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• SQLAuthority News – Great Time Spent at Great Indian Developers Summit 2014

  - by Pinal Dave

  The Great Indian Developer Conference (GIDS) is one of the most popular annual event held in Bangalore. This year GIDS is scheduled on April 22, 25. I will be presented total four sessions at this event and each session is very different from each other. Here are the details of four of my sessions, which I presented there. Pluralsight Shades This event was a great event and I had fantastic fun presenting a technology over here. I was indeed very excited that along with me, I had many of my friends presenting at the event as well. I want to thank all of you to attend my session and having standing room every single time. I have already sent resources in my newsletter. You can sign up for the newsletter over here. Indexing is an Art I was amazed with the crowd present in the sessions at GIDS. There was a great interest in the subject of SQL Server and Performance Tuning. Audience at GIDS I believe event like such provides a great platform to meet and share knowledge. Pinal at Pluralsight Booth Here are the abstract of the sessions which I had presented. They were recorded so at some point in time they will be available, but if you want the content of all the courses immediately, I suggest you check out my video courses on the same subject on Pluralsight. Indexes, the Unsung Hero Relevant Pluralsight Course Slow Running Queries are the most common problem that developers face while working with SQL Server. While it is easy to blame SQL Server for unsatisfactory performance, the issue often persists with the way queries have been written, and how Indexes has been set up. The session will focus on the ways of identifying problems that slow down SQL Server, and Indexing tricks to fix them. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. Indexes are the most crucial objects of the database. They are the first stop for any DBA and Developer when it is about performance tuning. There is a good side as well evil side to indexes. To master the art of performance tuning one has to understand the fundamentals of indexes and the best practices associated with the same. We will cover various aspects of Indexing such as Duplicate Index, Redundant Index, Missing Index as well as best practices around Indexes. SQL Server Performance Troubleshooting: Ancient Problems and Modern Solutions Relevant Pluralsight Course Many believe Performance Tuning and Troubleshooting is an art which has been lost in time. However, truth is that art has evolved with time and there are more tools and techniques to overcome ancient troublesome scenarios. There are three major resources that when bottlenecked creates performance problems: CPU, IO, and Memory. In this session we will focus on High CPU scenarios detection and their resolutions. If time permits we will cover other performance related tips and tricks. At the end of this session, attendees will have a clear idea as well as action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. We will discuss about performance tuning in this session with the help of Demos. Pinal Dave at GIDS MySQL Performance Tuning – Unexplored Territory Relevant Pluralsight Course Performance is one of the most essential aspects of any application. Everyone wants their server to perform optimally and at the best efficiency. However, not many people talk about MySQL and Performance Tuning as it is an extremely unexplored territory. In this session, we will talk about how we can tune MySQL Performance. We will also try and cover other performance related tips and tricks. At the end of this session, attendees will not only have a clear idea, but also carry home action items regarding what to do when facing any of the above resource intensive scenarios. Developers will walk out with scripts and knowledge that can be applied to their servers, immediately post the session. To master the art of performance tuning one has to understand the fundamentals of performance, tuning and the best practices associated with the same. You will also witness some impressive performance tuning demos in this session. Hidden Secrets and Gems of SQL Server We Bet You Never Knew Relevant Pluralsight Course SQL Trio Session! It really amazes us every time when someone says SQL Server is an easy tool to handle and work with. Microsoft has done an amazing work in making working with complex relational database a breeze for developers and administrators alike. Though it looks like child’s play for some, the realities are far away from this notion. The basics and fundamentals though are simple and uniform across databases, the behavior and understanding the nuts and bolts of SQL Server is something we need to master over a period of time. With a collective experience of more than 30+ years amongst the speakers on databases, we will try to take a unique tour of various aspects of SQL Server and bring to you life lessons learnt from working with SQL Server. We will share some of the trade secrets of performance, configuration, new features, tuning, behaviors, T-SQL practices, common pitfalls, productivity tips on tools and more. This is a highly demo filled session for practical use if you are a SQL Server developer or an Administrator. The speakers will be able to stump you and give you answers on almost everything inside the Relational database called SQL Server. I personally attended the session of Vinod Kumar, Balmukund Lakhani, Abhishek Kumar and my favorite Govind Kanshi. Summary If you have missed this event here are two action items 1) Sign up for Resource Newsletter 2) Watch my video courses on Pluralsight Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL Tagged: GIDS

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• Session Report - Modern Software Development Anti-Patterns

  - by Janice J. Heiss

  In this standing-room-only session, building upon his 2011 JavaOne Rock Star “Diabolical Developer” session, Martijn Verburg, this time along with Ben Evans, identified and explored common “anti-patterns” – ways of doing things that keep developers from doing their best work. They emphasized the importance of social interaction and team communication, along with identifying certain psychological pitfalls that lead developers astray. Their emphasis was less on technical coding errors and more how to function well and to keep one’s focus on what really matters. They are the authors of the highly regarded The Well-Grounded Java Developer and are both movers and shakers in the London JUG community and on the Java Community Process. The large room was packed as they gave a fast-moving, witty presentation with lots of laughs and personal anecdotes. Below are a few of the anti-patterns they discussed.Anti-Pattern One: Conference-Driven DeliveryThe theme here is the belief that “Real pros hack code and write their slides minutes before their talks.” Their response to this anti-pattern is an expression popular in the military – PPPPPP, which stands for, “Proper preparation prevents piss-poor performance.”“Communication is very important – probably more important than the code you write,” claimed Verburg. “The more you speak in front of large groups of people the easier it gets, but it’s always important to do dry runs, to present to smaller groups. And important to be members of user groups where you can give presentations. It’s a great place to practice speaking skills; to gain new skills; get new contacts, to network.”They encouraged attendees to record themselves and listen to themselves giving a presentation. They advised them to start with a spouse or friends if need be. Learning to communicate to a group, they argued, is essential to being a successful developer. The emphasis here is that software development is a team activity and good, clear, accessible communication is essential to the functioning of software teams. Anti-Pattern Two: Mortgage-Driven Development The main theme here was that, in a period of worldwide recession and economic stagnation, people are concerned about keeping their jobs. So there is a tendency for developers to treat knowledge as power and not share what they know about their systems with their colleagues, so when it comes time to fix a problem in production, they will be the only one who knows how to fix it – and will have made themselves an indispensable cog in a machine so you cannot be fired. So developers avoid documentation at all costs, or if documentation is required, put it on a USB chip and lock it in a lock box. As in the first anti-pattern, the idea here is that communicating well with your colleagues is essential and documentation is a key part of this. Social interactions are essential. Both Verburg and Evans insisted that increasingly, year by year, successful software development is more about communication than the technical aspects of the craft. Developers who understand this are the ones who will have the most success. Anti-Pattern Three: Distracted by Shiny – Always Use the Latest Technology to Stay AheadThe temptation here is to pick out some obscure framework, try a bit of Scala, HTML5, and Clojure, and always use the latest technology and upgrade to the latest point release of everything. Don’t worry if something works poorly because you are ahead of the curve. Verburg and Evans insisted that there need to be sound reasons for everything a developer does. Developers should not bring in something simply because for some reason they just feel like it or because it’s new. They recommended a site run by a developer named Matt Raible with excellent comparison spread sheets regarding Web frameworks and other apps. They praised it as a useful tool to help developers in their decision-making processes. They pointed out that good developers sometimes make bad choices out of boredom, to add shiny things to their CV, out of frustration with existing processes, or just from a lack of understanding. They pointed out that some code may stay in a business system for 15 or 20 years, but not all code is created equal and some may change after 3 or 6 months. Developers need to know where the code they are contributing fits in. What is its likely lifespan? Anti-Pattern Four: Design-Driven Design The anti-pattern: If you want to impress your colleagues and bosses, use design patents left, right, and center – MVC, Session Facades, SOA, etc. Or the UML modeling suite from IBM, back in the day… Generate super fast code. And the more jargon you can talk when in the vicinity of the manager the better.Verburg shared a true story about a time when he was interviewing a guy for a job and asked him what his previous work was. The interviewee said that he essentially took patterns and uses an approved book of Enterprise Architecture Patterns and applied them. Verburg was dumbstruck that someone could have a job in which they took patterns from a book and applied them. He pointed out that the idea that design is a separate activity is simply wrong. He repeated a saying that he uses, “You should pay your junior developers for the lines of code they write and the things they add; you should pay your senior developers for what they take away.”He explained that by encouraging people to take things away, the code base gets simpler and reflects the actual business use cases developers are trying to solve, as opposed to the framework that is being imposed. He told another true story about a project to decommission a very long system. 98% of the code was decommissioned and people got a nice bonus. But the 2% remained on the mainframe so the 98% reduction in code resulted in zero reduction in costs, because the entire mainframe was needed to run the 2% that was left. There is an incentive to get rid of source code and subsystems when they are no longer needed. The session continued with several more anti-patterns that were equally insightful.

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• Avoiding coupling

  - by Seralize

  It is also true that a system may become so coupled, where each class is dependent on other classes that depend on other classes, that it is no longer possible to make a change in one place without having a ripple effect and having to make subsequent changes in many places.[1] This is why using an interface or an abstract class can be valuable in any object-oriented software project. Quote from Wikipedia Starting from scratch I'm starting from scratch with a project that I recently finished because I found the code to be too tightly coupled and hard to refactor, even when using MVC. I will be using MVC on my new project aswell but want to try and avoid the pitfalls this time, hopefully with your help. Project summary My issue is that I really wish to keep the Controller as clean as possible, but it seems like I can't do this. The basic idea of the program is that the user picks wordlists which is sent to the game engine. It will pick random words from the lists until there are none left. Problem at hand My main problem is that the game will have 'modes', and need to check the input in different ways through a method called checkWord(), but exactly where to put this and how to abstract it properly is a challenge to me. I'm new to design patterns, so not sure whether there exist any might fit my problem. My own attempt at abstraction Here is what I've gotten so far after hours of 'refactoring' the design plans, and I know it's long, but it's the best I could do to try and give you an overview (Note: As this is the sketch, anything is subject to change, all help and advice is very welcome. Also note the marked coupling points): Wordlist class Wordlist { // Basic CRUD etc. here! // Other sample methods: public function wordlistCount($user_id) {} // Returns count of how many wordlists a user has public function getAll($user_id) {} // Returns all wordlists of a user } Word class Word { // Basic CRUD etc. here! // Other sample methods: public function wordCount($wordlist_id) {} // Returns count of words in a wordlist public function getAll($wordlist_id) {} // Returns all words from a wordlist public function getWordInfo($word_id) {} // Returns information about a word } Wordpicker class Wordpicker { // The class needs to know which words and wordlists to exclude protected $_used_words = array(); protected $_used_wordlists = array(); // Wordlists to pick words from protected $_wordlists = array(); /* Public Methods */ public function setWordlists($wordlists = array()) {} public function setUsedWords($used_words = array()) {} public function setUsedWordlists($used_wordlists = array()) {} public function getRandomWord() {} // COUPLING POINT! Will most likely need to communicate with both the Wordlist and Word classes /* Protected Methods */ protected function _checkAvailableWordlists() {} // COUPLING POINT! Might need to check if wordlists are deleted etc. protected function _checkAvailableWords() {} // COUPLING POINT! Method needs to get all words in a wordlist from the Word class } Game class Game { protected $_session_id; // The ID of a game session which gets stored in the database along with game details protected $_game_info = array(); // Game instantiation public function __construct($user_id) { if (! $this->_session_id = $this->_gameExists($user_id)) { // New game } else { // Resume game } } // This is the method I tried to make flexible by using abstract classes etc. // Does it even belong in this class at all? public function checkWord($answer, $native_word, $translation) {} // This method checks the answer against the native word / translation word, depending on game mode public function getGameInfo() {} // Returns information about a game session, or creates it if it does not exist public function deleteSession($session_id) {} // Deletes a game session from the database // Methods dealing with game session information protected function _gameExists($user_id) {} protected function _getProgress($session_id) {} protected function _updateProgress($game_info = array()) {} } The Game /* CONTROLLER */ /* "Guess the word" page */ // User input $game_type = $_POST['game_type']; // Chosen with radio buttons etc. $wordlists = $_POST['wordlists']; // Chosen with checkboxes etc. // Starts a new game or resumes one from the database $game = new Game($_SESSION['user_id']); $game_info = $game->getGameInfo(); // Instantiates a new Wordpicker $wordpicker = new Wordpicker(); $wordpicker->setWordlists((isset($game_info['wordlists'])) ? $game_info['wordlists'] : $wordlists); $wordpicker->setUsedWordlists((isset($game_info['used_wordlists'])) ? $game_info['used_wordlists'] : NULL); $wordpicker->setUsedWords((isset($game_info['used_words'])) ? $game_info['used_words'] : NULL); // Fetches an available word if (! $word_id = $wordpicker->getRandomWord()) { // No more words left - game over! $game->deleteSession($game_info['id']); redirect(); } else { // Presents word details to the user $word = new Word(); $word_info = $word->getWordInfo($word_id); } The Bit to Finish /* CONTROLLER */ /* "Check the answer" page */ // ?????????????????? ( http://pastebin.com/cc6MtLTR ) Make sure you toggle the 'Layout Width' to the right for a better view. Thanks in advance. Questions To which extent should objects be loosely coupled? If object A needs info from object B, how is it supposed to get this without losing too much cohesion? As suggested in the comments, models should hold all business logic. However, as objects should be independent, where to glue them together? Should the model contain some sort of "index" or "client" area which connects the dots? Edit: So basically what I should do for a start is to make a new model which I can more easily call with oneliners such as $model->doAction(); // Lots of code in here which uses classes! How about the method for checking words? Should it be it's own object? I'm not sure where I should put it as it's pretty much part of the 'game'. But on another hand, I could just leave out the 'abstraction and OOPness' and make it a method of the 'client model' which will be encapsulated from the controller anyway. Very unsure about this.

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• How to improve the builder pattern?

  - by tangens

  Motivation Recently I searched for a way to initialize a complex object without passing a lot of parameter to the constructor. I tried it with the builder pattern, but I don't like the fact, that I'm not able to check at compile time if I really set all needed values. Traditional builder pattern When I use the builder pattern to create my Complex object, the creation is more "typesafe", because it's easier to see what an argument is used for: new ComplexBuilder() .setFirst( "first" ) .setSecond( "second" ) .setThird( "third" ) ... .build(); But now I have the problem, that I can easily miss an important parameter. I can check for it inside the build() method, but that is only at runtime. At compile time there is nothing that warns me, if I missed something. Enhanced builder pattern Now my idea was to create a builder, that "reminds" me if I missed a needed parameter. My first try looks like this: public class Complex { private String m_first; private String m_second; private String m_third; private Complex() {} public static class ComplexBuilder { private Complex m_complex; public ComplexBuilder() { m_complex = new Complex(); } public Builder2 setFirst( String first ) { m_complex.m_first = first; return new Builder2(); } public class Builder2 { private Builder2() {} Builder3 setSecond( String second ) { m_complex.m_second = second; return new Builder3(); } } public class Builder3 { private Builder3() {} Builder4 setThird( String third ) { m_complex.m_third = third; return new Builder4(); } } public class Builder4 { private Builder4() {} Complex build() { return m_complex; } } } } As you can see, each setter of the builder class returns a different internal builder class. Each internal builder class provides exactly one setter method and the last one provides only a build() method. Now the construction of an object again looks like this: new ComplexBuilder() .setFirst( "first" ) .setSecond( "second" ) .setThird( "third" ) .build(); ...but there is no way to forget a needed parameter. The compiler wouldn't accept it. Optional parameters If I had optional parameters, I would use the last internal builder class Builder4 to set them like a "traditional" builder does, returning itself. Questions Is this a well known pattern? Does it have a special name? Do you see any pitfalls? Do you have any ideas to improve the implementation - in the sense of fewer lines of code?

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• Why is it still so hard to write software?

  - by nornagon

  Writing software, I find, is composed of two parts: the Idea, and the Implementation. The Idea is about thinking: "I have this problem; how do I solve it?" and further, "how do I solve it elegantly?" The answers to these questions are obtainable by thinking about algorithms and architecture. The ideas come partially through analysis and partially through insight and intuition. The Idea is usually the easy part. You talk to your friends and co-workers and you nut it out in a meeting or over coffee. It takes an hour or two, plus revisions as you implement and find new problems. The Implementation phase of software development is so difficult that we joke about it. "Oh," we say, "the rest is a Simple Matter of Code." Because it should be simple, but it never is. We used to write our code on punch cards, and that was hard: mistakes were very difficult to spot, so we had to spend extra effort making sure every line was perfect. Then we had serial terminals: we could see all our code at once, search through it, organise it hierarchically and create things abstracted from raw machine code. First we had assemblers, one level up from machine code. Mnemonics freed us from remembering the machine code. Then we had compilers, which freed us from remembering the instructions. We had virtual machines, which let us step away from machine-specific details. And now we have advanced tools like Eclipse and Xcode that perform analysis on our code to help us write code faster and avoid common pitfalls. But writing code is still hard. Writing code is about understanding large, complex systems, and tools we have today simply don't go very far to help us with that. When I click "find all references" in Eclipse, I get a list of them at the bottom of the window. I click on one, and I'm torn away from what I was looking at, forced to context switch. Java architecture is usually several levels deep, so I have to switch and switch and switch until I find what I'm really looking for -- by which time I've forgotten where I came from. And I do that all day until I've understood a system. It's taxing mentally, and Eclipse doesn't do much that couldn't be done in 1985 with grep, except eat hundreds of megs of RAM. Writing code has barely changed since we were staring at amber on black. We have the theoretical groundwork for much more advanced tools, tools that actually work to help us comprehend and extend the complex systems we work with every day. So why is writing code still so hard?

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• Sanity check on this idea for an Image Viewer in a web app

  - by Charlie Flowers

  I have an approach in mind for an image viewer in a web app, and want to get a sanity check and any thoughts you stackoverflowers might have. Here's the whirlwind nutshell summary: I'm working on an ASP.NET MVC application that will run in my company's retail stores. Even though it is a web application, we own the store machines and have control over them. We have a "windows agent" running on the store machine which we can talk to via http post (it is a WCF service, and our web app has permission to talk to it from the browser). One of the web pages needs to be an "image viewer" page with some common things like Rotate & Zoom. Now, there are some WebForms controls that offer Rotate and Zoom. However, they take up server resources and generate a good bit of traffic between the server and the browser. For example, the Rotate function would cause an ajax call to the server, which would then generate a new image written to a .NET Canvas object, which would then be written to a file on the server, which would then be returned from the ajax call and refreshed inside the browser. Normally, that's a pretty good way of doing things. But in our case, we have code running on the store machine that we can communicate with. This leads me to consider the following approach: When the user asks to view an image, we tell our "windows agent" to download it from our image server to the store machine. We then redirect our browser to our image viewer page, which will pull the image from the local file we just wrote to the store machine. When the user clicks "Rotate", we cause JavaScript code in the browser to call our "windows agent" software, asking it to perform the "Rotate" function. The "windows agent" does the rotation using the same kind of imaging control that would formerly have been used on the server, but it does so now on the store machine. Javascript in the browser then refreshes the image on the page to show the newly rotated image. Zoom and similar features would be implemented the same way. This seems to be much more efficient, scalable, and responsive for the end-users. However, I've never heard of anything like it being done, mostly because it's rare to have this combination of a web app plus a "windows agent" on the client machine. What do you think? Feasible? Reasonable? Any pitfalls I overlooked or improvements / suggestions you can see? Has anyone done anything like this who would like to offer the wisdom of experience? Thanks!

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• Question about Architecture for Viewing Images in ASP.NET MVC App

  - by Charlie Flowers

  I have an approach in mind for an image viewer in a web app, and want to get a sanity check and any thoughts you stackoverflowers might have. Here's the whirlwind nutshell summary: I'm working on an ASP.NET MVC application that will run in my company's retail stores. Even though it is a web application, we own the store machines and have control over them. We have a "windows agent" running on the store machine which we can talk to from the browser via javascript (it is a WCF service, and our web app has permission to talk to it from the browser). One of the web pages needs to be an "image viewer" page with some common things like Rotate & Zoom. Now, there are some WebForms controls that offer Rotate and Zoom. However, they take up server resources and generate a good bit of traffic between the server and the browser. For example, the Rotate function would cause an ajax call to the server, which would then generate a new image written to a .NET Canvas object, which would then be written to a file on the server, which would then be returned from the ajax call and refreshed inside the browser. Normally, that's a pretty good way of doing things. But in our case, we have code running on the store machine that we can communicate with. This leads me to consider the following approach: When the user asks to view an image, we tell our "windows agent" to download it from our image server to the store machine. We then redirect our browser to our image viewer page, which will pull the image from the local file we just wrote to the store machine. When the user clicks "Rotate", we cause JavaScript code in the browser to call our "windows agent" software, asking it to perform the "Rotate" function. The "windows agent" does the rotation using the same kind of imaging control that would formerly have been used on the server, but it does so now on the store machine. Javascript in the browser then refreshes the image on the page to show the newly rotated image. Zoom and similar features would be implemented the same way. This seems to be much more efficient, scalable, and responsive for the end-users. However, I've never heard of anything like it being done, mostly because it's rare to have this combination of a web app plus a "windows agent" on the client machine. What do you think? Feasible? Reasonable? Any pitfalls I overlooked or improvements / suggestions you can see? Has anyone done anything like this who would like to offer the wisdom of experience? Thanks!

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• How do you combine "Revision Control" with "WorkFlow" for R?

  - by Tal Galili

  Hello all, I remember coming across R users writing that they use "Revision control" (e.g: "Source control"), and I am curious to know: How do you combine "Revision control" with your statistical analysis WorkFlow? Two (very) interesting discussions talk about how to deal with the WorkFlow. But neither of them refer to the revision control element: http://stackoverflow.com/questions/1266279/how-to-organize-large-r-programs http://stackoverflow.com/questions/1429907/workflow-for-statistical-analysis-and-report-writing A Long Update To The Question: Following some of the people's answers, and Dirk's question in the comment, I would like to direct my question a bit more. After reading the Wiki article about "revision control" (which I was previously not familiar with), it was clear to me that when using revision control, what one does is to build a development structure of his code. This structure either leads to a "final product" or to several branches. When building something like, let's say, a website. There is usually one end product you work towards (the website), with some prototypes along the way. But when doing a statistical analysis, the work (to my view) is different. Sometimes you know where you want to get to. But more often, you explore. Explore cleaning the dataset. Explore different methods for statistical analysis, and ask various questions of your data (and I am writing this, knowing how Frank Harrell, and other experience statisticians feels about Data dredging). That is way the WorkFlow question with statistical programming is (in my view) a serious and deep question, raising many issues, The simpler ones are technical: Which revision control software do you use (and why) ? Which IDE do you use(and why) ? The more interesting question are about work process: How do you structure your files? What do you keep as a separate file and what as a revision? or asking in a different way - What should be a "branch" and what should be a "sub project" in your code? For example: When starting to explore your data, should a plot be creating and then erased because it didn't lead any where (but kept as a revision) or should there be a backup file of that path? How you solve this tension was my initial curiosity. The second question is "what might I be missing?". What rules (of thumb) should one follow so to avoid common pitfalls doing statistical programming with version control? In my intuition, I feel that statistical programming is inherently different then software development (I am writing this without being a real expert in statistical programming, and even less so in software development). That's way I am unsure which of the lessons I have read here about version control would be applicable. Thanks a lot, Tal

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• Circular database relationships. Good, Bad, Exceptions?

  - by jim

  I have been putting off developing this part of my app for sometime purely because I want to do this in a circular way but get the feeling its a bad idea from what I remember my lecturers telling me back in school. I have a design for an order system, ignoring the everything that doesn't pertain to this example I'm left with: CreditCard Customer Order I want it so that, Customers can have credit cards (0-n) Customers have orders (1-n) Orders have one customer(1-1) Orders have one credit card(1-1) Credit cards can have one customer(1-1) (unique ids so we can ignore uniqueness of cc number, husband/wife may share cc instances ect) Basically the last part is where the issue shows up, sometimes credit cards are declined and they wish to use a different one, this needs to update which their 'current' card is but this can only change the current card used for that order, not the other orders the customer may have on disk. Effectively this creates a circular design between the three tables. Possible solutions: Either Create the circular design, give references: cc ref to order, customer ref to cc customer ref to order or customer ref to cc customer ref to order create new table that references all three table ids and put unique on the order so that only one cc may be current to that order at any time Essentially both model the same design but translate differently, I am liking the latter option best at this point in time because it seems less circular and more central. (If that even makes sense) My questions are, What if any are the pros and cons of each? What is the pitfalls of circular relationships/dependancies? Is this a valid exception to the rule? Is there any reason I should pick the former over the latter? Thanks and let me know if there is anything you need clarified/explained. --Update/Edit-- I have noticed an error in the requirements I stated. Basically dropped the ball when trying to simplify things for SO. There is another table there for Payments which adds another layer. The catch, Orders can have multiple payments, with the possibility of using different credit cards. (if you really want to know even other forms of payment). Stating this here because I think the underlying issue is still the same and this only really adds another layer of complexity.

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• Persistent (purely functional) Red-Black trees on disk performance

  - by Waneck

  I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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• Can I use the [] operator in C++ to create virtual arrays

  - by Shane MacLaughlin

  I have a large code base, originally C ported to C++ many years ago, that is operating on a number of large arrays of spatial data. These arrays contain structs representing point and triangle entities that represent surface models. I need to refactor the code such that the specific way these entities are stored internally varies for specific scenarios. For example if the points lie on a regular flat grid, I don't need to store the X and Y coordinates, as they can be calculated on the fly, as can the triangles. Similarly, I want to take advantage of out of core tools such as STXXL for storage. The simplest way of doing this is replacing array access with put and get type functions, e.g. point[i].x = XV; becomes Point p = GetPoint(i); p.x = XV; PutPoint(i,p); As you can imagine, this is a very tedious refactor on a large code base, prone to all sorts of errors en route. What I'd like to do is write a class that mimics the array by overloading the [] operator. As the arrays already live on the heap, and move around with reallocs, the code already assumes that references into the array such as point *p = point + i; may not be used. Is this class feasible to write? For example writing the methods below in terms of the [] operator; void MyClass::PutPoint(int Index, Point p) { if (m_StorageStrategy == RegularGrid) { int xoffs,yoffs; ComputeGridFromIndex(Index,xoffs,yoffs); StoreGridPoint(xoffs,yoffs,p.z); } else m_PointArray[Index] = p; } } Point MyClass::GetPoint(int Index) { if (m_StorageStrategy == RegularGrid) { int xoffs,yoffs; ComputeGridFromIndex(Index,xoffs,yoffs); return GetGridPoint(xoffs,yoffs); // GetGridPoint returns Point } else return m_PointArray[Index]; } } My concern is that all the array classes I've seen tend to pass by reference, whereas I think I'll have to pass structs by value. I think it should work put other than performance, can anyone see any major pitfalls with this approach. n.b. the reason I have to pass by value is to get point[a].z = point[b].z + point[c].z to work correctly where the underlying storage type varies.

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• WinForm-style Invoke() in unmanaged C++

  - by Matt Green

  I've been playing with a DataBus-type design for a hobby project, and I ran into an issue. Back-end components need to notify the UI that something has happened. My implementation of the bus delivers the messages synchronously with respect to the sender. In other words, when you call Send(), the method blocks until all the handlers have called. (This allows callers to use stack memory management for event objects.) However, consider the case where an event handler updates the GUI in response to an event. If the handler is called, and the message sender lives on another thread, then the handler cannot update the GUI due to Win32's GUI elements having thread affinity. More dynamic platforms such as .NET allow you to handle this by calling a special Invoke() method to move the method call (and the arguments) to the UI thread. I'm guessing they use the .NET parking window or the like for these sorts of things. A morbid curiosity was born: can we do this in C++, even if we limit the scope of the problem? Can we make it nicer than existing solutions? I know Qt does something similar with the moveToThread() function. By nicer, I'll mention that I'm specifically trying to avoid code of the following form: if(! this->IsUIThread()) { Invoke(MainWindowPresenter::OnTracksAdded, e); return; } being at the top of every UI method. This dance was common in WinForms when dealing with this issue. I think this sort of concern should be isolated from the domain-specific code and a wrapper object made to deal with it. My implementation consists of: DeferredFunction - functor that stores the target method in a FastDelegate, and deep copies the single event argument. This is the object that is sent across thread boundaries. UIEventHandler - responsible for dispatching a single event from the bus. When the Execute() method is called, it checks the thread ID. If it does not match the UI thread ID (set at construction time), a DeferredFunction is allocated on the heap with the instance, method, and event argument. A pointer to it is sent to the UI thread via PostThreadMessage(). Finally, a hook function for the thread's message pump is used to call the DeferredFunction and de-allocate it. Alternatively, I can use a message loop filter, since my UI framework (WTL) supports them. Ultimately, is this a good idea? The whole message hooking thing makes me leery. The intent is certainly noble, but are there are any pitfalls I should know about? Or is there an easier way to do this?

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• Name hiding from inherited classes

  - by Mercerbearman

  I have the following sample code and I wanted to know the correct way to get access to the Pass method in the CBar class. Currently I have found 3 ways to get access to this method and they are as follows: Casting the object, ((CBar *) &foo)-Pass(1, 2, 3); Using this syntax, foo.CBar::Pass(1,2,3); Use the "using" syntax in the CFoo class declaration, using CBar::Pass. The following is an example of a simple project to test this capability. Foo.h #include "bar.h" class CFoo : public CBar { private: double m_a; double m_b; public: CFoo(void); ~CFoo(void); void Pass(double a, double b); }; Foo.cpp #include "Foo.h" CFoo::CFoo(void) { m_a = 0.0; m_b = 0.0; } CFoo::~CFoo(void) { } void CFoo::Pass(double a, double b) { m_a = a; m_b = b; } Bar.h class CBar { int m_x; int m_y; int m_z; public: CBar(void); ~CBar(void); void Pass(int x, int y, int z); }; Bar.cpp #include "Bar.h" CBar::CBar(void) { m_x = 0; m_y = 0; m_z = 0; } CBar::~CBar(void) { } void CBar::Pass(int x, int y, int z) { m_x = x; m_y = y; m_z = z; } And my main class DoStuff.cpp #include "DoStuff.h" #include "Foo.h" CDoStuff::CDoStuff(void) { } CDoStuff::~CDoStuff(void) { } int main() { CFoo foo, foo1, foo2; //This only gets to the Pass method in Foo. foo.Pass(2.5, 3.5); //Gets access to Pass method in Bar. foo1.CBar::Pass(5,10,15); //Can also case and access by location for the same result?? ((CBar *) &foo2)->Pass(100,200,300); return 0; } Are each of these options viable? Are some preferred? Are there pitfalls with using any one of the methods listed? I am especially curious about the foo.CBar::Pass(1,2,3) syntax. Thanks, B

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• Consistent PHP _SERVER variables between Apache and nginx?

  - by Alix Axel

  I'm not sure if this should be asked here or on ServerFault, but here it goes... I am trying to get started on nginx with PHP-FPM, but I noticed that the server block setup I currently have (gathered from several guides including the nginx Pitfalls wiki page) produces $_SERVER variables that are different from what I'm used to seeing in Apache setups. After spending the last evening trying to "fix" this, I decided to install Apache on my local computer and gather the variables that I'm interested in under different conditions so that I could try and mimic them on nginx. The Apache setup I've on my computer has only one mod_rewrite rule: RewriteEngine On RewriteCond %{SCRIPT_FILENAME} !-f RewriteCond %{SCRIPT_FILENAME} !-d RewriteRule ^(.*)$ /index.php/$1 [L] And these are the values I get for different request URIs (left is Apache, right is nginx): localhost/ - http://www.mergely.com/GnzBHRV1/ localhost/foo/bar/baz/?foo=bar - http://www.mergely.com/VwsT8oTf/ localhost/index.php/foo/bar/baz/?foo=bar - http://www.mergely.com/VGEFehfT/ What configuration directives would allow me to get similar values on requests handled by nginx? My current configuration in nginx is: server { listen 80; listen 443 ssl; server_name default; ssl_certificate /etc/nginx/certificates/dummy.crt; ssl_certificate_key /etc/nginx/certificates/dummy.key; root /var/www/default/html; index index.php index.html; autoindex on; location / { try_files $uri $uri/ /index.php; } location ~ /(?:favicon[.]ico|robots[.]txt)$ { log_not_found off; } location ~* [.]php { #try_files $uri =404; include fastcgi_params; fastcgi_pass unix:/var/run/php5-fpm.sock; fastcgi_index index.php; fastcgi_split_path_info ^(.+[.]php)(/.+)$; } location ~* [.]ht { deny all; } } And my fastcgi_params file looks like this: fastcgi_param PATH_INFO $fastcgi_path_info; fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info; fastcgi_param QUERY_STRING $query_string; fastcgi_param REQUEST_METHOD $request_method; fastcgi_param CONTENT_TYPE $content_type; fastcgi_param CONTENT_LENGTH $content_length; fastcgi_param SCRIPT_NAME $fastcgi_script_name; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; fastcgi_param REQUEST_URI $request_uri; fastcgi_param DOCUMENT_URI $document_uri; fastcgi_param DOCUMENT_ROOT $document_root; fastcgi_param SERVER_PROTOCOL $server_protocol; fastcgi_param GATEWAY_INTERFACE CGI/1.1; fastcgi_param SERVER_SOFTWARE nginx/$nginx_version; fastcgi_param REMOTE_ADDR $remote_addr; fastcgi_param REMOTE_PORT $remote_port; fastcgi_param SERVER_ADDR $server_addr; fastcgi_param SERVER_PORT $server_port; fastcgi_param SERVER_NAME $server_name; fastcgi_param HTTPS $https; I know that the try_files $uri =404; directive is commented and that it is a security vulnerability but, if I uncomment it, the third request (localhost/index.php/foo/bar/baz/?foo=bar) will return a 404. It's also worth noting that my PHP cgi.fix_pathinfo in On (contrary to what some of the guides recommend), if I try to set it to Off, I'm presented with a "Access denied." message on every PHP request. I'm running PHP 5.4.8 and nginx/1.1.19. I don't know what else to try... Help?

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• How to redirect http requests to https (nginx)

  - by spuder

  There appear to be many questions and guides out there that instruct how to setup nginx to redirect http requests to https. Many are outdated, or just flat out wrong. # MANAGED BY PUPPET upstream gitlab { server unix:/home/git/gitlab/tmp/sockets/gitlab.socket; } # setup server with or without https depending on gitlab::gitlab_ssl variable server { listen *:80; server_name gitlab.localdomain; server_tokens off; root /nowhere; rewrite ^ https://$server_name$request_uri permanent; } server { listen *:443 ssl default_server; server_name gitlab.localdomain; server_tokens off; root /home/git/gitlab/public; ssl on; ssl_certificate /etc/ssl/certs/ssl-cert-snakeoil.pem; ssl_certificate_key /etc/ssl/private/ssl-cert-snakeoil.key; ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2; ssl_ciphers AES:HIGH:!ADH:!MDF; ssl_prefer_server_ciphers on; # individual nginx logs for this gitlab vhost access_log /var/log/nginx/gitlab_access.log; error_log /var/log/nginx/gitlab_error.log; location / { # serve static files from defined root folder;. # @gitlab is a named location for the upstream fallback, see below try_files $uri $uri/index.html $uri.html @gitlab; } # if a file, which is not found in the root folder is requested, # then the proxy pass the request to the upsteam (gitlab puma) location @gitlab { proxy_read_timeout 300; # https://github.com/gitlabhq/gitlabhq/issues/694 proxy_connect_timeout 300; # https://github.com/gitlabhq/gitlabhq/issues/694 proxy_redirect off; proxy_set_header X-Forwarded-Proto $scheme; proxy_set_header X-Forwarded-Ssl on; proxy_set_header Host $http_host; proxy_set_header X-Real-IP $remote_addr; proxy_pass http://gitlab; } } I've restarted after every configuration change, and yet I still only get the 'Welcome to nginx' page when visiting http://192.168.33.10. whereas https://192.168.33.10 works perfectly. Why will nginx still not redirect http requests to https? I've also tried the following configurations listen *:80; server_name <%= @fqdn %>; #root /nowhere; #rewrite ^ https://$server_name$request_uri? permanent; #rewrite ^ https://$server_name$request_uri permanent; #return 301 https://$server_name$request_uri; #return 301 http://$server_name$request_uri; #return 301 http://192.168.33.10$request_uri; return 301 http://$host$request_uri; The logs tailf /var/log/nginx/access.log 192.168.33.1 - - [22/Oct/2013:03:41:39 +0000] "GET / HTTP/1.1" 304 0 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Firefox/24.0" 192.168.33.1 - - [22/Oct/2013:03:44:43 +0000] "GET / HTTP/1.1" 200 133 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Firefox/24.0" tailf /var/log/nginx/gitlab_error.lob 2013/10/22 02:29:14 [crit] 27226#0: *1 connect() to unix:/home/git/gitlab/tmp/sockets/gitlab.socket failed (2: No such file or directory) while connecting to upstream, client: 192.168.33.1, server: gitlab.localdomain, request: "GET / HTTP/1.1", upstream: "http://unix:/home/git/gitlab/tmp/sockets/gitlab.socket:/", host: "192.168.33.10" Resources http://wiki.nginx.org/Pitfalls How to make nginx redirect How to force or redirect to SSL in nginx? nginx ssl redirect Nginx & Https Redirection https://www.tinywp.in/301-redirect-wordpress/ How to force or redirect to SSL in nginx?

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• Set up lnux box for hosting a-z

  - by microchasm

  I am in the process of reinstalling the OS on a machine that will be used to host a couple of apps for our business. The apps will be local only; access from external clients will be via vpn only. The prior setup used a hosting control panel (Plesk) for most of the admin, and I was looking at using another similar piece of software for the reinstall - but I figured I should finally learn how it all works. I can do most of the things the software would do for me, but am unclear on the symbiosis of it all. This is all an attempt to further distance myself from the land of Configuration Programmer/Programmer, if at all possible. I can't find a full walkthrough anywhere for what I'm looking for, so I thought I'd put up this question, and if people can help me on the way I will edit this with the answers, and document my progress/pitfalls. Hopefully someday this will help someone down the line. The details: CentOS 5.5 x86_64 httpd: Apache/2.2.3 mysql: 5.0.77 (to be upgraded) php: 5.1 (to be upgraded) The requirements: SECURITY!! Secure file transfer Secure client access (SSL Certs and CA) Secure data storage Virtualhosts/multiple subdomains Local email would be nice, but not critical The Steps: Download latest CentOS DVD-iso (torrent worked great for me). Install CentOS: While going through the install, I checked the Server Components option thinking I was going to be using another Plesk-like admin. In hindsight, considering I've decided to try to go my own way, this probably wasn't the best idea. Basic config: Setup users, networking/ip address etc. Yum update/upgrade. Upgrade PHP: To upgrade PHP to the latest version, I had to look to another repo outside CentOS. IUS looks great and I'm happy I found it! cd /tmp #wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-1-1.ius.el5.noarch.rpm #rpm -Uvh epel-release-1-1.ius.el5.noarch.rpm #wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1-4.ius.el5.noarch.rpm #rpm -Uvh ius-release-1-4.ius.el5.noarch.rpm yum list | grep -w \.ius\. [will list all packages available in the IUS repo] rpm -qa | grep php [will list installed packages needed to be removed. the installed packages need to be removed before you can install the IUS packages otherwise there will be conflicts] #yum shell >remove php-gd php-cli php-odbc php-mbstring php-pdo php php-xml php-common php-ldap php-mysql php-imap Setting up Remove Process >install php53 php53-mcrypt php53-mysql php53-cli php53-common php53-ldap php53-imap php53-devel >transaction solve >transaction run Leaving Shell #php -v PHP 5.3.2 (cli) (built: Apr 6 2010 18:13:45) This process removes the old version of PHP and installs the latest. To upgrade mysql: Pretty much the same process as above with PHP #/etc/init.d/mysqld stop [OK] rpm -qa | grep mysql [installed mysql packages] #yum shell >remove mysql mysql-server Setting up Remove Process >install mysql51 mysql51-server mysql51-devel >transaction solve >transaction run Leaving Shell #service mysqld start [OK] #mysql -v Server version: 5.1.42-ius Distributed by The IUS Community Project The above upgrade instructions courtesy of IUS wiki: http://wiki.iuscommunity.org/Doc/ClientUsageGuide Create a chroot jail to hold sftp user via rssh. This will force SCP/SFTP and will circumvent traditional FTP server setup. #cd /tmp #wget http://dag.wieers.com/rpm/packages/rssh/rssh-2.3.2-1.2.el5.rf.x86_64.rpm #rpm -ivh rssh-2.3.2-1.2.el5.rf.x86_64.rpm #useradd -m -d /home/dev -s /usr/bin/rssh dev #passwd dev Edit /etc/rssh.conf to grant access to SFTP to rssh users. #vi /etc/rssh.conf Uncomment line allowscp This allows me to connect to the machine via SFTP protocol in Transmit (my FTP program of choice; I'm sure it's similar with other FTP apps). Above instructions for SFTP appropriated (with appreciation!) from http://www.cyberciti.biz/tips/linux-unix-restrict-shell-access-with-rssh.html And this is where I'm at. I will keep editing this as I make progress. Any tips on how to Configure virtual interfaces/ip based virtual hosts for SSL, setting up a CA, or anything else would be appreciated.

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• Set up lnux box for hosting a-z [apache mysql php ssl]

  - by microchasm

  I am in the process of reinstalling the OS on a machine that will be used to host a couple of apps for our business. The apps will be local only; access from external clients will be via vpn only. The prior setup used a hosting control panel (Plesk) for most of the admin, and I was looking at using another similar piece of software for the reinstall - but I figured I should finally learn how it all works. I can do most of the things the software would do for me, but am unclear on the symbiosis of it all. This is all an attempt to further distance myself from the land of Configuration Programmer/Programmer, if at all possible. I can't find a full walkthrough anywhere for what I'm looking for, so I thought I'd put up this question, and if people can help me on the way I will edit this with the answers, and document my progress/pitfalls. Hopefully someday this will help someone down the line. The details: CentOS 5.5 x86_64 httpd: Apache/2.2.3 mysql: 5.0.77 (to be upgraded) php: 5.1 (to be upgraded) The requirements: SECURITY!! Secure file transfer Secure client access (SSL Certs and CA) Secure data storage Virtualhosts/multiple subdomains Local email would be nice, but not critical The Steps: Download latest CentOS DVD-iso (torrent worked great for me). Install CentOS: While going through the install, I checked the Server Components option thinking I was going to be using another Plesk-like admin. In hindsight, considering I've decided to try to go my own way, this probably wasn't the best idea. Basic config: Setup users, networking/ip address etc. Yum update/upgrade. Upgrade PHP: To upgrade PHP to the latest version, I had to look to another repo outside CentOS. IUS looks great and I'm happy I found it! cd /tmp #wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-1-1.ius.el5.noarch.rpm #rpm -Uvh epel-release-1-1.ius.el5.noarch.rpm #wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1-4.ius.el5.noarch.rpm #rpm -Uvh ius-release-1-4.ius.el5.noarch.rpm yum list | grep -w \.ius\. [will list all packages available in the IUS repo] rpm -qa | grep php [will list installed packages needed to be removed. the installed packages need to be removed before you can install the IUS packages otherwise there will be conflicts] #yum shell >remove php-gd php-cli php-odbc php-mbstring php-pdo php php-xml php-common php-ldap php-mysql php-imap Setting up Remove Process >install php53 php53-mcrypt php53-mysql php53-cli php53-common php53-ldap php53-imap php53-devel >transaction solve >transaction run Leaving Shell #php -v PHP 5.3.2 (cli) (built: Apr 6 2010 18:13:45) This process removes the old version of PHP and installs the latest. To upgrade mysql: Pretty much the same process as above with PHP #/etc/init.d/mysqld stop [OK] rpm -qa | grep mysql [installed mysql packages] #yum shell >remove mysql mysql-server Setting up Remove Process >install mysql51 mysql51-server mysql51-devel >transaction solve >transaction run Leaving Shell #service mysqld start [OK] #mysql -v Server version: 5.1.42-ius Distributed by The IUS Community Project And this is where I'm at. I will keep editing this as I make progress. Any tips on how to Configure Virtualhosts for SSL, setting up a CA, setting up SFTP with openSSH, or anything else would be appreciated.

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• Automating Form Login

  - by Greg_Gutkin

  Introduction A common task in configuring a web application for proxying in Pagelet Producer is setting up form autologin. PP provides a wizard-like tool for detecting the login form fields, but this is usually only the first step in configuring this feature. If the generated configuration doesn't seem to work, some additional manual modifications will be needed to complete the setup. This article will try to guide you through this process while steering you away from common pitfalls. For the purposes of this article, let's assume the following characteristics about your environment: Web Application Base URL: http://host/app (configured as Resource Source URL in PP) Pagelet Producer Base URL: http://pp/pagelets Form Field Auto-Detection Form Autologin is configured in the PP Admin UI under resource_name/Autologin/Form Login. First, you'll enter the URL to the login form under "Login Form Identification". This will enable the admin wizard to connect to and display the login page. Caution: RedirectsMake sure the entered URL matches what you see in the browser's address bar, when the application login page is displayed. For example, even though you may be able to reach the login page by simply typing http://host/app, the URL you end up on may change to http://host/app/login via browser redirect(s).The second URL is the one you will want to use. Caution: External Login ServersThe login page may actually come from a different server than the application you are trying to proxy. For example, you may notice that the login page URL changes to http://hostB/appB. This is common when external SSO products are involved. There are two ways of dealing with this situation. One is to configure Pagelet Producer to participate in SSO. This approach is out of scope of this article and is discussed in a separate whitepaper (TODO add link). The second approach is to use the autologin feature to provide stored credentials to the SSO login form. Since the login form URL is not an extension of the application base URL (PP resource URL), you will need to add a new PP resource for the SSO server and configure the login form on that resource instead of the original application resource. One side benefit of this additional resource is that it can reused for other applications relying on the same SSO server for login. After entering the login page URL (make sure dropdown says "URL"), click "Automatically Detect Form Fields". This will bring up the web app's login page in a new browser window. Fill it out and submit it as you would normally. If everything goes right, Pagelet Producer will intercept the submitted values and fill out all the needed configuration data in the Admin UI. If the login form window doesn't close or configuration data doesn't get filled in, you may have not entered the login page URL correctly. Review the two cautionary notes above and make any necessary changes. If the form fields got filled automatically, it's time to save the configuration and test it out. If you can access a protected area of the backend application via a proxied PP URL without filling out its login form, then you are pretty much done with login form configuration. The only other step you will need to complete before declaring this aspect of configuration production ready is configuring form field source. You may skip to that section below. Manual Login Form Identification Let's take a closer look at Login Form Identification. This determines how Pagelet Producer recognizes login forms as such. URL The most efficient way of detecting login forms is by looking at the page URL. This method can only be used under the following conditions: Login page URL must be different from the post login application URLs. Login page URL must stay constant regardless of the path it takes to reach the page. For example, reaching the login page by going to the application base URL or to a specific protected URL must result in a redirect to the same login page URL (query string excluded). If only the query string parameters change, just leave out the query string from the configured login page URL. If either of these conditions is not fullfilled, you must switch to the RegEx approach below. RegEx If the login page URL is not uniform enough across all scenarios or is indistinguishable from other page locations, PP can be configured to recognize it by looking at the page markup itself. This is accomplished by changing the dropdown to "RegEx". If regular expressions scare you, take comfort from the fact that in most cases you won't need to enter any special regex characters. Let's look at an example: Say you have a login form that looks like <form id='loginForm' action='login?from=pageA' > <input id='user'> <input id='pass'> </form> Since this form has an id attribute, you can be reasonably sure that this login form can be uniquely identified across the web application by this snippet: "id='loginForm'". (Unless, of course your backend web application contains login forms to other apps). Since no wildcards are needed to find this snippet, you can just enter it as is into the RegEx field - no special regular expression characters needed! If the web developer who created the form wasn't kind enough to provide a unique id, you will need to look for other snippets of the page to uniquely identify it. It could be the action URL, an input field id, or some other markup fragment. You should abstain from using UI text as an identifier it may change in translated versions of the page and prevent the login page logic from working for international users. You may need to turn to regular expression wildcard syntax if no simple matches work. For more information on regular expression, refer to the Resources section. Form Submit Location Now we'll look at the form submit location. If the captured URL contains query string parameters that will likely change from one form submission to the next, you will need to change its type to RegEx. This type will tell Pagelet Producer to parse the login page for the action URL and submit to the value found. The regular expression needs to point at the actual action URL with its first grouping expression. Taking the example form definition above, the form submit location regex would be: action='(.*?)' The parentheses are used to identify the actual action URL, while the rest of the expression provides the context for finding it. Expression .*? is a so-called reluctant wildcard that matches any character excluding the single quote that follows. See Resources section below for further information on regular expressions. Manual Form Field Detection If the Admin UI form field detection wizard fails to populate login form configuration page, you will have to enter the fields by hand. Use a built-in browser developer tool or addon (e.g. Firebug) to inspect the form element and its children input elements. For each input element (including hidden elements), create an entry under Form Fields. Change its Source according to the next section. Form Field Source Change the source of any of the fields not exposed to the users of the login form (i.e. hidden fields) to "Generated". This means Pagelet Producer will just use the values returned by the web app rather than supplying values it stored. For fields that contain sensitive data or vary from user to user (e.g. username & password), change the source to User (Credential) Vault. Logging Support To help you troubleshoot you autologin configuration, PP provides some useful logging support. To turn on detailed logging for the autologin feature, navigate to Settings in Admin UI. Under Logging, change the log level for AutoLogin to Finest. Known Limitations Autologin feature may not work as expected if login form fields (not just the values, but the DOM elements themselves) are generated dynamically by client side JavaScript. Resources RegEx RegEx Reference from Java RegEx Test Tool

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• September Independent Oracle User Group (IOUG) Regional Events:

  - by Mandy Ho

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} September 5, 2012 – Denver, CO Oracle 11g Database Upgrade Seminar Join Roy Swonger, Senior Director of software development at Oracle to learn about upgrading to Oracle Database 11g. Topics include: All the required preparatory steps Database upgrade strategies Post-upgrade performance analysis Helpful tips and common pitfalls to watch out for http://www.oracle.com/webapps/events/ns/EventsDetail.jsp?p_eventId=152242&src=7598177&src=7598177&Act=4 September 6, 2012 – Salt Lake City, UT Fall Symposium 2012 Plan to join us for our annual fall event on Sept 6. They day will be filled with learning and networking with tracks focused on Applications, APEX, BI, Development and DBA Topics. This event is free for UTOUG members to attend, but please register. http://www.utoug.org/apex/f?p=972:2:6686308836668467::::P2_EVENT_ID:121 September 6, 2012 – Portland, OR Oracle’s Hands on Workshop Series focused on providing Defense-in-Depth Solutions to secure data at the source, reduce risk and simplify compliance The Oracle Database Security Workshop is a one-day hands-on session for IT Managers, IT Security Architects and Oracle DBAs who are looking for solutions to address their information protection, privacy, and accountability challenges within their Oracle database environment. Most security programs offered today fail toadequately address database security. Customers continue to be challenged tosecure information against loss and protect the integrity of sensitiveinformation like critical financial data, personally identifiable information(PII) and credit card data for PCI compliance. http://nwoug.org/content.aspx?page_id=87&club_id=165905&item_id=241082 September 11, 2012 – Montreal, QC APEXposed! For APEX aficionados – join ODTUG in Montreal, September 11-12 for APEXposed! Topics will include Dynamic Actions, Plug-ins, Tuning, and Building Mobile Apps. The cost is $399 US and early registration ends August 15th. For more information: http://www.odtugapextraining.com  September 11, 2012 – Philadelphia, PA Big Data & What are we still doing wrong with Tom Kyte Tom Kyte is a Senior Technical Architect in Oracle's Server Technology Division. Tom is the Tom behind the AskTom column in Oracle Magazine and is also the author of Expert Oracle Database Architecture (Apress, 2005/2009) among other books Abstract: Big Data The term "big data" draws a lot of attention, but behind the hype there's a simple story. For decades, companies have been making business decisions based on transactional data stored in relational databases. However, beyond that critical data is a potential treasure trove of less structured data: weblogs, social media, email, sensors, and photographs that can be mined for useful information. This presentation will take a look at what Big Data is and means - and Oracle's strategy for handling it Abstract: What are we still doing wrong? I've given many best practices presentations in the last 10 years. I've given many worst practices presentations in the last 10 years. I've seen some things change over the last ten years and many other things stay exactly the same. In this talk - we'll be taking a look at the good and the bad - what we do right and what we continue to do wrong over and over again. We'll look at why "Why" is probably the right initial answer to most any question. We'll look at how we get to "Know what we Know", and why that can be both a help and a hindrance. We'll peek at "Best Practices" and tie them into what I term "Worst Practices". In short, a talk on the good and the bad. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} http://ioug.itconvergence.com/pls/apex/f?p=207:27:3669516430980563::NO September 12, 2012- New York, NY NYOUG Fall General Meeting “Trends in Database Administration and Why the Future of Database Administration is the Vdba” http://www.nyoug.org/upcoming_events.htm#General_Meeting1 September 21, 2012 – Cleveland, OH Oracle Database 11g for Developers: What You need to know or Oracle Database 11g New Features for Developers Attendees are introduced to the new and improved features of Oracle 11g (both Oracle 11g R1 and Oracle 11g R2) that directly impact application development. Special emphasis is placed on features that reduce development time, make development simpler, improve performance, or speed deployment. Specific topics include: New SQL functions, virtual columns, result caching, XML improvements, pivot statements, JDBC improvements, and PL/SQL enhancements such as compound triggers. http://www.neooug.org/ September 24, 2012 – Ottawa, ON Introduction to Oracle Spatial The free Oracle Locator functionality, and the Oracle Spatial option which dramatically extends Locator, are very useful, but poorly understood capabilities of the database. In the afternoon we will extend into additional areas selected from: storage and performance; answering business problems with spatial queries; using Oracle Maps in OBIEE; an overview and capabilities of Oracle Topology; under the covers with GeoCoding. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} http://www.oug-ottawa.org/pls/htmldb/f?p=327:27:4209274028390246::NO

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• Integration Patterns with Azure Service Bus Relay, Part 1: Exposing the on-premise service

  - by Elton Stoneman

  We're in the process of delivering an enabling project to expose on-premise WCF services securely to Internet consumers. The Azure Service Bus Relay is doing the clever stuff, we register our on-premise service with Azure, consumers call into our .servicebus.windows.net namespace, and their requests are relayed and serviced on-premise. In theory it's all wonderfully simple; by using the relay we get lots of protocol options, free HTTPS and load balancing, and by integrating to ACS we get plenty of security options. Part of our delivery is a suite of sample consumers for the service - .NET, jQuery, PHP - and this set of posts will cover setting up the service and the consumers. Part 1: Exposing the on-premise service In theory, this is ultra-straightforward. In practice, and on a dev laptop it is - but in a corporate network with firewalls and proxies, it isn't, so we'll walkthrough some of the pitfalls. Note that I'm using the "old" Azure portal which will soon be out of date, but the new shiny portal should have the same steps available and be easier to use. We start with a simple WCF service which takes a string as input, reverses the string and returns it. The Part 1 version of the code is on GitHub here: on GitHub here: IPASBR Part 1. Configuring Azure Service Bus Start by logging into the Azure portal and registering a Service Bus namespace which will be our endpoint in the cloud. Give it a globally unique name, set it up somewhere near you (if you’re in Europe, remember Europe (North) is Ireland, and Europe (West) is the Netherlands), and  enable ACS integration by ticking "Access Control" as a service: Authenticating and authorizing to ACS When we try to register our on-premise service as a listener for the Service Bus endpoint, we need to supply credentials, which means only trusted service providers can act as listeners. We can use the default "owner" credentials, but that has admin permissions so a dedicated service account is better (Neil Mackenzie has a good post On Not Using owner with the Azure AppFabric Service Bus with lots of permission details). Click on "Access Control Service" for the namespace, navigate to Service Identities and add a new one. Give the new account a sensible name and description: Let ACS generate a symmetric key for you (this will be the shared secret we use in the on-premise service to authenticate as a listener), but be sure to set the expiration date to something usable. The portal defaults to expiring new identities after 1 year - but when your year is up *your identity will expire without warning* and everything will stop working. In production, you'll need governance to manage identity expiration and a process to make sure you renew identities and roll new keys regularly. The new service identity needs to be authorized to listen on the service bus endpoint. This is done through claim mapping in ACS - we'll set up a rule that says if the nameidentifier in the input claims has the value serviceProvider, in the output we'll have an action claim with the value Listen. In the ACS portal you'll see that there is already a Relying Party Application set up for ServiceBus, which has a Default rule group. Edit the rule group and click Add to add this new rule: The values to use are: Issuer: Access Control Service Input claim type: http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier Input claim value: serviceProvider Output claim type: net.windows.servicebus.action Output claim value: Listen When your service namespace and identity are set up, open the Part 1 solution and put your own namespace, service identity name and secret key into the file AzureConnectionDetails.xml in Solution Items, e.g: <azure namespace="sixeyed-ipasbr">    <!-- ACS credentials for the listening service (Part1):-->   <service identityName="serviceProvider"            symmetricKey="nuR2tHhlrTCqf4YwjT2RA2BZ/+xa23euaRJNLh1a/V4="/>  </azure> Build the solution, and the T4 template will generate the Web.config for the service project with your Azure details in the transportClientEndpointBehavior:           <behavior name="SharedSecret">             <transportClientEndpointBehavior credentialType="SharedSecret">               <clientCredentials>                 <sharedSecret issuerName="serviceProvider"                               issuerSecret="nuR2tHhlrTCqf4YwjT2RA2BZ/+xa23euaRJNLh1a/V4="/>               </clientCredentials>             </transportClientEndpointBehavior>           </behavior> , and your service namespace in the Azure endpoint:         <!-- Azure Service Bus endpoints -->          <endpoint address="sb://sixeyed-ipasbr.servicebus.windows.net/net"                   binding="netTcpRelayBinding"                   contract="Sixeyed.Ipasbr.Services.IFormatService"                   behaviorConfiguration="SharedSecret">         </endpoint> The sample project is hosted in IIS, but it won't register with Azure until the service is activated. Typically you'd install AppFabric 1.1 for Widnows Server and set the service to auto-start in IIS, but for dev just navigate to the local REST URL, which will activate the service and register it with Azure. Testing the service locally As well as an Azure endpoint, the service has a WebHttpBinding for local REST access:         <!-- local REST endpoint for internal use -->         <endpoint address="rest"                   binding="webHttpBinding"                   behaviorConfiguration="RESTBehavior"                   contract="Sixeyed.Ipasbr.Services.IFormatService" /> Build the service, then navigate to: http://localhost/Sixeyed.Ipasbr.Services/FormatService.svc/rest/reverse?string=abc123 - and you should see the reversed string response: If your network allows it, you'll get the expected response as before, but in the background your service will also be listening in the cloud. Good stuff! Who needs network security? Onto the next post for consuming the service with the netTcpRelayBinding.  Setting up network access to Azure But, if you get an error, it's because your network is secured and it's doing something to stop the relay working. The Service Bus relay bindings try to use direct TCP connections to Azure, so if ports 9350-9354 are available *outbound*, then the relay will run through them. If not, the binding steps down to standard HTTP, and issues a CONNECT across port 443 or 80 to set up a tunnel for the relay. If your network security guys are doing their job, the first option will be blocked by the firewall, and the second option will be blocked by the proxy, so you'll get this error: System.ServiceModel.CommunicationException: Unable to reach sixeyed-ipasbr.servicebus.windows.net via TCP (9351, 9352) or HTTP (80, 443) - and that will probably be the start of lots of discussions. Network guys don't really like giving servers special permissions for the web proxy, and they really don't like opening ports, so they'll need to be convinced about this. The resolution in our case was to put up a dedicated box in a DMZ, tinker with the firewall and the proxy until we got a relay connection working, then run some traffic which the the network guys monitored to do a security assessment afterwards. Along the way we hit a few more issues, diagnosed mainly with Fiddler and Wireshark: System.Net.ProtocolViolationException: Chunked encoding upload is not supported on the HTTP/1.0 protocol - this means the TCP ports are not available, so Azure tries to relay messaging traffic across HTTP. The service can access the endpoint, but the proxy is downgrading traffic to HTTP 1.0, which does not support tunneling, so Azure can’t make its connection. We were using the Squid proxy, version 2.6. The Squid project is incrementally adding HTTP 1.1 support, but there's no definitive list of what's supported in what version (here are some hints). System.ServiceModel.Security.SecurityNegotiationException: The X.509 certificate CN=servicebus.windows.net chain building failed. The certificate that was used has a trust chain that cannot be verified. Replace the certificate or change the certificateValidationMode. The evocation function was unable to check revocation because the revocation server was offline. - by this point we'd given up on the HTTP proxy and opened the TCP ports. We got this error when the relay binding does it's authentication hop to ACS. The messaging traffic is TCP, but the control traffic still goes over HTTP, and as part of the ACS authentication the process checks with a revocation server to see if Microsoft’s ACS cert is still valid, so the proxy still needs some clearance. The service account (the IIS app pool identity) needs access to: www.public-trust.com mscrl.microsoft.com We still got this error periodically with different accounts running the app pool. We fixed that by ensuring the machine-wide proxy settings are set up, so every account uses the correct proxy: netsh winhttp set proxy proxy-server="http://proxy.x.y.z" - and you might need to run this to clear out your credential cache: certutil -urlcache * delete If your network guys end up grudgingly opening ports, they can restrict connections to the IP address range for your chosen Azure datacentre, which might make them happier - see Windows Azure Datacenter IP Ranges. After all that you've hopefully got an on-premise service listening in the cloud, which you can consume from pretty much any technology.

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• April Oracle Database Events

  - by Mandy Ho

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} April 17-18, 2012 – Moscow, Russia Oracle Develop Conference The Oracle database developer conference, Oracle Develop, will visit Moscow, Russia and Hyderabad, India this spring. Oracle Develop includes a database development track, which contains .NET sessions and hands-on lab led by an Oracle .NET product manager. Register today before the event fills up. http://www.oracle.com/javaone/ru-en/index.html Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} April 24, 26 – San Diego, CA & San Jose, CA ISC2 Leadership Regional Event Series Oracle at (ISC)2 Security Leadership Series: Herding Clouds -- Managing Cloud Security Concerns and Expectations Join us for his interactive day-long session where industry leaders, including Oracle solution experts, will talk about how to: dispel the top Cloud security myths minimize "rogue Cloud" implementations identify potential compliance pitfalls and how to avoid them develop contract language for your cloud providers manage users across your fractured datacenter leverage existing technologies to protect data as it moves from the enterprise to the cloud http://www.oracle.com/webapps/events/ns/EventsDetail.jsp?p_eventId=146972&src=7239493&src=7239493&Act=228 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} April 22-26, 2012 – Las Vegas, NV IOUG Collaborate 12 From April 22-26, 2012, Oracle takes Las Vegas. Thousands of Oracle professionals will descend upon the Mandalay Bay Convention Center for a weeks worth of education sessions, networking opportunities and more, at the only user-driven and user-run Oracle conference - COLLABORATE 12.  Your COLLABORATE 12 - IOUG Forum registration comes complete with a bonus- a full day Deep Dive education program on Sunday! Choose from numerous hot topics, including Real World Performance, High Availability and more, presented by legendary and seasoned Oracle pros, including Tom Kyte and Craig Shallahamer. http://www.oracle.com/webapps/events/ns/EventsDetail.jsp?p_eventId=143637&src=7360364&src=7360364&Act=5 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} Independent Oracle User Group (IOUG) Regional Events: April 16, 2012 – Columbus, Ohio Ohio Oracle Users Group Higher Performance PL/PQL and Oracle Database 11g PL/SQL New Features – Featuring Steven Feuerstein http://www.ooug.org/ Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} April 26, 2012- Irving, TX Dallas Oracle Users Group Oracle Database Forum: 5-7PM Oracle Corporation, 6031 Connection Drive Irving, TX http://memberservices.membee.com/538/irmevents.aspx?id=64 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} Apr 30, 2012- Los Angeles, CA Real World Performance Tour A full day of real world database performance with: Tom Kyte, author of the ever popular AskTom Blog, Andrew Holdsworth, head of Oracle's Real World Performance Team, and Graham Wood, renowned Oracle Database performance architect. Through discussion, debate and demos, they’ll show you how to master performance engineering topics like: Best practices for designing hardware architectures and how to spot and fix bad design. How to develop applications that deliver the fastest possible performance without sacrificing accuracy.  New for 2012! Updates on Enterprise Manager, Exadata, and what these technologies mean to your current systems. http://www.ioug.org/Events/ADayofRealWorldPerformance/tabid/194/Default.aspx

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• C# Performance Pitfall – Interop Scenarios Change the Rules

  - by Reed

  C# and .NET, overall, really do have fantastic performance in my opinion.  That being said, the performance characteristics dramatically differ from native programming, and take some relearning if you’re used to doing performance optimization in most other languages, especially C, C++, and similar.  However, there are times when revisiting tricks learned in native code play a critical role in performance optimization in C#. I recently ran across a nasty scenario that illustrated to me how dangerous following any fixed rules for optimization can be… The rules in C# when optimizing code are very different than C or C++.  Often, they’re exactly backwards.  For example, in C and C++, lifting a variable out of loops in order to avoid memory allocations often can have huge advantages.  If some function within a call graph is allocating memory dynamically, and that gets called in a loop, it can dramatically slow down a routine. This can be a tricky bottleneck to track down, even with a profiler.  Looking at the memory allocation graph is usually the key for spotting this routine, as it’s often “hidden” deep in call graph.  For example, while optimizing some of my scientific routines, I ran into a situation where I had a loop similar to: for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i]); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This loop was at a fairly high level in the call graph, and often could take many hours to complete, depending on the input data.  As such, any performance optimization we could achieve would be greatly appreciated by our users. After a fair bit of profiling, I noticed that a couple of function calls down the call graph (inside of ProcessElement), there was some code that effectively was doing: // Allocate some data required DataStructure* data = new DataStructure(num); // Call into a subroutine that passed around and manipulated this data highly CallSubroutine(data); // Read and use some values from here double values = data->Foo; // Cleanup delete data; // ... return bar; Normally, if “DataStructure” was a simple data type, I could just allocate it on the stack.  However, it’s constructor, internally, allocated it’s own memory using new, so this wouldn’t eliminate the problem.  In this case, however, I could change the call signatures to allow the pointer to the data structure to be passed into ProcessElement and through the call graph, allowing the inner routine to reuse the same “data” memory instead of allocating.  At the highest level, my code effectively changed to something like: DataStructure* data = new DataStructure(numberToProcess); for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i], data); } delete data; Granted, this dramatically reduced the maintainability of the code, so it wasn’t something I wanted to do unless there was a significant benefit.  In this case, after profiling the new version, I found that it increased the overall performance dramatically – my main test case went from 35 minutes runtime down to 21 minutes.  This was such a significant improvement, I felt it was worth the reduction in maintainability. In C and C++, it’s generally a good idea (for performance) to: Reduce the number of memory allocations as much as possible, Use fewer, larger memory allocations instead of many smaller ones, and Allocate as high up the call stack as possible, and reuse memory I’ve seen many people try to make similar optimizations in C# code.  For good or bad, this is typically not a good idea.  The garbage collector in .NET completely changes the rules here. In C#, reallocating memory in a loop is not always a bad idea.  In this scenario, for example, I may have been much better off leaving the original code alone.  The reason for this is the garbage collector.  The GC in .NET is incredibly effective, and leaving the allocation deep inside the call stack has some huge advantages.  First and foremost, it tends to make the code more maintainable – passing around object references tends to couple the methods together more than necessary, and overall increase the complexity of the code.  This is something that should be avoided unless there is a significant reason.  Second, (unlike C and C++) memory allocation of a single object in C# is normally cheap and fast.  Finally, and most critically, there is a large advantage to having short lived objects.  If you lift a variable out of the loop and reuse the memory, its much more likely that object will get promoted to Gen1 (or worse, Gen2).  This can cause expensive compaction operations to be required, and also lead to (at least temporary) memory fragmentation as well as more costly collections later. As such, I’ve found that it’s often (though not always) faster to leave memory allocations where you’d naturally place them – deep inside of the call graph, inside of the loops.  This causes the objects to stay very short lived, which in turn increases the efficiency of the garbage collector, and can dramatically improve the overall performance of the routine as a whole. In C#, I tend to: Keep variable declarations in the tightest scope possible Declare and allocate objects at usage While this tends to cause some of the same goals (reducing unnecessary allocations, etc), the goal here is a bit different – it’s about keeping the objects rooted for as little time as possible in order to (attempt) to keep them completely in Gen0, or worst case, Gen1.  It also has the huge advantage of keeping the code very maintainable – objects are used and “released” as soon as possible, which keeps the code very clean.  It does, however, often have the side effect of causing more allocations to occur, but keeping the objects rooted for a much shorter time. Now – nowhere here am I suggesting that these rules are hard, fast rules that are always true.  That being said, my time spent optimizing over the years encourages me to naturally write code that follows the above guidelines, then profile and adjust as necessary.  In my current project, however, I ran across one of those nasty little pitfalls that’s something to keep in mind – interop changes the rules. In this case, I was dealing with an API that, internally, used some COM objects.  In this case, these COM objects were leading to native allocations (most likely C++) occurring in a loop deep in my call graph.  Even though I was writing nice, clean managed code, the normal managed code rules for performance no longer apply.  After profiling to find the bottleneck in my code, I realized that my inner loop, a innocuous looking block of C# code, was effectively causing a set of native memory allocations in every iteration.  This required going back to a “native programming” mindset for optimization.  Lifting these variables and reusing them took a 1:10 routine down to 0:20 – again, a very worthwhile improvement. Overall, the lessons here are: Always profile if you suspect a performance problem – don’t assume any rule is correct, or any code is efficient just because it looks like it should be Remember to check memory allocations when profiling, not just CPU cycles Interop scenarios often cause managed code to act very differently than “normal” managed code. Native code can be hidden very cleverly inside of managed wrappers

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• Developing Schema Compare for Oracle (Part 1)

  - by Simon Cooper

  SQL Compare is one of Red Gate's most successful SQL Server tools; it allows developers and DBAs to compare and synchronize the contents of their databases. Although similar tools exist for Oracle, they are quite noticeably lacking in the usability and stability that SQL Compare is known for in the SQL Server world. We could see a real need for a usable schema comparison tools for Oracle, and so the Schema Compare for Oracle project was born. Over the next few weeks, as we come up to release of v1, I'll be doing a series of posts on the development of Schema Compare for Oracle. For the first post, I thought I would start with the main pitfalls that we stumbled across when developing the product, especially from a SQL Server background. 1. Schemas and Databases The most obvious difference is that the concept of a 'database' is quite different between Oracle and SQL Server. On SQL Server, one server instance has multiple databases, each with separate schemas. There is typically little communication between separate databases, and most databases are no more than about 1000-2000 objects. This means SQL Compare can register an entire database in a reasonable amount of time, and cross-database dependencies probably won't be an issue. It is a quite different scene under Oracle, however. The terms 'database' and 'instance' are used interchangeably, (although technically 'database' refers to the datafiles on disk, and 'instance' the running Oracle process that reads & writes to the database), and a database is a single conceptual entity. This immediately presents problems, as it is infeasible to register an entire database as we do in SQL Compare; in my Oracle install, using the standard recommended options, there are 63975 system objects. If we tried to register all those, not only would it take hours, but the client would probably run out of memory before we finished. As a result, we had to allow people to specify what schemas they wanted to register. This decision had quite a few knock-on effects for the design, which I will cover in a future post. 2. Connecting to Oracle The next obvious difference is in actually connecting to Oracle – in SQL Server, you can specify a server and database, and off you go. On Oracle things are slightly more complicated. SIDs, Service Names, and TNS A database (the files on disk) must have a unique identifier for the databases on the system, called the SID. It also has a global database name, which consists of a name (which doesn't have to match the SID) and a domain. Alternatively, you can identify a database using a service name, which normally has a 1-to-1 relationship with instances, but may not if, for example, using RAC (Real Application Clusters) for redundancy and failover. You specify the computer and instance you want to connect to using TNS (Transparent Network Substrate). The user-visible parts are a config file (tnsnames.ora) on the client machine that specifies how to connect to an instance. For example, the entry for one of my test instances is: SC_11GDB1 = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = simonctest)(PORT = 1521)) ) (CONNECT_DATA = (SID = 11gR1db1) ) ) This gives the hostname, port, and SID of the instance I want to connect to, and associates it with a name (SC_11GDB1). The tnsnames syntax also allows you to specify failover, multiple descriptions and address lists, and client load balancing. You can then specify this TNS identifier as the data source in a connection string. Although using ODP.NET (the .NET dlls provided by Oracle) was fine for internal prototype builds, once we released the EAP we discovered that this simply wasn't an acceptable solution for installs on other people's machines. Due to .NET assembly strong naming, users had to have installed on their machines the exact same version of the ODP.NET dlls as we had on our build server. We couldn't ship the ODP.NET dlls with our installer as the Oracle license agreement prohibited this, and we didn't want to force users to install another Oracle client just so they can run our program. To be able to list the TNS entries in the connection dialog, we also had to locate and parse the tnsnames.ora file, which was complicated by users with several Oracle client installs and intricate TNS entries. After much swearing at our computers, we eventually decided to use a third party Oracle connection library from Devart that we could ship with our program; this could use whatever client version was installed, parse the TNS entries for us, and also had the nice feature of being able to connect to an Oracle server without having any client installed at all. Unfortunately, their current license agreement prevents us from shipping an Oracle SDK, but that's a bridge we'll cross when we get to it. 3. Running synchronization scripts The most important difference is that in Oracle, DDL is non-transactional; you cannot rollback DDL statements like you can on SQL Server. Although we considered various solutions to this, including using the flashback archive or recycle bin, or generating an undo script, no reliable method of completely undoing a half-executed sync script has yet been found; so in this case we simply have to trust that the DBA or developer will check and verify the script before running it. However, before we got to that stage, we had to get the scripts to run in the first place... To run a synchronization script from SQL Compare we essentially pass the script over to the SqlCommand.ExecuteNonQuery method. However, when we tried to do the same for an OracleConnection we got a very strange error – 'ORA-00911: invalid character', even when running the most basic CREATE TABLE command. After much hair-pulling and Googling, we discovered that Oracle has got some very strange behaviour with semicolons at the end of statements. To understand what's going on, we need to take a quick foray into SQL and PL/SQL. PL/SQL is not T-SQL In SQL Server, T-SQL is the language used to interface with the database. It has DDL, DML, control flow, and many other nice features (like Turing-completeness) that you can mix and match in the same script. In Oracle, DDL SQL and PL/SQL are two completely separate languages, with different syntax, different datatypes and different execution engines within the instance. Oracle SQL is much more like 'pure' ANSI SQL, with no state, no control flow, and only the basic DML commands. PL/SQL is the Turing-complete language, but can only do DML and DCL (i.e. BEGIN TRANSATION commands). Any DDL or SQL commands that aren't recognised by the PL/SQL engine have to be passed back to the SQL engine via an EXECUTE IMMEDIATE command. In PL/SQL, a semicolons is a valid token used to delimit the end of a statement. In SQL, a semicolon is not a valid token (even though the Oracle documentation gives them at the end of the syntax diagrams) . When you execute the command CREATE TABLE table1 (COL1 NUMBER); in SQL*Plus the semicolon on the end is a command to SQL*Plus to execute the preceding statement on the server; it strips off the semicolon before passing it on. SQL Developer does a similar thing. When executing a PL/SQL block, however, the syntax is like so: BEGIN INSERT INTO table1 VALUES (1); INSERT INTO table1 VALUES (2); END; / In this case, the semicolon is accepted by the PL/SQL engine as a statement delimiter, and instead the / is the command to SQL*Plus to execute the current block. This explains the ORA-00911 error we got when trying to run the CREATE TABLE command – the server is complaining about the semicolon on the end. This also means that there is no SQL syntax to execute more than one DDL command in the same OracleCommand. Therefore, we would have to do a round-trip to the server for every command we want to execute. Obviously, this would cause lots of network traffic and be very slow on slow or congested networks. Our first attempt at a solution was to wrap every SQL statement (without semicolon) inside an EXECUTE IMMEDIATE command in a PL/SQL block and pass that to the server to execute. One downside of this solution is that we get no feedback as to how the script execution is going; we're currently evaluating better solutions to this thorny issue. Next up: Dependencies; how we solved the problem of being unable to register the entire database, and the knock-on effects to the whole product.

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• Nginx Subdomain Problem

  - by user292299

  i can't access my subdomain on localhost. my localdomain is localhost.dev and it's work.but i want to auto subdomain for php script (username.localhost.dev) i try this server { listen 80 default_server; listen [::]:80 default_server ipv6only=on; access_log /var/www/access.log; error_log /var/www/error.log; root /var/www; index index.php index.html index.htm; # Make site accessible from http://localhost/ server_name localhost.dev ***.localhost.dev**; location / { # First attempt to serve request as file, then # as directory, then fall back to displaying a 404. try_files $uri $uri/ /index.html; # Uncomment to enable naxsi on this location # include /etc/nginx/naxsi.rules } location /f2/public/ { try_files $uri $uri/ /f2/public/index.php?$args; } location /doc/ { alias /usr/share/doc/; autoindex on; allow 127.0.0.1; allow ::1; deny all; } # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests #location /RequestDenied { # proxy_pass http://127.0.0.1:8080; #} #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # #error_page 500 502 503 504 /50x.html; #location = /50x.html { # root /usr/share/nginx/html; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { # fastcgi_split_path_info ^(.+\.php)(/.+)$; # # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini # # # With php5-cgi alone: # fastcgi_pass 127.0.0.1:9000; # # With php5-fpm: # fastcgi_pass unix:/var/run/php5-fpm.sock; # fastcgi_index index.php; # include fastcgi_params; include /etc/nginx/fastcgi_params; try_files $uri =404; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one # #location ~ /\.ht { # deny all; #} } it's not working.i change server_name for testing server_name localhost.dev asd.localhost.dev; i can't access asd.localhost.dev and i try this double server{} section # You may add here your # server { # ... # } # statements for each of your virtual hosts to this file ## # You should look at the following URL's in order to grasp a solid understanding # of Nginx configuration files in order to fully unleash the power of Nginx. # http://wiki.nginx.org/Pitfalls # http://wiki.nginx.org/QuickStart # http://wiki.nginx.org/Configuration # # Generally, you will want to move this file somewhere, and start with a clean # file but keep this around for reference. Or just disable in sites-enabled. # # Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples. ## server { listen 80 default_server; listen [::]:80 default_server ipv6only=on; access_log /var/www/access.log; error_log /var/www/error.log; root /var/www; index index.php index.html index.htm; # Make site accessible from http://localhost/ server_name localhost.dev; location / { # First attempt to serve request as file, then # as directory, then fall back to displaying a 404. try_files $uri $uri/ /index.html; # Uncomment to enable naxsi on this location # include /etc/nginx/naxsi.rules } location /f2/public/ { try_files $uri $uri/ /f2/public/index.php?$args; } location /doc/ { alias /usr/share/doc/; autoindex on; allow 127.0.0.1; allow ::1; deny all; } # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests #location /RequestDenied { # proxy_pass http://127.0.0.1:8080; #} #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # #error_page 500 502 503 504 /50x.html; #location = /50x.html { # root /usr/share/nginx/html; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { # fastcgi_split_path_info ^(.+\.php)(/.+)$; # # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini # # # With php5-cgi alone: # fastcgi_pass 127.0.0.1:9000; # # With php5-fpm: # fastcgi_pass unix:/var/run/php5-fpm.sock; # fastcgi_index index.php; # include fastcgi_params; include /etc/nginx/fastcgi_params; try_files $uri =404; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one # #location ~ /\.ht { # deny all; #} } ############################### server { access_log /var/www/access.log; error_log /var/www/error.log; root /var/www; index index.php index.html index.htm; # Make site accessible from http://localhost/ server_name asd.localhost.dev; location / { # First attempt to serve request as file, then # as directory, then fall back to displaying a 404. try_files $uri $uri/ /index.html; # Uncomment to enable naxsi on this location # include /etc/nginx/naxsi.rules } location /f2/public/ { try_files $uri $uri/ /f2/public/index.php?$args; } location /doc/ { alias /usr/share/doc/; autoindex on; allow 127.0.0.1; allow ::1; deny all; } # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests #location /RequestDenied { # proxy_pass http://127.0.0.1:8080; #} #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # #error_page 500 502 503 504 /50x.html; #location = /50x.html { # root /usr/share/nginx/html; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { # fastcgi_split_path_info ^(.+\.php)(/.+)$; # # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini # # # With php5-cgi alone: # fastcgi_pass 127.0.0.1:9000; # # With php5-fpm: # fastcgi_pass unix:/var/run/php5-fpm.sock; # fastcgi_index index.php; # include fastcgi_params; include /etc/nginx/fastcgi_params; try_files $uri =404; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one # #location ~ /\.ht { # deny all; #} } # another virtual host using mix of IP-, name-, and port-based configuration # #server { # listen 8000; # listen somename:8080; # server_name somename alias another.alias; # root html; # index index.html index.htm; # # location / { # try_files $uri $uri/ =404; # } #} # HTTPS server # #server { # listen 443; # server_name localhost; # # root html; # index index.html index.htm; # # ssl on; # ssl_certificate cert.pem; # ssl_certificate_key cert.key; # # ssl_session_timeout 5m; # # ssl_protocols SSLv3 TLSv1; # ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP; # ssl_prefer_server_ciphers on; # # location / { # try_files $uri $uri/ =404; # } #} i can't success

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• Set up linux box for hosting a-z

  - by microchasm

  I am in the process of reinstalling the OS on a machine that will be used to host a couple of apps for our business. The apps will be local only; access from external clients will be via vpn only. The prior setup used a hosting control panel (Plesk) for most of the admin, and I was looking at using another similar piece of software for the reinstall - but I figured I should finally learn how it all works. I can do most of the things the software would do for me, but am unclear on the symbiosis of it all. This is all an attempt to further distance myself from the land of Configuration Programmer/Programmer, if at all possible. I can't find a full walkthrough anywhere for what I'm looking for, so I thought I'd put up this question, and if people can help me on the way I will edit this with the answers, and document my progress/pitfalls. Hopefully someday this will help someone down the line. The details: CentOS 5.5 x86_64 httpd: Apache/2.2.3 mysql: 5.0.77 (to be upgraded) php: 5.1 (to be upgraded) The requirements: SECURITY!! Secure file transfer Secure client access (SSL Certs and CA) Secure data storage Virtualhosts/multiple subdomains Local email would be nice, but not critical The Steps: Download latest CentOS DVD-iso (torrent worked great for me). Install CentOS: While going through the install, I checked the Server Components option thinking I was going to be using another Plesk-like admin. In hindsight, considering I've decided to try to go my own way, this probably wasn't the best idea. Basic config: Setup users, networking/ip address etc. Yum update/upgrade. Upgrade PHP/MySQL: To upgrade PHP and MySQL to the latest versions, I had to look to another repo outside CentOS. IUS looks great and I'm happy I found it! Add IUS repository to our package manager cd /tmp wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/epel-release-1-1.ius.el5.noarch.rpm rpm -Uvh epel-release-1-1.ius.el5.noarch.rpm wget http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/x86_64/ius-release-1-4.ius.el5.noarch.rpm rpm -Uvh ius-release-1-4.ius.el5.noarch.rpm yum list | grep -w \.ius\. # list all the packages in the IUS repository; use this to find PHP/MySQL version and libraries you want to install Remove old version of PHP and install newer version from IUS rpm -qa | grep php # to list all of the installed php packages we want to remove yum shell # open an interactive yum shell remove php-common php-mysql php-cli #remove installed PHP components install php53 php53-mysql php53-cli php53-common #add packages you want transaction solve #important!! checks for dependencies transaction run #important!! does the actual installation of packages. [control+d] #exit yum shell php -v PHP 5.3.2 (cli) (built: Apr 6 2010 18:13:45) Upgrade MySQL from IUS repository /etc/init.d/mysqld stop rpm -qa | grep mysql # to see installed mysql packages yum shell remove mysql mysql-server #remove installed MySQL components install mysql51 mysql51-server mysql51-devel transaction solve #important!! checks for dependencies transaction run #important!! does the actual installation of packages. [control+d] #exit yum shell service mysqld start mysql -v Server version: 5.1.42-ius Distributed by The IUS Community Project Upgrade instructions courtesy of IUS wiki: http://wiki.iuscommunity.org/Doc/ClientUsageGuide Install rssh (restricted shell) to provide scp and sftp access, without allowing ssh login cd /tmp wget http://dag.wieers.com/rpm/packages/rssh/rssh-2.3.2-1.2.el5.rf.x86_64.rpm rpm -ivh rssh-2.3.2-1.2.el5.rf.x86_64.rpm useradd -m -d /home/dev -s /usr/bin/rssh dev passwd dev Edit /etc/rssh.conf to grant access to SFTP to rssh users. vi /etc/rssh.conf Uncomment or add: allowscp allowsftp This allows me to connect to the machine via SFTP protocol in Transmit (my FTP program of choice; I'm sure it's similar with other FTP apps). rssh instructions appropriated (with appreciation!) from http://www.cyberciti.biz/tips/linux-unix-restrict-shell-access-with-rssh.html Set up virtual interfaces ifconfig eth1:1 192.168.1.3 up #start up the virtual interface cd /etc/sysconfig/network-scripts/ cp ifcfg-eth1 ifcfg-eth1:1 #copy default script and match name to our virtual interface vi ifcfg-eth1:1 #modify eth1:1 script #ifcfg-eth1:1 | modify so it looks like this: DEVICE=eth1:1 IPADDR=192.168.1.3 NETMASK=255.255.255.0 NETWORK=192.168.1.0 ONBOOT=yes NAME=eth1:1 Add more Virtual interfaces as needed by repeating. Because of the ONBOOT=yes line in the ifcfg-eth1:1 file, this interface will be brought up when the system boots, or the network starts/restarts. service network restart Shutting down interface eth0: [ OK ] Shutting down interface eth1: [ OK ] Shutting down loopback interface: [ OK ] Bringing up loopback interface: [ OK ] Bringing up interface eth0: [ OK ] Bringing up interface eth1: [ OK ] ping 192.168.1.3 64 bytes from 192.168.1.3: icmp_seq=1 ttl=64 time=0.105 ms And this is where I'm at. I will keep editing this as I make progress. Any tips on how to Configure virtual interfaces/ip based virtual hosts for SSL, setting up a CA, or anything else would be appreciated.

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