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  • Figuring Out Memory Leaks without Clang

    - by RoLYroLLs
    I'm trying to see if I can find some leaks myself in Apple's TopSongs app. Can someone help me out in at least one and how to identify what is in the Leaks reports and how I can get an idea on finding them? ie: I got one like this: # Category Event Type Timestamp Address Size Responsible Library Responsible Caller 0 GeneralBlock-448 Malloc 00:02.185 0x3f41220 448 libxml2.2.dylib xmlNewParserCtxt From what I can tell, the method xmlNewParserCtxt is the problem, and it's not releasing an object, hence Malloc. The responsible library tells me it's the libxml2.2.dylib library with the problem, which I can't edit. Am I heading in the right direction? If so, half the leaks are in that library and well, i can't edit that.

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  • creating Linq to sqlite dbml from DbLinq source code

    - by Veer
    Hi All, I tried to create linq-to-sqlite dbml using DbLinq but in vain. Each time I get different type of errors. May be I'm somewhere wrong. Can anyone tell me the step by step procedure to create the dbml file from the Dblinq source code. Edit: Steps I Followed: I downloaded the source file from this link. Edited the "run_sqliteMetal.bat" file in \\DbLinq-0.19\src\DbMetal folder as 'DbMetal.exe -database:myDb.db3 -namespace:myNS -code:myCode.cs' -dbml:myDbml.dbml Tried to run the DbMetal project file to produce the executable but there was a runtime error since Options object in Parameters.cs was null. Hence downloaded the readymade exe file from this location Copied it into the \DbLinq-0.19\src\DbMetal folder Executed the "run_sqliteMetal.bat" file I got a blank screen and Windows Error Msg "DbLinq has stopped Working" Any help? Thanks in advance, Veer

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  • HTTP Status 403 - Access to the requested resource has been denied

    - by Stardust
    I want to enable form based authentication by using database as realm but I'm always getting that message whenever I try to authenticate as Tomcat manager in Tomcat 6. I have already created a table user_name and user_roles and mapped the username(blue) to admin and manager as role in user_roles table in mysql, but still I'm unable to authenticate and enable form based authentication. I've alreay recreated realm tag in server.xml file: <Realm className="org.apache.catalina.realm.JDBCRealm" debug="99" driverName="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/mail" connectionName="root" userTable="users" userNameCol="user_name" userCredCol="user_pass" userRoleTable="user_roles" roleNameCol="role_name" /> Could anyone please tell me what's wrong I'm doing?

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  • GUI to include a .prop file in a VS 2010 project?

    - by jwfearn
    Visual Studio 2010 has no longer uses .vsprops files and instead uses .props files. To include a .vsprops file in a Visual Studio 2008 project, one could right-click the project icon in the Solution Explorer panel, choose Properties, go to the Configuration Properties | General section, and modify the Inherited Project Property Sheets property to contain a list of .vsprops paths. One could also modify the Visual Studio 2008 project file directly. Is there a way in the Visual Studio 2010 GUI to include .props files to a project? The Inherited Project Property Sheets property seems to have been removed. If manual editing of the project file is the only way to include .props files, where can one find documentation on doing it? I'm not talking about adding a .props file to the list of files in the project, I mean how do I tell the project to use a .props file.

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  • how to handle iframes/frames dom in the iphone uiwebview

    - by user217428
    in (void) webViewDidFinishLoad: (UIWebView*)webView I inject some javascript to handle the iframes. e.g. stringByEvaluatingJavaScriptFromString: @"try { var document = window.document.getElementsByTagName('iframe')[0].contentWindow.document.getElementsByTagName('frame'); } catch (e) { alert (e.message); }" It tells me the iframes document is undefined. Actually I have tried to print all the properties of contentWindow of iframe, but it's totally empty. I know the webViewDidFinishLoad may be called several times for each frame load. But I can never get the iframe document. I thought there should be at least once all the iframes are ready. Could someone please tell me how to get the iframe document to process the dom in the uiwebview? Thanks

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  • WiX - create a bootstrap that passes arguments to the msi

    - by Dror Helper
    I need to create a bootstrap for my WiX project I've tried using setupbld.exe but it will only allow me to create an executable that will show my UI or one that will behave as a silent installer but not both. I need to be able to run the resulting executable with argument that will tell it wether or not to show the UI during installation. I've found this post by John Robbins that explains how to re-build the setup.exe stub used in the creation of the bootstrap but I was hoping there is a simpler way to do what I need. Does anyone know of a way to create a bootstrap that I use to run either as a simple (with UI) install or as a silent install.

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  • Using WPFPerf to profile a WPF 4.0 application doesn't show me any information

    - by Adrian
    I am trying to use WPFPerf to profile a WPF 4.0 application (I have the latest WPFPerf that should work on WPF 4.0 aps). I start the tool Visual Profiler from WPFPerf, I start my aplication, but after that nothing happens and the element tree from the Visual Profiler is empty. No other error message is shown. Can anyone tell me what am I not doint right? As an additional information, when I try to analize my .exe assembly or any other assembly from my application, I get a BadFormatException saying that the assembly was build with a newer version of .NET. From the download page http://go.microsoft.com/fwlink/?LinkID=191420 I see that this version of WPFPerf should be ok for my app

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  • Embedding an offline Dashcode application in a UIWebView in an iPhone application

    - by Nimrod
    In order words, can anyone tell me the basics of how to create a "hybrid" iPhone application? I want to load the web content (the Dashcode app itself) from the native application's application bundle. I've gotten this to partially work, but some content won't display and it otherwise seems like Dashcode is assuming a certain Safari environment or something that I don't seem to have in my UIWebView. Can anyone provide a link to some sample code that embeds a Dashcode project into a cocoa touch Xcode project? (I did search around Google for a bit trying to find something and I failed to come up with anything worthwhile, except for some books that I might eventually buy if the approach seems worthwhile.)

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  • Detect Click into Iframe using JavaScript

    - by Russ Bradberry
    I understand that it is not possible to tell what the user is doing inside an iframe if it is cross domain. What I would like to do is track if the user clicked at all in the iframe. I imagine a scenario where there is an invisible div on top of the iframe and the the div will just then pass the click event to the iframe. Is something like this possible? If it is, then how would I go about it? The iframes are ads, so I have no control over the tags that are used.

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  • jQuery animate mouseover/mouseout keep drop menu visible

    - by Ce.
    I'm trying to make a basic drop down menu with animate and am running into the issue where I can't seem to figure out how to keep the dropdown part open until the mouse leaves. Is there an easy way to tell this to stay open? I know what I have is completely wrong regarding the .clickme mouseout function since it will unload the menu accordingly. If anyone can help in this specific instance, I would be super grateful. PREVIEW HERE http://cu3ed.com/ddmenu/ or below: $(document).ready(function() { $('.clickme').mouseover(function() { $('#slidebox').animate({ top: '+=160' }, 200, 'easeOutQuad'); }); $('.clickme').mouseout(function(){ $('#slidebox').animate({ top: '-=160' }, 200, 'easeOutQuad') }); }); I would like to keep this as simple and clean as possible. I know the CSS is all crazy but it's totally preliminary. THANKS!!!

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  • Disable browser 'Save Password' functionality

    - by mattsmith321
    One of the joys of working for a government healthcare agency is having to deal with all of the paranoia around dealing with PHI (Protected Health Information). Don't get me wrong, I'm all for doing everything possible to protect people's personal information (health, financial, surfing habits, etc.), but sometimes people get a little too jumpy. Case in point: One of our state customers recently found out that the browser provides the handy feature to save your password. We all know that it has been there for a while and is completely optional and is up to the end user to decide whether or not it is a smart decision to use or not. However, there is a bit of an uproar at the moment and we are being demanded to find a way to disable that functionality for our site. Question: Is there a way for a site to tell the browser not to offer to remember passwords? I've been around web development a long time but don't know that I have come across that before. Any help is appreciated. Thanks, Matt

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  • Jquery JQGrid breaks when contentType=application/json?

    - by JK
    I've had to use $.ajaxSetup() to globally change the contentType to application/json $.ajaxSetup({ contentType: "application/json; charset=utf-8" }); (See this question for why I had to use application/json http://stackoverflow.com/questions/2792603/aspnet-mvc-why-is-modelstate-isvalid-false-the-x-field-is-required-when-that) But this breaks the jquery jqrid with this error: Invalid JSON primitive: _search The POST data it is trying to send is: _search=false&nd=1274042681880&rows=20&page=1&sidx=&sord=asc Which of is not in json format, so of course it fails. Is there anyway to tell jqrid what contenttype to use? I have searched on the jqrid wiki, but doesn't have much documentation about anything really. http://www.trirand.com/jqgridwiki/doku.php?do=search&id=contenttype&fulltext=Search

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  • RDLC: How to print multiple tables in one report

    - by Eduardo Molteni
    I'm generating the RDLC XML schema and showing the report in the ReportViewer control. No problems there. Now, I want a report with 2 tables, with 2 differents dataset. Something like this gets generated: <Body> <ReportItems> <Table Name="Table1"> .... </Table> <Table Name="Table2"> .... </Table> </ReportItems> </Body> But, when printed, both tables start from the top, printing one table over the other (not nice) Is there a way to tell that Table2 should start after Table1? Update: I've tried with List with a fake DataSource, but it does not work.

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  • What makes a good software developer? [closed]

    - by David Johnstone
    Previously there have been questions on what makes a good team lead and what makes a good programming team, but I can't find any questions on what makes a good programmer. I believe the answer to this question is especially important in the context of hiring. Hiring the best people you can afford only works when you are able to identify who the best people are. Being able to consistently identify the best people is only possible when you know what makes the best people the best people. The easy answer is "smart and gets things done" (see "Done, and Gets Things Smart" for an interesting response). But surely there is more to being a good software developer than this aphorism. So, what makes a good software developer a good software developer? (Note: For the purposes of this question, I'm not interested in how to actually tell if somebody is a good software developer.)

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  • Using VLOOKUP in Excel

    - by Mark Virtue
    VLOOKUP is one of Excel’s most useful functions, and it’s also one of the least understood.  In this article, we demystify VLOOKUP by way of a real-life example.  We’ll create a usable Invoice Template for a fictitious company. So what is VLOOKUP?  Well, of course it’s an Excel function.  This article will assume that the reader already has a passing understanding of Excel functions, and can use basic functions such as SUM, AVERAGE, and TODAY.  In its most common usage, VLOOKUP is a database function, meaning that it works with database tables – or more simply, lists of things in an Excel worksheet.  What sort of things?   Well, any sort of thing.  You may have a worksheet that contains a list of employees, or products, or customers, or CDs in your CD collection, or stars in the night sky.  It doesn’t really matter. Here’s an example of a list, or database.  In this case it’s a list of products that our fictitious company sells: Usually lists like this have some sort of unique identifier for each item in the list.  In this case, the unique identifier is in the “Item Code” column.  Note:  For the VLOOKUP function to work with a database/list, that list must have a column containing the unique identifier (or “key”, or “ID”), and that column must be the first column in the table.  Our sample database above satisfies this criterion. The hardest part of using VLOOKUP is understanding exactly what it’s for.  So let’s see if we can get that clear first: VLOOKUP retrieves information from a database/list based on a supplied instance of the unique identifier. Put another way, if you put the VLOOKUP function into a cell and pass it one of the unique identifiers from your database, it will return you one of the pieces of information associated with that unique identifier.  In the example above, you would pass VLOOKUP an item code, and it would return to you either the corresponding item’s description, its price, or its availability (its “In stock” quantity).  Which of these pieces of information will it pass you back?  Well, you get to decide this when you’re creating the formula. If all you need is one piece of information from the database, it would be a lot of trouble to go to to construct a formula with a VLOOKUP function in it.  Typically you would use this sort of functionality in a reusable spreadsheet, such as a template.  Each time someone enters a valid item code, the system would retrieve all the necessary information about the corresponding item. Let’s create an example of this:  An Invoice Template that we can reuse over and over in our fictitious company. First we start Excel… …and we create ourselves a blank invoice: This is how it’s going to work:  The person using the invoice template will fill in a series of item codes in column “A”, and the system will retrieve each item’s description and price, which will be used to calculate the line total for each item (assuming we enter a valid quantity). For the purposes of keeping this example simple, we will locate the product database on a separate sheet in the same workbook: In reality, it’s more likely that the product database would be located in a separate workbook.  It makes little difference to the VLOOKUP function, which doesn’t really care if the database is located on the same sheet, a different sheet, or a completely different workbook. In order to test the VLOOKUP formula we’re about to write, we first enter a valid item code into cell A11: Next, we move the active cell to the cell in which we want information retrieved from the database by VLOOKUP to be stored.  Interestingly, this is the step that most people get wrong.  To explain further:  We are about to create a VLOOKUP formula that will retrieve the description that corresponds to the item code in cell A11.  Where do we want this description put when we get it?  In cell B11, of course.  So that’s where we write the VLOOKUP formula – in cell B11. Select cell B11: We need to locate the list of all available functions that Excel has to offer, so that we can choose VLOOKUP and get some assistance in completing the formula.  This is found by first clicking the Formulas tab, and then clicking Insert Function:   A box appears that allows us to select any of the functions available in Excel.  To find the one we’re looking for, we could type a search term like “lookup” (because the function we’re interested in is a lookup function).  The system would return us a list of all lookup-related functions in Excel.  VLOOKUP is the second one in the list.  Select it an click OK… The Function Arguments box appears, prompting us for all the arguments (or parameters) needed in order to complete the VLOOKUP function.  You can think of this box as the function is asking us the following questions: What unique identifier are you looking up in the database? Where is the database? Which piece of information from the database, associated with the unique identifier, do you wish to have retrieved for you? The first three arguments are shown in bold, indicating that they are mandatory arguments (the VLOOKUP function is incomplete without them and will not return a valid value).  The fourth argument is not bold, meaning that it’s optional:   We will complete the arguments in order, top to bottom. The first argument we need to complete is the Lookup_value argument.  The function needs us to tell it where to find the unique identifier (the item code in this case) that it should be retuning the description of.  We must select the item code we entered earlier (in A11). Click on the selector icon to the right of the first argument: Then click once on the cell containing the item code (A11), and press Enter: The value of “A11” is inserted into the first argument. Now we need to enter a value for the Table_array argument.  In other words, we need to tell VLOOKUP where to find the database/list.  Click on the selector icon next to the second argument: Now locate the database/list and select the entire list – not including the header line.  The database is located on a separate worksheet, so we first click on that worksheet tab: Next we select the entire database, not including the header line: …and press Enter.  The range of cells that represents the database (in this case “’Product Database’!A2:D7”) is entered automatically for us into the second argument. Now we need to enter the third argument, Col_index_num.  We use this argument to specify to VLOOKUP which piece of information from the database, associate with our item code in A11, we wish to have returned to us.  In this particular example, we wish to have the item’s description returned to us.  If you look on the database worksheet, you’ll notice that the “Description” column is the second column in the database.  This means that we must enter a value of “2” into the Col_index_num box: It is important to note that that we are not entering a “2” here because the “Description” column is in the B column on that worksheet.  If the database happened to start in column K of the worksheet, we would still enter a “2” in this field. Finally, we need to decide whether to enter a value into the final VLOOKUP argument, Range_lookup.  This argument requires either a true or false value, or it should be left blank.  When using VLOOKUP with databases (as is true 90% of the time), then the way to decide what to put in this argument can be thought of as follows: If the first column of the database (the column that contains the unique identifiers) is sorted alphabetically/numerically in ascending order, then it’s possible to enter a value of true into this argument, or leave it blank. If the first column of the database is not sorted, or it’s sorted in descending order, then you must enter a value of false into this argument As the first column of our database is not sorted, we enter false into this argument: That’s it!  We’ve entered all the information required for VLOOKUP to return the value we need.  Click the OK button and notice that the description corresponding to item code “R99245” has been correctly entered into cell B11: The formula that was created for us looks like this: If we enter a different item code into cell A11, we will begin to see the power of the VLOOKUP function:  The description cell changes to match the new item code: We can perform a similar set of steps to get the item’s price returned into cell E11.  Note that the new formula must be created in cell E11.  The result will look like this: …and the formula will look like this: Note that the only difference between the two formulae is the third argument (Col_index_num) has changed from a “2” to a “3” (because we want data retrieved from the 3rd column in the database). If we decided to buy 2 of these items, we would enter a “2” into cell D11.  We would then enter a simple formula into cell F11 to get the line total: =D11*E11 …which looks like this… Completing the Invoice Template We’ve learned a lot about VLOOKUP so far.  In fact, we’ve learned all we’re going to learn in this article.  It’s important to note that VLOOKUP can be used in other circumstances besides databases.  This is less common, and may be covered in future How-To Geek articles. Our invoice template is not yet complete.  In order to complete it, we would do the following: We would remove the sample item code from cell A11 and the “2” from cell D11.  This will cause our newly created VLOOKUP formulae to display error messages: We can remedy this by judicious use of Excel’s IF() and ISBLANK() functions.  We change our formula from this…       =VLOOKUP(A11,’Product Database’!A2:D7,2,FALSE) …to this…       =IF(ISBLANK(A11),”",VLOOKUP(A11,’Product Database’!A2:D7,2,FALSE)) We would copy the formulas in cells B11, E11 and F11 down to the remainder of the item rows of the invoice.  Note that if we do this, the resulting formulas will no longer correctly refer to the database table.  We could fix this by changing the cell references for the database to absolute cell references.  Alternatively – and even better – we could create a range name for the entire product database (such as “Products”), and use this range name instead of the cell references.  The formula would change from this…       =IF(ISBLANK(A11),”",VLOOKUP(A11,’Product Database’!A2:D7,2,FALSE)) …to this…       =IF(ISBLANK(A11),”",VLOOKUP(A11,Products,2,FALSE)) …and then copy the formulas down to the rest of the invoice item rows. We would probably “lock” the cells that contain our formulae (or rather unlock the other cells), and then protect the worksheet, in order to ensure that our carefully constructed formulae are not accidentally overwritten when someone comes to fill in the invoice. We would save the file as a template, so that it could be reused by everyone in our company If we were feeling really clever, we would create a database of all our customers in another worksheet, and then use the customer ID entered in cell F5 to automatically fill in the customer’s name and address in cells B6, B7 and B8. If you would like to practice with VLOOKUP, or simply see our resulting Invoice Template, it can be downloaded from here. Similar Articles Productive Geek Tips Make Excel 2007 Print Gridlines In Workbook FileMake Excel 2007 Always Save in Excel 2003 FormatConvert Older Excel Documents to Excel 2007 FormatImport Microsoft Access Data Into ExcelChange the Default Font in Excel 2007 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Classic Cinema Online offers 100’s of OnDemand Movies OutSync will Sync Photos of your Friends on Facebook and Outlook Windows 7 Easter Theme YoWindoW, a real time weather screensaver Optimize your computer the Microsoft way Stormpulse provides slick, real time weather data

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  • Read half precision float (float16 IEEE 754r) binary data in matlab

    - by Michael
    you have been a great help last time, i hope you can give me some advise this time, too. I read a binary file into matlab with bit16 (format = bitn) and i get a string of ones and zeros. bin = '1 00011 1111111111' (16 bits: 1. sign, 2-6. exponent, 7-16. mantissa) According to ftp://www.fox-toolkit.org/pub/fasthalffloatconversion.pdf it can be 'converted' like out = (-1)^bin(1) * 2^(bin(2:6)-15) * 1.bin(7:16) [are exponent and mantissa still binary?] Can someone help me out and tell me how to deal with the 'eeeee' and '1.mmmmmmmmmm' as mentioned in the pdf, please. Thanks a lot! Michael

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  • Load and Web Performance Testing using Visual Studio Ultimate 2010-Part 3

    - by Tarun Arora
    Welcome back once again, in Part 1 of Load and Web Performance Testing using Visual Studio 2010 I talked about why Performance Testing the application is important, the test tools available in Visual Studio Ultimate 2010 and various test rig topologies, in Part 2 of Load and Web Performance Testing using Visual Studio 2010 I discussed the details of web performance & load tests as well as why it’s important to follow a goal based pattern while performance testing your application. In part 3 I’ll be discussing Test Result Analysis, Test Result Drill through, Test Report Generation, Test Run Comparison, Asp.net Profiler and some closing thoughts. Test Results – I see some creepy worms! In Part 2 we put together a web performance test and a load test, lets run the test to see load test to see how the Web site responds to the load simulation. While the load test is running you will be able to see close to real time analysis in the Load Test Analyser window. You can use the Load Test Analyser to conduct load test analysis in three ways: Monitor a running load test - A condensed set of the performance counter data is maintained in memory. To prevent the results memory requirements from growing unbounded, up to 200 samples for each performance counter are maintained. This includes 100 evenly spaced samples that span the current elapsed time of the run and the most recent 100 samples.         After the load test run is completed - The test controller spools all collected performance counter data to a database while the test is running. Additional data, such as timing details and error details, is loaded into the database when the test completes. The performance data for a completed test is loaded from the database and analysed by the Load Test Analyser. Below you can see a screen shot of the summary view, this provides key results in a format that is compact and easy to read. You can also print the load test summary, this is generated after the test has completed or been stopped.         Analyse the load test results of a previously run load test – We’ll see this in the section where i discuss comparison between two test runs. The performance counters can be plotted on the graphs. You also have the option to highlight a selected part of the test and view details, drill down to the user activity chart where you can hover over to see more details of the test run.   Generate Report => Test Run Comparisons The level of reports you can generate using the Load Test Analyser is astonishing. You have the option to create excel reports and conduct side by side analysis of two test results or to track trend analysis. The tools also allows you to export the graph data either to MS Excel or to a CSV file. You can view the ASP.NET profiler report to conduct further analysis as well. View Data and Diagnostic Attachments opens the Choose Diagnostic Data Adapter Attachment dialog box to select an adapter to analyse the result type. For example, you can select an IntelliTrace adapter, click OK and open the IntelliTrace summary for the test agent that was used in the load test.   Compare results This creates a set of reports that compares the data from two load test results using tables and bar charts. I have taken these screen shots from the MSDN documentation, I would highly recommend exploring the wealth of knowledge available on MSDN. Leaving Thoughts While load testing the application with an excessive load for a longer duration of time, i managed to bring the IIS to its knees by piling up a huge queue of requests waiting to be processed. This clearly means that the IIS had run out of threads as all the threads were busy processing existing request, one easy way of fixing this is by increasing the default number of allocated threads, but this might escalate the problem. The better suggestion is to try and drill down to the actual root cause of the problem. When ever the garbage collection runs it stops processing any pages so all requests that come in during that period are queued up, but realistically the garbage collection completes in fraction of a a second. To understand this better lets look at the .net heap, it is divided into large heap and small heap, anything greater than 85kB in size will be allocated to the Large object heap, the Large object heap is non compacting and remember large objects are expensive to move around, so if you are allocating something in the large object heap, make sure that you really need it! The small object heap on the other hand is divided into generations, so all objects that are supposed to be short-lived are suppose to live in Gen-0 and the long living objects eventually move to Gen-2 as garbage collection goes through.  As you can see in the picture below all < 85 KB size objects are first assigned to Gen-0, when Gen-0 fills up and a new object comes in and finds Gen-0 full, the garbage collection process is started, the process checks for all the dead objects and assigns them as the valid candidate for deletion to free up memory and promotes all the remaining objects in Gen-0 to Gen-1. So in the future when ever you clean up Gen-1 you have to clean up Gen-0 as well. When you fill up Gen – 0 again, all of Gen – 1 dead objects are drenched and rest are moved to Gen-2 and Gen-0 objects are moved to Gen-1 to free up Gen-0, but by this time your Garbage collection process has started to take much more time than it usually takes. Now as I mentioned earlier when garbage collection is being run all page requests that come in during that period are queued up. Does this explain why possibly page requests are getting queued up, apart from this it could also be the case that you are waiting for a long running database process to complete.      Lets explore the heap a bit more… What is really a case of crisis is when the objects are living long enough to make it to Gen-2 and then dying, this is definitely a high cost operation. But sometimes you need objects in memory, for example when you cache data you hold on to the objects because you need to use them right across the user session, which is acceptable. But if you wanted to see what extreme caching can do to your server then write a simple application that chucks in a lot of data in cache, run a load test over it for about 10-15 minutes, forcing a lot of data in memory causing the heap to run out of memory. If you get to such a state where you start running out of memory the IIS as a mode of recovery restarts the worker process. It is great way to free up all your memory in the heap but this would clear the cache. The problem with this is if the customer had 10 items in their shopping basket and that data was stored in the application cache, the user basket will now be empty forcing them either to get frustrated and go to a competitor website or if the customer is really patient, give it another try! How can you address this, well two ways of addressing this; 1. Workaround – A x86 bit processor only allows a maximum of 4GB of RAM, this means the machine effectively has around 3.4 GB of RAM available, the OS needs about 1.5 GB of RAM to run efficiently, the IIS and .net framework also need their share of memory, leaving you a heap of around 800 MB to play with. Because Team builds by default build your application in ‘Compile as any mode’ it means the application is build such that it will run in x86 bit mode if run on a x86 bit processor and run in a x64 bit mode if run on a x64 but processor. The problem with this is not all applications are really x64 bit compatible specially if you are using com objects or external libraries. So, as a quick win if you compiled your application in x86 bit mode by changing the compile as any selection to compile as x86 in the team build, you will be able to run your application on a x64 bit machine in x86 bit mode (WOW – By running Windows on Windows) and what that means is, you could use 8GB+ worth of RAM, if you take away everything else your application will roughly get a heap size of at least 4 GB to play with, which is immense. If you need a heap size of more than 4 GB you have either build a software for NASA or there is something fundamentally wrong in your application. 2. Solution – Now that you have put a workaround in place the IIS will not restart the worker process that regularly, which means you can take a breather and start working to get to the root cause of this memory leak. But this begs a question “How do I Identify possible memory leaks in my application?” Well i won’t say that there is one single tool that can tell you where the memory leak is, but trust me, ‘Performance Profiling’ is a great start point, it definitely gets you started in the right direction, let’s have a look at how. Performance Wizard - Start the Performance Wizard and select Instrumentation, this lets you measure function call counts and timings. Before running the performance session right click the performance session settings and chose properties from the context menu to bring up the Performance session properties page and as shown in the screen shot below, check the check boxes in the group ‘.NET memory profiling collection’ namely ‘Collect .NET object allocation information’ and ‘Also collect the .NET Object lifetime information’.    Now if you fire off the profiling session on your pages you will notice that the results allows you to view ‘Object Lifetime’ which shows you the number of objects that made it to Gen-0, Gen-1, Gen-2, Large heap, etc. Another great feature about the profile is that if your application has > 5% cases where objects die right after making to the Gen-2 storage a threshold alert is generated to alert you. Since you have the option to also view the most expensive methods and by capturing the IntelliTrace data you can drill in to narrow down to the line of code that is the root cause of the problem. Well now that we have seen how crucial memory management is and how easy Visual Studio Ultimate 2010 makes it for us to identify and reproduce the problem with the best of breed tools in the product. Caching One of the main ways to improve performance is Caching. Which basically means you tell the web server that instead of going to the database for each request you keep the data in the webserver and when the user asks for it you serve it from the webserver itself. BUT that can have consequences! Let’s look at some code, trust me caching code is not very intuitive, I define a cache key for almost all searches made through the common search page and cache the results. The approach works fine, first time i get the data from the database and second time data is served from the cache, significant performance improvement, EXCEPT when two users try to do the same operation and run into each other. But it is easy to handle this by adding the lock as you can see in the snippet below. So, as long as a user comes in and finds that the cache is empty, the user locks and starts to get the cache no more concurrency issues. But lets say you are processing 10 requests per second, by the time i have locked the operation to get the results from the database, 9 other users came in and found that the cache key is null so after i have come out and populated the cache they will still go in to get the results again. The application will still be faster because the next set of 10 users and so on would continue to get data from the cache. BUT if we added another null check after locking to build the cache and before actual call to the db then the 9 users who follow me would not make the extra trip to the database at all and that would really increase the performance, but didn’t i say that the code won’t be very intuitive, may be you should leave a comment you don’t want another developer to come in and think what a fresher why is he checking for the cache key null twice !!! The downside of caching is, you are storing the data outside of the database and the data could be wrong because the updates applied to the database would make the data cached at the web server out of sync. So, how do you invalidate the cache? Well if you only had one way of updating the data lets say only one entry point to the data update you can write some logic to say that every time new data is entered set the cache object to null. But this approach will not work as soon as you have several ways of feeding data to the system or your system is scaled out across a farm of web servers. The perfect solution to this is Micro Caching which means you cache the query for a set time duration and invalidate the cache after that set duration. The advantage is every time the user queries for that data with in the time span for which you have cached the results there are no calls made to the database and the data is served right from the server which makes the response immensely quick. Now figuring out the appropriate time span for which you micro cache the query results really depends on the application. Lets say your website gets 10 requests per second, if you retain the cache results for even 1 minute you will have immense performance gains. You would reduce 90% hits to the database for searching. Ever wondered why when you go to e-bookers.com or xpedia.com or yatra.com to book a flight and you click on the book button because the fare seems too exciting and you get an error message telling you that the fare is not valid any more. Yes, exactly => That is a cache failure! These travel sites or price compare engines are not going to hit the database every time you hit the compare button instead the results will be served from the cache, because the query results are micro cached, its a perfect trade-off, by micro caching the results the site gains 100% performance benefits but every once in a while annoys a customer because the fare has expired. But the trade off works in the favour of these sites as they are still able to process up to 30+ page requests per second which means cater to the site traffic by may be losing 1 customer every once in a while to a competitor who is also using a similar caching technique what are the odds that the user will not come back to their site sooner or later? Recap   Resources Below are some Key resource you might like to review. I would highly recommend the documentation, walkthroughs and videos available on MSDN. You can always make use of Fiddler to debug Web Performance Tests. Some community test extensions and plug ins available on Codeplex might also be of interest to you. The Road Ahead Thank you for taking the time out and reading this blog post, you may also want to read Part I and Part II if you haven’t so far. If you enjoyed the post, remember to subscribe to http://feeds.feedburner.com/TarunArora. Questions/Feedback/Suggestions, etc please leave a comment. Next ‘Load Testing in the cloud’, I’ll be working on exploring the possibilities of running Test controller/Agents in the Cloud. See you on the other side! Thank You!   Share this post : CodeProject

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  • Erlang: 2 database on 2 webserver ??

    - by xRobot
    I have created a blogging system with php+postgresql. Now I want to add a web chat ( in REAL TIME for Million of users simultaneously ) where every message is saved in database. I am thinking to use Erlang+Mnesia on a different webserver for this issue. Message's table will be like this: message_id, user_id, message, date user_id should be related with users table in Postgresql database in another webserver. How can I do that without lose performance ? If you have any other creative solutions tell me please ;).

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  • jquery buttonset()

    - by Kevin
    Hi - I'm using the jquery buttonset() on a set of radio buttons (to tart them up). I'd like to be able to set the selected radio button on another user event. I've been looking into this and while I can set the selected radio button, but I cannot also (easily) update the UI to indicate what the selected radio button is. From what I can tell, I need to call this to set the radio button at index n to be checked $('input[name="transactionsRadio"]')[n].checked = true; And then do some convoluted jquery selector calls to remove the ui-state-active from one lable and apply it to the new label. Is this really the most optimal way to do this ? I had expected an equivalent method to the 'activate' method that is available for the jquery Accordian control. Any more elegant solution would be appreciated! Thanks, Kevin.

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  • Multiple INET sockets (mulple IP's too) connected to UNIX sockets

    - by Andrew
    HOST = same host all the time, accepts multiple connection. I have a dedicated server and I will buy extra IP's. Socket 1 connects to HOST:PORT, from IP-1 Socket 2 connects to HOST:PORT, from IP-1 Socket 3 connects to HOST:PORT, from IP-1 Socket 4 connects to HOST:PORT, from IP-2 Socket 5 connects to HOST:PORT, from IP-2 Socket 6 connects to HOST:PORT, from IP-2 After creating all sockets I want to access them easy as UNIX sockets from PHP. /sys/socket1 /sys/socket2 /sys/socket3 /sys/socket4 /sys/socket5 /sys/socket6 I want the sockets to work in background (like daemon) and I want to be able to connect from PHP to any of this sockets and RECV/SEND whatever I want. I saw "socat" and I think that's the solution for me, please tell me how to use socat, or how to do it other way. Thankyou!

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  • Anyone had any experience with *.pcap manipulation libs?

    - by zxcvbnm
    I'm using the SharpPcap + PacketDotNet libraries to process some .pcap files and came across a bug in the way the timestamps are calculated. Take this Timeval property, which is something along these lines: PosixTimeval Timeval { DateTime Date; ulong Seconds; ulong MicroSeconds; } The problem is as follows: Suppose you have a trace open in Wireshark with one of the packets with a timestamp of "0.002". Once you open it within one of your programs, it retrieves the packet and its Timeval is setup such that Seconds = 0 and MicroSeconds = 002 = 2. This is done under the hood, so there is no way to avoid it as far as I can tell. My question is if that problem is common to other libraries (and maybe all of them?) who manipulate the pcap file format, which I think are built around the same collection of c/c++ functions, or if this is a problem only with the ones I'm using.

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  • WCF Data Services consuming data from EF based repository

    - by John Kattenhorn
    We have an existing repository which is based on EF4 / POCO and is working well. We want to add a service layer using WCF Data Services and looking for some best practice advice. So far we have developed a class which has a IQueryable property and the getter triggers the repository 'get all users' method. The problem so far have been two-fold: 1) It required us to decorate the ID field of the poco object to tell data service what field was the id. This now means that our POCO object is not 'pure'. 2) It cannot figure out the relationships between the objects (which is obvious i guess). I've now stopped this approach and i'm thinking that maybe we should expose the OBjectContext from the repository and use more 'automatic' functionality of EF. Has anybody got any advice or examples of using the repository pattern with WCF Data Services ?

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  • Facebook FQL Question

    - by Michael
    I'm trying to use the Facebook Javascript API to run FQL queries, and it works fine if I try and get users by username or uid, but doesn't work when I'm searching by name. function get_username() { var name = prompt("Enter name: ") FB.api( { method: 'fql.query', query: 'SELECT username FROM user WHERE name in "'+name+'"' }, function(response) { var x = response[0].username alert('Username is ' + x); } ); } I realize that this will probably return multiple users, but I can't figure out how to tell if it's returning multiple users or no users at all, it seems to freeze after trying to get response[0].username. I'm probably making a beginner mistake but any ideas?

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  • Unable to open word file (MSWord 2007) when word automation program is running

    - by sankaran
    In my application i am using word automation to get the text content from the file. It is working fine no issues. But at the instant when word automation is processing, if i open the word file, it is throwing a dialog with message (any file) "This file is in use by another application or user. (C:\User\xyz\AppData...\Normal.dotm)". When close the dialog, it asking for save the file "normal.dotm"...template file. This happens only in MSWord 2007 not in MSWord 2003. can any one tell the solution please.

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  • C# Sleep for 500 milliseconds

    - by ikurtz
    could you please tell me how do i go about pausing my program for 500 milliseconds and then continue? i read thread.sleep(50) is not good as it holds up the GUI thread. using a timer it fires a callback .. i just want to wait 500 and then continue to the next statement. please advise. EDIT: i need to display a status bar message for 500 and then update the message with a different one. sorry i meant 500 not 50.

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