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  • Aren't Information Expert / Tell Don't Ask at odds with Single Responsibility Principle?

    - by moffdub
    It is probably just me, which is why I'm asking the question. Information Expert, Tell Don't Ask, and SRP are often mentioned together as best practices. But I think they are at odds. Here is what I'm talking about: Code that favors SRP but violates Tell Don't Ask, Info Expert: Customer bob = ...; // TransferObjectFactory has to use Customer's accessors to do its work, // violates Tell Don't Ask CustomerDTO dto = TransferObjectFactory.createFrom(bob); Code that favors Tell Don't Ask / Info Expert but violates SRP: Customer bob = ...; // Now Customer is doing more than just representing the domain concept of Customer, // violates SRP CustomerDTO dto = bob.toDTO(); If they are indeed at odds, that's a vindication of my OCD. Otherwise, please fill me in on how these practices can co-exist peacefully. Thank you. Edit: someone wants a definition of the terms - Information Expert: objects that have the data needed for the operation should host the operation Tell Don't Ask: don't ask objects for data in order to do work; tell the objects to do the work Single Responsibility Principle: each object should have a narrowly defined responsibility

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  • How to set ExportMetaData with multiple values as well as single w/ custom attribute ?

    - by Matthew M.
    I have the following ExportMetaData attributes set on my class: [Export(typeof(IDocumentViewer))] [ExportMetadata("Name", "MyViewer")] [ExportMetadata("SupportsEditing", true)] [ExportMetadata("Formats", DocFormat.DOC, IsMultiple = true)] [ExportMetadata("Formats", DocFormat.DOCX, IsMultiple = true)] [ExportMetadata("Formats", DocFormat.RTF, IsMultiple = true)] I also have a supporting interface: public interface IDocumentViewerMetaData { /// <summary> /// Gets the format. /// </summary> /// <value>The format.</value> IEnumerable<DocFormat> Formats { get; } /// <summary> /// Gets the name of the viewer /// </summary> /// <value>The name.</value> string Name { get; } /// <summary> /// Gets a value indicating whether this viewer supports editing /// </summary> /// <value><c>true</c> if [supports editing]; otherwise, <c>false</c>.</value> bool SupportsEditing { get; } } And of course my ImportMany: [ImportMany(typeof(IDocumentViewer))] public IEnumerable<Lazy<IDocumentViewer, IDocumentViewerMetaData>> _viewers { get; set; } What I would like to do is use a strongly-typed attribute class instead of using the ExportMetaData attribute. I have not figured out a way to do this while also supporting single values (Name, SupportsEditing, in the example above). I envision doing something similiar the following (or whatever is suggested as best): [Export(typeof(IDocumentViewer))] [DocumentViewerMetadata(Name = "MyViewer")] [DocumentViewerMetadata(SupportsEditing = true)] [DocumentViewerMetadata(Format = DocFormat.DOC)] [DocumentViewerMetadata(Format = DocFormat.DOCX)] I am fairly certain that there IS a way to do this, I just haven't found the right way to connect the dots. :) Thank you, Matthew

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  • What's the largest (most complex) PHP algorithm ever implemented in a single monolithic PHP script?

    - by Alex R
    I'm working on a tool which converts PHP code to Scala. As one of the finishing touches, I'm in need of a really good (er, somewhat biased) benchmark. By dumb luck my first benchmark attempt was with some code which uses bcmath extensively, which unfortunately is 1000x slower in Java, making the Scala code 22x slower overall than the original PHP. So I'm looking for some meaningful PHP benchmark with the following characteristics: The source needs to be in a single file. I need it to be simple to setup - no databases, hard-to-find input files, etc. Simple text input and output preferred. It should not use features that are slow in Java (BigInteger, trigonometric functions, etc). It should not use exoteric or dynamic PHP functions (e.g. no "eval" or "variable vars"). It should not over-rely on built-in libraries, e.g. MD5, crypt, etc. It should not be I/O bound. A CPU-bound memory-hungry algorithm is preferred. Basically, intensive OO operations, integer and string manipulation, recursion, etc would be great. Thanks

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  • How to set up single array or dictionary for use in multiple datasources?

    - by Roman
    I have multiple TableViewDatasources that need to display list of objects form same pool depending of certain property. E.g. object.flag1 is set- it will show up in TableView1 object.flag2 is set- it will show up in TableView2 The obvious way would be to have separate arrays for each TableView, But same object may appear in different arrays. Also I need to update objects very often or access all objects through same array. How do I setup a single dictionary or array to have all objects in one structure? To put it in another way: When table view or selection changes, application need to redraw TableViews with the new data. Application have to access the pool of objects and search through them using iterator and accessing each object and its properties. I think that this is an expensive operation and want to avoid that. Perhaps maybe by making a global pool of objects a dictionary and exposing objects properties as dictionary fields. So instead of iterating global pool of objects I could access global pool Dicitonary in a manner of database by selecting objects that has fields that match particular criteria. Anyone know any example of doing that?

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  • Is it possible to declare multiple static variable with same name in a single C file?

    - by Mohammed Khalid Kherani
    Hi Experts, Is it possible to declare multiple static variables of same name in a single C file with different scopes? I wrote a simple programme to check this and in gcc it got compiled and worked fine. code: static int sVar = 44; void myPrint2() { printf("sVar = %d\n", sVar++); } void myPrint() { static int sVar =88; printf("sVar = %d\n", sVar++); } int main(void) { static int sVar = 55; int i = 0; for (i = 0; i < 5; i++) myPrint(); printf("sVar = %d\n", sVar); myPrint2(); return(0); } Now my question is since all "static" variable will reside in same section (.data) then how we can have multiple variable with same name in one section? I used objdump to check the different section and found that all Static variables (sVar) were in .data section but with different names 0804960c l O .data 00000004 sVar 08049610 l O .data 00000004 sVar.1785 08049614 l O .data 00000004 sVar.1792 Why compiler is changing the name of variables (since C doesnt support name mangling)? Thanks in advance.

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  • How do I construct a more complex single LINQ to XML query?

    - by Cyberherbalist
    I'm a LINQ newbie, so the following might turn out to be very simple and obvious once it's answered, but I have to admit that the question is kicking my arse. Given this XML: <measuresystems> <measuresystem name="SI" attitude="proud"> <dimension name="mass" dim="M" degree="1"> <unit name="kilogram" symbol="kg"> <factor name="hundredweight" foreignsystem="US" value="45.359237" /> <factor name="hundredweight" foreignsystem="Imperial" value="50.80234544" /> </unit> </dimension> </measuresystem> </measuresystems> I can query for the value of the conversion factor between kilogram and US hundredweight using the following LINQ to XML, but surely there is a way to condense the four successive queries into a single complex query? XElement mss = XElement.Load(fileName); IEnumerable<XElement> ms = from el in mss.Elements("measuresystem") where (string)el.Attribute("name") == "SI" select el; IEnumerable<XElement> dim = from e2 in ms.Elements("dimension") where (string)e2.Attribute("name") == "mass" select e2; IEnumerable<XElement> unit = from e3 in dim.Elements("unit") where (string)e3.Attribute("name") == "kilogram" select e3; IEnumerable<XElement> factor = from e4 in unit.Elements("factor") where (string)e4.Attribute("name") == "pound" && (string)e4.Attribute("foreignsystem") == "US" select e4; foreach (XElement ex in factor) { Console.WriteLine ((string)ex.Attribute("value")); }

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  • How would I find all sets of N single-digit, non-repeating numbers that add up to a given sum in PHP

    - by TerranRich
    Let's say I want to find all sets of 5 single-digit, non-repeating numbers that add up to 30... I'd end up with [9,8,7,5,1], [9,8,7,4,2], [9,8,6,4,3], [9,8,6,5,2], [9,7,6,5,3], and [8,7,6,5,4]. Each of those sets contains 5 non-repeating digits that add up to 30, the given sum. Any help would be greatly appreciated. Even just a starting point for me to use would be awesome. I came up with one method, which seems like a long way of going about it: get all unique 5-digit numbers (12345, 12346, 12347, etc.), add up the digits, and see if it equals the given sum (e.g. 30). If it does, add it to the list of possible matching sets. I'm doing this for a personal project, which will help me in solving Kakuro puzzles without actually solving the whole thing at once. Yeah, it may be cheating, but it's... it's not THAT bad... :P

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  • How to cope with null results in SQL Tasks that return single rows in SSIS 2005?

    - by JSacksteder
    In a dataflow task, I can slip a rowcount into the processing flow and place the count into a variable. I can later use that variable to conditionally perform some other work if the rowcount was 0. This works well for me, but I have no corresponding strategy for sql tasks expected to return a single row. In that event, I'm returning those values into variables. If the lookup produces no rows, the sql task fails when assigning values into those variables. I can branch on that component failing, but there's a side effect of that - if I'm running the job as a SQL server agent job step, the step returns DTSER_FAILURE, causing the step to fail. I can tell the sql agent to disregard the step failure, but then I won't know if I have a legitimate error in that step. This seems harder than it should be. The only strategy I can think of is to run the same query with a count(*) aggregate and test if that returns a number 0 and if so running the query again without the count. That's ugly because I have the same query in two places that I need to keep in sync. Is there a better way?

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  • Fetch Data using predicate. Retrieve single value.

    - by Mr. McPepperNuts
    XYZAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate]; NSManagedObjectContext *managedObjectContext = appDelegate.managedObjectContext; NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name == %@", entryToSearchFor]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Entry" inManagedObjectContext:managedObjectContext]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [request setSortDescriptors:sortDescriptors]; [request setEntity: entity]; [request setPredicate: predicate]; NSArray *results = [managedObjectContext executeFetchRequest:request error:nil]; if (results == nil) { NSLog(@"No results found"); }else { NSLog(@"entryToSearchFor %@", entryToSearchFor); NSLog(@"results %@", [results objectAtIndex:0]); } I want to retrieve a single value (String) from "Entry." I believe I must be missing. Can someone point it out? Btw, the NSLog results outputs the following: results <NSManagedObject: 0x3d2d360> (entity: Entry; id: 0x3d13650 <x-coredata://6EA12ADA-8C0B-477F-801C-B44FE6E6C91C/Entry/p3> ; data: <fault>)

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  • What is an efficient strategy for multiple threads posting jobs and waiting for response from a single thread?

    - by jakewins
    In java, what is an efficient solution to the following problem: I have multiple threads (10-20 or so) generating jobs ("Job Creators"), and a single thread capable of performing them ("The worker"). Once a job creator has posted a job, it should wait for the job to finish, yielding no result other than "it's done", before it keeps going. For sending the jobs to the worker thread, I think a ring buffer or similar standard fan-in setup would perhaps be a good approach? But for a Job Creator to find out that her job has been done, I'm not so sure.. The job creators could sleep, and the worker interrupt them when done.. Or each job creator could have an atomic boolean that it checks, and that the worker sets. I dunno, neither of those feel very nice. I'd like to do it with as few (none, if possible) locks as absolutely possible. So to be clear: What I'm looking for is speed, not necessarily simplicity. Does anyone have any suggestions? Links to reading about concurrency strategies would also be very welcome!

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  • How to change the css class="current" when using page jumping (single page website)?

    - by Bryan
    Morning, I must be asking google all the wrong questions, because I can't find anything similar. I have a standard navigation list, but I'm using page jumping because I wanted a single web page. <ul> <li><a href="#livestream">Livestream</a></li> <li><a href="#media">Media</a></li> <li><a href="#crew">Crew</a></li> <li><a href="#services">Services</a></li> <li><a href="#contact">Contact</a></li> </ul> But I can't for the life of me figure out how to make the class="current" when using page jumping. I've tried this bit of jquery because it appears to be what I'm looking for, but it did nothing. I don't think it'll work for #links. Any ideas?

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  • Is it possible for two VS2008 C# class library projects to share a single namespace?

    - by jeah
    I am trying to share a common namespace between two projects in a single solution. The projects are "Blueprint" and "Repositories". Blueprint contains Interfaces for the entire application and serves as a reference for the application structure. In the Blueprint project, I have an interface with the following declaration: namespace Application.Repositories{ public interface IRepository{ IEntity Get(Guid id); } } In the Repositories project I have a class the following class: namespace Application.Repositories{ public class STDRepository: IRepository { STD Get(Guid id){ return new SkankyExGirlfriendDataContext() .FirstOrDefault<STD>(x=>x.DiseaseId == id); } } } However, this does not work. The Repositories project has a reference to the Blueprint project. I receive a VS error: "The type or namespace name 'IRepository' could not be found (are you missing a using directive or an assembly reference?) - Normally, this is easy to fix but adding a using statement doesn't make sense since they have the same namespace. I tried it anyway and it didn't work. The reference has been added, and without the line of code referencing that interface, both projects compile successfully. I am lost here. I have searched all over and have found nothing, so I am assuming that there is something fundamentally wrong with what I'm doing ... but I don't know what it is. So, I would appreciate some explanation or guidance as to how to fix this problem. I hope you guys can help. Note: The reason I want to do it this way and keep the interfaces under the same namespace is because I want a solid project to keep all the interfaces in, in order to have a reference for the full architecture of the application. I have considered work arounds, such as putting all of the interfaces in the Blueprint.Application namespace instead of the application namespace. However, that would require me to write the using statement on virtually every page in the application...and my fingers get tired. Thanks again guys...

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  • Structuring the UI code of a single-page EXTjs Web app using Rails?

    - by Daniel Beardsley
    I’m in the process of creating a large single-page web-app using ext-js for the UI components with Rails on the backend. I’ve come to good solutions for transferring data using Whorm gem and Rails support of RESTful Resources. What I haven’t come to a conclusion on is how to structure the UI and business logic aspects of the application. I’ve had a look at a few options, including Netzke but haven’t seen anything that I really think fits my needs. How should a web-application that uses ext-js components, layouts, and controls in the browser and Rails on the server best implement UI component re-use, good organization, and maintainability while maintaining a flexible layout design. Specifically I’m looking for best-practice suggestions for structuring the code that creates and configures UI components (many UI config options will be based on user data) Should EXT classes be extended in static JS for often re-used customizations and then instantiated with various configuration options by generated JS within html partials? Should partials create javascript blocks that instantiate EXT components? Should partials call helpers that return ruby hashes for EXT component config which is then dumped to Json? Something else entirely? There are many options and I'd love to hear from people who've been down this road and found some methodology that worked for them.

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  • How create single HTML file to viewed in Excel with multiple sheets?

    - by Dmitry Nelepov
    I want know, is it possible create single HTML file wich (after chaging extension to xls) when opened at Excel will parsed to multiple sheets. Little example i got file test.xls with contents <html> <body> <table> <tr> <td> 1 </td> <td> 2 </td> <td> 3 </td> <td> =sum(A1:C1) </td> </tr> </table> </body> </html> When i open this file at Excel i got one Sheet with calculated sum of cells A1 to C1 in A4=6 I wonder, it's possible create a HTML file wich containts multiple tables wich will be parsed as multiple sheets at Excel. Here Excel view of this file

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  • best practices question: How to save a collection of images and a java object in a single file? File

    - by Richard
    Hi all, I am making a java program that has a collection of flash-card like objects. I store the objects in a jtree composed of defaultmutabletreenodes. Each node has a user object attached to it with has a few string/native data type parameters. However, i also want each of these objects to have an image (typical formats, jpg, png etc). I would like to be able to store all of this information, including the images and the tree data to the disk in a single file so the file can be transferred between users and the entire tree, including the images and parameters for each object, can be reconstructed. I had not approached a problem like this before so I was not sure what the best practices were. I found XLMEncoder (http://java.sun.com/j2se/1.4.2/docs/api/java/beans/XMLEncoder.html) to be a very effective way of storing my tree and the native data type information. However I couldn't figure out how to save the image data itself inside of the XML file, and I'm not sure it is possible since the data is binary (so restricted characters would be invalid). My next thought was to associate a hash string instead of an image within each user object, and then gzip together all of the images, with the hash strings as the names and the XMLencoded tree in the same compmressed file. That seemed really contrived though. Does anyone know a good approach for this type of issue? THanks! Thanks!

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  • Subquery with multiple results combined into a single field?

    - by Todd
    Assume I have these tables, from which i need to display search results in a browser: Table: Containers id | name 1 Big Box 2 Grocery Bag 3 Envelope 4 Zip Lock Table: Sale id | date | containerid 1 20100101 1 2 20100102 2 3 20091201 3 4 20091115 4 Table: Items id | name | saleid 1 Barbie Doll 1 2 Coin 3 3 Pop-Top 4 4 Barbie Doll 2 5 Coin 4 I need output that looks like this: itemid itemname saleids saledates containerids containertypes 1 Barbie Doll 1,2 20100101,20100102 1,2 Big Box, Grocery Bag 2 Coin 3,4 20091201,20091115 3,4 Envelope, Zip Lock 3 Pop-Top 4 20091115 4 Zip Lock The important part is that each item type only gets one record/row in the return on the screen. I accomplished this in the past by returning multiple rows of the same item and using a scripting language to limit the output. However, this makes the ui overly complicated and loopy. So, I'm hoping I can get the database to spit out only as many records as there are rows to display. This example may be a bit extreme because of the 2 joins needed to get to the container from the item (through the sale table). I'd be happy for just an example query that outputs this: itemid itemname saleids saledates 1 Barbie Doll 1,2 20100101,20100102 2 Coin 3,4 20091201,20091115 3 Pop-Top 4 20091115 I can only return a single result in a subquery, so I'm not sure how to do this.

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  • RIA Service/oData ... "Requests that attempt to access a single element using key values from a resu

    - by user327911
    I've recently started working up a sample project to play with an oData feed coming from a RIA service. I am able to view the feed and the metadata via any web browser, however, if I try to perform certain query operations on the feed I receive "unsupported" exceptions. Sample oData feed: ProductSet http://localhost:50880/Services/Rebirth-Web-Services-ProductService.svc/OData/ProductSet/ 2010-04-28T14:02:10Z http://localhost:50880/Services/Rebirth-Web-Services-ProductService.svc/OData/ProductSet(guid'b0a2b170-c6df-441f-ae2a-74dd19901128') 2010-04-28T14:02:10Z b0a2b170-c6df-441f-ae2a-74dd19901128 Product 0 Type 1 Active Sample web.config entry: Sample service: [EnableClientAccess()] public class ProductService : DomainService { [Query(IsDefault = true)] public IQueryable GetProducts() { IList products = new List(); for (int i = 0; i < 90; i++) { Product product = new Product { Id = Guid.NewGuid(), Name = "Product " + i.ToString(), ProductType = i < 30 ? "Type 1" : ((i > 30 && i < 60) ? "Type 2" : "Type 3"), Status = i % 2 == 0 ? "Active" : "NotActive" }; products.Add(product); } return products.AsQueryable(); } } If I provide the url "http://localhost:50880/Services/Rebirth-Web-Services-ProductService.svc/OData/ProductSet(guid'b0a2b170-c6df-441f-ae2a-74dd19901128')" to my web browser I receive the following xml: Requests that attempt to access a single element using key values from a result set are not supported. I'm new to RIA and oData. Could this be something as simple as my web browsers not supporting this type of querying on the result set or something else? Thanks ahead! Corey

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  • How do I gather data from the same collumn in multiple worksheets in a single workbook?

    - by infiniteloop91
    Okay so here is what I want to accomplish. For this example I have a single workbook composed of 4 data sheets plus a totals sheet. Each of the 4 data sheets has a similar name following the same pattern where the only difference is the date. (Ex. 9854978_1009_US.txt, where 1009 is the date that changes while the rest of the file name is the same). In each of those documents column F contains a series of number that I would like to find the sum of but I will have no idea how many cells in F actually contain numbers. (However there will never be additional information below it the numbers so I could in theory just add the entire F column together). I will also add new files to the workbook over time and do not want to have to rewrite the code of which I gather my data from column F. Essentially what I would like to accomplish is for the 'totals' document to take every column F from documents in the workbook with the name of '9854978_????_US.txt', where the question marks change based on the file name. How would I go about doing this in pure Excel code?

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  • PHP Arrays: Pop an array of single-element arrays into one array.

    - by Rob Drimmie
    Using a proprietary framework, I am frequently finding myself in the situation where I get a resultset from the database in the following format: array(5) { [0] => array(1) { ["id"] => int(241) } [1] => array(1) { ["id"] => int(2) } [2] => array(1) { ["id"] => int(81) } [3] => array(1) { ["id"] => int(560) } [4] => array(1) { ["id"] => int(10) } } I'd much rather have a single array of ids, such as: array(5) { [0] => int(241) [1] => int(2) [2] => int(81) [3] => int(560) [4] => int(10) } To get there, I frequently find myself writing: $justIds = array(); foreach( $allIds as $id ) { $justIds[] = $id["id"]; } Is there a more efficient way to do this?

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  • How can I have a single helper work on different models passed to it?

    - by Angela
    I am probably going to need to refactor in two steps since I'm still developing the project and learning the use-cases as I go along since it is to scratch my own itch. I have three models: Letters, Calls, Emails. They have some similarilty, but I anticipate they also will have some different attributes as you can tell from their description. Ideally I could refactor them as Events, with a type as Letters, Calls, Emails, but didn't know how to extend subclasses. My immediate need is this: I have a helper which checks on the status of whether an email (for example) was sent to a specific contact: def show_email_status(contact, email) @contact_email = ContactEmail.find(:first, :conditions => {:contact_id => contact.id, :email_id => email.id }) if ! @contact_email.nil? return @contact_email.status end end I realized that I, of course, want to know the status for whether a call was made to a contact as well, so I wrote: def show_call_status(contact, call) @contact_call = ContactCall.find(:first, :conditions => {:contact_id => contact.id, :call_id => call.id }) if ! @contact_call.nil? return @contact_call.status end end I would love to be able to just have a single helper show_status where I can say show_status(contact,call) or show_status(contact,email) and it would know whether to look for the object @contact_call or @contact_email. Yes, it would be easier if it were just @contact_event, but I want to do a small refactoring while I get the program up and running, and this would make the ability to do a history for a given contact much easier. Thanks!

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  • SQL SERVER – SQLServer Quiz 2011 – Do you know your execution plan – Two questions – One Answer

    - by pinaldave
    My friend Jacob Sebastian has SQL Server Quiz 2011 launched. This time when he asked me to come up with quiz question – I wanted to come up with something which is new and make participant to think about it. After carefully thinking I come with question which I really like to solve myself. Here is the details: 1) Using Single table only Once in Single SELECT statement generate execution plan which have JOIN operator. Explain the reason for the same. 2) Using Single table only Once in Single SELECT statement generate execution plan which have parallelism operator. Explain the reason for the same. Bonus: Create a single query which satisfy both of the above statement. To answer this question and win exciting gifts please visit the SQL Server Quiz website. Reference: Pinal Dave (http://blog.SQLAuthority.com)   Filed under: Pinal Dave, PostADay, Readers Contribution, Readers Question, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • Talend Enterprise Data Integration overperforms on Oracle SPARC T4

    - by Amir Javanshir
    The SPARC T microprocessor, released in 2005 by Sun Microsystems, and now continued at Oracle, has a good track record in parallel execution and multi-threaded performance. However it was less suited for pure single-threaded workloads. The new SPARC T4 processor is now filling that gap by offering a 5x better single-thread performance over previous generations. Following our long-term relationship with Talend, a fast growing ISV positioned by Gartner in the “Visionaries” quadrant of the “Magic Quadrant for Data Integration Tools”, we decided to test some of their integration components with the T4 chip, more precisely on a T4-1 system, in order to verify first hand if this new processor stands up to its promises. Several tests were performed, mainly focused on: Single-thread performance of the new SPARC T4 processor compared to an older SPARC T2+ processor Overall throughput of the SPARC T4-1 server using multiple threads The tests consisted in reading large amounts of data --ten's of gigabytes--, processing and writing them back to a file or an Oracle 11gR2 database table. They are CPU, memory and IO bound tests. Given the main focus of this project --CPU performance--, bottlenecks were removed as much as possible on the memory and IO sub-systems. When possible, the data to process was put into the ZFS filesystem cache, for instance. Also, two external storage devices were directly attached to the servers under test, each one divided in two ZFS pools for read and write operations. Multi-thread: Testing throughput on the Oracle T4-1 The tests were performed with different number of simultaneous threads (1, 2, 4, 8, 12, 16, 32, 48 and 64) and using different storage devices: Flash, Fibre Channel storage, two stripped internal disks and one single internal disk. All storage devices used ZFS as filesystem and volume management. Each thread read a dedicated 1GB-large file containing 12.5M lines with the following structure: customerID;FirstName;LastName;StreetAddress;City;State;Zip;Cust_Status;Since_DT;Status_DT 1;Ronald;Reagan;South Highway;Santa Fe;Montana;98756;A;04-06-2006;09-08-2008 2;Theodore;Roosevelt;Timberlane Drive;Columbus;Louisiana;75677;A;10-05-2009;27-05-2008 3;Andrew;Madison;S Rustle St;Santa Fe;Arkansas;75677;A;29-04-2005;09-02-2008 4;Dwight;Adams;South Roosevelt Drive;Baton Rouge;Vermont;75677;A;15-02-2004;26-01-2007 […] The following graphs present the results of our tests: Unsurprisingly up to 16 threads, all files fit in the ZFS cache a.k.a L2ARC : once the cache is hot there is no performance difference depending on the underlying storage. From 16 threads upwards however, it is clear that IO becomes a bottleneck, having a good IO subsystem is thus key. Single-disk performance collapses whereas the Sun F5100 and ST6180 arrays allow the T4-1 to scale quite seamlessly. From 32 to 64 threads, the performance is almost constant with just a slow decline. For the database load tests, only the best IO configuration --using external storage devices-- were used, hosting the Oracle table spaces and redo log files. Using the Sun Storage F5100 array allows the T4-1 server to scale up to 48 parallel JVM processes before saturating the CPU. The final result is a staggering 646K lines per second insertion in an Oracle table using 48 parallel threads. Single-thread: Testing the single thread performance Seven different tests were performed on both servers. Given the fact that only one thread, thus one file was read, no IO bottleneck was involved, all data being served from the ZFS cache. Read File ? Filter ? Write File: Read file, filter data, write the filtered data in a new file. The filter is set on the “Status” column: only lines with status set to “A” are selected. This limits each output file to about 500 MB. Read File ? Load Database Table: Read file, insert into a single Oracle table. Average: Read file, compute the average of a numeric column, write the result in a new file. Division & Square Root: Read file, perform a division and square root on a numeric column, write the result data in a new file. Oracle DB Dump: Dump the content of an Oracle table (12.5M rows) into a CSV file. Transform: Read file, transform, write the result data in a new file. The transformations applied are: set the address column to upper case and add an extra column at the end, which is the concatenation of two columns. Sort: Read file, sort a numeric and alpha numeric column, write the result data in a new file. The following table and graph present the final results of the tests: Throughput unit is thousand lines per second processed (K lines/second). Improvement is the % of improvement between the T5140 and T4-1. Test T4-1 (Time s.) T5140 (Time s.) Improvement T4-1 (Throughput) T5140 (Throughput) Read/Filter/Write 125 806 645% 100 16 Read/Load Database 195 1111 570% 64 11 Average 96 557 580% 130 22 Division & Square Root 161 1054 655% 78 12 Oracle DB Dump 164 945 576% 76 13 Transform 159 1124 707% 79 11 Sort 251 1336 532% 50 9 The improvement of single-thread performance is quite dramatic: depending on the tests, the T4 is between 5.4 to 7 times faster than the T2+. It seems clear that the SPARC T4 processor has gone a long way filling the gap in single-thread performance, without sacrifying the multi-threaded capability as it still shows a very impressive scaling on heavy-duty multi-threaded jobs. Finally, as always at Oracle ISV Engineering, we are happy to help our ISV partners test their own applications on our platforms, so don't hesitate to contact us and let's see what the SPARC T4-based systems can do for your application! "As describe in this benchmark, Talend Enterprise Data Integration has overperformed on T4. I was generally happy to see that the T4 gave scaling opportunities for many scenarios like complex aggregations. Row by row insertion in Oracle DB is faster with more than 650,000 rows per seconds without using any bulk Oracle capabilities !" Cedric Carbone, Talend CTO.

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  • Django custom SQL returning single row of results when query returns 2?

    - by Alvin
    I have a custom SQL call that is returning different results to the template than I get when I run the same query against the database directly, 1 row vs 2 Query - copied from Django Debug Toolbar: SELECT ((Sum(new_recruit_interviews) / Sum(opportunities_offered)) * 100) as avg_recruit, ((Sum(inspections) / Sum(presentations)) * 100) as avg_inspect, ((Sum(contracts_signed) / Sum(roof_approvals)) * 100) as avg_contracts, ((Sum(adjusters) / Sum(contracts_signed)) * 100) as avg_adjusters, ((Sum(roof_approvals) / Sum(adjusters)) *100) as roof_approval_avg, ((Sum(roof_turned_in) / Sum(adjusters)) * 100) as roof_jobs_avg, Sum(roof_turned_in) as roof_jobs_total, ((Sum(siding_approvals) / Sum(adjusters)) *100) as siding_approval_avg, ((Sum(siding_turned_in) / Sum(adjusters)) * 100) as siding_jobs_avg, Sum(siding_turned_in) as siding_jobs_total, ((Sum(gutter_approvals) / Sum(adjusters)) *100) as gutter_approval_avg, ((Sum(gutter_turned_in) / Sum(adjusters)) * 100) as gutter_jobs_avg, Sum(gutter_turned_in) as gutter_jobs_total, ((Sum(window_approvals) / Sum(adjusters)) *100) as window_approval_avg, ((Sum(window_turned_in) / Sum(adjusters)) * 100) as window_jobs_avg, Sum(window_turned_in) as window_jobs_total, (Sum(roof_turned_in) + Sum(siding_turned_in) + Sum(gutter_turned_in) + Sum(window_turned_in)) as total_jobs, (((Sum(collections_jobs_new) + Sum(collections_jobs_previous)) / (Sum(roof_turned_in) + Sum(siding_turned_in) + Sum(gutter_turned_in) + Sum(window_turned_in))) * 100) as total_collections, sales_report_salesmen.location_id as detail_id, business_unit_location.title as title FROM sales_report_salesmen Inner Join auth_user ON sales_report_salesmen.user_id = auth_user.id Inner Join business_unit_location ON sales_report_salesmen.location_id = business_unit_location.id GROUP BY location_id Results from direct query running the above query: INSERT INTO `` (`avg_recruit`, `avg_inspect`, `avg_contracts`, `avg_adjusters`, `roof_approval_avg`, `roof_jobs_avg`, `roof_jobs_total`, `siding_approval_avg`, `siding_jobs_avg`, `siding_jobs_total`, `gutter_approval_avg`, `gutter_jobs_avg`, `gutter_jobs_total`, `window_approval_avg`, `window_jobs_avg`, `window_jobs_total`, `total_jobs`, `total_collections`, `detail_id`, `title`) VALUES (95.3968, 92.8178, 106.9622, 90.2928, 103.5420, 103.5670, 4152, 100.2494, 106.8845, 4285, 120.1297, 86.2559, 3458, 92.9658, 106.1611, 4256, 16151, 4.281469, 12, 'St Paul, MN'); VALUES (90.2982, 73.3723, 97.8474, 104.5433, 97.7585, 86.1848, 1884, 109.9268, 109.3321, 2390, 81.0156, 96.4318, 2108, 91.7200, 123.8792, 2708, 9090, 4.531573, 13, 'Denver, CO'); Results from template: {'roof_jobs_total': Decimal('4152'), 'gutter_jobs_total': Decimal('3458'), 'avg_adjusters': Decimal('90.2928'), 'title': u'St Paul, MN', 'window_approval_avg': Decimal('92.9658'), 'total_collections': Decimal('4.281469'), 'gutter_approval_avg': Decimal('120.1297'), 'avg_recruit': Decimal('95.3968'), 'siding_approval_avg': Decimal('100.2494'), 'window_jobs_total': Decimal('4256'), 'detail_id': 12L, 'siding_jobs_avg': Decimal('106.8845'), 'avg_inspect': Decimal('92.8178'), 'roof_approval_avg': Decimal('103.5420'), 'roof_jobs_avg': Decimal('103.5670'), 'total_jobs': Decimal('16151'), 'window_jobs_avg': Decimal('106.1611'), 'avg_contracts': Decimal('106.9622'), 'gutter_jobs_avg': Decimal('86.2559'), 'siding_jobs_total': Decimal('4285')} Tried tweaking it a few ways and running the results through various for loops, keep getting the same result where my results are a single row through the Django template and the expected results (through console) have 2 rows The row that is coming back is the same as the first row returned through the console query so I'm thinking that it is running correctly just a matter of passing the results through... for good measure this is the code I'm using to generate the query (yes it's a bit ugly, been playing with it) def sql_grouped(table, fields, group_by=False, where=False): from django.db import connection query = 'SELECT %s FROM %s' % (fields, table) if where: query = query + ' WHERE %s' % (where) if group_by: query = query + ' GROUP BY %s' % (group_by) cursor = connection.cursor() cursor.execute(query) desc = cursor.description data = [dict(zip([col[0] for col in desc], row)) for row in cursor.fetchall()] return data[0] any feedback is greatly appreciated - been tinkering with this since I realized I could skip a few steps by generating my averages directly within the SQL rather than post-process

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  • Multi-threaded random_r is slower than single threaded version.

    - by Nixuz
    The following program is essentially the same the one described here. When I run and compile the program using two threads (NTHREADS == 2), I get the following run times: real 0m14.120s user 0m25.570s sys 0m0.050s When it is run with just one thread (NTHREADS == 1), I get run times significantly better even though it is only using one core. real 0m4.705s user 0m4.660s sys 0m0.010s My system is dual core, and I know random_r is thread safe and I am pretty sure it is non-blocking. When the same program is run without random_r and a calculation of cosines and sines is used as a replacement, the dual-threaded version runs in about 1/2 the time as expected. #include <pthread.h> #include <stdlib.h> #include <stdio.h> #define NTHREADS 2 #define PRNG_BUFSZ 8 #define ITERATIONS 1000000000 void* thread_run(void* arg) { int r1, i, totalIterations = ITERATIONS / NTHREADS; for (i = 0; i < totalIterations; i++){ random_r((struct random_data*)arg, &r1); } printf("%i\n", r1); } int main(int argc, char** argv) { struct random_data* rand_states = (struct random_data*)calloc(NTHREADS, sizeof(struct random_data)); char* rand_statebufs = (char*)calloc(NTHREADS, PRNG_BUFSZ); pthread_t* thread_ids; int t = 0; thread_ids = (pthread_t*)calloc(NTHREADS, sizeof(pthread_t)); /* create threads */ for (t = 0; t < NTHREADS; t++) { initstate_r(random(), &rand_statebufs[t], PRNG_BUFSZ, &rand_states[t]); pthread_create(&thread_ids[t], NULL, &thread_run, &rand_states[t]); } for (t = 0; t < NTHREADS; t++) { pthread_join(thread_ids[t], NULL); } free(thread_ids); free(rand_states); free(rand_statebufs); } I am confused why when generating random numbers the two threaded version performs much worse than the single threaded version, considering random_r is meant to be used in multi-threaded applications.

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  • Django: testing get query

    - by Brant
    Okay, so I am sick of writing this... res = Something.objects.filter(asdf=something) if res: single = res[0] else: single = None if single: # do some stuff I would much rather be able to do something like this: single = Something.objects.filter(asdf=something) if single: #do some stuff I want to be able to grab a single object without testing the filtered results. In other words, when i know there is either going to be 1 or 0 matching entries, I would like to jump right to that entry, otherwise just get a 'None'. The DoesNotExist error that goes along with .get does not always work so well when trying to compress these queries into a single line. Is there any way to do what I have described?

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