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  • Improving the efficiency of multiple concurrent Core Animation animations

    - by Alex
    I have a view in my app that is very similar to the month view in the built-in Calendar app. There's a subview that holds the individual cells (a custom UIView subclass that draws text into its layer), and when the user navigates to the next "month", I create the new cells and slide the view to show them. When the animation stops, I remove the old, hidden cells and set things up so it's ready to go for the next animation. This all works nicely. However, I'd like to animate the cells' text color, as in the Calendar app, so that the outgoing ones transition to a lighter color and the incoming ones transition to a darker color. The problems is that I can have as many as 70 cells, so doing individual animations is very slow -- between 5-10 fps on my iPhone 3GS. I'm trying to find a less computationally intense way of doing this. My reading of the Shark results is that the majority of the time is spent redrawing the text for each frame for each frame. This makes sense, since text rendering is hardly the cheapest operation. I've considered creating a second view -- one holding the "outgoing" state and one holding the "incoming" state and using a single opacity animation to gradually reveal the updated cells while both are sliding. I'm concerned that instead of having 70 cells, I'll have 140, which seems like a lot of views. So, is that too many views or would there be a better way of doing this?

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  • Why should I install Python packages into `~/.local`?

    - by Matthew Rankin
    Background I don't develop using OS X's system provided Python versions (on OS X 10.6 that's Python 2.5.4 and 2.6.1). I don't install anything in the site-packages directory for the OS provided versions of Python. (The only exception is Mercurial installed from a binary package, which installs two packages in the Python 2.6.1 site-packages directory.) I installed three versions of Python, all using the Mac OS X installer disk image: Python 2.6.6 Python 2.7 Python 3.1.2 I don't like polluting the site-packages directory for my Python installations. So I only install the following five base packages in the site-packages directory. For the actual method/commands used to install these, see SO Question 4324558. setuptools/ez_setup distribute pip virtualenv virtualenvwrapper All other packages are installed in virtualenvs. I am the only user of this MacBook. Questions Given the above background, why should I install the five base packages in ~/.local? Since I'm installing these base packages into the site-packages directories of Python distributions that I've installed, I'm isolated from the OS X's Python distributions. Using this method, should I be concerned about Glyph's comment that other things could potentially break (see his comment below)? Again, I'm only interested in where to install those five base packages. Related Questions/Info I'm asking because of Glyph's comment to my answer to SO question 4314376, which stated: NO. NEVER EVER do sudo python setup.py install whatever. Write a ~/.pydistutils.cfg that puts your pip installation into ~/.local or something. Especially files named ez_setup.py tend to suck down newer versions of things like setuptools and easy_install, which can potentially break other things on your operating system. Previously, I asked What's the proper way to install pip, virtualenv, and distribute for Python?. However, no one answered the "why" of using ~/.local.

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  • CakePHP pagination with HABTM models

    - by nickf
    I'm having some problems with creating pagination with a HABTM relationship. First, the tables and relationships: requests (id, to_location_id, from_location_id) locations (id, name) items_locations (id, item_id, location_id) items (id, name) So, a Request has a Location the request is coming from and a Location the Request is going to. For this question, I'm only concerned about the "to" location. Request --belongsTo--> Location* --hasAndBelongsToMany--> Item (* as "ToLocation") In my RequestController, I want to paginate all the Items in a Request's ToLocation. // RequestsController var $paginate = array( 'Item' => array( 'limit' => 5, 'contain' => array( "Location" ) ) ); // RequestController::add() $locationId = 21; $items = $this->paginate('Item', array( "Location.id" => $locationId )); And this is failing, because it is generating this SQL: SELECT COUNT(*) AS count FROM items Item WHERE Location.id = 21 I can't figure out how to make it actually use the "contain" argument of $paginate... Any ideas?

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  • How can I use SCM on linked files in VS2008 projects?

    - by Tom Bushell
    Background: I'm using Visual-SVN V. 1.7.5 with VS2008. I'm fairly new to SVN. I have a Solution that uses source files that will be shared with other Solutions. I've put these files in a folder called "Shared", and added them to my Solution using "Add - Existing Item... - Add As Link" which works fine as far as VS2008 is concerned. But when I try to add the linked files to SVN using the "Add to Suversion" menu item on the file's context menu, I get a warning: "...not added to Subversion because it is out of working copy. Please setup working copy root using Visual SVN - Set Working Copy Root menu". I tried this, but this seems to change the root directory of the whole solution - not what I want to do. Googling and searching SO indicates that I may want to set up some SVN Externals. I tried to follow the examples, using the command line for the first time with Visual-SVN. But I just got a bunch of error messages I didn't understand. Questions: Are Externals the way to go here? If so, can someone provide some detailed, step-by-step help on how to do this with Visual-SVN?

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  • Any point in subclassing UIButton to create a custom looking button?

    - by glitch
    I want to create a set of buttons that would work and feel very much like the Metro-style tiles that are available on Windows Phones. I would like to allow the user to tap them to access their underlying functionality (open a modal or something or that sort). I'm concerned that subclassing UIButton will not get me there. I need square corners and dynamic content inside the tiles themselves. The posts I've found around SO seem to suggest that subclassing a UIButton would not be a good idea for several reasons and that I should instead use UIView. That reply is from 2010, and I have no idea if in the 2+ years since then there have been considerable changes to how one would achieve that effect. Most users these days will have iOS 5.1+ if not 6.0 soon. Let's say I do go the UIView route. Should I implement UIResponder's touch events or should I instead go the UITapGestureRecognizer route? What's the better practice in 2012? Thank you!

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  • Can you write files in Chrome 8?

    - by greggory.hz
    I'm wondering if, with the new File API exposed in Chrome (I'm not concerned with cross-browser support at this time), it would be possible to write back to files opened via a file input. You can see an example of what I'm trying to accomplish here: http://www.grehz.com/ide. I know I can use server side scripts to dynamically create the files and allow the user to download them normally. I'm hoping that there's a way to accomplish this purely client side. I had read somewhere that you can write to files opened via a file input. I haven't been able to find any examples of this, though I have seen passing references to a FileWriter class. I would be completely not surprised if this wasn't possible though (it seems likely that there are security issues with this). Just looking for some guidance or resources. UPDATE: I was reading here: http://dev.w3.org/2009/dap/file-system/file-writer.html As I was playing around in Chrome, it looks like FileSaver and FileWriter are not implemented, but BlobBuilder is. I can call getBlob() on the BB object, is there any way I can then save that without FileSave or FileWriter?

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  • Can a pc with a 1.2 ghz dual core run VS 2013? [on hold]

    - by moo2
    Edit: This question is about a tool used for programming, Microsoft Visual Studio 2013. I already read the minimum requirements for VS 2013 before I posted or I wouldn't have asked the question. I searched on the web for an answer for a few hours before posting. Why should I go out and spend $400 on a laptop if I can spend less than $100 and use it to learn how to program? In the context of the question it is clear I was not asking for advice on what laptop to buy and it was also clear I was not asking for someone to walk me through the system requirements of VS 2013. This is a vast community and I was wondering if someone in this vast community would have experience in dealing with my question. In other words has anyone ever tried anything like it? If I had an old computer sitting around I would have tested it. At the moment all I have is a friend's Chromebook I'm borrowing. End Edit. I know the requirements for Microsoft Visual Studio 2013 state 1.6 ghz processor. I'm looking at getting a laptop for school and I found one that is old but cheap and would work for college. The Dell D430 I'm looking at getting has a 1.2ghz Core 2 Duo CPU, 80GB HD, 2GB RAM, and Windows 7 Home Premium. It's refurbished. I can get it for less than most phone's cost and from a Microsoft Authorized Refurbisher. I know it's not a skyrim rig but it's lightweight and can handle being a college laptop and doing word processing. Would Visual Studio 2013 run at all? If it is slower I'm not concerned. I just want to know if it would work and compile my assignments and run them? I'd be using this laptop for doing assignments and learning programming languages not for coding the next social media sensation.

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  • Agile Development

    - by James Oloo Onyango
    Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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  • Using HTML 5 SessionState to save rendered Page Content

    - by Rick Strahl
    HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Know more about Cache Buffer Handle

    - by Liu Maclean(???)
    ??????«latch free:cache buffer handles???SQL????»?????cache buffer handle latch?????,?????????: “?????pin?buffer header???????buffer handle,??buffer handle?????????cache buffer handles?,??????cache buffer handles??????,???????cache???buffer handles,?????(reserved set)?????????????_db_handles_cached(???5)???,?????????????????SQL??????????????????????,????pin??????,????????handle,?????????5?cached buffer handles???handle????????????????,Oracle?????????????????pin?”????“?buffer,????????????????handle???db_block_buffers/processes,????_cursor_db_buffers_pinned???????cache buffer handles?????,??????,????????????SQL,????cache?buffer handles?????????,??????????????,???????????/?????” ????T.ASKMACLEAN.COM????,??????cache Buffer handle?????: cache buffer handle ??: ------------------------------ | Buffer state object | ------------------------------ | Place to hang the buffer | ------------------------------ | Consistent Get? | ------------------------------ | Proc Owning SO | ------------------------------ | Flags(RIR) | ------------------------------ ???? cache buffer handle SO: 70000046fdfe530, type: 24, owner: 70000041b018630, flag: INIT/-/-/0×00(buffer) (CR) PR: 70000048e92d148 FLG: 0×500000lock rls: 0, class bit: 0kcbbfbp: [BH: 7000001c7f069b0, LINK: 70000046fdfe570]where: kdswh02: kdsgrp, why: 0BH (7000001c7f069b0) file#: 12 rdba: 0×03061612 (12/398866) class: 1 ba: 7000001c70ee000set: 75 blksize: 8192 bsi: 0 set-flg: 0 pwbcnt: 0dbwrid: 2 obj: 66209 objn: 48710 tsn: 6 afn: 12hash: [700000485f12138,700000485f12138] lru: [70000025af67790,700000132f69ee0]lru-flags: hot_bufferckptq: [NULL] fileq: [NULL] objq: [700000114f5dd10,70000028bf5d620]use: [70000046fdfe570,70000046fdfe570] wait: [NULL]st: SCURRENT md: SHR tch: 0flags: affinity_lockLRBA: [0x0.0.0] HSCN: [0xffff.ffffffff] HSUB: [65535]where: kdswh02: kdsgrp, why: 0 # Example:#   (buffer) (CR) PR: 37290 FLG:    0#   kcbbfbp    : [BH: befd8, LINK: 7836c] (WAITING) Buffer handle (X$KCBBF) kernel cache, buffer buffer_handles Query x$kcbbf  – lists all the buffer handles ???? _db_handles             System-wide simultaneous buffer operations ,no of buffer handles_db_handles_cached      Buffer handles cached each process , no of processes  default 5_cursor_db_buffers_pinned  additional number of buffers a cursor can pin at once_session_kept_cursor_pins       Number of cursors pins to keep in a session When a buffer is pinned it is attached to buffer state object. ??? ???????? cache buffer handles latch ? buffer pin???: SESSION A : SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi PL/SQL Release 10.2.0.5.0 - Production CORE    10.2.0.5.0      Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> create table test_cbc_handle(t1 int); Table created. SQL> insert into test_cbc_handle values(1); 1 row created. SQL> commit; Commit complete. SQL> select rowid from test_cbc_handle; ROWID ------------------ AAANO6AABAAAQZSAAA SQL> select * from test_cbc_handle where rowid='AAANO6AABAAAQZSAAA';         T1 ----------          1 SQL> select addr,name from v$latch_parent where name='cache buffer handles'; ADDR             NAME ---------------- -------------------------------------------------- 00000000600140A8 cache buffer handles SQL> select to_number('00000000600140A8','xxxxxxxxxxxxxxxxxxxx') from dual; TO_NUMBER('00000000600140A8','XXXXXXXXXXXXXXXXXXXX') ----------------------------------------------------                                           1610694824 ??cache buffer handles????parent latch ??? child latch ???SESSION A hold ??????cache buffer handles parent latch ???? oradebug call kslgetl ??, kslgetl?oracle??get latch??? SQL> oradebug setmypid; Statement processed. SQL> oradebug call kslgetl 1610694824 1; Function returned 1 ?????SESSION B ???: SQL> select * from v$latchholder;        PID        SID LADDR            NAME                                                                   GETS ---------- ---------- ---------------- ---------------------------------------------------------------- ----------         15        141 00000000600140A8 cache buffer handles                                                    119 cache buffer handles latch ???session A hold??,????????acquire cache buffer handle latch SQL> select * from test_cbc_handle where rowid='AAANO6AABAAAQZSAAA';         T1 ----------          1 ?????Server Process?????? read buffer, ????????"_db_handles_cached", ??process?cache 5? cache buffer handle ??"_db_handles_cached"=0,?process????5????cache buffer handle , ???? process ???pin buffer,???hold cache buffer handle latch??????cache buffer handle SQL> alter system set "_db_handles_cached"=0 scope=spfile; System altered. ????? shutdown immediate; startup; session A: SQL> oradebug setmypid; Statement processed. SQL> oradebug call kslgetl 1610694824 1; Function returned 1 session B: select * from test_cbc_handle where rowid='AAANO6AABAAAQZSAAA'; session B hang!! WHY? SQL> oradebug setmypid; Statement processed. SQL> oradebug dump systemstate 266; Statement processed.   SO: 0x11b30b7b0, type: 2, owner: (nil), flag: INIT/-/-/0x00   (process) Oracle pid=22, calls cur/top: (nil)/0x11b453c38, flag: (0) -             int error: 0, call error: 0, sess error: 0, txn error 0   (post info) last post received: 0 0 0               last post received-location: No post               last process to post me: none               last post sent: 0 0 0               last post sent-location: No post               last process posted by me: none     (latch info) wait_event=0 bits=8       holding    (efd=4) 600140a8 cache buffer handles level=3   SO: 0x11b305810, type: 2, owner: (nil), flag: INIT/-/-/0x00   (process) Oracle pid=10, calls cur/top: 0x11b455ac0/0x11b450a58, flag: (0) -             int error: 0, call error: 0, sess error: 0, txn error 0   (post info) last post received: 0 0 0               last post received-location: No post               last process to post me: none               last post sent: 0 0 0               last post sent-location: No post               last process posted by me: none     (latch info) wait_event=0 bits=2         Location from where call was made: kcbzgs:       waiting for 600140a8 cache buffer handles level=3 FBD93353:000019F0    10   162 10005   1 KSL WAIT BEG [latch: cache buffer handles] 1610694824/0x600140a8 125/0x7d 0/0x0 FF936584:00002761    10   144 10005   1 KSL WAIT BEG [latch: cache buffer handles] 1610694824/0x600140a8 125/0x7d 0/0x0 PID=22 holding ??cache buffer handles latch PID=10 ?? cache buffer handles latch, ????"_db_handles_cached"=0 ?? process??????cache buffer handles ??systemstate???? kcbbfbp cache buffer handle??, ?? "_db_handles_cached"=0 ? cache buffer handles latch?hold ?? ????cache buffer handles latch , ??? buffer?pin?????????? session A exit session B: SQL> select * from v$latchholder; no rows selected SQL> insert into test_cbc_handle values(2); 1 row created. SQL> commit; Commit complete. SQL> SQL> select t1,rowid from test_cbc_handle;         T1 ROWID ---------- ------------------          1 AAANPAAABAAAQZSAAA          2 AAANPAAABAAAQZSAAB SQL> select spid,pid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat)); SPID                PID ------------ ---------- 19251                10 ? GDB ? SPID=19215 ?debug , ?? kcbrls ????breakpoint ??? ????release buffer [oracle@vrh8 ~]$ gdb $ORACLE_HOME/bin/oracle 19251 GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-37.el5) Copyright (C) 2009 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.  Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-redhat-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... Reading symbols from /s01/oracle/product/10.2.0.5/db_1/bin/oracle...(no debugging symbols found)...done. Attaching to program: /s01/oracle/product/10.2.0.5/db_1/bin/oracle, process 19251 Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libskgxp10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libskgxp10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libhasgen10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libhasgen10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libskgxn2.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libskgxn2.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libocr10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libocr10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libocrb10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libocrb10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libocrutl10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libocrutl10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libjox10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libjox10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libclsra10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libclsra10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libdbcfg10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libdbcfg10.so Reading symbols from /s01/oracle/product/10.2.0.5/db_1/lib/libnnz10.so...(no debugging symbols found)...done. Loaded symbols for /s01/oracle/product/10.2.0.5/db_1/lib/libnnz10.so Reading symbols from /usr/lib64/libaio.so.1...(no debugging symbols found)...done. Loaded symbols for /usr/lib64/libaio.so.1 Reading symbols from /lib64/libdl.so.2...(no debugging symbols found)...done. Loaded symbols for /lib64/libdl.so.2 Reading symbols from /lib64/libm.so.6...(no debugging symbols found)...done. Loaded symbols for /lib64/libm.so.6 Reading symbols from /lib64/libpthread.so.0...(no debugging symbols found)...done. [Thread debugging using libthread_db enabled] Loaded symbols for /lib64/libpthread.so.0 Reading symbols from /lib64/libnsl.so.1...(no debugging symbols found)...done. Loaded symbols for /lib64/libnsl.so.1 Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done. Loaded symbols for /lib64/libc.so.6 Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done. Loaded symbols for /lib64/ld-linux-x86-64.so.2 Reading symbols from /lib64/libnss_files.so.2...(no debugging symbols found)...done. Loaded symbols for /lib64/libnss_files.so.2 0x00000035c000d940 in __read_nocancel () from /lib64/libpthread.so.0 (gdb) break kcbrls Breakpoint 1 at 0x10e5d24 session B: select * from test_cbc_handle where rowid='AAANPAAABAAAQZSAAA'; select hang !! GDB (gdb) c Continuing. Breakpoint 1, 0x00000000010e5d24 in kcbrls () (gdb) bt #0  0x00000000010e5d24 in kcbrls () #1  0x0000000002e87d25 in qertbFetchByUserRowID () #2  0x00000000030c62b8 in opifch2 () #3  0x00000000032327f0 in kpoal8 () #4  0x00000000013b7c10 in opiodr () #5  0x0000000003c3c9da in ttcpip () #6  0x00000000013b3144 in opitsk () #7  0x00000000013b60ec in opiino () #8  0x00000000013b7c10 in opiodr () #9  0x00000000013a92f8 in opidrv () #10 0x0000000001fa3936 in sou2o () #11 0x000000000072d40b in opimai_real () #12 0x000000000072d35c in main () SQL> oradebug setmypid; Statement processed. SQL> oradebug dump systemstate 266; Statement processed. ?????? kcbbfbp buffer cache handle ?  SO state object ? BH BUFFER HEADER  link???     ----------------------------------------     SO: 0x11b452348, type: 3, owner: 0x11b305810, flag: INIT/-/-/0x00     (call) sess: cur 11b41bd18, rec 0, usr 11b41bd18; depth: 0       ----------------------------------------       SO: 0x1182dc750, type: 24, owner: 0x11b452348, flag: INIT/-/-/0x00       (buffer) (CR) PR: 0x11b305810 FLG: 0x108000       class bit: (nil)       kcbbfbp: [BH: 0xf2fc69f8, LINK: 0x1182dc790]       where: kdswh05: kdsgrp, why: 0       BH (0xf2fc69f8) file#: 1 rdba: 0x00410652 (1/67154) class: 1 ba: 0xf297c000         set: 3 blksize: 8192 bsi: 0 set-flg: 2 pwbcnt: 272         dbwrid: 0 obj: 54208 objn: 54202 tsn: 0 afn: 1         hash: [f2fc47f8,1181f3038] lru: [f2fc6b88,f2fc6968]         obj-flags: object_ckpt_list         ckptq: [1182ecf38,1182ecf38] fileq: [1182ecf58,1182ecf58] objq: [108712a28,108712a28]         use: [1182dc790,1182dc790] wait: [NULL]         st: XCURRENT md: SHR tch: 12         flags: buffer_dirty gotten_in_current_mode block_written_once                 redo_since_read         LRBA: [0xc7.73b.0] HSCN: [0x0.1cbe52] HSUB: [1]         Using State Objects           ----------------------------------------           SO: 0x1182dc750, type: 24, owner: 0x11b452348, flag: INIT/-/-/0x00           (buffer) (CR) PR: 0x11b305810 FLG: 0x108000           class bit: (nil)           kcbbfbp: [BH: 0xf2fc69f8, LINK: 0x1182dc790]           where: kdswh05: kdsgrp, why: 0         buffer tsn: 0 rdba: 0x00410652 (1/67154)         scn: 0x0000.001cbe52 seq: 0x01 flg: 0x02 tail: 0xbe520601         frmt: 0x02 chkval: 0x0000 type: 0x06=trans data tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x0  cc: 1 col  0: [ 2]  c1 02 tab 0, row 1, @0x1f94 tl: 6 fb: --H-FL-- lb: 0x2  cc: 1 col  0: [ 2]  c1 15 end_of_block_dump         (buffer) (CR) PR: 0x11b305810 FLG: 0x108000 st: XCURRENT md: SHR tch: 12 ? buffer header?status= XCURRENT mode=KCBMSHARE KCBMSHR     current share ?????  x$kcbbf ????? cache buffer handle SQL> select distinct KCBBPBH from  x$kcbbf ; KCBBPBH ---------------- 00 00000000F2FC69F8            ==>0xf2fc69f8 SQL> select * from x$kcbbf where kcbbpbh='00000000F2FC69F8'; ADDR                   INDX    INST_ID KCBBFSO_TYP KCBBFSO_FLG KCBBFSO_OWN ---------------- ---------- ---------- ----------- ----------- ----------------   KCBBFFLG    KCBBFCR    KCBBFCM KCBBFMBR         KCBBPBH ---------- ---------- ---------- ---------------- ---------------- KCBBPBF          X0KCBBPBH        X0KCBBPBF        X1KCBBPBH ---------------- ---------------- ---------------- ---------------- X1KCBBPBF        KCBBFBH            KCBBFWHR   KCBBFWHY ---------------- ---------------- ---------- ---------- 00000001182DC750        748          1          24           1 000000011B452348    1081344          1          0 00               00000000F2FC69F8 00000001182DC750 00               00000001182DC750 00 00000001182DC7F8 00                      583          0 SQL> desc x$kcbbf;  Name                                      Null?    Type  ----------------------------------------- -------- ----------------------------  ADDR                                               RAW(8)  INDX                                               NUMBER  INST_ID                                            NUMBER  KCBBFSO_TYP                                        NUMBER  KCBBFSO_FLG                                        NUMBER  KCBBFSO_OWN                                        RAW(8)  KCBBFFLG                                           NUMBER  KCBBFCR                                            NUMBER  KCBBFCM                                            NUMBER  KCBBFMBR                                           RAW(8)  KCBBPBH                                            RAW(8)  KCBBPBF                                            RAW(8)  X0KCBBPBH                                          RAW(8)  X0KCBBPBF                                          RAW(8)  X1KCBBPBH                                          RAW(8)  X1KCBBPBF                                          RAW(8)  KCBBFBH                                            RAW(8)  KCBBFWHR                                           NUMBER  KCBBFWHY                                           NUMBER gdb ?? ?process??????kcbrls release buffer? ???cache buffer handle??? SQL> select distinct KCBBPBH from  x$kcbbf ; KCBBPBH ---------------- 00

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  • Know More About Oracle Row Lock

    - by Liu Maclean(???)
    ??????Oracle??????????row lock,??ORACLE????????????????????,row lock???????????????????????????????,??Server Process?pin????block buffer????????? ????????,?process A ??update???????? Z?????????, ???????rollback???commit;??Process B??????DML??, ???????rowid???? Z???, ???????????process A????????ITL???,????????cleanout??,????????row???????????commit, ???????Process B????”enq: TX – row lock contention”??????? ????Process B????????????? ?????????Process A???????row,??Process B???????”enq: TX – row lock contention”???? ????????  ????????: SESSION A: SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi PL/SQL Release 10.2.0.5.0 - Production CORE    10.2.0.5.0      Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> create table maclean_lock(t1 int); Table created. SQL> insert into maclean_lock values (1); 1 row created. SQL> commit; Commit complete. SQL> select dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid) from maclean_lock; DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) ------------------------------------ ------------------------------------                                67642                                    1 SQL>  select distinct sid from v$mystat;        SID ----------        142 SQL> select pid,spid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat));        PID SPID ---------- ------------         17 15636 ??SESSION A ????savepoint ,?update ?????????         SQL>  savepoint NONLOCK; Savepoint created. SQL> select * From v$Lock where sid=142; no rows selected SQL> set linesize 140 pagesize 1400 SQL>  update maclean_lock set t1=t1+2; 1 row updated. SQL> select * From v$Lock where sid=142; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 0000000091FC69F0 0000000091FC6A18        142 TM      55829          0          3          0          6          0 00000000914B4008 00000000914B4040        142 TX     393232        609          6          0          6          0         SQL> select dump(3,16) from dual; DUMP(3,16) -------------------------------------------------------------------------------- Typ=2 Len=2: c1,4 ALTER SYSTEM DUMP DATAFILE 1 BLOCK 67642;  Object id on Block? Y  seg/obj: 0xda16  csc: 0x00.234718  itc: 2  flg: O  typ: 1 - DATA      fsl: 0  fnx: 0x0 ver: 0x01  Itl           Xid                  Uba         Flag  Lck        Scn/Fsc 0x01   0x000a.00f.000001e0  0x00800075.02a6.29  C---    0  scn 0x0000.00234711 0x02   0x0007.018.000001fe  0x0080065c.017a.02  ----    1  fsc 0x0000.00000000 data_block_dump,data header at 0x81d185c =============== tsiz: 0x1fa0 hsiz: 0x14 pbl: 0x081d185c bdba: 0x0041083a      76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f9a avsp=0x1f83 tosp=0x1f83 0xe:pti[0]      nrow=1  offs=0 0x12:pri[0]     offs=0x1f9a block_row_dump: tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x2  cc: 1 col  0: [ 2]  c1 04 end_of_block_dump ?? BLOCK DUMP ???? ??????XID=0x0007.018.000001fe ?transaction?? lb:0x1 ??SESSION B ,?????UPDATE?? ???enq: TX - row lock contention ?? SQL> select distinct sid from v$mystat;        SID ----------        140 SQL> select pid,spid from v$process where addr = ( select paddr from v$session where sid=(select distinct sid from v$mystat));        PID SPID ---------- ------------         24 15652 SQL> alter system set "_trace_events"='10000-10999:255:24'; System altered.         SQL> update maclean_lock set t1=t1+2; select * From v$Lock where sid=142 or sid=140 order by sid; SESSION C: SQL> select * From v$Lock where sid=142 or sid=140 order by sid; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 0000000091FC6B10 0000000091FC6B38        140 TM      55829          0          3          0         84          0 00000000924F4A58 00000000924F4A78        140 TX     458776        510          0          6         84          0 00000000914B51E8 00000000914B5220        142 TX     458776        510          6          0        312          1 0000000091FC69F0 0000000091FC6A18        142 TM      55829          0          3          0        312          0 ???? SESSION B SID=140 ?SESSION A ?TX ENQUEUE ?X mode?REQUEST SQL> oradebug dump systemstate 266; Statement processed. SESSION B waiter's enqueue lock       SO: 0x924f4a58, type: 5, owner: 0x92bb8dc8, flag: INIT/-/-/0x00       (enqueue) TX-00070018-000001FE    DID: 0001-0018-00000022       lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  res_flag: 0x6       req: X, lock_flag: 0x0, lock: 0x924f4a78, res: 0x925617c0       own: 0x92b76be0, sess: 0x92b76be0, proc: 0x92a737a0, prv: 0x925617e0 TX-00070018-000001FE=> TX 458776 510 SESSION A owner's enqueue lock       SO: 0x914b51e8, type: 40, owner: 0x92b796d0, flag: INIT/-/-/0x00       (trans) flg = 0x1e03, flg2 = 0xc0000, prx = 0x0, ros = 2147483647 bsn = 0xed5 bndsn = 0xee7 spn = 0xef7       efd = 3       file:xct.c lineno:1179       DID: 0001-0011-000000C2       parent xid: 0x0000.000.00000000       env: (scn: 0x0000.00234718  xid: 0x0007.018.000001fe  uba: 0x0080065c.017a.02  statement num=0  parent xid: xid: 0x0000.000.00000000  scn: 0x00 00.00234718 0sch: scn: 0x0000.00000000)       cev: (spc = 7818  arsp = 914e8310  ubk tsn: 1 rdba: 0x0080065c  useg tsn: 1 rdba: 0x00800069             hwm uba: 0x0080065c.017a.02  col uba: 0x00000000.0000.00             num bl: 1 bk list: 0x91435070)             cr opc: 0x0 spc: 7818 uba: 0x0080065c.017a.02       (enqueue) TX-00070018-000001FE    DID: 0001-0011-000000C2       lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  res_flag: 0x6       mode: X, lock_flag: 0x0, lock: 0x914b5220, res: 0x925617c0       own: 0x92b796d0, sess: 0x92b796d0, proc: 0x92a6ffd8, prv: 0x925617d0        xga: 0x8b7c6d40, heap: UGA       Trans IMU st: 2 Pool index 65535, Redo pool 0x914b58d0, Undo pool 0x914b59b8       Redo pool range [0x86de640 0x86de640 0x86e0e40]       Undo pool range [0x86dbe40 0x86dbe40 0x86de640]         ----------------------------------------         SO: 0x91435070, type: 39, owner: 0x914b51e8, flag: -/-/-/0x00         (List of Blocks) next index = 1         index   itli   buffer hint   rdba       savepoint         -----------------------------------------------------------             0      2   0x647f1fc8    0x41083a     0xee7 ?SESSION A? ROLLBACK ?savepoint: SQL> rollback to NONLOCK; Rollback complete. ????savepoint ??update??????? ??UPDATE???????? ROLLBACK: SQL> select * From v$Lock where sid=142 or sid=140; ADDR             KADDR                   SID TY        ID1        ID2      LMODE    REQUEST      CTIME      BLOCK ---------------- ---------------- ---------- -- ---------- ---------- ---------- ---------- ---------- ---------- 00000000924F4A58 00000000924F4A78        140 TX     458776        510          0          6        822          0 0000000091FC6B10 0000000091FC6B38        140 TM      55829          0          3          0        822          0 00000000914B51E8 00000000914B5220        142 TX     458776        510          6          0       1050          1 ???? SESSION A 142 ???SAVEPOINT ???????TM LOCK ????? ROLLBACK TO SAVEPOINT?????SESSION???TX LOCK!!!! ??????SESSION 142???TX ID1=458776 ID2=510, ????ROLLBACK TO SAVEPOINT?????????ABORT TRANSACTION ?? SESSION B  SID=140??  SESSION A ?? , ?????????SESSION B? update???HANG?? ?????????CACHE?????:  Object id on Block? Y  seg/obj: 0xda16  csc: 0x00.2347b7  itc: 2  flg: O  typ: 1 - DATA      fsl: 0  fnx: 0x0 ver: 0x01  Itl           Xid                  Uba         Flag  Lck        Scn/Fsc 0x01   0x000a.00f.000001e0  0x00800075.02a6.29  C---    0  scn 0x0000.00234711 0x02   0x0000.000.00000000  0x00000000.0000.00  ----    0  fsc 0x0000.00000000 data_block_dump,data header at 0x745d85c =============== tsiz: 0x1fa0 hsiz: 0x14 pbl: 0x0745d85c bdba: 0x0041083a      76543210 flag=-------- ntab=1 nrow=1 frre=-1 fsbo=0x14 fseo=0x1f9a avsp=0x1f83 tosp=0x1f83 0xe:pti[0]      nrow=1  offs=0 0x12:pri[0]     offs=0x1f9a block_row_dump: tab 0, row 0, @0x1f9a tl: 6 fb: --H-FL-- lb: 0x0  cc: 1 col  0: [ 2]  c1 02 end_of_block_dump ???? ITL=0x02? ?????????,col  0: [ 2]  c1 02 ????????? ?????????SESSION D ,??????row lock?? ?UPDATE???????? SESSION D: SQL> update maclean_lock set t1=t1+2; 1 row updated. SQL> rollback; Rollback complete. ??SESSION B ??????????? ?????ORACLE????????, ??????????? TX lock?? row lock , ????????2??? row lock?????????, ?TX lock????????ENQUEUE LOCK???? ?????????PROCESS K?DML???????????????????????,??????????TX LOCK, ????PROCESS Z?????????????????????????ROW LOCK????????, ???????OLTP?????????????????????? ??ROW LOCK?Release ??????TX?ENQUEUE LOCK,?????????Process J ????????????, Process K??????????? ,Process K?????????,???row piece?lb??0x0 ,?????ITL, Process Z???ITL???????Process J????XID,?????Process J?????TX lock, PROCESS K ???TX resource?Enqueue Waiter Linked List?????X mode(exclusive)?enqueue lock? ???Process J??TX lock?,Process J?????TX resource?Enqueue Waiter Linked List ???Process K??????,??POST?????Process K? TX lock??????, ???????row lock???????,????????? ?????????? ?????: SESSION A ???PID =17 ?????????????????? SESSION B ???PID =24 ??????? "_trace_events"='10000-10999:255:24';  KST trace ??????? Server Process??? SESSION A PID=17  ?? acqure?SX mode???TM Lock ,?? ????Transaction?????UNDO SEGMENT 7,???XID 7.24.510, ?acquire ?X mode? TX-00070018-000001fe ? ?????? 00070018-000001fe ???? 7- 24 - 510? XID ? 781F4B8A:007A569C    17   142 10704  83 ksqgtl: acquire TM-0000da15-00000000 mode=SX flags=GLOBAL|XACT why="contention" 781F4B92:007A569D    17   142 10704  19 ksqgtl: SUCCESS 781F4BB3:007A569E    17   142 10812   2 0x000000000041083A 0x0000000000000000 0x0000000000234717 781F4BBA:007A569F    17   142 10812   3 0x0000000000000000 0x0000000000000000 0x0000000000000000 781F4BC0:007A56A0    17   142 10812   4 0x0000000000000000 0x0000000000000000 0x0000000000000000 781F4BD3:007A56A1    17   142 10812   5 0x000000000041083A 0x0000000000000000 0x0000000000000000 781F4BFE:007A56A2    17   142 10811   1 0x000000000041083A 0x0000000000000000 0x0000000000234711 0x0000000000000002 781F4C06:007A56A3    17   142 10811   2 0x000000000041083A 0x0000000000000000 0x0000000000234718 0x00007FA074EDA560 781F4C26:007A56A4    17   142 10813   1 ktubnd: Bind usn 7 nax 1 nbx 0 lng 0 par 0 781F4C43:007A56A5    17   142 10813   2 ktubnd: Txn Bound xid: 7.24.510 781F4C4A:007A56A6    17   142 10704  83 ksqgtl: acquire TX-00070018-000001fe mode=X flags=GLOBAL|XACT why="contention" 781F4C51:007A56A7    17   142 10704  19 ksqgtl: SUCCESS ?????????? ???????? 781F4CBF:007A56A8    17   142 10005   1 KSL WAIT BEG [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 781F4CCC:007A56A9    17   142 10005   2 KSL WAIT END [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 time=13 781F4CDE:007A56AA    17   142 10005   1 KSL WAIT BEG [SQL*Net message from client] 1650815232/0x62657100 1/0x1 0/0x0 786BD85D:007A57E0    17   142 10005   2 KSL WAIT END [SQL*Net message from client] 1650815232/0x62657100 1/0x1 0/0x0 time=5016447 786BD966:007A57E1    17   142 10005   1 KSL WAIT BEG [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 786BD96E:007A57E2    17   142 10005   2 KSL WAIT END [SQL*Net message to client] 1650815232/0x62657100 1/0x1 0/0x0 time=8 SESSION B ???PID =24  ,??????? SX mode? TM lock,??row lock? acquire X mode?TX-00070018-000001fe ksqgtl: acquire TM-0000da15-00000000 mode=SX flags=GLOBAL|XACT why="contention" ksqgtl: SUCCESS 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000000000001 0x000000000041083A 0x0000000000000000 0x00000000002354F8 0x0000000008A63780 0x0000000000000001 0x0000000000800861 0x0000000000000241 0x0000000000000001 0x000000000041083A 0x0000000000000001 0x0000000000000001 0x000000000041083A 0x0000000000000000 0x00000000002354F9 0x0000000000000002 ksqgtl: acquire TX-00070018-000001fe mode=X flags=GLOBAL|LONG why="row lock contention" C4048EBD:007F52B6    24   140 10005   2 KSL WAIT END [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe time=2929879 C4048ED4:007F52B7    24   140 10005   1 KSL WAIT BEG [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe C43146CA:007F535E    24   140 10005   2 KSL WAIT END [enq: TX - row lock contention] 1415053318/0x54580006 458776/0x70018 510/0x1fe time=2930676 ????????? ,PID=24 ??????ksqcmi???????? deadlock C43146D9:007F535F    24   140 10704 134 ksqcmi: performing local deadlock detection on TX-00070018-000001fe C43146F8:007F5360    24   140 10704 150 ksqcmi: deadlock not detected on TX-00070018-000001fe ?? ??? PID 17 ??ROLLBACK ???? ,????????: PID 17 ROLLBACK; D7A495BB:007F9D3E    17   142 10005   4 KSL POST SENT postee=24 loc='ksqrcl' id1=0 id2=0 name=   type=0 D7A495D8:007F9D3F    17   142 10444  12 ABORT TRANSACTION - xid: 0x0007.018.000001fe ??  PID 17 ??? TX resource?Enqueue Waiter linked List ???PID 24???,????KSL POST SENT ?? PID 24, ???ksqrcl???ENQUEUE LOCK ?PID 24??????KSL POST (KSL POST RCVD poster=17), ?ksqgtl???? TX-00070018-000001fe ?? ksqrcl??, ??PID 24???????? TX lock?USN ,??????? USN 3 XID 3.11.582 ,???acquire TX-0003000b-00000246 D7A49616:007F9D41    24   140 10005   3 KSL POST RCVD poster=17 loc='ksqrcl' id1=0 id2=0 name=   type=0 fac#=0 facpost=1 D7A4961C:007F9D42    24   140 10704  19 ksqgtl: SUCCESS D7A4967D:007F9D43    24   140 10704 117 ksqrcl: release TX-00070018-000001fe mode=X D7A496A5:007F9D44    24   140 10813   1 ktubnd: Bind usn 3 nax 1 nbx 0 lng 0 par 0 D7A496C2:007F9D45    24   140 10813   2 ktubnd: Txn Bound xid: 3.11.582 D7A496C7:007F9D46    24   140 10704  83 ksqgtl: acquire TX-0003000b-00000246 mode=X flags=GLOBAL|XACT why="contention" D7A496E4:007F9D47    24   140 10704  19 ksqgtl: SUCCESS ROW LOCK?Release ??????TX?ENQUEUE LOCK,?????????Process J ????????????, Process K??????????? ,Process K?????????,???row piece?lb??0×0 ,?????ITL,Process Z???ITL???????Process J????XID,?????Process J?????TX lock,PROCESS K ???TX resource?Enqueue Waiter Linked List?????X mode(exclusive)?enqueue lock? ???Process J??TX lock?,Process J?????TX resource?Enqueue Waiter Linked List ???Process K??????,??POST?????Process K? TX lock??????,???????row lock???????,?????????

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  • How to Edit data in nested Listview

    - by miti737
    I am using listview to display a list of items and a nested listview to show list of features to each item. Both parent and child listview need to able Insert,Edit and delete operation. It works fine for parent listview. But when I try to edit an child item, The edit button does not take it into Edit mode. Can you please suggest me what I am missing in my code? <asp:ListView ID="lvParent" runat="server" OnItemDataBound="lvParent_ItemDataBound" onitemcanceling="lvParent_ItemCanceling" onitemcommand="lvParent_ItemCommand" DataKeyNames="ItemID" onitemdeleting="lvParent_ItemDeleting" oniteminserting="lvParent_ItemInserting" > <LayoutTemplate> <asp:PlaceHolder ID="itemPlaceholder" runat="server"></asp:PlaceHolder> <div align="right"> <asp:Button ID="btnInsert" runat="server" Text="ADD Item" onclick="btnInsert_Click"/> </div> </LayoutTemplate> <ItemTemplate> <table runat="server" cellpadding="0" cellspacing="0" border="0" width="100%"> <tr> <td> <div id="dvDetail"> <span >Description</span> <asp:TextBox ID="txtDescription" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "Description") %>' TextMode="MultiLine" ></asp:TextBox> </div> <div id="dvFeature" > <span>Feature List</span> <asp:ListView ID="lvChild" runat="server" InsertItemPosition="LastItem" DataKeyNames="FeatureID" OnItemCommand="lvChild_ItemCommand" OnItemCanceling="lvChild_ItemCanceling" OnItemDeleting="lvChild_ItemDeleting" OnItemEditing="lvChild_ItemEditing" OnItemInserting="lvChild_ItemInserting" OnItemUpdating="lvChild_ItemUpdating" DataSource='<%# DataBinder.Eval(Container.DataItem, "FeatureList") %>' > <LayoutTemplate> <ul > <asp:PlaceHolder runat="server" ID="itemPlaceHolder" ></asp:PlaceHolder> </ul> </LayoutTemplate> <ItemTemplate> <li> <span class="dvList"><%# DataBinder.Eval(Container.DataItem, "FeatureTitle")%></span> <div class="dvButton" > <asp:ImageButton ID="btnEdit" runat="server" ImageUrl="/Images/edit_16x16.gif" AlternateText= "Edit" CommandName="Edit" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "FeatureID") %>' Width="12" Height="12" /> <asp:ImageButton ID="btnDelete" runat="server" ImageUrl="/Images/delete_16x16.gif" AlternateText= "Delete" CommandName="Delete" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "FeatureID") %>' Width="12" Height="12" /> </div> </li> </ItemTemplate> <EditItemTemplate> <li> <asp:TextBox ID="txtFeature" Text='<%# DataBinder.Eval(Container.DataItem, "FeatureTitle")%>' runat="server"></asp:TextBox> <div class="dvButton"> <asp:ImageButton ID="btnUpdate" runat="server" ImageUrl="/Images/ok_16x16.gif" AlternateText= "Update" CommandName="Update" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "FeatureID") %>' Width="12" Height="12" /> <asp:ImageButton ID="btnCancel" runat="server" ImageUrl="/Images/delete_16x16.gif" AlternateText= "Cancel" CommandName="Cancel" Width="12" Height="12" CausesValidation="false" /> </div> </li> </EditItemTemplate> <InsertItemTemplate> <asp:TextBox ID="txtFeature" runat="server"></asp:TextBox> <div class="dvButton"> <asp:ImageButton ID="btnInsert" runat="server" ImageUrl="/Images/ok_16x16.gif" AlternateText= "Insert" CommandName="Insert" Width="12" Height="12" /> <asp:ImageButton ID="btnCancel" runat="server" ImageUrl="/Images/delete_16x16.gif" AlternateText= "Cancel" CommandName="Cancel" Width="12" Height="12" CausesValidation="false" /> </div> </InsertItemTemplate> </asp:ListView> </div> </td> </tr> <tr> <td align="right"> <div id="dvButton" > <asp:Button ID="btnSave" runat="server" Text="Save" CommandName="Save" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "ItemID") %>' /> <asp:Button ID="btnDelete" runat="server" Text="Delete" CssClass="Cancel" CommandName="Delete" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "ItemID") %>' /> </div> </td> </tr> </table> </ItemTemplate> </asp:ListView> Code Behind: protected void Page_Load(object sender, EventArgs e) { if (Page.IsPostBack == false) { BindData(); } } private void BindData() { MyDataContext data = new MyDataContext(); var result = from itm in data.ItemLists where itm.ItemID == iItemID select new { itm.ItemID, itm.Description, FeatureList = itm.Features }; lvParent.DataSource = result; lvParent.DataBind(); } protected void lvChild_ItemEditing(object sender, ListViewEditEventArgs e) { ListView lvChild = sender as ListView; lvChild.EditIndex = e.NewEditIndex; lvChild.DataBind(); } Edit: protected void lvChild_ItemEditing(object sender, ListViewEditEventArgs e) { ListView lvChild = sender as ListView; lvChild.EditIndex = e.NewEditIndex; lvChild.DataBind(); } If I use "lvChild.DataBind()" in 'ItemEditing' event, the total list of child items goes away if I click 'edit' protected void lvChild_ItemEditing(object sender, ListViewEditEventArgs e) { ListView lvChild = sender as ListView; lvChild.EditIndex = e.NewEditIndex; } if I get rid of 'lvChild.Databind' in ItemEditing event, it goes to Edit mode after clicking the 'edit' button twice . And though it shows textbox control of EditItemTemplate, it appears as a blank textbox (does not bind existing value to edit).

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  • Bindable richTextBox still hanging in memory {WPF, Caliburn.Micro}

    - by Paul
    Hi, I use in WFP Caliburn.Micro Framework. I need bindable richTextbox for Document property. I found many ways how do it bindable richTextBox. But I have one problem. From parent window I open child window. Child window consist bindable richTextBox user control. After I close child window and use memory profiler view class with bindabelrichTextBox control and view model class is still hanging in memory. - this cause memory leaks. If I use richTextBox from .NET Framework or richTextBox from Extended WPF Toolkit it doesn’t cause this memory leak problem. I can’t identified problem in bindable richTextBox class. Here is ist class for bindable richTextBox: Base class can be from .NET or Extended toolkit. /// <summary> /// Represents a bindable rich editing control which operates on System.Windows.Documents.FlowDocument /// objects. /// </summary> public class BindableRichTextBox : RichTextBox { /// <summary> /// Identifies the <see cref="Document"/> dependency property. /// </summary> public static readonly DependencyProperty DocumentProperty = DependencyProperty.Register("Document", typeof(FlowDocument), typeof(BindableRichTextBox)); /// <summary> /// Initializes a new instance of the <see cref="BindableRichTextBox"/> class. /// </summary> public BindableRichTextBox() : base() { } /// <summary> /// Initializes a new instance of the <see cref="BindableRichTextBox"/> class. /// </summary> /// <param title="document">A <see cref="T:System.Windows.Documents.FlowDocument"></see> to be added as the initial contents of the new <see cref="T:System.Windows.Controls.BindableRichTextBox"></see>.</param> public BindableRichTextBox(FlowDocument document) : base(document) { } /// <summary> /// Raises the <see cref="E:System.Windows.FrameworkElement.Initialized"></see> event. This method is invoked whenever <see cref="P:System.Windows.FrameworkElement.IsInitialized"></see> is set to true internally. /// </summary> /// <param title="e">The <see cref="T:System.Windows.RoutedEventArgs"></see> that contains the event data.</param> protected override void OnInitialized(EventArgs e) { // Hook up to get notified when DocumentProperty changes. DependencyPropertyDescriptor descriptor = DependencyPropertyDescriptor.FromProperty(DocumentProperty, typeof(BindableRichTextBox)); descriptor.AddValueChanged(this, delegate { // If the underlying value of the dependency property changes, // update the underlying document, also. base.Document = (FlowDocument)GetValue(DocumentProperty); }); // By default, we support updates to the source when focus is lost (or, if the LostFocus // trigger is specified explicity. We don't support the PropertyChanged trigger right now. this.LostFocus += new RoutedEventHandler(BindableRichTextBox_LostFocus); base.OnInitialized(e); } /// <summary> /// Handles the LostFocus event of the BindableRichTextBox control. /// </summary> /// <param title="sender">The source of the event.</param> /// <param title="e">The <see cref="System.Windows.RoutedEventArgs"/> instance containing the event data.</param> void BindableRichTextBox_LostFocus(object sender, RoutedEventArgs e) { // If we have a binding that is set for LostFocus or Default (which we are specifying as default) // then update the source. Binding binding = BindingOperations.GetBinding(this, DocumentProperty); if (binding.UpdateSourceTrigger == UpdateSourceTrigger.Default || binding.UpdateSourceTrigger == UpdateSourceTrigger.LostFocus) { BindingOperations.GetBindingExpression(this, DocumentProperty).UpdateSource(); } } /// <summary> /// Gets or sets the <see cref="T:System.Windows.Documents.FlowDocument"></see> that represents the contents of the <see cref="T:System.Windows.Controls.BindableRichTextBox"></see>. /// </summary> /// <value></value> /// <returns>A <see cref="T:System.Windows.Documents.FlowDocument"></see> object that represents the contents of the <see cref="T:System.Windows.Controls.BindableRichTextBox"></see>.By default, this property is set to an empty <see cref="T:System.Windows.Documents.FlowDocument"></see>. Specifically, the empty <see cref="T:System.Windows.Documents.FlowDocument"></see> contains a single <see cref="T:System.Windows.Documents.Paragraph"></see>, which contains a single <see cref="T:System.Windows.Documents.Run"></see> which contains no text.</returns> /// <exception cref="T:System.ArgumentException">Raised if an attempt is made to set this property to a <see cref="T:System.Windows.Documents.FlowDocument"></see> that represents the contents of another <see cref="T:System.Windows.Controls.RichTextBox"></see>.</exception> /// <exception cref="T:System.ArgumentNullException">Raised if an attempt is made to set this property to null.</exception> /// <exception cref="T:System.InvalidOperationException">Raised if this property is set while a change block has been activated.</exception> public new FlowDocument Document { get { return (FlowDocument)GetValue(DocumentProperty); } set { SetValue(DocumentProperty, value); } } } Thank fro help and advice. Qucik example: Child window with .NET richTextBox <Window x:Class="WpfApplication2.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <Grid> <RichTextBox Background="Green" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" FontSize="13" Margin="4,4,4,4" Grid.Row="0"/> </Grid> </Window> This window I open from parent window: var w = new Window1(); w.Show(); Then close this window, check with memory profiler and it memory doesn’t exist any object of window1 - richTextBox. It’s Ok. But then I try bindable richTextBox: Child window 2: <Window x:Class="WpfApplication2.Window2" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Controls="clr-namespace:WpfApplication2.Controls" Title="Window2" Height="300" Width="300"> <Grid> <Controls:BindableRichTextBox Background="Red" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" FontSize="13" Margin="4,4,4,4" Grid.Row="0" /> </Grid> </Window> Open child window 2, close this child window and in memory are still alive object of this child window also bindable richTextBox object.

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  • Will this RAID5 setup work (3TB Seagate Barracudas + Adaptec RAID 6405)?

    - by Slayer537
    As the title states, will this RAID combo work, and if not what needs to be changed? Overall opinions would be most helpful. I currently run a small file server of about 5TB or so. I keep outgrowing my needs and need to build a RAID setup that will allow me to expand as needed. I am new to RAID setups, especially one of the scale I have currently planned out, but I have being doing some research for the past couple of weeks and have come up with a build. Ideally, I'd have the setup completely built, but I'd like to keep the total cost around $1k and can't afford to go above $1.5k, so unfortunately that's not an option. 2 of my current drives are WD Caviar Blacks 2TB; however, I have recently learned that due to the lack of TLER those drives are awful for any RAID setup other than 0 or 1. That being said, my third drive is a Seagate Barracuda 3TB (ST300DM001) and I have found a RAID controller that states it supports it, so I'd like to use this same type of drive, if possible. Have any of you had any experience using this drive or a similar one in a RAID5 configuration? The manufacturer states that it supports it, but knowing that it is not an enterprise drive, I am slightly concerned that it could drop out of the array. I would just go with enterprise drives, but those are about double in cost... Parts list: Storage rack: http://www.ebay.com/itm/SGI-3U-Media-Storage-Server-16-Hard-Drive-Bay-SATA-SAS-Expander-Omnistor-SE3016-/140735776937?pt=LH_DefaultDomain_0&hash=item20c48188a9 3 more HDs (for now..): http://www.amazon.com/Seagate-Barracuda-3-5-Inch-Internal-ST3000DM001/dp/B005T3GRLY/ref=dp_return_2?ie=UTF8&n=172282&s=electronics Adaptec RAID 6405: http://www.newegg.com/Product/Product.aspx?Item=N82E16816103224 here's a link to the compatibility sheet if that helps: http://download.adaptec.com/pdfs/compatibility_report/arc-sas_cr_03-27-12_series6.pdf SAS expander cable: http://www.pc-pitstop.com/sas_cables_adapters/8887-2M.asp My plan is to install the RAID card in my computer and then route the SAS cable to the rack. Setup a RAID5 on 3 drives, transfer my data over from my other drive, and then add that drive to the array. Eventually, I'd like to get a 2U unit and run the file server on that and move the RAID card over to there, but that will have to happen later on. Side note: The computer the card would be going into will be running Windows 7 Pro with 24GB of DDR3-1600 and an i7-930.

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  • Many to Many Logic in ASP.NET MVC

    - by Jonathan Stowell
    Hi All, I will restrict this to the three tables I am trying to work with Problem, Communications, and ProbComms. The scenario is that a Student may have many Problems concurrently which may affect their studies. Lecturers may have future communications with a student after an initial problem is logged, however as a Student may have multiple Problems the Lecturer may decide that the discussion they had is related to more than one Problem. Here is a screenshot of the LINQ representation of my DB: LINQ Screenshot At the moment in my StudentController I have a StudentFormViewModel Class: // //ViewModel Class public class StudentFormViewModel { IProbCommRepository probCommRepository; // Properties public Student Student { get; private set; } public IEnumerable<ProbComm> ProbComm { get; private set; } // // Dependency Injection enabled constructors public StudentFormViewModel(Student student, IEnumerable<ProbComm> probComm) : this(new ProbCommRepository()) { this.Student = student; this.ProbComm = probComm; } public StudentFormViewModel(IProbCommRepository pRepository) { probCommRepository = pRepository; } } When I go to the Students Detail Page this runs: public ActionResult Details(string id) { StudentFormViewModel viewdata = new StudentFormViewModel(studentRepository.GetStudent(id), probCommRepository.FindAllProblemComms(id)); if (viewdata == null) return View("NotFound"); else return View(viewdata); } The GetStudent works fine and returns an instance of the student to output on the page, below the student I output all problems logged against them, but underneath these problems I want to show the communications related to the Problem. The LINQ I am using for ProbComms is This is located in the Model class ProbCommRepository, and accessed via a IProbCommRepository interface: public IQueryable<ProbComm> FindAllProblemComms(string studentEmail) { return (from p in db.ProbComms where p.Problem.StudentEmail.Equals(studentEmail) orderby p.Problem.ProblemDateTime select p); } However for example if I have this data in the ProbComms table: ProblemID CommunicationID 1 1 1 2 The query returns two rows so I assume I somehow have to groupby Problem or ProblemID but I am not too sure how to do this with the way I have built things as the return type has to be ProbComm for the query as thats what Model class its located in. When it comes to the view the Details.aspx calls two partial views each passing the relevant view data through, StudentDetails works fine page: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MitigatingCircumstances.Controllers.StudentFormViewModel>" %> <% Html.RenderPartial("StudentDetails", this.ViewData.Model.Student); %> <% Html.RenderPartial("StudentProblems", this.ViewData.Model.ProbComm); %> StudentProblems uses a foreach loop to loop through records in the Model and I am trying another foreach loop to output the communication details: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<MitigatingCircumstances.Models.ProbComm>>" %> <script type="text/javascript" language="javascript"> $(document).ready(function() { $("DIV.ContainerPanel > DIV.collapsePanelHeader > DIV.ArrowExpand").toggle( function() { $(this).parent().next("div.Content").show("slow"); $(this).attr("class", "ArrowClose"); }, function() { $(this).parent().next("div.Content").hide("slow"); $(this).attr("class", "ArrowExpand"); }); }); </script> <div class="studentProblems"> <% var i = 0; foreach (var item in Model) { %> <div id="ContainerPanel<%= i = i + 1 %>" class="ContainerPanel"> <div id="header<%= i = i + 1 %>" class="collapsePanelHeader"> <div id="dvHeaderText<%= i = i + 1 %>" class="HeaderContent"><%= Html.Encode(String.Format("{0:dd/MM/yyyy}", item.Problem.ProblemDateTime))%></div> <div id="dvArrow<%= i = i + 1 %>" class="ArrowExpand"></div> </div> <div id="dvContent<%= i = i + 1 %>" class="Content" style="display: none"> <p> Type: <%= Html.Encode(item.Problem.CommunicationType.TypeName) %> </p> <p> Problem Outline: <%= Html.Encode(item.Problem.ProblemOutline)%> </p> <p> Mitigating Circumstance Form: <%= Html.Encode(item.Problem.MCF)%> </p> <p> Mitigating Circumstance Level: <%= Html.Encode(item.Problem.MitigatingCircumstanceLevel.MCLevel)%> </p> <p> Absent From: <%= Html.Encode(String.Format("{0:g}", item.Problem.AbsentFrom))%> </p> <p> Absent Until: <%= Html.Encode(String.Format("{0:g}", item.Problem.AbsentUntil))%> </p> <p> Requested Follow Up: <%= Html.Encode(String.Format("{0:g}", item.Problem.RequestedFollowUp))%> </p> <p>Problem Communications</p> <% foreach (var comm in Model) { %> <p> <% if (item.Problem.ProblemID == comm.ProblemID) { %> <%= Html.Encode(comm.ProblemCommunication.CommunicationOutline)%> <% } %> </p> <% } %> </div> </div> <br /> <% } %> </div> The issue is that using the example data before the Model has two records for the same problem as there are two communications for that problem, therefore duplicating the output. Any help with this would be gratefully appreciated. Thanks, Jon

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  • DSL Modem with Wireless Router

    - by David
    I have a D-Link WBR-1310 wireless router and a TP-Link TD-8616 DSL modem. My old DSL modem died recently and I got the TP-Link as a replacement. With my old DSL modem, I plugged it into the WAN port on my D-Link and I could reach the internet through wireless and through the network. However, when I plugged the new TP-Link into the WAN port, I was not able to get any internet connectivity (either on the network ports or through wireless). So I plugged my labtop directly into the TP-Link DSL modem and I was able to get internet connectivity. I'm trying to figure out why my labtop can see the internet connection, but not the D-Link router. I think that the problem is due to the IP networking. My D-Link was originally set to have IP address 192.168.1.1. According to the documentation for the TP-Link DSL modem, it uses 192.168.1.1 as its IP address. I do not believe that my old DSL modem had an IP address. I logged into my D-Link router and changed its IP address to 192.168.1.2 and restarted it. Unfortunately, I still could not see the internet from my wireless devices. I've read a few forum postings which implied that I needed to setup a "bridge" between the two networks. Does that sound correct? Why didn't my old DSL modem require a bridge? I read pg. 12-13 of my D-Link's manual and they suggest that I need to disable UPnP, DHCP, and then plug the DSL modem into one of the LAN ports on my router. I'm concerned about doing this since I don't think that the firewall will work if I plug my DSL modem into one of the LAN ports. I also have a home NAS on my network and I wouldn't want that to be available over the internet. Does anyone have any advice about how I can get my TPLink DSL modem to work with my D-Link router? Thanks!

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  • Bidirectional real-time sync of large file tree between two distant linux servers

    - by dlo
    By large file tree I mean about 200k files, and growing all the time. A relatively small number of files are being changed in any given hour though. By bidirectional I mean that changes may occur on either server and need to be pushed to the other, so rsync doesn't seem appropriate. By distant I mean that the servers are both in data centers, but geographically remote from each other. Currently there are only 2 servers, but that may expand over time. By real-time, it's ok for there to be a little latency between syncing, but running a cron every 1-2 minutes doesn't seem right, since a very small fraction of files may change in any given hour, let alone minute. EDIT: This is running on VPS's so I might be limited on the kinds of kernel-level stuff I can do. Also, the VPS's are not resource-rich, so I'd shy away from solutions that require lots of ram (like Gluster?). What's the best / most "accepted" approach to get this done? This seems like it would be a common need, but I haven't been able to find a generally accepted approach yet, which was surprising. (I'm seeking the safety of the masses. :) I've come across lsyncd to trigger a sync at the filesystem change level. That seems clever though not super common, and I'm a bit confused by the various lsyncd approaches. There's just using lsyncd with rsync, but it seems this could be fragile for bidirectionality since rsync doesn't have a notion of memory (eg- to know whether a deleted file on A should be deleted on B or whether it's a new file on B that should be copied to A). lipsync appears to be just a lsyncd+rsync implementation, right? Then there's using lsyncd with csync2, like this: http://www.axivo.com/community/threads/lightning-fast-synchronization-with-csync2-and-lsyncd.121/ ... I'm leaning towards this approach, but csync2 is a little quirky, though I did do a successful test of it. I'm mostly concerned that I haven't been able to find a lot of community confirmation of this method. People on here seem to like Unison a lot, but it seems that it is no longer under active development and it's not clear that it has an automatic trigger like lsyncd. I've seen Gluster mentioned, but maybe overkill for what I need? UPDATE: fyi- I ended up going with the original solution I mentioned: lsyncd+csync2. It seems to work quite well, and I like the architectural approach of having the servers be very loosely joined, so that each server can operate indefinitely on its own regardless of the link quality between them.

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  • How to reinstall Mac OS X on OS X/Linux dual-boot system?

    - by strangeronyourtrain
    My setup: I have a MacBook Pro 5,5 with a Mac OS X Snow Leopard partition and a Linux partition. I use rEFIt to boot into Linux. I didn't use Boot Camp when I originally installed Linux; instead, I manually created the partition (with either Disk Utility in OS X or Gparted on a Linux live CD--I don't recall which one) and then installed Linux on it from a live CD. The problem: My OS X partition is corrupt, and I need to reinstall Snow Leopard. Since I installed rEFIt from within OS X, I'm concerned that wiping the OS X partition will prevent me from booting into my Linux partition. How can I do this without losing access to my Linux partition? Is it possible to install Snow Leopard on the partition I reserved for it, or will it automatically overwrite the entire drive? And if I do the fresh OS X install and then install rEFIt again, will it automatically recognize my Linux partition? Thanks for any tips! Specs: MacBook Pro 5,5 (Mid-2009); Snow Leopard 10.6.7/64-bit Sabayon Linux, 2.6.36 kernel EDIT/UPDATE: Thanks, but the situation has taken a more complicated turn: I tried to reinstall Snow Leopard from the DVD, but it refused to install onto my Mac partition, claiming: "The disk cannot be used to start up your computer." Disk Utility wouldn't let me resize the partition or create a new one, and it doesn't see my Linux partition. It only displays the two partitions "Macintosh HD" and Linux Swap. I can, however, see all the partitions from Linux. This is the partition table as shown in Gparted: And the output of "fdisk -l" is: WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sda: 250.1 GB, 250059350016 bytes 255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sda1 1 409639 204819+ ee GPT /dev/sda2 409640 349590464 174590412+ af HFS / HFS+ /dev/sda3 483122745 488392064 2634660 82 Linux swap / Solaris /dev/sda4 * 349590465 483122744 66766140 83 Linux Partition table entries are not in disk order I wonder if this is because I originally partitioned my disk with Gparted instead of OS X's Disk Utility (at this point, I don't recall whether I used Gparted or Disk Utility). In any case, it doesn't seem safe to do any reformatting with Disk Utility now, as I'm afraid it will wipe sda2 ("Macintosh HD") as well as sda4 (my Linux partition). So... I'm hoping to find a solution that doesn't involve wiping my entire hard disk. Would it be safe/possible to use Gparted to erase sda2 ("Macintosh HD") and then use the Snow Leopard DVD to install OS X onto [I]just[/I] sda2 without touching the other partitions? Thanks for any insight!

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  • The Cindy Shearin Group: New Scam Targets Renters in the Area

    - by user226089
    MONROE - Craigslist is a popular site when trying to find that perfect deal on a rental home or apartment. Experts warn some of these rental ads aren't what they seem. We decided to take a look. On our Craigslist search we found this house for rent. The problem is this home’s not for rent - it's for sale. “I think it’s a huge deal,” said Shane Wooten, the realtor for this home in Monroe. His properties have become the target of a common scam, aimed at taking your money. "It looks like they're trying to scam them out of their deposit and first months rent," adds Wooten. He says scammers copy and paste the sale ad's from legitimate realtor sites to Craigslist as rental ads. "I can usually tell when one hits craigslist because I’ll usually get 20 to 30 phone calls that day." They then pretend to be out of town on business or personal matters, and give only an email address as a point of contact. Usually they'll ask for money up front on a deal too good to miss. "You'll have a house that's supposed to rent for $950-1000 a month, and they'll have it renting for $600 a month,” says Wooten During our conversation, he shows us text messages from one scammer who says he'll mail the keys to this house if Wooten wires money for a deposit and first months rent. Jo Ann Deal of the Better Business Bureau says scammers are getting better at making themselves out to be realtors. "We’re really concerned for our real estate agents with this scam," says Deal. She says that realtors have to be more on top of their vacant homes in order to protect their businesses. So how can you tell if the house you want is really for rent? She says if the home owner lives out of the country, can't meet face to face or asks for a payment through a money wire it's probably a scam. “There are some catch-lines you watch for,” says Deal. “If the marketing is really good but there's no phone number, no physical address and they will communicate with you only by email and you can do it today, then it's probably a scam." You should always report fishy ad's to Craigslist or the BBB and never send money through a wire transfer.

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  • Many to Many with LINQ-To-Sql and ASP.NET MVC

    - by Jonathan Stowell
    Hi All, I will restrict this to the three tables I am trying to work with Problem, Communications, and ProbComms. The scenario is that a Student may have many Problems concurrently which may affect their studies. Lecturers may have future communications with a student after an initial problem is logged, however as a Student may have multiple Problems the Lecturer may decide that the discussion they had is related to more than one Problem. Here is a screenshot of the LINQ-To-Sql representation of my DB: LINQ-To-Sql Screenshot At the moment in my StudentController I have a StudentFormViewModel Class: // //ViewModel Class public class StudentFormViewModel { IProbCommRepository probCommRepository; // Properties public Student Student { get; private set; } public IEnumerable<ProbComm> ProbComm { get; private set; } // // Dependency Injection enabled constructors public StudentFormViewModel(Student student, IEnumerable<ProbComm> probComm) : this(new ProbCommRepository()) { this.Student = student; this.ProbComm = probComm; } public StudentFormViewModel(IProbCommRepository pRepository) { probCommRepository = pRepository; } } When I go to the Students Detail Page this runs: public ActionResult Details(string id) { StudentFormViewModel viewdata = new StudentFormViewModel(studentRepository.GetStudent(id), probCommRepository.FindAllProblemComms(id)); if (viewdata == null) return View("NotFound"); else return View(viewdata); } The GetStudent works fine and returns an instance of the student to output on the page, below the student I output all problems logged against them, but underneath these problems I want to show the communications related to the Problem. The LINQ I am using for ProbComms is This is located in the Model class ProbCommRepository, and accessed via a IProbCommRepository interface: public IQueryable<ProbComm> FindAllProblemComms(string studentEmail) { return (from p in db.ProbComms where p.Problem.StudentEmail.Equals(studentEmail) orderby p.Problem.ProblemDateTime select p); } However for example if I have this data in the ProbComms table: ProblemID CommunicationID 1 1 1 2 The query returns two rows so I assume I somehow have to groupby Problem or ProblemID but I am not too sure how to do this with the way I have built things as the return type has to be ProbComm for the query as thats what Model class its located in. When it comes to the view the Details.aspx calls two partial views each passing the relevant view data through, StudentDetails works fine page: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MitigatingCircumstances.Controllers.StudentFormViewModel>" %> <% Html.RenderPartial("StudentDetails", this.ViewData.Model.Student); %> <% Html.RenderPartial("StudentProblems", this.ViewData.Model.ProbComm); %> StudentProblems uses a foreach loop to loop through records in the Model and I am trying another foreach loop to output the communication details: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<MitigatingCircumstances.Models.ProbComm>>" %> <script type="text/javascript" language="javascript"> $(document).ready(function() { $("DIV.ContainerPanel > DIV.collapsePanelHeader > DIV.ArrowExpand").toggle( function() { $(this).parent().next("div.Content").show("slow"); $(this).attr("class", "ArrowClose"); }, function() { $(this).parent().next("div.Content").hide("slow"); $(this).attr("class", "ArrowExpand"); }); }); </script> <div class="studentProblems"> <% var i = 0; foreach (var item in Model) { %> <div id="ContainerPanel<%= i = i + 1 %>" class="ContainerPanel"> <div id="header<%= i = i + 1 %>" class="collapsePanelHeader"> <div id="dvHeaderText<%= i = i + 1 %>" class="HeaderContent"><%= Html.Encode(String.Format("{0:dd/MM/yyyy}", item.Problem.ProblemDateTime))%></div> <div id="dvArrow<%= i = i + 1 %>" class="ArrowExpand"></div> </div> <div id="dvContent<%= i = i + 1 %>" class="Content" style="display: none"> <p> Type: <%= Html.Encode(item.Problem.CommunicationType.TypeName) %> </p> <p> Problem Outline: <%= Html.Encode(item.Problem.ProblemOutline)%> </p> <p> Mitigating Circumstance Form: <%= Html.Encode(item.Problem.MCF)%> </p> <p> Mitigating Circumstance Level: <%= Html.Encode(item.Problem.MitigatingCircumstanceLevel.MCLevel)%> </p> <p> Absent From: <%= Html.Encode(String.Format("{0:g}", item.Problem.AbsentFrom))%> </p> <p> Absent Until: <%= Html.Encode(String.Format("{0:g}", item.Problem.AbsentUntil))%> </p> <p> Requested Follow Up: <%= Html.Encode(String.Format("{0:g}", item.Problem.RequestedFollowUp))%> </p> <p>Problem Communications</p> <% foreach (var comm in Model) { %> <p> <% if (item.Problem.ProblemID == comm.ProblemID) { %> <%= Html.Encode(comm.ProblemCommunication.CommunicationOutline)%> <% } %> </p> <% } %> </div> </div> <br /> <% } %> </div> The issue is that using the example data before the Model has two records for the same problem as there are two communications for that problem, therefore duplicating the output. Any help with this would be gratefully appreciated. Thanks, Jon

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  • KeePass justification

    - by Jeff Walker
    I work at a place that tries to take security seriously, but sadly, they often fail. Currently, one of the major ways they fail is password management. I personally have about 20 accounts (my personal user id on lots of machines). For shared "system" accounts, there are about 45 per environment; development, test, and production. I have access to 2 of those, so my personal total is somewhere around 115 accounts. Passwords have to be at least 15 characters with some extensive but standard complexity constraints, and have to be changed every 60 days or so (system accounts every year). They also should not be the same for different accounts, but that isn't enforced. Think DoD-type standards. There is no way to remember and keep up with this. It just isn't humanly possible, as far as I'm concerned. This might be a good justification of a centralized account management system, a la LDAP or ActiveDirectory, but that is a totally different battle. Currently the solution is an Excel spreadsheet. They use Excel to put a password on it, and then most people make a copy and remove the password. This makes my stomach turn. I use KeePass for this problem and it manages all of my account very well. I like the features like auto-typing, grouping, plugins, password generation, etc. It uses AES-256 encryption via the .Net framework, and while not FIPS compliant, it has a very good reputation. The only problem is that they are also very careful about using randomly downloaded software. So we have to justify every piece of software on our workstations. I have been told that they really don't want me to use this, be cause of the "sensitive nature" of storing passwords. sigh My justification has to be "VERY VERY strong". I have been tasked with writing a justification for KeePass, but as I am lazy, I would like any input that I can get from the community. What do you recommend? Is there something out there that is better or more respected than KeePass? Is there any security experts saying interesting things on this topic? Anything will help at this point. Thanks.

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  • Convert flyout menu to respond onclick vs mouseover

    - by Scott B
    The code below creates a nifty flyout menu action on a nested list item sequence. The client has called and wants the change the default behavior in which the flyouts are triggered by mouseover, so that you have to click to trigger a flyout. Ideally, I would just like to modify this code so that you click on a small icon (plus/minus) that sits to the right of the menu item if it has child menus. Can someone give me a bit of guidance on what bits I'd need to change to accomplish this? /* a few sniffs to circumvent known browser bugs */ var sUserAgent = navigator.userAgent.toLowerCase(); var isIE=document.all?true:false; var isNS4=document.layers?true:false; var isOp=(sUserAgent.indexOf('opera')!=-1)?true:false; var isMac=(sUserAgent.indexOf('mac')!=-1)?true:false; var isMoz=(sUserAgent.indexOf('mozilla/5')!=-1&&sUserAgent.indexOf('opera')==-1&&sUserAgent.indexOf('msie')==-1)?true:false; var isNS6=(sUserAgent.indexOf('netscape6')!=-1&&sUserAgent.indexOf('opera')==-1&&sUserAgent.indexOf('msie')==-1)?true:false; var dom=document.getElementById?true:false; /* sets time until menus disappear in milliseconds */ var iMenuTimeout=1500; var aMenus=new Array; var oMenuTimeout; var iMainMenusLength=0; /* the following boolean controls the z-index property if needed */ /* if is only necessary if you have multiple mainMenus in one file that are overlapping */ /* set bSetZIndeces to true (either here or in the HTML) and the main menus will have a z-index set in descending order so that preceding ones can overlap */ /* the integer iStartZIndexAt controls z-index of the first main menu */ var bSetZIndeces=true; var iStartZIndexAt=1000; var aMainMenus=new Array; /* load up the submenus */ function loadMenus(){ if(!dom)return; var aLists=document.getElementsByTagName('ul'); for(var i=0;i<aLists.length;i++){ if(aLists[i].className=='navMenu')aMenus[aMenus.length]=aLists[i]; } var aAnchors=document.getElementsByTagName('a'); var aItems = new Array; for(var i=0;i<aAnchors.length;i++){ // if(aAnchors[i].className=='navItem')aItems[aItems.length] = aAnchors[i]; aItems[aItems.length] = aAnchors[i]; } var sMenuId=null; var oParentMenu=null; var aAllElements=document.body.getElementsByTagName("*"); if(isIE)aAllElements=document.body.all; /* loop through navItem and navMenus and dynamically assign their IDs */ /* each relies on it's parent's ID being set before it */ for(var i=0;i<aAllElements.length;i++){ if(aAllElements[i].className.indexOf('x8menus')!=-1){ /* load up main menus collection */ if(bSetZIndeces)aMainMenus[aMainMenus.length]=aAllElements[i]; } // if(aAllElements[i].className=='navItem'){ if(aAllElements[i].tagName=='A'){ oParentMenu = aAllElements[i].parentNode.parentNode; if(!oParentMenu.childMenus) oParentMenu.childMenus = new Array; oParentMenu.childMenus[oParentMenu.childMenus.length]=aAllElements[i]; if(aAllElements[i].id==''){ if(oParentMenu.className=='x8menus'){ aAllElements[i].id='navItem_'+iMainMenusLength; //alert(aAllElements[i].id); iMainMenusLength++; }else{ aAllElements[i].id=oParentMenu.id.replace('Menu','Item')+'.'+oParentMenu.childMenus.length; } } } else if(aAllElements[i].className=='navMenu'){ oParentItem = aAllElements[i].parentNode.firstChild; aAllElements[i].id = oParentItem.id.replace('Item','Menu'); } } /* dynamically set z-indeces of main menus so they won't underlap */ for(var i=aMainMenus.length-1;i>=0;i--){ aMainMenus[i].style.zIndex=iStartZIndexAt-i; } /* set menu item properties */ for(var i=0;i<aItems.length;i++){ sMenuId=aItems[i].id; sMenuId='navMenu_'+sMenuId.substring(8,sMenuId.lastIndexOf('.')); /* assign event handlers */ /* eval() used here to avoid syntax errors for function literals in Netscape 3 */ eval('aItems[i].onmouseover=function(){modClass(true,this,"activeItem");window.clearTimeout(oMenuTimeout);showMenu("'+sMenuId+'");};'); eval('aItems[i].onmouseout=function(){modClass(false,this,"activeItem");window.clearTimeout(oMenuTimeout);oMenuTimeout=window.setTimeout("hideMenu(\'all\')",iMenuTimeout);}'); eval('aItems[i].onfocus=function(){this.onmouseover();}'); eval('aItems[i].onblur=function(){this.onmouseout();}'); //aItems[i].addEventListener("keydown",function(){keyNav(this,event);},false); } var sCatId=0; var oItem; for(var i=0;i<aMenus.length;i++){ /* assign event handlers */ /* eval() used here to avoid syntax errors for function literals in Netscape 3 */ eval('aMenus[i].onmouseover=function(){window.clearTimeout(oMenuTimeout);}'); eval('aMenus[i].onmouseout=function(){window.clearTimeout(oMenuTimeout);oMenuTimeout=window.setTimeout("hideMenu(\'all\')",iMenuTimeout);}'); sCatId=aMenus[i].id; sCatId=sCatId.substring(8,sCatId.length); oItem=document.getElementById('navItem_'+sCatId); if(oItem){ if(!isOp && !(isMac && isIE) && oItem.parentNode)modClass(true,oItem.parentNode,"hasSubMenu"); else modClass(true,oItem,"hasSubMenu"); /* assign event handlers */ eval('oItem.onmouseover=function(){window.clearTimeout(oMenuTimeout);showMenu("navMenu_'+sCatId+'");}'); eval('oItem.onmouseout=function(){window.clearTimeout(oMenuTimeout);oMenuTimeout=window.clearTimeout(oMenuTimeout);oMenuTimeout=window.setTimeout(\'hideMenu("navMenu_'+sCatId+'")\',iMenuTimeout);}'); eval('oItem.onfocus=function(){window.clearTimeout(oMenuTimeout);showMenu("navMenu_'+sCatId+'");}'); eval('oItem.onblur=function(){window.clearTimeout(oMenuTimeout);oMenuTimeout=window.clearTimeout(oMenuTimeout);oMenuTimeout=window.setTimeout(\'hideMenu("navMenu_'+sCatId+'")\',iMenuTimeout);}'); //oItem.addEventListener("keydown",function(){keyNav(this,event);},false); } } } /* this will append the loadMenus function to any previously assigned window.onload event */ /* if you reassign this onload event, you'll need to include this or execute it after all the menus are loaded */ function newOnload(){ if(typeof previousOnload=='function')previousOnload(); loadMenus(); } var previousOnload; if(window.onload!=null)previousOnload=window.onload; window.onload=newOnload; /* show menu and hide all others except ancestors of the current menu */ function showMenu(sWhich){ var oWhich=document.getElementById(sWhich); if(!oWhich){ hideMenu('all'); return; } var aRootMenus=new Array; aRootMenus[0]=sWhich var sCurrentRoot=sWhich; var bHasParentMenu=false; if(sCurrentRoot.indexOf('.')!=-1){ bHasParentMenu=true; } /* make array of this menu and ancestors so we know which to leave exposed */ /* ex. from ID string "navMenu_12.3.7.4", extracts menu levels ["12.3.7.4", "12.3.7", "12.3", "12"] */ while(bHasParentMenu){ if(sCurrentRoot.indexOf('.')==-1)bHasParentMenu=false; aRootMenus[aRootMenus.length]=sCurrentRoot; sCurrentRoot=sCurrentRoot.substring(0,sCurrentRoot.lastIndexOf('.')); } for(var i=0;i<aMenus.length;i++){ var bIsRoot=false; for(var j=0;j<aRootMenus.length;j++){ var oThisItem=document.getElementById(aMenus[i].id.replace('navMenu_','navItem_')); if(aMenus[i].id==aRootMenus[j])bIsRoot=true; } if(bIsRoot && oThisItem)modClass(true,oThisItem,'hasSubMenuActive'); else modClass(false,oThisItem,'hasSubMenuActive'); if(!bIsRoot && aMenus[i].id!=sWhich)modClass(false,aMenus[i],'showMenu'); } modClass(true,oWhich,'showMenu'); var oItem=document.getElementById(sWhich.replace('navMenu_','navItem_')); if(oItem)modClass(true,oItem,'hasSubMenuActive'); } function hideMenu(sWhich){ if(sWhich=='all'){ /* loop backwards b/c WinIE6 has a bug with hiding display of an element when it's parent is already hidden */ for(var i=aMenus.length-1;i>=0;i--){ var oThisItem=document.getElementById(aMenus[i].id.replace('navMenu_','navItem_')); if(oThisItem)modClass(false,oThisItem,'hasSubMenuActive'); modClass(false,aMenus[i],'showMenu'); } }else{ var oWhich=document.getElementById(sWhich); if(oWhich)modClass(false,oWhich,'showMenu'); var oThisItem=document.getElementById(sWhich.replace('navMenu_','navItem_')); if(oThisItem)modClass(false,oThisItem,'hasSubMenuActive'); } } /* add or remove element className */ function modClass(bAdd,oElement,sClassName){ if(bAdd){/* add class */ if(oElement.className.indexOf(sClassName)==-1)oElement.className+=' '+sClassName; }else{/* remove class */ if(oElement.className.indexOf(sClassName)!=-1){ if(oElement.className.indexOf(' '+sClassName)!=-1)oElement.className=oElement.className.replace(' '+sClassName,''); else oElement.className=oElement.className.replace(sClassName,''); } } return oElement.className; /* return new className */ } //document.body.addEventListener("keydown",function(){keyNav(event);},true); function setBubble(oEvent){ oEvent.bubbles = true; } function keyNav(oElement,oEvent){ alert(oEvent.keyCode); window.status=oEvent.keyCode; return false; }

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  • What "pieces" are needed in order to set up a cluster of physical servers?

    - by Chris Dutrow
    Background: Currently, we use Rackspace cloud servers. We have no intention to stop using them, but would like to look into setting up a cluster of physical servers (probably desktop computers in the $400 range with 8gb memory each) to offset some of our load and work as a secondary, more powerful, less reliable system. To put things in perspective, we can buy comparable desktop computers for the same price as we pay in one month to rent them on Rackspace Cloud. I understand that this is generally a dumb idea. However, in this particular instance, the server cluster is needed for its computation power. It is not mission-critical, it does not host a consumer-facing website, and if it goes down for a day or two, its not really a problem. Currently, we have access to business class verizon fios. If I understand correctly, we can get at least 25 dedicated IP addresses with this service, this should be enough. Requirements: Each server runs Linux Centos 6.3 Some of the servers run Python and execute processes from a task queue (Redis or RabbitMQ) Some of the servers are capable of serving static files and Python driven REST APIs Some of the servers host a Cassandra database cluster One or more of the servers are a Redis database servers One or more of the servers are PostgreSQL servers Questions: What kind of router or switch is needed? We would like the computers to be able to communicate effectively with each other via internal IP addresses. This is especially important for communicating with servers hosting Redis that need to be able to respond to requests very quickly. Are there special switches or routers that need to be used to connect the servers together? Are Desktop computers ok for this? We have found that we are mostly RAM-bottle necked, I understand that some servers have highly superior CPUs, but I'm not sure we need CPU power as much as we need RAM, which is cheap in Desktop computers. Will we have problems with the WIFI cards in the desktops or any other unexpected hardware limitation? What tools should be used to "image" the servers. For example, when we get an installation right for a Redis server or Cassandra node, are there tools that come with Linux Centos 6.3 to image the server to a USB drive or something like that? Or do we need to use some other software for this? What other things are we missing that we should be concerned about? Thanks so much!

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  • Performance of ClearCase servers on VMs?

    - by Garen
    Where I work, we are in need of upgrading our ClearCase servers and it's been proposed that we move them into a new (yet-to-be-deployed) VMmare system. In the past I've not noticed a significant problem with performance with most applications when running in VMs, but given that ClearCase "speed" (i.e. dynamic-view response times) is so latency sensitive I am concerned that this will not be a good idea. VMWare has numerous white-papers detailing performance related issues based on network traffic patterns that re-inforces my hypothesis, but nothing particularly concrete for this particular use case that I can see. What I can find are various forum posts online, but which are somewhat dated, e.g.: ClearCase clients are supported on VMWare, but not for performance issues. I would never put a production server on VM. It will work but will be slower. The more complex the slower it gets. accessing or building from a local snapshot view will be the fastest, building in a remote VM stored dynamic view using clearmake will be painful..... VMWare is best used for test environments (via http://www.cmcrossroads.com/forums?func=view&catid=31&id=44094&limit=10&start=10) and: VMware + ClearCase = works but SLUGGISH!!!!!! (windows)(not for production environment) My company tried to mandate that all new apps or app upgrades needed to be on/moved VMware instances. The VMware instance could not handle the demands of ClearCase. (come to find out that I was sharing a box with a database server) Will you know what else would be on that box besides ClearCase? Karl (via http://www.cmcrossroads.com/forums?func=view&id=44094&catid=31) and: ... are still finding we can't get the performance using dynamic views to below 2.5 times that of a physical machine. Interestingly, speaking to a few people with much VMWare experience and indeed from running builds, we are finding that typically, VMWare doesn't take that much longer for most applications and about 10-20% longer has been quoted. (via http://www.cmcrossroads.com/forums?func=view&catid=31&id=44094&limit=10&start=10) Which brings me to the more direct question: Does anyone have any more recent experience with ClearCase servers on VMware (if not any specific, relevant performance advice)?

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  • Microphones not working on Apple macbook Air 1,1 (Early 2008) under Linux

    - by jj_p
    I'm running Linux on an mba. I can't make the microphones (neither external nor internal) work. I test using alsamixer and arecord -d 5 test-mic.waw together with aplay test-mic.waw It seems there is a problem with kernel trying to decipher Apple (intentionally) corrupted 'bios', in particular the mic pins are wrongly assigned. As far as we are concerned here, is there any difference between using EFI and BIOS-compatibility mode? (see https://wiki.archlinux.org/index.php/MacBook where they claim to have everything working out of the box on mba1,1) A nice proposal would be to compile the latest Linux kernel and run hda-jack-retask to find the right configuration (in the case of Realtek codec, the missing things I'm supposed to check are either some vendor-specific COEF verbs, EAPD or GPIO setup.), and then come up with a kernel patch to address the issue. Since I'm not that familiar with this last part of the story, can anyone help me through this process? Some useful data: The output from alsa script run as root http://www.alsa-project.org/db/?f=adae8ebee1007043fe83414ac4972319e02255fa The command hda-jack-sense-test -a (with external mic in) Pin 0x14 (Internal Speaker): present = No Pin 0x15 (Green HP Out): present = Yes Pin 0x16 (Not connected): present = No Pin 0x17 (Not connected): present = No Pin 0x18 (Not connected): present = No Pin 0x19 (Not connected): present = No Pin 0x1a (Not connected): present = No Pin 0x1b (Not connected): present = No Pin 0x1c (Not connected): present = No Pin 0x1d (Not connected): present = No Pin 0x1e (Not connected): present = No Pin 0x1f (Not connected): present = No Most likely the chip is Realtek ALC885 (compare also ALC889A) http://guide-images.ifixit.net/igi/bBTSqaeK5JpQ1AWe.large , although at the moment alsa reads it as ALC889A Takashi Iwai's tutorial https://www.kernel.org/doc/Documentation/sound/alsa/HD-Audio.txt Some people researched the original files from a running OS X installation on this same model (I think the relevant files are AppleHDA.kext/Contents/MacOS/AppleHDA AppleHDA.kext/Contents/PlugIns/AppleHDAHardwareConfigDriver.kext/Contents/Info.p????list AppleHDA.kext/Contents/Resources/layout12.xml.zlib AppleHDA.kext/Contents/Resources/Platforms.xml.zlib) http://www.insanelymac.com/forum/topic/220090-alc889a-pin-configuration/#entry1554954 Datasheet http://www.realtek.info/pdf/ALC885_1-1.pdf (from the same Realtek, one can also try to download Linux driver, but this is just taken from ALSA project, as stated in the readme file.) Compare with this Arch guy http://www.alsa-project.org/db/?f=3ca8243c0626844f0264a3faad0aa72018bc14f4 Here for the first time support to audio (except mics) for mba1,2 (which is morally the same as 1,1) is patched into the kernel http://www.alsa-project.org/pipermail/alsa-devel/2010-February/025511.html The same jack supposedly works both for HP and ext MIC, I think it's called TRRS, and it's the same as the one used e.g. for iphones This guy might have done a similar job, though to a more recent version and for sound globally, not just mics: http://blogs.aerys.in/jeanmarc-leroux/2013/09/15/fixing-2013-macbook-air-ubuntu-sound-issue/ (this is mirror to http://unix.stackexchange.com/questions/73044/microphones-not-working-on-apple-macbook-air-1-1-early-2008-under-linux )

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