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  • We Are SQLFamily

    - by AllenMWhite
    On Monday, Tom LaRock ( b /@sqlrockstar) presented his #MemeMonday topic as What #SQLFamily Means To Me . The #sqlfamily hash tag is a relatively new one, but is amazingly appropriate. I've been working with relational databases for almost 20 years, and for most of that time I've been the lone DBA. The only one to set things up, explain how things work, fix the problems, make it go faster, etc., etc., yadda, yadda, yadda. I enjoy being 'the guy', but at the same time it gets hard. What if I'm wrong?...(read more)

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  • White Paper on Parallel Processing

    - by Andrew Kelly
      I just ran across what I think is a newly published white paper on parallel  processing in SQL Server 2008 R2. The date is October 2010 but this is the first time I have seen it so I am not 100% sure how new it really is. Maybe you have seen it already but if not I recommend taking a look. So far I haven’t had time to read it extensively but from a cursory look it appears to be quite informative and this is one of the areas least understood by a lot of dba’s. It was authored by Don Pinto...(read more)

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  • Tales of a corrupt SQL log

    Warning: Im a simple dev, not an all powerful DBA with godly powers. This morning, one of my sites was down and DNN reported a problem with the database.  A quick series of tests revealed that the culprit was a corrupted log file. Easy fix I said, I have daily backups so its just a mater of restoring a good copy of the database and log files.  Well, I found out thats not exactly true.  You see, for this database, I have daily file backups and these are not database backups created...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Intermittent Copy/Paste Problem in RDP

    - by Tara Kizer
    If you use RDP to remotely connect to your servers, you've probably encountered a clipboard issue where copy/paste stops working.  A quick Google search on the problem indicates you can easily fix the problem by logging out/logging back in or killing/restarting rdpclip.exe on the remote server.  Here's an article which covers this topic. But what do you do when copy/paste is intermittent?  It works one second, stops working for 5-30 seconds, and then on its own starts working again.  This is what’s occurring in our new non-production environment.  The DBA team is setting up 16 new physical servers and 5 new virtual machines.  I haven’t found a server where this ISN’T happening.  This intermittent copy/paste issue is driving me crazy!

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  • Problem installing Oracle 10g Express edition

    - by abhi
    I have installed Oracle 10g Express edition in Ubuntu 10.10 and it doesn't show or ask to give my password during installation. When I click on "start database" it gave the warning "Operation failed, abhi is not a member of 'dba' group." and when clink on "Run SQL command line" it shows /usr/lib/oracle/xe/app/oracle/product/10.2.0/server/bin/nls_lang.sh: 114: [[: not found When I click on "GOTO Database home page", it opens Mozilla's "Ubuntu Google search page". Can anyone help me get my Oracle to work or tell me how to remove that because it is also not getting removed. I tried all the commands that are given as suggestions by Ubuntu. Please help me because I don't want to format my Ubuntu.

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  • Why Choose Oracle University?

    - by Shen Chen
    Get Specialized Training & Certification from ExpertOracle Instructors - with a 100% Satisfaction Guarantee. 5 Reasons to Enroll in Oracle Certification or Training 1. Career Growth: our curriculum is developed to teach you skills that directly align with real-life IT jobs. 2. Salary Advancement: Certification magazine found that Oracle Certified Professionals earn higher salaries when compared to other DBA or Developer professionals. 3. Expert Instruction: learn Oracle from the same team involved in Oracle product development. 4. Flexible Learning Options: train from anywhere, at any time. Pick the format that matches your learning style & schedule. 5. 100 % Student Satisfaction Guarantee: if you’re not completely satisfied with your training or certification experience, you can re-take the same class for free.

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  • Oracle12c ist da: Neue Features für Entwicker

    - by Carsten Czarski
    Das Warten hat ein Ende. Oracle12c Release 1 steht zum Download bereit. Oracle12c bringt eine Reihe neuer Funktionen für SQL, PL/SQL und APEX Entwickler mit. Mit SQL Pattern Matching, Identify Columns, Code Based Security seien nur drei Beispiele genannt. In unserem aktuellen Community Tipp stellen wir 12 neue Features für Entwickler vor - erfahren Sie, wie Sie mit Oracle12c noch schneller und effizienter entwickeln können. Automatische Sequences und Identity Columns SQL und PL/SQL: Erweiterungen und Verbesserungen PL/SQL: Rechte, Rollen und mehr Oracle Multitenant und APEX SQL Pattern Matching Wann ist die Zeile gültig: Valid Time Temporal : Bei den Kollegen der DBA Community finden Sie entsprechend eine Übersicht mit den für Administratoren und den Datenbankbetrieb interessanten Neuerungen.

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  • Unexpected advantage of Engineered Systems

    - by user12244672
    It's not surprising that Engineered Systems accelerate the debugging and resolution of customer issues. But what has surprised me is just how much faster issue resolution is with Engineered Systems such as SPARC SuperCluster. These are powerful, complex, systems used by customers wanting extreme database performance, app performance, and cost saving server consolidation. A SPARC SuperCluster consists or 2 or 4 powerful T4-4 compute nodes, 3 or 6 extreme performance Exadata Storage Cells, a ZFS Storage Appliance 7320 for general purpose storage, and ultra fast Infiniband switches.  Each with its own firmware. It runs Solaris 11, Solaris 10, 11gR2, LDoms virtualization, and Zones virtualization on the T4-4 compute nodes, a modified version of Solaris 11 in the ZFS Storage Appliance, a modified and highly tuned version of Oracle Linux running Exadata software on the Storage Cells, another Linux derivative in the Infiniband switches, etc. It has an Infiniband data network between the components, a 10Gb data network to the outside world, and a 1Gb management network. And customers can run whatever middleware and apps they want on it, clustered in whatever way they want. In one word, powerful.  In another, complex. The system is highly Engineered.  But it's designed to run general purpose applications. That is, the physical components, configuration, cabling, virtualization technologies, switches, firmware, Operating System versions, network protocols, tunables, etc. are all preset for optimum performance and robustness. That improves the customer experience as what the customer runs leverages our technical know-how and best practices and is what we've tested intensely within Oracle. It should also make debugging easier by fixing a large number of variables which would otherwise be in play if a customer or Systems Integrator had assembled such a complex system themselves from the constituent components.  For example, there's myriad network protocols which could be used with Infiniband.  Myriad ways the components could be interconnected, myriad tunable settings, etc. But what has really surprised me - and I've been working in this area for 15 years now - is just how much easier and faster Engineered Systems have made debugging and issue resolution. All those error opportunities for sub-optimal cabling, unusual network protocols, sub-optimal deployment of virtualization technologies, issues with 3rd party storage, issues with 3rd party multi-pathing products, etc., are simply taken out of the equation. All those error opportunities for making an issue unique to a particular set-up, the "why aren't we seeing this on any other system ?" type questions, the doubts, just go away when we or a customer discover an issue on an Engineered System. It enables a really honed response, getting to the root cause much, much faster than would otherwise be the case. Here's a couple of examples from the last month, one found in-house by my team, one found by a customer: Example 1: We found a node eviction issue running 11gR2 with Solaris 11 SRU 12 under extreme load on what we call our ExaLego test system (mimics an Exadata / SuperCluster 11gR2 Exadata Storage Cell set-up).  We quickly established that an enhancement in SRU12 enabled an 11gR2 process to query Infiniband's Subnet Manager, replacing a fallback mechanism it had used previously.  Under abnormally heavy load, the query could return results which were misinterpreted resulting in node eviction.  In several daily joint debugging sessions between the Solaris, Infiniband, and 11gR2 teams, the issue was fully root caused, evaluated, and a fix agreed upon.  That fix went back into all Solaris releases the following Monday.  From initial issue discovery to the fix being put back into all Solaris releases was just 10 days. Example 2: A customer reported sporadic performance degradation.  The reasons were unclear and the information sparse.  The SPARC SuperCluster Engineered Systems support teams which comprises both SPARC/Solaris and Database/Exadata experts worked to root cause the issue.  A number of contributing factors were discovered, including tunable parameters.  An intense collaborative investigation between the engineering teams identified the root cause to a CPU bound networking thread which was being starved of CPU cycles under extreme load.  Workarounds were identified.  Modifications have been put back into 11gR2 to alleviate the issue and a development project already underway within Solaris has been sped up to provide the final resolution on the Solaris side.  The fixed SPARC SuperCluster configuration greatly aided issue reproduction and dramatically sped up root cause analysis, allowing the correct workarounds and fixes to be identified, prioritized, and implemented.  The customer is now extremely happy with performance and robustness.  Since the configuration is common to other customers, the lessons learned are being proactively rolled out to other customers and incorporated into the installation procedures for future customers.  This effectively acts as a turbo-boost to performance and reliability for all SPARC SuperCluster customers.  If this had occurred in a "home grown" system of this complexity, I expect it would have taken at least 6 months to get to the bottom of the issue.  But because it was an Engineered System, known, understood, and qualified by both the Solaris and Database teams, we were able to collaborate closely to identify cause and effect and expedite a solution for the customer.  That is a key advantage of Engineered Systems which should not be underestimated.  Indeed, the initial issue mitigation on the Database side followed by final fix on the Solaris side, highlights the high degree of collaboration and excellent teamwork between the Oracle engineering teams.  It's a compelling advantage of the integrated Oracle Red Stack in general and Engineered Systems in particular.

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  • Other SCOM users at SQLSaturday #65 Vancouver?

    - by merrillaldrich
    After a little hair-graying fun around passport renewal and family logistics, it looks like I'll be at the Vancouver SQLSaturday ! I am pumped. (I was entirely convinced they would call it "SQLSaturd' eh?" and I'm frankly a little disappointed about the name... :-) I'm on the tail end of a three-month deployment of System Center Operations Manager with the SQL management pack - if you are a DBA and SCOM user, too, I'd love to meet you and talk shop at the SQLSaturday event. Please drop me a line...(read more)

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  • Knowing your user is key--Part 1: Motivation

    - by erikanollwebb
    I was thinking where the best place to start in this blog would be and finally came back to a theme that I think is pretty critical--successful gamification in the enterprise comes down to knowing your user.  Lots of folks will say that gamification is about understanding that everyone is a gamer.  But at least in my org, that argument won't play for a lot of people.  Pun intentional.  It's not that I don't see the attraction to the idea--really, very few people play no games at all.  If they don't play video games, they might play solitaire on their computer.  They may play card games, or some type of sport.  Mario Herger has some great facts on how much game playing there is going on at his Enterprise-Gamification.com website. But at the end of the day, I can't sell that into my organization well.  We are Oracle.  We make big, serious software designed run your whole business.  We don't make Angry Birds out of your financial reporting tools.  So I stick with the argument that works better.  Gamification techniques are really just good principals of user experience packaged a little differently.  Feedback?  We already know feedback is important when using software.  Progress indicators?  Got that too.  Game mechanics may package things in a more explicit way but it's not really "new".  To know how to use game mechanics, and what a user experience team is important for, is totally understanding who our users are and what they are motivated by. For several years, I taught college psychology courses, including Motivation.  Motivation is generally broken down into intrinsic and extrinsic motivation.  There's intrinsic, which comes from within the individual.  And there's extrinsic, which comes from outside the individual.  Intrinsic motivation is that motivation that comes from just a general sense of pleasure in the doing of something.  For example, I like to cook.  I like to cook a lot.  The kind of cooking I think is just fun makes other people--people who don't like to cook--cringe.  Like the cake I made this week--the star-spangled rhapsody from The Cake Bible: two layers of meringue, two layers of genoise flavored with a raspberry eau de vie syrup, whipped cream with berries and a mousseline buttercream, also flavored with raspberry liqueur and topped with fresh raspberries and blueberries. I love cooking--I ask for cooking tools for my birthday and Christmas, I take classes like sushi making and knife skills for fun.  I like reading about you can make an emulsion of egg yolks, melted butter and lemon, cook slowly and transform them into a sauce hollandaise (my use of all the egg yolks that didn't go into the aforementioned cake).  And while it's nice when people like what I cook, I don't do it for that.  I do it because I think it's fun.  My former boss, Ultan Ó Broin, loves to fish in the sea off the coast of Ireland.  Not because he gets prizes for it, or awards, but because it's fun.  To quote a note he sent me today when I asked if having been recently ill kept him from the beginning of mackerel season, he told me he had already been out and said "I can fish when on a deathbed" (read more of Ultan's work, see his blogs on User Assistance and Translation.). That's not the kind of intensity you get about something you don't like to do.  I'm sure you can think of something you do just because you like it. So how does that relate to gamification?  Gamification in the enterprise space is about uncovering the game within work.  Gamification is about tapping into things people already find motivating.  But to do that, you need to know what that user is motivated by. Customer Relationship Management (CRM) is one of those areas where over-the-top gamification seems to work (not to plug a competitor in this space, but you can search on what Bunchball* has done with a company just a little north of us on 101 for the CRM crowd).  Sales people are naturally competitive and thrive on that plus recognition of their sales work.  You can use lots of game mechanics like leaderboards and challenges and scorecards with this type of user and they love it.  Show my whole org I'm leading in sales for the quarter?  Bring it on!  However, take the average accountant and show how much general ledger activity they have done in the last week and expose it to their whole org on a leaderboard and I think you'd see a lot of people looking for a new job.  Why?  Because in general, accountants aren't extraverts who thrive on competition in their work.  That doesn't mean there aren't game mechanics that would work for them, but they won't be the same game mechanics that work for sales people.  It's a different type of user and they are motivated by different things. To break this up, I'll stop here and post now.  I'll pick this thread up in the next post. Thoughts? Questions? *Disclosure: To my knowledge, Oracle has no relationship with Bunchball at this point in time.

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  • Which of Your Stored Procedures are Using the Most Resources?

    Dynamic Management Views and Functions aren't always easy to understand. However, they are the easiest way of finding out which of your stored procedures are using up the most resources. Greg takes the time to explain how and why these DMVs and DMFs get their information. Suddenly, it all gets clearer. Join SQL Backup’s 35,000+ customers to compress and strengthen your backups "SQL Backup will be a REAL boost to any DBA lucky enough to use it." Jonathan Allen. Download a free trial now.

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  • Existing Instance, Shiny New Disks

    - by merrillaldrich
    Migrating an Instance of SQL Server to New Disks I get to do something pretty entertaining this week – migrate SQL instances on a 2008 cluster from one disk array to another! Zut alors! I am so excited I can hardly contain myself, so let’s get started. (Only a DBA could love this stuff, am I right? I know.) Anyway, here’s one method of many to migrate your data. Assumption : this is a host-based migration, which just means I’m using the Windows file system to push the data from one set of SAN disks...(read more)

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  • LINQ Lycanthropy: Transformations into LINQ

    LINQ is one of the few technologies that you can start to use without a lot of preliminary learning. Also, it lends itself to learning by trying out examples. With Michael Sorens' help, you can watch as your conventional C# code changes to ravenous LINQ before your very eyes. Join SQL Backup’s 35,000+ customers to compress and strengthen your backups "SQL Backup will be a REAL boost to any DBA lucky enough to use it." Jonathan Allen. Download a free trial now.

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  • Windows: starting sqlplus in new window from cygwin bash

    - by katsumii
    When I start sqlplus, more often than not, I want it to start in new window,whether it be on Linux/Solaris GNOME or Windows.I seldom use GNOME so I never bothered to figure out how.On Windows, one can use Windows menu or Win+R "Run" dialog but I prefer usingbash. Because, this way, I can keep the history in ~/.bash_history file.There are 2 ways. Using cmd.exe or cygstart.For example, to start default sqlplus.exe to connect to default local instance. $ cmd /c "start sqlplus sys/oracle as sysdba" 2nd example. To start sqlplus in 2nd Oracle home and to connect to non-default local instance. $ ORACLE_SID=orcl cygstart /cygdrive/g/app/product/11.2.0.3/dbhome_1/BIN/sqlplus scott I hope this tip helps reducing your DBA time.

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  • Free eBook: 45 Database Performance Tips for Developers

    As a developer, if you need to go into the database and write queries, design tables, or determine the configuration of your SQL Server Systems, these tips should help make sure you're not unnecessarily sacrificing database performance. This eBook has 45 easy tips to improve the performance of your indexes and T-SQL queries, and hunt down problems within ORM tools and database design. Save 45% on our top SQL Server database administration tools. Together they make up the SQL DBA Bundle, which supports your core tasks and helps your day run smoothly. Download a free trial now.

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  • You couldn't write it - Expired SA account

    - by GrumpyOldDBA
    This is the stuff of DBA nightmares ! email trail: Q. Can you reset the SA account on server XXXXX, we think it has expired and now no-one can work. Connect to Server: Surely no-one would set up a Server with an sa account which expires? Thankfully not. Find sa password and change connection to use SA account. Connect without issue. Me. Have checked Server and account is fine. A. Thanks that's great, you've fixed it we can all work now....(read more)

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  • World Backup Day

    - by red(at)work
    Here at Red Gate Towers, the SQL Backup development team have been hunkered down in their shed for the last few months, with the toolbox, blowtorch and chamois leather out, upgrading SQL Backup. When we started, autumn leaves were falling. Now we're about to finish, spring flowers are budding. If not quite a gleaming new machine, at the very least a familiar, reliable engine with some shiny new bits on it will trundle magnificently out of the workshop. One of the interesting things I've noticed about working on software development teams is that the team is together for so long 'implementing' stuff - designing, coding, testing, fixing bugs and so on - that you occasionally forget why you're doing what you're doing. Doubt creeps in. It feels like a long time since we launched this project in a fanfare of optimism and enthusiasm, and all that clarity of purpose and mission "yee-haw" has dissipated with the daily pressures of development. Every now and again, we look up from our bunker and notice all those thousands of users out there, with their different configurations and working practices and each with their own set of problems and requirements, and we ask ourselves "does anyone care about what we're doing?" Has the world moved on while we've been busy? Could we have been doing something more useful with the time and talent of all these excellent people we've assembled? In truth, you can research and test and validate all you like, but you never really know if you've done the right thing (or at least, something valuable for some users) until you release. All projects suffer this insecurity. If they don't, maybe you're not worrying enough about what you're building. The two enemies of software development are certainty and complacency. Oh, and of course, rival teams with Nerf guns. The goal of SQL Backup 7 is to make it so easy to schedule regular restores of your backups that you have no excuse not to. Why schedule a restore? Because your data is not as good as your last backup. It's only as good as your last successful restore. If you're not checking your backups by restoring them and running an integrity check on the database, you're only doing half the job. It seems that most DBAs know that this is best practice, but it can be tricky and time-consuming to set up, so it's one of those tasks that can get forgotten in the midst all the other demands on their time. Sometimes, they're just too busy firefighting. But if it was simple to do? That was our inspiration for SQL Backup 7. So it was heartening to read Brent Ozar's blog post the other day about World Backup Day. To be honest, I'd never heard of World Backup Day (Talk Like a Pirate Day, yes, but not this one); however, its emphasis on not just backing up your data but checking the validity of those backups was exactly the same message we had in mind when building SQL Backup 7. It's printed on a piece of A3 above our planning board - "Make backup verification so easy to do that no DBA has an excuse for not doing it" It's the missing piece that completes the puzzle. Simple idea, great concept, useful feature, but, as it turned out, far from straightforward to implement. The problem is the future. As Marty McFly discovered over the course of three movies, the future is uncertain and hard to predict - so when you are scheduling a restore to take place an hour, day, week or month after the backup, there are all kinds of questions that you wouldn't normally have to consider. Where will this backup live? Will it even exist at the time? Will it be split into multiple files? What will the file names be? Will it be encrypted? What files should it be restored to? SQL Backup needs to know what to expect at the time the restore job is actually run. Of course, a DBA will know the answer to all these questions, but to deliver the whole point of version 7, we wanted to make it easy for them to input that information into SQL Backup. We think we've done that. When you create your scheduled backup job, there is now an option to create a "reminder" to follow it up with a scheduled restore to verify the resulting backups. Actually, it's much more than a reminder, as it stores all the relevant data so you can click it and pre-populate the wizard with all the right settings to set up your verification restores. Simple. But, what do you think? We'd love you to try it. Post by Brian Harris

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  • Building a Repository Pattern against an EF 5 EDMX Model - Part 1

    - by Juan
    I am part of a year long plus project that is re-writing an existing application for a client.  We have decided to develop the project using Visual Studio 2012 and .NET 4.5.  The project will be using a number of technologies and patterns to include Entity Framework 5, WCF Services, and WPF for the client UI.This is my attempt at documenting some of the successes and failures that I will be coming across in the development of the application.In building the data access layer we have to access a database that has already been designed by a dedicated dba. The dba insists on using Stored Procedures which has made the use of EF a little more difficult.  He will not allow direct table access but we did manage to get him to allow us to use Views.  Since EF 5 does not have good support to do Code First with Stored Procedures, my option was to create a model (EDMX) against the existing database views.   I then had to go select each entity and map the Insert/Update/Delete functions to their respective stored procedure. The next step after I had completed mapping the stored procedures to the entities in the EDMX model was to figure out how to build a generic repository that would work well with Entity Framework 5.  After reading the blog posts below, I adopted much of their code with some changes to allow for the use of Ninject for dependency injection.http://www.tcscblog.com/2012/06/22/entity-framework-generic-repository/ http://www.tugberkugurlu.com/archive/generic-repository-pattern-entity-framework-asp-net-mvc-and-unit-testing-triangle IRepository.cs public interface IRepository : IDisposable where T : class { void Add(T entity); void Update(T entity, int id); T GetById(object key); IQueryable Query(Expression> predicate); IQueryable GetAll(); int SaveChanges(); int SaveChanges(bool validateEntities); } GenericRepository.cs public abstract class GenericRepository : IRepository where T : class { public abstract void Add(T entity); public abstract void Update(T entity, int id); public abstract T GetById(object key); public abstract IQueryable Query(Expression> predicate); public abstract IQueryable GetAll(); public int SaveChanges() { return SaveChanges(true); } public abstract int SaveChanges(bool validateEntities); public abstract void Dispose(); } One of the issues I ran into was trying to do an update. I kept receiving errors so I posted a question on Stack Overflow http://stackoverflow.com/questions/12585664/an-object-with-the-same-key-already-exists-in-the-objectstatemanager-the-object and came up with the following hack. If someone has a better way, please let me know. DbContextRepository.cs public class DbContextRepository : GenericRepository where T : class { protected DbContext Context; protected DbSet DbSet; public DbContextRepository(DbContext context) { if (context == null) throw new ArgumentException("context"); Context = context; DbSet = Context.Set(); } public override void Add(T entity) { if (entity == null) throw new ArgumentException("Cannot add a null entity."); DbSet.Add(entity); } public override void Update(T entity, int id) { if (entity == null) throw new ArgumentException("Cannot update a null entity."); var entry = Context.Entry(entity); if (entry.State == EntityState.Detached) { var attachedEntity = DbSet.Find(id); // Need to have access to key if (attachedEntity != null) { var attachedEntry = Context.Entry(attachedEntity); attachedEntry.CurrentValues.SetValues(entity); } else { entry.State = EntityState.Modified; // This should attach entity } } } public override T GetById(object key) { return DbSet.Find(key); } public override IQueryable Query(Expression> predicate) { return DbSet.Where(predicate); } public override IQueryable GetAll() { return Context.Set(); } public override int SaveChanges(bool validateEntities) { Context.Configuration.ValidateOnSaveEnabled = validateEntities; return Context.SaveChanges(); } #region IDisposable implementation public override void Dispose() { if (Context != null) { Context.Dispose(); GC.SuppressFinalize(this); } } #endregion IDisposable implementation } At this point I am able to start creating individual repositories that are needed and add a Unit of Work.  Stay tuned for the next installment in my path to creating a Repository Pattern against EF5.

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  • Implementing a Custom Coherence PartitionAssignmentStrategy

    - by jpurdy
    A recent A-Team engagement required the development of a custom PartitionAssignmentStrategy (PAS). By way of background, a PAS is an implementation of a Java interface that controls how a Coherence partitioned cache service assigns partitions (primary and backup copies) across the available set of storage-enabled members. While seemingly straightforward, this is actually a very difficult problem to solve. Traditionally, Coherence used a distributed algorithm spread across the cache servers (and as of Coherence 3.7, this is still the default implementation). With the introduction of the PAS interface, the model of operation was changed so that the logic would run solely in the cache service senior member. Obviously, this makes the development of a custom PAS vastly less complex, and in practice does not introduce a significant single point of failure/bottleneck. Note that Coherence ships with a default PAS implementation but it is not used by default. Further, custom PAS implementations are uncommon (this engagement was the first custom implementation that we know of). The particular implementation mentioned above also faced challenges related to managing multiple backup copies but that won't be discussed here. There were a few challenges that arose during design and implementation: Naive algorithms had an unreasonable upper bound of computational cost. There was significant complexity associated with configurations where the member count varied significantly between physical machines. Most of the complexity of a PAS is related to rebalancing, not initial assignment (which is usually fairly simple). A custom PAS may need to solve several problems simultaneously, such as: Ensuring that each member has a similar number of primary and backup partitions (e.g. each member has the same number of primary and backup partitions) Ensuring that each member carries similar responsibility (e.g. the most heavily loaded member has no more than one partition more than the least loaded). Ensuring that each partition is on the same member as a corresponding local resource (e.g. for applications that use partitioning across message queues, to ensure that each partition is collocated with its corresponding message queue). Ensuring that a given member holds no more than a given number of partitions (e.g. no member has more than 10 partitions) Ensuring that backups are placed far enough away from the primaries (e.g. on a different physical machine or a different blade enclosure) Achieving the above goals while ensuring that partition movement is minimized. These objectives can be even more complicated when the topology of the cluster is irregular. For example, if multiple cluster members may exist on each physical machine, then clearly the possibility exists that at certain points (e.g. following a member failure), the number of members on each machine may vary, in certain cases significantly so. Consider the case where there are three physical machines, with 3, 3 and 9 members each (respectively). This introduces complexity since the backups for the 9 members on the the largest machine must be spread across the other 6 members (to ensure placement on different physical machines), preventing an even distribution. For any given problem like this, there are usually reasonable compromises available, but the key point is that objectives may conflict under extreme (but not at all unlikely) circumstances. The most obvious general purpose partition assignment algorithm (possibly the only general purpose one) is to define a scoring function for a given mapping of partitions to members, and then apply that function to each possible permutation, selecting the most optimal permutation. This would result in N! (factorial) evaluations of the scoring function. This is clearly impractical for all but the smallest values of N (e.g. a partition count in the single digits). It's difficult to prove that more efficient general purpose algorithms don't exist, but the key take away from this is that algorithms will tend to either have exorbitant worst case performance or may fail to find optimal solutions (or both) -- it is very important to be able to show that worst case performance is acceptable. This quickly leads to the conclusion that the problem must be further constrained, perhaps by limiting functionality or by using domain-specific optimizations. Unfortunately, it can be very difficult to design these more focused algorithms. In the specific case mentioned, we constrained the solution space to very small clusters (in terms of machine count) with small partition counts and supported exactly two backup copies, and accepted the fact that partition movement could potentially be significant (preferring to solve that issue through brute force). We then used the out-of-the-box PAS implementation as a fallback, delegating to it for configurations that were not supported by our algorithm. Our experience was that the PAS interface is quite usable, but there are intrinsic challenges to designing PAS implementations that should be very carefully evaluated before committing to that approach.

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  • LinuxCon North America 2014

    - by Chris Kawalek
    As the first day of LinuxCon North America 2014 draws to a close, we want to thank all the folks that stopped by our booth today! If you're at the show, please stop by our booth #204 and have a chat with our experts. And you won't want to miss these Linux and virtualization related sessions coming up tomorrow and Friday: Thursday Aug 21 - Static Analysis in the Linux Kernel Using Smatch - Dan Carpenter, Oracle Friday Aug 22 - The Proper Care of Feeding of MySQL Database for Linux Admins Who Also Have DBA duties - Morgan Tocker, Oracle Friday Aug 22 - Why Use Xen for Large Scale Enterprise Deployments, Konrad Rzeszutek Wilk , Oracle We look forward to meeting with you and we hope you enjoy the rest of LinuxCon North America 2014! 

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  • Simple way to create a SQL Server Job Using T-SQL

    Sometimes we have a T-SQL process that we need to run that takes some time to run or we want to run it during idle time on the server. We could create a SQL Agent job manually, but is there any simple way to create a scheduled job? The seven tools in the SQL DBA Bundle support your core SQL Server database administration tasks.Make backups a breeze! Enjoy trouble-free troubleshooting! Make the most of monitoring! Download a free trial now.

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  • How to make transition from one-man to small team successfull

    - by si2w
    I have started a big project 1 1/2 ago. It's time to have some help to face the future challenges. Actually I'm the engineer, the architect, the dba, the sysadmin etc... The transistion is not so simple and it's difficult to find the good person. When we will find this person, what's the best ways to manage him/her to give enough freedom to be happy and productive but have a clean, fast, reuseable, working, ... code ? Is there good books you advice ? Thanks !

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  • The ETL from Hell - Diagnosing Batch System Performance Issues

    Too often, the batch systems that underlie a lot of database processing just grow without conscious design. When runs start to extend beyond their allotted time, and tuning no longer solves the problem, it is often discovered that batches are run in series, with draconian error handling. It is time to impose some rational design, and Nigel is a seasoned healer of batch processes. The seven tools in the SQL DBA Bundle support your core SQL Server database administration tasks.Make backups a breeze! Enjoy trouble-free troubleshooting! Make the most of monitoring! Download a free trial now.

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  • Column-Level Encryption in SQL Server

    Beginning with SQL Server 2005, column-level encryption and decryption capabilities were made available within the database, providing a solution for situations where one-off types of data need to be secured beyond your existing authorization, authentication or firewall settings. This article provides an overview and example of securing a column using native SQL Server cryptography functions. Join SQL Backup’s 35,000+ customers to compress and strengthen your backups "SQL Backup will be a REAL boost to any DBA lucky enough to use it." Jonathan Allen. Download a free trial now.

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  • Steps to add Log Shipping monitor into an existing SQL Server

    I have a requirement to add the Log Shipping Monitor for an existing installation. I have heard you can only complete this by rebuilding the Log Shipping infrastructure. Is that true? Are there any other options? In this tip I will explain how we can add the Log Shipping monitor to a SQL Server 2005, 2008, 2008 R2 or 2012 environment without rebuilding the Log Shipping installation. "It's the freaking iPhone of SQL monitoring""Everyone just gets it… that has tremendous value" - Rob Sullivan, DBA, IdeasRun. Get started with SQL Monitor today - download a free trial.

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