Search Results

Search found 45013 results on 1801 pages for 'example'.

Page 325/1801 | < Previous Page | 321 322 323 324 325 326 327 328 329 330 331 332  | Next Page >

• Rotating WebLogic Server logs to avoid large files using WLST.

  - by adejuanc

  By default, when WebLogic Server instances are started in development mode, the server automatically renames (rotates) its local server log file as SERVER_NAME.log.n.  For the remainder of the server session, log messages accumulate in SERVER_NAME.log until the file grows to a size of 500 kilobytes.Each time the server log file reaches this size, the server renames the log file and creates a new SERVER_NAME.log to store new messages. By default, the rotated log files are numbered in order of creation filenamennnnn, where filename is the name configured for the log file. You can configure a server instance to include a time and date stamp in the file name of rotated log files; for example, server-name-%yyyy%-%mm%-%dd%-%hh%-%mm%.log.By default, when server instances are started in production mode, the server rotates its server log file whenever the file grows to 5000 kilobytes in size. It does not rotate the local server log file when the server is started. For more information about changing the mode in which a server starts, see Change to production mode in the Administration Console Online Help.You can change these default settings for log file rotation. For example, you can change the file size at which the server rotates the log file or you can configure a server to rotate log files based on a time interval. You can also specify the maximum number of rotated files that can accumulate. After the number of log files reaches this number, subsequent file rotations delete the oldest log file and create a new log file with the latest suffix.  Note: WebLogic Server sets a threshold size limit of 500 MB before it forces a hard rotation to prevent excessive log file growth. To Rotate via WLST : #invoke WLSTC:\>java weblogic.WLST#connect WLST to an Administration Serverawls:/offline> connect('username','password')#navigate to the ServerRuntime MBean hierarchywls:/mydomain/serverConfig> serverRuntime()wls:/mydomain/serverRuntime>ls()#navigate to the server LogRuntimeMBeanwls:/mydomain/serverRuntime> cd('LogRuntime/myserver')wls:/mydomain/serverRuntime/LogRuntime/myserver> ls()-r-- Name myserver-r-- Type LogRuntime-r-x forceLogRotation java.lang.Void :#force the immediate rotation of the server log filewls:/mydomain/serverRuntime/LogRuntime/myserver> cmo.forceLogRotation()wls:/mydomain/serverRuntime/LogRuntime/myserver> The server immediately rotates the file and prints the following message: <Mar 2, 2012 3:23:01 PM EST> <Info> <Log Management> <BEA-170017> <The log file C:\diablodomain\servers\myserver\logs\myserver.log will be rotated. Reopen the log file if tailing has stopped. This can happen on some platforms like Windows.><Mar 2, 2012 3:23:01 PM EST> <Info> <Log Management> <BEA-170018> <The log file has been rotated to C:\diablodomain\servers\myserver\logs\myserver.log00001. Log messages will continue to be logged in C:\diablodomain\servers\myserver\logs\myserver.log.> To specify the Location of the archived Log Files The following command specifies the directory location for the archived log files using the -Dweblogic.log.LogFileRotationDir Java startup option: java -Dweblogic.log.LogFileRotationDir=c:\foo-Dweblogic.management.username=installadministrator-Dweblogic.management.password=installadministrator weblogic.Server For more information read the following documentation ; Using the WebLogic Scripting Tool http://download.oracle.com/docs/cd/E13222_01/wls/docs103/config_scripting/using_WLST.html Configuring WebLogic Logging Services http://download.oracle.com/docs/cd/E12840_01/wls/docs103/logging/config_logs.html

  Read the article

• Advice on refactoring PHP Project

  - by b0x

  I have a small SAS ERP that was written some years ago using PHP. At that time, it didn't use any framework, but the code isn't a mess. Nowadays, the project grows and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such as Laravel. Although I'd love trying Laravel, I’m a small business and I don't have time nor money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers Separate the "view", in order to: release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) release different versions to fit mobile/tablet. Make different types of this product, selling packages as if they were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing routines for quality assurance. My current structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysql on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s files outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But I want to write a manual of our rules. Something that I can give to any new programmer at my company and he can go on. This is not totally a mess, but it could be better seeing the new practices. What could I do to separate this as MVC, to have multiple views. Could you give me some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc, would be nice.

  Read the article

• Refactoring existing PHP Project. I need some advices

  - by b0x

  i have a small SAS ERP that was written some years ago using PHP. At that time, it didn't used any framework, but the code isn't a mess as i will explain more detailed in the following lines. Nowadays, the project grow and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such Laravel. Although I'd love trying Laravel, I’m a small business and i don't have time/money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers I must separate the "view", because: I want to release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) Release different versions to fit mobile/tablet. Make different types of this product, seeling packages as if it were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing rotines, to quality assurance. My actual structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysqli on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s fies outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But i want to write a manual of our rules. Something that i can give to any new programmer at my companie and he can go on. This is not totally a mess, but It could be better seeing the new practices. What could I do to separate this as MVC, to have multiple VIEW’s. Could you gimme some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc. It would be nice. Thanks!

  Read the article

• Deliberate Practice

  - by Jeff Foster

  It’s easy to assume, as software engineers, that there is little need to “practice” writing code. After all, we write code all day long! Just by writing a little each day, we’re constantly learning and getting better, right? Unfortunately, that’s just not true. Of course, developers do improve with experience. Each time we encounter a problem we’re more likely to avoid it next time. If we’re in a team that deploys software early and often, we hone and improve the deployment process each time we practice it. However, not all practice makes perfect. To develop true expertise requires a particular type of practice, deliberate practice, the only goal of which is to make us better programmers. Everyday software development has other constraints and goals, not least the pressure to deliver. We rarely get the chance in the course of a “sprint” to experiment with potential solutions that are outside our current comfort zone. However, if we believe that software is a craft then it’s our duty to strive continuously to raise the standard of software development. This requires specific and sustained efforts to get better at something we currently can’t do well (from Harvard Business Review July/August 2007). One interesting way to introduce deliberate practice, in a sustainable way, is the code kata. The term kata derives from martial arts and refers to a set of movements practiced either solo or in pairs. One of the better-known examples is the Bowling Game kata by Bob Martin, the goal of which is simply to write some code to do the scoring for 10-pin bowling. It sounds too easy, right? What could we possibly learn from such a simple example? Trust me, though, that it’s not as simple as five minutes of typing and a solution. Of course, we can reach a solution in a short time, but the important thing about code katas is that we explore each technique fully and in a controlled way. We tackle the same problem multiple times, using different techniques and making different decisions, understanding the ramifications of each one, and exploring edge cases. The short feedback loop optimizes opportunities to learn. Another good example is Conway’s Game of Life. It’s a simple problem to solve, but try solving it in a functional style. If you’re used to mutability, solving the problem without mutating state will push you outside of your comfort zone. Similarly, if you try to solve it with the focus of “tell-don’t-ask“, how will the responsibilities of each object change? As software engineers, we don’t get enough opportunities to explore new ideas. In the middle of a development cycle, we can’t suddenly start experimenting on the team’s code base. Code katas offer an opportunity to explore new techniques in a safe environment. If you’re still skeptical, my challenge to you is simply to try it out. Convince a willing colleague to pair with you and work through a kata or two. It only takes an hour and I’m willing to bet you learn a few new things each time. The next step is to make it a sustainable team practice. Start with an hour every Friday afternoon (after all who wants to commit code to production just before they leave for the weekend?) for month and see how that works out. Finally, consider signing up for the Global Day of Code Retreat. It’s like a daylong code kata, it’s on December 8th and there’s probably an event in your area!

  Read the article

• How to define template directives (from an API perspective)?

  - by Ralph

  Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

  Read the article

• ORE graphics using Remote Desktop Protocol

  - by Sherry LaMonica

  Oracle R Enterprise graphics are returned as raster, or bitmap graphics. Raster images consist of tiny squares of color information referred to as pixels that form points of color to create a complete image. Plots that contain raster images render quickly in R and create small, high-quality exported image files in a wide variety of formats. However, it is a known issue that the rendering of raster images can be problematic when creating graphics using a Remote Desktop connection. Raster images do not display in the windows device using Remote Desktop under the default settings. This happens because Remote Desktop restricts the number of colors when connecting to a Windows machine to 16 bits per pixel, and interpolating raster graphics requires many colors, at least 32 bits per pixel.. For example, this simple embedded R image plot will be returned in a raster-based format using a standalone Windows machine:  R> library(ORE) R> ore.connect(user="rquser", sid="orcl", host="localhost", password="rquser", all=TRUE)  R> ore.doEval(function() image(volcano, col=terrain.colors(30))) Here, we first load the ORE packages and connect to the database instance using database login credentials. The ore.doEval function executes the R code within the database embedded R engine and returns the image back to the client R session. Over a Remote Desktop connection under the default settings, this graph will appear blank due to the restricted number of colors. Users who encounter this issue have two options to display ORE graphics over Remote Desktop: either raise Remote Desktop's Color Depth or direct the plot output to an alternate device. Option #1: Raise Remote Desktop Color Depth setting In a Remote Desktop session, all environment variables, including display variables determining Color Depth, are determined by the RCP-Tcp connection settings. For example, users can reduce the Color Depth when connecting over a slow connection. The different settings are 15 bits, 16 bits, 24 bits, or 32 bits per pixel. To raise the Remote Desktop color depth: On the Windows server, launch Remote Desktop Session Host Configuration from the Accessories menu.Under Connections, right click on RDP-Tcp and select Properties.On the Client Settings tab either uncheck LimitMaximum Color Depth or set it to 32 bits per pixel. Click Apply, then OK, log out of the remote session and reconnect.After reconnecting, the Color Depth on the Display tab will be set to 32 bits per pixel.  Raster graphics will now display as expected. For ORE users, the increased color depth results in slightly reduced performance during plot creation, but the graph will be created instead of displaying an empty plot. Option #2: Direct plot output to alternate device Plotting to a non-windows device is a good option if it's not possible to increase Remote Desktop Color Depth, or if performance is degraded when creating the graph. Several device drivers are available for off-screen graphics in R, such as postscript, pdf, and png. On-screen devices include windows, X11 and Cairo. Here we output to the Cairo device to render an on-screen raster graphic.  The grid.raster function in the grid package is analogous to other grid graphical primitives - it draws a raster image within the current plot's grid.  R> options(device = "CairoWin") # use Cairo device for plotting during the session R> library(Cairo) # load Cairo, grid and png libraries  R> library(grid) R> library(png)  R> res <- ore.doEval(function()image(volcano,col=terrain.colors(30))) # create embedded R plot  R> img <- ore.pull(res, graphics = TRUE)$img[[1]] # extract image  R> grid.raster(as.raster(readPNG(img)), interpolate = FALSE) # generate raster graph R> dev.off() # turn off first device   By default, the interpolate argument to grid.raster is TRUE, which means that what is actually drawn by R is a linear interpolation of the pixels in the original image. Setting interpolate to FALSE uses a sample from the pixels in the original image.A list of graphics devices available in R can be found in the Devices help file from the grDevices package: R> help(Devices)

  Read the article

• Design Pattern for building a Budget

  - by Scott

  So I've looked at the Builder Pattern, Abstract Interfaces, other design patterns, etc. - and I think I'm over thinking the simplicity behind what I'm trying to do, so I'm asking you guys for some help with either recommending a design pattern I should use, or an architecture style I'm not familiar with that fits my task. So I have one model that represents a Budget in my code. At a high level, it looks like this: public class Budget { public int Id { get; set; } public List<MonthlySummary> Months { get; set; } public float SavingsPriority { get; set; } public float DebtPriority { get; set; } public List<Savings> SavingsCollection { get; set; } public UserProjectionParameters UserProjectionParameters { get; set; } public List<Debt> DebtCollection { get; set; } public string Name { get; set; } public List<Expense> Expenses { get; set; } public List<Income> IncomeCollection { get; set; } public bool AutoSave { get; set; } public decimal AutoSaveAmount { get; set; } public FundType AutoSaveType { get; set; } public decimal TotalExcess { get; set; } public decimal AccountMinimum { get; set; } } To go into more detail about some of the properties here shouldn't be necessary, but if you have any questions about those I will fill more out for you guys. Now, I'm trying to create code that builds one of these things based on a set of BudgetBuildParameters that the user will create and supply. There are going to be multiple types of these parameters. For example, on the sites homepage, there will be an example section where you can quickly see what your numbers look like, so they would be a much simpler set of SampleBudgetBuildParameters then say after a user registers and wants to create a fully filled out Budget using much more information in the DebtBudgetBuildParameters. Now a lot of these builds are going to be using similar code for certain tasks, but might want to also check the status of a users DebtCollection when formulating a monthly spending report, where as a Budget that only focuses on savings might not want to. I'd like to reduce code duplication (obviously) as much as possible, but in my head, every way I can think to do this would require using a base BudgetBuilderFactory to return the correct builder to the caller, and then creating say a SimpleBudgetBuilder that inherits from a BudgetBuilder, and put all duplicate code in the BudgetBuilder, and let the SimpleBudgetBuilder handle it's own cases. Problem is, a lot of the unique cases are unique to 2/4 builders, so there will be duplicate code somewhere in there obviously if I did that. Can anyone think of a better way to either explain a solution to this that may or may not be similar to mine, or a completely different pattern or way of thinking here? I really appreciate it.

  Read the article

• Introducing the Oracle Linux Playground yum repo

  - by wcoekaer

  We just introduced a new yum repository/channel on http://public-yum.oracle.com called the playground channel. What we started doing is the following: When a new stable mainline kernel is released by Linus or GregKH, we internally build RPMs to test it and do some QA work around it to keep track of what's going on with the latest development kernels. It helps us understand how performance moves up or down and if there are issues, we try to help look into them and of course send that stuff back upstream. Many Linux users out there are interested in trying out the latest features but there are some potential barriers to do this. (1) in general, you are looking at an upstream development distribution, which means that everything changes both in userspace(random applications) and kernel. Projects like Fedora are very useful and someone that wants to just see how the entire distribution evolves with all the changes, this is a great way to be current. A drawback here, though, is that if you have applications that are not part of the distribution, there's a lot of manual work involved or they might just not work because the changes are too drastic. The introduction of systemd is a good example. (2) when you look at many of our customers, that are interested in our database products or applications, the starting point of having a supported/certified userspace/distribution, like Oracle Linux, is a much easier way to get your feet wet in seeing what new/future Linux kernel enhancements could do. This is where the playground channel comes into play. When you install Oracle Linux 6 (which anyone can download and use from http://edelivery.oracle.com/linux), grab the latest public yum repository file http://public-yum.oracle.com/public-yum-ol6.repo, put it in /etc/yum.repos.d and enable the playground repo : [ol6_playground_latest] name=Latest mainline stable kernel for Oracle Linux 6 ($basearch) - Unsupported baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL6/playground/latest/$basearch/ gpgkey=http://public-yum.oracle.com/RPM-GPG-KEY-oracle-ol6 gpgcheck=1 enabled=1 Now, all you need to do : type yum update and you will be downloading the latest stable kernel which will install cleanly on Oracle Linux 6. Thus you end up with a stable Linux distribution where you can install all your software, and then download the latest stable kernel (at time of writing this is 3.6.7) without having to recompile a kernel, without having to jump through hoops. There is of course a big, very important disclaimer this is NOT for PRODUCTION use. We want to try and help make it easy for people that are interested, from a user perspective, where the Linux kernel is going and make it easy to install and use it and play around with new features. Without having to learn how to compile a kernel and without necessarily having to install a complete new distribution with all the changes top to bottom. So we don't or won't introduce any new userspace changes, this project really is around making it easy to try out the latest upstream Linux kernels in a very easy way on an environment that's stable and you can keep current, since all the latest errata for Oracle Linux 6 are published on the public yum repo as well. So one repository location for all your current changes and the upstream kernels. We hope that this will get more users to try out the latest kernel and report their findings. We are always interested in understanding stability and performance characteristics. As new features are going into the mainline kernel, that could potentially be interesting or useful for various products, we will try to point them out on our blogs and give an example on how something can be used so you can try it out for yourselves. Anyway, I hope people will find this useful and that it will help increase interested in upstream development beyond reading lkml by some of the more non-kernel-developer types.

  Read the article

• Fast Data - Big Data's achilles heel

  - by thegreeneman

  At OOW 2013 in Mark Hurd and Thomas Kurian's keynote, they discussed Oracle's Fast Data software solution stack and discussed a number of customers deploying Oracle's Big Data / Fast Data solutions and in particular Oracle's NoSQL Database.  Since that time, there have been a large number of request seeking clarification on how the Fast Data software stack works together to deliver on the promise of real-time Big Data solutions.   Fast Data is a software solution stack that deals with one aspect of Big Data, high velocity.   The software in the Fast Data solution stack involves 3 key pieces and their integration:  Oracle Event Processing, Oracle Coherence, Oracle NoSQL Database.   All three of these technologies address a high throughput, low latency data management requirement.   Oracle Event Processing enables continuous query to filter the Big Data fire hose, enable intelligent chained events to real-time service invocation and augments the data stream to provide Big Data enrichment. Extended SQL syntax allows the definition of sliding windows of time to allow SQL statements to look for triggers on events like breach of weighted moving average on a real-time data stream.    Oracle Coherence is a distributed, grid caching solution which is used to provide very low latency access to cached data when the data is too big to fit into a single process, so it is spread around in a grid architecture to provide memory latency speed access.  It also has some special capabilities to deploy remote behavioral execution for "near data" processing.   The Oracle NoSQL Database is designed to ingest simple key-value data at a controlled throughput rate while providing data redundancy in a cluster to facilitate highly concurrent low latency reads.  For example, when large sensor networks are generating data that need to be captured while analysts are simultaneously extracting the data using range based queries for upstream analytics.  Another example might be storing cookies from user web sessions for ultra low latency user profile management, also leveraging that data using holistic MapReduce operations with your Hadoop cluster to do segmented site analysis.  Understand how NoSQL plays a critical role in Big Data capture and enrichment while simultaneously providing a low latency and scalable data management infrastructure thru clustered, always on, parallel processing in a shared nothing architecture. Learn how easily a NoSQL cluster can be deployed to provide essential services in industry specific Fast Data solutions. See these technologies work together in a demonstration highlighting the salient features of these Fast Data enabling technologies in a location based personalization service. The question then becomes how do these things work together to deliver an end to end Fast Data solution.  The answer is that while different applications will exhibit unique requirements that may drive the need for one or the other of these technologies, often when it comes to Big Data you may need to use them together.   You may have the need for the memory latencies of the Coherence cache, but just have too much data to cache, so you use a combination of Coherence and Oracle NoSQL to handle extreme speed cache overflow and retrieval.   Here is a great reference to how these two technologies are integrated and work together.  Coherence & Oracle NoSQL Database.   On the stream processing side, it is similar as with the Coherence case.  As your sliding windows get larger, holding all the data in the stream can become difficult and out of band data may need to be offloaded into persistent storage.  OEP needs an extreme speed database like Oracle NoSQL Database to help it continue to perform for the real time loop while dealing with persistent spill in the data stream.  Here is a great resource to learn more about how OEP and Oracle NoSQL Database are integrated and work together.  OEP & Oracle NoSQL Database.

  Read the article

• How to automate a monitoring system for ETL runs

  - by Jeffrey McDaniel

  Upon completion of the Primavera ETL process there are a few ways to determine if the process finished successfully.  First, in the <installation directory>\log folder,  there is a staretlprocess.log and staretl.html files. These files will give the output results of the ETL run. The staretl.html file will give a detailed summary of each step of the process, its run time, and its status. The .log file, based on the logging level set in the Configuration tool, can give extensive information about the ETL process. The log file can be used as a validation for process completion.  To automate the monitoring of these log files, perform the following steps: 1. Write a custom application to parse through the log file and search for [ERROR] . In most cases,  a major [ERROR] could cause the ETL process to fail. Searching the log and finding this value is worthy of an alert. 2. Determine the total number of steps in the ETL process, and validate that the log file recorded and entry for the final step.  For example validate that your log file contains an entry for Step 39/39 (could be different based on the version you are running). If there is no Step 39/39, then either the process is taking longer than expected or it didn't make it to the end.  Either way this would be a good cause for an alert. 3. Check the last line in the log file. The last line of the log file should contain an indication that the ETL run completed successfully. For example, the last line of a log file will say (results could be different based on Reporting Database versions):   [INFO] (Message) Finished Writing Report 4. You could write an Ant script to execute the ETL process and have it set to - failonerror="true" - and from there send results to an external tool to monitor the jobs, send to email, or send to database. With each ETL run, the log file appends to the existing log file by default. Because of this behavior, I would recommend renaming the existing log files before running a new ETL process. By doing this,  only log entries for the currently running ETL process is recorded in the new log files. Based on these log entries, alerts can be setup to notify the administrator or DBA. Another way to determine if the ETL process has completed successfully is to monitor the etl_processmaster table.  Depending on the Reporting Database version this could be in the Stage or Star databases. As of Reporting Database 2.2 and higher this would be in the Star database.  The etl_processmaster table records entries for the ETL run along with a Start and Finish time.  If the ETl process has failed the Finish date should be null. This table can be queried at a time when ETL process is expected to be finished and if null send an alert.  These are just some options. There are additional ways this can be accomplished based around these two areas - log files or database. Here is an additional query to gather more information about your ETL run (connect as Staruser): SELECT SYSDATE,test_script,decode(loc, 0, PROCESSNAME, trim(SUBSTR(PROCESSNAME, loc+1))) PROCESSNAME ,duration duration from ( select (e.endtime - b.starttime) * 1440 duration, to_char(b.starttime, 'hh24:mi:ss') starttime, to_char(e.endtime, 'hh24:mi:ss') endtime,  b.PROCESSNAME, instr(b.PROCESSNAME, ']') loc, b.infotype test_script from ( select processid, infodate starttime, PROCESSNAME, INFOMSG, INFOTYPE from etl_processinfo  where processid = (select max(PROCESSID) from etl_processinfo) and infotype = 'BEGIN' ) b  inner Join ( select processid, infodate endtime, PROCESSNAME, INFOMSG, INFOTYPE from etl_processinfo  where processid = (select max(PROCESSID) from etl_processinfo) and infotype = 'END' ) e on b.processid = e.processid  and b.PROCESSNAME = e.PROCESSNAME order by b.starttime)

  Read the article

• Observing flow control idle time in TCP

  - by user12820842

  Previously I described how to observe congestion control strategies during transmission, and here I talked about TCP's sliding window approach for handling flow control on the receive side. A neat trick would now be to put the pieces together and ask the following question - how often is TCP transmission blocked by congestion control (send-side flow control) versus a zero-sized send window (which is the receiver saying it cannot process any more data)? So in effect we are asking whether the size of the receive window of the peer or the congestion control strategy may be sub-optimal. The result of such a problem would be that we have TCP data that we could be transmitting but we are not, potentially effecting throughput. So flow control is in effect: when the congestion window is less than or equal to the amount of bytes outstanding on the connection. We can derive this from args[3]-tcps_snxt - args[3]-tcps_suna, i.e. the difference between the next sequence number to send and the lowest unacknowledged sequence number; and when the window in the TCP segment received is advertised as 0 We time from these events until we send new data (i.e. args[4]-tcp_seq = snxt value when window closes. Here's the script: #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[3]-tcps_snxt - args[3]-tcps_suna) = args[3]-tcps_cwnd / { cwndclosed[args[1]-cs_cid] = timestamp; cwndsnxt[args[1]-cs_cid] = args[3]-tcps_snxt; @numclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } tcp:::send / cwndclosed[args[1]-cs_cid] && args[4]-tcp_seq = cwndsnxt[args[1]-cs_cid] / { @meantimeclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = avg(timestamp - cwndclosed[args[1]-cs_cid]); @stddevtimeclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = stddev(timestamp - cwndclosed[args[1]-cs_cid]); @numclosed["cwnd", args[2]-ip_daddr, args[4]-tcp_dport] = count(); cwndclosed[args[1]-cs_cid] = 0; cwndsnxt[args[1]-cs_cid] = 0; } tcp:::receive / args[4]-tcp_window == 0 && (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { swndclosed[args[1]-cs_cid] = timestamp; swndsnxt[args[1]-cs_cid] = args[3]-tcps_snxt; @numclosed["swnd", args[2]-ip_saddr, args[4]-tcp_dport] = count(); } tcp:::send / swndclosed[args[1]-cs_cid] && args[4]-tcp_seq = swndsnxt[args[1]-cs_cid] / { @meantimeclosed["swnd", args[2]-ip_daddr, args[4]-tcp_sport] = avg(timestamp - swndclosed[args[1]-cs_cid]); @stddevtimeclosed["swnd", args[2]-ip_daddr, args[4]-tcp_sport] = stddev(timestamp - swndclosed[args[1]-cs_cid]); swndclosed[args[1]-cs_cid] = 0; swndsnxt[args[1]-cs_cid] = 0; } END { printf("%-6s %-20s %-8s %-25s %-8s %-8s\n", "Window", "Remote host", "Port", "TCP Avg WndClosed(ns)", "StdDev", "Num"); printa("%-6s %-20s %-8d %@-25d %@-8d %@-8d\n", @meantimeclosed, @stddevtimeclosed, @numclosed); } So this script will show us whether the peer's receive window size is preventing flow ("swnd" events) or whether congestion control is limiting flow ("cwnd" events). As an example I traced on a server with a large file transfer in progress via a webserver and with an active ssh connection running "find / -depth -print". Here is the output: ^C Window Remote host Port TCP Avg WndClosed(ns) StdDev Num cwnd 10.175.96.92 80 86064329 77311705 125 cwnd 10.175.96.92 22 122068522 151039669 81 So we see in this case, the congestion window closes 125 times for port 80 connections and 81 times for ssh. The average time the window is closed is 0.086sec for port 80 and 0.12sec for port 22. So if you wish to change congestion control algorithm in Oracle Solaris 11, a useful step may be to see if congestion really is an issue on your network. Scripts like the one posted above can help assess this, but it's worth reiterating that if congestion control is occuring, that's not necessarily a problem that needs fixing. Recall that congestion control is about controlling flow to prevent large-scale drops, so looking at congestion events in isolation doesn't tell us the whole story. For example, are we seeing more congestion events with one control algorithm, but more drops/retransmission with another? As always, it's best to start with measures of throughput and latency before arriving at a specific hypothesis such as "my congestion control algorithm is sub-optimal".

  Read the article

• News From EAP Testing

  - by Fatherjack

  There is a phrase that goes something like “Watch the pennies and the pounds/dollars will take care of themselves”, meaning that if you pay attention to the small things then the larger things are going to fare well too. I am lucky enough to be a Friend of Red Gate and once in a while I get told about new features in their tools and have a test copy of the software to trial. I got one of those emails a week or so ago and I have been exploring the SQL Prompt 6 EAP since then. One really useful feature of long standing in SQL Prompt is the idea of a code snippet that is automatically pasted into the SSMS editor when you type a few key letters. For example I can type “ssf” and then press the tab key and the text is expanded to SELECT * FROM. There are lots of these combinations and it is possible to create your own really easily. To create your own you use the Snippet Manager interface to define the shortcut letters and the code that you want to have put in their place. Let’s look at an example. Say I am writing a blog about something and want to have the demo code create a temporary table. It might looks like this; The first time you run the code everything is fine, a lovely set of dates fill the results grid but run it a second time and this happens.   Yep, we didn’t destroy the temporary table so the CREATE statement fails when it finds the table already exists. No matter, I have a snippet created that takes care of this.   Nothing too technical here but you will see that in the Code section there is $CURSOR$, this isn’t a TSQL keyword but a marker for SQL Prompt to place the cursor in that position when the Code is pasted into the SSMS Editor. I just place my cursor above the CREATE statement and type “ifobj” – the shortcut for my code to DROP the temporary table – which has been defined in the Snippet Manager as below. This means I am right-away ready to type the name of the offending table. Pretty neat and it’s been very useful in saving me lots of time over many years.   The news for SQL Prompt 6 is that Red Gate have added a new Snippet Command of $PASTE$. Let’s alter our snippet to the following and try it out   Once again, we will type type “ifobj” in the SSMS Editor but first of all, highlight the name of the table #TestTable and copy it to your clipboard. Now type “ifobj” and press Tab… Wherever the string $PASTE$ is placed in the snippet, the contents of your clipboard are merged into the pasted TSQL. This means I don’t need to type the table name into the code snippet, it’s already there and I am seeing a fully functioning piece of TSQL ready to run. This means it is it even easier to write TSQL quickly and consistently. Attention to detail like this from Red Gate means that their developer tools stay on track to keep winning awards year after year and help take the hard work out of writing neat, accurate TSQL. If you want to try out SQL Prompt all the details are at http://www.red-gate.com/products/sql-development/sql-prompt/.

  Read the article

• Approach for packing 2D shapes while minimizing total enclosing area

  - by Dennis

  Not sure on my tags for this question, but in short .... I need to solve a problem of packing industrial parts into crates while minimizing total containing area. These parts are motors, or pumps, or custom-made components, and they have quite unusual shapes. For some, it may be possible to assume that a part === rectangular cuboid, but some are not so simple, i.e. they assume a shape more of that of a hammer or letter T. With those, (assuming 2D shape), by alternating direction of top & bottom, one can pack more objects into the same space, than if all tops were in the same direction. Crude example below with letter "T"-shaped parts: ***** xxxxx ***** x ***** *** ooo * x vs * x vs * x vs * x o * x * xxxxx * x * x o xxxxx xxx Right now we are solving the problem by something like this: using CAD software, make actual models of how things fit in crate boxes make estimates of actual crate dimensions & write them into Excel file (1) is crazy amount of work and as the result we have just a limited amount of possible entries in (2), the Excel file. The good things is that programming this is relatively easy. Given a combination of products to go into crates, we do a lookup, and if entry exists in the Excel (or Database), we bring it out. If it doesn't, we say "sorry, no data!". I don't necessarily want to go full force on making up some crazy algorithm that given geometrical part description can align, rotate, and figure out best part packing into a crate, given its shape, but maybe I do.. Question Well, here is my question: assuming that I can represent my parts as 2D (to be determined how), and that some parts look like letter T, and some parts look like rectangles, which algorithm can I use to give me a good estimate on the dimensions of the encompassing area, while ensuring that the parts are packed in a minimal possible area, to minimize crating/shipping costs? Are there approximation algorithms? Seeing how this can get complex, is there an existing library I could use? My thought / Approach My naive approach would be to define a way to describe position of parts, and place the first part, compute total enclosing area & dimensions. Then place 2nd part in 0 degree orientation, repeat, place it at 180 degree orientation, repeat (for my case I don't think 90 degree rotations will be meaningful due to long lengths of parts). Proceed using brute force "tacking on" other parts to the enclosing area until all parts are processed. I may have to shift some parts a tad (see 3rd pictorial example above with letters T). This adds a layer of 2D complexity rather than 1D. I am not sure how to approach this. One idea I have is genetic algorithms, but I think those will take up too much processing power and time. I will need to look out for shape collisions, as well as adding extra padding space, since we are talking about real parts with irregularities rather than perfect imaginary blocks. I'm afraid this can get geometrically messy fairly fast, and I'd rather keep things simple, if I can. But what if the best (practical) solution is to pack things into different crate boxes rather than just one? This can get a bit more tricky. There is human element involved as well, i.e. like parts can go into same box and are thus a constraint to be considered. Some parts that are not the same are sometimes grouped together for shipping and can be considered as a common grouped item. Sometimes customers want things shipped their way, which adds human element to constraints. so there will have to be some customization.

  Read the article

• What common interface would be appropriate for these game object classes?

  - by Jefffrey

  Question A component based system's goal is to solve the problems that derives from inheritance: for example the fact that some parts of the code (that are called components) are reused by very different classes that, hypothetically, would lie in a very different branch of the inheritance tree. That's a very nice concept, but I've found out that CBS is often hard to accomplish without using ugly hacks. Implementations of this system are often far from clean. But I don't want to discuss this any further. My question is: how can I solve the same problems a CBS try to solve with a very clean interface? (possibly with examples, there are a lot of abstract talks about the "perfect" design already). Context Here's an example I was going for before realizing I was just reinventing inheritance again: class Human { public: Position position; Movement movement; Sprite sprite; // other human specific components }; class Zombie { Position position; Movement movement; Sprite sprite; // other zombie specific components }; After writing that I realized I needed an interface, otherwise I would have needed N containers for N different types of objects (or to use boost::variant to gather them all together). So I've thought of polymorphism (move what systems do in a CBS design into class specific functions): class Entity { public: virtual void on_event(Event) {} // not pure virtual on purpose virtual void on_update(World) {} virtual void on_draw(Window) {} }; class Human : public Entity { private: Position position; Movement movement; Sprite sprite; public: virtual void on_event(Event) { ... } virtual void on_update(World) { ... } virtual void on_draw(Window) { ... } }; class Zombie : public Entity { private: Position position; Movement movement; Sprite sprite; public: virtual void on_event(Event) { ... } virtual void on_update(World) { ... } virtual void on_draw(Window) { ... } }; Which was nice, except for the fact that now the outside world would not even be able to know where a Human is positioned (it does not have access to its position member). That would be useful to track the player position for collision detection or if on_update the Zombie would want to track down its nearest human to move towards him. So I added const Position& get_position() const; to both the Zombie and Human classes. And then I realized that both functionality were shared, so it should have gone to the common base class: Entity. Do you notice anything? Yes, with that methodology I would have a god Entity class full of common functionality (which is the thing I was trying to avoid in the first place). Meaning of "hacks" in the implementation I'm referring to I'm talking about the implementations that defines Entities as simple IDs to which components are dynamically attached. Their implementation can vary from C-stylish: int last_id; Position* positions[MAX_ENTITIES]; Movement* movements[MAX_ENTITIES]; Where positions[i], movements[i], component[i], ... make up the entity. Or to more C++-style: int last_id; std::map<int, Position> positions; std::map<int, Movement> movements; From which systems can detect if an entity/id can have attached components.

  Read the article

• [EF + ORACLE] Updating and Deleting Entities

  - by JTorrecilla

  Prologue In previous chapters we have seen how to insert data through EF, with and without sequences. In this one, we are going to see how to Update and delete Data from the DB. Updating data The update of the Entity Data (properties) is a very common and easy action. Before of change any of the properties of the Entity, we can check the EntityState property, and we can see that is EntityState.Unchanged.   For making an update it is needed to get the Entity which will be modified. In the following example, I use the GetEmployeeByNumber to get a valid Entity: 1: EMPLEADOS emp=GetEmployeeByNumber(2); 2: emp.Name="a"; 3: emp.Phone="2"; 4: emp.Mail="aa"; After modifying the desired properties of the Entity, we are going to check again Entitystate property, which now has the EntityState.Modified value. To persist the changes to the DB is necessary to invoke the SaveChanges function of our context. 1: context.SaveChanges(); After modifying the desired properties of the Entity, we are going to check again Entitystate property, which now has the EntityState.Modified value. To persist the changes to the DB is necessary to invoke the SaveChanges function of our context. If we check again the EntityState property we will see that the value will be EntityState.Unchanged.   Deleting Data Another easy action is to delete an Entity.   The first step to delete an Entity from the DB is to select the entity: 1: CLIENTS selectedClient = GetClientByNumber(15); 2: context.CLIENTES.DeleteObject(clienteSeleccionado); Before invoking the DeleteObject function, we will check EntityStet which value must be EntityState.Unchanged. After deleting the object, the state will be changed to EntitySate.Deleted. To commit the action we have to invoke the SaveChanges function. Aftar that, the EntityState property will be EntityState.Detached. Cascade Entity Framework lets cascade updates and deletes, although I never see cascade updates. What is a cascade delete? A cascade delete is an action that allows to delete all the related object to the object we desire to delete. This option could be established in the DB manager, or it could be in the EF model designer. For example: With a given relation (1-N) between clients and requests. The common situation must be to let delete those clients whose have no requests. If we select the relation between both entities, and press the second mouse button, we can see the properties panel of the relation. The props are: This grid shows the relations indicating the Master table(Clients) and the end point (Cabecera or Requests) The property “End 1 OnDelete” indicates the action to do when a Entity from the Master will be deleted. There are two options: - None: No action will be done, it is said, if a Entity has details entities it could not be deleted. - Cascade: It will delete all related entities to the master Entity. If we enable the cascade delete in a relation, and we invoke the DeleteObject function of the set, we could observe that all the related object indicates a Entitystate.Deleted state. Like an update, insert or common delete, until we commit the changes with SaveChanges function, the data would not be commited. Si habilitamos el borrado en cascada de una relación, e invocamos a la función DeleteObject del conjunto, podremos observar que todas las entidades de Detalle (de la relación indicada) presentan el valor EntityState.Deleted en la propiedad EntityState. Del mismo modo que en el borrado, inserción o actualización, hasta que no se invoque al método SaveChanges, los cambios no van a ser confirmados en la Base de Datos. Finally In this chapter we have seen how to update a Entity, how to delete an Entity and how to implement Cascade Deleting through EF. In next chapters we will see how to query the DB data.

  Read the article

• C# 5 Async, Part 3: Preparing Existing code For Await

  - by Reed

  While the Visual Studio Async CTP provides a fantastic model for asynchronous programming, it requires code to be implemented in terms of Task and Task<T>.  The CTP adds support for Task-based asynchrony to the .NET Framework methods, and promises to have these implemented directly in the framework in the future.  However, existing code outside the framework will need to be converted to using the Task class prior to being usable via the CTP. Wrapping existing asynchronous code into a Task or Task<T> is, thankfully, fairly straightforward.  There are two main approaches to this. Code written using the Asynchronous Programming Model (APM) is very easy to convert to using Task<T>.  The TaskFactory class provides the tools to directly convert APM code into a method returning a Task<T>.  This is done via the FromAsync method.  This method takes the BeginOperation and EndOperation methods, as well as any parameters and state objects as arguments, and returns a Task<T> directly. For example, we could easily convert the WebRequest BeginGetResponse and EndGetResponse methods into a method which returns a Task<WebResponse> via: Task<WebResponse> task = Task.Factory .FromAsync<WebResponse>( request.BeginGetResponse, request.EndGetResponse, null); .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; } Event-based Asynchronous Pattern (EAP) code can also be wrapped into a Task<T>, though this requires a bit more effort than the one line of code above.  This is handled via the TaskCompletionSource<T> class.  MSDN provides a detailed example of using this to wrap an EAP operation into a method returning Task<T>.  It demonstrates handling cancellation and exception handling as well as the basic operation of the asynchronous method itself. The basic form of this operation is typically: Task<YourResult> GetResultAsync() { var tcs = new TaskCompletionSource<YourResult>(); // Handle the event, and setup the task results... this.GetResultCompleted += (o,e) => { if (e.Error != null) tcs.TrySetException(e.Error); else if (e.Cancelled) tcs.TrySetCanceled(); else tcs.TrySetResult(e.Result); }; // Call the asynchronous method this.GetResult(); // Return the task from the TaskCompletionSource return tcs.Task; } We can easily use these methods to wrap our own code into a method that returns a Task<T>.  Existing libraries which cannot be edited can be extended via Extension methods.  The CTP uses this technique to add appropriate methods throughout the framework. The suggested naming for these methods is to define these methods as “Task<YourResult> YourClass.YourOperationAsync(…)”.  However, this naming often conflicts with the default naming of the EAP.  If this is the case, the CTP has standardized on using “Task<YourResult> YourClass.YourOperationTaskAsync(…)”. Once we’ve wrapped all of our existing code into operations that return Task<T>, we can begin investigating how the Async CTP can be used with our own code.

  Read the article

• We have our standards, and we need them

  - by Tony Davis

  The presenter suddenly broke off. He was midway through his section on how to apply to the relational database the Continuous Delivery techniques that allowed for rapid-fire rounds of development and refactoring, while always retaining a “production-ready” state. He sighed deeply and then launched into an astonishing diatribe against Database Administrators, much of his frustration directed toward Oracle DBAs, in particular. In broad strokes, he painted the picture of a brave new deployment philosophy being frustratingly shackled by the relational database, and by especially by the attitudes of the guardians of these databases. DBAs, he said, shunned change and “still favored tools I’d have been embarrassed to use in the ’80′s“. DBAs, Oracle DBAs especially, were more attached to their vendor than to their employer, since the former was the primary source of their career longevity and spectacular remuneration. He contended that someone could produce the best IDE or tool in the world for Oracle DBAs and yet none of them would give a stuff, unless it happened to come from the “mother ship”. I sat blinking in astonishment at the speaker’s vehemence, and glanced around nervously. Nobody in the audience disagreed, and a few nodded in assent. Although the primary target of the outburst was the Oracle DBA, it made me wonder. Are we who work with SQL Server, database professionals or merely SQL Server fanbois? Do DBAs, in general, have an image problem? Is it a good career-move to be seen to be holding onto a particular product by the whites of our knuckles, to the exclusion of all else? If we seek a broad, open-minded, knowledge of our chosen technology, the database, and are blessed with merely mortal powers of learning, then we like standards. Vendors of RDBMSs generally don’t conform to standards by instinct, but by customer demand. Microsoft has made great strides to adopt the international SQL Standards, where possible, thanks to considerable lobbying by the community. The implementation of Window functions is a great example. There is still work to do, though. SQL Server, for example, has an unusable version of the Information Schema. One cast-iron rule of any RDBMS is that we must be able to query the metadata using the same language that we use to query the data, i.e. SQL, and we do this by running queries against the INFORMATION_SCHEMA views. Developers who’ve attempted to apply a standard query that works on MySQL, or some other database, but doesn’t produce the expected results on SQL Server are advised to shun the Standards-based approach in favor of the vendor-specific one, using the catalog views. The argument behind this is sound and well-documented, and of course we all use those catalog views, out of necessity. And yet, as database professionals, committed to supporting the best databases for the business, whatever they are now and in the future, surely our heart should sink somewhat when we advocate a vendor specific approach, to a developer struggling with something as simple as writing a guard clause. And when we read messages on the Microsoft documentation informing us that we shouldn’t rely on INFORMATION_SCHEMA to identify reliably the schema of an object, in SQL Server!

  Read the article

• The Growing Importance of Network Virtualization

  - by user12608550

  The Growing Importance of Network Virtualization We often focus on server virtualization when we discuss cloud computing, but just as often we neglect to consider some of the critical implications of that technology. The ability to create virtual environments (or VEs [1]) means that we can create, destroy, activate and deactivate, and more importantly, MOVE them around within the cloud infrastructure. This elasticity and mobility has profound implications for how network services are defined, managed, and used to provide cloud services. It's not just servers that benefit from virtualization, it's the network as well. Network virtualization is becoming a hot topic, and not just for discussion but for companies like Oracle and others who have recently acquired net virtualization companies [2,3]. But even before this topic became so prominent, Solaris engineers were working on technologies in Solaris 11 to virtualize network services, known as Project Crossbow [4]. And why is network virtualization so important? Because old assumptions about network devices, topology, and management must be re-examined in light of the self-service, elasticity, and resource sharing requirements of cloud computing infrastructures. Static, hierarchical network designs, and inter-system traffic flows, need to be reconsidered and quite likely re-architected to take advantage of new features like virtual NICs and switches, bandwidth control, load balancing, and traffic isolation. For example, traditional multi-tier Web services (Web server, App server, DB server) that share net traffic over Ethernet wires can now be virtualized and hosted on shared-resource systems that communicate within a larger server at system bus speeds, increasing performance and reducing wired network traffic. And virtualized traffic flows can be monitored and adjusted as needed to optimize network performance for dynamically changing cloud workloads. Additionally, as VEs come and go and move around in the cloud, static network configuration methods cannot easily accommodate the routing and addressing flexibility that VE mobility implies; virtualizing the network itself is a requirement. Oracle Solaris 11 [5] includes key network virtualization technologies needed to implement cloud computing infrastructures. It includes features for the creation and management of virtual NICs and switches, and for the allocation and control of the traffic flows among VEs [6]. Additionally it allows for both sharing and dedication of hardware components to network tasks, such as allocating specific CPUs and vNICs to VEs, and even protocol-specific management of traffic. So, have a look at your current network topology and management practices in view of evolving cloud computing technologies. And don't simply duplicate the physical architecture of servers and connections in a virtualized environment…rethink the traffic flows among VEs and how they can be optimized using Oracle Solaris 11 and other Oracle products and services. [1] I use the term "virtual environment" or VE here instead of the more commonly used "virtual machine" or VM, because not all virtualized operating system environments are full OS kernels under the control of a hypervisor…in other words, not all VEs are VMs. In particular, VEs include Oracle Solaris zones, as well as SPARC VMs (previously called LDoms), and x86-based Solaris and Linux VMs running under hypervisors such as OEL, Xen, KVM, or VMware. [2] Oracle follows VMware into network virtualization space with Xsigo purchase; http://www.mercurynews.com/business/ci_21191001/oracle-follows-vmware-into-network-virtualization-space-xsigo [3] Oracle Buys Xsigo; http://www.oracle.com/us/corporate/press/1721421 [4] Oracle Solaris 11 Networking Virtualization Technology, http://www.oracle.com/technetwork/server-storage/solaris11/technologies/networkvirtualization-312278.html [5] Oracle Solaris 11; http://www.oracle.com/us/products/servers-storage/solaris/solaris11/overview/index.html [6] For example, the Solaris 11 'dladm' command can be used to limit the bandwidth of a virtual NIC, as follows: dladm create-vnic -l net0 -p maxbw=100M vnic0

  Read the article

• At what point does "constructive" criticism of your code become unhelpful?

  - by user15859

  I recently started as a junior developer. As well as being one of the least experienced people on the team, I'm also a woman, which comes with all sorts of its own challenges working in a male-dominated environment. I've been having problems lately because I feel like I am getting too much unwarranted pedantic criticism on my work. Let me give you an example of what happened recently. Team lead was too busy to push in some branches I made, so he didn't get to them until the weekend. I checked my mail, not really meaning to do any work, and found that my two branches had been rejected on the basis of variable names, making error messages more descriptive, and moving some values to the config file. I don't feel that rejecting my branch on this basis is useful. Lots of people were working over the weekend, and I had never said that I would be working. Effectively, some people were probably blocked because I didn't have time to make the changes and resubmit. We are working on a project that is very time-sensitive, and it seems to me that it's not helpful to outright reject code based on things that are transparent to the client. I may be wrong, but it seems like these kinds of things should be handled in patch type commits when I have time. Now, I can see that in some environments, this would be the norm. However, the criticism doesn't seem equally distributed, which is what leads to my next problem. The basis of most of these problems was due to the fact that I was in a codebase that someone else had written and was trying to be minimally invasive. I was mimicking the variable names used elsewhere in the file. When I stated this, I was bluntly told, "Don't mimic others, just do what's right." This is perhaps the least useful thing I could have been told. If the code that is already checked in is unacceptable, how am I supposed to tell what is right and what is wrong? If the basis of the confusion was coming from the underlying code, I don't think it's my responsibility to spend hours refactoring a whole file that someone else wrote (and works perfectly well), potentially introducing new bugs etc. I'm feeling really singled out and frustrated in this situation. I've gotten a lot better about following the standards that are expected, and I feel frustrated that, for example, when I refactor a piece of code to ADD error checking that was previously missing, I'm only told that I didn't make the errors verbose enough (and the branch was rejected on this basis). What if I had never added it to begin with? How did it get into the code to begin with if it was so wrong? This is why I feel so singled out: I constantly run into this existing problematic code, that I either mimic or refactor. When I mimic it, it's "wrong", and if I refactor it, I'm chided for not doing enough (and if I go all the way, introducing bugs, etc). Again, if this is such a problem, I don't understand how any code gets into the codebase, and why it becomes my responsibility when it was written by someone else, who apparently didn't have their code reviewed. Anyway, how do I deal with this? Please remember that I said at the top that I'm a woman, and I'm sure these guys don't usually have to worry about decorum when they're reviewing other guys' code, but honestly that doesn't work for me, and it's causing me to be less productive. I'm worried that if I talk to my manager about it, he'll think I can't handled the environment, etc.

  Read the article

• Is this Hybrid of Interface / Composition kosher?

  - by paul

  I'm working on a project in which I'm considering using a hybrid of interfaces and composition as a single thing. What I mean by this is having a contain*ee* class be used as a front for functionality implemented in a contain*er* class, where the container exposes the containee as a public property. Example (pseudocode): class Visibility(lambda doShow, lambda doHide, lambda isVisible) public method Show() {...} public method Hide() {...} public property IsVisible public event Shown public event Hidden class SomeClassWithVisibility private member visibility = new Visibility(doShow, doHide, isVisible) public property Visibility with get() = visibility private method doShow() {...} private method doHide() {...} private method isVisible() {...} There are three reasons I'm considering this: The language in which I'm working (F#) has some annoyances w.r.t. implementing interfaces the way I need to (unless I'm missing something) and this will help avoid a lot of boilerplate code. The containee classes could really be considered properties of the container class(es); i.e. there seems to be a fairly strong has-a relationship. The containee classes will likely implement code which would have been pretty much the same when implemented in all the container classes, so why not do it once in one place? In the above example, this would include managing and emitting the Shown/Hidden events. Does anyone see any isseus with this Composiface/Intersition method, or know of a better way? EDIT 2012.07.26 - It seems a little background information is warranted: Where I work, we have a bunch of application front-ends that have limited access to system resources -- they need access to these resources to fully function. To remedy this we have a back-end application that can access the needed resources, with which the front-ends can communicate. (There is an API written for the front-ends for accessing back-end functionality as though it were part of the front-end.) The back-end program is out of date and its functionality is incomplete. It has made the transition from company to company a couple of times and we can't even compile it anymore. So I'm trying to rewrite it in my spare time. I'm trying to update things to make a nice(r) interface/API for the front-ends (while allowing for backwards compatibility with older front-ends), hopefully something full of OOPy goodness. The thing is, I don't want to write the front-end API after I've written pretty much the same code in F# for implementing the back-end; so, what I'm planning on doing is applying attributes to classes/methods/properties that I would like to have code for in the API then generate this code from the F# assembly using reflection. The method outlined in this question is a possible alternative I'm considering instead of implementing straight interfaces on the classes in F# because they're kind of a bear: In order to access something of an interface that has been implemented in a class, you have to explicitly cast an instance of that class to the interface type. This would make things painful when getting calls from the front-ends. If you don't want to have to do this, you have to call out all of the interface's methods/properties again in the class, outside of the interface implementation (which is separate from regular class members), and call the implementation's members. This is basically repeating the same code, which is what I'm trying to avoid!

  Read the article

• The five steps of business intelligence adoption: where are you?

  - by Red Gate Software BI Tools Team

  When I was in Orlando and New York last month, I spoke to a lot of business intelligence users. What they told me suggested a path of BI adoption. The user’s place on the path depends on the size and sophistication of their organisation. Step 1: A company with a database of customer transactions will often want to examine particular data, like revenue and unit sales over the last period for each product and territory. To do this, they probably use simple SQL queries or stored procedures to produce data on demand. Step 2: The results from step one are saved in an Excel document, so business users can analyse them with filters or pivot tables. Alternatively, SQL Server Reporting Services (SSRS) might be used to generate a report of the SQL query for display on an intranet page. Step 3: If these queries are run frequently, or business users want to explore data from multiple sources more freely, it may become necessary to create a new database structured for analysis rather than CRUD (create, retrieve, update, and delete). For example, data from more than one system — plus external information — may be incorporated into a data warehouse. This can become ‘one source of truth’ for the business’s operational activities. The warehouse will probably have a simple ‘star’ schema, with fact tables representing the measures to be analysed (e.g. unit sales, revenue) and dimension tables defining how this data is aggregated (e.g. by time, region or product). Reports can be generated from the warehouse with Excel, SSRS or other tools. Step 4: Not too long ago, Microsoft introduced an Excel plug-in, PowerPivot, which allows users to bring larger volumes of data into Excel documents and create links between multiple tables.  These BISM Tabular documents can be created by the database owners or other expert Excel users and viewed by anyone with Excel PowerPivot. Sometimes, business users may use PowerPivot to create reports directly from the primary database, bypassing the need for a data warehouse. This can introduce problems when there are misunderstandings of the database structure or no single ‘source of truth’ for key data. Step 5: Steps three or four are often enough to satisfy business intelligence needs, especially if users are sophisticated enough to work with the warehouse in Excel or SSRS. However, sometimes the relationships between data are too complex or the queries which aggregate across periods, regions etc are too slow. In these cases, it can be necessary to formalise how the data is analysed and pre-build some of the aggregations. To do this, a business intelligence professional will typically use SQL Server Analysis Services (SSAS) to create a multidimensional model — or “cube” — that more simply represents key measures and aggregates them across specified dimensions. Step five is where our tool, SSAS Compare, becomes useful, as it helps review and deploy changes from development to production. For us at Red Gate, the primary value of SSAS Compare is to establish a dialog with BI users, so we can develop a portfolio of products that support creation and deployment across a range of report and model types. For example, PowerPivot and the new BISM Tabular model create a potential customer base for tools that extend beyond BI professionals. We’re interested in learning where people are in this story, so we’ve created a six-question survey to find out. Whether you’re at step one or step five, we’d love to know how you use BI so we can decide how to build tools that solve your problems. So if you have a sixty seconds to spare, tell us on the survey!

  Read the article

• Html.ValidationSummary and Multiple Forms

  - by MightyZot

  Originally posted on: http://geekswithblogs.net/MightyZot/archive/2013/11/11/html.validationsummary-and-multiple-forms.aspxThe Html.ValidationSummary helper writes a div with a list of general errors added to the model state while a request is being serviced. There is generally one form per view or partial view, I think, so often there is only one call to Html.ValidationSummary in the page resulting from the assembly of your views. And, consequently, there is no problem with the markup that Html.ValidationSummary spits out as a result. What if you want to put multiple forms in one view? Even if you create a view model that’s an aggregate of the view models for each form, the error validation summary is going to contain errors from both forms. Check out this screen shot, which shows a page with multiple forms. Notice how the error validation summary shows up twice. Grrr! Errors for the login form also show up in the registration form. Luckily, there is an easy way around this. Pull the errors out of the model state and separate them for each form. You’ll need to identify the appropriate form by setting the key when you make calls to ModelState.AddModelError. Assume in my example that errors for the login form are added to model state using the “LoginForm” key. And, likewise, assume that errors for the registration form are added to model state using the “RegistrationForm” key. An example of that might look like this… // If we got this far, something failed, redisplay form ModelState.AddModelError("LoginForm", "User name or password is not right..."); return View(model); Over in the code for your View, you can pull each form’s errors from the model state using lambda expressions that look like these… var LoginFormErrors = ViewData.ModelState.Where(ms => ms.Key == "LoginForm"); var RegistrationFormErrors = ViewData.ModelState.Where(ms => ms.Key == "RegistrationForm"); Now that you have two collections containing errors, you can display only the errors specific to each form. I’m doing that in my code by removing the calls to Html.ValidationSummary and replacing them with enumerators that look like this… if(LoginFormErrors.Count() > 0) { <div class="cdt-error-list">     <ul>     @foreach (var entry in LoginFormErrors)     {         foreach (var error in entry.Value.Errors)         {             <li>@error.ErrorMessage</li>         }     }     </ul> </div> } …and for the registration form, the code looks like this… @if(RegistrationFormErrors.Count() > 0) { <div class="cdt-error-list">     <ul>     @foreach (var entry in RegistrationFormErrors)     {         foreach (var error in entry.Value.Errors)         {             <li>@error.ErrorMessage</li>         }     }     </ul> </div> } The result is a nice clean separation of the list of errors that are specific to each form. And, this is important because each form is submitted separately in my case, so both forms don’t generate errors in the same context. As you’ll see in the screen shot below, errors added to the model state when the login form is submitted do not show up in the registration form’s validation summary.

  Read the article

• Juggling with JDKs on Apple OS X

  - by Blueberry Coder

  I recently got a shiny new MacBook Pro to help me support our ADF Mobile customers. It is really a wonderful piece of hardware, although I am still adjusting to Apple's peculiar keyboard layout. Did you know, for example, that the « delete » key actually performs a « backspace »? But I disgress... As you may know, ADF Mobile development still requires JDeveloper 11gR2, which in turn runs on Java 6. On the other hand, JDeveloper 12c needs JDK 7. I wanted to install both versions, and wasn't sure how to do it.   If you remember, I explained in a previous blog entry how to install JDeveloper 11gR2 on Apple's OS X. The trick was to use the /usr/libexec/java_home command in order to invoke the proper JDK. In this case, I could have done the same thing; the two JDKs can coexist without any problems, since they install in completely different locations. But I wanted more than just installing JDeveloper. I wanted to be able to select my JDK when using the command line as well. On Windows, this is easy, since I keep all my JDKs in a central location. I simply have to move to the appropriate folder or type the folder name in the command I want to execute. Problem is, on OS X, the paths to the JDKs are... let's say convoluted.  Here is the one for Java 6. /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home The Java 7 path is not better, just different. /Library/Java/JavaVirtualMachines/jdk1.7.0_45.jdk/Contents/Home Intuitive, isn't it? Clearly, I needed something better... On OS X, the default command shell is bash. It is possible to configure the shell environment by creating a file named « .profile » in a user's home folder. Thus, I created such a file and put the following inside: export JAVA_7_HOME=$(/usr/libexec/java_home -v1.7) export JAVA_6_HOME=$(/usr/libexec/java_home -v1.6) export JAVA_HOME=$JAVA_7_HOME alias java6='export JAVA_HOME=$JAVA_6_HOME' alias java7='export JAVA_HOME=$JAVA_7_HOME'  The first two lines retrieve the current paths for Java 7 and Java 6 and store them in two environment variables. The third line marks Java 7 as the default. The last two lines create command aliases. Thus, when I type java6, the value for JAVA_HOME is set to JAVA_6_HOME, for example.  I now have an environment which works even better than the one I have on Windows, since I can change my active JDK on a whim. Here a sample, fresh from my terminal window. fdesbien-mac:~ fdesbien$ java6 fdesbien-mac:~ fdesbien$ java -version java version "1.6.0_65" Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609) Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode) fdesbien-mac:~ fdesbien$ fdesbien-mac:~ fdesbien$ java7 fdesbien-mac:~ fdesbien$ java -version java version "1.7.0_45" Java(TM) SE Runtime Environment (build 1.7.0_45-b18) Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode) fdesbien-mac:~ fdesbien$ Et voilà! Maximum flexibility without downsides, just I like it. 

  Read the article

• Bounding Box Collision Glitching Problem (Pygame)

  - by Ericson Willians

  So far the "Bounding Box" method is the only one that I know. It's efficient enough to deal with simple games. Nevertheless, the game I'm developing is not that simple anymore and for that reason, I've made a simplified example of the problem. (It's worth noticing that I don't have rotating sprites on my game or anything like that. After showing the code, I'll explain better). Here's the whole code: from pygame import * DONE = False screen = display.set_mode((1024,768)) class Thing(): def __init__(self,x,y,w,h,s,c): self.x = x self.y = y self.w = w self.h = h self.s = s self.sur = Surface((64,48)) draw.rect(self.sur,c,(self.x,self.y,w,h),1) self.sur.fill(c) def draw(self): screen.blit(self.sur,(self.x,self.y)) def move(self,x): if key.get_pressed()[K_w] or key.get_pressed()[K_UP]: if x == 1: self.y -= self.s else: self.y += self.s if key.get_pressed()[K_s] or key.get_pressed()[K_DOWN]: if x == 1: self.y += self.s else: self.y -= self.s if key.get_pressed()[K_a] or key.get_pressed()[K_LEFT]: if x == 1: self.x -= self.s else: self.x += self.s if key.get_pressed()[K_d] or key.get_pressed()[K_RIGHT]: if x == 1: self.x += self.s else: self.x -= self.s def warp(self): if self.y < -48: self.y = 768 if self.y > 768 + 48: self.y = 0 if self.x < -64: self.x = 1024 + 64 if self.x > 1024 + 64: self.x = -64 r1 = Thing(0,0,64,48,1,(0,255,0)) r2 = Thing(6*64,6*48,64,48,1,(255,0,0)) while not DONE: screen.fill((0,0,0)) r2.draw() r1.draw() # If not intersecting, then moves, else, it moves in the opposite direction. if not ((((r1.x + r1.w) > (r2.x - r1.s)) and (r1.x < ((r2.x + r2.w) + r1.s))) and (((r1.y + r1.h) > (r2.y - r1.s)) and (r1.y < ((r2.y + r2.h) + r1.s)))): r1.move(1) else: r1.move(0) r1.warp() if key.get_pressed()[K_ESCAPE]: DONE = True for ev in event.get(): if ev.type == QUIT: DONE = True display.update() quit() The problem: In my actual game, the grid is fixed and each tile has 64 by 48 pixels. I know how to deal with collision perfectly if I moved by that size. Nevertheless, obviously, the player moves really fast. In the example, the collision is detected pretty well (Just as I see in many examples throughout the internet). The problem is that if I put the player to move WHEN IS NOT intersecting, then, when it touches the obstacle, it does not move anymore. Giving that problem, I began switching the directions, but then, when it touches and I press the opposite key, it "glitches through". My actual game has many walls, and the player will touch them many times, and I can't afford letting the player go through them. The code-problem illustrated: When the player goes towards the wall (Fine). When the player goes towards the wall and press the opposite direction. (It glitches through). Here is the logic I've designed before implementing it: I don't know any other method, and I really just want to have walls fixed in a grid, but move by 1 or 2 or 3 pixels (Slowly) and have perfect collision without glitching-possibilities. What do you suggest?

  Read the article

• Patterns for a tree of persistent data with multiple storage options?

  - by Robin Winslow

  I have a real-world problem which I'll try to abstract into an illustrative example. So imagine I have data objects in a tree, where parent objects can access children, and children can access parents: // Interfaces interface IParent<TChild> { List<TChild> Children; } interface IChild<TParent> { TParent Parent; } // Classes class Top : IParent<Middle> {} class Middle : IParent<Bottom>, IChild<Top> {} class Bottom : IChild<Middle> {} // Usage var top = new Top(); var middles = top.Children; // List<Middle> foreach (var middle in middles) { var bottoms = middle.Children; // List<Bottom> foreach (var bottom in bottoms) { var middle = bottom.Parent; // Access the parent var top = middle.Parent; // Access the grandparent } } All three data objects have properties that are persisted in two data stores (e.g. a database and a web service), and they need to reflect and synchronise with the stores. Some objects only request from the web service, some only write to it. Data Mapper My favourite pattern for data access is Data Mapper, because it completely separates the data objects themselves from the communication with the data store: class TopMapper { public Top FetchById(int id) { var top = new Top(DataStore.TopDataById(id)); top.Children = MiddleMapper.FetchForTop(Top); return Top; } } class MiddleMapper { public Middle FetchById(int id) { var middle = new Middle(DataStore.MiddleDataById(id)); middle.Parent = TopMapper.FetchForMiddle(middle); middle.Children = BottomMapper.FetchForMiddle(bottom); return middle; } } This way I can have one mapper per data store, and build the object from the mapper I want, and then save it back using the mapper I want. There is a circular reference here, but I guess that's not a problem because most languages can just store memory references to the objects, so there won't actually be infinite data. The problem with this is that every time I want to construct a new Top, Middle or Bottom, it needs to build the entire object tree within that object's Parent or Children property, with all the data store requests and memory usage that that entails. And in real life my tree is much bigger than the one represented here, so that's a problem. Requests in the object In this the objects request their Parents and Children themselves: class Middle { private List<Bottom> _children = null; // cache public List<Bottom> Children { get { _children = _children ?? BottomMapper.FetchForMiddle(this); return _children; } set { BottomMapper.UpdateForMiddle(this, value); _children = value; } } } I think this is an example of the repository pattern. Is that correct? This solution seems neat - the data only gets requested from the data store when you need it, and thereafter it's stored in the object if you want to request it again, avoiding a further request. However, I have two different data sources. There's a database, but there's also a web service, and I need to be able to create an object from the web service and save it back to the database and then request it again from the database and update the web service. This also makes me uneasy because the data objects themselves are no longer ignorant of the data source. We've introduced a new dependency, not to mention a circular dependency, making it harder to test. And the objects now mask their communication with the database. Other solutions Are there any other solutions which could take care of the multiple stores problem but also mean that I don't need to build / request all the data every time?

  Read the article

< Previous Page | 321 322 323 324 325 326 327 328 329 330 331 332  | Next Page >