explanation - Page 85 - Developer IT

Why does jquery leak memory so badly?

- by Thomas Lane

This is kind of a follow-up to a question I posted last week: http://stackoverflow.com/questions/2429056/simple-jquery-ajax-call-leaks-memory-in-ie I love the jquery syntax and all of its nice features, but I've been having trouble with a page that automatically updates table cells via ajax calls leaking memory. So I created two simple test pages for experimenting. Both pages do an ajax call every .1 seconds. After each successful ajax call, a counter is incremented and the DOM is updated. The script stops after 1000 cycles. One uses jquery for both the ajax call and to update the DOM. The other uses the Yahoo API for the ajax and does a document.getElementById(...).innerHTML to update the DOM. The jquery version leaks memory badly. Running in drip (on XP Home with IE7), it starts at 9MB and finishes at about 48MB, with memory growing linearly the whole time. If I comment out the line that updates the DOM, it still finishes at 32MB, suggesting that even simple DOM updates leak a significant amount of memory. The non-jquery version starts and finishes at about 9MB, regardless of whether it updates the DOM. Does anyone have a good explanation of what is causing jquery to leak so badly? Am I missing something obvious? Is there a circular reference that I'm not aware of? Or does jquery just have some serious memory issues? Here is the source for the leaky (jquery) version: <html> <head> <script type="text/javascript" src="http://www.google.com/jsapi"></script> <script type="text/javascript"> google.load('jquery', '1.4.2'); </script> <script type="text/javascript"> var counter = 0; leakTest(); function leakTest() { $.ajax({ url: '/html/delme.x', type: 'GET', success: incrementCounter }); } function incrementCounter(data) { if (counter<1000) { counter++; $('#counter').text(counter); setTimeout(leakTest,100); } else $('#counter').text('finished.'); } </script> </head> <body> <div>Why is memory usage going up?</div> <div id="counter"></div> </body> </html> And here is the non-leaky version: <html> <head> <script type="text/javascript" src="http://yui.yahooapis.com/2.8.0r4/build/yahoo/yahoo-min.js"></script> <script type="text/javascript" src="http://yui.yahooapis.com/2.8.0r4/build/event/event-min.js"></script> <script type="text/javascript" src="http://yui.yahooapis.com/2.8.0r4/build/connection/connection_core-min.js"></script> <script type="text/javascript"> var counter = 0; leakTest(); function leakTest() { YAHOO.util.Connect.asyncRequest('GET', '/html/delme.x', {success:incrementCounter}); } function incrementCounter(o) { if (counter<1000) { counter++; document.getElementById('counter').innerHTML = counter; setTimeout(leakTest,100); } else document.getElementById('counter').innerHTML = 'finished.' } </script> </head> <body> <div>Memory usage is stable, right?</div> <div id="counter"></div> </body> </html>

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Am I suffering "divitis"? (CSS especialist needed)

- by janoChen

I've read lots of articles that condemn the excessive use of divs. I have a feeling that I might be doing that in the following mark up: HTML: <div id="header"> <div class="container"> <div id="banner"> <h1><a href="http://widerdesign.co.nr/">wider design</a></h1> <ul id="lang"> <li><a href="index.php">English</a></li> <li><a href="es/index.php">Español</a></li> <li><a href="tw/index.php">??(??)</a></li> <li><a href="cn/index.php">??(??)</a></li> </ul> </div> <div id="intro"> <div id="tagline"> <h2>Nulla vitae tortor mauris</h2> <p>Pellentesque faucibus est eu tellus varius in susc...</p> </div> <div id="about"> <h2>right</h2> <p>Pellentesque faucibus est eu tellus varius in susc...</p> </div> </div> </div> </div> CSS: .container { margin: 0 auto; overflow: hidden; width: 960px; } /* header */ #header { background: #EEE; } #header h1 { float: left; } #header h2, #header a, #header p { color: #999; } #header h1 a { background: url(../images/logo.png) no-repeat scroll 0 0; float: left; height: 30px; text-indent: -9999px; width: 500px; } #banner { border-bottom: 1px solid #DDD; padding: 0 0 15px 0; margin: 30px 0 30px 0; overflow: hidden; width: 960px; } #lang { float: right; padding: 9px 0 0 0; } #lang li { float: left; margin: 0 0 0 20px; } #lang li a { font-size: 10px; } /* intro */ #intro { overflow: hidden; padding: 0 0 30px 0; } #tagline { float: left; margin: 0 40px 0 0; width: 540px; /* 560 */ } #tagline h2 { font-size: 24px; } #about { float: right; width: 380px; } Explanation of the use of those divs: header: Defines the background color which expands until the end of the window (lies outside of the div .container). container: centers the content (but not the background). banner: to define the background or border color around ul#lang and h1. intro: same as above but for #tagline and #about (otherwise I have to define say padding or margin for tagline and about individually). Am I overusing divs? Can this be simplified?

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Help with specific Regex: need to match multiple instances of multiple formats in a single string.

- by KevenK

I apologize for the terrible title...it can be hard to try to summarize an entire situation into a single sentence. Let me start by saying that I'm asking because I'm just not a Regex expert. I've used it a bit here and there, but I just come up short with the correct way to meet the following requirements. The Regex that I'm attempting to write is for use in an XML schema for input validation, and used elsewhere in Javascript for the same purpose. There are two different possible formats that are supported. There is a literal string, which must be surrounded by quotation marks, and a Hex-value string which must be surrounded by braces. Some test cases: "this is a literal string" <-- Valid string, enclosed properly in "s "this should " still be correct" <-- Valid string, "s are allowed within (if possible, this requirement could be forgiven if necessary) "{00 11 22}" <-- Valid string, {}'s allow in strings. Another one that can be forgiven if necessary I am bad output <-- Invalid string, no "s "Some more problemss"you know <-- Invalid string, must be fully contained in "s {0A 68 4F 89 AC D2} <-- Valid string, hex characters enclosed in {}s {DDFF1234} <-- Valid string, spaces are ignored for Hex strings DEADBEEF <-- Invalid string, must be contained in either "s or {}s {0A 12 ZZ} <-- Invalid string, 'Z' is not a valid Hex character To satisfy these general requirements, I had come up with the following Regex that seems to work well enough. I'm still fairly new to Regex, so there could be a huge hole here that I'm missing.: ".+"|\{([0-9]|[a-f]|[A-F]| )+\} If I recall correctly, the XML Schema regex automatically assumes beginning and end of line (^ and $ respectively). So, essentially, this regex accepts any string that starts and ends with a ", or starts and ends with {}s and contains only valid Hexidecimal characters. This has worked well for me so far except that I had forgotten about another (although less common, and thus forgotten) input option that completely breaks my regex. Where I made my mistake: Valid input should also allow a user to separate valid strings (of either type, literal/hex) by a comma. This means that a single string should be able to contain more than one of the above valid strings, separated by commas. Luckily, however, a comma is not a supported character within a literal string (although I see that my existing regex does not care about commas). Example test cases: "some string",{0A F1} <-- Valid {1122},{face},"peanut butter" <-- Valid {0D 0A FF FE},"string",{FF FFAC19 85} <-- Valid (Spaces don't matter in Hex values) "Validation is allowed to break, if a comma is found not separating values",{0d 0a} <-- Invalid, comma is a delimiter, but "Validation is allowed to break" and "if a comma..." are not marked as separate strings with "s hi mom,"hello" <-- Invalid, String1 was not enclosed properly in "s or {}s My thoughts are that it is possible to use commas as a delimiter to check each "section" of the string to match a regex similar to the original, but I just am not that advanced in regex yet to come up with a solution on my own. Any help would be appreciated, but ultimately a final solution with an explanation would just stellar. Thanks for reading this huge wall of text!

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What does the `forall` keyword in Haskell/GHC do?

- by JUST MY correct OPINION

I've been banging my head on this one for (quite literally) years now. I'm beginning to kinda/sorta understand how the foreach keyword is used in so-called "existential types" like this: data ShowBox = forall s. Show s => SB s (This despite the confusingly-worded explanations of it in the fragments found all around the web.) This is only a subset, however, of how foreach is used and I simply cannot wrap my mind around its use in things like this: runST :: forall a. (forall s. ST s a) -> a Or explaining why these are different: foo :: (forall a. a -> a) -> (Char,Bool) bar :: forall a. ((a -> a) -> (Char, Bool)) Or the whole RankNTypes stuff that breaks my brain when "explained" in a way that makes me want to do that Samuel L. Jackson thing from Pulp Fiction. (Don't follow that link if you're easily offended by strong language.) The problem, really, is that I'm a dullard. I can't fathom the chicken scratchings (some call them "formulae") of the elite mathematicians that created this language seeing as my university years are over two decades behind me and I never actually had to put what I learnt into use in practice. I also tend to prefer clear, jargon-free English rather than the kinds of language which are normal in academic environments. Most of the explanations I attempt to read on this (the ones I can find through search engines) have these problems: They're incomplete. They explain one part of the use of this keyword (like "existential types") which makes me feel happy until I read code that uses it in a completely different way (like runST, foo and bar above). They're densely packed with assumptions that I've read the latest in whatever branch of discrete math, category theory or abstract algebra is popular this week. (If I never read the words "consult the paper whatever for details of implementation" again, it will be too soon.) They're written in ways that frequently turn even simple concepts into tortuously twisted and fractured grammar and semantics. (I suspect that the last two items are the biggest problem. I wouldn't know, though, since I'm too much a dullard to comprehend them.) It's been asked why Haskell never really caught on in industry. I suspect, in my own humble, unintelligent way, that my experience in figuring out one stupid little keyword -- a keyword that is increasingly ubiquitous in the libraries being written these days -- are also part of the answer to that question. It's hard for a language to catch on when even its individual keywords cause years-long quests to comprehend. Years-long quests which end in failure. So... On to the actual question. Can anybody completely explain the foreach keyword in clear, plain English (or, if it exists somewhere, point to such a clear explanation which I've missed) that doesn't assume I'm a mathematician steeped in the jargon?

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How to notify client about updated UpdatePanel content on server side

- by csh1981

I have a problem with UpdatePanel.Update() which works initially but then stops. I have tumbled with this problem for some time and some background is needed so please read ahead. I have an ASP.net application in which I have a subpage that display computed information in graphs. Each graph is embedded in an UpdatePanel. The graph is a user control that uses the standard asp:Chart for display. My task is to enable this page with AJAX capabilities so the page is responsive during postbacks. When I access this page from another page, during the initial page rendering, I use a wait dialog for each graph and a pageload event on the client side. In the client event, a hidden button is clicked which a server event handles (the hidden button is inside an UpdatePanel so the postback is asynchronous). Each graph is computed and the UpdatePanels are in turn updated with the Chart content. This is done using UpdatePanel.Update. And it is successful. However, I also have some RadioButtons on the page. These are dynamically created. The purpose of them is to switch graph type --- to show the same data in a different way. Same type of time consuming computation is needed in order to do so. I subscribe on each RadioButton's OnCheckedChanged event and the postback is asynchronous since the radiobuttons are inside an UpdatePanel. In the server event handler I determine the type of graph and use this as an input to the Chart control. I then remove the old Chart control from my Panel and adds new Chart and then I call UpdatePanel.Update(). But with no success. Nothing happens, no errors, nothing. Why is this?? I think this is strange because if I compute every Chart data in the initial rendering instead of using the "Wait dialog"-solution described earlier then I can select graph types successfully and all subsequent AJAX requests work as intended. Also, the same code (computing the chart, removal, and adding the Chart control to Panel and UpdatePanel.Update()) is hit during the initial rendering of the page, and it works only the first time. Here is the method that computes the graph and adds it to the panel and update the UpdatePanel: public void UpdateGraph(GraphType type, GraphMapper mapper) { //Panel is the content of UpdatePanelGraph's Panel.Controls.Clear(); chart = new Chart(type, mapper); //Computation happens inside here panel.Controls.Add(chart); //UpdatePanelGraph is in UpdateMode Conditional and has //ChildrenAsTriggers set to false UpdatePanelGraph.Update(); } I really need a way for these radiobuttons to work, possible using some clientside JavaScript or another way of handling things on the server side. I have thought about using a JavaScript postback call on the UpdatePanel instead of the UpdatePanel.Update(). However, the issue I have here is how to notify the client side when the server side is finished with computing the graph? An plausible explanation of the strange behavior is also much appreciated. Any help appreciated, thanks

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Simple Constructor With Initializer List? - C++

- by Alex

Hi all, below I've included my h file, and my problem is that the compiler is not liking my simple exception class's constructor's with initializer lists. It also is saying that string is undeclared identifier, even though I have #include <string> at the top of the h file. Do you see something I am doing wrong? For further explanation, this is one of my domain classes that I'm integrating into a wxWidgets GUI application on Windows. Thanks! Time.h #pragma once #include <string> #include <iostream> // global constants for use in calculation const int HOURS_TO_MINUTES = 60; const int MINUTES_TO_HOURS = 100; class Time { public: // default Time class constructor // initializes all vars to default values Time(void); // ComputeEndTime computes the new delivery end time // params - none // preconditions - vars will be error-free // postconditions - the correct end time will be returned as an int // returns an int int ComputeEndTime(); // GetStartTime is the getter for var startTime // params - none // returns an int int GetStartTime() { return startTime; } // GetEndTime is the getter for var endTime // params - none // returns an int int GetEndTime() { return endTime; } // GetTimeDiff is the getter for var timeDifference // params - none // returns a double double GetTimeDiff() { return timeDifference; } // SetStartTime is the setter for var startTime // params - an int // returns void void SetStartTime(int s) { startTime = s; } // SetEndTime is the setter for var endTime // params - an int // returns void void SetEndTime(int e) { endTime = e; } // SetTimeDiff is the setter for var timeDifference // params - a double // returns void void SetTimeDiff(double t) { timeDifference = t; } // destructor for Time class ~Time(void); private: int startTime; int endTime; double timeDifference; }; class HourOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type HourOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~HourOutOfRangeException() {} private: string message; }; class MinuteOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type MinuteOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~MinuteOutOfRangeException() {} private: string message; }; class PercentageOutOfRangeException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type PercentageOutOfRangeException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~PercentageOutOfRangeException() {} private: string message; }; class StartEndException { public: // param constructor // initializes message to passed paramater // preconditions - param will be a string // postconditions - message will be initialized // params a string // no return type StartEndException(string pMessage) : message(pMessage) {} // GetMessage is getter for var message // params none // preconditions - none // postconditions - none // returns string string GetMessage() { return message; } // destructor ~StartEndException() {} private: string message; };

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map<string, vector<string>> reassignment of vector value

- by user2950936

I am trying to write a program that takes lines from an input file, sorts the lines into 'signatures' for the purpose of combining all words that are anagrams of each other. I have to use a map, storing the 'signatures' as the keys and storing all words that match those signatures into a vector of strings. Afterwards I must print all words that are anagrams of each other on the same line. Here is what I have so far: #include <iostream> #include <string> #include <algorithm> #include <map> #include <fstream> using namespace std; string signature(const string&); void printMap(const map<string, vector<string>>&); int main(){ string w1,sig1; vector<string> data; map<string, vector<string>> anagrams; map<string, vector<string>>::iterator it; ifstream myfile; myfile.open("words.txt"); while(getline(myfile, w1)) { sig1=signature(w1); anagrams[sig1]=data.push_back(w1); //to my understanding this should always work, } //either by inserting a new element/key or //by pushing back the new word into the vector<string> data //variable at index sig1, being told that the assignment operator //cannot be used in this way with these data types myfile.close(); printMap(anagrams); return 0; } string signature(const string& w) { string sig; sig=sort(w.begin(), w.end()); return sig; } void printMap(const map& m) { for(string s : m) { for(int i=0;i<m->second.size();i++) cout << m->second.at(); cout << endl; } } The first explanation is working, didn't know it was that simple! However now my print function is giving me: prob2.cc: In function âvoid printMap(const std::map<std::basic_string<char>, std::vector<std::basic_string<char> > >&)â: prob2.cc:43:36: error: cannot bind âstd::basic_ostream<char>::__ostream_type {aka std::basic_ostream<char>}â lvalue to âstd::basic_ostream<char>&&â In file included from /opt/centos/devtoolset-1.1/root/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../include/c++/4.7.2/iostream:40:0, Tried many variations and they always complain about binding void printMap(const map<string, vector<string>> &mymap) { for(auto &c : mymap) cout << c.first << endl << c.second << endl; }

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Replace conditional with polymorphism refactoring or similar?

- by Anders Svensson

Hi, I have tried to ask a variant of this question before. I got some helpful answers, but still nothing that felt quite right to me. It seems to me this shouldn't really be that hard a nut to crack, but I'm not able to find an elegant simple solution. (Here's my previous post, but please try to look at the problem stated here as procedural code first so as not to be influenced by the earlier explanation which seemed to lead to very complicated solutions: http://stackoverflow.com/questions/2772858/design-pattern-for-cost-calculator-app ) Basically, the problem is to create a calculator for hours needed for projects that can contain a number of services. In this case "writing" and "analysis". The hours are calculated differently for the different services: writing is calculated by multiplying a "per product" hour rate with the number of products, and the more products are included in the project, the lower the hour rate is, but the total number of hours is accumulated progressively (i.e. for a medium-sized project you take both the small range pricing and then add the medium range pricing up to the number of actual products). Whereas for analysis it's much simpler, it is just a bulk rate for each size range. How would you be able to refactor this into an elegant and preferably simple object-oriented version (please note that I would never write it like this in a purely procedural manner, this is just to show the problem in another way succinctly). I have been thinking in terms of factory, strategy and decorator patterns, but can't get any to work well. (I read Head First Design Patterns a while back, and both the decorator and factory patterns described have some similarities to this problem, but I have trouble seeing them as good solutions as stated there. The decorator example seems very complicated for just adding condiments, but maybe it could work better here, I don't know. And the factory pattern example with the pizza factory...well it just seems to create such a ridiculous explosion of classes, at least in their example. I have found good use for factory patterns before, but I can't see how I could use it here without getting a really complicated set of classes) The main goal would be to only have to change in one place (loose coupling etc) if I were to add a new parameter (say another size, like XSMALL, and/or another service, like "Administration"). Here's the procedural code example: public class Conditional { private int _numberOfManuals; private string _serviceType; private const int SMALL = 2; private const int MEDIUM = 8; public int GetHours() { if (_numberOfManuals <= SMALL) { if (_serviceType == "writing") return 30 * _numberOfManuals; if (_serviceType == "analysis") return 10; } else if (_numberOfManuals <= MEDIUM) { if (_serviceType == "writing") return (SMALL * 30) + (20 * _numberOfManuals - SMALL); if (_serviceType == "analysis") return 20; } else //i.e. LARGE { if (_serviceType == "writing") return (SMALL * 30) + (20 * (MEDIUM - SMALL)) + (10 * _numberOfManuals - MEDIUM); if (_serviceType == "analysis") return 30; } return 0; //Just a default fallback for this contrived example } } All replies are appreciated! I hope someone has a really elegant solution to this problem that I actually thought from the beginning would be really simple... Regards, Anders

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Rogue PropertyChanged notifications from ViewModel

- by user1886323

The following simple program is causing me a Databinding headache. I'm new to this which is why I suspect it has a simple answer. Basically, I have two text boxes bound to the same property myString. I have not set up the ViewModel (simply a class with one property, myString) to provide any notifications to the View for when myString is changed, so even although both text boxes operate a two way binding there should be no way that the text boxes update when myString is changed, am I right? Except... In most circumstances this is true - I use the 'change value' button at the bottom of the window to change the value of myString to whatever the user types into the adjacent text box, and the two text boxes at the top, even although they are bound to myString, do not change. Fine. However, if I edit the text in TextBox1, thus changing the value of myString (although only when the text box loses focus due to the default UpdateSourceTrigger property, see reference), TextBox2 should NOT update as it shouldn't receive any updates that myString has changed. However, as soon as TextBox1 loses focus (say click inside TextBox2) TextBox2 is updated with the new value of myString. My best guess so far is that because the TextBoxes are bound to the same property, something to do with TextBox1 updating myString gives TextBox2 a notification that it has changed. Very confusing as I haven't used INotifyPropertyChanged or anything like that. To clarify, I am not asking how to fix this. I know I could just change the binding mode to a oneway option. I am wondering if anyone can come up with an explanation for this strange behaviour? ViewModel: namespace WpfApplication1 { class ViewModel { public ViewModel() { _myString = "initial message"; } private string _myString; public string myString { get { return _myString; } set { if (_myString != value) { _myString = value; } } } } } View: <Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApplication1" Title="MainWindow" Height="350" Width="525"> <Window.DataContext> <local:ViewModel /> </Window.DataContext> <Grid>  <TextBox Height="23" HorizontalAlignment="Left" Margin="166,70,0,0" Name="textBox1" VerticalAlignment="Top" Width="120" Text="{Binding Path=myString, Mode=TwoWay}" /> <TextBox Height="23" HorizontalAlignment="Left" Margin="166,120,0,0" Name="textBox2" VerticalAlignment="Top" Width="120" Text="{Binding Path=myString, Mode=TwoWay}"/>  <Button Name="changevaluebutton" Content="change value" Click="ButtonUpdateArtist_Click" Margin="12,245,416,43" Width="75" /> <Button Content="Show value" Height="23" HorizontalAlignment="Left" Margin="12,216,0,0" Name="showvaluebutton" VerticalAlignment="Top" Width="75" Click="showvaluebutton_Click" /> <Label Content="" Height="23" HorizontalAlignment="Left" Margin="116,216,0,0" Name="showvaluebox" VerticalAlignment="Top" Width="128" /> <TextBox Height="23" HorizontalAlignment="Left" Margin="116,245,0,0" Name="changevaluebox" VerticalAlignment="Top" Width="128" />  <Label Content="TexBox1" Height="23" HorizontalAlignment="Left" Margin="99,70,0,0" Name="label1" VerticalAlignment="Top" Width="61" /> <Label Content="TexBox2" Height="23" HorizontalAlignment="Left" Margin="99,118,0,0" Name="label2" VerticalAlignment="Top" Width="61" /> </Grid> </Window> Code behind for view: namespace WpfApplication1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { ViewModel viewModel; public MainWindow() { InitializeComponent(); viewModel = (ViewModel)this.DataContext; } private void showvaluebutton_Click(object sender, RoutedEventArgs e) { showvaluebox.Content = viewModel.myString; } private void ButtonUpdateArtist_Click(object sender, RoutedEventArgs e) { viewModel.myString = changevaluebox.Text; } } }

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Problem with large number of markers on the map...

- by bobetko

I am working on an Android app that already exists on iPhone. In the app, there is a Map activity that has (I counted) around 800 markers in four groups marked by drawable in four different colors. Each group can be turned on or off. Information about markers I have inside List. I create a mapOverlay for each group, then I attach that overlay to the map. I strongly believe that coding part I did properly. But I will attach my code anyway... The thing is, my Nexus One can't handle map with all those markers. It takes around 15 seconds just to draw 500 markers. Then when all drawn, map is not quite smooth. It is sort of hard to zoom and navigate around. It can be done, but experience is bad and I would like to see if something can be done there. iPhone seems doesn't have problems showing all these markers. It takes roughly about 1-2 seconds to show all of them and zooming and panning is not that bad. Slow down is noticeable but still acceptable. I personally think it is no good to draw all those markers, but app is designed by somebody else and I am not supposed to make any drastic changes. I am not sure what to do here. It seems I will have to come up with different functionality, maybe use GPS location, if known, and draw only markers within some radius, or, if location not known, use center of the screen(map) and draw markers around that. I will have to have reasonable explanation for my bosses in case I make these changes. I appreciate if anybody has any idas. And the code: ... for (int m = 0; m < ArrList.size(); m++) { tName = ArrList.get(m).get("name").toString(); tId = ArrList.get(m).get("id").toString(); tLat = ArrList.get(m).get("lat").toString();; tLng = ArrList.get(m).get("lng").toString();; try { lat = Double.parseDouble(tLat); lng = Double.parseDouble(tLng); p1 = new GeoPoint( (int) (lat * 1E6), (int) (lng * 1E6)); OverlayItem overlayitem = new OverlayItem(p1, tName, tId); itemizedoverlay.addOverlay(overlayitem); } catch (NumberFormatException e) { Log.d(TAG, "NumberFormatException" + e); } } mapOverlays.add(itemizedoverlay); mapView.postInvalidate(); ................................ public class HelloItemizedOverlay extends ItemizedOverlay<OverlayItem> { private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>(); private Context mContext; public HelloItemizedOverlay(Drawable defaultMarker, Context context) { super(boundCenterBottom(defaultMarker)); mContext = context; } public void addOverlay(OverlayItem overlay) { mOverlays.add(overlay); populate(); } @Override protected OverlayItem createItem(int i) { return mOverlays.get(i); } @Override public int size() { return mOverlays.size(); } @Override protected boolean onTap(int index) { final OverlayItem item = mOverlays.get(index); ... EACH MARKER WILL HAVE ONCLICK EVENT THAT WILL PRODUCE CLICABLE ... BALOON WITH MARKER'S NAME. return true; } }

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What is the best practice when coding math class/functions ?

- by Isaac Clarke

Introductory note : I voluntarily chose a wide subject. You know that quote about learning a cat to fish, that's it. I don't need an answer to my question, I need an explanation and advice. I know you guys are good at this ;) Hi guys, I'm currently implementing some algorithms into an existing program. Long story short, I created a new class, "Adder". An Adder is a member of another class representing the physical object actually doing the calculus , which calls adder.calc() with its parameters (merely a list of objects to do the maths on). To do these maths, I need some parameters, which do not exist outside of the class (but can be set, see below). They're neither config parameters nor members of other classes. These parameters are D1 and D2, distances, and three arrays of fixed size : alpha, beta, delta. I know some of you are more comfortable reading code than reading text so here you go : class Adder { public: Adder(); virtual Adder::~Adder(); void set( float d1, float d2 ); void set( float d1, float d2, int alpha[N_MAX], int beta[N_MAX], int delta[N_MAX] ); // Snipped prototypes float calc( List& ... ); // ... inline float get_d1() { return d1_ ;}; inline float get_d2() { return d2_ ;}; private: float d1_; float d2_; int alpha_[N_MAX]; // A #define N_MAX is done elsewhere int beta_[N_MAX]; int delta_[N_MAX]; }; Since this object is used as a member of another class, it is declared in a *.h : private: Adder adder_; By doing that, I couldn't initialize the arrays (alpha/beta/delta) directly in the constructor ( int T[3] = { 1, 2, 3 }; ), without having to iterate throughout the three arrays. I thought of putting them in static const, but I don't think that's the proper way of solving such problems. My second guess was to use the constructor to initialize the arrays Adder::Adder() { int alpha[N_MAX] = { 0, -60, -120, 180, 120, 60 }; int beta[N_MAX] = { 0, 0, 0, 0, 0, 0 }; int delta[N_MAX] = { 0, 0, 180, 180, 180, 0 }; set( 2.5, 0, alpha, beta, delta ); } void Adder::set( float d1, float d2 ) { if (d1 > 0) d1_ = d1; if (d2 > 0) d2_ = d2; } void Adder::set( float d1, float d2, int alpha[N_MAX], int beta[N_MAX], int delta[N_MAX] ) { set( d1, d2 ); for (int i = 0; i < N_MAX; ++i) { alpha_[i] = alpha[i]; beta_[i] = beta[i]; delta_[i] = delta[i]; } } My question is : Would it be better to use another function - init() - which would initialize arrays ? Or is there a better way of doing that ? My bonus question is : Did you see some mistakes or bad practice along the way ?

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How to search Multiple Sites using Lucene Search engine API?

- by Wael Salman

Hope that someone can help me as soon as possible :-) I would like to know how can we search Multiple Sites using Lucene??! (All sites are in one index). I have succeeded to search one website , and to index multiple sites, however I am not able to search all websites. Consider this method that I have: private void PerformSearch() { DateTime start = DateTime.Now; //Create the Searcher object string strIndexDir = Server.MapPath("index") + @"\" + mstrURL; IndexSearcher objSearcher = new IndexSearcher(strIndexDir); //Parse the query, "text" is the default field to search Query objQuery = QueryParser.Parse(mstrQuery, "text", new StandardAnalyzer()); //Create the result DataTable mobjDTResults.Columns.Add("title", typeof(string)); mobjDTResults.Columns.Add("path", typeof(string)); mobjDTResults.Columns.Add("score", typeof(string)); mobjDTResults.Columns.Add("sample", typeof(string)); mobjDTResults.Columns.Add("explain", typeof(string)); //Perform search and get hit count Hits objHits = objSearcher.Search(objQuery); mintTotal = objHits.Length(); //Create Highlighter QueryHighlightExtractor highlighter = new QueryHighlightExtractor(objQuery, new StandardAnalyzer(), "<B>", "</B>"); //Initialize "Start At" variable mintStartAt = GetStartAt(); //How many items we should show? int intResultsCt = GetSmallerOf(mintTotal, mintMaxResults + mintStartAt); //Loop through results and display for (int intCt = mintStartAt; intCt < intResultsCt; intCt++) { //Get the document from resuls index Document doc = objHits.Doc(intCt); //Get the document's ID and set the cache location string strID = doc.Get("id"); string strLocation = ""; if (mstrURL.Substring(0,3) == "www") strLocation = Server.MapPath("cache") + @"\" + mstrURL + @"\" + strID + ".htm"; else strLocation = doc.Get("path") + doc.Get("filename"); //Load the HTML page from cache string strPlainText; using (StreamReader sr = new StreamReader(strLocation, System.Text.Encoding.Default)) { strPlainText = ParseHTML(sr.ReadToEnd()); } //Add result to results datagrid DataRow row = mobjDTResults.NewRow(); if (mstrURL.Substring(0,3) == "www") row["title"] = doc.Get("title"); else row["title"] = doc.Get("filename"); row["path"] = doc.Get("path"); row["score"] = String.Format("{0:f}", (objHits.Score(intCt) * 100)) + "%"; row["sample"] = highlighter.GetBestFragments(strPlainText, 200, 2, "..."); Explanation objExplain = objSearcher.Explain(objQuery, intCt); row["explain"] = objExplain.ToHtml(); mobjDTResults.Rows.Add(row); } objSearcher.Close(); //Finalize results information mTsDuration = DateTime.Now - start; mintFromItem = mintStartAt + 1; mintToItem = GetSmallerOf(mintStartAt + mintMaxResults, mintTotal); } as you can see that I use the site URL 'mstrURL' when I create the search object string strIndexDir = Server.MapPath("index") + @"\" + mstrURL; How can I do the same when I want to search multiple sites?? Actually I am using the code from http://www.keylimetie.com/blog/2005/8/4/lucenenet/

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How to make MySQL utilize available system resources, or find "the real problem"?

- by anonymous coward

This is a MySQL 5.0.26 server, running on SuSE Enterprise 10. This may be a Serverfault question. The web user interface that uses these particular queries (below) is showing sometimes 30+, even up to 120+ seconds at the worst, to generate the pages involved. On development, when the queries are run alone, they take up to 20 seconds on the first run (with no query cache enabled) but anywhere from 2 to 7 seconds after that - I assume because the tables and indexes involved have been placed into ram. From what I can tell, the longest load times are caused by Read/Update Locking. These are MyISAM tables. So it looks like a long update comes in, followed by a couple 7 second queries, and they're just adding up. And I'm fine with that explanation. What I'm not fine with is that MySQL doesn't appear to be utilizing the hardware it's on, and while the bottleneck seems to be the database, I can't understand why. I would say "throw more hardware at it", but we did and it doesn't appear to have changed the situation. Viewing a 'top' during the slowest times never shows much cpu or memory utilization by mysqld, as if the server is having no trouble at all - but then, why are the queries taking so long? How can I make MySQL use the crap out of this hardware, or find out what I'm doing wrong? Extra Details: On the "Memory Health" tab in the MySQL Administrator (for Windows), the Key Buffer is less than 1/8th used - so all the indexes should be in RAM. I can provide a screen shot of any graphs that might help. So desperate to fix this issue. Suffice it to say, there is legacy code "generating" these queries, and they're pretty much stuck the way they are. I have tried every combination of Indexes on the tables involved, but any suggestions are welcome. Here's the current Create Table statement from development (the 'experimental' key I have added, seems to help a little, for the example query only): CREATE TABLE `registration_task` ( `id` varchar(36) NOT NULL default '', `date_entered` datetime NOT NULL default '0000-00-00 00:00:00', `date_modified` datetime NOT NULL default '0000-00-00 00:00:00', `assigned_user_id` varchar(36) default NULL, `modified_user_id` varchar(36) default NULL, `created_by` varchar(36) default NULL, `name` varchar(80) NOT NULL default '', `status` varchar(255) default NULL, `date_due` date default NULL, `time_due` time default NULL, `date_start` date default NULL, `time_start` time default NULL, `parent_id` varchar(36) NOT NULL default '', `priority` varchar(255) NOT NULL default '9', `description` text, `order_number` int(11) default '1', `task_number` int(11) default NULL, `depends_on_id` varchar(36) default NULL, `milestone_flag` varchar(255) default NULL, `estimated_effort` int(11) default NULL, `actual_effort` int(11) default NULL, `utilization` int(11) default '100', `percent_complete` int(11) default '0', `deleted` tinyint(1) NOT NULL default '0', `wf_task_id` varchar(36) default '0', `reg_field` varchar(8) default '', `date_offset` int(11) default '0', `date_source` varchar(10) default '', `date_completed` date default '0000-00-00', `completed_id` varchar(36) default NULL, `original_name` varchar(80) default NULL, PRIMARY KEY (`id`), KEY `idx_reg_task_p` (`deleted`,`parent_id`), KEY `By_Assignee` (`assigned_user_id`,`deleted`), KEY `status_assignee` (`status`,`deleted`), KEY `experimental` (`deleted`,`status`,`assigned_user_id`,`parent_id`,`date_due`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 And one of the ridiculous queries in question: SELECT users.user_name assigned_user_name, registration.FIELD001 parent_name, registration_task.status status, registration_task.date_modified date_modified, registration_task.date_due date_due, registration.FIELD240 assigned_wf, if(LENGTH(registration_task.description)>0,1,0) has_description, registration_task.* FROM registration_task LEFT JOIN users ON registration_task.assigned_user_id=users.id LEFT JOIN registration ON registration_task.parent_id=registration.id where (registration_task.status != 'Completed' AND registration.FIELD001 LIKE '%' AND registration_task.name LIKE '%' AND registration.FIELD060 LIKE 'GN001472%') AND registration_task.deleted=0 ORDER BY date_due asc LIMIT 0,20; my.cnf - '[mysqld]' section. [mysqld] port = 3306 socket = /var/lib/mysql/mysql.sock skip-locking key_buffer = 384M max_allowed_packet = 100M table_cache = 2048 sort_buffer_size = 2M net_buffer_length = 100M read_buffer_size = 2M read_rnd_buffer_size = 160M myisam_sort_buffer_size = 128M query_cache_size = 16M query_cache_limit = 1M EXPLAIN above query, without additional index: +----+-------------+-------------------+--------+--------------------------------+----------------+---------+------------------------------------------------+---------+-----------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------------------+--------+--------------------------------+----------------+---------+------------------------------------------------+---------+-----------------------------+ | 1 | SIMPLE | registration_task | ref | idx_reg_task_p,status_assignee | idx_reg_task_p | 1 | const | 1067354 | Using where; Using filesort | | 1 | SIMPLE | registration | eq_ref | PRIMARY,gbl | PRIMARY | 8 | sugarcrm401.registration_task.parent_id | 1 | Using where | | 1 | SIMPLE | users | ref | PRIMARY | PRIMARY | 38 | sugarcrm401.registration_task.assigned_user_id | 1 | | +----+-------------+-------------------+--------+--------------------------------+----------------+---------+------------------------------------------------+---------+-----------------------------+ EXPLAIN above query, with 'experimental' index: +----+-------------+-------------------+--------+-----------------------------------------------------------+------------------+---------+------------------------------------------------+--------+-----------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------------------+--------+-----------------------------------------------------------+------------------+---------+------------------------------------------------+--------+-----------------------------+ | 1 | SIMPLE | registration_task | range | idx_reg_task_p,status_assignee,NewIndex1,tcg_experimental | tcg_experimental | 259 | NULL | 103345 | Using where; Using filesort | | 1 | SIMPLE | registration | eq_ref | PRIMARY,gbl | PRIMARY | 8 | sugarcrm401.registration_task.parent_id | 1 | Using where | | 1 | SIMPLE | users | ref | PRIMARY | PRIMARY | 38 | sugarcrm401.registration_task.assigned_user_id | 1 | | +----+-------------+-------------------+--------+-----------------------------------------------------------+------------------+---------+------------------------------------------------+--------+-----------------------------+

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Why isn't the inline element inheriting height from its children?

- by jbarz

I'm trying to make a rather complicated grid of images and information (almost like Pinterest). Specifically, I'm trying to inline position one set of <ul>s right after another. I have it working but one aspect is causing issues so I'm trying to ask about this small piece to avoid the complication of the whole problem. In order to horizontally align the images and their information we are using inline <li>s with other inline-block level elements inside of them. Everything works correctly for the most part except that the <li>s have almost no height. HTML and CSS is in JSFiddle here if you want to mess with it in addition to below: HTML: <div> <ul class="Container"> <li> <span class="Item"> <a href="#"><img src="http://jsfiddle.net/img/logo.png"/></a> <span class="Info"> <a href="#">Title One</a> <span class="Details">One Point One</span> </span> </span> </li> <li> <span class="Item"> <a href="#"><img src="http://jsfiddle.net/img/logo.png"/></a> <span class="Info"> <a href="#">Title Two</a> <span class="Details">Two Point One</span> </span> </span> </li> </ul> CSS: .Container { list-style-type:none; } .Container li { background-color:grey; display:inline; text-align:center; } .Container li .Item { border:solid 2px #ccc; display:inline-block; min-height:50px; vertical-align:top; width:170px; } .Container li .Item .Info { display:inline-block; } .Container li .Item .Info a { display:inline-block; width:160px; } If you check out the result in the jsfiddle link you can see that the grey background only encompasses a small strip of the whole <li>. I know that changing the <li> to display:inline-block solves this problem but that isn't feasible for other reasons. So first of all, I'm just looking to see if anyone understands why the inline <li> element doesn't have any height. I can't find anything in the spec that explains this. I know I can't add height to an inline element but any explanation as to why this is happening that might enable me to fix would be great. Secondly, if you inspect the elements using IE's Developer Mode you will see that although the background color is in the correct location, the actual location of the <li>'s bounding box is at the bottom of the container according to hovering over the element. I could deal with this problem if it was at the top in every browser but it apparently varies. NOTE: I don't really care about older browsers in this case but I don't use HTML5 or JavaScript positioning. Thanks.

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Sending typedef struct containing void* by creating MPI drived datatype.

- by hankol

what I understand studying MPI specification is that an MPI send primitive refer to a memory location (or a send buffer) pointed by the data to be sent and take the data in that location which then passed as a message to the another Process. Though it is true that virtual address of a give process will be meaningless in another process memory address; It is ok to send data pointed by pointer such as void pointer as MPI will any way pass the data itself as a message For example the following works correctly: // Sender Side. int x = 100; void* snd; MPI_Send(snd,4,MPI_BYTE,1,0,MPI_COMM_WORLD); // Receiver Side. void* rcv; MPI_Recv(rcv, 4,MPI_BYTE,0,0,MPI_COMM_WORLD); but when I add void* snd in a struct and try to send the struct this will no succeed. I don't understand why the previous example work correctly but not the following. Here, I have defined a typedef struct and then create an MPI_DataType from it. With the same explanation of the above the following should also have succeed, unfortunately it is not working. here is the code: #include "mpi.h" #include<stdio.h> int main(int args, char *argv[]) { int rank, source =0, tag=1, dest=1; int bloackCount[2]; MPI_Init(&args, &argv); typedef struct { void* data; int tag; } data; data myData; MPI_Datatype structType, oldType[2]; MPI_Status stat; /* MPI_Aint type used to idetify byte displacement of each block (array)*/ MPI_Aint offsets[2], extent; MPI_Comm_rank(MPI_COMM_WORLD, &rank); offsets[0] = 0; oldType[0] = MPI_BYTE; bloackCount[0] = 1; MPI_Type_extent(MPI_INT, &extent); offsets[1] = 4 * extent; /*let say the MPI_BYTE will contain ineteger : size of int * extent */ oldType[1] = MPI_INT; bloackCount[1] = 1; MPI_Type_create_struct(2, bloackCount,offsets,oldType, &structType); MPI_Type_commit(&structType); if(rank == 0){ int x = 100; myData.data = &x; myData.tag = 99; MPI_Send(&myData,1,structType, dest, tag, MPI_COMM_WORLD); } if(rank == 1 ){ MPI_Recv(&myData, 1, structType, source, tag, MPI_COMM_WORLD, &stat); // with out this the following printf() will properly print the value 99 for // myData.tag int x = *(int *) myData.data; printf(" \n Process %d, Received : %d , %d \n\n", rank , myData.tag, x); } MPI_Type_free(&structType); MPI_Finalize(); } Error message running the code: [Looks like I am trying to access an invalid memory address space in the second process] [ubuntu:04123] *** Process received signal *** [ubuntu:04123] Signal: Segmentation fault (11) [ubuntu:04123] Signal code: Address not mapped (1) [ubuntu:04123] Failing at address: 0xbfe008bc [ubuntu:04123] [ 0] [0xb778240c] [ubuntu:04123] [ 1] GenericstructType(main+0x161) [0x8048935] [ubuntu:04123] [ 2] /lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3) [0xb750f4d3] [ubuntu:04123] [ 3] GenericstructType() [0x8048741] [ubuntu:04123] *** End of error message *** Can some please explain to me why it is not working. any advice will also be appreciated thanks,

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my Search method is coming up with all nulls

- by Epic.Distortion

Let me give a quick explanation. I took a 5 week course through a company on Java in July. They covered basic stuff, like console app, crud operations, mysql, and n-tier architecture. Since the course ended I didn't use it much because I went back to work, and other medical reasons surfaced....blah blah. I was told by the company to make a simple program to reflect what I learned. Turns out I retained very little. I decided to make a video game starage program. It would be used to stare your video games so you wouldn't have to search your bookcase(or how ever you store your games.) It is a basic console app using the crud operations with MYSQL. I can't get my search function to actually work. I have 2 layers a Presentation layer and a Logic layer. The search method allows them to search for a game by the title. when i bring run the program and use Search it only displays the title and the rest is null. here is my Presentation layer: private static Games SearchForGame() { Logic aref = new Logic(); Games g = new Games(); Scanner scanline = new Scanner(System.in); System.out.println("Please enter the name of the game you wish to find:"); g.setTitle(scanline.nextLine()); aref.SearchGame(); System.out.println(); System.out.println("Game Id: " + g.getGameId()); System.out.println("Title: " + g.getTitle()); System.out.println("Rating: " + g.getRating()); System.out.println("Platform: "+ g.getPlatform()); System.out.println("Developer: "+ g.getDeveloper()); return g; } and here is my logic layer public Games SearchGame() { Games g = new Games(); try { Class.forName(driver).newInstance(); Connection conn = DriverManager.getConnection(url+dbName,userName,password); java.sql.PreparedStatement statement = conn.prepareStatement("SELECT GameId,Title,Rating,Platform,Developer FROM games WHERE Title=?"); statement.setString(1, g.getTitle()); ResultSet rs = statement.executeQuery(); while(rs.next()){ g.setGameId(rs.getInt("GameId")); g.setTitle(rs.getString("Title")); g.setRating(rs.getString("Rating")); g.setPlatform(rs.getString("Platform")); g.setDeveloper(rs.getString("Developer")); statement.executeUpdate(); } } catch (Exception e) { e.printStackTrace(); } return g; } here is also my last results Please enter the name of the game you wish to find: Skyrim Game Id: 0 Title: Skyrim Rating: null Platform: null Developer: null any help would be greatly appreciated and thanks in advance EDIT: here is my code for my games class public class Games { public int GameId; public String Title; public String Rating; public String Platform; public String Developer; public int getGameId() { return GameId; } public int setGameId(int gameId) { return GameId = gameId; } public String getTitle() { return Title; } public String setTitle(String title) { return Title = title; } public String getRating() { return Rating; } public void setRating(String rating) { Rating = rating; } public String getPlatform() { return Platform; } public void setPlatform(String platform) { Platform = platform; } public String getDeveloper() { return Developer; } public void setDeveloper(String developer) { Developer = developer; } }

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HTML/CSS - No 100% height on div in IE

- by Jordan Rynard

Okay, so I've got a problem - and I'd love to have it fixed. I am using my favourite way of setting up a simple header/content/footer layout. The problem is that any elements I add to the 'content' div of my layout can not be expanded to 100% in Internet Explorer (as far as I know, IE only). I understand there is no height declared to the 'content' element, but because of the style of its positioning (declaring an absolute top AND bottom), the element fills the desired area. (The content element has a background color defined so you can see that the div is in fact filling between both the header and the footer.) So my problem is, since the div is clearly expanded between the two, why can't a child be set to 100% to fill that area? If anyone has any solutions, I'd love to hear them. (I'm looking for a solution that won't involve designing by an entire different layout.. or at least perhaps an explanation of why this is happening. I'm assuming at this point it's because of the lack of a height declaration -- but the div is expanded, so I don't get it!) You can view a page of the example here: http://www.elizabethlouter.com/html/index.html And here is the code as used on the page: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta name="robots" content="noindex" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>No 100% height on 'content' child div in IE</title> </head> <style> html, body { width:100%; height:100%; margin:0px; padding:0px; } body { position:relative; } #wrapper { position:absolute; top:0px; width:960px; height:100%; left:50%; margin-left:-480px; } #header{ position:absolute; top:0px; left:0px; width:100%; height:200px; background-color:#999; } #content{ position:absolute; top:100px; bottom:50px; left:0px; width:100%; background-color:#F7F7F7; } #content_1{ width:200px; background-color:black; height:100%; } #footer{ position:absolute; bottom:0px; left:0px; width:100%; height:50px; background-color:#999; } </style> <body> <div id="wrapper"> <div id="header"> </div> <div id="content"> <div id="content_1"> </div> </div> <div id="footer"> </div> </div> </body> </html>

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Upgrading Team Foundation Server 2008 to 2010

- by Martin Hinshelwood

I am sure you will have seen my posts on upgrading our internal Team Foundation Server from TFS2008 to TFS2010 Beta 2, RC and RTM, but what about a fresh upgrade of TFS2008 to TFS2010 using the RTM version of TFS. One of our clients is taking the plunge with TFS2010, so I have the job of doing the upgrade. It is sometimes very useful to have a team member that starts work when most of the Sydney workers are heading home as I can do the upgrade without impacting them. The down side is that if you have any blockers then you can be pretty sure that everyone that can deal with your problem is asleep I am starting with an existing blank installation of TFS 2010, but Adam Cogan let slip that he was the one that did the install so I thought it prudent to make sure that it was OK. Verifying Team Foundation Server 2010 We need to check that TFS 2010 has been installed correctly. First, check the Admin console and have a root about for any errors. Figure: Even the SQL Setup looks good. I don’t know how Adam did it! Backing up the Team Foundation Server 2008 Databases As we are moving from one server to another (recommended method) we will be taking a backup of our TFS2008 databases and resorting them to the SQL Server for the new TFS2010 Server. Do not just detach and reattach. This will cause problems with the version of the database. If you are running a test migration you just need to create a backup of the TFS 2008 databases, but if you are doing the live migration then you should stop IIS on the TFS 2008 server before you backup the databases. This will stop any inadvertent check-ins or changes to TFS 2008. Figure: Stop IIS before you take a backup to prevent any TFS 2008 changes being written to the database. It is good to leave a little time between taking the TFS 2008 server offline and commencing the upgrade as there is always one developer who has not finished and starts screaming. This time it was John Liu that needed 10 more minutes to make his changes and check-in, so I always give it 30 minutes and see if anyone screams. John Liu [SSW] said: are you doing something to TFS :-O MrHinsh [SSW UK][VS ALM MVP] said: I have stopped TFS 2008 as per my emails John Liu [SSW] said: haven't finish check in @_@ can we have it for 10mins? :) MrHinsh [SSW UK][VS ALM MVP] said: TFS 2008 has been started John Liu [SSW] said: I love you! -IM conversation at TFS Upgrade +25 minutes After John confirmed that he had everything done I turned IIS off again and made a cup of tea. There were no more screams so the upgrade can continue. Figure: Backup all of the databases for TFS and include the Reporting Services, just in case. Figure: Check that all the backups have been taken Once you have your backups, you need to copy them to your new TFS2010 server and restore them. This is a good way to proceed as if we have any problems, or just plain run out of time, then you just turn the TFS 2008 server back on and all you have lost is one upgrade day, and not 10 developer days. As per the rules, you should record the number of files and the total number of areas and iterations before the upgrade so you have something to compare to: TFS2008 File count: Type Count 1 1845 2 15770 Areas & Iterations: 139 You can use this to verify that the upgrade was successful. it should however be noted that the numbers in TFS 2010 will be bigger. This is due to some of the sorting out that TFS does during the upgrade process. Restore Team Foundation Server 2008 Databases Restoring the databases is much more time consuming than just attaching them as you need to do them one at a time. But you may be taking a backup of an operational database and need to restore all your databases to a particular point in time instead of to the latest. I am doing latest unless I encounter any problems. Figure: Restore each of the databases to either a latest or specific point in time. Figure: Restore all of the required databases Now that all of your databases are restored you now need to upgrade them to Team Foundation Server 2010. Upgrade Team Foundation Server 2008 Databases This is probably the easiest part of the process. You need to call a fire and forget command that will go off to the database specified, find the TFS 2008 databases and upgrade them to 2010. During this process all of the 6 main TFS 2008 databases are merged into the TfsVersionControl database, upgraded and then the database is renamed to TFS_[CollectionName]. The rename is only the database and not the physical files, so it is worth going back and renaming the physical file as well. This keeps everything neat and tidy. If you plan to keep the old TFS 2008 server around, for example if you are doing a test migration first, then you will need to change the TFS GUID. This GUID is unique to each TFS instance and is preserved when you upgrade. This GUID is used by the clients and they can get a little confused if there are two servers with the same one. To kick of the upgrade you need to open a command prompt and change the path to “C:\Program Files\Microsoft Team Foundation Server 2010\Tools” and run the “import” command in “tfsconfig”. TfsConfig import /sqlinstance:<Previous TFS Data Tier> /collectionName:<Collection Name> /confirmed Imports a TFS 2005 or 2008 data tier as a new project collection. Important: This command should only be executed after adequate backups have been performed. After you import, you will need to configure portal and reporting settings via the administration console. EXAMPLES -------- TfsConfig import /sqlinstance:tfs2008sql /collectionName:imported /confirmed TfsConfig import /sqlinstance:tfs2008sql\Instance /collectionName:imported /confirmed OPTIONS: -------- sqlinstance The sql instance of the TFS 2005 or 2008 data tier. The TFS databases at that location will be modified directly and will no longer be usable as previous version databases. Ensure you have back-ups. collectionName The name of the new Team Project Collection. confirmed Confirm that you have backed-up databases before importing. This command will automatically look for the TfsIntegration database and verify that all the other required databases exist. In this case it took around 5 minutes to complete the upgrade as the total database size was under 700MB. This was unlike the upgrade of SSW’s production database with over 17GB of data which took a few hours. At the end of the process you should get no errors and no warnings. The Upgrade operation on the ApplicationTier feature has completed. There were 0 errors and 0 warnings. As this is a new server and not a pure upgrade there should not be a problem with the GUID. If you think at any point you will be doing this more than once, for example doing a test migration, or merging many TFS 2008 instances into a single one, then you should go back and rename the physical TfsVersionControl.mdf file to the same as the new collection. This will avoid confusion later down the line. To do this, detach the new collection from the server and rename the physical files. Then reattach and change the physical file locations to match the new name. You can follow http://www.mssqltips.com/tip.asp?tip=1122 for a more detailed explanation of how to do this. Figure: Stop the collection so TFS does not take a wobbly when we detach the database. When you try to start the new collection again you will get a conflict with project names and will require to remove the Test Upgrade collection. This is fine and it just needs detached. Figure: Detaching the test upgrade from the new Team Foundation Server 2010 so we can start the new Collection again. You will now be able to start the new upgraded collection and you are ready for testing. Do you remember the stats we took off the TFS 2008 server? TFS2008 File count: Type Count 1 1845 2 15770 Areas & Iterations: 139 Well, now we need to compare them to the TFS 2010 stats, remembering that there will probably be more files under source control. TFS2010 File count: Type Count 1 19288 Areas & Iterations: 139 Lovely, the number of iterations are the same, and the number of files is bigger. Just what we were looking for. Testing the upgraded Team Foundation Server 2010 Project Collection Can we connect to the new collection and project? Figure: We can connect to the new collection and project. Figure: make sure you can connect to The upgraded projects and that you can see all of the files. Figure: Team Web Access is there and working. Note that for Team Web Access you now use the same port and URL as for TFS 2010. So in this case as I am running on the local box you need to use http://localhost:8080/tfs which will redirect you to http://localhost:8080/tfs/web for the web access. If you need to connect with a Visual Studio 2008 client you will need to use the full path of the new collection, http://[servername]/tfs/[collectionname] and this will work with all of your collections. With Visual Studio 2005 you will only be able to connect to the Default collection and in both VS2008 and VS2005 you will need to install the forward compatibility updates. Visual Studio Team System 2005 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 Visual Studio Team System 2008 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 To make sure that you have everything up to date, make sure that you run SSW Diagnostics and get all green ticks. Upgrade Done! At this point you can send out a notice to everyone that the upgrade is complete and and give them the connection details. You need to remember that at this stage we have 2008 project upgraded to run under TFS 2010 but it is still running under that same process template that it was running before. You can only “enable” 2010 features in a process template you can’t upgrade. So what to do? Well, you need to create a new project and migrate things you want to keep across. Souse code is easy, you can move or Branch, but Work Items are more difficult as you can’t move them between projects. This instance is complicated more as the old project uses the Conchango/EMC Scrum for Team System template and I will need to write a script/application to get the work items across with their attachments in tact. That is my next task! Technorati Tags: TFS 2010,TFS 2008,VS ALM

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Installing SharePoint 2010 and PowerPivot for SharePoint on Windows 7

- by smisner

Many people like me want (or need) to do their business intelligence development work on a laptop. As someone who frequently speaks at various events or teaches classes on all subjects related to the Microsoft business intelligence stack, I need a way to run multiple server products on my laptop with reasonable performance. Once upon a time, that requirement meant only that I had to load the current version of SQL Server and the client tools of choice. In today's post, I'll review my latest experience with trying to make the newly released Microsoft BI products work with a Windows 7 operating system.The entrance of Microsoft Office SharePoint Server 2007 into the BI stack complicated matters and I started using Virtual Server to establish a "suitable" environment. As part of the team that delivered a lot of education as part of the Yukon pre-launch activities (that would be SQL Server 2005 for the uninitiated), I was working with four - yes, four - virtual servers. That was a pretty brutal workload for a 2GB laptop, which worked if I was very, very careful. It could also be a finicky and unreliable configuration as I learned to my dismay at one TechEd session several years ago when I had to reboot a very carefully cached set of servers just minutes before my session started. Although it worked, it came back to life very, very slowly much to the displeasure of the audience. They couldn't possibly have been less pleased than me.At that moment, I resolved to get the beefiest environment I could afford and consolidate to a single virtual server. Enter the 4GB 64-bit laptop to preserve my sanity and my livelihood. Likewise, for SQL Server 2008, I managed to keep everything within a single virtual server and I could function reasonably well with this approach.Now we have SQL Server 2008 R2 plus Office SharePoint Server 2010. That means a 64-bit operating system. Period. That means no more Virtual Server. That means I must use Hyper-V or another alternative. I've heard alternatives exist, but my few dabbles in this area did not yield positive results. It might have been just me having issues rather than any failure of those technologies to adequately support the requirements.My first run at working with the new BI stack configuration was to set up a 64-bit 4GB laptop with a dual-boot to run Windows Server 2008 R2 with Hyper-V. However, I was generally not happy with running Windows Server 2008 R2 on my laptop. For one, I couldn't put it into sleep mode, which is helpful if I want to prepare for a presentation beforehand and then walk to the podium without the need to hold my laptop in its open state along the way (my strategy at the TechEd session long, long ago). Secondly, it was finicky with projectors. I had issues from time to time and while I always eventually got it to work, I didn't appreciate those nerve-wracking moments wondering whether this would be the time that it wouldn't work.Somewhere along the way, I learned that it was possible to load SharePoint 2010 in a Windows 7 which piqued my interest. I had just acquired a new laptop running Windows 7 64-bit, and thought surely running the BI stack natively on my laptop must be better than running Hyper-V. (I have not tried booting to Hyper-V VHD yet, but that's on my list of things to try so the jury of one is still out on this approach.) Recently, I had to build up a server with the RTM versions of SQL Server 2008 R2 and Sharepoint Server 2010 and decided to follow suit on my Windows 7 Ultimate 64-bit laptop. The process is slightly different, but I'm happy to report that it IS possible, although I had some fits and starts along the way.DISCLAIMER: These products are NOT intended to be run in production mode on the Windows 7 operating system. The configuration described in this post is strictly for development or learning purposes and not supported by Microsoft. If you have trouble, you will NOT get help from them. I might be able to help, but I provide no guarantees of my ability or availablity to help. I won't provide the step-by-step instructions in this post as there are other resources that provide these details, but I will provide an overview of my approach, point you to the relevant resources, describe some of the problems I encountered, and explain how I addressed those problems to achieve my desired goal.Because my goal was not simply to set up SharePoint Server 2010 on my laptop, but specifically PowerPivot for SharePoint, I started out by referring to the installation instructions at the PowerPiovt-Info site, but mainly to confirm that I was performing steps in the proper sequence. I didn't perform the steps in Part 1 because those steps are applicable only to a server operating system which I am not running on my laptop. Then, the instructions in Part 2, won't work exactly as written for the same reason. Instead, I followed the instructions on MSDN, Setting Up the Development Environment for SharePoint 2010 on Windows Vista, Windows 7, and Windows Server 2008. In general, I found the following differences in installation steps from the steps at PowerPivot-Info:You must copy the SharePoint installation media to the local drive so that you can edit the config.xml to allow installation on a Windows client.You also have to manually install the prerequisites. The instructions provides links to each item that you must manually install and provides a command-line instruction to execute which enables required Windows features.I will digress for a moment to save you some grief in the sequence of steps to perform. I discovered later that a missing step in the MSDN instructions is to install the November CTP Reporting Services add-in for SharePoint. When I went to test my SharePoint site (I believe I tested after I had a successful PowerPivot installation), I ran into the following error: Could not load file or assembly 'RSSharePointSoapProxy, Version=10.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. The system cannot find the file specified. I was rather surprised that Reporting Services was required. Then I found an article by Alan le Marquand, Working Together: SQL Server 2008 R2 Reporting Services Integration in SharePoint 2010,that instructed readers to install the November add-in. My first reaction was, "Really?!?" But I confirmed it in another TechNet article on hardware and software requirements for SharePoint Server 2010. It doesn't refer explicitly to the November CTP but following the link took me there. (Interestingly, I retested today and there's no longer any reference to the November CTP. Here's the link to download the latest and greatest Reporting Services Add-in for SharePoint Technologies 2010.) You don't need to download the add-in anymore if you're doing a regular server-based installation of SharePoint because it installs as part of the prerequisites automatically.When it was time to start the installation of SharePoint, I deviated from the MSDN instructions and from the PowerPivot-Info instructions:On the Choose the installation you want page of the installation wizard, I chose Server Farm.On the Server Type page, I chose Complete.At the end of the installation, I did not run the configuration wizard.Returning to the PowerPivot-Info instructions, I tried to follow the instructions in Part 3 which describe installing SQL Server 2008 R2 with the PowerPivot option. These instructions tell you to choose the New Server option on the Setup Role page where you add PowerPivot for SharePoint. However, I ran into problems with this approach and got installation errors at the end.It wasn't until much later as I was investigating an error that I encountered Dave Wickert's post that installing PowerPivot for SharePoint on Windows 7 is unsupported. Uh oh. But he did want to hear about it if anyone succeeded, so I decided to take the plunge. Perseverance paid off, and I can happily inform Dave that it does work so far. I haven't tested absolutely everything with PowerPivot for SharePoint but have successfully deployed a workbook and viewed the PowerPivot Management Dashboard. I have not yet tested the data refresh feature, but I have installed. Continue reading to see how I accomplished my objective.I unintalled SQL Server 2008 R2 and started again. I had different problems which I don't recollect now. However, I uninstalled again and approached installation from a different angle and my next attempt succeeded. The downside of this approach is that you must do all of the things yourself that are done automatically when you install PowerPivot as a new server. Here are the steps that I followed:Install SQL Server 2008 R2 to get a database engine instance installed.Run the SharePoint configuration wizard to set up the SharePoint databases.In Central Administration, create a Web application using classic mode authentication as per a TechNet article on PowerPivot Authentication and Authorization.Then I followed the steps I found at How to: Install PowerPivot for SharePoint on an Existing SharePoint Server. Especially important to note - you must launch setup by using Run as administrator. I did not have to manually deploy the PowerPivot solution as the instructions specify, but it's good to know about this step because it tells you where to look in Central Administration to confirm a successful deployment.I did spot some incorrect steps in the instructions (at the time of this writing) in How To: Configure Stored Credentials for PowerPivot Data Refresh. Specifically, in the section entitled Step 1: Create a target application and set the credentials, both steps 10 and 12 are incorrect. They tell you to provide an actual Windows user name and password on the page where you are simply defining the prompts for your application in the Secure Store Service. To add the Windows user name and password that you want to associate with the application - after you have successfully created the target application - you select the target application and then click Set credentials in the ribbon.Lastly, I followed the instructions at How to: Install Office Data Connectivity Components on a PowerPivot server. However, I have yet to test this in my current environment.I did have several stops and starts throughout this process and edited those out to spare you from reading non-essential information. I believe the explanation I have provided here accurately reflect the steps I followed to produce a working configuration. If you follow these steps and get a different result, please let me know so that together we can work through the issue and correct these instructions. I'm sure there are many other folks in the Microsoft BI community that will appreciate the ability to set up the BI stack in a Windows 7 environment for development or learning purposes. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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First round playing with Memcached

- by Shaun

To be honest I have not been very interested in the caching before I’m going to a project which would be using the multi-site deployment and high connection and concurrency and very sensitive to the user experience. That means we must cache the output data for better performance. After looked for the Internet I finally focused on the Memcached. What’s the Memcached? I think the description on its main site gives us a very good and simple explanation. Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load. Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering. Memcached is simple yet powerful. Its simple design promotes quick deployment, ease of development, and solves many problems facing large data caches. Its API is available for most popular languages. The original Memcached was built on *nix system are is being widely used in the PHP world. Although it’s not a problem to use the Memcached installed on *nix system there are some windows version available fortunately. Since we are WISC (Windows – IIS – SQL Server – C#, which on the opposite of LAMP) it would be much easier for us to use the Memcached on Windows rather than *nix. I’m using the Memcached Win X64 version provided by NorthScale. There are also the x86 version and other operation system version. Install Memcached Unpack the Memcached file to a folder on the machine you want it to be installed, we can see that there are only 3 files and the main file should be the “memcached.exe”. Memcached would be run on the server as a service. To install the service just open a command windows and navigate to the folder which contains the “memcached.exe”, let’s say “C:\Memcached\”, and then type “memcached.exe -d install”. If you are using Windows Vista and Windows 7 system please be execute the command through the administrator role. Right-click the command item in the start menu and use “Run as Administrator”, otherwise the Memcached would not be able to be installed successfully. Once installed successful we can type “memcached.exe -d start” to launch the service. Now it’s ready to be used. The default port of Memcached is 11211 but you can change it through the command argument. You can find the help by typing “memcached -h”. Using Memcached Memcahed has many good and ready-to-use providers for vary program language. After compared and reviewed I chose the Memcached Providers. It’s built based on another 3rd party Memcached client named enyim.com Memcached Client. The Memcached Providers is very simple to set/get the cached objects through the Memcached servers and easy to be configured through the application configuration file (aka web.config and app.config). Let’s create a console application for the demonstration and add the 3 DLL files from the package of the Memcached Providers to the project reference. Then we need to add the configuration for the Memcached server. Create an App.config file and firstly add the section on top of it. Here we need three sections: the section for Memcached Providers, for enyim.com Memcached client and the log4net. 1: <configSections> 2: <section name="cacheProvider" 3: type="MemcachedProviders.Cache.CacheProviderSection, MemcachedProviders" 4: allowDefinition="MachineToApplication" 5: restartOnExternalChanges="true"/> 6: <sectionGroup name="enyim.com"> 7: <section name="memcached" 8: type="Enyim.Caching.Configuration.MemcachedClientSection, Enyim.Caching"/> 9: </sectionGroup> 10: <section name="log4net" 11: type="log4net.Config.Log4NetConfigurationSectionHandler,log4net"/> 12: </configSections> Then we will add the configuration for 3 of them in the App.config file. The Memcached server information would be defined under the enyim.com section since it will be responsible for connect to the Memcached server. Assuming I installed the Memcached on two servers with the default port, the configuration would be like this. 1: <enyim.com> 2: <memcached> 3: <servers> 4:  5: <add address="192.168.0.149" port="11211"/> 6: <add address="10.10.20.67" port="11211"/> 7: </servers> 8: <socketPool minPoolSize="10" maxPoolSize="100" connectionTimeout="00:00:10" deadTimeout="00:02:00"/> 9: </memcached> 10: </enyim.com> Memcached supports the multi-deployment which means you can install the Memcached on the servers as many as you need. The protocol of the Memcached responsible for routing the cached objects into the proper server. So it’s very easy to scale-out your system by Memcached. And then define the Memcached Providers configuration. The defaultExpireTime indicates how long the objected cached in the Memcached would be expired, the default value is 2000 ms. 1: <cacheProvider defaultProvider="MemcachedCacheProvider"> 2: <providers> 3: <add name="MemcachedCacheProvider" 4: type="MemcachedProviders.Cache.MemcachedCacheProvider, MemcachedProviders" 5: keySuffix="_MySuffix_" 6: defaultExpireTime="2000"/> 7: </providers> 8: </cacheProvider> The last configuration would be the log4net. 1: <log4net> 2:  3: <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender"> 4: <layout type="log4net.Layout.PatternLayout"> 5: <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline"/> 6: </layout> 7: </appender> 8:  9:  10: <root> 11: <priority value="WARN"/> 12: <appender-ref ref="ConsoleAppender"> 13: <filter type="log4net.Filter.LevelRangeFilter"> 14: <levelMin value="WARN"/> 15: <levelMax value="FATAL"/> 16: </filter> 17: </appender-ref> 18: </root> 19: </log4net> Get, Set and Remove the Cached Objects Once we finished the configuration it would be very simple to consume the Memcached servers. The Memcached Providers gives us a static class named DistCache that can be used to operate the Memcached servers. Get<T>: Retrieve the cached object from the Memcached servers. If failed it will return null or the default value. Add: Add an object with a unique key into the Memcached servers. Assuming that we have an operation that retrieve the email from the name which is time consuming. This is the operation that should be cached. The method would be like this. I utilized Thread.Sleep to simulate the long-time operation. 1: static string GetEmailByNameSlowly(string name) 2: { 3: Thread.Sleep(2000); 4: return name + "@ethos.com.cn"; 5: } Then in the real retrieving method we will firstly check whether the name, email information had been searched previously and cached. If yes we will just return them from the Memcached, otherwise we will invoke the slowly method to retrieve it and then cached. 1: static string GetEmailByName(string name) 2: { 3: var email = DistCache.Get<string>(name); 4: if (string.IsNullOrEmpty(email)) 5: { 6: Console.WriteLine("==> The name/email not be in memcached so need slow loading. (name = {0})==>", name); 7: email = GetEmailByNameSlowly(name); 8: DistCache.Add(name, email); 9: } 10: else 11: { 12: Console.WriteLine("==> The name/email had been in memcached. (name = {0})==>", name); 13: } 14: return email; 15: } Finally let’s finished the calling method and execute. 1: static void Main(string[] args) 2: { 3: var name = string.Empty; 4: while (name != "q") 5: { 6: Console.Write("==> Please enter the name to find the email: "); 7: name = Console.ReadLine(); 8: 9: var email = GetEmailByName(name); 10: Console.WriteLine("==> The email of {0} is {1}.", name, email); 11: } 12: } The first time I entered “ziyanxu” it takes about 2 seconds to get the email since there’s nothing cached. But the next time I entered “ziyanxu” it returned very quickly from the Memcached. Summary In this post I explained a bit on why we need cache, what’s Memcached and how to use it through the C# application. The example is fairly simple but hopefully demonstrated on how to use it. Memcached is very easy and simple to be used since it gives you the full opportunity to consider what, when and how to cache the objects. And when using Memcached you don’t need to consider the cache servers. The Memcached would be like a huge object pool in front of you. The next step I’m thinking now are: What kind of data should be cached? And how to determined the key? How to implement the cache as a layer on top of the business layer so that the application will not notice that the cache is there. How to implement the cache by AOP so that the business logic no need to consider the cache. I will investigate on them in the future and will share my thoughts and results. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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Adventures in MVVM – My ViewModel Base

- by Brian Genisio's House Of Bilz

More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it. I have yet to find an MVVM framework that does everything I want it to without doing too much. Don’t get me wrong… there are some good frameworks out there. I just like to pick and choose things that make sense for me. I’d also like to add that some of these features only work in WPF. As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world. I have had several conversations with people about the problems I have solved using this ViewModel base. A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”. What followed from those ideas was a ViewModel base class that I take with me and use in my projects. It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model. Without all three, you don’t have MVVM. But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands. The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method. To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you. The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix. You are left to be expressive with your behavior without the plumbing. If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } } Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface). There have been many attempts to make this more automatic. My base class includes one option. There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field. The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious. Too much plumbing. My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } } Strongly Typed Property Getters/Setters It turns out that we can do better than that. We are using a strongly typed language where the use of “Magic Strings” is often frowned upon. Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } } Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically. This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW) By calling Set(“Foo”, 1), you have now created a dynamic property called Foo. It can be bound against like any static property. The opportunities are endless. One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user. The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already. Why not exploit it? Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" /> Default Property Values The Get() method also allows for default properties to be set. Don’t set them in the constructor. Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} } Derived Properties This is something I blogged about a while back in more detail. This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed. This, to me, is backwards. It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this. What we really want to do is invert the dependency. Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } } Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property. When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } } Command CanExecute Change Notification Back to Commands. One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated. I wanted to wait until we got past a few concepts before explaining this behavior. You can use the same mechanism here to fire off the change. In the CanExecute_ method, declare the property that it depends upon. When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command. The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } } Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer. You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } } What About Silverlight? Some of the features in this base class only work in WPF. As of version 4, Silverlight does not support binding to dynamic properties. This, in my opinion, is a HUGE limitation. Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby. Does this mean that the base class will not work in Silverlight? No. Many of the features outlined in this article WILL work. All of the property abstractions are functional, as long as you refer to them statically in the View. This, of course, means that the automatic command hook-up doesn’t work in Silverlight. You need to plumb it to a static property in order for the Silverlight View to bind to it. Can I has a dynamic property in SL5? Good to go? So, that concludes the feature explanation of my ViewModel base class. Feel free to take it, fork it, whatever. It is hosted on CodePlex. When I find other useful additions, I will add them to the public repository. I use this base class every day. It is mature, and well tested. If, however, you find any problems with it, please let me know! Also, feel free to suggest patches to me via the CodePlex site. :)

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SQL SERVER – Guest Post – Jonathan Kehayias – Wait Type – Day 16 of 28

- by pinaldave

Jonathan Kehayias (Blog | Twitter) is a MCITP Database Administrator and Developer, who got started in SQL Server in 2004 as a database developer and report writer in the natural gas industry. After spending two and a half years working in TSQL, in late 2006, he transitioned to the role of SQL Database Administrator. His primary passion is performance tuning, where he frequently rewrites queries for better performance and performs in depth analysis of index implementation and usage. Jonathan blogs regularly on SQLBlog, and was a coauthor of Professional SQL Server 2008 Internals and Troubleshooting. On a personal note, I think Jonathan is extremely positive person. In every conversation with him I have found that he is always eager to help and encourage. Every time he finds something needs to be approved, he has contacted me without hesitation and guided me to improve, change and learn. During all the time, he has not lost his focus to help larger community. I am honored that he has accepted to provide his views on complex subject of Wait Types and Queues. Currently I am reading his series on Extended Events. Here is the guest blog post by Jonathan: SQL Server troubleshooting is all about correlating related pieces of information together to indentify where exactly the root cause of a problem lies. In my daily work as a DBA, I generally get phone calls like, “So and so application is slow, what’s wrong with the SQL Server.” One of the funny things about the letters DBA is that they go so well with Default Blame Acceptor, and I really wish that I knew exactly who the first person was that pointed that out to me, because it really fits at times. A lot of times when I get this call, the problem isn’t related to SQL Server at all, but every now and then in my initial quick checks, something pops up that makes me start looking at things further. The SQL Server is slow, we see a number of tasks waiting on ASYNC_IO_COMPLETION, IO_COMPLETION, or PAGEIOLATCH_* waits in sys.dm_exec_requests and sys.dm_exec_waiting_tasks. These are also some of the highest wait types in sys.dm_os_wait_stats for the server, so it would appear that we have a disk I/O bottleneck on the machine. A quick check of sys.dm_io_virtual_file_stats() and tempdb shows a high write stall rate, while our user databases show high read stall rates on the data files. A quick check of some performance counters and Page Life Expectancy on the server is bouncing up and down in the 50-150 range, the Free Page counter consistently hits zero, and the Free List Stalls/sec counter keeps jumping over 10, but Buffer Cache Hit Ratio is 98-99%. Where exactly is the problem? In this case, which happens to be based on a real scenario I faced a few years back, the problem may not be a disk bottleneck at all; it may very well be a memory pressure issue on the server. A quick check of the system spec’s and it is a dual duo core server with 8GB RAM running SQL Server 2005 SP1 x64 on Windows Server 2003 R2 x64. Max Server memory is configured at 6GB and we think that this should be enough to handle the workload; or is it? This is a unique scenario because there are a couple of things happening inside of this system, and they all relate to what the root cause of the performance problem is on the system. If we were to query sys.dm_exec_query_stats for the TOP 10 queries, by max_physical_reads, max_logical_reads, and max_worker_time, we may be able to find some queries that were using excessive I/O and possibly CPU against the system in their worst single execution. We can also CROSS APPLY to sys.dm_exec_sql_text() and see the statement text, and also CROSS APPLY sys.dm_exec_query_plan() to get the execution plan stored in cache. Ok, quick check, the plans are pretty big, I see some large index seeks, that estimate 2.8GB of data movement between operators, but everything looks like it is optimized the best it can be. Nothing really stands out in the code, and the indexing looks correct, and I should have enough memory to handle this in cache, so it must be a disk I/O problem right? Not exactly! If we were to look at how much memory the plan cache is taking by querying sys.dm_os_memory_clerks for the CACHESTORE_SQLCP and CACHESTORE_OBJCP clerks we might be surprised at what we find. In SQL Server 2005 RTM and SP1, the plan cache was allowed to take up to 75% of the memory under 8GB. I’ll give you a second to go back and read that again. Yes, you read it correctly, it says 75% of the memory under 8GB, but you don’t have to take my word for it, you can validate this by reading Changes in Caching Behavior between SQL Server 2000, SQL Server 2005 RTM and SQL Server 2005 SP2. In this scenario the application uses an entirely adhoc workload against SQL Server and this leads to plan cache bloat, and up to 4.5GB of our 6GB of memory for SQL can be consumed by the plan cache in SQL Server 2005 SP1. This in turn reduces the size of the buffer cache to just 1.5GB, causing our 2.8GB of data movement in this expensive plan to cause complete flushing of the buffer cache, not just once initially, but then another time during the queries execution, resulting in excessive physical I/O from disk. Keep in mind that this is not the only query executing at the time this occurs. Remember the output of sys.dm_io_virtual_file_stats() showed high read stalls on the data files for our user databases versus higher write stalls for tempdb? The memory pressure is also forcing heavier use of tempdb to handle sorting and hashing in the environment as well. The real clue here is the Memory counters for the instance; Page Life Expectancy, Free List Pages, and Free List Stalls/sec. The fact that Page Life Expectancy is fluctuating between 50 and 150 constantly is a sign that the buffer cache is experiencing constant churn of data, once every minute to two and a half minutes. If you add to the Page Life Expectancy counter, the consistent bottoming out of Free List Pages along with Free List Stalls/sec consistently spiking over 10, and you have the perfect memory pressure scenario. All of sudden it may not be that our disk subsystem is the problem, but is instead an innocent bystander and victim. Side Note: The Page Life Expectancy counter dropping briefly and then returning to normal operating values intermittently is not necessarily a sign that the server is under memory pressure. The Books Online and a number of other references will tell you that this counter should remain on average above 300 which is the time in seconds a page will remain in cache before being flushed or aged out. This number, which equates to just five minutes, is incredibly low for modern systems and most published documents pre-date the predominance of 64 bit computing and easy availability to larger amounts of memory in SQL Servers. As food for thought, consider that my personal laptop has more memory in it than most SQL Servers did at the time those numbers were posted. I would argue that today, a system churning the buffer cache every five minutes is in need of some serious tuning or a hardware upgrade. Back to our problem and its investigation: There are two things really wrong with this server; first the plan cache is excessively consuming memory and bloated in size and we need to look at that and second we need to evaluate upgrading the memory to accommodate the workload being performed. In the case of the server I was working on there were a lot of single use plans found in sys.dm_exec_cached_plans (where usecounts=1). Single use plans waste space in the plan cache, especially when they are adhoc plans for statements that had concatenated filter criteria that is not likely to reoccur with any frequency. SQL Server 2005 doesn’t natively have a way to evict a single plan from cache like SQL Server 2008 does, but MVP Kalen Delaney, showed a hack to evict a single plan by creating a plan guide for the statement and then dropping that plan guide in her blog post Geek City: Clearing a Single Plan from Cache. We could put that hack in place in a job to automate cleaning out all the single use plans periodically, minimizing the size of the plan cache, but a better solution would be to fix the application so that it uses proper parameterized calls to the database. You didn’t write the app, and you can’t change its design? Ok, well you could try to force parameterization to occur by creating and keeping plan guides in place, or we can try forcing parameterization at the database level by using ALTER DATABASE <dbname> SET PARAMETERIZATION FORCED and that might help. If neither of these help, we could periodically dump the plan cache for that database, as discussed as being a problem in Kalen’s blog post referenced above; not an ideal scenario. The other option is to increase the memory on the server to 16GB or 32GB, if the hardware allows it, which will increase the size of the plan cache as well as the buffer cache. In SQL Server 2005 SP1, on a system with 16GB of memory, if we set max server memory to 14GB the plan cache could use at most 9GB [(8GB*.75)+(6GB*.5)=(6+3)=9GB], leaving 5GB for the buffer cache. If we went to 32GB of memory and set max server memory to 28GB, the plan cache could use at most 16GB [(8*.75)+(20*.5)=(6+10)=16GB], leaving 12GB for the buffer cache. Thankfully we have SQL Server 2005 Service Pack 2, 3, and 4 these days which include the changes in plan cache sizing discussed in the Changes to Caching Behavior between SQL Server 2000, SQL Server 2005 RTM and SQL Server 2005 SP2 blog post. In real life, when I was troubleshooting this problem, I spent a week trying to chase down the cause of the disk I/O bottleneck with our Server Admin and SAN Admin, and there wasn’t much that could be done immediately there, so I finally asked if we could increase the memory on the server to 16GB, which did fix the problem. It wasn’t until I had this same problem occur on another system that I actually figured out how to really troubleshoot this down to the root cause. I couldn’t believe the size of the plan cache on the server with 16GB of memory when I actually learned about this and went back to look at it. SQL Server is constantly telling a story to anyone that will listen. As the DBA, you have to sit back and listen to all that it’s telling you and then evaluate the big picture and how all the data you can gather from SQL about performance relate to each other. One of the greatest tools out there is actually a free in the form of Diagnostic Scripts for SQL Server 2005 and 2008, created by MVP Glenn Alan Berry. Glenn’s scripts collect a majority of the information that SQL has to offer for rapid troubleshooting of problems, and he includes a lot of notes about what the outputs of each individual query might be telling you. When I read Pinal’s blog post SQL SERVER – ASYNC_IO_COMPLETION – Wait Type – Day 11 of 28, I noticed that he referenced Checking Memory Related Performance Counters in his post, but there was no real explanation about why checking memory counters is so important when looking at an I/O related wait type. I thought I’d chat with him briefly on Google Talk/Twitter DM and point this out, and offer a couple of other points I noted, so that he could add the information to his blog post if he found it useful. Instead he asked that I write a guest blog for this. I am honored to be a guest blogger, and to be able to share this kind of information with the community. The information contained in this blog post is a glimpse at how I do troubleshooting almost every day of the week in my own environment. SQL Server provides us with a lot of information about how it is running, and where it may be having problems, it is up to us to play detective and find out how all that information comes together to tell us what’s really the problem. This blog post is written by Jonathan Kehayias (Blog | Twitter). Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, Pinal Dave, PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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Issuing Current Time Increments in StreamInsight (A Practical Example)

The issuing of a Current Time Increment, Cti, in StreamInsight is very definitely one of the most important concepts to learn if you want your Streams to be responsive. A full discussion of how to issue Ctis is beyond the scope of this article but a very good explanation in addition to Books Online can be found in these three articles by a member of the StreamInsight team at Microsoft, Ciprian Gerea. Time in StreamInsight Series http://blogs.msdn.com/b/streaminsight/archive/2010/07/23/time-in-streaminsight-i.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/07/30/time-in-streaminsight-ii.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/08/03/time-in-streaminsight-iii.aspx A lot of the problems I see with unresponsive or stuck streams on the MSDN Forums are to do with how Ctis are enqueued or in a lot of cases not enqueued. If you enqueue events and never enqueue a Cti then StreamInsight will be perfectly happy. You, on the other hand, will never see data on the output as you have not told StreamInsight to flush the stream. This article deals with a specific implementation problem I had recently whilst working on a StreamInsight project. I look at some possible options and discuss why they would not work before showing the way I solved the problem. The stream of data I was dealing with on this project was very bursty that is to say when events were flowing they came through very quickly and in large numbers (1000 events/sec), but when the stream calmed down it could be a few seconds between each event. When enqueuing events into the StreamInsight engne it is best practice to do so with a StartTime that is given to you by the system producing the event . StreamInsight processes events and it doesn't matter whether those events are being pushed into the engine by a source system or the events are being read from something like a flat file in a directory somewhere. You can apply the same logic and temporal algebra to both situations. Reading from a file is an excellent example of where the time of the event on the source itself is very important. We could be reading that file a long time after it was written. Being able to read the StartTime from the events allows us to define windows that will hold the correct sets of events. I was able to do this with my stream but this is where my problems started. Below is a very simple script to create a SQL Server table and populate it with sample data that will show exactly the problem I had. CREATE TABLE [dbo].[t] ( [c1] [int] PRIMARY KEY, [c2] [datetime] NULL ) INSERT t VALUES (1,'20100810'),(2,'20100810'),(3,'20100810') Column c2 defines the StartTime of the event on the source and as you can see the values in all 3 rows of data is the same. If we read Ciprian’s articles we know that we can define how Ctis get injected into the stream in 3 different places The Stream Definition The Input Factory The Input Adapter I personally have always been a fan of enqueing Ctis through the factory. Below is code typical of what I would use to do this On the class itself I do some inheriting public class SimpleInputFactory : ITypedInputAdapterFactory<SimpleInputConfig>, ITypedDeclareAdvanceTimeProperties<SimpleInputConfig> And then I implement the following function public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.FromTicks(-1)), AdvanceTimePolicy.Adjust); } The configInfo .CtiFrequency property is a value I pass through to define after how many events I want a Cti to be injected and this in turn will flush through the stream of data. I usually pass a value of 1 for this setting. The second parameter determines the CTI timestamp in terms of a delay relative to the events. -1 ticks in the past results in 1 tick in the future, i.e., ahead of the event. The problem with this method though is that if consecutive events have the same StartTime then only one of those events will be enqueued. In this example I use the following to define how I assign the StartTime of my events currEvent.StartTime = (DateTimeOffset)dt.c2; If I go ahead and run my StreamInsight process with this configuration i can see on the output adapter that two events have been removed To see this in a little more depth I can use the StreamInsight Debugger and see what happens internally. What is happening here is that the first event arrives and a Cti is injected with a time of 1 tick after the StartTime of that event (Also the EndTime of the event). The second event arrives and it has a StartTime of before the Cti and even though we specified AdvanceTimePolicy.Adjust on the factory we know that a point event can never be adjusted like this and the event is dropped. The same happens for the third event as well (The second and third events get trumped by the Cti). For a more detailed discussion of why this happens look here http://www.sqlis.com/sqlis/post/AdvanceTimePolicy-and-Point-Event-Streams-In-StreamInsight.aspx We end up with a single event being pushed into the output adapter and our result now makes sense. The next way I tried to solve this problem by changing the value of the second parameter to TimeSpan.Zero Here is how my factory code now looks public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.Zero), AdvanceTimePolicy.Adjust); } What I am doing here is declaring a policy that says inject a Cti together with every event and stamp it with a StartTime that is equal to the start time of the event itself (TimeSpan.Zero). This method has plus points as well as a downside. The upside is that no events will be lost by having the same StartTime as previous events. The Downside is that because the Cti is declared with the StartTime of the event itself then it does not actually flush that particular event because in the StreamInsight algebra, a Cti commits only those events that occurred strictly before them. To flush the events we need a Cti to be enqueued with a greater StartTime than the events themselves. Here is what happened when I ran this configuration As you can see all we got through was the Cti and none of the events. The debugger output shows the stamps on the Cti and the events themselves. Because the Cti issued has the same timestamp (StartTime) as the events then none of the events get flushed. I was nearly there but not quite. Because my stream was bursty it was possible that the next event would not come along for a few seconds and this was far too long for an event to be enqueued and not be flushed to the output adapter. I needed another solution. Two possible solutions crossed my mind although only one of them made sense when I explored it some more. Where multiple events have the same StartTime I could add 1 tick to the first event, two to the second, three to third etc thereby giving them unique StartTime values. Add a timer to manually inject Ctis The problem with the first implementation is that I would be giving the events a new StartTime. This would cause me the following problems If I want to define windows over the stream then some events may not be captured in the right windows and therefore any calculations on those windows I did would be wrong What would happen if we had 10,000 events with the same StartTime? I would enqueue them with StartTime + n ticks. Along comes a genuine event with a StartTime of the very first event + 1 tick. It is now too far in the past as far as my stream is concerned and it would be dropped. Not what I would want to do at all. I decided then to look at the Timer based solution I created a timer on my input adapter that elapsed every 200ms. private Timer tmr; public SimpleInputAdapter(SimpleInputConfig configInfo) { ctx = new SimpleTimeExtractDataContext(configInfo.ConnectionString); this.configInfo = configInfo; tmr = new Timer(200); tmr.Elapsed += new ElapsedEventHandler(t_Elapsed); tmr.Enabled = true; } void t_Elapsed(object sender, ElapsedEventArgs e) { ts = DateTime.Now - dtCtiIssued; if (ts.TotalMilliseconds >= 200 && TimerIssuedCti == false) { EnqueueCtiEvent(System.DateTime.Now.AddTicks(-100)); TimerIssuedCti = true; } } In the t_Elapsed event handler I find out the difference in time between now and when the last event was processed (dtCtiIssued). I then check to see if that is greater than or equal to 200ms and if the last issuing of a Cti was done by the timer or by a genuine event (TimerIssuedCti). If I didn’t do this check then I would enqueue a Cti every time the timer elapsed which is not something I wanted. If the difference between the two times is greater than or equal to 500ms and the last event enqueued was by a real event then I issue a Cti through the timer to flush the event Queue, otherwise I do nothing. When I enqueue the Ctis into my stream in my ProduceEvents method I also set the values of dtCtiIssued and TimerIssuedCti currEvent = CreateInsertEvent(); currEvent.StartTime = (DateTimeOffset)dt.c2; TimerIssuedCti = false; dtCtiIssued = currEvent.StartTime; If I go ahead and run this configuration I see the following in my output. As we can see the first Cti gets enqueued as before but then another is enqueued by the timer and because this has a later timestamp it flushes the enqueued events through the engine. Conclusion Hopefully this has shown how the enqueuing of Ctis can have a dramatic effect on the responsiveness of your output in StreamInsight. Understanding the temporal nature of the product is for me one of the most important things you can learn. I have attached my solution for the demos. It is all in one project and testing each variation is a simple matter of commenting and un-commenting the parts in the code we have been dealing with here.

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Oracle Coherence & Oracle Service Bus: REST API Integration

- by Nino Guarnacci

This post aims to highlight one of the features found in Oracle Coherence which allows it to be easily added and integrated inside a wider variety of projects. The features in question are the REST API exposed by the Coherence nodes, with which you can interact in the wider mode in memory data grid.Oracle Coherence and Oracle Service Bus are natively integrated through a feature found in the Oracle Service Bus, which allows you to use the coherence grid cache during the configuration phase of a business service. This feature allows you to use an intermediate layer of cache to retrieve the answers from previous invocations of the same service, without necessarily having to invoke the real business service again. Directly from the web console of Oracle Service Bus, you can decide the policies of eviction of the objects / answers and define the discriminating parameters that identify their uniqueness.The coherence REST APIs, however, allow you to integrate both products for other necessities enabling realization of new architectures design. Consider coherence’s node as a simple service which interoperates through the stardard services and in particular REST (with JSON and XML). Thinking of coherence as a company’s shared service, able to have an implementation of a centralized “map and reduce” which you can access by a huge variety of protocols (transport and envelopes).An amazing step forward for those who still imagine connectors and code. This type of integration does not require writing custom code or complex implementation to be self-supported. The added value is made unique by the incredible value of both products independently, and still more out of their simple and robust integration.As already mentioned this scenario discovers a hidden new door behind the columns of these two products. The door leads to new ideas and perspectives for enterprise architectures that increasingly wink to next-generation applications: simple and dynamic, perhaps towards the mobile and web 2.0.Below, a small and simple demo useful to demonstrate how easily is to integrate these two products using the Coherence REST API. This demo is also intended to imagine new enterprise architectures using this approach.The idea is to create a centralized system of alerting, fed easily from any company’s application, regardless of the technology with which they were built . Then use a representation standard protocol: RSS, using a service exposed by the service bus; So you can browse and search only the alerts that you are interested on, by category, author, title, date, etc etc.. The steps needed to implement this system are very simple and very few. Here they are listed below and described to be easily replicated within your environment. I would remind you that the demo is only meant to demonstrate how easily is to integrate Oracle Coherence and the Oracle Service Bus, and stimulate your imagination to new technological approaches.1) Install the two products: In this demo used (if necessary, consult the installation guides of 2 products) - Oracle Service Bus ver. 11.1.1.5.0 http://www.oracle.com/technetwork/middleware/service-bus/downloads/index.html - Oracle Coherence ver. 3.7.1 http://www.oracle.com/technetwork/middleware/coherence/downloads/index.html 2) Because you choose to create a centralized alerting system, we need to define a structure type containing some alerting attributes useful to preserve and organize the information of the various alerts sent by the different applications. Here, then it was built a java class named Alert containing the canonical properties of an alarm information:- Title- Description- System- Time- Severity 3) Therefore, we need to create two configuration files for the coherence node, in order to save the Alert objects within the grid, through the rest/http protocol (more than the native API for Java, C + +, C,. Net). Here are the two minimal configuration files for Coherence:coherence-rest-config.xml resty-server-config.xml This minimum configuration allows me to use a distributed cache named "alerts" that can also be accessed via http - rest on the host "localhost" over port "8080", objects are of type “oracle.cohsb.Alert”. 4) Below a simple Java class that represents the type of alert messages: 5) At this point we just need to startup our coherence node, able to listen on http protocol to manage the “alerts” cache, which will receive incoming XML or JSON objects of type Alert. Remember to include in the classpath of the coherence node, the Alert java class and the following coherence libraries and configuration files: At this point, just run the coherence class node “com.tangosol.net.DefaultCacheServer”advising you to set the following parameters:-Dtangosol.coherence.log.level=9 -Dtangosol.coherence.log=stdout -Dtangosol.coherence.cacheconfig=[PATH_TO_THE_FILE]\resty-server-config.xml 6) Let's create a procedure to test our configuration of Coherence and in order to insert some custom alerts in our cache. The technology with which you want to achieve this functionality is fully not considerable: Javascript, Python, Ruby, Scala, C + +, Java.... Because the protocol to communicate with Coherence is simply HTTP / JSON or XML. For this little demo i choose Java: A method to send/put the alert to the cache: A method to query and view the content of the cache: Finally the main method that execute our methods: No special library added in the classpath for our class (json struct static defined), when it will be executed, it asks some information such as title, description,... in order to compose and send an alert to the cache and then it will perform an inquiry, to the same cache. At this point, a good exercise at this point, may be to create the same procedure using other technologies, such as a simple html page containing some JavaScript code, and then using Python, Ruby, and so on.7) Now we are ready to start configuring the Oracle Service Bus in order to integrate the two products. First integrate the internal alerting system of Oracle Service Bus with our centralized alerting system based on coherence node. This ensures that by monitoring, or directly from within our Proxy Message Flow, we can throw alerts and save them directly into the Coherence node. To do this I choose to use the jms technology, natively present inside the Oracle Weblogic / Service Bus. Access to the Oracle WebLogic Administration console and create and configure a new JMS connection factory and a new jms destination (queue). Now we should create a new resource of type “alert destination” within our Oracle Service Bus project. The new “alert destination” resource should be configured using the newly created connection factory jms and jms destination. Finally, in order to withdraw the message alert enqueued in our JMS destination and send it to our coherence node, we just need to create a new business service and proxy service within our Oracle Service Bus project.Our business service is responsible for sending a message to our REST service Coherence using as a method action: PUT Finally our proxy service have to collect all messages enqueued on the destination, execute an xquery transformation on those messages in order to translate them into valid XML / alert objects useful to be sent to our coherence service, through the newly created business service. The message flow pipeline containing the xquery transformation: Incredibly, we just did a basic first integration between the native alerting system of Oracle Service Bus and our centralized alerting system by simply configuring our coherence node without developing anything.It's time to test it out. To do this I create a proxy service able to generate an alert using our "alert destination", whenever the proxy is invoked. After some invocation to our proxy that generates fake alerts, we could open an Internet browser and type the URL http://localhost: 8080/alerts/ so we could see what has been inserted within the coherence node. 8) We are ready for the final step. We would create a new message flow, that can be used to search and display the results in standard mode. To do this I choosen the standard representation of RSS, to display a formatted result on a huge variety of devices such as readers for the iPhone and Android. The inquiry may be defined already at the time of the request able to return only feed / items related to our needs. To do this we need to create a new business service, a new proxy service, and finally a new XQuery Transformation to take care of translating the collection of alerts that will be return from our coherence node in a nicely formatted RSS standard document.So we start right from this resource (xquery), which has the task of transforming a collection of alerts / xml returned from the node coherence in a type well-formatted feed RSS 2.0 our new business service that will search the alerts on our coherence node using the Rest API. And finally, our last resource, the proxy service that will be exposed as an RSS / feeds to various mobile devices and traditional web readers, in which we will intercept any search query, and transform the result returned by the business service in an RSS feed 2.0. The message flow with the transformation phase (Alert TO Feed Items): Finally some little tricks to follow during the routing to the business service, - check for any queries present in the url to require a subset of alerts - the http header "Accept" to help get an answer XML instead of JSON: In our little demo we also static added some coherence parameters to the request:sort=time:desc;start=0;count=100I would like to get from Coherence that the results will be sorted by date, and starting from 1 up to a maximum of 100.Done!!Just incredible, our centralized alerting system is ready. Inheriting all the qualities and capabilities of the two products involved Oracle Coherence & Oracle Service Bus: - RASP (Reliability, Availability, Scalability, Performance)Now try to use your mobile device, or a normal Internet browser by accessing the RSS just published: Some urls you may test: Search for the last 100 alerts : http://localhost:7001/alarmsSearch for alerts that do not have time set to null (time is not null):http://localhost:7001/alarms?q=time+is+not+nullSearch for alerts that the system property is “Web Browser” (system = ‘Web Browser’):http://localhost:7001/alarms?q=system+%3D+%27Web+Browser%27Search for alerts that the system property is “Web Browser” and the severity property is “Fatal” and the title property contain the word “Javascript” (system = ‘Web Broser’ and severity = ‘Fatal’ and title like ‘%Javascript%’)http://localhost:8080/alerts?q=system+%3D+%27Web+Browser%27+AND+severity+%3D+%27Fatal%27+AND+title+LIKE+%27%25Javascript%25%27 To compose more complex queries about your need I would suggest you to read the chapter in the coherence documentation inherent the Cohl language (Coherence Query Language) http://download.oracle.com/docs/cd/E24290_01/coh.371/e22837/api_cq.htm . Some useful links: - Oracle Coherence REST API Documentation http://download.oracle.com/docs/cd/E24290_01/coh.371/e22839/rest_intro.htm - Oracle Service Bus Documentation http://download.oracle.com/docs/cd/E21764_01/soa.htm#osb - REST explanation from Wikipedia http://en.wikipedia.org/wiki/Representational_state_transfer At this URL could be downloaded the whole materials of this demo http://blogs.oracle.com/slc/resource/cosb/coh-sb-demo.zip Author: Nino Guarnacci.

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PASS Summit Feedback

- by Rob Farley

PASS Feedback came in last week. I also saw my dentist for some fillings... At the PASS Summit this year, I delivered a couple of regular sessions and a Lightning Talk. People told me they enjoyed it, but when the rankings came out, they showed that I didn’t score particularly well. Brent Ozar was keen to discuss it with me. Brent: PASS speaker feedback is out. You did two sessions and a Lightning Talk. How did you go? Rob: Not so well actually, thanks for asking. Brent: Ha! Sorry. Of course you know that's why I wanted to discuss this with you. I was in one of your sessions at SQLBits in the UK a month before PASS, and I thought you rocked. You've got a really good and distinctive delivery style. Then I noticed your talks were ranked in the bottom quarter of the Summit ratings and wanted to discuss it. Rob: Yeah, I know. You did ask me if we could do this... I should explain – my presentation style is not the stereotypical IT conference one. I throw in jokes, and try to engage the audience thoroughly. I find many talks amazingly dry, and I guess I try to buck that trend. I also run training courses, and find that I get a lot of feedback from people thanking me for keeping things interesting. That said, I also get feedback criticising me for my style, and that’s basically what’s happened here. For the rest of this discussion, let’s focus on my talk about the Incredible Shrinking Execution Plan, which I considered to be my main talk. Brent: I thought that session title was the very best one at the entire Summit, and I had it on my recommended sessions list. In four words, you managed to sum up the topic and your sense of humor. I read that and immediately thought, "People need to be in this session," and then it didn't score well. Tell me about your scores. Rob: The questions on the feedback form covered the usefulness of the information, the speaker’s presentation skills, their knowledge of the subject, how well the session was described, the amount of time allocated, and the quality of the presentation materials. Brent: Presentation materials? But you don’t do slides. Did they rate your thong? Rob: No-one saw my flip-flops in this talk, Brent. I created a script in Management Studio, and published that afterwards, but I think people will have scored that question based on the lack of slides. I wasn’t expecting to do particularly well on that one. That was the only section that didn’t have 5/5 as the most popular score. Brent: See, that sucks, because cookbook-style scripts are often some of my favorites. Adam Machanic's Service Broker workbench series helped me immensely when I was prepping for the MCM. As an attendee, I'd rather have a commented script than a slide deck. So how did you rank so low? Rob: When I look at the scores that you got (based on your blog post), you got very few scores below 3 – people that felt strong enough about your talk to post a negative score. In my scores, between 5% and 10% were below 3 (except on the question about whether I knew my stuff – I guess I came as knowledgeable). Brent: Wow – so quite a few people really didn’t like your talk then? Rob: Yeah. Mind you, based on the comments, some people really loved it. I’d like to think that there would be a certain portion of the room who may have rated the talk as one of the best of the conference. Some of my comments included “amazing!”, “Best presentation so far!”, “Wow, best session yet”, “fantastic” and “Outstanding!”. I think lots of talks can be “Great”, but not so many talks can be “Outstanding” without the word losing its meaning. One wrote “Pretty amazing presentation, considering it was completely extemporaneous.” Brent: Extemporaneous, eh? Rob: Yeah. I guess they don’t realise how much preparation goes into coming across as unprepared. In many ways it’s much easier to give a written speech than to deliver a presentation without slides as a prompt. Brent: That delivery style, the really relaxed, casual, college-professor approach was one of the things I really liked about your presentation at SQLbits. As somebody who presents a lot, I "get" it - I know how hard it is to come off as relaxed and comfortable with your own material. It's like improv done by jazz players and comedians - if you've never tried it, you don't realize how hard it is. People also don't realize how hard it is to make a tough subject fun. Rob: Yeah well... There will be people writing comments on this post that say I wasn't trying to make the subject fun, and that I was making it all about me. Sometimes the style works, sometimes it doesn't. Most of the comments mentioned the fact that I tell jokes, some in a nice way, but some not so much (and it wasn't just a PASS thing - that's the mix of feedback I generally get). One comment at PASS was: “great stand up comedian - not what I'm looking for at pass”, and there were certainly a few that said “too many jokes”. I’m not trying to do stand-up – jokes are my way of engaging with the audience while I demonstrate some of the amazing things that the Query Optimizer can do if you write your queries the right way. Some people didn’t think it was technical enough, but I’ve also had some people tell me that the concepts I’m explaining are deep and profound. Brent: To me, that's a hallmark of a great explanation - when someone says, "But of course it has to work that way - how could it work any other way? It seems so simple and logical." Well, sure it does when it's explained correctly, but now pick up any number of thick SQL Server books and try to understand the Redundant Joins concept. I guarantee it'll take more than 45 minutes. Rob: Some people in my audiences realise that, but definitely not everyone. There's only so much you can tell someone that something is profound. Generally it's something that they either have an epiphany on or not. I like to lull my audience into knowing what's going on, and do something that surprises them. Gain their trust, build a rapport, and then show them the deeper truth of what just happened. Brent: So you've learned your lesson about presentation scores, right? From here on out, you're going to be dry, humorless, and all your presentations will consist of you reading bullet points off the screen. Rob: No Brent, I’m not. I'm also not going to suggest that most presentations at PASS are like that. No-one tries to present like that. There's a big space to occupy between what "dry and humourless" and me. My difference is to focus on the relationship I have with the crowd, rather than focussing on delivering the perfect session. I want to see people smiling and know they're relaxed. I think most presenters focus on the material, which is completely reasonable and safe. I remember once hearing someone talking about product creation. They talked about mediocrity. They said that one of the worst things that people can ever say about your product is that it’s “good”. What you want is for 10% of the world to love it enough to want to buy it. If 10% the world gave me a dollar, I’d have more money than I could ever use (assuming it wasn’t the SAME dollar they were giving me I guess). Brent: It's the Raving Fans theory. It's better to have a small number of raving customers than a large number of almost-but-not-really customers who don't care that much about your product or service. I know exactly how you feel - when I got survey feedback from my Quest video presentation when I was dressed up in a Richard Simmons costume, some of the attendees said I was unprofessional and distracting. Some of the attendees couldn't get enough and Photoshopped all kinds of stuff into the screen captures. On a whole, I probably didn't score that well, and I'm fine with that. It sucks to look at the scores though - do those lower scores bother you? Rob: Of course they do. It hurts deeply. I open myself up and give presentations in a very personal way. All presenters do that, and we all feel the pain of negative feedback. I hate coming 146th & 162nd out of 185, but have to acknowledge that many sessions did worse still. Plus, once I feel the wounds have healed, I’ll be able to remember that there are people in the world that rave about my presentation style, and figure that people will hopefully talk about me. One day maybe those people that don’t like my presentation style will stay away and I might be able to score better. You don’t pay to hear country music if you prefer western... Lots of people find chili too spicy, but it’s still a popular food. Brent: But don’t you want to appeal to everyone? Rob: I do, but I don’t want to be lukewarm as in Revelation 3:16. I’d rather disgust and be discussed. Well, maybe not ‘disgust’, but I don’t want to conform. Conformity just isn’t the same any more. I’m not sure I’ve ever been one to do that. I try not to offend, but definitely like to be different. Brent: Count me among your raving fans, sir. Where can we see you next? Rob: Considering I live in Adelaide in Australia, I’m not about to appear at anyone’s local SQL Saturday. I’m still trying to plan which events I’ll get to in 2011. I’ve submitted abstracts for TechEd North America, but won’t hold my breath. I’m also considering the SQLBits conferences in the UK in April, PASS in October, and I’m sure I’ll do some LiveMeeting presentations for user groups. Online, people download some of my recent SQLBits presentations at http://bit.ly/RFSarg and http://bit.ly/Simplification though. And they can download a 5-minute MP3 of my Lightning Talk at http://www.lobsterpot.com.au/files/Collation.mp3, in which I try to explain the idea behind collation, using thongs as an example. Brent: I was in the audience for http://bit.ly/RFSarg. That was a great presentation. Rob: Thanks, Brent. Now where’s my dollar?

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