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• Pair Programming, for or against? [on hold]

  - by user1037729

  I believe it has many advantages over individual programming: Pros By pairing senior with relatively junior staff, the more junior can get up to speed with both project and computing experience, and the senior will re-think the problem in order to communicate with the junior, thus re-checking his own thinking (rubber duck principle!). At least 2 people will know about any single piece of work, if one person is away the other can cover, or if some one leaves a project knowledge transfer is easier. Two brains on a complex task is more effective, communication keeps the work free flowing and provides redundancy in decision making. Code is effectively reviewed as its being written, no need for a separate reviewing phase which requires a context switch as someone who has not been working on the piece in question would be required to understand and review the related code. Reviewing code on your own which you haven't written or architected is not fun, hence counter productive. Cons Less bandwith for performing tasks, lets say we have 4 devs, pair programming requires 2 devs per task, so we would be doing 2 tasks concurrently as a posed to 4. I believe this "Con" does not stand up as the pair programmed task would complete sooner and comes with a review built in for free! Ie the pair programming task would be more efficient and thus free up resources earlier. Less flexibility to chop and change tasks as two developers are tied into a task, when flexibility is required this could be a problem.

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• JavaOne Technology Conference Is Coming to Russia

  - by Tori Wieldt

  JavaOne Russia 17-18 AprilRussian Academy of Sciences, MoscowRegister Now JavaOne and Oracle Develop 2012 Russia offers a wide variety of sessions, hands-on labs, keynotes, demos, and the opportunity to network with developer peers. If you’re looking for in-depth sessions on Java technologies and tools, this is the conference for you. Your registration also gets you into Oracle Develop sessions as well, so you can learn about application servers, cloud development and, of course, database development. The JavaOne Russia tracks are:Client-Side Technologies and Rich User ExperiencesLearn about developments in Java for the desktop and practices for building rich, immersive, and powerful user experiences across multiple hardware platforms and form factors. Core Java PlatformDiscover the latest innovations in Java virtual machines. Get deep technical explanations in security and networking and enhancements that allow dynamic programming languages to drive Java platform adoption. Java EE Web Profile, Platform Technologies, Web Services, and the Cloud Update your knowledge on topics such as Web application development, persistence, security, and transactions. This track will also address modularity, enterprise caching, Web sockets, and internet identity. Mobile, Java Card, Embedded, and DevicesThis track is devoted to Java technology as the ultimate platform for mobile computing. It also covers embedded and device usages of Java technologies, including Java SE, Java ME, Java Card, and JavaFX. Share this event: #oracleRU

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• New Certification Exam: "Oracle Database 12c: SQL Fundamentals" Released (1Z0-061)

  - by Brandye Barrington

  Oracle Certification begins testing this week for the new Oracle Database 12c Administrator Certified Associate (OCA) certification.  Testing for the Oracle Database 12c: SQL Fundamentals (1Z0-061) exam is now underway. Visit pearsonvue.com/oracle and register for exam 1Z0-061. You can get all preparation details, including exam objectives, number of questions, time allotments, and pricing on the Oracle Certification Website. Earning the Oracle Database 12c Administrator Certified Associate (OCA) credential demonstrates that you carry the foundational knowledge and skills needed to administer the Oracle Database, and sets the stage for your future progression to Oracle Database 12c Administrator Certified Professional (OCP). With Oracle Database 12c, you will experience the benefits of an Oracle Database that is re-engineered for Cloud computing. Multitenant architecture brings enterprises unprecedented hardware and software efficiencies, performance and manageability benefits, and fast and efficient Cloud provisioning. Oracle Database 12c certifications emphasize the full set of skills that DBAs need in today's competitive marketplace. Be among the first to obtain this ground breaking new Oracle Certified Associate (OCA) certification by registering for this exam today. QUICK LINKS Certification Path: Oracle Database 12c Administrator Certified Associate (OCA) Certification Exam: Oracle Database 12c: SQL Fundamentals (1Z0-061) Registration: pearsonvue.com/oracle

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• Impact of Service Oriented Architecture (SOA) on Business and IT Operations

  The impact of Service Oriented Architecture (SOA) on business and IT operations varies from company to company. I think more and more companies are starting to view SOA as just another technology that they can incorporate in an existing or new system. One of the driving factors in using SOA is the reduction in maintenance costs and decrease in the time needed to bring products to market. The reductions in costs, and reduced turnaround time can be directly converted in to increased profitability due to less expenditures that are needed in order to maintain or create new systems. My personal perspective on SOA is that it is great for what it is actually intended to do. SOA allows systems to be distributed across networks or even the world while ensuring enterprise processing consistency, data integrity and preventing code duplication. This being said a lot of preparation and work goes into properly designing and implementing an SOA especially if an enterprise wants to take full advantage of its benefits. Even though SOA has recently gotten a lot of hype about its benefits it does not a perfect fit for all situations. At the end of the day SOA is just another tool in my tool belt that I can pull from to create solutions that meet the business’s needs. Based on current industry trends SOA appears to be a very solid technology to use moving forward, especially as more and more companies shift towards cloud based computing. It is important to remember that SOA is one of many technologies that can be used in creating business solutions and I think more time will be spent in the future evaluating if SOA is the right technology for a solution once the initial hype of SOA has calmed down.

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• What is the R Language?

  - by TATWORTH

  I encountered the R Language recently with O'Reilly books and while from the context I knew it was a language for dealing with statistics, doing a web search for the support web site was futile. However I have now located the web site and it is at http://www.r-project.org/R is a free language available for a number of platforms including windows. CRAN mirrors are available at a number of locations worldwide.Here is the official description:"R is a language and environment for statistical computing and graphics. It is a GNU project which is similar to the S language and environment which was developed at Bell Laboratories (formerly AT&T, now Lucent Technologies) by John Chambers and colleagues. R can be considered as a different implementation of S. There are some important differences, but much code written for S runs unaltered under R. R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, ...) and graphical techniques, and is highly extensible. The S language is often the vehicle of choice for research in statistical methodology, and R provides an Open Source route to participation in that activity. One of R's strengths is the ease with which well-designed publication-quality plots can be produced, including mathematical symbols and formulae where needed. Great care has been taken over the defaults for the minor design choices in graphics, but the user retains full control. R is available as Free Software under the terms of the Free Software Foundation's GNU General Public License in source code form. It compiles and runs on a wide variety of UNIX platforms and similar systems (including FreeBSD and Linux), Windows and MacOS."

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• How to Integrate Dropbox with Pages, Keynote, and Numbers on iPad

  - by The Geek

  The iWork apps are some of the best apps on the iPad, and each show just how powerful a touchscreen device can be with the most basic of computing functions. In fact, there’s not much to dislike about the iWork apps, except for one thing: importing and exporting files. You can open documents from email attachments, download them from websites, or import them from other apps like Dropbox. Once you’ve opened your file in Pages, Keynote, or Numbers on iPad, though, you can only send it via email, upload it to a WebDAV server or Apple’s iDisk service, or wait to sync it with iTunes on your computer. Most other iOS office apps don’t offer nearly as many features as the iWork apps, but they do offer deep integration with Dropbox which makes it easy to view and edit your documents no matter where you are. Dropbox is the most popular file sync and sharing solution, and makes it absolutely painless to share folders with anyone around the world and keep your computers in sync. That is, computers and applications that integrate with Dropbox. However, you don’t need to give up on using Dropbox with iWork apps on iPad. Today we’re going to look at how you can enable WebDAV compatibility on your Dropbox account to let Pages integrate nearly the whole way with Dropbox. It’s not a perfect solution, but it’s much better than the default setup. So let’s get started Latest Features How-To Geek ETC How to Integrate Dropbox with Pages, Keynote, and Numbers on iPad RGB? CMYK? Alpha? What Are Image Channels and What Do They Mean? How to Recover that Photo, Picture or File You Deleted Accidentally How To Colorize Black and White Vintage Photographs in Photoshop How To Get SSH Command-Line Access to Windows 7 Using Cygwin The How-To Geek Video Guide to Using Windows 7 Speech Recognition Stylebot Customizes Web Pages in Chrome, Now Has Downloadable Styles Blackberry, Dell, Apple, and Motorola Tablets Compared [Infographic] Encrypt Your Google Search Queries Vintage Posters Showcase the History of Tech Advertising Google Cloud Print Extension Lets You Print Doc/PDF/Txt Files from Web Sites Hack a $10 Flashlight into an Ultra-bright Premium One

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• Packing for JavaOne

  - by Tori Wieldt

  While you are packing for JavaOne, here are some things to remember to bring:1) A Jacket!While October is considered the summer in San Francisco, the heat only lasts a day or two. The fog can roll in any day, and it can be chilly (and maybe even rain).2) Your Oracle LoginMake sure your have your Oracle.com account log in details with you when you arrive onsite in San Francisco.  This is the username and password you used/created for your JavaOne 2012 registration.  You'll need these to check in and get your badge as well as to gain access to My Account and Schedule Builder onsite at the event. 3) Walking ShoesYou'll want comfortable and practical shoes as this city requires lots of walking and has lots of hills.4) Thumb DrivesWhen sharing cool code, nothing beats sneaker-net. That said, practice safe computing. 5) Consider Downloading a Ride-Sharing Service AppSideCar, Lyft, Uber and RelayRides are taking SF by storm, and are popular alternative to yellow taxis. These are unregulated ride-sharing services, so ride at your own risk. Hipster Tips for SF 1) Don't call it Frisco.2) If you wear shorts, don't complain about how cold it is.3) Bright colored clothes are for tourists. Locals wear black. 4) The most fun ice-cream flavors in town are at Humphry-Slocombe. Check out "secret breakfast."5) The Mission is hip.6) Don't expect there to be a Starbuck's or anything besides a great view at the other side of the Golden Gate bridge.7) SF has seasons, they are just more subtle.

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• is Java free for mobile development?

  - by exTrace101

  Q1. I would like to know if it's free for a developer (I mean, if I have to pay no royalties to Sun/Oracle) to develop (Android) mobile apps in Java? After reading this snippet about use of Java field, I'm getting the impression that Java is not free for mobile development, is that right? .."General Purpose Desktop Computers and Servers" means computers, including desktop and laptop computers, or servers, used for general computing functions under end user control (such as but not specifically limited to email, general purpose Internet browsing, and office suite productivity tools). The use of Software in systems and solutions that provide dedicated functionality (other than as mentioned above) or designed for use in embedded or function-specific software applications, for example but not limited to: Software embedded in or bundled with industrial control systems, wireless mobile telephones, wireless handheld devices, netbooks, kiosks, TV/STB, Blu-ray Disc devices, telematics and network control switching equipment, printers and storage management systems, and other related systems are excluded from this definition and not licensed under this Agreement... and from http://www.excelsiorjet.com/embedded/ Notice : The Java SE Embedded technology license currently prohibits the use of Java SE in cell phones. Q2. how come these plethora of Android Java developers aren't paying Sun/Oracle a dime?

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• A Better Way to Plan, Execute and Manage Enterprise Architecture

  - by JuergenKress

  IT Strategies from Oracle is an authorized library of guidelines and reference architectures that will help you better plan, execute, and manage your enterprise architecture and IT initiatives. The IT Strategies from Oracle library offers two types of best practice documents: practitioner guides containing pragmatic advice and approaches, and reference architectures containing the proven technology patterns to jumpstart your initiative. The IT Strategies from Oracle library can help you establish a reliable set of principles and standards to guide your use of Oracle technology. We will expand this library over time across all of Oracle's technologies. Today, you can access: Overview documents providing an introduction to all the resources available in the library and best practices maturity models Oracle Reference Architectures covering the application infrastructure foundation, management and monitoring, security, software engineering, service-oriented integration, service orientation, user interaction, engineered systems, and a master glossary. Enterprise Technology Strategies for Service-Oriented Architecture offering practitioner guides on creating a SOA roadmap, frameworks for governance, determining ROI, identifying services, software engineering, and white papers. Enterprise Technology Strategies for Event-Driven Architecture offering practitioner guides on creating an EDA roadmap and reference architectures on an EDA foundation and EDA infrastructure. Enterprise Technology Strategies for Business Process Management including practitioner guides on creating a BPM roadmap, business process engineering, governance, and reference architectures on a BPM foundation and BPM infrastructure. Enterprise Technology Strategies for Cloud Computing including reference architectures on a Cloud foundation and Cloud infrastructure. Enterprise Technology Strategies for Business Analytics includes a practitioner guide for creating a BA roadmap, and reference architectures for a BA foundation and BA infrastructure. Get the Oracle Enterprise Architecture content here. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: Architecture,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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• Web Service Standard Complexity

  Are we over-standardizing web services and hindering their adoption? No, and in fact I feel that it is helping its adoption in the modern corporate world. Standards, although they can be daunting and tedious, provide a universal framework to which we all can operate in and around. These frameworks provide a common interface for all of to use when interaction with various computing environments so that data can be transfer freely.  Standards are protocols in which computers communicate with one another. If we take this to the living world, the united nations hires interprets for all each countries dignitaries so that they can understand what other countries are talking about. Imagine if the president of the United States wanted to talk to the ruler of China. How would these to communicate? The interpreter would translate data back and forth acting as in intermediary using both standard American English and Chinese. Without knowing the standards in either language no one would be able to communicate. Even though we work within the framework of standards does not mean that we are stuck with these standards. As technology evolves all standards will be out of touch, and when this occurs standards need to be refactored or replaced with new standards that are current with the technology at that time. How else are we as developers and the technology going to grow? What do you guys think?

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• Integrating Amazon EC2 in Java via NetBeans IDE

  - by Geertjan

  Next, having looked at Amazon Associates services and Amazon S3, let's take a look at Amazon EC2, the elastic compute cloud which provides remote computing services. I started by launching an instance of Ubuntu Server 14.04 on Amazon EC2, which looks a bit like this in the on-line AWS Management Console, though I whitened out most of the details: Now that I have at least one running instance available on Amazon EC2, it makes sense to use the services that are integrated into NetBeans IDE:  I created a new application with one class, named "AmazonEC2Demo". Then I dragged the "describeInstances" service that you see above, with the mouse, into the class. Then the IDE automatically created all the other files you see below, i.e., 4 Java classes and one properties file: In the properties file, register the access ID and secret keys. These are read by the other generated Java classes. Signing and authentication are done automatically by the code that is generated, i.e., there's nothing generic you need to do and you can immediately begin working on your domain-specific code. Finally, you're now able to rewrite the code in "AmazonEC2Demo" to connect to Amazon EC2 and obtain information about your running instance: public class AmazonEC2Demo { public static void main(String[] args) { String instanceId1 = "i-something"; RestResponse result; try { result = AmazonEC2Service.describeInstances(instanceId1); System.out.println(result.getDataAsString()); } catch (IOException ex) { Logger.getLogger(AmazonEC2Demo.class.getName()).log(Level.SEVERE, null, ex); } } } From the above, you'll receive a chunk of XML with data about the running instance, it's name, status, dates, etc. In other words, you're now ready to integrate Amazon EC2 features directly into the applications you're writing, without very much work to get started. Within about 5 minutes, you're working on your business logic, rather than on the generic code that anyone needs when integrating with Amazon EC2.

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• EOFs in Solaris 11

  - by nospam(at)example.com (Joerg Moellenkamp)

  Well ? from comments here and elsewhere, the two most worst things seemed to be the the removal of 32-bit support and removal of support for certain components. Just to set things into perspective: Solaris 10 was released 2005, the newsest class of machines not supported by it were the Ultra1. This one was released 1995. The UltraSPARC-Systems not able to run on Solaris 11 were released 2001. Well ? we have 2011 now ?. Regarding 32-bit support: Well ? I don't think "playing around with Solaris on old gear" is the problem. At first, most people are playing around with virtual machines. But there is something different: 64-bit computing was introduced for x86 in 2003 (yes ? it's really that old). I think this move is more hurting to the people using boards with the first-gen Intel Atom "Silverthorne" as small file servers. And then Solaris 10 won't disappear with Solaris 11

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• 2012 Oracle Fusion Innovation Awards - Part 1

  - by Michelle Kimihira

  Author: Moazzam Chaudry This year we recognized 29 customers for their innovative use of Oracle Fusion Middleware and their significant results. The winners were selected across 8 product categories from 11 countries spanning diverse industries around the world. This is a two-part blog series. The 2012 Fusion Middleware Innovation Awards winners were announced at OOW on October 2nd by Hasan Rizvi (EVP Fusion Middleware and Java development), Amit Zavery (VP Product Management) and Ed Zou (VP Product Management) to an audience that included press, analysts and customers. Winners were selected based on the uniqueness of their business case, business benefits, level of impact relative to the size of the organization, complexity and magnitude of implementation, and the originality of architecture. The program is in its 6th year and this year, we are excited to have received over 250 submissions from customers around the globe. The winners were selected by a panel of internal and external judges; it was a difficult time selecting this year's most innovative projects. Judges scored each entry across multiple scoring categories. This year, winning use cases for Fusion Middleware include: Improve customer experience by monitoring real-time and simplifying user experience of tens of millions of customer Drive social enagement through social media channels in fields, including healthcare, harness big data by analyzing and improving visibility across 60M+customers and hundreds of terabytes of data Enable mobile adoption by delivering mobile news experience to 50% of the Australian population, embrace cloud computing by delivering hospitality services to 3000+ hotels and monitoring services to hospitals, and optimize criticial processes such as, remarketing cars through tens of thousands of dealers On Monday's blog, we will talk about the winners in each category and what customers had to say in the customer panel. Congratulations to the 2012 Oracle Fusion Innovation Award winners:  

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• Are my negative internship experiences representative of the real world? [closed]

  - by attemptAtAnonymity

  I'm curious if my current experiences as an intern are representative of actual industry. As background, I'm through the better part of two computing majors and a math major at a major university; I've aced every class and adored all of them, so I'd like to think that I'm not terrible at programming. I got an internship with one of the major software companies, and half way through now I've been shocked at the extraordinarily low quality of code. Comments don't exist, it's all spaghetti code, and everything that could be wrong is even worse. I've done a ton of tutoring/TAing, so I'm very used to reading bad code, but the major industry products I've been seeing trump all of that. I work 10-12 hours a day and never feel like I'm getting anywhere, because it's endless hours of trying to figure out an undocumented API or determine the behavior of some other part of the (completely undocumented) product. I've left work hating the job every day so far, and I desperately want to know if this is what is in store for the rest of my life. Did I draw a short straw on internships (the absurdly large paychecks imply that it's not a low quality position), or is this what the real world is like?

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• Are my negative internship experiences respresentative of the real world?

  - by attemptAtAnonymity

  I'm curious if my current experiences as an intern are representative of actual industry. As background, I'm through the better part of two computing majors and a math major at a major university; I've aced every class and adored all of them, so I'd like to think that I'm not terrible at programming. I got an internship with one of the major software companies, and half way through now I've been shocked at the extraordinarily low quality of code. Comments don't exist, it's all spaghetti code, and everything that could be wrong is even worse. I've done a ton of tutoring/TAing, so I'm very used to reading bad code, but the major industry products I've been seeing trump all of that. I work 10-12 hours a day and never feel like I'm getting anywhere, because it's endless hours of trying to figure out an undocumented API or determine the behavior of some other part of the (completely undocumented) product. I've left work hating the job every day so far, and I desperately want to know if this is what is in store for the rest of my life. Did I draw a short straw on internships (the absurdly large paychecks imply that it's not a low quality position), or is this what the real world is like?

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• SQL SERVER – SSMS: Disk Usage Report

  - by Pinal Dave

  Let us start with humor!  I think we the series on various reports, we come to a logical point. We covered all the reports at server level. This means the reports we saw were targeted towards activities that are related to instance level operations. These are mostly like how a doctor diagnoses a patient. At this point I am reminded of a dialog which I read somewhere: Patient: Doc, It hurts when I touch my head. Doc: Ok, go on. What else have you experienced? Patient: It hurts even when I touch my eye, it hurts when I touch my arms, it even hurts when I touch my feet, etc. Doc: Hmmm … Patient: I feel it hurts when I touch anywhere in my body. Doc: Ahh … now I get it. You need a plaster to your finger John. Sometimes the server level gives an indicator to what is happening in the system, but we need to get to the root cause for a specific database. So, this is the first blog in series where we would start discussing about database level reports. To launch database level reports, expand selected server in Object Explorer, expand the Databases folder, and then right-click any database for which we want to look at reports. From the menu, select Reports, then Standard Reports, and then any of database level reports. In this blog, we would talk about four “disk” reports because they are similar: Disk Usage Disk Usage by Top Tables Disk Usage by Table Disk Usage by Partition Disk Usage This report shows multiple information about the database. Let us discuss them one by one.  We have divided the output into 5 different sections. Section 1 shows the high level summary of the database. It shows the space used by database files (mdf and ldf). Under the hood, the report uses, various DMVs and DBCC Commands, it is using sys.data_spaces and DBCC SHOWFILESTATS. Section 2 and 3 are pie charts. One for data file allocation and another for the transaction log file. Pie chart for “Data Files Space Usage (%)” shows space consumed data, indexes, allocated to the SQL Server database, and unallocated space which is allocated to the SQL Server database but not yet filled with anything. “Transaction Log Space Usage (%)” used DBCC SQLPERF (LOGSPACE) and shows how much empty space we have in the physical transaction log file. Section 4 shows the data from Default Trace and looks at Event IDs 92, 93, 94, 95 which are for “Data File Auto Grow”, “Log File Auto Grow”, “Data File Auto Shrink” and “Log File Auto Shrink” respectively. Here is an expanded view for that section. If default trace is not enabled, then this section would be replaced by the message “Trace Log is disabled” as highlighted below. Section 5 of the report uses DBCC SHOWFILESTATS to get information. Here is the enhanced version of that section. This shows the physical layout of the file. In case you have In-Memory Objects in the database (from SQL Server 2014), then report would show information about those as well. Here is the screenshot taken for a different database, which has In-Memory table. I have highlighted new things which are only shown for in-memory database. The new sections which are highlighted above are using sys.dm_db_xtp_checkpoint_files, sys.database_files and sys.data_spaces. The new type for in-memory OLTP is ‘FX’ in sys.data_space. The next set of reports is targeted to get information about a table and its storage. These reports can answer questions like: Which is the biggest table in the database? How many rows we have in table? Is there any table which has a lot of reserved space but its unused? Which partition of the table is having more data? Disk Usage by Top Tables This report provides detailed data on the utilization of disk space by top 1000 tables within the Database. The report does not provide data for memory optimized tables. Disk Usage by Table This report is same as earlier report with few difference. First Report shows only 1000 rows First Report does order by values in DMV sys.dm_db_partition_stats whereas second one does it based on name of the table. Both of the reports have interactive sort facility. We can click on any column header and change the sorting order of data. Disk Usage by Partition This report shows the distribution of the data in table based on partition in the table. This is so similar to previous output with the partition details now. Here is the query taken from profiler. SELECT row_number() OVER (ORDER BY a1.used_page_count DESC, a1.index_id) AS row_number ,      (dense_rank() OVER (ORDER BY a5.name, a2.name))%2 AS l1 ,      a1.OBJECT_ID ,      a5.name AS [schema] ,       a2.name ,       a1.index_id ,       a3.name AS index_name ,       a3.type_desc ,       a1.partition_number ,       a1.used_page_count * 8 AS total_used_pages ,       a1.reserved_page_count * 8 AS total_reserved_pages ,       a1.row_count FROM sys.dm_db_partition_stats a1 INNER JOIN sys.all_objects a2  ON ( a1.OBJECT_ID = a2.OBJECT_ID) AND a1.OBJECT_ID NOT IN (SELECT OBJECT_ID FROM sys.tables WHERE is_memory_optimized = 1) INNER JOIN sys.schemas a5 ON (a5.schema_id = a2.schema_id) LEFT OUTER JOIN  sys.indexes a3  ON ( (a1.OBJECT_ID = a3.OBJECT_ID) AND (a1.index_id = a3.index_id) ) WHERE (SELECT MAX(DISTINCT partition_number) FROM sys.dm_db_partition_stats a4 WHERE (a4.OBJECT_ID = a1.OBJECT_ID)) >= 1 AND a2.TYPE <> N'S' AND  a2.TYPE <> N'IT' ORDER BY a5.name ASC, a2.name ASC, a1.index_id, a1.used_page_count DESC, a1.partition_number Using all of the above reports, you should be able to get the usage of database files and also space used by tables. I think this is too much disk information for a single blog and I hope you have used them in the past to get data. Do let me know if you found anything interesting using these reports in your environments. 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 Tagged: SQL Reports

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• The blocking nature of aggregates

  - by Rob Farley

  I wrote a post recently about how query tuning isn’t just about how quickly the query runs – that if you have something (such as SSIS) that is consuming your data (and probably introducing a bottleneck), then it might be more important to have a query which focuses on getting the first bit of data out. You can read that post here.  In particular, we looked at two operators that could be used to ensure that a query returns only Distinct rows. and The Sort operator pulls in all the data, sorts it (discarding duplicates), and then pushes out the remaining rows. The Hash Match operator performs a Hashing function on each row as it comes in, and then looks to see if it’s created a Hash it’s seen before. If not, it pushes the row out. The Sort method is quicker, but has to wait until it’s gathered all the data before it can do the sort, and therefore blocks the data flow. But that was my last post. This one’s a bit different. This post is going to look at how Aggregate functions work, which ties nicely into this month’s T-SQL Tuesday. I’ve frequently explained about the fact that DISTINCT and GROUP BY are essentially the same function, although DISTINCT is the poorer cousin because you have less control over it, and you can’t apply aggregate functions. Just like the operators used for Distinct, there are different flavours of Aggregate operators – coming in blocking and non-blocking varieties. The example I like to use to explain this is a pile of playing cards. If I’m handed a pile of cards and asked to count how many cards there are in each suit, it’s going to help if the cards are already ordered. Suppose I’m playing a game of Bridge, I can easily glance at my hand and count how many there are in each suit, because I keep the pile of cards in order. Moving from left to right, I could tell you I have four Hearts in my hand, even before I’ve got to the end. By telling you that I have four Hearts as soon as I know, I demonstrate the principle of a non-blocking operation. This is known as a Stream Aggregate operation. It requires input which is sorted by whichever columns the grouping is on, and it will release a row as soon as the group changes – when I encounter a Spade, I know I don’t have any more Hearts in my hand. Alternatively, if the pile of cards are not sorted, I won’t know how many Hearts I have until I’ve looked through all the cards. In fact, to count them, I basically need to put them into little piles, and when I’ve finished making all those piles, I can count how many there are in each. Because I don’t know any of the final numbers until I’ve seen all the cards, this is blocking. This performs the aggregate function using a Hash Match. Observant readers will remember this from my Distinct example. You might remember that my earlier Hash Match operation – used for Distinct Flow – wasn’t blocking. But this one is. They’re essentially doing a similar operation, applying a Hash function to some data and seeing if the set of values have been seen before, but before, it needs more information than the mere existence of a new set of values, it needs to consider how many of them there are. A lot is dependent here on whether the data coming out of the source is sorted or not, and this is largely determined by the indexes that are being used. If you look in the Properties of an Index Scan, you’ll be able to see whether the order of the data is required by the plan. A property called Ordered will demonstrate this. In this particular example, the second plan is significantly faster, but is dependent on having ordered data. In fact, if I force a Stream Aggregate on unordered data (which I’m doing by telling it to use a different index), a Sort operation is needed, which makes my plan a lot slower. This is all very straight-forward stuff, and information that most people are fully aware of. I’m sure you’ve all read my good friend Paul White (@sql_kiwi)’s post on how the Query Optimizer chooses which type of aggregate function to apply. But let’s take a look at SQL Server Integration Services. SSIS gives us a Aggregate transformation for use in Data Flow Tasks, but it’s described as Blocking. The definitive article on Performance Tuning SSIS uses Sort and Aggregate as examples of Blocking Transformations. I’ve just shown you that Aggregate operations used by the Query Optimizer are not always blocking, but that the SSIS Aggregate component is an example of a blocking transformation. But is it always the case? After all, there are plenty of SSIS Performance Tuning talks out there that describe the value of sorted data in Data Flow Tasks, describing the IsSorted property that can be set through the Advanced Editor of your Source component. And so I set about testing the Aggregate transformation in SSIS, to prove for sure whether providing Sorted data would let the Aggregate transform behave like a Stream Aggregate. (Of course, I knew the answer already, but it helps to be able to demonstrate these things). A query that will produce a million rows in order was in order. Let me rephrase. I used a query which produced the numbers from 1 to 1000000, in a single field, ordered. The IsSorted flag was set on the source output, with the only column as SortKey 1. Performing an Aggregate function over this (counting the number of rows per distinct number) should produce an additional column with 1 in it. If this were being done in T-SQL, the ordered data would allow a Stream Aggregate to be used. In fact, if the Query Optimizer saw that the field had a Unique Index on it, it would be able to skip the Aggregate function completely, and just insert the value 1. This is a shortcut I wouldn’t be expecting from SSIS, but certainly the Stream behaviour would be nice. Unfortunately, it’s not the case. As you can see from the screenshots above, the data is pouring into the Aggregate function, and not being released until all million rows have been seen. It’s not doing a Stream Aggregate at all. This is expected behaviour. (I put that in bold, because I want you to realise this.) An SSIS transformation is a piece of code that runs. It’s a physical operation. When you write T-SQL and ask for an aggregation to be done, it’s a logical operation. The physical operation is either a Stream Aggregate or a Hash Match. In SSIS, you’re telling the system that you want a generic Aggregation, that will have to work with whatever data is passed in. I’m not saying that it wouldn’t be possible to make a sometimes-blocking aggregation component in SSIS. A Custom Component could be created which could detect whether the SortKeys columns of the input matched the Grouping columns of the Aggregation, and either call the blocking code or the non-blocking code as appropriate. One day I’ll make one of those, and publish it on my blog. I’ve done it before with a Script Component, but as Script components are single-use, I was able to handle the data knowing everything about my data flow already. As per my previous post – there are a lot of aspects in which tuning SSIS and tuning execution plans use similar concepts. In both situations, it really helps to have a feel for what’s going on behind the scenes. Considering whether an operation is blocking or not is extremely relevant to performance, and that it’s not always obvious from the surface. In a future post, I’ll show the impact of blocking v non-blocking and synchronous v asynchronous components in SSIS, using some of LobsterPot’s Script Components and Custom Components as examples. When I get that sorted, I’ll make a Stream Aggregate component available for download.

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• The blocking nature of aggregates

  - by Rob Farley

  I wrote a post recently about how query tuning isn’t just about how quickly the query runs – that if you have something (such as SSIS) that is consuming your data (and probably introducing a bottleneck), then it might be more important to have a query which focuses on getting the first bit of data out. You can read that post here.  In particular, we looked at two operators that could be used to ensure that a query returns only Distinct rows. and The Sort operator pulls in all the data, sorts it (discarding duplicates), and then pushes out the remaining rows. The Hash Match operator performs a Hashing function on each row as it comes in, and then looks to see if it’s created a Hash it’s seen before. If not, it pushes the row out. The Sort method is quicker, but has to wait until it’s gathered all the data before it can do the sort, and therefore blocks the data flow. But that was my last post. This one’s a bit different. This post is going to look at how Aggregate functions work, which ties nicely into this month’s T-SQL Tuesday. I’ve frequently explained about the fact that DISTINCT and GROUP BY are essentially the same function, although DISTINCT is the poorer cousin because you have less control over it, and you can’t apply aggregate functions. Just like the operators used for Distinct, there are different flavours of Aggregate operators – coming in blocking and non-blocking varieties. The example I like to use to explain this is a pile of playing cards. If I’m handed a pile of cards and asked to count how many cards there are in each suit, it’s going to help if the cards are already ordered. Suppose I’m playing a game of Bridge, I can easily glance at my hand and count how many there are in each suit, because I keep the pile of cards in order. Moving from left to right, I could tell you I have four Hearts in my hand, even before I’ve got to the end. By telling you that I have four Hearts as soon as I know, I demonstrate the principle of a non-blocking operation. This is known as a Stream Aggregate operation. It requires input which is sorted by whichever columns the grouping is on, and it will release a row as soon as the group changes – when I encounter a Spade, I know I don’t have any more Hearts in my hand. Alternatively, if the pile of cards are not sorted, I won’t know how many Hearts I have until I’ve looked through all the cards. In fact, to count them, I basically need to put them into little piles, and when I’ve finished making all those piles, I can count how many there are in each. Because I don’t know any of the final numbers until I’ve seen all the cards, this is blocking. This performs the aggregate function using a Hash Match. Observant readers will remember this from my Distinct example. You might remember that my earlier Hash Match operation – used for Distinct Flow – wasn’t blocking. But this one is. They’re essentially doing a similar operation, applying a Hash function to some data and seeing if the set of values have been seen before, but before, it needs more information than the mere existence of a new set of values, it needs to consider how many of them there are. A lot is dependent here on whether the data coming out of the source is sorted or not, and this is largely determined by the indexes that are being used. If you look in the Properties of an Index Scan, you’ll be able to see whether the order of the data is required by the plan. A property called Ordered will demonstrate this. In this particular example, the second plan is significantly faster, but is dependent on having ordered data. In fact, if I force a Stream Aggregate on unordered data (which I’m doing by telling it to use a different index), a Sort operation is needed, which makes my plan a lot slower. This is all very straight-forward stuff, and information that most people are fully aware of. I’m sure you’ve all read my good friend Paul White (@sql_kiwi)’s post on how the Query Optimizer chooses which type of aggregate function to apply. But let’s take a look at SQL Server Integration Services. SSIS gives us a Aggregate transformation for use in Data Flow Tasks, but it’s described as Blocking. The definitive article on Performance Tuning SSIS uses Sort and Aggregate as examples of Blocking Transformations. I’ve just shown you that Aggregate operations used by the Query Optimizer are not always blocking, but that the SSIS Aggregate component is an example of a blocking transformation. But is it always the case? After all, there are plenty of SSIS Performance Tuning talks out there that describe the value of sorted data in Data Flow Tasks, describing the IsSorted property that can be set through the Advanced Editor of your Source component. And so I set about testing the Aggregate transformation in SSIS, to prove for sure whether providing Sorted data would let the Aggregate transform behave like a Stream Aggregate. (Of course, I knew the answer already, but it helps to be able to demonstrate these things). A query that will produce a million rows in order was in order. Let me rephrase. I used a query which produced the numbers from 1 to 1000000, in a single field, ordered. The IsSorted flag was set on the source output, with the only column as SortKey 1. Performing an Aggregate function over this (counting the number of rows per distinct number) should produce an additional column with 1 in it. If this were being done in T-SQL, the ordered data would allow a Stream Aggregate to be used. In fact, if the Query Optimizer saw that the field had a Unique Index on it, it would be able to skip the Aggregate function completely, and just insert the value 1. This is a shortcut I wouldn’t be expecting from SSIS, but certainly the Stream behaviour would be nice. Unfortunately, it’s not the case. As you can see from the screenshots above, the data is pouring into the Aggregate function, and not being released until all million rows have been seen. It’s not doing a Stream Aggregate at all. This is expected behaviour. (I put that in bold, because I want you to realise this.) An SSIS transformation is a piece of code that runs. It’s a physical operation. When you write T-SQL and ask for an aggregation to be done, it’s a logical operation. The physical operation is either a Stream Aggregate or a Hash Match. In SSIS, you’re telling the system that you want a generic Aggregation, that will have to work with whatever data is passed in. I’m not saying that it wouldn’t be possible to make a sometimes-blocking aggregation component in SSIS. A Custom Component could be created which could detect whether the SortKeys columns of the input matched the Grouping columns of the Aggregation, and either call the blocking code or the non-blocking code as appropriate. One day I’ll make one of those, and publish it on my blog. I’ve done it before with a Script Component, but as Script components are single-use, I was able to handle the data knowing everything about my data flow already. As per my previous post – there are a lot of aspects in which tuning SSIS and tuning execution plans use similar concepts. In both situations, it really helps to have a feel for what’s going on behind the scenes. Considering whether an operation is blocking or not is extremely relevant to performance, and that it’s not always obvious from the surface. In a future post, I’ll show the impact of blocking v non-blocking and synchronous v asynchronous components in SSIS, using some of LobsterPot’s Script Components and Custom Components as examples. When I get that sorted, I’ll make a Stream Aggregate component available for download.

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• SQL SERVER – Core Concepts – Elasticity, Scalability and ACID Properties – Exploring NuoDB an Elastically Scalable Database System

  - by pinaldave

  I have been recently exploring Elasticity and Scalability attributes of databases. You can see that in my earlier blog posts about NuoDB where I wanted to look at Elasticity and Scalability concepts. The concepts are very interesting, and intriguing as well. I have discussed these concepts with my friend Joyti M and together we have come up with this interesting read. The goal of this article is to answer following simple questions What is Elasticity? What is Scalability? How ACID properties vary from NOSQL Concepts? What are the prevailing problems in the current database system architectures? Why is NuoDB  an innovative and welcome change in database paradigm? Elasticity This word’s original form is used in many different ways and honestly it does do a decent job in holding things together over the years as a person grows and contracts. Within the tech world, and specifically related to software systems (database, application servers), it has come to mean a few things - allow stretching of resources without reaching the breaking point (on demand). What are resources in this context? Resources are the usual suspects – RAM/CPU/IO/Bandwidth in the form of a container (a process or bunch of processes combined as modules). When it is about increasing resources the simplest idea which comes to mind is the addition of another container. Another container means adding a brand new physical node. When it is about adding a new node there are two questions which comes to mind. 1) Can we add another node to our software system? 2) If yes, does adding new node cause downtime for the system? Let us assume we have added new node, let us see what the new needs of the system are when a new node is added. Balancing incoming requests to multiple nodes Synchronization of a shared state across multiple nodes Identification of “downstate” and resolution action to bring it to “upstate” Well, adding a new node has its advantages as well. Here are few of the positive points Throughput can increase nearly horizontally across the node throughout the system Response times of application will increase as in-between layer interactions will be improved Now, Let us put the above concepts in the perspective of a Database. When we mention the term “running out of resources” or “application is bound to resources” the resources can be CPU, Memory or Bandwidth. The regular approach to “gain scalability” in the database is to look around for bottlenecks and increase the bottlenecked resource. When we have memory as a bottleneck we look at the data buffers, locks, query plans or indexes. After a point even this is not enough as there needs to be an efficient way of managing such large workload on a “single machine” across memory and CPU bound (right kind of scheduling)  workload. We next move on to either read/write separation of the workload or functionality-based sharing so that we still have control of the individual. But this requires lots of planning and change in client systems in terms of knowing where to go/update/read and for reporting applications to “aggregate the data” in an intelligent way. What we ideally need is an intelligent layer which allows us to do these things without us getting into managing, monitoring and distributing the workload. Scalability In the context of database/applications, scalability means three main things Ability to handle normal loads without pressure E.g. X users at the Y utilization of resources (CPU, Memory, Bandwidth) on the Z kind of hardware (4 processor, 32 GB machine with 15000 RPM SATA drives and 1 GHz Network switch) with T throughput Ability to scale up to expected peak load which is greater than normal load with acceptable response times Ability to provide acceptable response times across the system E.g. Response time in S milliseconds (or agreed upon unit of measure) – 90% of the time The Issue – Need of Scale In normal cases one can plan for the load testing to test out normal, peak, and stress scenarios to ensure specific hardware meets the needs. With help from Hardware and Software partners and best practices, bottlenecks can be identified and requisite resources added to the system. Unfortunately this vertical scale is expensive and difficult to achieve and most of the operational people need the ability to scale horizontally. This helps in getting better throughput as there are physical limits in terms of adding resources (Memory, CPU, Bandwidth and Storage) indefinitely. Today we have different options to achieve scalability: Read & Write Separation The idea here is to do actual writes to one store and configure slaves receiving the latest data with acceptable delays. Slaves can be used for balancing out reads. We can also explore functional separation or sharing as well. We can separate data operations by a specific identifier (e.g. region, year, month) and consolidate it for reporting purposes. For functional separation the major disadvantage is when schema changes or workload pattern changes. As the requirement grows one still needs to deal with scale need in manual ways by providing an abstraction in the middle tier code. Using NOSQL solutions The idea is to flatten out the structures in general to keep all values which are retrieved together at the same store and provide flexible schema. The issue with the stores is that they are compromising on mostly consistency (no ACID guarantees) and one has to use NON-SQL dialect to work with the store. The other major issue is about education with NOSQL solutions. Would one really want to make these compromises on the ability to connect and retrieve in simple SQL manner and learn other skill sets? Or for that matter give up on ACID guarantee and start dealing with consistency issues? Hybrid Deployment – Mac, Linux, Cloud, and Windows One of the challenges today that we see across On-premise vs Cloud infrastructure is a difference in abilities. Take for example SQL Azure – it is wonderful in its concepts of throttling (as it is shared deployment) of resources and ability to scale using federation. However, the same abilities are not available on premise. This is not a mistake, mind you – but a compromise of the sweet spot of workloads, customer requirements and operational SLAs which can be supported by the team. In today’s world it is imperative that databases are available across operating systems – which are a commodity and used by developers of all hues. An Ideal Database Ability List A system which allows a linear scale of the system (increase in throughput with reasonable response time) with the addition of resources A system which does not compromise on the ACID guarantees and require developers to learn new paradigms A system which does not force fit a new way interacting with database by learning Non-SQL dialect A system which does not force fit its mechanisms for providing availability across its various modules. Well NuoDB is the first database which has all of the above abilities and much more. In future articles I will cover my hands-on experience with it. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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• Running Solaris 11 as a control domain on a T2000

  - by jsavit

  There is increased adoption of Oracle Solaris 11, and many customers are deploying it on systems that previously ran Solaris 10. That includes older T1-processor based systems like T1000 and T2000. Even though they are old (from 2005) and don't have the performance of current SPARC servers, they are still functional, stable servers that customers continue to operate. One reason to install Solaris 11 on them is that older machines are attractive for testing OS upgrades before updating current, production systems. Normally this does not present a challenge, because Solaris 11 runs on any T-series or M-series SPARC server. One scenario adds a complication: running Solaris 11 in a control domain on a T1000 or T2000 hosting logical domains. Solaris 11 pre-installed Oracle VM Server for SPARC incompatible with T1 Unlike Solaris 10, Solaris 11 comes with Oracle VM Server for SPARC preinstalled. The ldomsmanager package contains the logical domains manager for Oracle VM Server for SPARC 2.2, which requires a SPARC T2, T2+, T3, or T4 server. It does not work with T1-processor systems, which are only supported by LDoms Manager 1.2 and earlier. The following screenshot shows what happens (bold font) if you try to use Oracle VM Server for SPARC 2.x commands in a Solaris 11 control domain. The commands were issued in a control domain on a T2000 that previously ran Solaris 10. We also display the version of the logical domains manager installed in Solaris 11: root@t2000 psrinfo -vp The physical processor has 4 virtual processors (0-3) UltraSPARC-T1 (chipid 0, clock 1200 MHz) # prtconf|grep T SUNW,Sun-Fire-T200 # ldm -V Failed to connect to logical domain manager: Connection refused # pkg info ldomsmanager Name: system/ldoms/ldomsmanager Summary: Logical Domains Manager Description: LDoms Manager - Virtualization for SPARC T-Series Category: System/Virtualization State: Installed Publisher: solaris Version: 2.2.0.0 Build Release: 5.11 Branch: 0.175.0.8.0.3.0 Packaging Date: May 25, 2012 10:20:48 PM Size: 2.86 MB FMRI: pkg://solaris/system/ldoms/[email protected],5.11-0.175.0.8.0.3.0:20120525T222048Z The 2.2 version of the logical domains manager will have to be removed, and 1.2 installed, in order to use this as a control domain. Preparing to change - create a new boot environment Before doing anything else, lets create a new boot environment: # beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- solaris NR / 2.14G static 2012-09-25 10:32 # beadm create solaris-1 # beadm activate solaris-1 # beadm list BE Active Mountpoint Space Policy Created -- ------ ---------- ----- ------ ------- solaris N / 4.82M static 2012-09-25 10:32 solaris-1 R - 2.14G static 2012-09-29 11:40 # init 0 Normally an init 6 to reboot would have been sufficient, but in the next step I reset the system anyway in order to put the system in factory default mode for a "clean" domain configuration. Preparing to change - reset to factory default There was a leftover domain configuration on the T2000, so I reset it to the factory install state. Since the ldm command is't working yet, it can't be done from the control domain, so I did it by logging onto to the service processor: $ ssh -X admin@t2000-sc Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved. Oracle Advanced Lights Out Manager CMT v1.7.9 Please login: admin Please Enter password: ******** sc> showhost Sun-Fire-T2000 System Firmware 6.7.10 2010/07/14 16:35 Host flash versions: OBP 4.30.4.b 2010/07/09 13:48 Hypervisor 1.7.3.c 2010/07/09 15:14 POST 4.30.4.b 2010/07/09 14:24 sc> bootmode config="factory-default" sc> poweroff Are you sure you want to power off the system [y/n]? y SC Alert: SC Request to Power Off Host. SC Alert: Host system has shut down. sc> poweron SC Alert: Host System has Reset At this point I rebooted into the new Solaris 11 boot environment, and Solaris commands showed it was running on the factory default configuration of a single domain owning all 32 CPUs and 32GB of RAM (that's what it looked like in 2005.) # psrinfo -vp The physical processor has 8 cores and 32 virtual processors (0-31) The core has 4 virtual processors (0-3) The core has 4 virtual processors (4-7) The core has 4 virtual processors (8-11) The core has 4 virtual processors (12-15) The core has 4 virtual processors (16-19) The core has 4 virtual processors (20-23) The core has 4 virtual processors (24-27) The core has 4 virtual processors (28-31) UltraSPARC-T1 (chipid 0, clock 1200 MHz) # prtconf|grep Mem Memory size: 32640 Megabytes Note that the older processor has 4 virtual CPUs per core, while current processors have 8 per core. Remove ldomsmanager 2.2 and install the 1.2 version The Solaris 11 pkg command is now used to remove the 2.2 version that shipped with Solaris 11: # pkg uninstall ldomsmanager Packages to remove: 1 Create boot environment: No Create backup boot environment: No Services to change: 2 PHASE ACTIONS Removal Phase 130/130 PHASE ITEMS Package State Update Phase 1/1 Package Cache Update Phase 1/1 Image State Update Phase 2/2 Finally, LDoms 1.2 installed via its install script, the same way it was done years ago: # unzip LDoms-1_2-Integration-10.zip # cd LDoms-1_2-Integration-10/Install/ # ./install-ldm Welcome to the LDoms installer. You are about to install the Logical Domains Manager package that will enable you to create, destroy and control other domains on your system. Given the capabilities of the LDoms domain manager, you can now change the security configuration of this Solaris instance using the Solaris Security Toolkit. ... ... normal install messages omitted ... The Solaris Security Toolkit applies to Solaris 10, and cannot be used in Solaris 11 (in which several things hardened by the Toolkit are already hardened by default), so answer b in the choice below: You are about to install the Logical Domains Manager package that will enable you to create, destroy and control other domains on your system. Given the capabilities of the LDoms domain manager, you can now change the security configuration of this Solaris instance using the Solaris Security Toolkit. Select a security profile from this list: a) Hardened Solaris configuration for LDoms (recommended) b) Standard Solaris configuration c) Your custom-defined Solaris security configuration profile Enter a, b, or c [a]: b ... other install messages omitted for brevity... After install I ensure that the necessary services are enabled, and verify the version of the installed LDoms Manager: # svcs ldmd STATE STIME FMRI online 22:00:36 svc:/ldoms/ldmd:default # svcs vntsd STATE STIME FMRI disabled Aug_19 svc:/ldoms/vntsd:default # ldm -V Logical Domain Manager (v 1.2-debug) Hypervisor control protocol v 1.3 Using Hypervisor MD v 1.1 System PROM: Hypervisor v. 1.7.3. @(#)Hypervisor 1.7.3.c 2010/07/09 15:14\015 OpenBoot v. 4.30.4. @(#)OBP 4.30.4.b 2010/07/09 13:48 Set up control domain and domain services At this point we have a functioning LDoms 1.2 environment that can be configured in the usual fashion. One difference is that LDoms 1.2 behavior had 'delayed configuration mode (as expected) during initial configuration before rebooting the control domain. Another minor difference with a Solaris 11 control domain is that you define virtual switches using the 'vanity name' of the network interface, rather than the hardware driver name as in Solaris 10. # ldm list ------------------------------------------------------------------------------ Notice: the LDom Manager is running in configuration mode. Configuration and resource information is displayed for the configuration under construction; not the current active configuration. The configuration being constructed will only take effect after it is downloaded to the system controller and the host is reset. ------------------------------------------------------------------------------ NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-c-- SP 32 32640M 3.2% 4d 2h 50m # ldm add-vdiskserver primary-vds0 primary # ldm add-vconscon port-range=5000-5100 primary-vcc0 primary # ldm add-vswitch net-dev=net0 primary-vsw0 primary # ldm set-mau 2 primary # ldm set-vcpu 8 primary # ldm set-memory 4g primary # ldm add-config initial # ldm list-spconfig factory-default initial [current] That's it, really. After reboot, we are ready to install guest domains. Summary - new wine in old bottles This example shows that (new) Solaris 11 can be installed on (old) T2000 servers and used as a control domain. The main activity is to remove the preinstalled Oracle VM Server for 2.2 and install Logical Domains 1.2 - the last version of LDoms to support T1-processor systems. I tested Solaris 10 and Solaris 11 guest domains running on this server and they worked without any surprises. This is a viable way to get further into Solaris 11 adoption, even on older T-series equipment.

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• Hard drive mounted at / , duplicate mounted hard drive after using MountManager

  - by HellHarvest

  possible duplicate post I'm running 12.04 64bit. My system is a dual boot for both Ubuntu and Windows7. Both operating systems are sharing the drive named "Elements". My volume named "Elements" is a 1TB SATA NTFS hard drive that shows up twice in the side bar in nautilus. One of the icons is functional and even has the convenient "eject" icon next to it. Below is a picture of the left menu in Nautilus, with System Monitor-File Systems tab open on top of it. Can someone advise me about how to get rid of this extra icon? I think the problem is much more deep-rooted than just a GUI glitch on Nautilus' part. The other icon does nothing but spit out the following error when I click on it (image below). This only happened AFTER I tried using Mount Manager to automate mounting the drive at start up. I've already uninstalled Mount Manager, and restarted, but the problem didn't go away. The hard drive does mount automatically now, so I guess that's cool. But now, every time I boot up now and open Nautilus, BOTH of these icons appear, one of which is fictitious and useless. According to the image above and the outputs of several other commands, it appears to be mounted at / In which case, no matter where I am in Nautilus when I try to click on that icon, of course it will tell me that that drive is in use by another program... Nautilus. I'm afraid of trying to unmount this hard drive (sdb6) because of where it appears to be mounted. I'm kind of a noob, and I have this gut feeling that tells me trying to unmount a drive at / will destroy my entire file system. This fear was further strengthened by the output of "$ fsck" at the very bottom of this post. Error immediately below when that 2nd "Elements" hard drive is clicked in Nautilus: Unable to mount Elements Mount is denied because the NTFS volume is already exclusively opened. The volume may be already mounted, or another software may use it which could be identified for example by the help of the 'fuser' command. It's odd to me that that error message above claims that it's an NTFS volume when everything else tell me that it's an ext4 volume. The actual hard drive "Elements" is in fact an NTFS volume. Here's the output of a few commands and configuration files that may be of interest: $ fuser -a / /: 2120r 2159rc 2160rc 2172r 2178rc 2180rc 2188r 2191rc 2200rc 2203rc 2205rc 2206r 2211r 2212r 2214r 2220r 2228r 2234rc 2246rc 2249rc 2254rc 2260rc 2261r 2262r 2277rc 2287rc 2291rc 2311rc 2313rc 2332rc 2334rc 2339rc 2343rc 2344rc 2352rc 2372rc 2389rc 2422r 2490r 2496rc 2501rc 2566r 2573rc 2581rc 2589rc 2592r 2603r 2611rc 2613rc 2615rc 2678rc 2927r 2981r 3104rc 4156rc 4196rc 4206rc 4213rc 4240rc 4297rc 5032rc 7609r 7613r 7648r 9593rc 18829r 18833r 19776r $ sudo df -h Filesystem Size Used Avail Use% Mounted on /dev/sdb6 496G 366G 106G 78% / udev 2.0G 4.0K 2.0G 1% /dev tmpfs 791M 1.5M 790M 1% /run none 5.0M 0 5.0M 0% /run/lock none 2.0G 672K 2.0G 1% /run/shm /dev/sda1 932G 312G 620G 34% /media/Elements /home/solderblob/.Private 496G 366G 106G 78% /home/solderblob /dev/sdb2 188G 100G 88G 54% /media/A2B24EACB24E852F /dev/sdb1 100M 25M 76M 25% /media/System Reserved $ sudo fdisk -l Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00093cab Device Boot Start End Blocks Id System /dev/sda1 2048 1953519615 976758784 7 HPFS/NTFS/exFAT Disk /dev/sdb: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000e8d9b Device Boot Start End Blocks Id System /dev/sdb1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sdb2 206848 392378768 196085960+ 7 HPFS/NTFS/exFAT /dev/sdb3 392380414 1465147391 536383489 5 Extended /dev/sdb5 1456762880 1465147391 4192256 82 Linux swap / Solaris /dev/sdb6 392380416 1448374271 527996928 83 Linux /dev/sdb7 1448376320 1456758783 4191232 82 Linux swap / Solaris Partition table entries are not in disk order $ cat /etc/fstab # <file system> <mount point> <type> <options> <dump> <pass> UUID=77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e / ext4 defaults 0 1 UUID=F6549CC4549C88CF /media/Elements ntfs-3g users 0 0 $ sudo blkid /dev/sda1: LABEL="Elements" UUID="F6549CC4549C88CF" TYPE="ntfs" /dev/sdb1: LABEL="System Reserved" UUID="5CDE130FDE12E156" TYPE="ntfs" /dev/sdb2: UUID="A2B24EACB24E852F" TYPE="ntfs" /dev/sdb6: UUID="77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e" TYPE="ext4" $ sudo blkid -c /dev/null (appears to be exactly the same as above) /dev/sda1: LABEL="Elements" UUID="F6549CC4549C88CF" TYPE="ntfs" /dev/sdb1: LABEL="System Reserved" UUID="5CDE130FDE12E156" TYPE="ntfs" /dev/sdb2: UUID="A2B24EACB24E852F" TYPE="ntfs" /dev/sdb6: UUID="77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e" TYPE="ext4" $ mount /dev/sdb6 on / type ext4 (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) /dev/sda1 on /media/Elements type fuseblk (rw,noexec,nosuid,nodev,allow_other,blksize=4096) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) /home/solderblob/.Private on /home/solderblob type ecryptfs (ecryptfs_check_dev_ruid,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs,ecryptfs_sig=76a47b0175afa48d,ecryptfs_fnek_sig=391b2d8b155215f7) gvfs-fuse-daemon on /home/solderblob/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=solderblob) /dev/sdb2 on /media/A2B24EACB24E852F type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) /dev/sdb1 on /media/System Reserved type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096) $ ls -a . A2B24EACB24E852F Ubuntu 12.04.1 LTS amd64 .. Elements System Reserved $ cat /proc/mounts rootfs / rootfs rw 0 0 sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0 proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0 udev /dev devtmpfs rw,relatime,size=2013000k,nr_inodes=503250,mode=755 0 0 devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0 tmpfs /run tmpfs rw,nosuid,relatime,size=809872k,mode=755 0 0 /dev/disk/by-uuid/77039a2a-83d4-47a1-8a8c-a2ec4e4dfd0e / ext4 rw,relatime,user_xattr,acl,barrier=1,data=ordered 0 0 none /sys/fs/fuse/connections fusectl rw,relatime 0 0 none /sys/kernel/debug debugfs rw,relatime 0 0 none /sys/kernel/security securityfs rw,relatime 0 0 none /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0 none /run/shm tmpfs rw,nosuid,nodev,relatime 0 0 /dev/sda1 /media/Elements fuseblk rw,nosuid,nodev,noexec,relatime,user_id=0,group_id=0,allow_other,blksize=4096 0 0 binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc rw,nosuid,nodev,noexec,relatime 0 0 /home/solderblob/.Private /home/solderblob ecryptfs rw,relatime,ecryptfs_fnek_sig=391b2d8b155215f7,ecryptfs_sig=76a47b0175afa48d,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs 0 0 gvfs-fuse-daemon /home/solderblob/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0 /dev/sdb2 /media/A2B24EACB24E852F fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0 /dev/sdb1 /media/System\040Reserved fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096 0 0 gvfs-fuse-daemon /root/.gvfs fuse.gvfs-fuse-daemon rw,nosuid,nodev,relatime,user_id=0,group_id=0 0 0 $ fsck fsck from util-linux 2.20.1 e2fsck 1.42 (29-Nov-2011) /dev/sdb6 is mounted. WARNING!!! The filesystem is mounted. If you continue you ***WILL*** cause ***SEVERE*** filesystem damage. Do you really want to continue<n>? no check aborted.

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• No root file system is defined error after installation

  - by LearnCode

  I installed ubuntu through Wubi and once i rebooted I get no root file system defined error. here's the output of the boot_info_script.Could anyone point me out where the error is. Boot Info Script 0.60 from 17 May 2011 ============================= Boot Info Summary: =============================== => Windows is installed in the MBR of /dev/sda. => Windows is installed in the MBR of /dev/sdb. sda1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe /ntldr /ntdetect.com /wubildr /ubuntu/winboot/wubildr /wubildr.mbr /ubuntu/winboot/wubildr.mbr /ubuntu/disks/root.disk /ubuntu/disks/swap.disk sda1/Wubi: _____________________________________________________________________ File system: Boot sector type: Unknown Boot sector info: Mounting failed: mount: unknown filesystem type '' sda2: __________________________________________________________________________ File system: vfat Boot sector type: Unknown Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /boot.ini /ntldr /NTDETECT.COM sdb1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 160.0 GB, 160041885696 bytes 240 heads, 63 sectors/track, 20673 cylinders, total 312581808 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 * 63 301,250,879 301,250,817 7 NTFS / exFAT / HPFS /dev/sda2 301,250,943 312,575,759 11,324,817 c W95 FAT32 (LBA) GUID Partition Table detected, but does not seem to be used. Partition Start Sector End Sector # of Sectors System /dev/sda1 323,465,741,313,502,988275,962,973,585-323,465,465,350,529,402 - /dev/sda2 242,728,591,638,290,720578,721,383,108,845,578335,992,791,470,554,859 - /dev/sda3 1,827,498,311,425,204,2562,091,935,274,843,009,907264,436,963,417,805,652 - /dev/sda4 579,711,218,081,401,3572,006,665,459,744,645,1521,426,954,241,663,243,796 - /dev/sda11 270,286,346,402,038,1183,786,543,326,404,525,9543,516,256,980,002,487,837 - /dev/sda12 4,179,681,002,230,769,6684,179,389,374,010,033,387-291,628,220,736,280 - /dev/sda13 232,556,480,979,456,1311,160,152,593,793,119,235927,596,112,813,663,105 - /dev/sda14 98,342,784,050,266,9183,691,264,578,843,725,1953,592,921,794,793,458,278 - /dev/sda15 2,307,845,219,957,882,4961,850,841,032,955,276,350-457,004,187,002,606,145 - /dev/sda16 512,592,046,878,946,497368,458,231,024,779,444-144,133,815,854,167,052 - /dev/sda17 2,504,135,232,870,384,3923,665,087,872,719,320,8291,160,952,639,848,936,438 - /dev/sda18 3,783,181,605,270,691,304122,034,509,624,708,942-3,661,147,095,645,982,361 - /dev/sda19 3,519,661,520,275,829,5122,376,243,094,723,723,587-1,143,418,425,552,105,924 - /dev/sda20 3,867,920,076,859,0744,494,691,111,933,625,1044,490,823,191,856,766,031 - /dev/sda21 1,500,144,061,909,253,7612,511,182,033,846,676,3401,011,037,971,937,422,580 - /dev/sda22 13,035,625,499,900,0062,360,168,613,941,394,9472,347,132,988,441,494,942 - /dev/sda23 4,228,978,682,068,599,48813,159,423,631,648,263-4,215,819,258,436,951,224 - /dev/sda24 3,695,955,742,872,046,9084,561,928,726,501,845,776865,972,983,629,798,869 - /dev/sda25 1,297,460,286,683,948,0461,444,350,486,339,417,957146,890,199,655,469,912 - /dev/sda26 1,228,858,248,533,131,831 0-1,228,858,248,533,131,830 - /dev/sda121 3,189,184,846,146,487,1461,849,820,258,006,914,852-1,339,364,588,139,572,293 - /dev/sda122 1,226,215,547,991,800,578389,781,518,734,546,300-836,434,029,257,254,277 - /dev/sda123 3,851,660,168,574,583,4654,046,215,657,583,031,556194,555,489,008,448,092 - /dev/sda124 1,197,460,980,174,153,341699,103,965,005,093,246-498,357,015,169,060,094 - Drive: sdb _____________________________________________________________________ Disk /dev/sdb: 750.2 GB, 750153367552 bytes 255 heads, 63 sectors/track, 91200 cylinders, total 1465143296 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdb1 2,048 1,465,143,295 1,465,141,248 7 NTFS / exFAT / HPFS "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/loop0 iso9660 Ubuntu 11.04 amd64 /dev/loop1 squashfs /dev/sda1 E814B55B14B52E06 ntfs /dev/sda2 01CD-023B vfat HP_RECOVERY /dev/sdb1 7836F22A36F1E8D0 ntfs Elements ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /cdrom iso9660 (ro,noatime) /dev/loop1 /rofs squashfs (ro,noatime) /dev/sdb1 /mnt fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) ================================ sda2/boot.ini: ================================ -------------------------------------------------------------------------------- [boot loader] timeout=0 default=C:\CMDCONS\BOOTSECT.DAT [operating systems] multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /fastdetect C:\CMDCONS\BOOTSECT.DAT="Microsoft Windows Recovery Console" /cmdcons -------------------------------------------------------------------------------- ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown GPT Partiton Type c104043000e9b9040dff24b580010100 Unknown GPT Partiton Type 46313020746f20737461727420746865 Unknown GPT Partiton Type 65727920706172746974696f6e207761 Unknown GPT Partiton Type 727920706172746974696f6e0d0a0000 Unknown GPT Partiton Type 000f84e5f7668b162404e82804744066 Unknown GPT Partiton Type ce01e8dc038bfe66391624047505e8d9 Unknown GPT Partiton Type 0345086603f0e881030bd2740333d240 Unknown GPT Partiton Type bece01e8db0287fec645041266895508 Unknown GPT Partiton Type 01f60634010175078b363b01e854f5e8 Unknown GPT Partiton Type 313825740ffec03865107408fec03824 Unknown GPT Partiton Type 02f60634014074088bfdbece01e85101 Unknown GPT Partiton Type 263401f9e894f30f858ef4e8e201e8ec Unknown GPT Partiton Type f7e960f35245434f5645525966606633 Unknown GPT Partiton Type 660faf1e00106603dac3668b0e001066 Unknown GPT Partiton Type 8bfd386d04740583c710e2f6c36660c6 Unknown GPT Partiton Type 04ebf132c0b91000f3aac3bf0c04ebf3 Unknown GPT Partiton Type 02662bc1660fb71e0e02662bc366031e Unknown GPT Partiton Type f4b40ebb0700b901003c08751381ff25 Unknown GPT Partiton Type 534f465448494e4b90653f62011b0100 Unknown GPT Partiton Type 0b050900027777772e68702e636f6d00 Unknown GPT Partiton Type d441a0f5030003000ecb744a08bb3746 Unknown GPT Partiton Type f8579a116b4a7aa931cde97a4b9b5c09 Unknown GPT Partiton Type 7229990415b77c0a1970e7e824237a3a Unknown GPT Partiton Type afb6e34d6b4bd8c7c0eada19a9786cc3 Unknown BootLoader on sda1/Wubi 00000000 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000| * 00000200 Unknown BootLoader on sda2 00000000 e9 a7 00 52 45 43 4f 56 45 52 59 00 02 08 20 00 |...RECOVERY... .| 00000010 02 00 00 00 00 f8 00 00 3f 00 f0 00 7f b9 f4 11 |........?.......| 00000020 8c cd ac 00 1e 2b 00 00 00 00 00 00 02 00 00 00 |.....+..........| 00000030 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000040 80 00 29 3b 02 cd 01 20 20 20 20 20 20 20 20 20 |..);... | 00000050 20 20 46 41 54 33 32 20 20 20 8b d0 c1 e2 02 80 | FAT32 ......| 00000060 e6 01 66 c1 e8 07 66 3b 46 f8 74 2a 66 89 46 f8 |..f...f;F.t*f.F.| 00000070 66 03 46 f4 66 0f b6 5e 28 80 e3 0f 74 0f 3a 5e |f.F.f..^(...t.:^| 00000080 10 0f 83 90 00 66 0f af 5e 24 66 03 c3 bb e0 07 |.....f..^$f.....| 00000090 b9 01 00 e8 cf 00 8b da 66 8b 87 00 7e 66 25 ff |........f...~f%.| 000000a0 ff ff 0f 66 3d f8 ff ff 0f c3 33 c9 8e d9 8e c1 |...f=.....3.....| 000000b0 8e d1 66 bc f4 7b 00 00 bd 00 7c 66 0f b6 46 10 |..f..{....|f..F.| 000000c0 66 f7 66 24 66 0f b7 56 0e 66 03 56 1c 66 89 56 |f.f$f..V.f.V.f.V| 000000d0 f4 66 03 c2 66 89 46 fc 66 c7 46 f8 ff ff ff ff |.f..f.F.f.F.....| 000000e0 66 8b 46 2c 66 50 e8 af 00 bb 70 00 b9 01 00 e8 |f.F,fP....p.....| 000000f0 73 00 bf 00 07 b1 0b be a9 7d f3 a6 74 2a 03 f9 |s........}..t*..| 00000100 83 c7 15 81 ff 00 09 72 ec 66 40 4a 75 db 66 58 |[email protected]| 00000110 e8 47 ff 72 cf be b4 7d ac 84 c0 74 09 b4 0e bb |.G.r...}...t....| 00000120 07 00 cd 10 eb f2 cd 19 66 58 ff 75 09 ff 75 0f |........fX.u..u.| 00000130 66 58 bb 00 20 66 83 f8 02 72 da 66 3d f8 ff ff |fX.. f...r.f=...| 00000140 0f 73 d2 66 50 e8 50 00 0f b6 4e 0d e8 16 00 c1 |.s.fP.P...N.....| 00000150 e1 05 03 d9 66 58 53 e8 00 ff 5b 72 d8 8a 56 40 |....fXS...[r..V@| 00000160 ea 00 00 00 20 66 60 66 6a 00 66 50 53 6a 00 66 |.... f`fj.fPSj.f| 00000170 68 10 00 01 00 8b f4 b8 00 42 8a 56 40 cd 13 be |h........B.V@...| 00000180 c7 7d 72 94 67 83 44 24 06 20 66 67 ff 44 24 08 |.}r.g.D$. fg.D$.| 00000190 e2 e3 83 c4 10 66 61 c3 66 48 66 48 66 0f b6 56 |.....fa.fHfHf..V| 000001a0 0d 66 f7 e2 66 03 46 fc c3 4e 54 4c 44 52 20 20 |.f..f.F..NTLDR | 000001b0 20 20 20 20 0d 0a 4e 6f 20 53 79 73 74 65 6d 20 | ..No System | 000001c0 44 69 73 6b 20 6f 72 0d 0a 44 69 73 6b 20 49 2f |Disk or..Disk I/| 000001d0 4f 20 65 72 72 6f 72 0d 0a 50 72 65 73 73 20 61 |O error..Press a| 000001e0 20 6b 65 79 20 74 6f 20 72 65 73 74 61 72 74 0d | key to restart.| 000001f0 0a 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 =============================== StdErr Messages: =============================== umount: /isodevice: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1))

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• Oracle Flashback Technologies - Overview

  - by Sridhar_R-Oracle

  Oracle Flashback Technologies - IntroductionIn his May 29th 2014 blog, my colleague Joe Meeks introduced Oracle Maximum Availability Architecture (MAA) and discussed both planned and unplanned outages. Let’s take a closer look at unplanned outages. These can be caused by physical failures (e.g., server, storage, network, file deletion, physical corruption, site failures) or by logical failures – cases where all components and files are physically available, but data is incorrect or corrupt. These logical failures are usually caused by human errors or application logic errors. This blog series focuses on these logical errors – what causes them and how to address and recover from them using Oracle Database Flashback. In this introductory blog post, I’ll provide an overview of the Oracle Database Flashback technologies and will discuss the features in detail in future blog posts. Let’s get started. We are all human beings (unless a machine is reading this), and making mistakes is a part of what we do…often what we do best!  We “fat finger”, we spill drinks on keyboards, unplug the wrong cables, etc.  In addition, many of us, in our lives as DBAs or developers, must have observed, caused, or corrected one or more of the following unpleasant events: Accidentally updated a table with wrong values !! Performed a batch update that went wrong - due to logical errors in the code !! Dropped a table !! How do DBAs typically recover from these types of errors? First, data needs to be restored and recovered to the point-in-time when the error occurred (incomplete or point-in-time recovery).  Moreover, depending on the type of fault, it’s possible that some services – or even the entire database – would have to be taken down during the recovery process.Apart from error conditions, there are other questions that need to be addressed as part of the investigation. For example, what did the data look like in the morning, prior to the error? What were the various changes to the row(s) between two timestamps? Who performed the transaction and how can it be reversed?  Oracle Database includes built-in Flashback technologies, with features that address these challenges and questions, and enable you to perform faster, easier, and convenient recovery from logical corruptions. HistoryFlashback Query, the first Flashback Technology, was introduced in Oracle 9i. It provides a simple, powerful and completely non-disruptive mechanism for data verification and recovery from logical errors, and enables users to view the state of data at a previous point in time.Flashback Technologies were further enhanced in Oracle 10g, to provide fast, easy recovery at the database, table, row, and even at a transaction level.Oracle Database 11g introduced an innovative method to manage and query long-term historical data with Flashback Data Archive. The 11g release also introduced Flashback Transaction, which provides an easy, one-step operation to back out a transaction. Oracle Database versions 11.2.0.2 and beyond further enhanced the performance of these features. Note that all the features listed here work without requiring any kind of restore operation.In addition, Flashback features are fully supported with the new multi-tenant capabilities introduced with Oracle Database 12c, Flashback Features Oracle Flashback Database enables point-in-time-recovery of the entire database without requiring a traditional restore and recovery operation. It rewinds the entire database to a specified point in time in the past by undoing all the changes that were made since that time.Oracle Flashback Table enables an entire table or a set of tables to be recovered to a point in time in the past.Oracle Flashback Drop enables accidentally dropped tables and all dependent objects to be restored.Oracle Flashback Query enables data to be viewed at a point-in-time in the past. This feature can be used to view and reconstruct data that was lost due to unintentional change(s) or deletion(s). This feature can also be used to build self-service error correction into applications, empowering end-users to undo and correct their errors.Oracle Flashback Version Query offers the ability to query the historical changes to data between two points in time or system change numbers (SCN) Oracle Flashback Transaction Query enables changes to be examined at the transaction level. This capability can be used to diagnose problems, perform analysis, audit transactions, and even revert the transaction by undoing SQLOracle Flashback Transaction is a procedure used to back-out a transaction and its dependent transactions.Flashback technologies eliminate the need for a traditional restore and recovery process to fix logical corruptions or make enquiries. Using these technologies, you can recover from the error in the same amount of time it took to generate the error. All the Flashback features can be accessed either via SQL command line (or) via Enterprise Manager.  Most of the Flashback technologies depend on the available UNDO to retrieve older data. The following table describes the various Flashback technologies: their purpose, dependencies and situations where each individual technology can be used.   Example Syntax Error investigation related:The purpose is to investigate what went wrong and what the values were at certain points in timeFlashback Queries  ( select .. as of SCN | Timestamp )   - Helps to see the value of a row/set of rows at a point in timeFlashback Version Queries  ( select .. versions between SCN | Timestamp and SCN | Timestamp)  - Helps determine how the value evolved between certain SCNs or between timestamps Flashback Transaction Queries (select .. XID=)   - Helps to understand how the transaction caused the changes.Error correction related:The purpose is to fix the error and correct the problems,Flashback Table  (flashback table .. to SCN | Timestamp)  - To rewind the table to a particular timestamp or SCN to reverse unwanted updates Flashback Drop (flashback table ..  to before drop )  - To undrop or undelete a table Flashback Database (flashback database to SCN  | Restore Point )  - This is the rewind button for Oracle databases. You can revert the entire database to a particular point in time. It is a fast way to perform a PITR (point-in-time recovery). Flashback Transaction (DBMS_FLASHBACK.TRANSACTION_BACKOUT(XID..))  - To reverse a transaction and its related transactions Advanced use cases Flashback technology is integrated into Oracle Recovery Manager (RMAN) and Oracle Data Guard. So, apart from the basic use cases mentioned above, the following use cases are addressed using Oracle Flashback. Block Media recovery by RMAN - to perform block level recovery Snapshot Standby - where the standby is temporarily converted to a read/write environment for testing, backup, or migration purposes Re-instate old primary in a Data Guard environment – this avoids the need to restore an old backup and perform a recovery to make it a new standby. Guaranteed Restore Points - to bring back the entire database to an older point-in-time in a guaranteed way. and so on..I hope this introductory overview helps you understand how Flashback features can be used to investigate and recover from logical errors.  As mentioned earlier, I will take a deeper-dive into to some of the critical Flashback features in my upcoming blogs and address common use cases.

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• SQL University: What and why of database refactoring

  - by Mladen Prajdic

  This is a post for a great idea called SQL University started by Jorge Segarra also famously known as SqlChicken on Twitter. It’s a collection of blog posts on different database related topics contributed by several smart people all over the world. So this week is mine and we’ll be talking about database testing and refactoring. In 3 posts we’ll cover: SQLU part 1 - What and why of database testing SQLU part 2 - What and why of database refactoring SQLU part 3 - Tools of the trade This is a second part of the series and in it we’ll take a look at what database refactoring is and why do it. Why refactor a database To know why refactor we first have to know what refactoring actually is. Code refactoring is a process where we change module internals in a way that does not change that module’s input/output behavior. For successful refactoring there is one crucial thing we absolutely must have: Tests. Automated unit tests are the only guarantee we have that we haven’t broken the input/output behavior before refactoring. If you haven’t go back ad read my post on the matter. Then start writing them. Next thing you need is a code module. Those are views, UDFs and stored procedures. By having direct table access we can kiss fast and sweet refactoring good bye. One more point to have a database abstraction layer. And no, ORM’s don’t fall into that category. But also know that refactoring is NOT adding new functionality to your code. Many have fallen into this trap. Don’t be one of them and resist the lure of the dark side. And it’s a strong lure. We developers in general love to add new stuff to our code, but hate fixing our own mistakes or changing existing code for no apparent reason. To be a good refactorer one needs discipline and focus. Now we know that refactoring is all about changing inner workings of existing code. This can be due to performance optimizations, changing internal code workflows or some other reason. This is a typical black box scenario to the outside world. If we upgrade the car engine it still has to drive on the road (preferably faster) and not fly (no matter how cool that would be). Also be aware that white box tests will break when we refactor. What to refactor in a database Refactoring databases doesn’t happen that often but when it does it can include a lot of stuff. Let us look at a few common cases. Adding or removing database schema objects Adding, removing or changing table columns in any way, adding constraints, keys, etc… All of these can be counted as internal changes not visible to the data consumer. But each of these carries a potential input/output behavior change. Dropping a column can result in views not working anymore or stored procedure logic crashing. Adding a unique constraint shows duplicated data that shouldn’t exist. Foreign keys break a truncate table command executed from an application that runs once a month. All these scenarios are very real and can happen. With the proper database abstraction layer fully covered with black box tests we can make sure something like that does not happen (hopefully at all). Changing physical structures Physical structures include heaps, indexes and partitions. We can pretty much add or remove those without changing the data returned by the database. But the performance can be affected. So here we use our performance tests. We do have them, right? Just by adding a single index we can achieve orders of magnitude performance improvement. Won’t that make users happy? But what if that index causes our write operations to crawl to a stop. again we have to test this. There are a lot of things to think about and have tests for. Without tests we can’t do successful refactoring! Fixing bad code We all have some bad code in our systems. We usually refer to that code as code smell as they violate good coding practices. Examples of such code smells are SQL injection, use of SELECT *, scalar UDFs or cursors, etc… Each of those is huge code smell and can result in major code changes. Take SELECT * from example. If we remove a column from a table the client using that SELECT * statement won’t have a clue about that until it runs. Then it will gracefully crash and burn. Not to mention the widely unknown SELECT * view refresh problem that Tomas LaRock (@SQLRockstar on Twitter) and Colin Stasiuk (@BenchmarkIT on Twitter) talk about in detail. Go read about it, it’s informative. Refactoring this includes replacing the * with column names and most likely change to application using the database. Breaking apart huge stored procedures Have you ever seen seen a stored procedure that was 2000 lines long? I have. It’s not pretty. It hurts the eyes and sucks the will to live the next 10 minutes. They are a maintenance nightmare and turn into things no one dares to touch. I’m willing to bet that 100% of time they don’t have a single test on them. Large stored procedures (and functions) are a clear sign that they contain business logic. General opinion on good database coding practices says that business logic has no business in the database. That’s the applications part. Refactoring such behemoths requires writing lots of edge case tests for the stored procedure input/output behavior and then start to refactor it. First we split the logic inside into smaller parts like new stored procedures and UDFs. Those then get called from the master stored procedure. Once we’ve successfully modularized the database code it’s best to transfer that logic into the applications consuming it. This only leaves the stored procedure with common data manipulation logic. Of course this isn’t always possible so having a plethora of performance and behavior unit tests is absolutely necessary to confirm we’ve actually improved the codebase in some way.   Refactoring is not a popular chore amongst developers or managers. The former don’t like fixing old code, the latter can’t see the financial benefit. Remember how we talked about being lousy at estimating future costs in the previous post? But there comes a time when it must be done. Hopefully I’ve given you some ideas how to get started. In the last post of the series we’ll take a look at the tools to use and an example of testing and refactoring.

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• When is a Seek not a Seek?

  - by Paul White

  The following script creates a single-column clustered table containing the integers from 1 to 1,000 inclusive. IF OBJECT_ID(N'tempdb..#Test', N'U') IS NOT NULL DROP TABLE #Test ; GO CREATE TABLE #Test ( id INTEGER PRIMARY KEY CLUSTERED ); ; INSERT #Test (id) SELECT V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 1000 ; Let’s say we need to find the rows with values from 100 to 170, excluding any values that divide exactly by 10.  One way to write that query would be: SELECT T.id FROM #Test AS T WHERE T.id IN ( 101,102,103,104,105,106,107,108,109, 111,112,113,114,115,116,117,118,119, 121,122,123,124,125,126,127,128,129, 131,132,133,134,135,136,137,138,139, 141,142,143,144,145,146,147,148,149, 151,152,153,154,155,156,157,158,159, 161,162,163,164,165,166,167,168,169 ) ; That query produces a pretty efficient-looking query plan: Knowing that the source column is defined as an INTEGER, we could also express the query this way: SELECT T.id FROM #Test AS T WHERE T.id >= 101 AND T.id <= 169 AND T.id % 10 > 0 ; We get a similar-looking plan: If you look closely, you might notice that the line connecting the two icons is a little thinner than before.  The first query is estimated to produce 61.9167 rows – very close to the 63 rows we know the query will return.  The second query presents a tougher challenge for SQL Server because it doesn’t know how to predict the selectivity of the modulo expression (T.id % 10 > 0).  Without that last line, the second query is estimated to produce 68.1667 rows – a slight overestimate.  Adding the opaque modulo expression results in SQL Server guessing at the selectivity.  As you may know, the selectivity guess for a greater-than operation is 30%, so the final estimate is 30% of 68.1667, which comes to 20.45 rows. The second difference is that the Clustered Index Seek is costed at 99% of the estimated total for the statement.  For some reason, the final SELECT operator is assigned a small cost of 0.0000484 units; I have absolutely no idea why this is so, or what it models.  Nevertheless, we can compare the total cost for both queries: the first one comes in at 0.0033501 units, and the second at 0.0034054.  The important point is that the second query is costed very slightly higher than the first, even though it is expected to produce many fewer rows (20.45 versus 61.9167). If you run the two queries, they produce exactly the same results, and both complete so quickly that it is impossible to measure CPU usage for a single execution.  We can, however, compare the I/O statistics for a single run by running the queries with STATISTICS IO ON: Table '#Test'. Scan count 63, logical reads 126, physical reads 0. Table '#Test'. Scan count 01, logical reads 002, physical reads 0. The query with the IN list uses 126 logical reads (and has a ‘scan count’ of 63), while the second query form completes with just 2 logical reads (and a ‘scan count’ of 1).  It is no coincidence that 126 = 63 * 2, by the way.  It is almost as if the first query is doing 63 seeks, compared to one for the second query. In fact, that is exactly what it is doing.  There is no indication of this in the graphical plan, or the tool-tip that appears when you hover your mouse over the Clustered Index Seek icon.  To see the 63 seek operations, you have click on the Seek icon and look in the Properties window (press F4, or right-click and choose from the menu): The Seek Predicates list shows a total of 63 seek operations – one for each of the values from the IN list contained in the first query.  I have expanded the first seek node to show the details; it is seeking down the clustered index to find the entry with the value 101.  Each of the other 62 nodes expands similarly, and the same information is contained (even more verbosely) in the XML form of the plan. Each of the 63 seek operations starts at the root of the clustered index B-tree and navigates down to the leaf page that contains the sought key value.  Our table is just large enough to need a separate root page, so each seek incurs 2 logical reads (one for the root, and one for the leaf).  We can see the index depth using the INDEXPROPERTY function, or by using the a DMV: SELECT S.index_type_desc, S.index_depth FROM sys.dm_db_index_physical_stats ( DB_ID(N'tempdb'), OBJECT_ID(N'tempdb..#Test', N'U'), 1, 1, DEFAULT ) AS S ; Let’s look now at the Properties window when the Clustered Index Seek from the second query is selected: There is just one seek operation, which starts at the root of the index and navigates the B-tree looking for the first key that matches the Start range condition (id >= 101).  It then continues to read records at the leaf level of the index (following links between leaf-level pages if necessary) until it finds a row that does not meet the End range condition (id <= 169).  Every row that meets the seek range condition is also tested against the Residual Predicate highlighted above (id % 10 > 0), and is only returned if it matches that as well. You will not be surprised that the single seek (with a range scan and residual predicate) is much more efficient than 63 singleton seeks.  It is not 63 times more efficient (as the logical reads comparison would suggest), but it is around three times faster.  Let’s run both query forms 10,000 times and measure the elapsed time: DECLARE @i INTEGER, @n INTEGER = 10000, @s DATETIME = GETDATE() ; SET NOCOUNT ON; SET STATISTICS XML OFF; ; WHILE @n > 0 BEGIN SELECT @i = T.id FROM #Test AS T WHERE T.id IN ( 101,102,103,104,105,106,107,108,109, 111,112,113,114,115,116,117,118,119, 121,122,123,124,125,126,127,128,129, 131,132,133,134,135,136,137,138,139, 141,142,143,144,145,146,147,148,149, 151,152,153,154,155,156,157,158,159, 161,162,163,164,165,166,167,168,169 ) ; SET @n -= 1; END ; PRINT DATEDIFF(MILLISECOND, @s, GETDATE()) ; GO DECLARE @i INTEGER, @n INTEGER = 10000, @s DATETIME = GETDATE() ; SET NOCOUNT ON ; WHILE @n > 0 BEGIN SELECT @i = T.id FROM #Test AS T WHERE T.id >= 101 AND T.id <= 169 AND T.id % 10 > 0 ; SET @n -= 1; END ; PRINT DATEDIFF(MILLISECOND, @s, GETDATE()) ; On my laptop, running SQL Server 2008 build 4272 (SP2 CU2), the IN form of the query takes around 830ms and the range query about 300ms.  The main point of this post is not performance, however – it is meant as an introduction to the next few parts in this mini-series that will continue to explore scans and seeks in detail. When is a seek not a seek?  When it is 63 seeks © Paul White 2011 email: [email protected] twitter: @SQL_kiwi

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