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  • SQL Server IO handling mechanism can be severely affected by high CPU usage

    - by sqlworkshops
    Are you using SSD or SAN / NAS based storage solution and sporadically observe SQL Server experiencing high IO wait times or from time to time your DAS / HDD becomes very slow according to SQL Server statistics? Read on… I need your help to up vote my connect item – https://connect.microsoft.com/SQLServer/feedback/details/744650/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage. Instead of taking few seconds, queries could take minutes/hours to complete when CPU is busy.In SQL Server when a query / request needs to read data that is not in data cache or when the request has to write to disk, like transaction log records, the request / task will queue up the IO operation and wait for it to complete (task in suspended state, this wait time is the resource wait time). When the IO operation is complete, the task will be queued to run on the CPU. If the CPU is busy executing other tasks, this task will wait (task in runnable state) until other tasks in the queue either complete or get suspended due to waits or exhaust their quantum of 4ms (this is the signal wait time, which along with resource wait time will increase the overall wait time). When the CPU becomes free, the task will finally be run on the CPU (task in running state).The signal wait time can be up to 4ms per runnable task, this is by design. So if a CPU has 5 runnable tasks in the queue, then this query after the resource becomes available might wait up to a maximum of 5 X 4ms = 20ms in the runnable state (normally less as other tasks might not use the full quantum).In case the CPU usage is high, let’s say many CPU intensive queries are running on the instance, there is a possibility that the IO operations that are completed at the Hardware and Operating System level are not yet processed by SQL Server, keeping the task in the resource wait state for longer than necessary. In case of an SSD, the IO operation might even complete in less than a millisecond, but it might take SQL Server 100s of milliseconds, for instance, to process the completed IO operation. For example, let’s say you have a user inserting 500 rows in individual transactions. When the transaction log is on an SSD or battery backed up controller that has write cache enabled, all of these inserts will complete in 100 to 200ms. With a CPU intensive parallel query executing across all CPU cores, the same inserts might take minutes to complete. WRITELOG wait time will be very high in this case (both under sys.dm_io_virtual_file_stats and sys.dm_os_wait_stats). In addition you will notice a large number of WAITELOG waits since log records are written by LOG WRITER and hence very high signal_wait_time_ms leading to more query delays. However, Performance Monitor Counter, PhysicalDisk, Avg. Disk sec/Write will report very low latency times.Such delayed IO handling also occurs to read operations with artificially very high PAGEIOLATCH_SH wait time (with number of PAGEIOLATCH_SH waits remaining the same). This problem will manifest more and more as customers start using SSD based storage for SQL Server, since they drive the CPU usage to the limits with faster IOs. We have a few workarounds for specific scenarios, but we think Microsoft should resolve this issue at the product level. We have a connect item open – https://connect.microsoft.com/SQLServer/feedback/details/744650/sql-server-io-handling-mechanism-can-be-severely-affected-by-high-cpu-usage - (with example scripts) to reproduce this behavior, please up vote the item so the issue will be addressed by the SQL Server product team soon.Thanks for your help and best regards,Ramesh MeyyappanHome: www.sqlworkshops.comLinkedIn: http://at.linkedin.com/in/rmeyyappan

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  • Java EE Web Services study guides

    - by Marthin
    I´m going for the Java EE 6 Web Services Developer certificat but I´m having a hard time to find som solid study guides and mock exams. I already have the JPA and very soon EJB cert so i´m not new to this stuff but I´v looked at coderanch and other places but all information seems a bit outdated. So any tips for books, mock exams free or not, tutorials or other guides would be very much appreciated. EDIT: I will of course read all JSR´s needed.

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  • Ubuntu 12.04 GUI doesn't load after Virtualbox crash

    - by Itamar Katz
    I have Ubuntu 12.04 64 bit installed as a virtual OS in Virtualbox (the host is windows 7). The Virtualbox data file is on a usb drive that lost connection to the PC while a session was running. Now when I try to start the Ubuntu virtual OS, I get a terminal login screen, but no GUI. When I try to login I get the message sh: 1: cannot create /var/run/motd.new: Directory nonexistent Any suggestions? Can I recover the system?

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  • Google I/O 2012 - Measuring the End-to-End Value of Your App

    Google I/O 2012 - Measuring the End-to-End Value of Your App Neil Rhodes, Nick Mihailovski, Mike Kwong We've rethought mobile app analytics from the ground up. If you are a mobile app developer, come see what's new from the land of Google Analytics; Understand how to measure the end-to-end value of your app, and improve its performance to drive usage and retention. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 69 4 ratings Time: 01:04:12 More in Science & Technology

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  • Where should libraries be placed, in windows?

    - by Gabriel Diaconescu
    I have just moved from Linux to Windows, and I have to use the Zend Framework library. Where should the library be placed? Directly on C drive Create a lib folder like C:/lib/ Create a lib folder in my user folder I am wondering if there is a classic folder where these kind of libraries are placed. Update:I am asking about the location on my own standpoint. The Zend Framework library is a PHP framework.

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  • Computer Games Technolgy or Software Engineering?

    - by Suleman Anwar
    I'm in the last year of my college and going to university next year. Could you tell me what the difference between Software Engineering and Computer Games Technology is? I know a bit of both but don't know the actual difference. I'm kind off in a dilemma between these two. I want to be a programmer, I'd love to go into gaming but I heard getting a job within a computer games company is really hard.

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  • SQL Server Optimizer Malfunction?

    - by Tony Davis
    There was a sharp intake of breath from the audience when Adam Machanic declared the SQL Server optimizer to be essentially "stuck in 1997". It was during his fascinating "Query Tuning Mastery: Manhandling Parallelism" session at the recent PASS SQL Summit. Paraphrasing somewhat, Adam (blog | @AdamMachanic) offered a convincing argument that the optimizer often delivers flawed plans based on assumptions that are no longer valid with today’s hardware. In 1997, when Microsoft engineers re-designed the database engine for SQL Server 7.0, SQL Server got its initial implementation of a cost-based optimizer. Up to SQL Server 2000, the developer often had to deploy a steady stream of hints in SQL statements to combat the occasionally wilful plan choices made by the optimizer. However, with each successive release, the optimizer has evolved and improved in its decision-making. It is still prone to the occasional stumble when we tackle difficult problems, join large numbers of tables, perform complex aggregations, and so on, but for most of us, most of the time, the optimizer purrs along efficiently in the background. Adam, however, challenged further any assumption that the current optimizer is competent at providing the most efficient plans for our more complex analytical queries, and in particular of offering up correctly parallelized plans. He painted a picture of a present where complex analytical queries have become ever more prevalent; where disk IO is ever faster so that reads from disk come into buffer cache faster than ever; where the improving RAM-to-data ratio means that we have a better chance of finding our data in cache. Most importantly, we have more CPUs at our disposal than ever before. To get these queries to perform, we not only need to have the right indexes, but also to be able to split the data up into subsets and spread its processing evenly across all these available CPUs. Improvements such as support for ColumnStore indexes are taking things in the right direction, but, unfortunately, deficiencies in the current Optimizer mean that SQL Server is yet to be able to exploit properly all those extra CPUs. Adam’s contention was that the current optimizer uses essentially the same costing model for many of its core operations as it did back in the days of SQL Server 7, based on assumptions that are no longer valid. One example he gave was a "slow disk" bias that may have been valid back in 1997 but certainly is not on modern disk systems. Essentially, the optimizer assesses the relative cost of serial versus parallel plans based on the assumption that there is no IO cost benefit from parallelization, only CPU. It assumes that a single request will saturate the IO channel, and so a query would not run any faster if we parallelized IO because the disk system simply wouldn’t be able to handle the extra pressure. As such, the optimizer often decides that a serial plan is lower cost, often in cases where a parallel plan would improve performance dramatically. It was challenging and thought provoking stuff, as were his techniques for driving parallelism through query logic based on subsets of rows that define the "grain" of the query. I highly recommend you catch the session if you missed it. I’m interested to hear though, when and how often people feel the force of the optimizer’s shortcomings. Barring mistakes, such as stale statistics, how often do you feel the Optimizer fails to find the plan you think it should, and what are the most common causes? Is it fighting to induce it toward parallelism? Combating unexpected plans, arising from table partitioning? Something altogether more prosaic? Cheers, Tony.

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  • Alcatel-Lucent: Enterprise 2.0: The Top 5 Things I would Do Over

    - by Kellsey Ruppel
    Happy Monday! Does anyone else feel as if the weekend went entirely too quickly? At least for those of us in the United States, we have the 4th of July Holiday next week to look forward to This week on the blog, we are going to focus on "WebCenter by Example" and highlight best practices from customers and partners. I recently came across this article and I think this is a great example of how we can learn from one another when it comes to social collaboration adoption. Do you agree with Jem? What things or best practices have you learned in your organizations?  By Jem Janik, Enterprise community manager, Alcatel-Lucent  Not so long ago, Engage, the Alcatel-Lucent employee social network and collaboration platform, celebrated its third birthday. With more than 25,000 members actively interacting each month, Engage has been a big enough success that it’s been the subject of external articles, and often those of us who helped launch it will go out and speak about what aspects contributed to that success. Hindsight is still 20/20 and what it takes to successfully launch an enterprise 2.0 community is fairly well-known now.  Today I want to tell you what I suspect you really want to know about.  As the enterprise community manager for Engage, after three years in, what are the top 5 things I wish we (and I mostly mean me) could do over? #5 Define your analytics solution from the start There is so much to do when you launch a community and initially growing it without complete chaos is quite a task.  It doesn’t take too long to get to a point where you want to focus your continued efforts in growing company collaboration.  Do people truly talk across regional boundaries or have we shifted siloed conversations to a new platform.  Is there one organization that doesn’t interact with another? If you are lucky you’ll have someone in your community team well versed in the world of databases and SQL queries, but it takes time to figure out what backend analytics data actually means. Professional support can be expensive and it may be hard to justify later as it typically has the community manager as the only main customer.  Figure out what you think you’ll want to know and how to get it early on. The sooner the better even if it doesn’t seem that critical at the time. #4 Lobbies guide you to the right places One piece of feedback that comes up more and more as we keep growing Engage is it’s hard to find stuff, or new people are not sure where to start. Something we’re doing now is defining some general topic areas of interest to be like “lobbies” into the platform and some common hashtags to go with them. I liken this to walking into a large medical or professional building for the first time.  There are hundreds of offices, and you look to a sign in the lobby to get guided to the right place for you.  We’re building that sign for members now, but again we missed the boat as the majority of the company has had their initial Engage experience. #3 Clean up, clean up, clean up Knowledge work and folksonomies are messy! The day we opened the doors to Engage I would have said we should keep everything ever created in Engage with an argument that it was a window into our collective knowledge so nothing should go.  Well, 6000+ groups and 200,000+ pieces of content later, I’ve changed my mind.  As previously mentioned, with too much “stuff” the system can be overwhelming to new members and it makes it harder to get what you’re looking for.   Do we need that help document about a tool we no longer have? NO!  Do we need that group that had 1 document and 2 discussions in the last two years? NO! Should we only have one group about a given topic instead of 4?  YES! Last fall, Engage defined a cleanup process for groups not used for a long time.  We also formed a volunteer cleaning army who are extra eyes on the hunt for “stuff” that should be updated, merged, or deleted.  It’s better late than never, but in line with what’s becoming a theme I wish these efforts had started earlier. #2 Communications & local community management One of the most important aspects of my job is to make sure people who should be talking to each other are actually doing it.  Connecting people to the other people they should know, the groups they should join, a piece of content that shouldn’t be missed.   I have worked both inside and outside of communications teams, and they are the best informed people in your company.  They know when something big is coming, how it impacts employees, how it fits with strategy, who else knows more, etc.  Having communications professionals who are power users can help scale up community management because they are already so well connected.  They also need to have the platform skills to pay attention without suffering email overload, how to grab someone’s attention, etc.  I wish I’d had figured this out much earlier.  If I had I would have groomed more communications colleagues into advocates and power members right at the start. #1 Grooming advocates vs. natural advocates I’ve just alluded to this above already. The very best advocates are those who naturally embrace your platform and automatically start to see new ways to work within it.  Those advocates seem to come out of the woodwork naturally since some of them are early adopters.  Not surprisingly, our best advocates today are those same people who were willing to come kick the tires when the community was completely empty.  Unfortunately, we didn’t get a global spread of those natural advocates.  I did ask around when we first launched for other people who might be good candidates, but didn’t push too hard as there were so many other things to get ready.  That was a mistake.  If I could get a redo I would have formally asked for people to be assigned where there were gaps and groomed them into an advocate.  Today as we find new advocates to fill the gaps, people are hesitant as the initial set has three years of practice are ahead of the curve power members; it definitely would have been easier earlier on. As fairly early adopters to corporate scale enterprise collaboration, there hasn’t been a roadmap to follow as we’ve grown Engage, which is part of the fun! It’s clear a lot of issues are more easily tackled the earlier you identify and begin to correct them, and I’ve identified the main five I wish I could redo.  In the spirit of collaboration, I hope someone else learns from my mistakes! View the original article by Jem here. 

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  • Delete Data From Your Hardrive With DBAN

    This week, I felt the need to re publish an article that my web designer wrote a few years ago. It was written about formatting files from a hard drive to make them unrecoverable. This is very import... [Author: Chris Holgate - Computers and Internet - April 09, 2010]

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  • Time for Some Bleach, Disinfectant, and What Else? [Image]

    - by Asian Angel
    Sometimes working in Tech Support requires a lot of courage (and cleaning supplies)… That’s not a disgusting Mac keyboard. THIS is a disgusting Mac keyboard. [FIXED] [via Reddit - Tech Support Gore] HTG Explains: What The Windows Event Viewer Is and How You Can Use It HTG Explains: How Windows Uses The Task Scheduler for System Tasks HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows?

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  • Post 12.04 Update, stuck on splash screen

    - by Lawrence
    I updated to 12.04 a couple of weeks ago and I haven't started up Ubuntu until now. On start up the computer gets stuck on the splash screen. I am a beginner in all of this linux mechanics. I've seen many people post about relatively the same problem but I have a hard time following. I am using Wubi and running it along side Windows Starter on a Toshiba netbook. Thanks for bearing with my unfamiliarity haha,

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  • SQL SERVER – Backup SQL databases to Box or SkyDrive

    - by Pinal Dave
    To ensure your SQL Server or Azure databases remain safe, you should backup your databases periodically. And it is important to store the backups in a reliable location. Microsoft SkyDrive currently offers 7GB free, Box offers 5GB free – both are reliable and it is simple to send your backups there. SQLBackupAndFTP in it’s latest version 9 added the option to backup to SkyDrive and Box ( in addition to local/network folder, NAS drive, FTP, Dropbox, Google Drive and Amazon S3). Just select the databases that you’d like to backup and select to store the backups in SkyDrive or Box. Below I will show you how to do it in details Select databases to backup First connect to your SQL Server or Azure Sql Database. Then select the databases you’d like to backup. Connect to SkyDrive or Box cloud If you have a free version of SQLBackupAndFTP Box destination is included, but SkyDrive destination will be disabled as it is available in the Standard version or above. Click “Try now” to get 30 days trial on all options On the “SkyDrive Settings” form you’ll need to authorize SQLBackupAndFTP to access your SkyDrive. Click “Authorize…” to open SkyDrive authorization page in your browser, sign in your to SkyDrive account and click at “Allow” . On the next page you will see the field with authorization code. Copy it to the clipboard. Box operation is just the same. After that return to SQLBackupAndFTP, paste the authorization code and click “OK” . After you are authorized, you can enter the path to a backup folder. SQLBackupAndFTP will create the folder if it does not exist. That’s all what has to be done to backup to SkyDrive or Box cloud.  You can now click on “Run Now” button to test this job. Conclusion Whatever is your preference for storing SQL backups, it is easy with SQLBackupAndFTP. Note that at the time of this writing they are running a very rare promotion on volume licenses: 5–9 licenses: 20% off 10–19 licenses: 35% off more than 20 licenses: 50% off Please let me know your favorite options for storing the backups. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • How far has a bug pushed you? [closed]

    - by Darknight
    When debugging (hard to find) bugs, I know I've personally gotten so frustrated as to lash out on the keyboard and shout profanities at the monitor. I have repeatability witnessed co-workers throw their computer mouse off the table in anger and frustration. What is the furthest a bastard of bug has ever pushed you? EDIT: Hehehe :D it would seem this bug, er I mean post has pushed the guys to close it... Oh well, very very interesting answers anyway.

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  • Biml Workshop presented by Varigence and Linchpin People

    Business Intelligence Markup Language (Biml) automates your BI patterns and eliminates the manual repetition that consumes most of your time. On October 15th come see why BI professionals around the world think Biml is the future of data integration and BI. Need to compare and sync database schemas?Let SQL Compare do the hard work. ”With the productivity I'll get out of this tool, it's like buying time.” Robert Sondles. Download a free trial.

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  • Cant install 12.04.1 or 12.10 in Asus GT75VW laptop

    - by Software companies in perth
    I got this new laptop that comes with a 256 GB ssd drive 128 GB are used for the preinstalled Windows 7 I want to install Ubuntu on the other 128 Gb. I first installed 12.10, it worked and booted once into the OS bu then it started booting onto a black screen so i tried with 12.04.1, i tried installing it a few times with the normal and alternate installer but after saying the installation was OK, it boots onto this distorted graphics screen with a purpelish background where you can't do anything.... What do i do?

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  • Commerce, Anyway You Want It

    - by David Dorf
    I believe our industry is finally starting to realize the importance of letting consumers determine how, when, and where to interact with retailers.  Over the last few months I've seen several articles discussing the importance of removing the barriers between existing channels. Paula Rosenblum of RSR first brought the term omni-channel to my attention back in September. She stated, "omni-channel retail isn’t the merging of channels – rather, it’s the use of all possible channels (present and future) to enhance the customer experience in a profitable way." I added to her thoughts in this blog posting in which I said, "For retailers to provide an omni-channel experience, there needs to be one logical representation of products, prices, promotions, and customers across all channels. The only thing that varies is the presentation of the content based on the delivery mechanism (e.g. shelf labels, mobile phone, web site, print, etc.) and often these mechanisms can be combined in various ways." More recently Brian Walker of Gartner suggested we stop using the term multi-channel and begin thinking more about consumer touch-points. "It is time for organizations to leave their channel-oriented ways behind, and enter the era of agile commerce--optimizing their people, processes and technology to serve today's empowered, ever-connected customers across this rapidly evolving set of customer touch points." Now Jason Goldberg, better known as RetailGeek, says we should start breaking down the channel silos by re-casting the VP of E-Commerce as the VP of Digital Marketing, and change his/her focus to driving sales across all channels using digital media. This logic is based on the fact that consumers switch between channels, or touch-points as Brian prefers, as part of their larger buying process. Today's smart consumer leverages the Web, mobile, and stores to provide the best shopping experience, so retailers need to make this easier. Regardless of what we call it, the key take-away is that "multi-channel" is not only an antiquated term but also an idea who's time has passed.  Today, retailers must look at e-commerce, m-commerce, f-commerce, catalogs, and traditional store sales collectively and through the consumers' eyes.  The goal is not to drive sales through each channel but rather to just drive sales -- using whatever method the customer prefers.  There really should be just one cart.

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  • Books / blogs that discuss service excellence? [closed]

    - by Bogdan Gavril
    I'm looking for information about service excellence topics such as: 0 downtime deployment how to deal with versioning (backward and forward compatibility) environment strategies (how many staging envs ? etc.) performance testing testing in production monitoring I am looking at the Microsoft stack, but the concepts should be the same everywhere. Do you have any recommendations of books or blogs on the subject? PS: I have found some good articles from I.M.Wright's "Hard Code" blog. Anything else?

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  • Why do programming languages allow shadowing/hiding of variables and functions?

    - by Simon
    Many of the most popular programming languges (such as C++, Java, Python etc.) have the concept of hiding / shadowing of variables or functions. When I've encountered hiding or shadowing they have been the cause of hard to find bugs and I've never seen a case where I found it necessary to use these features of the languages. To me it would seem better to disallow hiding and shadowing. Does anybody know of a good use of these concepts?

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