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  • OpenCV compare two images and get different pixels

    - by Richard Knop
    For some reason the code bellow is not working. I have two 640*480 images which are very similar but not the same (at least few hundred/thousand pixels should be different). This is how I am comparing them and counting different pixels: unsigned char* row; unsigned char* row2; int count = 0; // this happens in a loop // fIplImageHeader is current image // lastFIplImageHeader is image from previous iteration if ( NULL != lastFIplImageHeader->imageData ) { for( int y = 0; y < fIplImageHeader->height; y++ ) { row = &CV_IMAGE_ELEM( fIplImageHeader, unsigned char, y, 0 ); row2 = &CV_IMAGE_ELEM( lastFIplImageHeader, unsigned char, y, 0 ); for( int x = 0; x < fIplImageHeader->width*fIplImageHeader->nChannels; x += fIplImageHeader->nChannels ) { if (row[x] == row2[x]) // the pixel in the first channel (usually G) { count++; } if (row[x+1] == row2[x+1]) // ... second channel (usually B) { count++; } if (row[x+2] == row2[x+2]) // ... third channel (usually R) { count++; } } } } Now at the end I get number 3626 which would seem alright. But, I tried opening one of the images in MS Paint and drawing thick red lines all over it which should increase the number of different pixels substantially. I got the same number again: 3626. Obviously I am doing something wrong here. I am comparing these images in a loop. This line is before the loop: IplImage* lastFIplImageHeader = cvCreateImageHeader(cvSize(640, 480), 8, 3); Then inside the loop I load images like this: IplImage* fIplImageHeader = cvLoadImage( filePath.c_str() ); // here I compare the pixels (the first code snippet) lastFIplImageHeader->imageData = fIplImageHeader->imageData; So lastFIplImageHeader is storing the image from the previous iteration and fIplImageHeader is storing the current image.

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  • Why isn't this json/jquery function returning 10 results and why does it return 0 sometimes?

    - by Scarface
    Hey guys, quick question. I have a json function returning results from a php query but it is not working out because it seems to keep executing the query until all results are returned and sometimes returns 0 results (if I keep refreshing page, it returns 0 results sometimes). I want to limit results returned to 10 so I was wondering if anyone could point out the error of my code. Would really appreciate it. PS I am positive the query is returning the correct results and only 10 on its own. It just seems to be this one function that is not working out. SELECT time, user, comment FROM comments WHERE topic_id='$topic_id' ORDER BY time DESC LIMIT 10 var count=0; function prepare(response) { count++; var string = '<li class="list" id="list-'+count+'">' +'</li>'; return string; } $.getJSON(files+"comments.php?action=view&load=initial&topic_id="+topic_id+"&t=" + (new Date()), function(json) { if(json.length) { for(i=0; i < json.length; i++) { $('#shoutbox-list').prepend(prepare(json[i])); $('#list-' + count).fadeIn(1500); } var j = i-1; lastTime = json[j].time; } });

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  • Limiting a search to records from last_request_at...

    - by bgadoci
    I am trying to figure out how to display a count for records that have been created in a table since the last_request_at of a user. In my view I am counting the notes of a question with the following code: <% unless @questions.empty? %> <% @questions.each do |question| %> <%= h(question.notes.count) %> end end This is happening in the /views/users/show.html.erb file. Instead of counting all the notes for the question, I would only like to count the notes that have been created since the users last_request_at datetime. I don't neccessarily want to scope notes to display this 'new notes' count application wide, just simply in this one instance. To accomplish I am assuming I need to create a variable in the User#show action and call it in the view but not really sure how to do that. Other information you may need: class Note < ActiveRecord::Base belongs_to :user belongs_to :question end class Question < ActiveRecord::Base has_many :notes, :dependent => :destroy belongs_to :user end

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  • Overhead of calling tiny functions from a tight inner loop? [C++]

    - by John
    Say you see a loop like this one: for(int i=0; i<thing.getParent().getObjectModel().getElements(SOME_TYPE).count(); ++i) { thing.getData().insert( thing.GetData().Count(), thing.getParent().getObjectModel().getElements(SOME_TYPE)[i].getName() ); } if this was Java I'd probably not think twice. But in performance-critical sections of C++, it makes me want to tinker with it... however I don't know if the compiler is smart enough to make it futile. This is a made up example but all it's doing is inserting strings into a container. Please don't assume any of these are STL types, think in general terms about the following: Is having a messy condition in the for loop going to get evaluated each time, or only once? If those get methods are simply returning references to member variables on the objects, will they be inlined away? Would you expect custom [] operators to get optimized at all? In other words is it worth the time (in performance only, not readability) to convert it to something like: ElementContainer &source = thing.getParent().getObjectModel().getElements(SOME_TYPE); int num = source.count(); Store &destination = thing.getData(); for(int i=0;i<num;++i) { destination.insert(thing.GetData().Count(), source[i].getName(); } Remember, this is a tight loop, called millions of times a second. What I wonder is if all this will shave a couple of cycles per loop or something more substantial? Yes I know the quote about "premature optimisation". And I know that profiling is important. But this is a more general question about modern compilers, Visual Studio in particular.

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  • Passing Data to Multi Threads

    - by alaamh
    I study this code from some book: #include <pthread.h> #include <stdio.h> /* Parameters to print_function. */ struct char_print_parms { /* The character to print. */ char character; /* The number of times to print it. */ int count; }; /* Prints a number of characters to stderr, as given by PARAMETERS, which is a pointer to a struct char_print_parms. */ void* char_print(void* parameters) { /* Cast the cookie pointer to the right type. */ struct char_print_parms* p = (struct char_print_parms*) parameters; int i; for (i = 0; i < p->count; ++i) fputc(p->character, stderr); return NULL; } /* The main program. */ int main() { pthread_t thread1_id; pthread_t thread2_id; struct char_print_parms thread1_args; struct char_print_parms thread2_args; /* Create a new thread to print 30,000 ’x’s. */ thread1_args.character = 'x'; thread1_args.count = 30000; pthread_create(&thread1_id, NULL, &char_print, &thread1_args); /* Create a new thread to print 20,000 o’s. */ thread2_args.character = 'o'; thread2_args.count = 20000; pthread_create(&thread2_id, NULL, &char_print, &thread2_args); usleep(20); return 0; } after running this code, I see different result each time. and some time corrupted result. what is wrong and what the correct way to do that?

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  • Java iterative vs recursive

    - by user1389813
    Can anyone explain why the following recursive method is faster than the iterative one (Both are doing it string concatenation) ? Isn't the iterative approach suppose to beat up the recursive one ? plus each recursive call adds a new layer on top of the stack which can be very space inefficient. private static void string_concat(StringBuilder sb, int count){ if(count >= 9999) return; string_concat(sb.append(count), count+1); } public static void main(String [] arg){ long s = System.currentTimeMillis(); StringBuilder sb = new StringBuilder(); for(int i = 0; i < 9999; i++){ sb.append(i); } System.out.println(System.currentTimeMillis()-s); s = System.currentTimeMillis(); string_concat(new StringBuilder(),0); System.out.println(System.currentTimeMillis()-s); } I ran the program multiple time, and the recursive one always ends up 3-4 times faster than the iterative one. What could be the main reason there that is causing the iterative one slower ?

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  • Unexpected crash while using looking phone numbers in iPhone address book

    - by FX
    I have a rather unexpected result with the following code: ABAddressBookRef addressBook = ABAddressBookCreate(); CFArrayRef people = ABAddressBookCopyArrayOfAllPeople(addressBook); CFIndex nPeople = ABAddressBookGetPersonCount(addressBook); NSLog (@"npeople = %d = %d", nPeople, CFArrayGetCount(people)); for (CFIndex i = 0; i < nPeople; i++) { ABRecordRef record = CFArrayGetValueAtIndex(people,i); ABMultiValueRef numbers = ABRecordCopyValue(record, kABPersonPhoneProperty); CFIndex count = ABMultiValueGetCount(numbers); NSLog (@"%d %d", i, count); } I never reach the second NSLog, it crashes on the call to ABMultiValueGetCount with: : * -[NSCFString count]: unrecognized selector sent to instance 0x383e72f4 : Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '** -[NSCFString count]: unrecognized selector sent to instance 0x383e72f4' In short, it's behaving as if my "numbers" variable was an NSString. While I wrote the code above myself, the same can be found in many examples on the web. Does someone here spot anything wrong with it? Oh, and also: it only crashes in Release mode (in debug mode, all is fine).

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  • Template neglects const (why?)

    - by Gabriel
    Does somebody know, why this compiles?? template< typename TBufferTypeFront, typename TBufferTypeBack = TBufferTypeFront> class FrontBackBuffer{ public: FrontBackBuffer( const TBufferTypeFront front, const TBufferTypeBack back): ////const reference assigned to reference??? m_Front(front), m_Back(back) { }; ~FrontBackBuffer() {}; TBufferTypeFront m_Front; ///< The front buffer TBufferTypeBack m_Back; ///< The back buffer }; int main(){ int b; int a; FrontBackBuffer<int&,int&> buffer(a,b); // buffer.m_Back = 33; buffer.m_Front = 55; } I compile with GCC 4.4. Why does it even let me compile this? Shouldn't there be an error that I cannot assign a const reference to a non-const reference?

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  • Satisfying indirect references at runtime.

    - by automatic
    I'm using C# and VS2010. I have a dll that I reference in my project (as a dll reference not a project reference). That dll (a.dll) references another dll that my project doesn't directly use, let's call it b.dll. None of these are in the GAC. My project compiles fine, but when I run it I get an exception that b.dll can't be found. It's not being copied to the bin directory when my project is compiled. What is the best way to get b.dll into the bin directory so that it can be found at run time. I've thought of four options. Use a post compile step to copy b.dll to the bin directory Add b.dll to my project (as a file) and specify copy to output directory if newer Add b.dll as a dll reference to my project. Use ILMerge to combine b.dll with a.dll I don't like 3 at all because it makes b.dll visible to my project, the other two seem like hacks. Am I missing other solutions? Which is the "right" way? Would a dependency injection framework be able to resolve and load b.dll?

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  • LinQ optimization

    - by Budda
    Here is a peace of code: void MyFunc(List<MyObj> objects) { MyFunc1(objects); foreach( MyObj obj in objects.Where(obj1=>obj1.Good)) { // Do Action With Good Object } } void MyFunc1(List<MyObj> objects) { int iGoodCount = objects.Where(obj1=>obj1.Good).Count(); BeHappy(iGoodCount); // do other stuff with 'objects' collection } Here we see that collection is analyzed twice and each time the value of 'Good' property is checked for each member: 1st time when calculating count of good objects, 2nd - when iterating through all good objects. It is desirable to have that optimized, and here is a straightforward solution: before call to MyFunc1 makecreate an additional temporary collection of good objects only (goodObjects, it can be IEnumerable); get count of these objects and pass it as an additional parameter to MyFunc1; in the 'MyFunc' method iterate not through 'objects.Where(...)' but through the 'goodObjects' collection. Not too bad approach (as far as I see), but additional parameter is required to be passed. Question: is there any LinQ out-of-the-box functionality that allows any caching during 1st Where().Count(), remembering a processed collection and use it in the next iteration? Any thoughts are welcome. Thanks.

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  • Retrieving Relationships from within two arrays of pointers

    - by DanF
    In a portion of a program I'm working on, I need to count all the times each person has worked on projects with each other person. Let's say we have "Employee" entities and "Session" entities. In each session, there are four project types, "A", "B", "C", & "D", each a many-to-many relationship to Employees. I'm making a loop to systematically review every person a selected person has worked with. First, I put all their project types in a single array, so it's easier to loop through, but by the time I ask the last nested Project for its Employee members, I get an "unrecognized selector" error. IBOutlet NSArrayController * list; int x; for(x = 0; x < [list count]; x++){ NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectAs"]; NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectBs"]; NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectCs"]; NSArray *A = [[list objectAtIndex:x] valueForKey:@"projectDs"]; NSArray *masterList = [[NSArray alloc] initWithObjects: projectAs, projectBs, projectCs, projectDs, nil]; int y; for(y = 0; y < [masterList count]; y++){ int z; for(z = 0; z < [[masterlist objectAtIndex:y] count]; z++){ //And now to make an Array of this employee's partners on the selected object, to run comparisons on. //I also have an array of keys for each session's teams, so that's what I'm referencing here: NSArray * thisTeam = [list objectAtIndex:y] objectAtIndex:z] valueForKey:projectKey]; This throws an exception... namely, -[_NSFaultingMutableSet objectAtIndex:]: unrecognized selector sent to instance What's wrong with that last Array creation?

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  • How do I grab hold of a pop-up that is opened from a frame?

    - by KLA
    I am testing a website using WatiN. On one of the pages I get a "report" in an Iframe, within this I frame there is a link to download and save the report. But since the only way to get to the link is to use frame.Link(...) the pop-up closes immediately after opening; Code snippet below //Click the create graph button ie.Button(Find.ById("ctl00_ctl00_ContentPlaceHolder1_TopBoxContentPlaceHolder_btnCreateGraph")).Click(); //Lets export the data ie.Div(Find.ById("colorbox")); ie.Div(Find.ById("cboxContent")); ie.Div(Find.ById("cboxLoadedContent")); Thread.Sleep(1000);//Used to cover performance issues Frame frame = ie.Frame(Find.ByName(frameNameRegex)); for (int Count = 0; Count < 10000000; Count++) {double nothing = (Count/12); }//Do nothing I just need a short pause //SelectList waits for a postback which does not occur. try { frame.SelectList(Find.ById("rvReport_ctl01_ctl05_ctl00")).SelectByValue("Excel"); } catch (Exception) { //Do nothing } //Now click export frame.Link(Find.ById("rvReport_ctl01_ctl05_ctl01")).ClickNoWait(); IE ieNewBrowserWindow = IE.AttachTo<IE>(Find.ByUrl(urlRegex)); fileDownloadHandler.WaitUntilFileDownloadDialogIsHandled(150); fileDownloadHandler.WaitUntilDownloadCompleted(200); I have tried using ie instead of frame which is why all those ie.Div's are present. if I use frame the pop-up window opens and closes instantly. If I use ie I get a link not found error. If I click on the link manually, while the test is "trying to find the link" the file will download correctly.

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  • Compression Program in C

    - by Delandilon
    I want to compress a series of characters. For example if i type Input : FFFFFBBBBBBBCCBBBAABBGGGGGSSS (27 x 8 bits = 216 bits) Output: F5B7C2B3A2B2G5S3 (14 x 8 bits = 112bits) So far this is what i have, i can count the number of Characters in the Array. But the most important task is to count them in the same sequence. I can't seem to figure that out :( Ive stared doing C just a few weeks back, i have knowledge on Array, pointers, ASCII value but in any case can't seem to count these characters in a sequence. Ive try a bit of everything. This approach is no good but it the closest i came to it. #include <stdio.h> #include <conio.h> int main() { int charcnt=0,dotcnt=0,commacnt=0,blankcnt=0,i, countA, countB; char str[125]; printf("*****String Manipulations*****\n\n"); printf("Enter a string\n\n"); scanf("%[^'\n']s",str); printf("\n\nEntered String is \" %s \" \n",str); for(i=0;str[i]!='\0';i++) { // COUNTING EXCEPTION CHARS if(str[i]==' ') blankcnt++; if(str[i]=='.') dotcnt++; if(str[i]==',') commacnt++; if (str[i]=='A' || str[i]=='a') countA++; if (str[i]=='B' || str[i]=='b') countA++; } //PRINT RESULT OF COUNT charcnt=i; printf("\n\nTotal Characters : %d",charcnt); printf("\nTotal Blanks : %d",blankcnt); printf("\nTotal Full stops : %d",dotcnt); printf("\nTotal Commas : %d\n\n",commacnt); printf("A%d\n", countA); }

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  • How to sort NSMutableArray? Code review needed

    - by JAM
    Good evening. This code works. It sorts an array of cards by both Suit and Card Value. It is also very much brute force. Can you recommend a better way? Does Objective-C help dealing with a situation where object being sorted itself has multiple fields, on which sorting depends? -(void) sort: (NSMutableArray *) deck { NSUInteger count = [deck count]; Card *thisCard; Card *nextCard; int this; int next; BOOL stillSwapping = true; while (stillSwapping) { stillSwapping = false; for (NSUInteger i = 0; i < count; ++i) { this = i; next = i+1; if (next < count) { thisCard = [deck objectAtIndex:this]; nextCard = [deck objectAtIndex:next]; if ([thisCard suit] > [nextCard suit]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } if ([thisCard suit] == [nextCard suit]) { if ([thisCard value] > [nextCard value]) { [deck exchangeObjectAtIndex:this withObjectAtIndex:next]; stillSwapping = true; } } } } } }

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  • Given a vector of maximum 10 000 natural and distinct numbers, find 4 numbers(a, b, c, d) such that

    - by king_kong
    Hi, I solved this problem by following a straightforward but not optimal algorithm. I sorted the vector in descending order and after that substracted numbers from max to min to see if I get a + b + c = d. Notice that I haven't used anywhere the fact that elements are natural, distinct and 10 000 at most. I suppose these details are the key. Does anyone here have a hint over an optimal way of solving this? Thank you in advance! Later Edit: My idea goes like this: '<<quicksort in descending order>>' for i:=0 to count { // after sorting, loop through the array int d := v[i]; for j:=i+1 to count { int dif1 := d - v[j]; int a := v[j]; for k:=j+1 to count { if (v[k] > dif1) continue; int dif2 := dif1 - v[k]; b := v[k]; for l:=k+1 to count { if (dif2 = v[l]) { c := dif2; return {a, b, c, d} } } } } } What do you think?(sorry for the bad indentation)

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  • Problems while trying to make a query with variables in the conditions (stored procedure)

    - by pablo89
    Hi!! Im having a problem, Im trying to do a query... I remember that in the past I did something like this but today this query is returning nothing, no error, no data, just nothing... the query is something like this: SELECT field1, @variableX:=field2 FROM table WHERE (SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=0)0 AND (SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=4)=0; I also tried this query but it didnt work (also it gaves no error): SELECT field1, @variableX:=field2, @variableY:=(SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=0), @variableZ:=(SELECT COUNT(fieldA) FROM table2 WHERE fieldB=@variableX AND fieldC=4) FROM table WHERE @variableY0 AND @variableZ=0; As you can see, what Im trying to do in the 1st query is use a variable in the conditions; in the 2nd query Im trying to create some variables and evaluate them in the conditions. At the end in the 2nd query the @variableY=1 AND @variableZ=0 but I dont know what the query returns an empty data What could be wrong here??? Any comment or suggest is welcome!!! thanks!!! Bye!!!

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  • Disable a control inside a gridview

    - by saeed talaee
    Hi i want to disable link-bottoms control in a grid view with the condition of a special value . for example if the count for a row become 0 ,the link bottom for that row should be invisible . what should i do? where should i write the code? here is cod that i write in row command grid view but it works only of i push the link bottom!! but i want to apply this cod to my page before loading. please guide me int idx = Convert.ToInt32(e.CommandArgument); idx = idx - (GridView1.PageSize * GridView1.PageIndex); int ID = (int)GridView1.DataKeys[idx].Value; string connStr = ConfigurationManager.ConnectionStrings["dbconn"].ConnectionString; SqlConnection sqlconn = new SqlConnection(connStr); SqlCommand sqlcmd = new SqlCommand(); sqlcmd = new SqlCommand("SELECT count(ID) FROM ReviwerArticle where ArticleID=@ArticleID", sqlconn); sqlcmd.Parameters.AddWithValue("@ArticleID", ID); sqlconn.Open(); int count = ((int)sqlcmd.ExecuteScalar()); sqlconn.Close(); if (count == 0) { ((LinkButton)GridView1.Rows[idx].Cells[0].FindControl("LinkButton4") as LinkButton).Visible = false; }

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  • replacing space with %20

    - by Codenotguru
    The following program replaces all spaces with %20.the compilation works fine but the program terminates during the runtime.Any help??? #include<iostream> #include<string> using namespace std; void removeSpaces(string url){ int len=url.length(); int i,count=0; while(i<=len){ if(url[i]==' ') count++; i++; } int length2=len+(count*2); string newarr[length2]; for(int j=len-1;j>=0;j--){ if(url[j]==' ') { newarr[length2-1]='0'; newarr[length2-2]='2'; newarr[length2-3]='%'; length2=length2-3; } else { newarr[length2-1]=url[j]; length2=length2-1; } } cout<<"\nThe number of spaces in the url is:"<<count; cout<<"\nThe replaced url is:"<<newarr; } int main(){ string url="http://www.ya h o o.com/"; removeSpaces(url); }

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  • Run Your Tests With Any NUnit Version

    - by Alois Kraus
    I always thought that the NUnit test runners and the test assemblies need to reference the same NUnit.Framework version. I wanted to be able to run my test assemblies with the newest GUI runner (currently 2.5.3). Ok so all I need to do is to reference both NUnit versions the newest one and the official for the current project. There is a nice article form Kent Bogart online how to reference the same assembly multiple times with different versions. The magic works by referencing one NUnit assembly with an alias which does prefix all types inside it. Then I could decorate my tests with the TestFixture and Test attribute from both NUnit versions and everything worked fine except that this was ugly. After playing a little bit around to make it simpler I found that I did not need to reference both NUnit.Framework assemblies. The test runners do not require the TestFixture and Test attribute in their specific version. That is really neat since the test runners are instructed by attributes what to do in a declarative way there is really no need to tie the runners to a specific version. At its core NUnit has this little method hidden to find matching TestFixtures and Tests   public bool CanBuildFrom(Type type) {     if (!(!type.IsAbstract || type.IsSealed))     {         return false;     }     return (((Reflect.HasAttribute(type,           "NUnit.Framework.TestFixtureAttribute", true) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestAttribute"       , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestCaseAttribute"   , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TheoryAttribute"     , true)); } That is versioning and backwards compatibility at its best. I tell NUnit what to do by decorating my tests classes with NUnit Attributes and the runner executes my intent without the need to bind me to a specific version. The contract between NUnit versions is actually a bit more complex (think of AssertExceptions) but this is also handled nicely by using not the concrete type but simply to check for the catched exception type by string. What can we learn from this? Versioning can be easy if the contract is small and the users of your library use it in a declarative way (Attributes). Everything beyond it will force you to reference several versions of the same assembly with all its consequences. Type equality is lost between versions so none of your casts will work. That means that you cannot simply use IBigInterface in two versions. You will need a wrapper to call the correct versioned one. To get out of this mess you can use one (and only one) version agnostic driver to encapsulate your business logic from the concrete versions. This is of course more work but as NUnit shows it can be easy. Simplicity is therefore not a nice thing to have but also requirement number one if you intend to make things more complex in version two and want to support any version (older and newer). Any interaction model above easy will not be maintainable. There are different approached to versioning. Below are my own personal observations how versioning works within the  .NET Framwork and NUnit.   Versioning Models 1. Bug Fixing and New Isolated Features When you only need to fix bugs there is no need to break anything. This is especially true when you have a big API surface. Microsoft did this with the .NET Framework 3.0 which did leave the CLR as is but delivered new assemblies for the features WPF, WCF and Windows Workflow Foundations. Their basic model was that the .NET 2.0 assemblies were declared as red assemblies which must not change (well mostly but each change was carefully reviewed to minimize the risk of breaking changes as much as possible) whereas the new green assemblies of .NET 3,3.5 did not have such obligations since they did implement new unrelated features which did not have any impact on the red assemblies. This is versioning strategy aimed at maximum compatibility and the delivery of new unrelated features. If you have a big API surface you should strive hard to do the same or you will break your customers code with every release. 2. New Breaking Features There are times when really new things need to be added to an existing product. The .NET Framework 4.0 did change the CLR in many ways which caused subtle different behavior although the API´s remained largely unchanged. Sometimes it is possible to simply recompile an application to make it work (e.g. changed method signature void Func() –> bool Func()) but behavioral changes need much more thought and cannot be automated. To minimize the impact .NET 2.0,3.0,3.5 applications will not automatically use the .NET 4.0 runtime when installed but they will keep using the “old” one. What is interesting is that a side by side execution model of both CLR versions (2 and 4) within one process is possible. Key to success was total isolation. You will have 2 GCs, 2 JIT compilers, 2 finalizer threads within one process. The two .NET runtimes cannot talk  (except via the usual IPC mechanisms) to each other. Both runtimes share nothing and run independently within the same process. This enables Explorer plugins written for the CLR 2.0 to work even when a CLR 4 plugin is already running inside the Explorer process. The price for isolation is an increased memory footprint because everything is loaded and running two times.   3. New Non Breaking Features It really depends where you break things. NUnit has evolved and many different Assert, Expect… methods have been added. These changes are all localized in the NUnit.Framework assembly which can be easily extended. As long as the test execution contract (TestFixture, Test, AssertException) remains stable it is possible to write test executors which can run tests written for NUnit 10 because the execution contract has not changed. It is possible to write software which executes other components in a version independent way but this is only feasible if the interaction model is relatively simple.   Versioning software is hard and it looks like it will remain hard since you suddenly work in a severely constrained environment when you try to innovate and to keep everything backwards compatible at the same time. These are contradicting goals and do not play well together. The easiest way out of this is to carefully watch what your customers are doing with your software. Minimizing the impact is much easier when you do not need to guess how many people will be broken when this or that is removed.

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  • WCF – interchangeable data-contract types

    - by nmarun
    In a WSDL based environment, unlike a CLR-world, we pass around the ‘state’ of an object and not the reference of an object. Well firstly, what does ‘state’ mean and does this also mean that we can send a struct where a class is expected (or vice-versa) as long as their ‘state’ is one and the same? Let’s see. So I have an operation contract defined as below: 1: [ServiceContract] 2: public interface ILearnWcfServiceExtend : ILearnWcfService 3: { 4: [OperationContract] 5: Employee SaveEmployee(Employee employee); 6: } 7:  8: [ServiceBehavior] 9: public class LearnWcfService : ILearnWcfServiceExtend 10: { 11: public Employee SaveEmployee(Employee employee) 12: { 13: employee.EmployeeId = 123; 14: return employee; 15: } 16: } Quite simplistic operation there (which translates to ‘absolutely no business value’). Now, the data contract Employee mentioned above is a struct. 1: public struct Employee 2: { 3: public int EmployeeId { get; set; } 4:  5: public string FName { get; set; } 6: } After compilation and consumption of this service, my proxy (in the Reference.cs file) looks like below (I’ve ignored the rest of the details just to avoid unwanted confusion): 1: public partial struct Employee : System.Runtime.Serialization.IExtensibleDataObject, System.ComponentModel.INotifyPropertyChanged I call the service with the code below: 1: private static void CallWcfService() 2: { 3: Employee employee = new Employee { FName = "A" }; 4: Console.WriteLine("IsValueType: {0}", employee.GetType().IsValueType); 5: Console.WriteLine("IsClass: {0}", employee.GetType().IsClass); 6: Console.WriteLine("Before calling the service: {0} - {1}", employee.EmployeeId, employee.FName); 7: employee = LearnWcfServiceClient.SaveEmployee(employee); 8: Console.WriteLine("Return from the service: {0} - {1}", employee.EmployeeId, employee.FName); 9: } The output is: I now change my Employee type from a struct to a class in the proxy class and run the application: 1: public partial class Employee : System.Runtime.Serialization.IExtensibleDataObject, System.ComponentModel.INotifyPropertyChanged { The output this time is: The state of an object implies towards its composition, the properties and the values of these properties and not based on whether it is a reference type (class) or a value type (struct). And as shown above, we’re actually passing an object by its state and not by reference. Continuing on the same topic of ‘type-interchangeability’, WCF treats two data contracts as equivalent if they have the same ‘wire-representation’. We can do so using the DataContract and DataMember attributes’ Name property. 1: [DataContract] 2: public struct Person 3: { 4: [DataMember] 5: public int Id { get; set; } 6:  7: [DataMember] 8: public string FirstName { get; set; } 9: } 10:  11: [DataContract(Name="Person")] 12: public class Employee 13: { 14: [DataMember(Name = "Id")] 15: public int EmployeeId { get; set; } 16:  17: [DataMember(Name="FirstName")] 18: public string FName { get; set; } 19: } I’ve created two data contracts with the exact same wire-representation. Just remember that the names and the types of data members need to match to be considered equivalent. The question then arises as to what gets generated in the proxy class. Despite us declaring two data contracts (Person and Employee), only one gets emitted – Person. This is because we’re saying that the Employee type has the same wire-representation as the Person type. Also that the signature of the SaveEmployee operation gets changed on the proxy side: 1: [System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "4.0.0.0")] 2: [System.ServiceModel.ServiceContractAttribute(ConfigurationName="ServiceProxy.ILearnWcfServiceExtend")] 3: public interface ILearnWcfServiceExtend 4: { 5: [System.ServiceModel.OperationContractAttribute(Action="http://tempuri.org/ILearnWcfServiceExtend/SaveEmployee", ReplyAction="http://tempuri.org/ILearnWcfServiceExtend/SaveEmployeeResponse")] 6: ClientApplication.ServiceProxy.Person SaveEmployee(ClientApplication.ServiceProxy.Person employee); 7: } But, on the service side, the SaveEmployee still accepts and returns an Employee data contract. 1: [ServiceBehavior] 2: public class LearnWcfService : ILearnWcfServiceExtend 3: { 4: public Employee SaveEmployee(Employee employee) 5: { 6: employee.EmployeeId = 123; 7: return employee; 8: } 9: } Despite all these changes, our output remains the same as the last one: This is type-interchangeability at work! Here’s one more thing to ponder about. Our Person type is a struct and Employee type is a class. Then how is it that the Person type got emitted as a ‘class’ in the proxy? It’s worth mentioning that WSDL describes a type called Employee and does not say whether it is a class or a struct (see the SOAP message below): 1: <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" 2: xmlns:tem="http://tempuri.org/" 3: xmlns:ser="http://schemas.datacontract.org/2004/07/ServiceApplication"> 4: <soapenv:Header/> 5: <soapenv:Body> 6: <tem:SaveEmployee> 7: <!--Optional:--> 8: <tem:employee> 9: <!--Optional:--> 10: <ser:EmployeeId>?</ser:EmployeeId> 11: <!--Optional:--> 12: <ser:FName>?</ser:FName> 13: </tem:employee> 14: </tem:SaveEmployee> 15: </soapenv:Body> 16: </soapenv:Envelope> There are some differences between how ‘Add Service Reference’ and the svcutil.exe generate the proxy class, but turns out both do some kind of reflection and determine the type of the data contract and emit the code accordingly. So since the Employee type is a class, the proxy ‘Person’ type gets generated as a class. In fact, reflecting on svcutil.exe application, you’ll see that there are a couple of places wherein a flag actually determines a type as a class or a struct. One example is in the ExportISerializableDataContract method in the System.Runtime.Serialization.CodeExporter class. Seems like these flags have a say in deciding whether the type gets emitted as a struct or a class. This behavior is different if you use the WSDL tool though. WSDL tool does not do any kind of reflection of the data contract / serialized type, it emits the type as a class by default. You can check this using the two command lines below:   Note to self: Remember ‘state’ and type-interchangeability when traversing through the WSDL planet!

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  • LibPCL issues on Ubuntu 13.10

    - by user254885
    i wanted to install the Point Cloud Library but it does not work i use an ODROID board(ARM processor) Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: libpcl-all : Depends: libpcl-1.7-all but it is not going to be installed E: Unable to correct problems, you have held broken packages. by compiling v1.7 , i get these errors : /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(ptw-fcntl.o): In function `__fcntl_nocancel': /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/i386/fcntl.c:37: undefined reference to `__libc_do_syscall' /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(ptw-fcntl.o): In function `__libc_fcntl': /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/i386/fcntl.c:53: undefined reference to `__libc_do_syscall' /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/i386/fcntl.c:57: undefined reference to `__libc_do_syscall' /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(ptw-open64.o): In function `__libc_open64': /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/open64.c:41: undefined reference to `__libc_do_syscall' /build/buildd/eglibc-2.17/nptl/../sysdeps/unix/sysv/linux/open64.c:45: undefined reference to `__libc_do_syscall' /usr/lib/gcc/arm-linux-gnueabihf/4.8/../../../arm-linux-gnueabihf/libpthread.a(cancellation.o):/build/buildd/eglibc-2.17/nptl/cancellation.c:96: more undefined references to `__libc_do_syscall' follow collect2: error: ld returned 1 exit status make[2]: *** [bin/pcl_convert_pcd_ascii_binary] Error 1 make[1]: *** [io/tools/CMakeFiles/pcl_convert_pcd_ascii_binary.dir/all] Error 2 make: *** [all] Error 2 i could not find anything in google to solve these errors i believe some packages were not ported for ARM processors any help would be appreciated $ dpkg --list | grep headers ii linux-headers-3.0.63-odroidx2 20130215 ii linux-headers-3.0.71-odroidx2 20130415 ii linux-headers-3.0.74-odroidx2 20130417 ii linux-headers-3.0.75-odroidx2 20130426 ii linux-headers-3.1.10-6 3.1.10-6.10 ii linux-headers-3.1.10-6-ac100 3.1.10-6.10 ii linux-headers-ac100 3.1.10.6.2 installing packages did'nt do well sudo apt-get install linux-generic [sudo] password for odroid: Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: debugedit libasound2-dev libestools2.1-dev librpmbuild3 librpmsign1 thunderbird-locale-en thunderbird-locale-en-gb thunderbird-locale-en-us thunderbird-locale-ko Use 'apt-get autoremove' to remove them. The following extra packages will be installed: linux-headers-3.11.0-17 linux-headers-3.11.0-17-generic linux-headers-generic linux-image-3.11.0-17-generic linux-image-generic Suggested packages: fdutils linux-doc-3.11.0 linux-source-3.11.0 linux-tools The following NEW packages will be installed: linux-generic linux-headers-3.11.0-17 linux-headers-3.11.0-17-generic linux-headers-generic linux-image-3.11.0-17-generic linux-image-generic 0 upgraded, 6 newly installed, 0 to remove and 0 not upgraded. Need to get 58.2 MB of archives. After this operation, 203 MB of additional disk space will be used. Do you want to continue [Y/n]? y Get:1 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-image-3.11.0-17-generic armhf 3.11.0-17.31 [44.5 MB] Get:2 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-image-generic armhf 3.11.0.17.18 [2,356 B] Get:3 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-headers-3.11.0-17 all 3.11.0-17.31 [12.6 MB] Get:4 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-headers-3.11.0-17-generic armhf 3.11.0-17.31 [1,128 kB] Get:5 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-headers-generic armhf 3.11.0.17.18 [2,350 B] Get:6 http://ports.ubuntu.com/ubuntu-ports/ saucy-updates/main linux-generic armhf 3.11.0.17.18 [1,726 B] Fetched 58.2 MB in 13s (4,379 kB/s) Selecting previously unselected package linux-image-3.11.0-17-generic. (Reading database ... 258618 files and directories currently installed.) Unpacking linux-image-3.11.0-17-generic (from .../linux-image-3.11.0-17-generic_3.11.0-17.31_armhf.deb) ... Examining /etc/kernel/preinst.d/ Done. Selecting previously unselected package linux-image-generic. Unpacking linux-image-generic (from .../linux-image-generic_3.11.0.17.18_armhf.deb) ... Selecting previously unselected package linux-headers-3.11.0-17. Unpacking linux-headers-3.11.0-17 (from .../linux-headers-3.11.0-17_3.11.0-17.31_all.deb) ... Selecting previously unselected package linux-headers-3.11.0-17-generic. Unpacking linux-headers-3.11.0-17-generic (from .../linux-headers-3.11.0-17-generic_3.11.0-17.31_armhf.deb) ... Selecting previously unselected package linux-headers-generic. Unpacking linux-headers-generic (from .../linux-headers-generic_3.11.0.17.18_armhf.deb) ... Selecting previously unselected package linux-generic. Unpacking linux-generic (from .../linux-generic_3.11.0.17.18_armhf.deb) ... Setting up linux-image-3.11.0-17-generic (3.11.0-17.31) ... Running depmod. update-initramfs: deferring update (hook will be called later) cp: cannot stat ‘/boot/initrd.img-3.11.0-17-generic’: No such file or directory Failed to copy /boot/initrd.img-3.11.0-17-generic to /boot/initrd.img at /var/lib/dpkg/info/linux-image-3.11.0-17-generic.postinst line 730. dpkg: error processing linux-image-3.11.0-17-generic (--configure): subprocess installed post-installation script returned error exit status 2 dpkg: dependency problems prevent configuration of linux-image-generic: linux-image-generic depends on linux-image-3.11.0-17-generic; however: Package linux-image-3.11.0-17-generic is not configured yet. dpkg: error processing linux-image-generic (--configure): dependency problems - leaving unconfigured Setting up linux-headers-3.11.0-17 (3.11.0-17.31) ... No apport report written because MaxReports is reached already No apport report written because MaxReports is reached already Setting up linux-headers-3.11.0-17-generic (3.11.0-17.31) ... Examining /etc/kernel/header_postinst.d. Setting up linux-headers-generic (3.11.0.17.18) ... dpkg: dependency problems prevent configuration of linux-generic: linux-generic depends on linux-image-generic (= 3.11.0.17.18); however: Package linux-image-generic is not configured yet. dpkg: error processing linux-generic (--configure): dependency problems - leaving unconfigured No apport report written because MaxReports is reached already Errors were encountered while processing: linux-image-3.11.0-17-generic linux-image-generic linux-generic E: Sub-process /usr/bin/dpkg returned an error code (1) i had to uninstall these cos they were messing up other packages installation(buildessentials were already installed)

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  • Fun with Aggregates

    - by Paul White
    There are interesting things to be learned from even the simplest queries.  For example, imagine you are given the task of writing a query to list AdventureWorks product names where the product has at least one entry in the transaction history table, but fewer than ten. One possible query to meet that specification is: SELECT p.Name FROM Production.Product AS p JOIN Production.TransactionHistory AS th ON p.ProductID = th.ProductID GROUP BY p.ProductID, p.Name HAVING COUNT_BIG(*) < 10; That query correctly returns 23 rows (execution plan and data sample shown below): The execution plan looks a bit different from the written form of the query: the base tables are accessed in reverse order, and the aggregation is performed before the join.  The general idea is to read all rows from the history table, compute the count of rows grouped by ProductID, merge join the results to the Product table on ProductID, and finally filter to only return rows where the count is less than ten. This ‘fully-optimized’ plan has an estimated cost of around 0.33 units.  The reason for the quote marks there is that this plan is not quite as optimal as it could be – surely it would make sense to push the Filter down past the join too?  To answer that, let’s look at some other ways to formulate this query.  This being SQL, there are any number of ways to write logically-equivalent query specifications, so we’ll just look at a couple of interesting ones.  The first query is an attempt to reverse-engineer T-SQL from the optimized query plan shown above.  It joins the result of pre-aggregating the history table to the Product table before filtering: SELECT p.Name FROM ( SELECT th.ProductID, cnt = COUNT_BIG(*) FROM Production.TransactionHistory AS th GROUP BY th.ProductID ) AS q1 JOIN Production.Product AS p ON p.ProductID = q1.ProductID WHERE q1.cnt < 10; Perhaps a little surprisingly, we get a slightly different execution plan: The results are the same (23 rows) but this time the Filter is pushed below the join!  The optimizer chooses nested loops for the join, because the cardinality estimate for rows passing the Filter is a bit low (estimate 1 versus 23 actual), though you can force a merge join with a hint and the Filter still appears below the join.  In yet another variation, the < 10 predicate can be ‘manually pushed’ by specifying it in a HAVING clause in the “q1” sub-query instead of in the WHERE clause as written above. The reason this predicate can be pushed past the join in this query form, but not in the original formulation is simply an optimizer limitation – it does make efforts (primarily during the simplification phase) to encourage logically-equivalent query specifications to produce the same execution plan, but the implementation is not completely comprehensive. Moving on to a second example, the following query specification results from phrasing the requirement as “list the products where there exists fewer than ten correlated rows in the history table”: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) < 10 ); Unfortunately, this query produces an incorrect result (86 rows): The problem is that it lists products with no history rows, though the reasons are interesting.  The COUNT_BIG(*) in the EXISTS clause is a scalar aggregate (meaning there is no GROUP BY clause) and scalar aggregates always produce a value, even when the input is an empty set.  In the case of the COUNT aggregate, the result of aggregating the empty set is zero (the other standard aggregates produce a NULL).  To make the point really clear, let’s look at product 709, which happens to be one for which no history rows exist: -- Scalar aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709;   -- Vector aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709 GROUP BY th.ProductID; The estimated execution plans for these two statements are almost identical: You might expect the Stream Aggregate to have a Group By for the second statement, but this is not the case.  The query includes an equality comparison to a constant value (709), so all qualified rows are guaranteed to have the same value for ProductID and the Group By is optimized away. In fact there are some minor differences between the two plans (the first is auto-parameterized and qualifies for trivial plan, whereas the second is not auto-parameterized and requires cost-based optimization), but there is nothing to indicate that one is a scalar aggregate and the other is a vector aggregate.  This is something I would like to see exposed in show plan so I suggested it on Connect.  Anyway, the results of running the two queries show the difference at runtime: The scalar aggregate (no GROUP BY) returns a result of zero, whereas the vector aggregate (with a GROUP BY clause) returns nothing at all.  Returning to our EXISTS query, we could ‘fix’ it by changing the HAVING clause to reject rows where the scalar aggregate returns zero: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) BETWEEN 1 AND 9 ); The query now returns the correct 23 rows: Unfortunately, the execution plan is less efficient now – it has an estimated cost of 0.78 compared to 0.33 for the earlier plans.  Let’s try adding a redundant GROUP BY instead of changing the HAVING clause: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY th.ProductID HAVING COUNT_BIG(*) < 10 ); Not only do we now get correct results (23 rows), this is the execution plan: I like to compare that plan to quantum physics: if you don’t find it shocking, you haven’t understood it properly :)  The simple addition of a redundant GROUP BY has resulted in the EXISTS form of the query being transformed into exactly the same optimal plan we found earlier.  What’s more, in SQL Server 2008 and later, we can replace the odd-looking GROUP BY with an explicit GROUP BY on the empty set: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ); I offer that as an alternative because some people find it more intuitive (and it perhaps has more geek value too).  Whichever way you prefer, it’s rather satisfying to note that the result of the sub-query does not exist for a particular correlated value where a vector aggregate is used (the scalar COUNT aggregate always returns a value, even if zero, so it always ‘EXISTS’ regardless which ProductID is logically being evaluated). The following query forms also produce the optimal plan and correct results, so long as a vector aggregate is used (you can probably find more equivalent query forms): WHERE Clause SELECT p.Name FROM Production.Product AS p WHERE ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) < 10; APPLY SELECT p.Name FROM Production.Product AS p CROSS APPLY ( SELECT NULL FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ) AS ca (dummy); FROM Clause SELECT q1.Name FROM ( SELECT p.Name, cnt = ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) FROM Production.Product AS p ) AS q1 WHERE q1.cnt < 10; This last example uses SUM(1) instead of COUNT and does not require a vector aggregate…you should be able to work out why :) SELECT q.Name FROM ( SELECT p.Name, cnt = ( SELECT SUM(1) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID ) FROM Production.Product AS p ) AS q WHERE q.cnt < 10; The semantics of SQL aggregates are rather odd in places.  It definitely pays to get to know the rules, and to be careful to check whether your queries are using scalar or vector aggregates.  As we have seen, query plans do not show in which ‘mode’ an aggregate is running and getting it wrong can cause poor performance, wrong results, or both. © 2012 Paul White Twitter: @SQL_Kiwi email: [email protected]

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  • SSIS: Deploying OLAP cubes using C# script tasks and AMO

    - by DrJohn
    As part of the continuing series on Building dynamic OLAP data marts on-the-fly, this blog entry will focus on how to automate the deployment of OLAP cubes using SQL Server Integration Services (SSIS) and Analysis Services Management Objects (AMO). OLAP cube deployment is usually done using the Analysis Services Deployment Wizard. However, this option was dismissed for a variety of reasons. Firstly, invoking external processes from SSIS is fraught with problems as (a) it is not always possible to ensure SSIS waits for the external program to terminate; (b) we cannot log the outcome properly and (c) it is not always possible to control the server's configuration to ensure the executable works correctly. Another reason for rejecting the Deployment Wizard is that it requires the 'answers' to be written into four XML files. These XML files record the three things we need to change: the name of the server, the name of the OLAP database and the connection string to the data mart. Although it would be reasonably straight forward to change the content of the XML files programmatically, this adds another set of complication and level of obscurity to the overall process. When I first investigated the possibility of using C# to deploy a cube, I was surprised to find that there are no other blog entries about the topic. I can only assume everyone else is happy with the Deployment Wizard! SSIS "forgets" assembly references If you build your script task from scratch, you will have to remember how to overcome one of the major annoyances of working with SSIS script tasks: the forgetful nature of SSIS when it comes to assembly references. Basically, you can go through the process of adding an assembly reference using the Add Reference dialog, but when you close the script window, SSIS "forgets" the assembly reference so the script will not compile. After repeating the operation several times, you will find that SSIS only remembers the assembly reference when you specifically press the Save All icon in the script window. This problem is not unique to the AMO assembly and has certainly been a "feature" since SQL Server 2005, so I am not amazed it is still present in SQL Server 2008 R2! Sample Package So let's take a look at the sample SSIS package I have provided which can be downloaded from here: DeployOlapCubeExample.zip  Below is a screenshot after a successful run. Connection Managers The package has three connection managers: AsDatabaseDefinitionFile is a file connection manager pointing to the .asdatabase file you wish to deploy. Note that this can be found in the bin directory of you OLAP database project once you have clicked the "Build" button in Visual Studio TargetOlapServerCS is an Analysis Services connection manager which identifies both the deployment server and the target database name. SourceDataMart is an OLEDB connection manager pointing to the data mart which is to act as the source of data for your cube. This will be used to replace the connection string found in your .asdatabase file Once you have configured the connection managers, the sample should run and deploy your OLAP database in a few seconds. Of course, in a production environment, these connection managers would be associated with package configurations or set at runtime. When you run the sample, you should see that the script logs its activity to the output screen (see screenshot above). If you configure logging for the package, then these messages will also appear in your SSIS logging. Sample Code Walkthrough Next let's walk through the code. The first step is to parse the connection string provided by the TargetOlapServerCS connection manager and obtain the name of both the target OLAP server and also the name of the OLAP database. Note that the target database does not have to exist to be referenced in an AS connection manager, so I am using this as a convenient way to define both properties. We now connect to the server and check for the existence of the OLAP database. If it exists, we drop the database so we can re-deploy. svr.Connect(olapServerName); if (svr.Connected) { // Drop the OLAP database if it already exists Database db = svr.Databases.FindByName(olapDatabaseName); if (db != null) { db.Drop(); } // rest of script } Next we start building the XMLA command that will actually perform the deployment. Basically this is a small chuck of XML which we need to wrap around the large .asdatabase file generated by the Visual Studio build process. // Start generating the main part of the XMLA command XmlDocument xmlaCommand = new XmlDocument(); xmlaCommand.LoadXml(string.Format("<Batch Transaction='false' xmlns='http://schemas.microsoft.com/analysisservices/2003/engine'><Alter AllowCreate='true' ObjectExpansion='ExpandFull'><Object><DatabaseID>{0}</DatabaseID></Object><ObjectDefinition/></Alter></Batch>", olapDatabaseName));  Next we need to merge two XML files which we can do by simply using setting the InnerXml property of the ObjectDefinition node as follows: // load OLAP Database definition from .asdatabase file identified by connection manager XmlDocument olapCubeDef = new XmlDocument(); olapCubeDef.Load(Dts.Connections["AsDatabaseDefinitionFile"].ConnectionString); // merge the two XML files by obtain a reference to the ObjectDefinition node oaRootNode.InnerXml = olapCubeDef.InnerXml;   One hurdle I had to overcome was removing detritus from the .asdabase file left by the Visual Studio build. Through an iterative process, I found I needed to remove several nodes as they caused the deployment to fail. The XMLA error message read "Cannot set read-only node: CreatedTimestamp" or similar. In comparing the XMLA generated with by the Deployment Wizard with that generated by my code, these read-only nodes were missing, so clearly I just needed to strip them out. This was easily achieved using XPath to find the relevant XML nodes, of which I show one example below: foreach (XmlNode node in rootNode.SelectNodes("//ns1:CreatedTimestamp", nsManager)) { node.ParentNode.RemoveChild(node); } Now we need to change the database name in both the ID and Name nodes using code such as: XmlNode databaseID = xmlaCommand.SelectSingleNode("//ns1:Database/ns1:ID", nsManager); if (databaseID != null) databaseID.InnerText = olapDatabaseName; Finally we need to change the connection string to point at the relevant data mart. Again this is easily achieved using XPath to search for the relevant nodes and then replace the content of the node with the new name or connection string. XmlNode connectionStringNode = xmlaCommand.SelectSingleNode("//ns1:DataSources/ns1:DataSource/ns1:ConnectionString", nsManager); if (connectionStringNode != null) { connectionStringNode.InnerText = Dts.Connections["SourceDataMart"].ConnectionString; } Finally we need to perform the deployment using the Execute XMLA command and check the returned XmlaResultCollection for errors before setting the Dts.TaskResult. XmlaResultCollection oResults = svr.Execute(xmlaCommand.InnerXml);  // check for errors during deployment foreach (Microsoft.AnalysisServices.XmlaResult oResult in oResults) { foreach (Microsoft.AnalysisServices.XmlaMessage oMessage in oResult.Messages) { if ((oMessage.GetType().Name == "XmlaError")) { FireError(oMessage.Description); HadError = true; } } } If you are not familiar with XML programming, all this may all seem a bit daunting, but perceiver as the sample code is pretty short. If you would like the script to process the OLAP database, simply uncomment the lines in the vicinity of Process method. Of course, you can extend the script to perform your own custom processing and to even synchronize the database to a front-end server. Personally, I like to keep the deployment and processing separate as the code can become overly complex for support staff.If you want to know more, come see my session at the forthcoming SQLBits conference.

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  • Fun with Aggregates

    - by Paul White
    There are interesting things to be learned from even the simplest queries.  For example, imagine you are given the task of writing a query to list AdventureWorks product names where the product has at least one entry in the transaction history table, but fewer than ten. One possible query to meet that specification is: SELECT p.Name FROM Production.Product AS p JOIN Production.TransactionHistory AS th ON p.ProductID = th.ProductID GROUP BY p.ProductID, p.Name HAVING COUNT_BIG(*) < 10; That query correctly returns 23 rows (execution plan and data sample shown below): The execution plan looks a bit different from the written form of the query: the base tables are accessed in reverse order, and the aggregation is performed before the join.  The general idea is to read all rows from the history table, compute the count of rows grouped by ProductID, merge join the results to the Product table on ProductID, and finally filter to only return rows where the count is less than ten. This ‘fully-optimized’ plan has an estimated cost of around 0.33 units.  The reason for the quote marks there is that this plan is not quite as optimal as it could be – surely it would make sense to push the Filter down past the join too?  To answer that, let’s look at some other ways to formulate this query.  This being SQL, there are any number of ways to write logically-equivalent query specifications, so we’ll just look at a couple of interesting ones.  The first query is an attempt to reverse-engineer T-SQL from the optimized query plan shown above.  It joins the result of pre-aggregating the history table to the Product table before filtering: SELECT p.Name FROM ( SELECT th.ProductID, cnt = COUNT_BIG(*) FROM Production.TransactionHistory AS th GROUP BY th.ProductID ) AS q1 JOIN Production.Product AS p ON p.ProductID = q1.ProductID WHERE q1.cnt < 10; Perhaps a little surprisingly, we get a slightly different execution plan: The results are the same (23 rows) but this time the Filter is pushed below the join!  The optimizer chooses nested loops for the join, because the cardinality estimate for rows passing the Filter is a bit low (estimate 1 versus 23 actual), though you can force a merge join with a hint and the Filter still appears below the join.  In yet another variation, the < 10 predicate can be ‘manually pushed’ by specifying it in a HAVING clause in the “q1” sub-query instead of in the WHERE clause as written above. The reason this predicate can be pushed past the join in this query form, but not in the original formulation is simply an optimizer limitation – it does make efforts (primarily during the simplification phase) to encourage logically-equivalent query specifications to produce the same execution plan, but the implementation is not completely comprehensive. Moving on to a second example, the following query specification results from phrasing the requirement as “list the products where there exists fewer than ten correlated rows in the history table”: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) < 10 ); Unfortunately, this query produces an incorrect result (86 rows): The problem is that it lists products with no history rows, though the reasons are interesting.  The COUNT_BIG(*) in the EXISTS clause is a scalar aggregate (meaning there is no GROUP BY clause) and scalar aggregates always produce a value, even when the input is an empty set.  In the case of the COUNT aggregate, the result of aggregating the empty set is zero (the other standard aggregates produce a NULL).  To make the point really clear, let’s look at product 709, which happens to be one for which no history rows exist: -- Scalar aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709;   -- Vector aggregate SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = 709 GROUP BY th.ProductID; The estimated execution plans for these two statements are almost identical: You might expect the Stream Aggregate to have a Group By for the second statement, but this is not the case.  The query includes an equality comparison to a constant value (709), so all qualified rows are guaranteed to have the same value for ProductID and the Group By is optimized away. In fact there are some minor differences between the two plans (the first is auto-parameterized and qualifies for trivial plan, whereas the second is not auto-parameterized and requires cost-based optimization), but there is nothing to indicate that one is a scalar aggregate and the other is a vector aggregate.  This is something I would like to see exposed in show plan so I suggested it on Connect.  Anyway, the results of running the two queries show the difference at runtime: The scalar aggregate (no GROUP BY) returns a result of zero, whereas the vector aggregate (with a GROUP BY clause) returns nothing at all.  Returning to our EXISTS query, we could ‘fix’ it by changing the HAVING clause to reject rows where the scalar aggregate returns zero: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID HAVING COUNT_BIG(*) BETWEEN 1 AND 9 ); The query now returns the correct 23 rows: Unfortunately, the execution plan is less efficient now – it has an estimated cost of 0.78 compared to 0.33 for the earlier plans.  Let’s try adding a redundant GROUP BY instead of changing the HAVING clause: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY th.ProductID HAVING COUNT_BIG(*) < 10 ); Not only do we now get correct results (23 rows), this is the execution plan: I like to compare that plan to quantum physics: if you don’t find it shocking, you haven’t understood it properly :)  The simple addition of a redundant GROUP BY has resulted in the EXISTS form of the query being transformed into exactly the same optimal plan we found earlier.  What’s more, in SQL Server 2008 and later, we can replace the odd-looking GROUP BY with an explicit GROUP BY on the empty set: SELECT p.Name FROM Production.Product AS p WHERE EXISTS ( SELECT * FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ); I offer that as an alternative because some people find it more intuitive (and it perhaps has more geek value too).  Whichever way you prefer, it’s rather satisfying to note that the result of the sub-query does not exist for a particular correlated value where a vector aggregate is used (the scalar COUNT aggregate always returns a value, even if zero, so it always ‘EXISTS’ regardless which ProductID is logically being evaluated). The following query forms also produce the optimal plan and correct results, so long as a vector aggregate is used (you can probably find more equivalent query forms): WHERE Clause SELECT p.Name FROM Production.Product AS p WHERE ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) < 10; APPLY SELECT p.Name FROM Production.Product AS p CROSS APPLY ( SELECT NULL FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () HAVING COUNT_BIG(*) < 10 ) AS ca (dummy); FROM Clause SELECT q1.Name FROM ( SELECT p.Name, cnt = ( SELECT COUNT_BIG(*) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID GROUP BY () ) FROM Production.Product AS p ) AS q1 WHERE q1.cnt < 10; This last example uses SUM(1) instead of COUNT and does not require a vector aggregate…you should be able to work out why :) SELECT q.Name FROM ( SELECT p.Name, cnt = ( SELECT SUM(1) FROM Production.TransactionHistory AS th WHERE th.ProductID = p.ProductID ) FROM Production.Product AS p ) AS q WHERE q.cnt < 10; The semantics of SQL aggregates are rather odd in places.  It definitely pays to get to know the rules, and to be careful to check whether your queries are using scalar or vector aggregates.  As we have seen, query plans do not show in which ‘mode’ an aggregate is running and getting it wrong can cause poor performance, wrong results, or both. © 2012 Paul White Twitter: @SQL_Kiwi email: [email protected]

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  • C to C++ Conversion [closed]

    - by Annalyne
    Can someone convert this code to C++, pretty please? :( #include <stdio.h> #include <stdlib.h> #include <time.h> #define WEAPON_ROPE 10 #define WEAPON_REVOLVER 20 #define WEAPON_LEADPIPE 30 #define WEAPON_CANDLESTICK 40 #define WEAPON_KNIFE 50 #define WEAPON_WRENCH 60 #define PEOPLE_MRGREEN 100 #define PEOPLE_MSSCARLET 200 #define PEOPLE_CONLMUSTARD 300 #define PEOPLE_PROFPLUM 400 #define PEOPLE_MISPEACOCK 500 #define PEOPLE_MISWHITE 600 #define PLACE_KITCHEN 1 #define PLACE_HALL 2 #define PLACE_POOLROOM 3 #define PLACE_STUDY 4 #define PLACE_LOUNG 5 #define PLACE_LIBRARY 6 #define PLACE_CONSERVATORY 7 #define PLACE_DINING 8 #define PLACE_BILLIARDS 9 int main() { int die = 0; int players[6][9] = {{0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0}}; int allCards[] = {WEAPON_ROPE, WEAPON_REVOLVER, WEAPON_LEADPIPE, WEAPON_CANDLESTICK, WEAPON_CANDLESTICK, WEAPON_KNIFE, WEAPON_WRENCH, PEOPLE_MRGREEN, PEOPLE_MSSCARLET, PEOPLE_CONLMUSTARD, PEOPLE_CONLMUSTARD, PEOPLE_PROFPLUM, PEOPLE_MISPEACOCK, PEOPLE_MISWHITE, PLACE_KITCHEN, PLACE_HALL, PLACE_POOLROOM, PLACE_STUDY, PLACE_LOUNG, PLACE_LIBRARY, PLACE_CONSERVATORY, PLACE_DINING, PLACE_BILLIARDS}; int deckSize = 23; // number of cards in allCards array int count; for (count = 0; count < deckSize; ++count) { printf(", %d", allCards[count]); } // End for // These three array's are so you can put a card back, if need be... int weaponCards[] = {WEAPON_ROPE, WEAPON_REVOLVER, WEAPON_LEADPIPE, WEAPON_CANDLESTICK, WEAPON_CANDLESTICK, WEAPON_KNIFE, WEAPON_WRENCH}; int weaponDeckSize = 7; int peopleCards[] = {PEOPLE_MRGREEN, PEOPLE_MSSCARLET, PEOPLE_CONLMUSTARD, PEOPLE_CONLMUSTARD, PEOPLE_PROFPLUM, PEOPLE_MISPEACOCK, PEOPLE_MISWHITE}; int peopleDeckSize = 7; int placeCards[] = {PLACE_KITCHEN, PLACE_HALL, PLACE_POOLROOM, PLACE_STUDY, PLACE_LOUNG, PLACE_LIBRARY, PLACE_CONSERVATORY, PLACE_DINING, PLACE_BILLIARDS}; int placeDeckSize = 9; srand(clock()); // seed rand() using clock() which gives // the current tick your processor is at... int killer[3]; // no need to initialize yet. killer[0-2] will initialize int deckShuffle = rand() % weaponDeckSize; // picks one number out of the deck killer[0] = weaponCards[deckShuffle]; allCards[deckShuffle] = 0; // Card drawn. No longer exists in deck deckShuffle = rand() % peopleDeckSize; // picks another random card out of the deck killer[1] = peopleCards[deckShuffle]; allCards[deckShuffle + weaponDeckSize] = 0; // Card drawn. No longer exists in deck deckShuffle = rand() % placeDeckSize; // randomly picks the last card needed killer[2] = placeCards[deckShuffle]; allCards[deckShuffle + weaponDeckSize + peopleDeckSize] = 0; // Card drawn. No longer exists in deck int numberOfCards = 0; printf("CLUE\n"); printf("written by John Schintone\n"); printf("Origonal game delvoped by Hasbro\n"); int numberOfPlayers = 0; while ((numberOfPlayers < 3) || (numberOfPlayers > 6)) { printf("How many players are Going to play :\n"); printf("[number] > "); scanf("%d",&numberOfPlayers); // A very fast if statement which only uses integers/char's switch(numberOfPlayers) { case 6: { numberOfCards = 3; } break; case 5: { numberOfCards = 4; } break; case 4: { numberOfCards = 5; } break; case 3: { numberOfCards = 6; } break; default: { printf("You must enter a number between 3 and 6...\n"); } // End default } // End switch } // End while int index1, index2; // Note: ++index1; is faster than index1++; and will almost always // produce better code (index1++ happens after this statement line. // ++index1 increments index1 before this statement line) for (index1 = 0; index1 < numberOfPlayers; ++index1) { printf("Player %d", index1); for (index2 = 0; index2 < numberOfCards; ++index2) { // Remember that allCards[deckShuffle] == 0 because we removed that // card ages ago... works out well, just don't forget you did that : ) while (allCards[deckShuffle] == 0) { deckShuffle = rand() % deckSize; } // End while players[index1][index2] = allCards[deckShuffle]; allCards[deckShuffle] = 0; // Card removed for after loop... printf(", %d", players[index1][index2]); switch(players[index1][index2]) { case WEAPON_ROPE: { } break; // Add more... case PEOPLE_MRGREEN: { } break; // Add more... case PLACE_KITCHEN: { } break; // Add more... default: { printf("Program has caught player %d cheating...", index1); } // End default } // End switch } // End for printf("\n"); } // End for printf("The killer is %d, with the %d, and in the %d \n\n", killer[0], killer[1], killer[2]); printf("Type h for this help... \n"); printf("Type e to escape... \n"); printf("Type r to roll the die... \n"); char command = '\0'; // \0 represents zero, or the null character while (command != 'e') { printf("[one character] > "); scanf("%c", &command); if (command == 'r') { die = rand() % 6 + 1; printf("Your number is: %d \n", die); } // end while if (command == 'h') { printf("Type h for this help... \n"); printf("Type e to escape... \n"); printf("Type r to roll the die... \n"); } // End if printf("\n"); } // End while return(0); // Success. Program worked ok } // End main() Function

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