released at a steady stream, it is important to ensure timely and accurate mapping of point-of-sale transaction codes with the appropriate product and GL codes to comply with the changing regulations. Multi-National Companies: Industry Classification Schemes As companies grow and expand across geographies, a typical challenge they encounter with reference data represents reconciling various versions of industry classification schemes in use across nations. While the United States, Mexico and Canada conform to the North American Industry Classification System (NAICS) standard, European Union countries choose different variants of the NACE industry classification scheme. Multi-national companies must manage the individual national NACE schemes and reconcile the differences across countries. Enterprises must invest in a reference data change management application to address the challenge of distributing reference data changes to downstream applications and assess which applications were impacted by a given change.

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• How to avoid throwing vexing exceptions?

  - by Mike

  Reading Eric Lippert's article on exceptions was definitely an eye opener on how I should approach exceptions, both as the producer and as the consumer. However, I'm still struggling to define a guideline regarding how to avoid throwing vexing exceptions. Specifically: Suppose you have a Save method that can fail because a) Somebody else modified the record before you, or b) The value you're trying to create already exists. These conditions are to be expected and not exceptional, so instead of throwing an exception you decide to create a Try version of your method, TrySave, which returns a boolean indicating if the save succeeded. But if it fails, how will the consumer know what was the problem? Or would it be best to return an enum indicating the result, kind of Ok/RecordAlreadyModified/ValueAlreadyExists? With integer.TryParse this problem doesn't exist, since there's only one reason the method can fail. Is the previous example really a vexing situation? Or would throwing an exception in this case be the preferred way? I know that's how it's done in most libraries and frameworks, including the Entity framework. How do you decide when to create a Try version of your method vs. providing some way to test beforehand if the method will work or not? I'm currently following these guidelines: If there is the chance of a race condition, then create a Try version. This prevents the need for the consumer to catch an exogenous exception. For example, in the Save method described before. If the method to test the condition pretty much would do all that the original method does, then create a Try version. For example, integer.TryParse(). In any other case, create a method to test the condition.

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• My new favourite traceflag

  - by Dave Ballantyne

  As we are all aware, there are a number of traceflags.  Some documented, some semi-documented and some completely undocumented.  Here is one that is undocumented that Paul White(b|t) mentioned almost as an aside in one of his excellent blog posts. Much has been written about residual predicates and how a predicate can be pushed into a seek/scan operation.  This is a good thing to happen,  it does save a lot of processing from having to be done.  For the uninitiated though: If we have a simple SELECT statement such as : the process that SQL Server goes through to resolve this is : The index IX_Person_LastName_FirstName_MiddleName is navigated to find the first “Smith” For each “Smith” the middle name is checked for being a null. Two operations!, and the execution plan doesnt fully represent all the work that is being undertaken. As you can see there is only a single seek operation, the work undertaken to resolve the condition “MiddleName is not null” has been pushed into it.  This can be seen in the properties. “Seek predicate” is how the index has been navigated, and “Predicate” is the condition run over every row,  a scan inside a seek!. So the question is:  How many rows have been resolved by the seek and how many by the scan ?  How many rows did the filter remove ? Wouldn’t it be nice if this operation could be split ?  That exactly what traceflag 9130 does. Executing the query: That changes the plan rather dramatically, and should be changing how we think about the index seek itself.  The Filter operator has been added and, unsurprisingly, the condition in this is “MiddleName is not null” So it is now evident that the seek operation found 103 Smiths and 60 of those Smiths had a non-null MiddleName. This traceflag has no place on a production system,  dont even think about it

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• Context switches much slower in new linux kernels

  - by Michael Goldshteyn

  We are looking to upgrade the OS on our servers from Ubuntu 10.04 LTS to Ubuntu 12.04 LTS. Unfortunately, it seems that the latency to run a thread that has become runnable has significantly increased from the 2.6 kernel to the 3.2 kernel. In fact the latency numbers we are getting are hard to believe. Let me be more specific about the test. We have a program that has two threads. The first thread gets the current time (in ticks using RDTSC) and then signals a condition variable once a second. The second thread waits on the condition variable and wakes up when it is signaled. It then gets the current time (in ticks using RDTSC). The difference between the time in the second thread and the time in the first thread is computed and displayed on the console. After this the second thread waits on the condition variable once more. So, we get a thread to thread signaling latency measurement once a second as a result. In linux 2.6.32, this latency is somewhere on the order of 2.8-3.5 us, which is reasonable. In linux 3.2.0, this latency is somewhere on the order of 40-100 us. I have excluded any differences in hardware between the two host hosts. They run on identical hardware (dual socket X5687 {Westmere-EP} processors running at 3.6 GHz with hyperthreading, speedstep and all C states turned off). We are changing the affinity to run both threads on physical cores of the same socket (i.e., the first thread is run on Core 0 and the second thread is run on Core 1), so there is no bouncing of threads on cores or bouncing/communication between sockets. The only difference between the two hosts is that one is running Ubuntu 10.04 LTS with kernel 2.6.32-28 (the fast context switch box) and the other is running the latest Ubuntu 12.04 LTS with kernel 3.2.0-23 (the slow context switch box). Have there been any changes in the kernel that could account for this ridiculous slow down in how long it takes for a thread to be scheduled to run?

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• Why does the Ternary\Conditional operator seem significantly faster

  - by Jodrell

  Following on from this question, which I have partially answered. I compile this console app in x64 Release Mode, with optimizations on, and run it from the command line without a debugger attached. using System; using System.Diagnostics; class Program { static void Main() { var stopwatch = new Stopwatch(); var ternary = Looper(10, Ternary); var normal = Looper(10, Normal); if (ternary != normal) { throw new Exception(); } stopwatch.Start(); ternary = Looper(10000000, Ternary); stopWatch.Stop(); Console.WriteLine( "Ternary took {0}ms", stopwatch.ElapsedMilliseconds); stopwatch.Start(); normal = Looper(10000000, Normal); stopWatch.Stop(); Console.WriteLine( "Normal took {0}ms", stopwatch.ElapsedMilliseconds); if (ternary != normal) { throw new Exception(); } Console.ReadKey(); } static int Looper(int iterations, Func<bool, int, int> operation) { var result = 0; for (int i = 0; i < iterations; i++) { var condition = result % 11 == 4; var value = ((i * 11) / 3) % 5; result = operation(condition, value); } return result; } static int Ternary(bool condition, in value) { return value + (condition ? 2 : 1); } static int Normal(int iterations) { if (condition) { return = 2 + value; } return = 1 + value; } } I don't get any exceptions and the output to the console is somthing close to, Ternary took 107ms Normal took 230ms When I break down the CIL for the two logical functions I get this, ... Ternary ... { : ldarg.1 // push second arg : ldarg.0 // push first arg : brtrue.s T // if first arg is true jump to T : ldc.i4.1 // push int32(1) : br.s F // jump to F T: ldc.i4.2 // push int32(2) F: add // add either 1 or 2 to second arg : ret // return result } ... Normal ... { : ldarg.0 // push first arg : brfalse.s F // if first arg is false jump to F : ldc.i4.2 // push int32(2) : ldarg.1 // push second arg : add // add second arg to 2 : ret // return result F: ldc.i4.1 // push int32(1) : ldarg.1 // push second arg : add // add second arg to 1 : ret // return result } Whilst the Ternary CIL is a little shorter, it seems to me that the execution path through the CIL for either function takes 3 loads and 1 or 2 jumps and a return. Why does the Ternary function appear to be twice as fast. I underdtand that, in practice, they are both very quick and indeed, quich enough but, I would like to understand the discrepancy.

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• EJB / JSF java.lang.ClassNotFoundException: com.ericsantanna.jobFC.dao.DAOFactoryRemote from [Module "com.sun.jsf-impl:main" from local module loader

  - by Eric Sant'Anna

  I'm in my first time using EJB and JSF, and I can't resolve this: 20:23:12,457 Grave [javax.enterprise.resource.webcontainer.jsf.application] (http-localhost-127.0.0.1-8081-2) com.ericsantanna.jobFC.dao.DAOFactoryRemote from [Module "com.sun.jsf-impl:main" from local module loader @439db2b2 (roots: C:\jboss-as-7.1.1.Final\modules)]: java.lang.ClassNotFoundException: com.ericsantanna.jobFC.dao.DAOFactoryRemote from [Module "com.sun.jsf-impl:main" from local module loader @439db2b2 (roots: C:\jboss-as-7.1.1.Final\modules)] I'm getting this when I do an action like a selectOneMenu or a commandButton click. DAOFactory.class @Singleton @Remote(DAOFactoryRemote.class) public class DAOFactory implements DAOFactoryRemote { private static final long serialVersionUID = 6030538139815885895L; @PersistenceContext private EntityManager entityManager; @EJB private JobDAORemote jobDAORemote; /** * Default constructor. */ public DAOFactory() { // TODO Auto-generated constructor stub } @Override public JobDAORemote getJobDAO() { JobDAO jobDAO = (JobDAO) jobDAORemote; jobDAO.setEntityManager(entityManager); return jobDAO; } JobDAO.class @Stateless @Remote(JobDAORemote.class) public class JobDAO implements JobDAORemote { private static final long serialVersionUID = -5483992924812255349L; private EntityManager entityManager; /** * Default constructor. */ public JobDAO() { // TODO Auto-generated constructor stub } @Override public void insert(Job t) { entityManager.persist(t); } @Override public Job findById(Class<Job> classe, Long id) { return entityManager.getReference(classe, id); } @Override public Job findByName(Class<Job> clazz, String name) { return entityManager .createQuery("SELECT job FROM " + clazz.getName() + " job WHERE job.nome = :nome" , Job.class) .setParameter("name", name) .getSingleResult(); } ... TriggerFormBean.class @ManagedBean @ViewScoped @Stateless public class TriggerFormBean implements Serializable { private static final long serialVersionUID = -3293560384606586480L; @EJB private DAOFactoryRemote daoFactory; @EJB private TriggerManagerRemote triggerManagerRemote; ... triggerForm.xhtml (a portion with problem) </p:layoutUnit> <p:layoutUnit id="eastConditionPanel" position="center" size="50%"> <p:panel header="Conditions to Release" style="width:97%;height:97%;"> <h:panelGrid columns="2" cellpadding="3"> <h:outputLabel value="Condition Name:" for="conditionName" /> <p:inputText id="conditionName" value="#{triggerFormBean.newCondition.name}" /> </h:panelGrid> <p:commandButton value="Add Condition" update="conditionsToReleaseList" id="addConditionToRelease" actionListener="#{triggerFormBean.addNewCondition}" /> <p:orderList id="conditionsToReleaseList" value="#{triggerFormBean.trigger.conditionsToRelease}" var="condition" controlsLocation="none" itemLabel="#{condition.name}" itemValue="#{condition}" iconOnly="true" style="width:97%;heigth:97%;"/> </p:panel> </p:layoutUnit> In TriggerFormBean.class if comments daoFactory we get the same exception with triggerManagerRemote, both annotated with @EJB. I'm don't understand the relationship between my DAOFactory and the "Module com.sun.jsf-impl:main"... Thanks.

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• Good abbreviations for XML ... things

  - by Peter Turner

  I've never been very good at maintaining a coherent bunch of variable names for interfacing with XML files because I never name the variables in my interfaces the same way across my source. There are Elements, Attributes, Documents, NodeLists, Nodes, DocumentFragments and other stuff. What's a good scheme for keeping track of this stuff as variables? Is there a standard in regard to Hungarian notation? Do you even put anything signifying that the data is actually XML, is this bad practice?

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