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• Chicago SQL Saturday

  - by Johnm

  This past Saturday, April 17, 2010, I journeyed North to the great city of Chicago for some SQL Server fun, learning and fellowship. The Chicago edition of this grassroots phenomenon was the 31st scheduled SQL Saturday since the program's birth in late 2007. The Chicago SQL Saturday consisted of four tracks with eight sessions each and was a very energetic and fast paced day for the 300+/- SQL Server enthusiasts in attendance. The speaker line up included national notables such as Kevin Kline, Brent Ozar, and Brad McGehee. My hometown of Indianapolis was well represented in the speaker line up with Arie Jones, Aaron King and Derek Comingore. The day began with a very humorous keynote by Kevin Kline and Brent Ozar who emphasized the importance of community events such as SQL Saturday and the monthly user group meetings. They also brilliantly included the impact that getting involved in the SQL community through social media can have on your professional career. My approach to the day was to try to experience as much of the event as I could, so there were very few sessions that I attended for their full duration. I leaped from session to session like a bumble bee, gleaning bits of nectar from each session. Amid these leaps I took the opportunity to briefly chat with some of the in-the-queue speakers as well as other attendees that wondered the hallways. I especially enjoyed a great discussion with Devin Knight about his plans regarding the upcoming Jacksonville SQL Saturday as well as an interesting SQL interpretation of the Iron Chef, which I think would catch on like wild-fire. There were two sessions that stood out as exceptional. So much so that I could not pull myself away: Kevin Kline presented on "SQL Server Internals and Architecture". This session could have been classified as one that is intended for the beginner. Kevin even personally warned me of such as I entered the room. I am a believer in revisiting the basics regardless of the level of your mastery, so I entered into this session in that spirit. It was a very clear and precise presentation. Masterfully illustrated and demonstrated. Brad McGehee presented on "How and When to Use Indexed Views". This was a topic that I was recently exploring and was considering to for use in an integration project. Brad effectively communicated the complexity of this feature and what is involved to gain their full benefit. It was clear at the conclusion of this session that it was not the right feature for my specific needs. Overall, the event was a great success. The use of volunteers, from an attendee's perspective was masterful. The only recommendation that I would have for the next Chicago SQL Saturday would be to include more time in between sessions to permit some level of networking among the attendees, one-on-one questions for speakers and visits to the sponsor booths. Congratulations to Wendy Pastrick, Ted Krueger, and Aaron Lowe for their efforts and a very successful SQL Saturday!

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• July, the 31 Days of SQL Server DMO’s – Day 29 (sys.dm_os_buffer_descriptors)

  - by Tamarick Hill

  The sys.dm_os_buffer_descriptors Dynamic Management View gives you a look into the data pages that are currently in your SQL Server buffer pool. Just in case you are not familiar with some of the internals to SQL Server and how the engine works, SQL Server only works with objects that are in memory (buffer pool). When an object such as a table needs to be read and it does not exist in the buffer pool, SQL Server will read (copy) the necessary data page(s) from disk into the buffer pool and cache it. Caching takes place so that it can be reused again and prevents the need of expensive physical reads. To better illustrate this DMV, lets query it against our AdventureWorks2012 database and view the result set. SELECT * FROM sys.dm_os_buffer_descriptors WHERE database_id = db_id('AdventureWorks2012') The first column returned from this result set is the database_id column which identifies the specific database for a given row. The file_id column represents the file that a particular buffer descriptor belongs to. The page_id column represents the ID for the data page within the buffer. The page_level column represents the index level of the data page. Next we have the allocation_unit_id column which identifies a unique allocation unit. An allocation unit is basically a set of data pages. The page_type column tells us exactly what type of page is in the buffer pool. From my screen shot above you see I have 3 distinct type of Pages in my buffer pool, Index, Data, and IAM pages. Index pages are pages that are used to build the Root and Intermediate levels of a B-Tree. A Data page would represent the actual leaf pages of a clustered index which contain the actual data for the table. Without getting into too much detail, an IAM page is Index Allocation Map page which track GAM (Global Allocation Map) pages which in turn track extents on your system. The row_count column details how many data rows are present on a given page. The free_space_in_bytes tells you how much of a given data page is still available, remember pages are 8K in size. The is_modified signifies whether or not a page has been changed since it has been read into memory, .ie a dirty page. The numa_node column represents the Nonuniform memory access node for the buffer. Lastly is the read_microsec column which tells you how many microseconds it took for a data page to be read (copied) into the buffer pool. This is a great DMV for use when you are tracking down a memory issue or if you just want to have a look at what type of pages are currently in your buffer pool. For more information about this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms173442.aspx Follow me on Twitter @PrimeTimeDBA

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• Analysis Services Tabular books #ssas #tabular

  - by Marco Russo (SQLBI)

  Many people are looking for books about Analysis Services Tabular. Today there are two books available and they complement each other: Microsoft SQL Server 2012 Analysis Services: The BISM Tabular Model by Marco Russo, Alberto Ferrari and Chris Webb Applied Microsoft SQL Server 2012 Analysis Services: Tabular Modeling by Teo Lachev The book I wrote with Alberto and Chris is a complete guide to create tabular models and has a good coverage about DAX, including how to use it for enriching a semantic model with calculated columns and measures and how to use it for querying a Tabular model. In my experience, DAX as a query language is a very interesting option for custom analytical applications that requires a fast calculation engine, or simply for standard reports running in Reporting Services and accessing a Tabular model. You can freely preview the table of content and read some excerpts from the book on Safari Books Online. The book is in printing and should be shipped within mid-July, so finally it will be very soon on the shelf of all the people already preordered it! The Teo Lachev’s book, covers the full spectrum of Tabular models provided by Microsoft: starting with self-service BI, you have users creating a model with PowerPivot for Excel, publishing it to PowerPivot for SharePoint and exploring data by using Power View; then, the PowerPivot for Excel model can be imported in a Tabular model and published in Analysis Services, adding more control on the model through row-level security and partitioning, for example. Teo’s book follows a step-by-step approach describing each feature that is very good for a beginner that is new to PowerPivot and/or to BISM Tabular. If you need to get the big picture and to start using the products that are part of the new Microsoft wave of BI products, the Teo’s book is for you. After you read the book from Teo, or if you already have a certain confidence with PowerPivot or BISM Tabular and you want to go deeper about internals, best practices, design patterns in just BISM Tabular, then our book is a suggested read: it contains several chapters about DAX, includes discussions about new opportunities in data model design offered by Tabular models, and also provides examples of optimizations you can obtain in DAX and best practices in data modeling and queries. It might seem strange that an author write a review of a book that might seem to compete with his one, but in reality these two books complement each other and are not alternatives. If you have any doubt, buy both: you will be not disappointed! Moreover, Amazon usually offers you a deal to buy three books, including the Visualizing Data with Microsoft Power View, another good choice for getting all the details about Power View.

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• SQLOS and Cloud Infrastructure sessions at PASS Summit 2012

  - by SQLOS Team

  The SQL Pass Summit 2012, the largest yet, is in full swing. Here's a summary of the sessions this week on cloud infrastructure and SQLOS topics. Some of these were today, and you can catch the recordings. One more session takes place on Friday covering SQL Server solution patterns in Windows Azure VMs... Also, catch Thursday's keynote with Quentin Clark which will feature a cool IaaS demo!   SQL Server in Windows Azure VM Sessions CLD-309-A SQLCAT: Best Practices and Lessons Learned on SQL Server in an Azure VM Steve Howard, Arvind Ranasaria - Wednesday 11/6 10:15 This session looked at some best practices to optimize Networking, Memory, Disk IO and high availability based on lessons learned during SQLCat work with customer deployments. Well worth catching the recording.   SQL Server in Azure VM patterns: Hybrid Disaster Recovery, data movement and BI Guy Bowerman, Peter Saddow, Michael Washam, Ross LoForte - Friday 11/9 9:45 Rm 613 [Note: In the guides this has an outdated title.] This session has a focus on SQL Server Azure VM solutions. Starting with the basics and then going deeper into: - New features in the Microsoft Assessment and Planning Toolkit 8.0 to help plan and size SQL VM migrations.- A Look at a Windows Azure VM SQL Server app making use of load balancing and SQL Server high availability features.- A BI case study running SQL BI components in Azure VMs and making use of Windows 8 tiles.- A training class in a VM case study.   SQLOS Sessions DBA-500-HD Inside SQLOS 2012 (half-day session) Bob Ward - Wednesday 11/6 1:30pm Bob Ward from CSS applies his wealth of experience to look at the internals of SQLOS and what's changed in the various SQL 2012 components, including memory, resource governor, scheduler.   DBA-403-M: SQLCAT: Memory Manager Changes in SQL Server 2012 Gus Apostol, Jerome Halmans - 1:30pm Covers the redesigned SQLOS memory manager in SQL Server 2012 including the new page allocator for any size pages (and all that implies), DMVs, demo's. Not sure why this was placed at the same time as the SQLOS half-day session, but since it's recorded it's available for catch-up.   - Guy   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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• Dependency Injection/IoC container practices when writing frameworks

  - by Dave Hillier

  I've used various IoC containers (Castle.Windsor, Autofac, MEF, etc) for .Net in a number of projects. I have found they tend to encourage a number of bad practices. Are there any established practices for IoC container use, particularly when providing a platform/framework? My aim as a framework writer is to make code as simple and as easy to use as possible. I'd rather write one line of code to construct an object than ten or even just two. For example, a couple of code smells that I've noticed and don't have good suggestions to: Large number of parameters (5) for constructors. Creating services tends to be complex; all of the dependencies are injected via the constructor - despite the fact that the components are rarely optional (except for maybe in testing). Lack of private and internal classes; this one may be a specific limitation of using C# and Silverlight, but I'm interested in how it is solved. It's difficult to tell what a frameworks interface is if all the classes are public; it allows me access to private parts that I probably shouldnt touch. Coupling the object lifecycle to the IoC container. It is often difficult to manually construct the dependencies required to create objects. Object lifecycle is too often managed by the IoC framework. I've seen projects where most classes are registered as Singletons. You get a lack of explicit control and are also forced to manage the internals (it relates to the above point, all classes are public and you have to inject them). For example, .Net framework has many static methods. such as, DateTime.UtcNow. Many times I have seen this wrapped and injected as a construction parameter. Depending on concrete implementation makes my code hard to test. Injecting a dependency makes my code hard to use - particularly if the class has many parameters. How do I provide both a testable interface, as well as one that is easy to use? What are the best practices?

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• SQL Saturday #162 Cambridge

  - by Most Valuable Yak (Rob Volk)

  Despite the efforts of American Airlines, this past weekend I attended the first SQL Saturday in the UK!  Hosted by the SQLCambs Chapter of PASS and organized by Mark (b|t) & Lorraine Broadbent, ably assisted by John Martin (b|t), Mark Pryce-Maher (b|t) and other folks whose names I've unfortunately forgotten, it was held at the Crowne Plaza Hotel, which is completely surrounded by Cambridge University. On Friday, they presented 3 pre-conference sessions given by the brilliant American Cloud & DBA Guru, Buck Woody (b|t), the brilliant Danish SQL Server Internals Guru, Mark Rasmussen (b|t), and the brilliant Scottish Business Intelligence Guru and recent Outstanding Pass Volunteer, Jen Stirrup (b|t).  While I would have loved to attend any of their pre-cons (having seen them present several times already), finances and American Airlines ultimately made that impossible.  But not to worry, I caught up with them during the regular sessions and at the speaker dinner.  And I got back the money they all owed me.  (Actually I owed Mark some money) The schedule was jam-packed even with only 4 tracks, there were 8 regular slots, a lunch session for sponsor presentations, and a 15 minute keynote given by Buck Woody, who besides giving an excellent history of SQL Server at Microsoft (and before), also explained the source of the "unknown contact" image that appears in Outlook.  Hint: it's not Buck himself. Amazingly, and against all better judgment, I even got to present at SQL Saturday 162!  I did a 5 minute Lightning Talk on Regular Expressions in SSMS.  I then did a regular 50 minute session on Constraints.  You can download the content for the regular session at that link, and for the regular expression presentation here. I had a great time and had a great audience for both of my sessions.  You would never have guessed this was the first event for the organizers, everything went very smoothly, especially for the number of attendees and the relative smallness of the space.  The event sponsors also deserve a lot of credit for making themselves fit in a small area and for staying through the entire event until the giveaways at the very end. Overall this was one of the best SQL Saturdays I've ever attended and I have to congratulate Mark B, Lorraine, John, Mark P-M, and all the volunteers and speakers for making this an astoundingly hard act to follow!  Well done!

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• Unrated Easy iOS 6.1.4/6.1.3 Unlock/Jailbreak iPhone 5/4S/4/3GS Untehtered System

  - by user171772

  Popular jailbreak tool Unlock-Jailbreak.net – compiled by the iPhone Team – has just been updated with full support for Unlock/Jailbreak iPhone 5/4S/4/3GS iOS 6.1.4 and 6.1.3/6.0.1 Untethered. You may have caught our tutorial, which detailed how one could jailbreak their device tethered using Redsn0w, although since it was a pre-iOS 6.1.1 release, users needed to "point" the tool to the older firmware. Team Unlock-Jailbreak was established few years ago, combines some of the jailbreak and unlock community’s most talented developers all known for producing reliable jailbreaks in the past. This team was assembled in order to develop a reliable untethered jailbreak and unlock iphone 5,4S,4 iOS 6.1 for post-A5 devices, including the iPhone 5, the iPad mini and the latest-generation iPad. This has now been achieved with the just-released userland jailbreak tool, known as Unlock-Jailbreak.net. To Jailbreak and Unlock your iPhone 5/4/4S/3GS iOS 6.1.4 and 6.1.3 visit the official website http://www.Unlock-Jailbreak.net http://www.Unlock-Jailbreak.net was formed in mid 2008 and have successfully jailbroken over 250,000 iPhones worldwide. This is unparalleled by any other service in the industry. They have achieved this by combining a very simple solution with a fantastic customer service department that is available 24/7 through many forms of contact, including telephone. Unlock-Jailbreak from Unlock-Jailbreak.nethas been downloaded by over 250,000 customers located in over 145 countries. To further ensure customers of its products usability, Unlock-Jailbreak offers a 100% full money back guarantee on all orders. Customers dissatisfied with the company’s product will be given a full refund, no questions asked. One good advantage of the software is that the jailbreaking and unlocking process is coampletely reversible and there will be no evidence that the iPhone has been jailbroken and unlocked . iOS 6.1/6.1.4 and 6.1.3 comes with many new features and updates for multitasking and storage. By unlocking and jailbreaking the iPhone,Unlock/Jailbreak iPhone 5/4S/4/3GS iOS 6.1/6.1.4 and 6.1.3/6.0.1 Untethered unleash unlimited possibilities to improve this already fantastic experience and the iPhone FULL potential. Before going through any jailbreak process with Unlock-Jailbreak it is always good housekeeping to perform a full backup of all information on the device. It is unlikely that anything will go wrong during the process but when undertaking any process that modifies the internals of a file system it is always prudent to err on the side of caution.

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• Unit testing in Django

  - by acjohnson55

  I'm really struggling to write effective unit tests for a large Django project. I have reasonably good test coverage, but I've come to realize that the tests I've been writing are definitely integration/acceptance tests, not unit tests at all, and I have critical portions of my application that are not being tested effectively. I want to fix this ASAP. Here's my problem. My schema is deeply relational, and heavily time-oriented, giving my model object high internal coupling and lots of state. Many of my model methods query based on time intervals, and I've got a lot of auto_now_add going on in timestamped fields. So take a method that looks like this for example: def summary(self, startTime=None, endTime=None): # ... logic to assign a proper start and end time # if none was provided, probably using datetime.now() objects = self.related_model_set.manager_method.filter(...) return sum(object.key_method(startTime, endTime) for object in objects) How does one approach testing something like this? Here's where I am so far. It occurs to me that the unit testing objective should be given some mocked behavior by key_method on its arguments, is summary correctly filtering/aggregating to produce a correct result? Mocking datetime.now() is straightforward enough, but how can I mock out the rest of the behavior? I could use fixtures, but I've heard pros and cons of using fixtures for building my data (poor maintainability being a con that hits home for me). I could also setup my data through the ORM, but that can be limiting, because then I have to create related objects as well. And the ORM doesn't let you mess with auto_now_add fields manually. Mocking the ORM is another option, but not only is it tricky to mock deeply nested ORM methods, but the logic in the ORM code gets mocked out of the test, and mocking seems to make the test really dependent on the internals and dependencies of the function-under-test. The toughest nuts to crack seem to be the functions like this, that sit on a few layers of models and lower-level functions and are very dependent on the time, even though these functions may not be super complicated. My overall problem is that no matter how I seem to slice it, my tests are looking way more complex than the functions they are testing.

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• Can I prevent an IDENTIFY PACKET DEVICE command to a specific device at boot?

  - by Brian Spisak

  This is related to a previous question related to installation that is now resolved. I'm opening a new question, because I still need to get my DVD drive working. Problem: Failed boot when my ASUS DRW-24B1/ST DVD drive is attached to my asmedia ASM1061. Symptom: ata8.00: exception Emask 0x52 Sact 0x0 SErr 0xffffffff action 0xe frozen ata8: SError: { blah blah } ata8.00: failed command: IDENTIFY PACKET DEVICE ata8.00: cmd blah blah res blah blah (ATA bus error) ata8.00: status: { DRDY } ata8: hard resetting link Background: The ASM1061 is a PCIe to SATA bridge providing 2 x 6Gb/s ports and is supposed to be fully compliant to SATA specs. I just discovered in the fine print of my ASUS P8Z77-V pro motherboard that "These SATA ports are for data hard drivers only. ATAPI devices are not supported." However, I have already installed Windows 7 using this drive and I can run the Ubuntu 12.04 installer from it as well. The only time I have a problem is during Ubuntu boot when it tries an IDENTIFY PACKET DEVICE which seems to be an ATAPI command. I can't simply switch this device to another SATA port because they are already allocated to other devices. (My chipset's 2 x 6Gb/s are connected to my boot SSD and a fast HDD while the 4 x 3Gb/s ports are running a RAID 5 array.) If this can't be fixed or worked around, I suppose I'll have to go buy SATA add-in card. Blech. Thoughts: If indeed this is a device specific issue (that it doesn't support ATAPI discovery) then I can't expect - is it udev? - to work with it. But, it seems that Windows and even the Ubuntu installer work just fine. So why does udev have a problem? At the end of the day, it would be nice to have the DVD working under Ubuntu, but I can live without it. But, as this is a dual-boot machine, I can't physically disconnect it because I want it to work with Windows. (And physically disconnecting it every time I want to boot Ubuntu is NOT an option. ;-) Questions: Should this be considered a bug? My feelings are that if it works with other OS that it should probably work with Ubuntu as well. How can I work around this problem? I have a limited knowledge of linux internals, but it seems I should be able to somehow tell udev (or whatever is doing the discovery) to ignore that device. Is there a way?

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• SQL 2014 does data the way developers want

  - by Rob Farley

  A post I’ve been meaning to write for a while, good that it fits with this month’s T-SQL Tuesday, hosted by Joey D’Antoni (@jdanton) Ever since I got into databases, I’ve been a fan. I studied Pure Maths at university (as well as Computer Science), and am very comfortable with Set Theory, which undergirds relational database concepts. But I’ve also spent a long time as a developer, and appreciate that that databases don’t exactly fit within the stuff I learned in my first year of uni, particularly the “Algorithms and Data Structures” subject, in which we studied concepts like linked lists. Writing in languages like C, we used pointers to quickly move around data, without a database in sight. Of course, if we had a power failure all this data was lost, as it was only persisted in RAM. Perhaps it’s why I’m a fan of database internals, of indexes, latches, execution plans, and so on – the developer in me wants to be reassured that we’re getting to the data as efficiently as possible. Back when SQL Server 2005 was approaching, one of the big stories was around CLR. Many were saying that T-SQL stored procedures would be a thing of the past because we now had CLR, and that obviously going to be much faster than using the abstracted T-SQL. Around the same time, we were seeing technologies like Linq-to-SQL produce poor T-SQL equivalents, and developers had had a gutful. They wanted to move away from T-SQL, having lost trust in it. I was never one of those developers, because I’d looked under the covers and knew that despite being abstracted, T-SQL was still a good way of getting to data. It worked for me, appealing to both my Set Theory side and my Developer side. CLR hasn’t exactly become the default option for stored procedures, although there are plenty of situations where it can be useful for getting faster performance. SQL Server 2014 is different though, through Hekaton – its In-Memory OLTP environment. When you create a table using Hekaton (that is, a memory-optimized one), the table you create is the kind of thing you’d’ve made as a developer. It creates code in C leveraging structs and pointers and arrays, which it compiles into fast code. When you insert data into it, it creates a new instance of a struct in memory, and adds it to an array. When the insert is committed, a small write is made to the transaction to make sure it’s durable, but none of the locking and latching behaviour that typifies transactional systems is needed. Indexes are done using hashes and using bw-trees (which avoid locking through the use of pointers) and by handling each updates as a delete-and-insert. This is data the way that developers do it when they’re coding for performance – the way I was taught at university before I learned about databases. Being done in C, it compiles to very quick code, and although these tables don’t support every feature that regular SQL tables do, this is still an excellent direction that has been taken. @rob_farley

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• My father wants to learn PHP-MySQL to port his application. What I should do to help?

  - by adijiwa

  My father is a doctor/physician. About 15 years ago he started writing an application to handle his patient's medical records in his clinic at home. The app has the ability to input patient's medical records (obviously), search patients by some criteria, manage medicine stocks, output receipt to printer, and some more CRUDs. He wrote it in dBase III+. A few years later he migrated to FoxPro 2.6 for DOS and finally in a few more years he rewrote his app in Visual FoxPro 9. And now (actually two years ago) he wants to rewrite it in PHP, but he don't know how. The Visual FoxPro version of this app is still running and has no serious problem except sometimes it performs slowly. Usually there are 1-5 concurrent users. The binary and database files are shared via windows share. He did all the coding as a hobby and for free (it is for his own clinic after all). He also use this app in two other offices he managed. Some reasons of why he wants to rewrite in PHP-MySQL: He wants to learn Easier to deploy (?) Easier client setup, need only a browser What should I do to help my father? How should he start? I explored some options: I let my father learn PHP and MySQL (and HTML (and JavaScript?)) from scratch. I create/bundle framework. I'm thinking on bundling CodeIgniter and a web UI framework (any suggestion?) especially to reduce effort on writing presentation codes. What do you think? tl;dr My father (a doctor) wants to rewrite his Visual FoxPro app in PHP-MySQL. He knows very little of PHP and MySQL but he wants to learn. What should I do to help? How should he start? Some facts: My father is 50 years old. His first encounter with a PC is in early 1980s. It was IBM PC with Intel 8088. He knows BASIC. He taught me how to use DOS and how to program with BASIC. The other language he knows fairly well is dBase/FoxPro. I got my bachelor CS degree last year. I know the internals of my father's app because sometime he wants me to help him writing his app. Sorry for my english.

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• What is the most appropriate testing method in this scenario?

  - by Daniel Bruce

  I'm writing some Objective-C apps (for OS X/iOS) and I'm currently implementing a service to be shared across them. The service is intended to be fairly self-contained. For the current functionality I'm envisioning there will be only one method that clients will call to do a fairly complicated series of steps both using private methods on the class, and passing data through a bunch of "data mangling classes" to arrive at an end result. The gist of the code is to fetch a log of changes, stored in a service-internal data store, that has occurred since a particular time, simplify the log to only include the last applicable change for each object, attach the serialized values for the affected objects and return this all to the client. My question then is, how do I unit-test this entry point method? Obviously, each class would have thorough unit tests to ensure that their functionality works as expected, but the entry point seems harder to "disconnect" from the rest of the world. I would rather not send in each of these internal classes IoC-style, because they're small and are only made classes to satisfy the single-responsibility principle. I see a couple possibilities: Create a "private" interface header for the tests with methods that call the internal classes and test each of these methods separately. Then, to test the entry point, make a partial mock of the service class with these private methods mocked out and just test that the methods are called with the right arguments. Write a series of fatter tests for the entry point without mocking out anything, testing the entire functionality in one go. This looks, to me, more like "integration testing" and seems brittle, but it does satisfy the "only test via the public interface" principle. Write a factory that returns these internal services and take that in the initializer, then write a factory that returns mocked versions of them to use in tests. This has the downside of making the construction of the service annoying, and leaks internal details to the client. Write a "private" initializer that take these services as extra parameters, use that to provide mocked services, and have the public initializer back-end to this one. This would ensure that the client code still sees the easy/pretty initializer and no internals are leaked. I'm sure there's more ways to solve this problem that I haven't thought of yet, but my question is: what's the most appropriate approach according to unit testing best practices? Especially considering I would prefer to write this test-first, meaning I should preferably only create these services as the code indicates a need for them.

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• SQL Server Memory Manager Changes in Denali

  - by SQLOS Team

  The next version of SQL Server will contain significant changes to the memory manager component.  The memory manager component has been rewritten for Denali.  In the previous versions of SQL Server there were two distinct memory managers.  There was one memory manager which handled allocation sizes of 8k or less and another for greater than 8k.  For Denali there will be one memory manager for all allocation sizes.   The majority of the changes will be transparent to the end user.  However, some changes will be visible to the user.  These are listed below: ·         The ‘max server memory’ configuration option has new lower limits.  Specifically, 32-bit versions of SQL Server will have a lower limit of 64 MB.  The 64-bit versions will have a lower limit of 128 MB. ·         All memory allocations by SQL Server components will observe the ‘max server memory’ configuration option.  In previous SQL versions only the 8k allocations were limited the ‘max server memory’ configuration option.  Allocations larger than 8k weren’t constrained. ·         DMVs which refer to memory manager internals have been modified.  This includes adding or removing columns and changing column names. ·         The memory manager configuration messages in the error log have minor changes. ·         DBCC memorystatus output has been changed. ·         Address Windowing Extensions (AWE) has been deprecated.   In the next blog post I will discuss the changes to the memory manager DMVs in greater detail.  In future blog posts I will discuss the other changes in greater detail.  

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• Force dual-mono audio (L+L or R+R) in Youtube video playback for one-channel audio movies

  - by jakub.g

  Occasionally, I find Youtube videos that have only one audio channel (only left or only right); example video (left channel only). This is quite annoying, especially with headphones on, as I hear sound in one ear, and no sound in the other. So, I want to be able to easily force dual mono (Left+Left or Right+Right) when I find that kind of video, and switch to normal stereo after I finish watching it. I have my headphones plugged well / I don't create audio/video - I want it for real-time playback only, In Windows audio config, setting balance 100% to Left / Right doesn't help (I have either still only left when moved to left, and no sound at all when moved to right), I've checked all the configurations in Control Panel > Sounds and Audio Devices > Audio > Sound Playback > Advanced like suggested in this post, in conjunction with moving balance left/right, and it doesn't seem to have any impact on actual sound I hear in headphones, No need to mix L with R, I just want L+L or R+R, I prefer software solutions to buying a stereo-to-mono adapter, Free solutions please, no $$$ ones, neither trials etc., In Control Panel > Realtek HD Sound Effect Manager I can turn on various mumbo-jumbo effects like: Concert Hall / Hangar / Bathroom / whatever environment (and in fact it makes the sound appear in two ears, but well, it's ridiculous to do this;), but there is no Dual Mono option. Finally, I know I can force L+L or R+R in VLC Player which supports Youtube (well, a little hack is needed, because Youtube internals change from time to time) but it is not very convenient to launch VLC just to play Youtube video - I want to keep it in the browser, I use Firefox generally (but well, if I don't find easier way, I will launch it in VLC).

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• Rsyslog stops sending data to remote server after log rotation

  - by Vincent B.

  In my configuration, I have rsyslog who is in charge of following changes of /home/user/my_app/shared/log/unicorn.stderr.log using imfile. The content is sent to another remote logging server using TCP. When the log file rotates, rsyslog stops sending data to the remote server. I tried reloading rsyslog, sending a HUP signal and restarting it altogether, but nothing worked. The only ways I could find that actually worked were dirty: stop the service, delete the rsyslog stat files and start rsyslog again. All that in a postrotate hook in my logrotate file. kill -9 rsyslog and start it over. Is there a proper way for me to do this without touching rsyslog internals? Rsyslog file $ModLoad immark $ModLoad imudp $ModLoad imtcp $ModLoad imuxsock $ModLoad imklog $ModLoad imfile $template WithoutTimeFormat,"[environment] [%syslogtag%] -- %msg%" $WorkDirectory /var/spool/rsyslog $InputFileName /home/user/my_app/shared/log/unicorn.stderr.log $InputFileTag unicorn-stderr $InputFileStateFile stat-unicorn-stderr $InputFileSeverity info $InputFileFacility local8 $InputFilePollInterval 1 $InputFilePersistStateInterval 1 $InputRunFileMonitor # Forward to remote server if $syslogtag contains 'apache-' then @@my_server:5000;WithoutTimeFormat :syslogtag, contains, "apache-" ~ *.* @@my_server:5000;SyslFormat Logrotate file /home/user/shared/log/*.log { daily missingok dateext rotate 30 compress notifempty extension gz copytruncate create 640 user user sharedscripts post-rotate (stop rsyslog && rm /var/spool/rsyslog/stat-* && start rsyslog 2&1) || true endscript } FYI, the file is readable for the rsyslog user, my server is reachable and other log files which do not rotate on the same cycle continue to be tracked properly. I'm running Ubuntu 12.04.

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• PostgreSQL 8.4 - Tablespace Optimization

  - by FloE

  I'm currently running a PostgreSQL Database with about 1.5 billion rows / 500 GB of data (including indices). There are several schemata: on for the (read only, irregular changes / updates) 'core-model' and one for every user (about 20 persons). The users can access the core and store data in their own schema, so everything is located in one database. The server runs with CentOS and PostgreSQL 8.4 and is used for scientific studies, exploration etc and is running quite well. These days an upgrade of the DB storage hard disks arrive - all with the same performance as the old ones. I'm looking for the best way to distribute the data on these disks. It would be possible to separate frequently used objects (the core-data) from the user schemata, but I'm not sure if this is really worth the effort. It seems to be a much better idea to move the WAL files (pg_xlog directory) to its own partition. http://www.postgresql.org/docs/8.4/static/wal-internals.html What are your opinions? Are there any tablespace- or partitioning-related performance documentations / benchmarks?

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• Windows Server NTFS volume list file name encodings and any illegal file names

  - by benbradley

  I'm having to deal with a Windows Server (NTFS) file server and our backup application appears to be failing with certain files. According to this https://en.wikipedia.org/wiki/NTFS#Internals NTFS apparently supports file names encoded in UTF-16 but according to their support team, our backup application only supports UTF-8. I'd like to confirm whether this is actually the problem by seeing the file name encoding for myself. The files that are failing appear to be using plain English A-Z letters and other ASCII characters. No accents or non-English letters etc. I suppose even though the letters appear to be plain A-Z the file name could still be encoded in UTF-16. Does anyone know of a utility or script that can recursively go through all files in a directory and show the encoding of the file name? Then I could try renaming to UTF-8 to see if the backup can proceed. I'm not a Windows developer so can't write this up myself. Presumably the encoding of the file name should be stored in the FS somewhere and therefore it should be possible to expose this.

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• "Security Warning" comes up when I run via another program

  - by Alexander Bird

  If I execute vmmap from the command line it works fine. However, if I call some other program and pass vmmap as a paramater for this other program to start the execution, then I get this "security error" popup -- which makes it hard to automate scripts. In other words, I want to wrap vmmap via another program. In my case, I want to wrap vmmap via another program because whenever vmmap runs, it will bring a window up momentarily and then disappear. So I try passing vmmap as an argument to another program which will start the program "headlessly". I tried this program and this program, and in both cases I get the same popup which defeats the purpose of automation. Why does this happen when the program isn't run directly? Does anyone know the internals of what this warning is? And, utlimately, is there a way to stop this from happening, but only for this instance? I don't want to disable this warning-system on my whole computer. EDIT: I am using Windows Server 2003, and I don't necessarily need solutions for other platforms, but I would like to know what they are if they are platform-dependent solutions.

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• What is the proper way of debugging a slow Windows installation?

  - by Niklas

  You know the drill - you've been asked to check why you cousin's computer is running slow. I was there yesterday. Being a Mac user since 2007 I haven't really dug deep in Windows internals in the past five years. Googling for answers reveals many, many different answers: broken registry, spyware, antivirus program, fragmented disk, turning of visual effects etc. In this particular case I was asked to look at a two year old HP laptop with Vista. Windows was running incredibly slow and even opening up a new explorer window took almost a minute. I ended up doing everything of the above: running cc cleaner, defragmenting the disk, turning off visual effects, turning off norton and a bunch of other things people believe have an impact on Windows performance. Now I'd like to understand this in depth. Is there a proper, "scientific" if you so will, way of debugging and understanding where the problem with a slow running Windows installation lies? (In my particular case this concerned Windows Vista but let's try to create general guide for XP and Windows 7 too). To me, it seems wrong to just run a bunch of different tools without understanding the underlying cause of the error.

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• To what extent is size a factor in SSD performance?

  - by artif

  To what extent is the size of an SSD a factor in its performance? In my mind, correct me if I'm wrong, a bigger SSD should be, everything else being equal, faster than a smaller one. A bigger SSD would have more erase blocks and thus more leeway for the FTL (flash translation layer) to do garbage collection optimization. Also there would be more time before TRIM became necessary. I see on Wikipedia that it remarks that "The performance of the SSD can scale with the number of parallel NAND flash chips used in the device" so it seems throughput also increases significantly. Also many SSDs contain internal caches of some sort and presumably those caches are larger for correspondingly large SSDs. But supposing this effect exists, I would like a quantitative analysis. Does throughput increase linearly? How much is garbage collection impacted, if at all? Does latency stay the same? And so on. Would the performance of a 8 GB SSD be significantly different from, for example, an 80 GB SSD assuming both used high quality chips, controllers, etc? Are there any resources (webpages, research papers, presentations, books, etc) that discuss correlations between SSD performance (4 KB random write speed, latency, maximum sequential throughput, etc) and size? I realize this does not really sound like a programming question but it is relevant for what I'm working on (using flash for caching hard drive data) which does involve programming. If there is a better place to ask this question, eg a more hardware oriented site, what would that be? Something like the equivalent of stack overflow (or perhaps a forum) for in-depth questions on hardware interfaces, internals, etc would be appreciated.

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• Why did you start with Linux ? And why did you continue using it ?

  - by Stefano Borini

  I'd like to know the reasons that moved you towards Linux. Personally, I started because we had to use a Digital for the Fortran 77 exercises during my first year at the university. Linux was installed on many university computers, and I got interested in it. I always liked to code (on the C64) in basic and assembler, but I knew nothing about other languages. I soon discovered a chat engine called NUTS, and the idea of becoming proficient in C appealed me, so I started hacking the code. To do so, I needed a Unix at home, so I bought a Slackware 3.4 and installed it on my Pentium 166. I then continued using it for many years, reason being that I had pleasure in learning new things and the openness of information about the internals. It was a great learning platform. I then moved to osx because I enjoy the power of Unix with the beauty and efficiency of its interface. I am interested in your answer because I believe that the panorama has changed somehow. Although I still guess to find many "hackers" interested in Linux for the sake of knowledge, I also believe that there are other reasons (work, friends, bought a netbook).

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• Installing a new Motherboard in a HP xw6200 case

  - by thing2k

  I have a HP xw6200 Workstation, that is rather long in the tooth, and with 2 physical CPUs, it is quite inefficient. So, the plan was to upgrade the internals. Nothing special: AMD Athlon II X4 640 ASUS M4A78KT-M LE (mATX) 2x 2GB DDR3 1333MHz RAM. 3p under my £150 budget The issues: The pin connector for the front panel isn't a good fit, but I can trim it to size. The PSU has a 8-Pin Power connector, unsurprisingly, the new board has a 4 pin socket. The pins do line up, but I would have to cut it in half to fit. Finally, due to the weight of heat-sinks, they are screwed directly into the case. It turns out that these screws also lock the motherboard in place. As to remove it, you remove the heat-sinks, slide the motherboard across and lift it out. I tested the new board for fit, and while it slots in fine, it's not secure. There is nowhere to screw the board down, it is just held in place with plastic standoffs. The only idea I had, was to wedging something between the side of the motherboard and part of the case. Any suggestions?

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• SQL SERVER – Introduction to Extended Events – Finding Long Running Queries

  - by pinaldave

  The job of an SQL Consultant is very interesting as always. The month before, I was busy doing query optimization and performance tuning projects for our clients, and this month, I am busy delivering my performance in Microsoft SQL Server 2005/2008 Query Optimization and & Performance Tuning Course. I recently read white paper about Extended Event by SQL Server MVP Jonathan Kehayias. You can read the white paper here: Using SQL Server 2008 Extended Events. I also read another appealing chapter by Jonathan in the book, SQLAuthority Book Review – Professional SQL Server 2008 Internals and Troubleshooting. After reading these excellent notes by Jonathan, I decided to upgrade my course and include Extended Event as one of the modules. This week, I have delivered Extended Events session two times and attendees really liked the said course. They really think Extended Events is one of the most powerful tools available. Extended Events can do many things. I suggest that you read the white paper I mentioned to learn more about this tool. Instead of writing a long theory, I am going to write a very quick script for Extended Events. This event session captures all the longest running queries ever since the event session was started. One of the many advantages of the Extended Events is that it can be configured very easily and it is a robust method to collect necessary information in terms of troubleshooting. There are many targets where you can store the information, which include XML file target, which I really like. In the following Events, we are writing the details of the event at two locations: 1) Ringer Buffer; and 2) XML file. It is not necessary to write at both places, either of the two will do. -- Extended Event for finding *long running query* IF EXISTS(SELECT * FROM sys.server_event_sessions WHERE name='LongRunningQuery') DROP EVENT SESSION LongRunningQuery ON SERVER GO -- Create Event CREATE EVENT SESSION LongRunningQuery ON SERVER -- Add event to capture event ADD EVENT sqlserver.sql_statement_completed ( -- Add action - event property ACTION (sqlserver.sql_text, sqlserver.tsql_stack) -- Predicate - time 1000 milisecond WHERE sqlserver.sql_statement_completed.duration > 1000 ) -- Add target for capturing the data - XML File ADD TARGET package0.asynchronous_file_target( SET filename='c:\LongRunningQuery.xet', metadatafile='c:\LongRunningQuery.xem'), -- Add target for capturing the data - Ring Bugger ADD TARGET package0.ring_buffer (SET max_memory = 4096) WITH (max_dispatch_latency = 1 seconds) GO -- Enable Event ALTER EVENT SESSION LongRunningQuery ON SERVER STATE=START GO -- Run long query (longer than 1000 ms) SELECT * FROM AdventureWorks.Sales.SalesOrderDetail ORDER BY UnitPriceDiscount DESC GO -- Stop the event ALTER EVENT SESSION LongRunningQuery ON SERVER STATE=STOP GO -- Read the data from Ring Buffer SELECT CAST(dt.target_data AS XML) AS xmlLockData FROM sys.dm_xe_session_targets dt JOIN sys.dm_xe_sessions ds ON ds.Address = dt.event_session_address JOIN sys.server_event_sessions ss ON ds.Name = ss.Name WHERE dt.target_name = 'ring_buffer' AND ds.Name = 'LongRunningQuery' GO -- Read the data from XML File SELECT event_data_XML.value('(event/data[1])[1]','VARCHAR(100)') AS Database_ID, event_data_XML.value('(event/data[2])[1]','INT') AS OBJECT_ID, event_data_XML.value('(event/data[3])[1]','INT') AS object_type, event_data_XML.value('(event/data[4])[1]','INT') AS cpu, event_data_XML.value('(event/data[5])[1]','INT') AS duration, event_data_XML.value('(event/data[6])[1]','INT') AS reads, event_data_XML.value('(event/data[7])[1]','INT') AS writes, event_data_XML.value('(event/action[1])[1]','VARCHAR(512)') AS sql_text, event_data_XML.value('(event/action[2])[1]','VARCHAR(512)') AS tsql_stack, CAST(event_data_XML.value('(event/action[2])[1]','VARCHAR(512)') AS XML).value('(frame/@handle)[1]','VARCHAR(50)') AS handle FROM ( SELECT CAST(event_data AS XML) event_data_XML, * FROM sys.fn_xe_file_target_read_file ('c:\LongRunningQuery*.xet', 'c:\LongRunningQuery*.xem', NULL, NULL)) T GO -- Clean up. Drop the event DROP EVENT SESSION LongRunningQuery ON SERVER GO Just run the above query, afterwards you will find following result set. This result set contains the query that was running over 1000 ms. In our example, I used the XML file, and it does not reset when SQL services or computers restarts (if you are using DMV, it will reset when SQL services restarts). This event session can be very helpful for troubleshooting. Let me know if you want me to write more about Extended Events. I am totally fascinated with this feature, so I’m planning to acquire more knowledge about it so I can determine its other usages. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Training, SQLServer, T SQL, Technology Tagged: SQL Extended Events

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• SQL SERVER – Video – Beginning Performance Tuning with SQL Server Execution Plan

  - by pinaldave

  Traveling can be most interesting or most exhausting experience. However, traveling is always the most enlightening experience one can have. While going to long journey one has to prepare a lot of things. Pack necessary travel gears, clothes and medicines. However, the most essential part of travel is the journey to the destination. There are many variations one prefer but the ultimate goal is to have a delightful experience during the journey. Here is the video available which explains how to begin with SQL Server Execution plans. Performance Tuning is a Journey Performance tuning is just like a long journey. The goal of performance tuning is efficient and least resources consuming query execution with accurate results. Just as maps are the most essential aspect of performance tuning the same way, execution plans are essentially maps for SQL Server to reach to the resultset. The goal of the execution plan is to find the most efficient path which translates the least usage of the resources (CPU, memory, IO etc). Execution Plans are like Maps When online maps were invented (e.g. Bing, Google, Mapquests etc) initially it was not possible to customize them. They were given a single route to reach to the destination. As time evolved now it is possible to give various hints to the maps, for example ‘via public transport’, ‘walking’, ‘fastest route’, ‘shortest route’, ‘avoid highway’. There are places where we manually drag the route and make it appropriate to our needs. The same situation is with SQL Server Execution Plans, if we want to tune the queries, we need to understand the execution plans and execution plans internals. We need to understand the smallest details which relate to execution plan when we our destination is optimal queries. Understanding Execution Plans The biggest challenge with maps are figuring out the optimal path. The same way the  most common challenge with execution plans is where to start from and which precise route to take. Here is a quick list of the frequently asked questions related to execution plans: Should I read the execution plans from bottoms up or top down? Is execution plans are left to right or right to left? What is the relational between actual execution plan and estimated execution plan? When I mouse over operator I see CPU and IO but not memory, why? Sometime I ran the query multiple times and I get different execution plan, why? How to cache the query execution plan and data? I created an optimal index but the query is not using it. What should I change – query, index or provide hints? What are the tools available which helps quickly to debug performance problems? Etc… Honestly the list is quite a big and humanly impossible to write everything in the words. SQL Server Performance:  Introduction to Query Tuning My friend Vinod Kumar and I have created for the same a video learning course for beginning performance tuning. We have covered plethora of the subject in the course. Here is the quick list of the same: Execution Plan Basics Essential Indexing Techniques Query Design for Performance Performance Tuning Tools Tips and Tricks Checklist: Performance Tuning We believe we have covered a lot in this four hour course and we encourage you to go over the video course if you are interested in Beginning SQL Server Performance Tuning and Query Tuning. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video Tagged: Execution Plan

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• Clean Code: A Handbook of Agile Software Craftsmanship – book review

  - by DigiMortal

     Writing code that is easy read and test is not something that is easy to achieve. Unfortunately there are still way too much programming students who write awful spaghetti after graduating. But there is one really good book that helps you raise your code to new level – your code will be also communication tool for you and your fellow programmers. “Clean Code: A Handbook of Agile Software Craftsmanship” by Robert C. Martin is excellent book that helps you start writing the easily readable code. Of course, you are the one who has to learn and practice but using this book you have very good guide that keeps you going to right direction. You can start writing better code while you read this book and you can do it right in your current projects – you don’t have to create new guestbook or some other simple application to start practicing. Take the project you are working on and start making it better! My special thanks to Robert C. Martin I want to say my special thanks to Robert C. Martin for this book. There are many books that teach you different stuff and usually you have markable learning curve to go before you start getting results. There are many books that show you the direction to go and then leave you alone figuring out how to achieve all that stuff you just read about. Clean Code gives you a lot more – the mental tools to use so you can go your way to clean code being sure you will be soon there. I am reading books as much as I have time for it. Clean Code is top-level book for developers who have to write working code. Before anything else take Clean Code and read it. You will never regret your decision. I promise. Fragment of editorial review “Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees. Every year, countless hours and significant resources are lost because of poorly written code. But it doesn’t have to be that way. What kind of work will you be doing? You’ll be reading code—lots of code. And you will be challenged to think about what’s right about that code, and what’s wrong with it. More importantly, you will be challenged to reassess your professional values and your commitment to your craft. Readers will come away from this book understanding How to tell the difference between good and bad code How to write good code and how to transform bad code into good code How to create good names, good functions, good objects, and good classes How to format code for maximum readability How to implement complete error handling without obscuring code logic How to unit test and practice test-driven development This book is a must for any developer, software engineer, project manager, team lead, or systems analyst with an interest in producing better code.” Table of contents Clean code Meaningful names Functions Comments Formatting Objects and data structures Error handling Boundaries Unit tests Classes Systems Emergence Concurrency Successive refinement JUnit internals Refactoring SerialDate Smells and heuristics A Concurrency II org.jfree.date.SerialDate Cross references of heuristics Epilogue Index

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