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  • Leveraging Social Networks for Retail

    - by David Dorf
    For retailers, social media is all about B2C2C. That is, Business to Consumer to Consumer, or more specifically, retailer to influencer to consumer. Traditional marketing targeted mass media, trying to expose the message to as many people as possible. While effective, this approach has never been very efficient, with high costs for relatively low penetration. Then it was thought that marketers should focus their efforts on a relative few super-influencers that would then sway the masses. History shows a few successes with this approach but lacked any consistency or predictability. After all, if super-influencers were easy to find, most campaigns would easily go viral. Alas, research shows that most wide-spread trends were the result of several fortunate events, including some luck. So do people exert influence over each other when it comes to purchase decisions? Of course they do, all the time. But that influence is usually limited to a small set of friends and specific specialization. For instance, although I have 165 friends on Facebook, I am only able to influence my close friends and family on PC purchases, and I have no sway at all for fashion purchases. People trust my knowledge on technology, but nobody asks my advice on shoes. How then should retailers leverage social networks in order to reinforce brand image and push promotions? Two obvious ways are Like and Share. Online advertisements or wall-postings receive more clicks when the viewer sees that friends have "liked" the posting. That's our modern-day version of word-of-mouth advertising. Statistics show that endorsements from friends make it more likely a person will engage. If my friends and I liked it, then I might also "share" (or "retweet" in the case of Twitter) it with other friends. In that case the retailer has paid for X showings of the advertisement, but sharing has pushed it to an additional Y people at no cost. And further, the implicit endorsement by the sharer makes it more likely the recipient will engage. So a good first step is to find people active in social networks that will Like and Share in order to exert influence. Its still tough to go viral, but doubling engagement is still a big step in the right direction. More complex social graph analysis would be a second step, but I'll leave that topic for another day. If you're interested in the academic side of social dynamics, I suggest reading Duncan Watts' work.

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  • Understanding Data Science: Recent Studies

    - by Joe Lamantia
    If you need such a deeper understanding of data science than Drew Conway's popular venn diagram model, or Josh Wills' tongue in cheek characterization, "Data Scientist (n.): Person who is better at statistics than any software engineer and better at software engineering than any statistician." two relatively recent studies are worth reading.   'Analyzing the Analyzers,' an O'Reilly e-book by Harlan Harris, Sean Patrick Murphy, and Marck Vaisman, suggests four distinct types of data scientists -- effectively personas, in a design sense -- based on analysis of self-identified skills among practitioners.  The scenario format dramatizes the different personas, making what could be a dry statistical readout of survey data more engaging.  The survey-only nature of the data,  the restriction of scope to just skills, and the suggested models of skill-profiles makes this feel like the sort of exercise that data scientists undertake as an every day task; collecting data, analyzing it using a mix of statistical techniques, and sharing the model that emerges from the data mining exercise.  That's not an indictment, simply an observation about the consistent feel of the effort as a product of data scientists, about data science.  And the paper 'Enterprise Data Analysis and Visualization: An Interview Study' by researchers Sean Kandel, Andreas Paepcke, Joseph Hellerstein, and Jeffery Heer considers data science within the larger context of industrial data analysis, examining analytical workflows, skills, and the challenges common to enterprise analysis efforts, and identifying three archetypes of data scientist.  As an interview-based study, the data the researchers collected is richer, and there's correspondingly greater depth in the synthesis.  The scope of the study included a broader set of roles than data scientist (enterprise analysts) and involved questions of workflow and organizational context for analytical efforts in general.  I'd suggest this is useful as a primer on analytical work and workers in enterprise settings for those who need a baseline understanding; it also offers some genuinely interesting nuggets for those already familiar with discovery work. We've undertaken a considerable amount of research into discovery, analytical work/ers, and data science over the past three years -- part of our programmatic approach to laying a foundation for product strategy and highlighting innovation opportunities -- and both studies complement and confirm much of the direct research into data science that we conducted. There were a few important differences in our findings, which I'll share and discuss in upcoming posts.

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  • Version control and data provenance in charts, slides, and marketing materials that derive from code ouput

    - by EMS
    I develop as part of a small team that mostly does research and statistics stuff. But from the output of our code, other teams often create promotional materials, slides, presentations, etc. We run into a big problem because the marketing team (non-programmers) tend to use Excel, Adobe products, or other tools to carry out their work, and just want easy-to-use data formats from us. This leads to data provenance problems. We see email chains with attachments from 6 months ago and someone is saying "Hey, who generated this data. Can you generate more of it with the recent 6 months of results added in?" I want to help the other teams effectively use version control (my team uses it reasonably well for the code, but every other team classically comes up with many excuses to avoid it). For version controlling a software project where the participants are coders, I have some reasonable understanding of best practices and what to do. But for getting a team of marketing professionals to version control marketing materials and associate metadata about the software used to generate the data for the charts, I'm a bit at a loss. Some of the goals I'd like to achieve: Data that supported a material should never be associated with a person. As in, it should never be the case that someone says "Hey Person XYZ, I see you sent me this data as an attachment 6 months ago, can you update it for me?" Rather, data should be associated with the code and code-version of any code that was used to get it, and perhaps a team of many people who may maintain that code. Then references for data updates are about executing a specific piece of code, with a known version number. I'd like this to be a process that works easily with the tech that the marketing team already uses (e.g. Excel files, Adobe file, whatever). I don't want to burden them with needing to learn a bunch of new stuff just to use version control. They are capable folks, so learning something is fine. Ideally they could use our existing version control framework, but there are some issues around that. I think knowing some general best practices will be enough though, and I can handle patching that into the way our stuff works now. Are there any goals I am failing to think about? What are the time-tested ways to do something like this?

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  • links for 2011-01-04

    - by Bob Rhubart
    Webcasts (tags: ping.fm) Five Key Trends in Enterprise 2.0 for 2011 (Oracle Enterprise 2.0 Blog) Kellsey Ruppel shares insight from Oracle's Andy MacMillan. (tags: oracle otn enterprise2.0) Victor Bax: Lost in Service Oriented Architecture? "SOA is a concept, no more, no less. SOA is not a technology, or a piece of software. It is an architecture, a model." - Victor Bax (tags: oracle soa) Jan-Leendert: Oracle 11g SOA Suite read multi record data from csv file with the file adapter (master-detail) "The file adapter is a very powerlful tool to read files with structured data. Most of the time you will read simple csv files with one record per row. But what if your csv file contains multiple records with different types?" - Jan-Leendert (tags: oracle soa soasuite) @myfear: Five ways to know how your data looked in the past. Entity Auditing. "Whatever requirements you have. I can promise you, that it will never be a simple solution. In general it's best to evaluate your purpose for auditing in detail." - Oracle ACE Director Markus Eisele (tags: oracle otn oracleace java) @fteter: Buffing Up The Crystal Ball "While I'm already tired of seeing these types of posts (I'm writing on New Year's Day), I'm also feeling guilty about not making my own set of predictions." - Oracle ACE Director Floyd Teter (tags: oracle otn oracleace ec2 cloud fusionmiddleware) @bex: ECM New Year's Resolutions "Happy new year! Most people use the first post of the year to go over their own blog statistics of popular posts... but since my blog's fiscal year ends in April, I decided to do new years resolutions instead." - Oracle ACE Director Bex Huff (tags: oracle otn oracleace ecm enterprise2.0) Izaak de Hullu: Embedded Java in a 11g BPEL process "In an earlier blog my colleague Peter Ebell explained how you can create an extension of com.collaxa.cube.engine.ext.BPELXExecLet to do your coding in a regular Java environment so you have code completion and validation..." - Izaak de Hullu (tags: oracle otn bpel java soa) @gschmutz: Cannot access EM console after installing SOA Suite 11g PS2 Oracle ACE Director Guido Schmutz encounters a problem and shares the solution. (tags: oracle otn oracleace soa soasuite)

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  • JSP Precompilation for ADF Applications

    - by Duncan Mills
    A question that comes up from time to time, particularly in relation to build automation, is how to best pre-compile the .jspx and .jsff files in an ADF application. Thus ensuring that the app is ready to run as soon as it's installed into WebLogic. In the normal run of things, the first poor soul to hit a page pays the price and has to wait a little whilst the JSP is compiled into a servlet. Everyone else subsequently gets a free lunch. So it's a reasonable thing to want to do... Let Me List the Ways So forth to Google (other search engines are available)... which lead me to a fairly old article on WLDJ - Removing Performance Bottlenecks Through JSP Precompilation. Technololgy wise, it's somewhat out of date, but the one good point that it made is that it's really not very useful to try and use the precompile option in the weblogic.xml file. That's a really good observation - particularly if you're trying to integrate a pre-compile step into a Hudson Continuous Integration process. That same article mentioned an alternative approach for programmatic pre-compilation using weblogic.jspc. This seemed like a much more useful approach for a CI environment. However, weblogic.jspc is now obsoleted by weblogic.appc so we'll use that instead.  Thanks to Steve for the pointer there. And So To APPC APPC has documentation - always a great place to start, and supports usage both from Ant via the wlappc task and from the command line using the weblogic.appc command. In my testing I took the latter approach. Usage, as the documentation will show you, is superficially pretty simple.  The nice thing here, is that you can pass an existing EAR file (generated of course using OJDeploy) and that EAR will be updated in place with the freshly compiled servlet classes created from the JSPs. Appc takes care of all the unpacking, compiling and re-packing of the EAR for you. Neat.  So we're done right...? Not quite. The Devil is in the Detail  OK so I'm being overly dramatic but it's not all plain sailing, so here's a short guide to using weblogic.appc to compile a simple ADF application without pain.  Information You'll Need The following is based on the assumption that you have a stand-alone WLS install with the Application Development  Runtime installed and a suitable ADF enabled domain created. This could of course all be run off of a JDeveloper install as well 1. Your Weblogic home directory. Everything you need is relative to this so make a note.  In my case it's c:\builds\wls_ps4. 2. Next deploy your EAR as normal and have a peek inside it using your favourite zip management tool. First of all look at the weblogic-application.xml inside the EAR /META-INF directory. Have a look for any library references. Something like this: <library-ref>    <library-name>adf.oracle.domain</library-name> </library-ref>   Make a note of the library ref (adf.oracle.domain in this case) , you'll need that in a second. 3. Next open the nested WAR file within the EAR and then have a peek inside the weblogic.xml file in the /WEB-INF directory. Again  make a note of the library references. 4. Now start the WebLogic as per normal and run the WebLogic console app (e.g. http://localhost:7001/console). In the Domain Structure navigator, select Deployments. 5. For each of the libraries you noted down drill into the library definition and make a note of the .war, .ear or .jar that defines the library. For example, in my case adf.oracle.domain maps to "C:\ builds\ WLS_PS4\ oracle_common\ modules\ oracle. adf. model_11. 1. 1\ adf. oracle. domain. ear". Note the extra spaces that are salted throughout this string as it is displayed in the console - just to make it annoying, you'll have to strip these out. 6. Finally you'll need the location of the adfsharebean.jar. We need to pass this on the classpath for APPC so that the ADFConfigLifeCycleCallBack listener can be found. In a more complex app of your own you may need additional classpath entries as well.  Now we're ready to go, and it's a simple matter of applying the information we have gathered into the relevant command line arguments for the utility A Simple CMD File to Run APPC  Here's the stub .cmd file I'm using on Windows to run this. @echo offREM Stub weblogic.appc Runner setlocal set WLS_HOME=C:\builds\WLS_PS4 set ADF_LIB_ROOT=%WLS_HOME%\oracle_common\modulesset COMMON_LIB_ROOT=%WLS_HOME%\wlserver_10.3\common\deployable-libraries set ADF_WEBAPP=%ADF_LIB_ROOT%\oracle.adf.view_11.1.1\adf.oracle.domain.webapp.war set ADF_DOMAIN=%ADF_LIB_ROOT%\oracle.adf.model_11.1.1\adf.oracle.domain.ear set JSTL=%COMMON_LIB_ROOT%\jstl-1.2.war set JSF=%COMMON_LIB_ROOT%\jsf-1.2.war set ADF_SHARE=%ADF_LIB_ROOT%\oracle.adf.share_11.1.1\adfsharembean.jar REM Set up the WebLogic Environment so appc can be found call %WLS_HOME%\wlserver_10.3\server\bin\setWLSEnv.cmd CLS REM Now compile away!java weblogic.appc -verbose -library %ADF_WEBAPP%,%ADF_DOMAIN%,%JSTL%,%JSF% -classpath %ADF_SHARE% %1 endlocal Running the above on a target ADF .ear  file will zip through and create all of the relevant compiled classes inside your nested .war file in the \WEB-INF\classes\jsp_servlet\ directory (but don't take my word for it, run it and take a look!) And So... In the immortal words of  the Pet Shop Boys, Was It Worth It? Well, here's where you'll have to do your own testing. In  my case here, with a simple ADF application, pre-compilation shaved an non-scientific "3 Elephants" off of the initial page load time for the first access of each page. That's a pretty significant payback for such a simple step to add into your CI process, so why not give it a go.

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  • SQL SERVER – Template Browser – A Very Important and Useful Feature of SSMS

    - by pinaldave
    Let me start today’s blog post with a direction question. How many of you have ever used Template Browser? Template Browser is a very important and useful feature of SQL Server Management Studio (SSMS). Every time when I am talking about SQL Server there is always someone comes up with the question, why there is no step by step procedure included in SSMS for features. Honestly every time I get this question, the question I ask back is How many of you have ever used Template Browser? I think the answer to this question is most of the time either no or we have not heard of the feature. One of the people asked me back – have you ever written about it on your blog? I have not yet written about it. Basically there is nothing much to write about it. It is pretty straight forward feature, like any other feature and it is indeed difficult to elaborate. However, I will try to give a quick introduction to this feature. Templates are like a quick cheat sheet or quick reference. Templates are available to create objects like databases, tables, views, indexes, stored procedures, triggers, statistics, and functions. Templates are also available for Analysis Services as well. The template scripts contain parameters to help you customize the code. You can Replace Template Parameters dialog box to insert values into the script. Additionally users can create new custom templates as well with folder structure. To open a template from Template Explorer Go to View menu >> Template Explorer or type CTRL+ALT+L. You will find a list of categories click on any category and expand the folder structure. For our sample example let us expand Index Folder. In this folder you will notice the various T-SQL Scripts. These scripts can be opened by double click or can be dragged to editor area and modified as needed. Sample template is now available in the query editor area with all the necessary parameter place folder. You can replace the same parameter by typing either CTRL+SHIFT+M or by going to Query Menu >> Specify Values for Template Parameters. In this screen it will show  Specify Values for Template Parameters dialog box, accept the value or replace it with a new value. This will now get your script ready to go. Check it one more time and change the script to fit your requirement. I personally use template explorer for two things. First one is obviously for templates but the hidden one and an important one is for learning new features and T-SQL commands. There is so much to learn and so little time. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology

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  • Real tortoises keep it slow and steady. How about the backups?

    - by Maria Zakourdaev
      … Four tortoises were playing in the backyard when they decided they needed hibiscus flower snacks. They pooled their money and sent the smallest tortoise out to fetch the snacks. Two days passed and there was no sign of the tortoise. "You know, she is taking a lot of time", said one of the tortoises. A little voice from just out side the fence said, "If you are going to talk that way about me I won't go." Is it too much to request from the quite expensive 3rd party backup tool to be a way faster than the SQL server native backup? Or at least save a respectable amount of storage by producing a really smaller backup files?  By saying “really smaller”, I mean at least getting a file in half size. After Googling the internet in an attempt to understand what other “sql people” are using for database backups, I see that most people are using one of three tools which are the main players in SQL backup area:  LiteSpeed by Quest SQL Backup by Red Gate SQL Safe by Idera The feedbacks about those tools are truly emotional and happy. However, while reading the forums and blogs I have wondered, is it possible that many are accustomed to using the above tools since SQL 2000 and 2005.  This can easily be understood due to the fact that a 300GB database backup for instance, using regular a SQL 2005 backup statement would have run for about 3 hours and have produced ~150GB file (depending on the content, of course).  Then you take a 3rd party tool which performs the same backup in 30 minutes resulting in a 30GB file leaving you speechless, you run to management persuading them to buy it due to the fact that it is definitely worth the price. In addition to the increased speed and disk space savings you would also get backup file encryption and virtual restore -  features that are still missing from the SQL server. But in case you, as well as me, don’t need these additional features and only want a tool that performs a full backup MUCH faster AND produces a far smaller backup file (like the gain you observed back in SQL 2005 days) you will be quite disappointed. SQL Server backup compression feature has totally changed the market picture. Medium size database. Take a look at the table below, check out how my SQL server 2008 R2 compares to other tools when backing up a 300GB database. It appears that when talking about the backup speed, SQL 2008 R2 compresses and performs backup in similar overall times as all three other tools. 3rd party tools maximum compression level takes twice longer. Backup file gain is not that impressive, except the highest compression levels but the price that you pay is very high cpu load and much longer time. Only SQL Safe by Idera was quite fast with it’s maximum compression level but most of the run time have used 95% cpu on the server. Note that I have used two types of destination storage, SATA 11 disks and FC 53 disks and, obviously, on faster storage have got my backup ready in half time. Looking at the above results, should we spend money, bother with another layer of complexity and software middle-man for the medium sized databases? I’m definitely not going to do so.  Very large database As a next phase of this benchmark, I have moved to a 6 terabyte database which was actually my main backup target. Note, how multiple files usage enables the SQL Server backup operation to use parallel I/O and remarkably increases it’s speed, especially when the backup device is heavily striped. SQL Server supports a maximum of 64 backup devices for a single backup operation but the most speed is gained when using one file per CPU, in the case above 8 files for a 2 Quad CPU server. The impact of additional files is minimal.  However, SQLsafe doesn’t show any speed improvement between 4 files and 8 files. Of course, with such huge databases every half percent of the compression transforms into the noticeable numbers. Saving almost 470GB of space may turn the backup tool into quite valuable purchase. Still, the backup speed and high CPU are the variables that should be taken into the consideration. As for us, the backup speed is more critical than the storage and we cannot allow a production server to sustain 95% cpu for such a long time. Bottomline, 3rd party backup tool developers, we are waiting for some breakthrough release. There are a few unanswered questions, like the restore speed comparison between different tools and the impact of multiple backup files on restore operation. Stay tuned for the next benchmarks.    Benchmark server: SQL Server 2008 R2 sp1 2 Quad CPU Database location: NetApp FC 15K Aggregate 53 discs Backup statements: No matter how good that UI is, we need to run the backup tasks from inside of SQL Server Agent to make sure they are covered by our monitoring systems. I have used extended stored procedures (command line execution also is an option, I haven’t noticed any impact on the backup performance). SQL backup LiteSpeed SQL Backup SQL safe backup database <DBNAME> to disk= '\\<networkpath>\par1.bak' , disk= '\\<networkpath>\par2.bak', disk= '\\<networkpath>\par3.bak' with format, compression EXECUTE master.dbo.xp_backup_database @database = N'<DBName>', @backupname= N'<DBName> full backup', @desc = N'Test', @compressionlevel=8, @filename= N'\\<networkpath>\par1.bak', @filename= N'\\<networkpath>\par2.bak', @filename= N'\\<networkpath>\par3.bak', @init = 1 EXECUTE master.dbo.sqlbackup '-SQL "BACKUP DATABASE <DBNAME> TO DISK= ''\\<networkpath>\par1.sqb'', DISK= ''\\<networkpath>\par2.sqb'', DISK= ''\\<networkpath>\par3.sqb'' WITH DISKRETRYINTERVAL = 30, DISKRETRYCOUNT = 10, COMPRESSION = 4, INIT"' EXECUTE master.dbo.xp_ss_backup @database = 'UCMSDB', @filename = '\\<networkpath>\par1.bak', @backuptype = 'Full', @compressionlevel = 4, @backupfile = '\\<networkpath>\par2.bak', @backupfile = '\\<networkpath>\par3.bak' If you still insist on using 3rd party tools for the backups in your production environment with maximum compression level, you will definitely need to consider limiting cpu usage which will increase the backup operation time even more: RedGate : use THREADPRIORITY option ( values 0 – 6 ) LiteSpeed : use  @throttle ( percentage, like 70%) SQL safe :  the only thing I have found was @Threads option.   Yours, Maria

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  • What can I do to make sure my code gets maintained in a developer light environment?

    - by asjohnson
    I am a contract data analyst, so I bounce between jobs every 3-6 months, which I find to be a good fit for me, but it leads to some problems when it comes to coding. I mostly do statistics (I've asked a similar question on cross validated, but the answers there are not relevant here), but I have also found out that the business world loves excel and loves copying and pasting the same thing over and over again even more. This led me to learn how to write VBA scripts and then VB.NET programs to automate as many of these reports as I can. I am certain my programs are not the most elegant, but I put a good bit of effort into making sure they work under as many cases as I can test, I add in exceptions and try to code so the program can handle changes in the files that it processes, but there is a limit, if you remove a huge portion of the data, there is a good chance my program is going to trip up, which I accept will inevitably happen. Usually a pretty minor change in the code fixes the problem and I do try and comment my code and make it readable under the assumption that some other person will have to read it some day. My problem is that I generally get put on teams of folks with essentially no experience with programming (like VBA would be a huge stretch for anyone I work directly with). I am wondering what I should be doing as the person that wrote the code to do my best to keep it maintained. I have two approaches in mind (outlined next), but would be very happy to get any advice. Solution 1: Find the more tech savvy coworkers and run them through the programs and what basic changes can be made. Honestly automating excel is about as easy as it can get when it comes to programming, so I feel like I could teach someone the basics of maintaining it pretty quick. Solution 2: Get in touch with the IT department and show them what is going on and maybe they will be able to help. The problem here is that the IT department is constantly swamped (as I'm sure many of you know) and I feel like kind of a jerk for dumping more things on them. I do leave my personal email address with places and am willing to answer quick questions via email, but I view the need for more exhaustive maintenance as something of an inevitability and would like to make sure I do my due diligence to make sure it gets done. I imagine some combination of the two approaches outlined there, but is there any kind of heads up I should give IT? I feel like I would be annoyed if I started getting requests to fix a program that I had never seen from some random guy that is no longer there.

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  • Why is my laptop so sluggish? Or Damn You Facebook and Twitter! Or All Hail Chrome!

    - by John Conwell
    In the past three weeks, I've noticed that my laptop (dual core 2.1GHz, 2Gb RAM) has become amazingly sluggish.  I only uses for communications and data lookup workflows, so the slowness was tolerable.  But today I finally got fed up with the suckyness and decided to get to the root of the problem (I do have strong performance roots after all). It actually didn't take all that long to figure it out.  About a year ago I converted to Google Chrome (away from FireFox).  One of the great tools Chrome has is a "Task Manager" tool, that gives you Windows Task Manager like details for all the tabs open in the browser (Shift + Esc).  Since every tab runs in its own process, its easy from Task Manager (both Windows or Chrome) to identify and kill a single performance offending tab.  This is unlike IE, where you only get aggregate data about all tabs open.  Anyway, I digress.  Today my laptop sucked.  Windows Task Manager told me that I had two memory hogging Chrome tabs, but couldn't tell me which web page those tabs are showing.  Enter Chrome Task Manager which tells you the page title, along with CPU, memory and network utilization of each tab.  Enter my amazement.  Turns out Facebook was using just shy of half a Gb of RAM.  Half a Gigabyte!  That's 512 Megabytes!524,288 Kilobytes! 536,870,912 Bytes!  Or 4,294,967,296 Bits!  In other words, that's a frackin boat load of memory.  Now consider that Facebook is running on pretty much 96.3% (statistics based on absolutely nothing) of every house hold desktop, laptop, netbook, and mobile device in America, that is pretty horrific! And I wasn't playing any Facebook games like FarmWars or MafiaVille.  I just had my normal, default home page up showing me who just had breakfast, or just got finished with their morning run. I'm sorry...let me say that again...HALF A GIG OF RAM!  That is just unforgivable. I can just see my mom calling me up:  Mom: "John...I think I need a new computer.  Mine is really slow these days" John: "What do you have running?" Mom: "Oh, just Facebook" John: "Ok, close Facebook and tell me how fast your computer feels" Mom: "Well...I don't know how fast it is.  All I do is use Facebook" John: "Ok Mom, I'll send you a new computer by Tuesday" Oh yea...and the other offending web page?  It was Twitter, using a quarter of a Gigabyte. God I love social networks!

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  • ANTS Memory Profiler 7.0

    - by Sam Abraham
    In the next few lines, I would like to briefly review ANTS Memory Profiler 7.0.  I was honored to be extended the opportunity to review this valuable tool as part of the GeeksWithBlogs influencers Program, a quarterly award providing its recipients access to valuable tools and enabling them with an opportunity to provide a brief write-up reviewing the complimentary tools they receive.   Typical Usage   ANTS Memory Profiler 7.0 is very intuitive and easy to use for any user be it novice or expert. A simple yet comprehensive menu screen enables the selection of the appropriate program type to profile as well as the executable or site for this program.   A typical use case starts with establishing a baseline memory snapshot, which tells us the initial memory cost used by the program under normal or low activity conditions. We would then take a second snapshot after the program has performed an activity which we want to investigate for memory leaks. We can then compare the initial baseline snapshot against the snapshot when the program has completed processing the activity in question to study anomalies in memory that did not get freed-up after the program has completed its performed function. The following are some screenshots outlining the selection of the program to profile (an executable for this demonstration’s purposes).   Figure 1 - Getting Started   Figure 2 - Selecting an Application to Profile     Features and Options   Right after the second snapshot is generated, Memory Profiler gives us immediate access to information on memory fragmentation, size differences between snapshots, unmanaged memory allocation and statistics on the largest classes taking up un-freed memory space.   We would also have the option to itemize objects held in memory grouped by object types within which we can study the instances allocated of each type. Filtering options enable us to quickly narrow object instances we are interested in.   Figure 3 - Easily accessible Execution Memory Information   Figure 4 - Class List   Figure 5 - Instance List   Figure 6-  Retention Graph for a Particular Instance   Conclusion I greatly enjoyed the opportunity to evaluate ANTS Memory Profiler 7.0. The tool's intuitive User Interface design and easily accessible menu options enabled me to quickly identify problem areas where memory was left unfreed in my code.     Tutorials and References  FInd out more About ANTS Memory Profiler 7.0 http://www.red-gate.com/supportcenter/Product?p=ANTS Memory Profiler   Checkout what other reviewers of this valuable tool have already shared: http://geekswithblogs.net/BlackRabbitCoder/archive/2011/03/10/ants-memory-profiler-7.0.aspx http://geekswithblogs.net/mikebmcl/archive/2011/02/28/ants-memory-profiler-7.0-review.aspx

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  • MS in Computer Science after BE in electronics

    - by Abhinav
    I am doing my 3rd year Bachelors in Electronics and Electrical Communication but from the first year I have been interested in Computer Science. But at that time it was just my hobby. But in second year when I joined robotics my love for computer science rose. I with my team came in top three in 2 National Competition (Technical fests of different IITs) where we used Image Processing, Hardware interfacing etc. But then I realised that Computer Science is not just about coding. I took many lectures from online free schools like Udacity, Coursera in subjects related to Artificial Intelligence, Building a Search Engine, Design and Analysis of Algorithm, Programming a Robotic Car, Programming Languages, Machine Learning, Software Engineering as a Service, WebApps Engineering, Compilers, Applied Crypotography etc. I also did some courses in Core and Advanced Java in my second year from training institute. I will also be taking course in Statistics, Databases, Discrete Mathematics from 25th June. Now I realized how vast is the field of Computer Science and how efficient you become on deciding algorithms and classifying problems into different subfields which have been thoroughly researched so you don't always do brute force thing or naive programming. Now this field has become kind of passion for me. Adding to the fact I am also doing my 6 months internship in software field in Texas Instruments where I am working on Automation and Algorithms. I also have some 5-6 good college level projects in Softwares and Robotics. I also like Electronics but only some fields like Operating System(this subject was there in Electronics also), Micro Processor, Digital, Computer Architecture, DSPs etc. I really want to pursue MS in some field of Computer Science. I am giving GRE in October/November. Till now I have good CG of around 9.4/10 and my 1 year in college is still left. Do I have any chance that some good University in US will consider me for MS in field related to computer science or Robotics. Also Can you suggest somethings that I can do during this 1 year to increase my chances for MS or should I apply for EECS(Electrical Engineering and Computer Science) and then I can shift more towards Computer Science as my major option. My main aim is to do Phd after Ms in CS if I am able to do that somehow. I know that I have to put much extra effort to understand things in MS than CS undergraduates but I will do that with my full dedication, also when I communicate with my college CS students or during my internship period I didn't feel that I am missing very much stuff that they know and was very comfortable during my internship with software employees.

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  • The State of the Internet -- Retail Edition

    - by David Dorf
    Over at Business Insider, there's a great presentation on the State of the Internet done in the Mary Meeker style.  Its 138 slides so I took the liberty of condensing it down to the 15 slides that directly apply to the retail industry.  However, I strongly recommend looking at the entire deck when you have time.  And while you're at it, Business Insider just launched a retail portal that's dedicated to retail industry content.  Please check it out as well.  My take-aways are below after the slide show. &amp;amp;amp;amp;lt;span id=&amp;amp;amp;amp;quot;XinhaEditingPostion&amp;amp;amp;amp;quot;&amp;amp;amp;amp;gt;&amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;gt; [Source: Business Insider] Here are a few things I took away from the statistics: Facebook and Twitter are in their infancy.  While all retailers should have social programs, search is still the driver and therefore should receive the lions share of investment.  Facebook referrals are up 92% year-over-year, but Google still does 80% of the referrals. E-commerce continues to grow at breakneck speed, but in-store commerce is still king. Stores are not showrooms yet.  And social commerce pure-plays like Gilt and Groupon are tiny but worthy of some attention. There are more smartphones than PCs on the internet, and the disparity will continue to grow. PC growth will be flat and Tablet use will continue to grow. Mobile accounts for 12% of all internet traffic. A quarter of smartphone sales come from China, so anyone with a presence there better have a strong mobile strategy. 38% of people have used their smartphone to make a purchase, and many use their smartphones inside stores.  Smartphones are a critical consumer tool for shopping. Mobile is starting to drive significant traffic to e-commerce sites, especially tablets.  Tablet strategies are crucial for retailers. Mobile payments from the likes of Paypal and Square are growing quickly.  It will be interesting to see how NFC plays in this area. Mobile operating systems are losing market share to iOS and Android.  I wonder in Microsoft can finally make a dent? The internet is being dominated by mobile devices, and retailers had better have a strong mobile strategy to meet consumer demand.

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  • ANTS CLR and Memory Profiler In Depth Review (Part 2 of 2 &ndash; Memory Profiler)

    - by ToStringTheory
    One of the things that people might not know about me, is my obsession to make my code as efficient as possible. Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind… In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve. One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well. In this review, I am going to cover some of the features of the ANTS memory profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program. I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction – Part 2 In my last post, I reviewed the feature packed Red Gate ANTS Performance Profiler.  Separate from the Red Gate Performance Profiler is the Red Gate ANTS Memory Profiler – a simple, easy to use utility for checking how your application is handling memory management…  A tool that I wish I had had many times in the past.  This post will be focusing on the ANTS Memory Profiler and its tool set. The memory profiler has a large assortment of features just like the Performance Profiler, with the new session looking nearly exactly alike: ANTS Memory Profiler Memory profiling is not something that I have to do very often…  In the past, the few cases I’ve had to find a memory leak in an application I have usually just had to trace the code of the operations being performed to look for oddities…  Sadly, I have come across more undisposed/non-using’ed IDisposable objects, usually from ADO.Net than I would like to ever see.  Support is not fun, however using ANTS Memory Profiler makes this task easier.  For this round of testing, I am going to use the same code from my previous example, using the WPF application. This time, I will choose the ‘Profile Memory’ option from the ANTS menu in Visual Studio, which launches the solution in its currently configured state/start-up project, and then launches the ANTS Memory Profiler to help.  It prepopulates all of the fields with the current project information, and all I have to do is select the ‘Start Profiling’ option. When the window comes up, it is actually quite barren, just giving ideas on how to work the profiler.  You start by getting to the point in your application that you want to profile, and then taking a ‘Memory Snapshot’.  This performs a full garbage collection, and snapshots the managed heap.  Using the same WPF app as before, I will go ahead and take a snapshot now. As you can see, ANTS is already giving me lots of information regarding the snapshot, however this is just a snapshot.  The whole point of the profiler is to perform an action, usually one where a memory problem is being noticed, and then take another snapshot and perform a diff between them to see what has changed.  I am going to go ahead and generate 5000 primes, and then take another snapshot: As you can see, ANTS is already giving me a lot of new information about this snapshot compared to the last.  Information such as difference in memory usage, fragmentation, class usage, etc…  If you take more snapshots, you can use the dropdown at the top to set your actual comparison snapshots. If you beneath the timeline, you will see a breadcrumb trail showing how best to approach profiling memory using ANTS.  When you first do the comparison, you start on the Summary screen.  You can either use the charts at the bottom, or switch to the class list screen to get to the next step.  Here is the class list screen: As you can see, it lists information about all of the instances between the snapshots, as well as at the bottom giving you a way to filter by telling ANTS what your problem is.  I am going to go ahead and select the Int16[] to look at the Instance Categorizer Using the instance categorizer, you can travel backwards to see where all of the instances are coming from.  It may be hard to see in this image, but hopefully the lightbox (click on it) will help: I can see that all of these instances are rooted to the application through the UI TextBlock control.  This image will probably be even harder to see, however using the ‘Instance Retention Graph’, you can trace an objects memory inheritance up the chain to see its roots as well.  This is a simple example, as this is simply a known element.  Usually you would be profiling an actual problem, and comparing those differences.  I know in the past, I have spotted a problem where a new context was created per page load, and it was rooted into the application through an event.  As the application began to grow, performance and reliability problems started to emerge.  A tool like this would have been a great way to identify the problem quickly. Overview Overall, I think that the Red Gate ANTS Memory Profiler is a great utility for debugging those pesky leaks.  3 Biggest Pros: Easy to use interface with lots of options for configuring profiling session Intuitive and helpful interface for drilling down from summary, to instance, to root graphs ANTS provides an API for controlling the profiler. Not many options, but still helpful. 2 Biggest Cons: Inability to automatically snapshot the memory by interval Lack of complete integration with Visual Studio via an extension panel Ratings Ease of Use (9/10) – I really do believe that they have brought simplicity to the once difficult task of memory profiling.  I especially liked how it stepped you further into the drilldown by directing you towards the best options. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do.  Features (7/10) – A really great set of features all around in the application, however, I would like to see some ability for automatically triggering snapshots based on intervals or framework level items such as events. Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good.  their people are friendly, helpful, and happy! UI / UX (9/10) – The interface is very easy to get around, and all of the options are easy to find.  With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (9/10) – Overall, I am happy with the Memory Profiler and its features, as well as with the service I received when working with the Red Gate personnel.  Thank you for reading up to here, or skipping ahead – I told you it would be shorter!  Please, if you do try the product, drop me a message and let me know what you think!  I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

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  • Enterprise Manager 12c: New DSS Demos Available

    - by Javier Puerta
    Enterprise Manager Cloud Control 12c Application Replay Demo Now Available! User Experience Monitoring with Enterprise Manager Cloud Control 12c and Real User Experience Insight 12R1 Now Available! Oracle Enterprise Manager Cloud Control 12c: Database Management Packs demo upgrade     Enterprise Manager Cloud Control 12c Application Replay Demo Now Available! We are pleased to announce the availability of the Oracle Application Replay demo that showcases some of the key capabilities of performing realistic, production scale testing of your web and packaged Oracle applications. This demo specifically focuses on capturing production web traffic from an E-Business Suite application and replaying the captured workload on a test E-Business Suite application to assess the impact of an application infrastructure change on the workload. The target audiences are application developers, quality assurance teams, IT managers and production control staff that deal in day-to-day change management activities and trouble shooting of production environments. Demo Highlights: Enterprise Manager 12c workflows for capturing application workload Seamless integration of Application Replay with Real User Experience Insight for application workload capture Enterprise Manager 12c centralized workflows for replaying captured application workloads in a test environment Demonstrates how to minimize risk when deploying a complex EBusiness Suite application infrastructure change. Rich reporting capability for performance analysis and problem detection User Experience Monitoring with Enterprise Manager Cloud Control 12c and Real User Experience Insight 12R1 Now Available! We are pleased to announce the availability of the Oracle Real User Experience Insight demo that showcases some of the key capabilities of user experience monitoring. This demo specifically focuses on business reporting, integrated performance diagnostics, tracking of customer journey’s through RUEI’s userflow tracking capabilities and it’s Key Performance Indicators tracking and configuration. Demo Highlights: Application-centric dashboard Integration with Oracle Enterprise Manager 12c – JVMD, ADP and BTM Session diagnostics and user session replay Monitoring through “Key Performance Indicators” (KPI) --- create alerts/incidents FUSION Application centric dashboards & integrated BI Oracle Enterprise Manager Cloud Control 12c: Database Management Packs demo upgrade DSS is pleased to announce an upgrade to the Oracle Enterprise Manager Cloud Control 12c: Database Management Packs demo. While retaining the content from the initial release of the demo—Diagnostic and Tuning Packs, Test Data Management and Data Masking, and Real Application Testing—the demo now includes a new Data Masking for Real Application Testing scenario. Demo Features: Diagnostic and Tuning Packs SQL Performance Analyzer Database Replay Data Masking Masking Real Application Testing workloads Testing pending Optimizer statistics Test Data Management

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  • Different Not Automatically Implies Better

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/11/05/154556.aspxRecently I was digging deeper why some WCF hosted workflow application did consume quite a lot of memory although it did basically only load a xaml workflow. The first tool of choice is Process Explorer or even better Process Hacker (has more options and the best feature copy&paste does work). The three most important numbers of a process with regards to memory are Working Set, Private Working Set and Private Bytes. Working set is the currently consumed physical memory (parts can be shared between processes e.g. loaded dlls which are read only) Private Working Set is the physical memory needed by this process which is not shareable Private Bytes is the number of non shareable which is only visible in the current process (e.g. all new, malloc, VirtualAlloc calls do create private bytes) When you have a bigger workflow it can consume under 64 bit easily 500MB for a 1-2 MB xaml file. This does not look very scalable. Under 64 bit the issue is excessive private bytes consumption and not the managed heap. The picture is quite different for 32 bit which looks a bit strange but it seems that the hosted VB compiler is a lot less memory hungry under 32 bit. I did try to repro the issue with a medium sized xaml file (400KB) which does contain 1000 variables and 1000 if which can be represented by C# code like this: string Var1; string Var2; ... string Var1000; if (!String.IsNullOrEmpty(Var1) ) { Console.WriteLine(“Var1”); } if (!String.IsNullOrEmpty(Var2) ) { Console.WriteLine(“Var2”); } ....   Since WF is based on VB.NET expressions you are bound to the hosted VB.NET compiler which does result in (x64) 140 MB of private bytes which is ca. 140 KB for each if clause which is quite a lot if you think about the actually present functionality. But there is hope. .NET 4.5 does allow now C# expressions for WF which is a major step forward for all C# lovers. I did create some simple patcher to “cross compile” my xaml to C# expressions. Lets look at the result: C# Expressions VB Expressions x86 x86 On my home machine I have only 32 bit which gives you quite exactly half of the memory consumption under 64 bit. C# expressions are 10 times more memory hungry than VB.NET expressions! I wanted to do more with less memory but instead it did consume a magnitude more memory. That is surprising to say the least. The workflow does initialize in about the same time under x64 and x86 where the VB code does it in 2s whereas the C# version needs 18s. Also nearly ten times slower. That is a too high price to pay for any bigger sized xaml workflow to convert from VB.NET to C# expressions. If I do reduce the number of expressions to 500 then it does need 400MB which is about half of the memory. It seems that the cost per if does rise linear with the number of total expressions in a xaml workflow.  Expression Language Cost per IF Startup Time C# 1000 Ifs x64 1,5 MB 18s C# 500 Ifs x64 750 KB 9s VB 1000 Ifs x64 140 KB 2s VB 500 Ifs x64 70 KB 1s Now we can directly compare two MS implementations. It is clear that the VB.NET compiler uses the same underlying structure but it has much higher offset compared to the highly inefficient C# expression compiler. I have filed a connect bug here with a harsher wording about recent advances in memory consumption. The funniest thing is that one MS employee did give an Azure AppFabric demo around early 2011 which was so slow that he needed to investigate with xperf. He was after startup time and the call stacks with regards to VB.NET expression compilation were remarkably similar. In fact I only found this post by googling for parts of my call stacks. … “C# expressions will be coming soon to WF, and that will have different performance characteristics than VB” … What did he know Jan 2011 what I did no know until today? ;-). He knew that C# expression will come but that they will not be automatically have better footprint. It is about time to fix that. In its current state C# expressions are not usable for bigger workflows. That also explains the headline for today. You can cheat startup time by prestarting workflows so that the demo looks nice and snappy but it does hurt scalability a lot since you do need much more memory than necessary. I did find the stacks by enabling virtual allocation tracking within XPerf which is still the best tool out there. But first you need to look at your process to check where the memory is hiding: For the C# Expression compiler you do not need xperf. You can directly dump the managed heap and check with a profiler of your choice. But if the allocations are happening on the Private Data ( VirtualAlloc ) you can find it with xperf. There is a nice video on channel 9 explaining VirtualAlloc tracking it in greater detail. If your data allocations are on the Heap it does mean that the C/C++ runtime did create a heap for you where all malloc, new calls do allocate from it. You can enable heap tracing with xperf and full call stack support as well which is doable via xperf like it is shown also on channel 9. Or you can use WPRUI directly: To make “Heap Usage” it work you need to set for your executable the tracing flags (before you start it). For example devenv.exe HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\devenv.exe DWORD TracingFlags 1 Do not forget to disable it after you did complete profiling the process or it will impact the startup time quite a lot. You can with xperf attach directly to a running process and collect heap allocation information from a gone wild process. Very handy if you need to find out what a process was doing which has arrived in a funny state. “VirtualAlloc usage” does work without explicitly enabling stuff for a specific process and is always on machine wide. I had issues on my Windows 7 machines with the call stack collection and the latest Windows 8.1 Performance Toolkit. I was told that WPA from Windows 8.0 should work fine but I do not want to downgrade.

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  • What books would I recommend?

    - by user12277104
    One of my mentees (I have three right now) said he had some time on his hands this Summer and was looking for good UX books to read ... I sigh heavily, because there is no shortage of good UX books to read. My bookshelves have titles by well-read authors like Nielsen, Norman, Tufte, Dumas, Krug, Gladwell, Pink, Csikszentmihalyi, and Roam. I have titles buy lesser-known authors, many whom I call friends, and many others whom I'll likely never meet. I have books on Excel pivot tables, typography, mental models, culture, accessibility, surveys, checklists, prototyping, Agile, Java, sketching, project management, HTML, negotiation, statistics, user research methods, six sigma, usability guidelines, dashboards, the effects of aging on cognition, UI design, and learning styles, among others ... many others. So I feel the need to qualify any book recommendations with "it depends ...", because it depends on who I'm talking to, and what they are looking for.  It's probably best that I also mention that the views expressed in this blog are mine, and may not necessarily reflect the views of Oracle. There. I'm glad I got that off my chest. For that mentee, who will be graduating with his MS HFID + MBA from Bentley in the Fall, I'll recommend this book: Universal Principles of Design -- this is a great book, which in its first edition held "100  ways to enhance usability, influence perception, increase appeal, make better design decisions, and teach through design." Granted, the second edition expanded that number to 125, but when I first found this book, I felt like I'd discovered the Grail. Its research-based principles are all laid out in 2 pages each, with lots of pictures and good references. A must-have for the new grad. Do I have recommendations for a book that will teach you how to conduct a usability test? Yes, three of them. To communicate what we do to management? Yes. To create personas? Yep -- two or three. Help you with UX in an Agile environment? You bet, I've got two I'd recommend. Create an excellent presentation? Uh hunh. Get buy-in from your team? Of course. There are a plethora of excellent UX books out there. But which ones I recommend ... well ... it depends. 

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  • Java EE 7 Survey Results!

    - by reza_rahman
    On November 8th, the Java EE EG posted a survey to gather broad community feedback on a number of critical open issues. For reference, you can find the original survey here. We kept the survey open for about three weeks until November 30th. To our delight, over 1100 developers took time out of their busy lives to let their voices be heard! The results of the survey were sent to the EG on December 12th. The subsequent EG discussion is available here. The exact summary sent to the EG is available here. We would like to take this opportunity to thank each and every one the individuals who took the survey. It is very appreciated, encouraging and worth it's weight in gold. In particular, I tried to capture just some of the high-quality, intelligent, thoughtful and professional comments in the summary to the EG. I highly encourage you to continue to stay involved, perhaps through the Adopt-a-JSR program. We would also like to sincerely thank java.net, JavaLobby, TSS and InfoQ for helping spread the word about the survey. Below is a brief summary of the results... APIs to Add to Java EE 7 Full/Web Profile The first question asked which of the four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. As the following graph shows, there was significant support for adding all the new APIs to the full profile: Support is relatively the weakest for Batch 1.0, but still good. A lot of folks saw WebSocket 1.0 as a critical technology with comments such as this one: "A modern web application needs Web Sockets as first class citizens" While it is clearly seen as being important, a number of commenters expressed dissatisfaction with the lack of a higher-level JSON data binding API as illustrated by this comment: "How come we don't have a Data Binding API for JSON" JCache was also seen as being very important as expressed with comments like: "JCache should really be that foundational technology on which other specs have no fear to depend on" The results for the Web Profile is not surprising. While there is strong support for adding WebSocket 1.0 and JSON-P 1.0 to the Web Profile, support for adding JCache 1.0 and Batch 1.0 is relatively weak. There was actually significant opposition to adding Batch 1. 0 (with 51.8% casting a 'No' vote). Enabling CDI by Default The second question asked was whether CDI should be enabled in Java EE environments by default. A significant majority of 73.3% developers supported enabling CDI, only 13.8% opposed. Comments such as these two reflect a strong general support for CDI as well as a desire for better Java EE alignment with CDI: "CDI makes Java EE quite valuable!" "Would prefer to unify EJB, CDI and JSF lifecycles" There is, however, a palpable concern around the performance impact of enabling CDI by default as exemplified by this comment: "Java EE projects in most cases use CDI, hence it is sensible to enable CDI by default when creating a Java EE application. However, there are several issues if CDI is enabled by default: scanning can be slow - not all libs use CDI (hence, scanning is not needed)" Another significant concern appears to be around backwards compatibility and conflict with other JSR 330 implementations like Spring: "I am leaning towards yes, however can easily imagine situations where errors would be caused by automatically activating CDI, especially in cases of backward compatibility where another DI engine (such as Spring and the like) happens to use the same mechanics to inject dependencies and in that case there would be an overlap in injections and probably an uncertain outcome" Some commenters such as this one attempt to suggest solutions to these potential issues: "If you have Spring in use and use javax.inject.Inject then you might get some unexpected behavior that could be equally confusing. I guess there will be a way to switch CDI off. I'm tempted to say yes but am cautious for this reason" Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations. A slight majority of 53.3% developers supported using @Inject consistently across JSRs. 28.8% said using custom injection annotations is OK, while 18.0% were not sure. The vast majority of commenters were strongly supportive of CDI and general Java EE alignment with CDI as illistrated by these comments: "Dependency Injection should be standard from now on in EE. It should use CDI as that is the DI mechanism in EE and is quite powerful. Having a new JSR specific DI mechanism to deal with just means more reflection, more proxies. JSRs should also be constructed to allow some of their objects Injectable. @Inject @TransactionalCache or @Inject @JMXBean etc...they should define the annotations and stereotypes to make their code less procedural. Dog food it. If there is a shortcoming in CDI for a JSR fix it and we will all be grateful" "We're trying to make this a comprehensive platform, right? Injection should be a fundamental part of the platform; everything else should build on the same common infrastructure. Each-having-their-own is just a recipe for chaos and having to learn the same thing 10 different ways" Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A significant majority of 62.3% developers supported expanding the use of @Stereotype, only 13.3% opposed. A majority of commenters supported the idea as well as the theme of general CDI/Java EE alignment as expressed in these examples: "Just like defining new types for (compositions of) existing classes, stereotypes can help make software development easier" "This is especially important if many EJB services are decoupled from the EJB component model and can be applied via individual annotations to Java EE components. @Stateless is a nicely compact annotation. Code will not improve if that will have to be applied in the future as @Transactional, @Pooled, @Secured, @Singlethreaded, @...." Some, however, expressed concerns around increased complexity such as this commenter: "Could be very convenient, but I'm afraid if it wouldn't make some important class annotations less visible" Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE... A very solid 96.3% of developers wanted to expand interceptor use to all Java EE components. 35.7% even wanted to expand interceptors to other Java EE managed classes. Most developers (54.9%) were not sure if there is any place that injection is supported that should not support interceptors. 32.8% thought any place that supports injection should also support interceptors. Only 12.2% were certain that there are places where injection should be supported but not interceptors. The comments reflected the diversity of opinions, generally supportive of interceptors: "I think interceptors are as fundamental as injection and should be available anywhere in the platform" "The whole usage of interceptors still needs to take hold in Java programming, but it is a powerful technology that needs some time in the Sun. Basically it should become part of Java SE, maybe the next step after lambas?" A distinct chain of thought separated interceptors from filters and listeners: "I think that the Servlet API already provides a rich set of possibilities to hook yourself into different Servlet container events. I don't find a need to 'pollute' the Servlet model with the Interceptors API"

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  • Data Source Connection Pool Sizing

    - by Steve Felts
    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:"Times New Roman","serif";} One of the most time-consuming procedures of a database application is establishing a connection. The connection pooling of the data source can be used to minimize this overhead.  That argues for using the data source instead of accessing the database driver directly. Configuring the size of the pool in the data source is somewhere between an art and science – this article will try to move it closer to science.  From the beginning, WLS data source has had an initial capacity and a maximum capacity configuration values.  When the system starts up and when it shrinks, initial capacity is used.  The pool can grow to maximum capacity.  Customers found that they might want to set the initial capacity to 0 (more on that later) but didn’t want the pool to shrink to 0.  In WLS 10.3.6, we added minimum capacity to specify the lower limit to which a pool will shrink.  If minimum capacity is not set, it defaults to the initial capacity for upward compatibility.   We also did some work on the shrinking in release 10.3.4 to reduce thrashing; the algorithm that used to shrink to the maximum of the currently used connections or the initial capacity (basically the unused connections were all released) was changed to shrink by half of the unused connections. The simple approach to sizing the pool is to set the initial/minimum capacity to the maximum capacity.  Doing this creates all connections at startup, avoiding creating connections on demand and the pool is stable.  However, there are a number of reasons not to take this simple approach. When WLS is booted, the deployment of the data source includes synchronously creating the connections.  The more connections that are configured in initial capacity, the longer the boot time for WLS (there have been several projects for parallel boot in WLS but none that are available).  Related to creating a lot of connections at boot time is the problem of logon storms (the database gets too much work at one time).   WLS has a solution for that by setting the login delay seconds on the pool but that also increases the boot time. There are a number of cases where it is desirable to set the initial capacity to 0.  By doing that, the overhead of creating connections is deferred out of the boot and the database doesn’t need to be available.  An application may not want WLS to automatically connect to the database until it is actually needed, such as for some code/warm failover configurations. There are a number of cases where minimum capacity should be less than maximum capacity.  Connections are generally expensive to keep around.  They cause state to be kept on both the client and the server, and the state on the backend may be heavy (for example, a process).  Depending on the vendor, connection usage may cost money.  If work load is not constant, then database connections can be freed up by shrinking the pool when connections are not in use.  When using Active GridLink, connections can be created as needed according to runtime load balancing (RLB) percentages instead of by connection load balancing (CLB) during data source deployment. Shrinking is an effective technique for clearing the pool when connections are not in use.  In addition to the obvious reason that there times where the workload is lighter,  there are some configurations where the database and/or firewall conspire to make long-unused or too-old connections no longer viable.  There are also some data source features where the connection has state and cannot be used again unless the state matches the request.  Examples of this are identity based pooling where the connection has a particular owner and XA affinity where the connection is associated with a particular RAC node.  At this point, WLS does not re-purpose (discard/replace) connections and shrinking is a way to get rid of the unused existing connection and get a new one with the correct state when needed. So far, the discussion has focused on the relationship of initial, minimum, and maximum capacity.  Computing the maximum size requires some knowledge about the application and the current number of simultaneously active users, web sessions, batch programs, or whatever access patterns are common.  The applications should be written to only reserve and close connections as needed but multiple statements, if needed, should be done in one reservation (don’t get/close more often than necessary).  This means that the size of the pool is likely to be significantly smaller then the number of users.   If possible, you can pick a size and see how it performs under simulated or real load.  There is a high-water mark statistic (ActiveConnectionsHighCount) that tracks the maximum connections concurrently used.  In general, you want the size to be big enough so that you never run out of connections but no bigger.   It will need to deal with spikes in usage, which is where shrinking after the spike is important.  Of course, the database capacity also has a big influence on the decision since it’s important not to overload the database machine.  Planning also needs to happen if you are running in a Multi-Data Source or Active GridLink configuration and expect that the remaining nodes will take over the connections when one of the nodes in the cluster goes down.  For XA affinity, additional headroom is also recommended.  In summary, setting initial and maximum capacity to be the same may be simple but there are many other factors that may be important in making the decision about sizing.

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  • Can't access some websites using Ubuntu 13.10

    - by Adame Doe
    Something's wrong with Ubuntu. Since I've upgraded to 13.10, I can't access some websites for no apparent reason. I've tried everything imaginable to solve this problem : Made sure that MTUs are the same, Disabled IPv6 in both the network manager and used browsers, Deactivated my network keys, DMZed my computer, Used other DNS like Google and OpenDNS, Checked that no firewall was running my computer ... And it's the same result. I even tried to reinstall Ubuntu a couple of times, but no luck. The most annoying thing about it is I can't access wordpress.org! So, there's no way it could be an ISP restriction of some kind. When I use a VPN, I can access pretty much anything. I'm really frustrated because I have to use wordpress.org very often. Any clue? ifconfig adame@adame-ws:~$ ifconfig eth0 Link encap:Ethernet HWaddr 00:26:18:3d:b0:7c inet addr:10.42.0.1 Bcast:10.42.0.255 Mask:255.255.255.0 inet6 addr: fe80::226:18ff:fe3d:b07c/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:8024 errors:0 dropped:0 overruns:0 frame:0 TX packets:7966 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:684480 (684.4 KB) TX bytes:616608 (616.6 KB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:8222 errors:0 dropped:0 overruns:0 frame:0 TX packets:8222 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:568269 (568.2 KB) TX bytes:568269 (568.2 KB) wlan0 Link encap:Ethernet HWaddr 00:19:70:40:85:eb inet addr:192.168.2.3 Bcast:192.168.2.255 Mask:255.255.255.0 inet6 addr: fe80::219:70ff:fe40:85eb/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1464 Metric:1 RX packets:123705 errors:0 dropped:0 overruns:0 frame:0 TX packets:98141 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:94963545 (94.9 MB) TX bytes:10387470 (10.3 MB) /etc/hosts 127.0.0.1 localhost 127.0.1.1 adame-ws ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters tracepath wordpress.org 1: adame-ws.local 0.092ms pmtu 1500 1: 192.168.2.1 1.300ms asymm 2 1: 192.168.2.1 1.060ms asymm 2 2: no reply 3: no reply 4: no reply 5: no reply 6: no reply 7: no reply 8: no reply ... keep on going like that ping wordpress.org adame@adame-ws:~$ ping wordpress.org PING wordpress.org (66.155.40.250) 56(84) bytes of data. --- wordpress.org ping statistics --- 10 packets transmitted, 0 received, 100% packet loss, time 9071ms

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  • Application stuck in TCP retransmit

    - by SandeepJ
    I am running Linux kernel 3.13 (Ubuntu 14.04) on two Virtual Machines each of which operates inside two different servers running ESXi 5.1. There is a zeromq client-server application running between the two VMs. After running for about 10-30 minutes, this application consistently hangs due to inability to retransmit a lost packet. When I run the same setup over Ubuntu 12.04 (Linux 3.11), the application never fails If you notice below, "ss" (socket statistics) shows 1 packet lost, sk_wmem_queued of 14110 (i.e. w14110) and a high rto (120000). State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB 0 12350 192.168.2.122:41808 192.168.2.172:55550 timer:(on,16sec,10) uid:1000 ino:35042 sk:ffff880035bcb100 <- skmem:(r0,rb648720,t0,tb1164800,f2274,w14110,o0,bl0) ts sack cubic wscale:7,7 rto:120000 rtt:7.5/3 ato:40 mss:8948 cwnd:1 ssthresh:21 send 9.5Mbps unacked:1 retrans:1/10 lost:1 rcv_rtt:1476 rcv_space:37621 Since this has happened so consistently, I was able to capture the TCP log in wireshark. I found that the packet which is lost does get retransmitted and even acknowledged by the TCP in the other OS (the sequence number is seen in the ACK), but the sender doesn't seem to understand this ACK and continues retransmitting. MTU is 9000 on both virtual machines and througout the route. The packets being sent are large in size. As I said earlier, this does not happen on Ubuntu 12.04 (kernel 3.11). So I did a diff on the TCP config options (seen via "sysctl -a |grep tcp ") between 14.04 and 12.04 and found the following differences. I also noticed that net.ipv4.tcp_mtu_probing=0 in both configurations. Left side is 3.11, right side is 3.13 <<net.ipv4.tcp_abc = 0 <<net.ipv4.tcp_cookie_size = 0 <<net.ipv4.tcp_dma_copybreak = 4096 14c11 << net.ipv4.tcp_early_retrans = 2 --- >> net.ipv4.tcp_early_retrans = 3 17c14 << net.ipv4.tcp_fastopen = 0 >> net.ipv4.tcp_fastopen = 1 20d16 << net.ipv4.tcp_frto_response = 0 26,27c22 << net.ipv4.tcp_max_orphans = 16384 << net.ipv4.tcp_max_ssthresh = 0 >> net.ipv4.tcp_max_orphans = 4096 29,30c24,25 << net.ipv4.tcp_max_tw_buckets = 16384 << net.ipv4.tcp_mem = 94377 125837 188754 >> net.ipv4.tcp_max_tw_buckets = 4096 >> net.ipv4.tcp_mem = 23352 31138 46704 34a30 >> net.ipv4.tcp_notsent_lowat = -1 My question to the networking experts on this forum : Are there any other debugging tools or options I can install/enable to dig further into why this TCP retransmit failure is occurring so consistently ? Are there any configuration changes which might account for this weird behaviour.

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  • Why shouldn't I be using public variables in my Java class?

    - by Omega
    In school, I've been told many times to stop using public for my variables. I haven't asked why yet. This question: Are Java's public fields just a tragic historical design flaw at this point? seems kinda related to this. However, they don't seem to discuss why is it "wrong", but instead focus on how can they use them instead. Look at this (unfinished) class: public class Reporte { public String rutaOriginal; public String rutaNueva; public int bytesOriginales; public int bytesFinales; public float ganancia; /** * Constructor para objetos de la clase Reporte */ public Reporte() { } } No need to understand Spanish. All this class does is hold some statistics (those public fields) and then do some operations with them (later). I will also need to be modifying those variables often. But well, since I've been told not to use public, this is what I ended up doing: public class Reporte { private String rutaOriginal; private String rutaNueva; private int bytesOriginales; private int bytesFinales; private float ganancia; /** * Constructor para objetos de la clase Reporte */ public Reporte() { } public String getRutaOriginal() { return rutaOriginal; } public String getRutaNueva() { return rutaNueva; } public int getBytesOriginales() { return bytesOriginales; } public int getBytesFinales() { return bytesFinales; } public float getGanancia() { return ganancia; } public void setRutaOriginal(String rutaOriginal) { this.rutaOriginal = rutaOriginal; } public void setRutaNueva(String rutaNueva) { this.rutaNueva = rutaNueva; } public void setBytesOriginales(int bytesOriginales) { this.bytesOriginales = bytesOriginales; } public void setBytesFinales(int bytesFinales) { this.bytesFinales = bytesFinales; } public void setGanancia(float ganancia) { this.ganancia = ganancia; } } Looks kinda pretty. But seems like a waste of time. Google searches about "When to use public in Java" and "Why shouldn't I use public in Java" seem to discuss about a concept of mutability, although I'm not really sure how to interpret such discussions. I do want my class to be mutable - all the time.

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  • Best Practice for captcha based protection against D.O.S to Nginx Proxy

    - by user325320
    The idea is explained here In simple words, Nginx Proxy plays the role of load balance and transmits the HTTP/HTTPS requests to servers. If the number of request times within a certain period from an individual IP exceeds a threshold, it will trigger a captcha for the upcoming requests. And the end-user must input the correct captcha code before he can continue to access the site. Do you know any open source / free NGINX module for this usage? I searched on the Internet and here is one of them: https://github.com/snbuback/nginx seems it needs modification. Any suggestion / experience is welcome, thank you

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  • PHP/APC fatal error, apc_mmap: mmap failed

    - by Sudowned
    I'm seeing some intermittent CPU usage spikes to 100%, sort of correlated to these log entries: [27-Feb-2012 13:29:29] PHP Fatal error: PHP Startup: apc_mmap: mmap failed: in Unknown on line 0 [27-Feb-2012 13:29:30] PHP Fatal error: PHP Startup: apc_mmap: mmap failed: in Unknown on line 0 [27-Feb-2012 13:29:31] PHP Fatal error: PHP Startup: apc_mmap: mmap failed: in Unknown on line 0 [27-Feb-2012 13:29:31] PHP Fatal error: PHP Startup: apc_mmap: mmap failed: in Unknown on line 0 phpinfo() indicates that APC is set up, and as far as I can tell this error doesn't cause visible 500 errors on the live site, which is a WordPress install that gets about 600k views monthly. Google's been unhelpful so far, and I was hoping that someone here had some insight as to what's causing this and how to fix it. Curiously, this error only shows up /usr/local/apache2/logs/error_log and not the error_log for the cpanel-configured site.

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  • How to resolve "svn: Can't find a temporary directory: Internal error"?

    - by HorusKol
    I have already googled the message, and I have plenty of disk space available on the SVN server (it's about 4% usage of 150 GB). I have noticed that when I try echo $TMPDIR at the command prompt on the SVN server I get nothing. What is making this a little confusing is that I only get this message from one location when I do an svn diff (that I've tested so far) - this error is not coming up when I try from three other computers (one of which is testing against the exact same repository, the other two are different repositories on the same svn server). About the only difference I can see is that the broken working copy is connecting to the server by an IP address where all the others are using a server name (although this resolves over DNS to the same IP Address). I'm hoping that I don't have to scratch the broken working copy and checkout a new one - unfortunately, this is a legacy project and not all changes have been properly revisioned.

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  • iftop - how to generate text file with its output?

    - by mickula
    iftop is great tool to view almost live bandwidth usage distinguished by source-ip source-port destination-ip destination port. I'm using it to see which client's ip is using most bandwidth. Now I would like to store output somewhere. iftop uses ncurses so iftop > log.txt does not work as expected, result file is not readable. Is there any tool like this which can be used to pipe output to a text file? Thanks for your replies.

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