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Re: Threading... David Crow19-Jul-04 9:17 David Crow 19-Jul-04 9:17  dNimrod#X wrote: I have a worker thread being created at some point in my App. It happens that this [new] thread creates about 5 modeless dialogs... This raises a lot of red flags, namely that worker threads should not create UI components. If you must create a UI component in a thread other than the primary thread, it should be a UI thread (i.e., thread with a message pump). See here for more. "When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen Re: Threading... 0v3rloader19-Jul-04 22:53 0v3rloader 19-Jul-04 22:53  Hi, I've been reading on the subject and decided to follow your cue. You're absolutely right -- there is the need to have a message pump thread. Thanks very much for the reply. You have been very helpful indeed. David Database Application Performance Sridhar Sanikommu19-Jul-04 7:01 Sridhar Sanikommu 19-Jul-04 7:01  Hi, I'm developing a database application using CDatabase & CRecordSet classes. My SQL Server database is sitting on other machine and it's effecting application performance when I tried to insert large number of records and retrieving the records for generating some reports(i.e. to fetch 1000000 records at a time for creating a report). Application is getting too slow. Need some suggestions in this regard. Thanks, Re: Database Application Performance G. Steudtel19-Jul-04 7:10 G. Steudtel 19-Jul-04 7:10  Hi, probably instead of using mysql_store_result you should using mysql_use_result. It will give you a boost, but also a lot of drawbacks. See the C-API documentation for that. GSte Re: Database Application Performance Ivan Cachicatari19-Jul-04 7:12 Ivan Cachicatari 19-Jul-04 7:12  Hi, I recommend to segment this query or install more physics memory. navisoft www.latindevelopers.com Re: Database Application Performance Alexander Wiseman19-Jul-04 7:25 Alexander Wiseman 19-Jul-04 7:25  How are you using CRecordset? Are you predefining the query and the columns it returns with CRecordset, or are you simply creating a CRecordset from a query at run-time? If you are doing the former (predefining the query and the columns), there are some operations in which CRecordset performs very inefficient methods on the data, and it could be that the slowness you are seeing is because CRecordset is clogging the system memory. Check which way you are using CRecordset and also pull up Task Manager while your long query is running to see how much system memory it is sucking up. Sincerely, Alexander Wiseman Est melior esse quam videri It is better to be than to seem Re: Database Application Performance Sridhar Sanikommu19-Jul-04 7:35 Sridhar Sanikommu 19-Jul-04 7:35  Hi, I'm using the former one. I have to read a text file which has more than million records and insert each record at a time. Also, for genearting some reports, i've to fetch huge number of records at a time from the database and process all the records. Thanx, Re: Database Application Performance Alexander Wiseman19-Jul-04 10:14 Alexander Wiseman 19-Jul-04 10:14  So, just to clarify exactly what you are trying to do: you are opening and reading a text file from which data you want to insert records into a database. Because you want to insert so many records, I would suggest using a SQL command to insert the data (INSERT INTO...) instead of CRecordset::AddNew() and CRecordsSet::Update(). The CRecordset functions for adding records tend to be slower than simply executing a SQL statement against the database. You can execute a SQL statement by using the function in CDatabase (I forget the exact name, but it is something like "Execute"). For fetching large numbers of records, I would also suggest that you move away from the default RFX (Recordset Field Exchange - where you predefine the columns returned from the query) implemented with CRecordset. Again, this tends to be slower than simple qeurying the database with SQL statement and not using RFX. For some more information on this topic, take a look at the ODBC section on CodeProject: http://www.codeproject.com/database/#ODBC[^]. If you need more specific information, or some example code, please let me know. Sincerely, Alexander Wiseman Est melior esse quam videri It is better to be than to seem Re: Database Application Performance Sridhar Sanikommu19-Jul-04 11:28 Sridhar Sanikommu 19-Jul-04 11:28  Hi Alexander, Thanks for your input. Right now, I'm not using RFX for fetching the records nor AddNew() and Update() functions of CRecordset classes. As you said, i'm reading each record from the text file and create INSERT INTO.. query and execute it using CDatabase ExecuteSQL() function. However, for every call to this function, database has to parse , prepare an execution plan and compile it. Instead i'm thinking of using stored procedures. But my application has to support multipe databases like MSAccess, MySQl, Oracle & MS SQL Server. I don't think MSAccess supports Stored procedures and I'm not sure of MySQL either. Do you have any generic database module? If so, can you send it to me? I would appreciate your help. Thanx, Re: Database Application Performance Alexander Wiseman19-Jul-04 15:52 Alexander Wiseman 19-Jul-04 15:52  Hi Sridhar, Unfortunately, there won't be something which you can code which will take the place of a stored procedure for those DBs that don't support them. MySQL should have something you can use for optimization, although I thought it supported stored procedures. Maybe your best bet is to implement the insertion code inside a worker thread, so the main application UI doesn't seem like it isn't responding when you are doing the insert. Long operations, when necessary, are OK as long as you give the user some indication of what is actually happening and maybe a "Stop" button. Although I can't think of anything else right now, I will keep my eyes open for something that can help you. Sincerely, Alexander Wiseman Est melior esse quam videri It is better to be than to seem Re: Database Application Performance Anonymous19-Jul-04 16:36 Anonymous 19-Jul-04 16:36  Hi Alexander, I thought of implementing intensive database operations in the worker thread. Think this strategy will work for inserting records. But, what about fetching if you implement it in the worker thread? I mean, if my query is taking X number of sec or minutes to fetch Million plus records(Select * from table where condition). HOw do I cancel the worker thread if it's still in the process of retrieving? Some insight would be greatly appreciated. Thanks, Re: Database Application Performance Sridhar Sanikommu19-Jul-04 16:38 Sridhar Sanikommu 19-Jul-04 16:38  Hi Alexander, I thought of implementing intensive database operations in the worker thread. Think this strategy will work for inserting records. But, what about fetching if you implement it in the worker thread? I mean, if my query is taking X number of sec or minutes to fetch Million plus records(Select * from table where condition). HOw do I cancel the worker thread if it's still in the process of retrieving? Some insight would be greatly appreciated. Thanks, Sridhar Re: Database Application Performance Steen Krogsgaard19-Jul-04 23:01 Steen Krogsgaard 19-Jul-04 23:01  Hi, MSAccess (or rather Jet, the dbengine), supports stored procedures, at least it supports CREATE PROC and EXECUTE statements. See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnacc2k/html/acintsql.asp[^] Interestingly, this article on MSDN http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore/html/vcconstoredprocedures.asp[^] says that the OLEDB provider for Jet does not support stored procs, but it nevertheless works for me. Cheers Steen. "To claim that computer games influence children is ridiculous. If Pacman had influenced children born in the 80'ies we would see a lot of youngsters running around in dark rooms eating pills while listening to monotonous music" Finding files recursively Ivan Cachicatari19-Jul-04 6:55 Ivan Cachicatari 19-Jul-04 6:55  Hello everyone, I am searching the way to find for in archives and folders recursively. You can say me the optimal way to do it? Thanks! navisoft www.latindevelopers.com Re: Finding files recursively Alexander Wiseman19-Jul-04 7:21 Alexander Wiseman 19-Jul-04 7:21  Take a look at this article: http://www.codeproject.com/file/fileglob.asp[^], it implements exactly what you want and more. Hope that helps! Sincerely, Alexander Wiseman Est melior esse quam videri It is better to be than to seem Re: Finding files recursively gamitech19-Jul-04 12:07 gamitech 19-Jul-04 12:07  you can do a function like this int findfiles() { ... findfirstfile(*.*) if file=a directory findfile(directory) } gabby getting userID maggi198119-Jul-04 6:41 maggi1981 19-Jul-04 6:41  Hai, I'm working on win32 vc++.I want to get the user logon ID from the system and display it in my dialog(probably in a textbox).I dont know how to do that. Can anyone help pls. Thanks a lot in advance. Re: getting userID 19-Jul-04 7:06 19-Jul-04 7:06  Hi, You can obtain the current username writing follow code: DWORD userNameCharCount = 255; TCHAR userName[255]; if( !GetUserName( userName, &userNameCharCount) ){ // error! } CString str = userName; GetDlgItem(IDC_YOUREDIT_CTRL)->SetWindowText(str); navisoft www.latindevelopers.com problem with OnFileOpen toothpick19-Jul-04 6:31 toothpick 19-Jul-04 6:31  I am trying to create an OpenGL MDI application using Doc/View architecture. When the ID_FILE_NEW is handled, a child window with the correct openGL rendered scene appears. however when the ID_FILE_OPEN is handled by CWinApp:: OnFileOpen in the application, a 'VERIFY' in the following bit of code called causes an error. i am unable to determine why it occurs. BOOL CDocManager::DoPromptFileName(CString& fileName, UINT nIDSTitle, DWORD lFlags, BOOL bOpenFileDialog, CDocTemplate* pTemplate) { CFileDialog dlgFile(bOpenFileDialog); CString title; VERIFY(title.LoadString(nIDSTitle)); any help would be much appreciated. thanks. Re: problem with OnFileOpen PJ Arends19-Jul-04 7:22 PJ Arends 19-Jul-04 7:22  LoadString() has failed to load the string resource with the ID contained in nIDSTitle. Chances are you do not have that string in your string table. "You're obviously a superstar." - Christian Graus about me - 12 Feb '03 "Obviously ???  You're definitely a superstar!!!" mYkel - 21 Jun '04 Within you lies the power for good - Use it! Re: problem with OnFileOpen Antti Keskinen19-Jul-04 14:30 Antti Keskinen 19-Jul-04 14:30  Run your code in debug mode, and step through all function calls. Stepping allows you to see the parameters passed to the function, and simultaneously allows you to see the string table entries. If you encounter a situation where an invalid ID is passed to the function, try tracing back to see why it gets passed. -Antti Keskinen ---------------------------------------------- The definition of impossible is strictly dependant on what we think is possible. Re: problem with OnFileOpen toothpick20-Jul-04 12:56 toothpick 20-Jul-04 12:56  Thanks. i hadn't included "afxres.rc" in the resource file - that was causing the problem. i had included only "afxres.h" earlier. the trouble i am having now is that the child windows don't have a title. the resource string is fine - i used it in another program, it works ok. any comments would be most appreciated. thanks. File Mapping Toni7819-Jul-04 6:24 Toni78 19-Jul-04 6:24  If a file has been mapped with MapViewOfFile, will the offsets in memory correspond to the ones in the disk. For example if I try to access the contents at file offset 0x100 in the disk, after I map the file would I still be using offset 0x100 or will the memory alignment make the offset change. // Afterall, I realized that even my comment lines have bugs If the sun were to blow up, it would take us 7-8 minutes to realize it. Re: File Mapping bikram singh19-Jul-04 11:02 bikram singh 19-Jul-04 11:02  Toni78 wrote: will the offsets in memory correspond to the ones in the disk Yes, they will. However, ensure that either the whole file has been mapped, or the relevant portion that you want to access, has been mapped. Note that the "offset" must be added to the address returned by MapViewOfFile(). Optionally, MapViewOfFileEx() allows you to specify your own base address where the file will be "loaded". Memory alignment has to be taken into consideration when the file was opened with FILE_FLAG_NO_BUFFERING in the CreateFile() call. Bikram Singh Re: File Mapping Toni7821-Jul-04 8:47 Toni78 21-Jul-04 8:47  Thank you for your help. After I posted the question and I got no reply, I realized that I could test this by myself by loading the file and doing a byte compare with the file in the disk . At the end the files were identical so apparently there were no memory alignment issues. But I wasn't aware about FILE_FLAG_NO_BUFFERING . Either way, thank you again. // Afterall, I realized that even my comment lines have bugs If the sun were to blow up, it would take us 7-8 minutes to realize it.

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