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  • how to get mysql query as xml?

    - by mobibob
    I recall reading about XML support from MySql. Does anyone know how to get XML without writing code? My client-protocol expects XML and I have a data source that I can access from a web app (JSP using JDBC).

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  • Strange problem with MySQL full text query

    - by Manish
    This probably has something to do with my understanding of full text search or perhaps a known issue. My Java code creates search term for full text search on MySQL like this - +word* This works fine if the value in the DB column contains more text than the word itself. However, if the value is exact - no result are returned. I expected it to return results when value is an exact match. Let me give an example - Assume that DB has column name with value "Manish", now if I search with this - +Manis* It does return the result correctly, but if I try this - +Manish* It doesn't return any result, though exact match exists in DB column - Name. How can I obtain the desired behaviour in both these cases? Removing + sign works, but it returns far too many results when there are two or more words. Any help, pointers would be highly appreciated! I am using MySQL 5.0 TIA, - Manish

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  • Howto query arp table on iPhone?

    - by anthony vage
    Hi, i am new on iPhone development. I want to integrate wake on lan into my app without squeezing my users to enter the computers mac adress when the ip is already known. I googled for about some hours, take the source code of apples arp tool but i don't know howto manage this on iPhone. I am grateful for any help. Thanks! anthonyvage

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  • Advantage Database Server: slow stored procedure performance.

    - by ie
    I have a question about a performance of stored procedures in the ADS. I created a simple database with the following structure: CREATE TABLE MainTable ( Id INTEGER PRIMARY KEY, Name VARCHAR(50), Value INTEGER ); CREATE UNIQUE INDEX MainTableName_UIX ON MainTable ( Name ); CREATE TABLE SubTable ( Id INTEGER PRIMARY KEY, MainId INTEGER, Name VARCHAR(50), Value INTEGER ); CREATE INDEX SubTableMainId_UIX ON SubTable ( MainId ); CREATE UNIQUE INDEX SubTableName_UIX ON SubTable ( Name ); CREATE PROCEDURE CreateItems ( MainName VARCHAR ( 20 ), SubName VARCHAR ( 20 ), MainValue INTEGER, SubValue INTEGER, MainId INTEGER OUTPUT, SubId INTEGER OUTPUT ) BEGIN DECLARE @MainName VARCHAR ( 20 ); DECLARE @SubName VARCHAR ( 20 ); DECLARE @MainValue INTEGER; DECLARE @SubValue INTEGER; DECLARE @MainId INTEGER; DECLARE @SubId INTEGER; @MainName = (SELECT MainName FROM __input); @SubName = (SELECT SubName FROM __input); @MainValue = (SELECT MainValue FROM __input); @SubValue = (SELECT SubValue FROM __input); @MainId = (SELECT MAX(Id)+1 FROM MainTable); @SubId = (SELECT MAX(Id)+1 FROM SubTable ); INSERT INTO MainTable (Id, Name, Value) VALUES (@MainId, @MainName, @MainValue); INSERT INTO SubTable (Id, Name, MainId, Value) VALUES (@SubId, @SubName, @MainId, @SubValue); INSERT INTO __output SELECT @MainId, @SubId FROM system.iota; END; CREATE PROCEDURE UpdateItems ( MainName VARCHAR ( 20 ), MainValue INTEGER, SubValue INTEGER ) BEGIN DECLARE @MainName VARCHAR ( 20 ); DECLARE @MainValue INTEGER; DECLARE @SubValue INTEGER; DECLARE @MainId INTEGER; @MainName = (SELECT MainName FROM __input); @MainValue = (SELECT MainValue FROM __input); @SubValue = (SELECT SubValue FROM __input); @MainId = (SELECT TOP 1 Id FROM MainTable WHERE Name = @MainName); UPDATE MainTable SET Value = @MainValue WHERE Id = @MainId; UPDATE SubTable SET Value = @SubValue WHERE MainId = @MainId; END; CREATE PROCEDURE SelectItems ( MainName VARCHAR ( 20 ), CalculatedValue INTEGER OUTPUT ) BEGIN DECLARE @MainName VARCHAR ( 20 ); @MainName = (SELECT MainName FROM __input); INSERT INTO __output SELECT m.Value * s.Value FROM MainTable m INNER JOIN SubTable s ON m.Id = s.MainId WHERE m.Name = @MainName; END; CREATE PROCEDURE DeleteItems ( MainName VARCHAR ( 20 ) ) BEGIN DECLARE @MainName VARCHAR ( 20 ); DECLARE @MainId INTEGER; @MainName = (SELECT MainName FROM __input); @MainId = (SELECT TOP 1 Id FROM MainTable WHERE Name = @MainName); DELETE FROM SubTable WHERE MainId = @MainId; DELETE FROM MainTable WHERE Id = @MainId; END; Actually, the problem I had - even so light stored procedures work very-very slow (about 50-150 ms) relatively to plain queries (0-5ms). To test the performance, I created a simple test (in F# using ADS ADO.NET provider): open System; open System.Data; open System.Diagnostics; open Advantage.Data.Provider; let mainName = "main name #"; let subName = "sub name #"; // INSERT let cmdTextScriptInsert = " DECLARE @MainId INTEGER; DECLARE @SubId INTEGER; @MainId = (SELECT MAX(Id)+1 FROM MainTable); @SubId = (SELECT MAX(Id)+1 FROM SubTable ); INSERT INTO MainTable (Id, Name, Value) VALUES (@MainId, :MainName, :MainValue); INSERT INTO SubTable (Id, Name, MainId, Value) VALUES (@SubId, :SubName, @MainId, :SubValue); SELECT @MainId, @SubId FROM system.iota;"; let cmdTextProcedureInsert = "CreateItems"; // UPDATE let cmdTextScriptUpdate = " DECLARE @MainId INTEGER; @MainId = (SELECT TOP 1 Id FROM MainTable WHERE Name = :MainName); UPDATE MainTable SET Value = :MainValue WHERE Id = @MainId; UPDATE SubTable SET Value = :SubValue WHERE MainId = @MainId;"; let cmdTextProcedureUpdate = "UpdateItems"; // SELECT let cmdTextScriptSelect = " SELECT m.Value * s.Value FROM MainTable m INNER JOIN SubTable s ON m.Id = s.MainId WHERE m.Name = :MainName;"; let cmdTextProcedureSelect = "SelectItems"; // DELETE let cmdTextScriptDelete = " DECLARE @MainId INTEGER; @MainId = (SELECT TOP 1 Id FROM MainTable WHERE Name = :MainName); DELETE FROM SubTable WHERE MainId = @MainId; DELETE FROM MainTable WHERE Id = @MainId;"; let cmdTextProcedureDelete = "DeleteItems"; let cnnStr = @"data source=D:\DB\test.add; ServerType=local; user id=adssys; password=***;"; let cnn = new AdsConnection(cnnStr); try cnn.Open(); let cmd = cnn.CreateCommand(); let parametrize ix prms = cmd.Parameters.Clear(); let addParam = function | "MainName" -> cmd.Parameters.Add(":MainName" , mainName + ix.ToString()) |> ignore; | "SubName" -> cmd.Parameters.Add(":SubName" , subName + ix.ToString() ) |> ignore; | "MainValue" -> cmd.Parameters.Add(":MainValue", ix * 3 ) |> ignore; | "SubValue" -> cmd.Parameters.Add(":SubValue" , ix * 7 ) |> ignore; | _ -> () prms |> List.iter addParam; let runTest testData = let (cmdType, cmdName, cmdText, cmdParams) = testData; let toPrefix cmdType cmdName = let prefix = match cmdType with | CommandType.StoredProcedure -> "Procedure-" | CommandType.Text -> "Script -" | _ -> "Unknown -" in prefix + cmdName; let stopWatch = new Stopwatch(); let runStep ix prms = parametrize ix prms; stopWatch.Start(); cmd.ExecuteNonQuery() |> ignore; stopWatch.Stop(); cmd.CommandText <- cmdText; cmd.CommandType <- cmdType; let startId = 1500; let count = 10; for id in startId .. startId+count do runStep id cmdParams; let elapsed = stopWatch.Elapsed; Console.WriteLine("Test '{0}' - total: {1}; per call: {2}ms", toPrefix cmdType cmdName, elapsed, Convert.ToInt32(elapsed.TotalMilliseconds)/count); let lst = [ (CommandType.Text, "Insert", cmdTextScriptInsert, ["MainName"; "SubName"; "MainValue"; "SubValue"]); (CommandType.Text, "Update", cmdTextScriptUpdate, ["MainName"; "MainValue"; "SubValue"]); (CommandType.Text, "Select", cmdTextScriptSelect, ["MainName"]); (CommandType.Text, "Delete", cmdTextScriptDelete, ["MainName"]) (CommandType.StoredProcedure, "Insert", cmdTextProcedureInsert, ["MainName"; "SubName"; "MainValue"; "SubValue"]); (CommandType.StoredProcedure, "Update", cmdTextProcedureUpdate, ["MainName"; "MainValue"; "SubValue"]); (CommandType.StoredProcedure, "Select", cmdTextProcedureSelect, ["MainName"]); (CommandType.StoredProcedure, "Delete", cmdTextProcedureDelete, ["MainName"])]; lst |> List.iter runTest; finally cnn.Close(); And I'm getting the following results: Test 'Script -Insert' - total: 00:00:00.0292841; per call: 2ms Test 'Script -Update' - total: 00:00:00.0056296; per call: 0ms Test 'Script -Select' - total: 00:00:00.0051738; per call: 0ms Test 'Script -Delete' - total: 00:00:00.0059258; per call: 0ms Test 'Procedure-Insert' - total: 00:00:01.2567146; per call: 125ms Test 'Procedure-Update' - total: 00:00:00.7442440; per call: 74ms Test 'Procedure-Select' - total: 00:00:00.5120446; per call: 51ms Test 'Procedure-Delete' - total: 00:00:01.0619165; per call: 106ms The situation with the remote server is much better, but still a great gap between plaqin queries and stored procedures: Test 'Script -Insert' - total: 00:00:00.0709299; per call: 7ms Test 'Script -Update' - total: 00:00:00.0161777; per call: 1ms Test 'Script -Select' - total: 00:00:00.0258113; per call: 2ms Test 'Script -Delete' - total: 00:00:00.0166242; per call: 1ms Test 'Procedure-Insert' - total: 00:00:00.5116138; per call: 51ms Test 'Procedure-Update' - total: 00:00:00.3802251; per call: 38ms Test 'Procedure-Select' - total: 00:00:00.1241245; per call: 12ms Test 'Procedure-Delete' - total: 00:00:00.4336334; per call: 43ms Is it any chance to improve the SP performance? Please advice. ADO.NET driver version - 9.10.2.9 Server version - 9.10.0.9 (ANSI - GERMAN, OEM - GERMAN) Thanks!

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  • Implement System.Web.Caching.Cache Object in a controller to cache specific query

    - by Julien
    Hello World! I'm Julien and I have a question is it correct to implement my caching object like this in my controller : public class HomeController : BaseController { public static Cache cachingControl = new Cache(); ... And I Use it like this : public ActionResult Home() { IndexViewData view = new IndexViewData(); view.UserId = UserId; if (cachingControl.Get("viewHome") != null) { view = (IndexViewData)cachingControl.Get("viewHome"); } else { view.allAdsList = AllAds(5000, 0); if (Request.QueryString["voirTous"] != null) view.loadGeneral(true); else view.loadGeneral(false); cachingControl.Insert("viewHome", view); } view.adsList = SetupSearch(5, false, 0); return View(view); } But When I Call this line : if (cachingControl.Get("viewHome") != null) { They trow me the error NullErrorException But I know it can be null this is why i'm put this condition to Do you have an alternative or a tips for me thank you! P.S.: I Know that the code is weird :P but I must to support it ... Julien

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  • Django models query

    - by Hulk
    Code: class criteria(models.Model): details = models.CharField(max_length = 512) Headerid = models.ForeignKey(Header) def __unicode__(self): return self.id() the details corresponds to a textarea in the UI and a validation is done for 512 characters but when this is saved. /home/project/django/django/core/handlers/base.py in get_response, line 109 Is this any thing related with schema or number of characters entered from UI

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  • SQL Query problem: How to merge two lists.

    - by ProfK
    I have a base table of Participants and Answers, with the following structure: ParticipantId, BusUnitId, QuestionNum, Answer. In this table, QuestionNum ranges, say, from 1 to 6. I also have two other tables that sort of link QuestionNum to the actual question table, BusUnitQuestions, and ParticipantQuestions. For each QuestionNum, I must get the actual question text, based on QuestionId. BusUnitId, QuestionId ParticipantId, QuestionId Now assuming records with QuestionNum from 1 to 6. BusUnitQuestions has 3 records, so QuestionNum 1 to 3 must join to Question on the QuestionId's from BusUnitQuestions, and QuestionNum 4 to 6 must join to Question on the QuestionId's from ParticipantQuestions. I assume I need to use ROW_NUMBER() in the subquery from BusUnitQuestions to join to my answer table, but I'm lost after that. If anyone at all understands me, do you have any suggestions?

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  • using distinct in django query

    - by Hulk
    There is a column as designation in the defaults table,How to get the distinct designation values from defaults table In the below the distinct applies on the id field, this need to be on designation field def = defaults.objects.filter(name=sc).distinct() And can some one explain what is flat=true condition Thanks..

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  • Regex negative match query

    - by Matt
    Hey guys, I've got a regex issue, Im trying to ignore just the number '41', I want 4, 1, 14 etc to all match. I've got this [^\b41\b] which is effectively what I want but this also ignores all single iterations of the values 1 and 4. As an example, this matches "41", but I want it to NOT match: \b41\b

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  • how to catch ajax query post error?

    - by TTCG
    I would like to catch the error and show the appropriate message if the ajax request fails. My code is like the following, but I could not manage to catch the failure ajax request. function getAjaxData(id) { $.post("status.ajax.php", {deviceId : id}, function(data){ var tab1; if (data.length>0) { tab1 = data; } else { tab1 = "Error in Ajax"; } return tab1; }); } I found out that, "Error in Ajax" is never executed when the Ajax request failed. How to handle the ajax error and show the appropriate message if it fails? Thanks very much.

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  • Linq Query to Update Nested Array Items?

    - by Brett
    I have an object structure generated from xsd.exe. Roughly, it consists of 3 nested arrays: protocols, sources and reports. The xml looks like this: <protocols> <protocol> <source> <report /> <report /> </source> <source> <report /> <report /> </source> </protocol> <!-- more protocols --> </protocols> I need to update a single "Report" within the data structure. A brute force algorithm is shown below. I know that this could be done using XDocument and Linq, but I'd prefer to update the data structure and then serialize the structure back to disk. Thoughts? Brett bool updated = false; foreach (ProtocolsProtocol protocol in protocols.Protocol) { if (updated) break; foreach (ProtocolsProtocolSource source in protocol.Source) { if (updated) break; for (int i = 0; i < source.Report.Length; i++) { ProtocolsProtocolSourceReport currentReport = source.Report[i]; if (currentReport.Id == report.Id) { currentReport.Attribute1 = report.Attribute1; currentReport.Attribute2 = report.Attribute2; updated = true; break; } } } }

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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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  • Force creation of query execution plan

    - by Marc
    I have the following situation: .net 3.5 WinForm client app accessing SQL Server 2008 Some queries returning relatively big amount of data are used quite often by a form Users are using local SQL Express and restarting their machines at least daily Other users are working remotely over slow network connections The problem is that after a restart, the first time users open this form the queries are extremely slow and take more or less 15s on a fast machine to execute. Afterwards the same queries take only 3s. Of course this comes from the fact that no data is cached and must be loaded from disk first. My question: Would it be possible to force the loading of the required data in advance into SQL Server cache? Note My first idea was to execute the queries in a background worker when the application starts, so that when the user starts the form the queries will already be cached and execute fast directly. I however don't want to load the result of the queries over to the client as some users are working remotely or have otherwise slow networks. So I thought just executing the queries from a stored procedure and putting the results into temporary tables so that nothing would be returned. Turned out that some of the result sets are using dynamic columns so I couldn't create the corresponding temp tables and thus this isn't a solution. Do you happen to have any other idea?

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  • any command line com port query tools?

    - by c_programmer
    ok folks, heres my dilemma i want to make a chat program that uses sms as its base engine.. to do this i need to communicate with my gsm phone via bluetooth attached to com 7 on my computer.. i can do this fine using hyperterminal, tera term etc. but to hav an un-obtrusive, friendly interface i need a command line tool to send AT commands, (and receive responses) to/from my mobile phone through my com port.. i have been searching for days to no avail.. please help

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  • query about xml parsing

    - by shishir.bobby
    hi all ,i just want to knw,is there any boundations in xml parsing with characters like can we parse a word containing some characters like "frühe" containing "ü" "böser" containing "ö" while i am parsing my xml,which is few different languages, some characters are like the above. and wen i saw in console, it get interpted,exaactly wen it reacher "ü" becoz at console it prints "fr" so can someone provide me some ideas about this thing regards shishir

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  • jQuery won't parse my JSON from AJAX query

    - by littlecharva
    Hi, I'm having difficulty parsing some JSON data returned from my server using jQuery.ajax() To perform the AJAX I'm using: $.ajax({ url: myUrl, cache: false, dataType: "json", success: function(data){ ... }, error: function(e, xhr){ ... } }); And if I return an array of items then it works fine: [ { title: "One", key: "1" }, { title: "Two", key: "2" } ] The success function is called and receives the correct object. However, when I'm trying to return a single object: { title: "One", key: "1" } The error function is called and xhr contains 'parsererror'. I've tried wrapping the JSON in parenthesis on the server before sending it down the wire, but it makes no difference. Yet if I paste the content into a string in Javascript and then use the eval() function, it evaluates it perfectly. Any ideas what I'm doing wrong? Anthony

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  • Query on simple C++ threadpool implementation

    - by ticketman
    Stackoverflow has been a tremendous help to me and I'd to give something back to the community. I have been implementing a simple threadpool using the tinythread C++ portable thread library, using what I have learnt from Stackoverflow. I am new to thread programming, so not that comfortable with mutexes, etc. I have a question best asked after presenting the code (which runs quite well under Linux): // ThreadPool.h class ThreadPool { public: ThreadPool(); ~ThreadPool(); // Creates a pool of threads and gets them ready to be used void CreateThreads(int numOfThreads); // Assigns a job to a thread in the pool, but doesn't start the job // Each SubmitJob call will use up one thread of the pool. // This operation can only be undone by calling StartJobs and // then waiting for the jobs to complete. On completion, // new jobs may be submitted. void SubmitJob( void (*workFunc)(void *), void *workData ); // Begins execution of all the jobs in the pool. void StartJobs(); // Waits until all jobs have completed. // The wait will block the caller. // On completion, new jobs may be submitted. void WaitForJobsToComplete(); private: enum typeOfWorkEnum { e_work, e_quit }; class ThreadData { public: bool ready; // thread has been created and is ready for work bool haveWorkToDo; typeOfWorkEnum typeOfWork; // Pointer to the work function each thread has to call. void (*workFunc)(void *); // Pointer to work data void *workData; ThreadData() : ready(false), haveWorkToDo(false) { }; }; struct ThreadArgStruct { ThreadPool *threadPoolInstance; int threadId; }; // Data for each thread ThreadData *m_ThreadData; ThreadPool(ThreadPool const&); // copy ctor hidden ThreadPool& operator=(ThreadPool const&); // assign op. hidden // Static function that provides the function pointer that a thread can call // By including the ThreadPool instance in the void * parameter, // we can use it to access other data and methods in the ThreadPool instance. static void ThreadFuncWrapper(void *arg) { ThreadArgStruct *threadArg = static_cast<ThreadArgStruct *>(arg); threadArg->threadPoolInstance->ThreadFunc(threadArg->threadId); } // The function each thread calls void ThreadFunc( int threadId ); // Called by the thread pool destructor void DestroyThreadPool(); // Total number of threads available // (fixed on creation of thread pool) int m_numOfThreads; int m_NumOfThreadsDoingWork; int m_NumOfThreadsGivenJobs; // List of threads std::vector<tthread::thread *> m_ThreadList; // Condition variable to signal each thread has been created and executing tthread::mutex m_ThreadReady_mutex; tthread::condition_variable m_ThreadReady_condvar; // Condition variable to signal each thread to start work tthread::mutex m_WorkToDo_mutex; tthread::condition_variable m_WorkToDo_condvar; // Condition variable to signal the main thread that // all threads in the pool have completed their work tthread::mutex m_WorkCompleted_mutex; tthread::condition_variable m_WorkCompleted_condvar; }; cpp file: // // ThreadPool.cpp // #include "ThreadPool.h" // This is the thread function for each thread. // All threads remain in this function until // they are asked to quit, which only happens // when terminating the thread pool. void ThreadPool::ThreadFunc( int threadId ) { ThreadData *myThreadData = &m_ThreadData[threadId]; std::cout << "Hello world: Thread " << threadId << std::endl; // Signal that this thread is ready m_ThreadReady_mutex.lock(); myThreadData->ready = true; m_ThreadReady_condvar.notify_one(); // notify the main thread m_ThreadReady_mutex.unlock(); while(true) { //tthread::lock_guard<tthread::mutex> guard(m); m_WorkToDo_mutex.lock(); while(!myThreadData->haveWorkToDo) // check for work to do m_WorkToDo_condvar.wait(m_WorkToDo_mutex); // if no work, wait here myThreadData->haveWorkToDo = false; // need to do this before unlocking the mutex m_WorkToDo_mutex.unlock(); // Do the work switch(myThreadData->typeOfWork) { case e_work: std::cout << "Thread " << threadId << ": Woken with work to do\n"; // Do work myThreadData->workFunc(myThreadData->workData); std::cout << "#Thread " << threadId << ": Work is completed\n"; break; case e_quit: std::cout << "Thread " << threadId << ": Asked to quit\n"; return; // ends the thread } // Now to signal the main thread that my work is completed m_WorkCompleted_mutex.lock(); m_NumOfThreadsDoingWork--; // Unsure if this 'if' would make the program more efficient // if(NumOfThreadsDoingWork == 0) m_WorkCompleted_condvar.notify_one(); // notify the main thread m_WorkCompleted_mutex.unlock(); } } ThreadPool::ThreadPool() { m_numOfThreads = 0; m_NumOfThreadsDoingWork = 0; m_NumOfThreadsGivenJobs = 0; } ThreadPool::~ThreadPool() { if(m_numOfThreads) { DestroyThreadPool(); delete [] m_ThreadData; } } void ThreadPool::CreateThreads(int numOfThreads) { // Check a thread pool has already been created if(m_numOfThreads > 0) return; m_NumOfThreadsGivenJobs = 0; m_NumOfThreadsDoingWork = 0; m_numOfThreads = numOfThreads; m_ThreadData = new ThreadData[m_numOfThreads]; ThreadArgStruct threadArg; for(int i=0; i<m_numOfThreads; ++i) { threadArg.threadId = i; threadArg.threadPoolInstance = this; // Creates the thread and save in a list so we can destroy it later m_ThreadList.push_back( new tthread::thread( ThreadFuncWrapper, (void *)&threadArg ) ); // It takes a little time for a thread to get established. // Best wait until it gets established before creating the next thread. m_ThreadReady_mutex.lock(); while(!m_ThreadData[i].ready) // Check if thread is ready m_ThreadReady_condvar.wait(m_ThreadReady_mutex); // If not, wait here m_ThreadReady_mutex.unlock(); } } // Adds a job to the batch, but doesn't start the job void ThreadPool::SubmitJob(void (*workFunc)(void *), void *workData) { // Check that the thread pool has been created if(!m_numOfThreads) return; if(m_NumOfThreadsGivenJobs >= m_numOfThreads) return; m_ThreadData[m_NumOfThreadsGivenJobs].workFunc = workFunc; m_ThreadData[m_NumOfThreadsGivenJobs].workData = workData; std::cout << "Submitted job " << m_NumOfThreadsGivenJobs << std::endl; m_NumOfThreadsGivenJobs++; } void ThreadPool::StartJobs() { // Check that the thread pool has been created // and some jobs have been assigned if(!m_numOfThreads || !m_NumOfThreadsGivenJobs) return; // Set 'haveworkToDo' flag for all threads m_WorkToDo_mutex.lock(); for(int i=0; i<m_NumOfThreadsGivenJobs; ++i) m_ThreadData[i].haveWorkToDo = true; m_NumOfThreadsDoingWork = m_NumOfThreadsGivenJobs; // Reset this counter so we can resubmit jobs later m_NumOfThreadsGivenJobs = 0; // Notify all threads they have work to do m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); } void ThreadPool::WaitForJobsToComplete() { // Check that a thread pool has been created if(!m_numOfThreads) return; m_WorkCompleted_mutex.lock(); while(m_NumOfThreadsDoingWork > 0) // Check if all threads have completed their work m_WorkCompleted_condvar.wait(m_WorkCompleted_mutex); // If not, wait here m_WorkCompleted_mutex.unlock(); } void ThreadPool::DestroyThreadPool() { std::cout << "Ask threads to quit\n"; m_WorkToDo_mutex.lock(); for(int i=0; i<m_numOfThreads; ++i) { m_ThreadData[i].haveWorkToDo = true; m_ThreadData[i].typeOfWork = e_quit; } m_WorkToDo_condvar.notify_all(); m_WorkToDo_mutex.unlock(); // As each thread terminates, catch them here for(int i=0; i<m_numOfThreads; ++i) { tthread::thread *t = m_ThreadList[i]; // Wait for thread to complete t->join(); } m_numOfThreads = 0; } Example of usage: (this calculates pi-squared/6) struct CalculationDataStruct { int inputVal; double outputVal; }; void LongCalculation( void *theSums ) { CalculationDataStruct *sums = (CalculationDataStruct *)theSums; int terms = sums->inputVal; double sum; for(int i=1; i<terms; i++) sum += 1.0/( double(i)*double(i) ); sums->outputVal = sum; } int main(int argc, char** argv) { int numThreads = 10; // Create pool ThreadPool threadPool; threadPool.CreateThreads(numThreads); // Create thread workspace CalculationDataStruct sums[numThreads]; // Set up jobs for(int i=0; i<numThreads; i++) { sums[i].inputVal = 3000*(i+1); threadPool.SubmitJob(LongCalculation, &sums[i]); } // Run the jobs threadPool.StartJobs(); threadPool.WaitForJobsToComplete(); // Print results for(int i=0; i<numThreads; i++) std::cout << "Sum of " << sums[i].inputVal << " terms is " << sums[i].outputVal << std::endl; return 0; } Question: In the ThreadPool::ThreadFunc method, would better performance be obtained if the following if statement if(NumOfThreadsDoingWork == 0) was included? Also, I'd be grateful of criticisms and ways to improve the code. At the same time, I hope the code is of use to others.

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  • How to make custom join query with Django ?

    - by xRobot
    I have these 2 models: genre = ( ('D', 'Dramatic'), ('T', 'Thriller'), ('L', 'Love'), ) class Book(models.Model): title = models.CharField(max_length=100) genre = models.CharField(max_length=1, choices=genre) class Author(models.Model): user = models.ForeignKey(User, unique=True) born = models.DateTimeField('born') book = models.ForeignKey(Book) I need to retrieve first_name and last_name of all authors of dramatic's books. How can I do this in django ?

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  • request query convert from vb to c#

    - by hossam
    this code is made by vb,page name:main.aspx when i type the url like that main.aspx?sStyle=0 it type word Yes in the page and if i type the url like that main.aspx?sStyle=0 it type word No in the page <%@ Page Language=VB Debug=true %> <% Dim sStyle If Request.QueryString("sStyle") = "0" Or Len(Request.QueryString("sStyle")) = 0 Then Me = 0 ElseIf Request.QueryString("sStyle") = "1" Then Me = 1 End If %> <%If sStyle = "0" Then%> Yes <%End If%> <%If sStyle = "1" Then%> No <%End If%> ========================================================= my question is how do i make the exact same page using c# Regards

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  • LINQ Query Problem

    - by Ritz
    I want to use this in my application but I'm getting an error for GetByLatest().Cast<IRss>(); Please suggest a solution IList<IRss> news = new Trytable().GetByLatest().Cast<IRss>(); return new RssResult(news, "William Duffy - Glasgow Based ASP.NET Web Developer", "The latest news on ASP.NET, C# and ASP.NET MVC ");

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