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Lars Fosdal

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Posts posted by Lars Fosdal

  3. Posted

    @saeedbay Ref MARS - Don't explicitly set it to 'Yes'. Leave it to the driver default. 

      // Multiple Active Result Sets http://msdn.microsoft.com/en-us/library/ms131686.aspx
  if DisableMARS
   then Params.Values['MARS'] := 'No';

    Do you use threads?

    Do you call CoInitialize/CoUninitialize per thread?

    Do you exec your queries in the same thread as you create them?

    Do you reuse queries? Do you make sure to reuse them only in the thread they were created?

    Do you reuse the queries that are already in use? - Don't.

    Do you only do reads with the query? - Test if Query.FetchOptions.Unidirectional := True; gives you more speed.

     

    1 hour ago, saeedbay said:

    cannot make a visible windows modal

    Is the form created in the .dpr? Don't do that.   

    procedure TSomeParent.ShowTheForm;
begin
  var form := TYourForm.Create;
  // feed it with values if needed
  try
    if form.ShowModal = mrOK
    then ; // deal with the results if needed
  finally
    form.free;
  end
end;

    If you want to have only one instance of the form at a time, deal with that, f.x. with critical sections or similar.

     

    Do you use MadExcept or EurekaLog or similar? If not, you should - it really helps for pinpointing issues

  10. Posted

    @michel.seicon In theory, it could be related to

    Ref. https://stackoverflow.com/questions/48651432/glibc-application-holding-onto-unused-memory-until-just-before-exit

    Delphi memory manager on Linux wraps malloc, so the question then becomes - is it possible to invoke malloc_trim from Delphi for Linux?

     

    I suggest you clean up the test program to run correctly, and report it at https://qp.embarcadero.com with a proper description of the differences in behavior.

    That way we might get some information from EMBT.

  11. Posted

    It is compatible with all MS SQL servers. Currently using the same FireDAC integration with 2008, 2012, 2016,2017 and 2019.

     

    How do you parameterize your connection?

    Have you double checked that your query doesn't pull back a massive amount of data?

    Check the FireDAC Monitor to see if it offers any clues.

     

    Which driver are you using? I recommend using the ODBC drivers. 

    class function TPSDFireDatabasePoolMSSQL.FindBestDriver(const Link: TFDPhysMSSQLDriverLink): String;
const // Constants copied from implementation section of FireDAC.Phys.MSSQL
  C_SQL_SERVER = 'SQL Server'; // DO NOT TRANSLATE
  C_2019_ODBC = 'ODBC DRIVER 19 FOR SQL SERVER'; // DO NOT TRANSLATE
  C_2018_ODBC = 'ODBC DRIVER 18 FOR SQL SERVER'; // DO NOT TRANSLATE
  C_2017_ODBC = 'ODBC DRIVER 17 FOR SQL SERVER'; // DO NOT TRANSLATE
  C_2016_ODBC = 'ODBC DRIVER 13 FOR SQL SERVER'; // DO NOT TRANSLATE
  C_2012_ODBC = 'ODBC DRIVER 11 FOR SQL SERVER'; // DO NOT TRANSLATE
{$IFDEF POSIX}
  C_FreeTDS = 'FreeTDS'; // DO NOT TRANSLATE
{$ENDIF}
{$IFDEF MSWINDOWS}
  C_2012_NC = 'SQL SERVER NATIVE CLIENT 11.0'; // DO NOT TRANSLATE
{$ENDIF}
var
  DriverList : TStringList;
  WantedList : TArray<String>;
  Driver: string;
begin
  Result := ''; // Blank = Default

  WantedList := {$IFDEF MSWINDOWS}
                  {$IFDEF SQLNative}
                    [C_2012_NC, C_2017_ODBC, C_2016_ODBC, C_2012_ODBC]
                  {$ELSE}
                    [C_2018_ODBC, C_2017_ODBC, C_2016_ODBC, C_2012_NC, C_2012_ODBC]
                 {$ENDIF}
               {$ENDIF}
               {$IFDEF POSIX}
                 [C_2018_ODBC, C_2017_ODBC, C_2016_ODBC, C_2012_ODBC, C_FreeTDS]
               {$ENDIF};

  DriverList := TStringList.Create;
  try
    Link.GetDrivers(DriverList);

    DebugOut('Available SQL drivers'); // DO NOT TRANSLATE
    for Driver in DriverList
     do DebugOut(' "' + Driver + '"');

    for var Wanted in WantedList
     do for Driver in DriverList
      do begin
        if CompareText(Wanted , Driver) = 0
        then begin
          DebugOut('Selected driver: "' + Driver + '"'); // DO NOT TRANSLATE
          BestDriver := Driver;
          Exit(Driver);
        end;
      end;
  finally
    DriverList.Free;
  end;
end;

     

  15. Posted

    A workaround could be to explicitly allocate system memory outside of the regular memory manager, but that would require using specific methods for each platform.

    1 hour ago, DelphiUdIT said:

    EmptyWorkingSet(GetCurrentProcess)

    How does that work with memory allocations in FastMM?

  16. Posted

    The while true causes an infinte loop, which doesn't do anything but looping and sleeping after the first run, so why this can't run for days and days witout running out of memory, is a bit of a mystery.

    How do you monitor the memory usage?

     

    Building these fairly large strings will have the MemoryManager allocate memory blocks which will remain allocated (and reusable) after you free your classes. These will be allocated from system memory until the application exits. 

    In some corner cases, you can have memory fragmentation, which is caused by the elements in the list of released blocks of memory, being to small to be reused to hold the new objects, but in you example, that is not the issue.

     

    The line 

    TListaString(V_Listas[0]).V_String := '';

    is not necessary, as the string type is reference counted and automatically will be released.

    Apart from that,  I guess there is a point to why you are NOT using TStringList, but using other containers and methods in classes to encapsulate reused code, could greatly reduce the amount of code duplication - which again reduces the potential for errors.

    See System.Contnrs TObjectList and System.Generics.Collections TObjectList for examples of lists that can manage your objects.

     

    Tip - For the purpose of testing, you would want each time you test to be identical - hence setting RandSeed to a fixed value at the start will ensure you have repeatable execution.

     

  20. Posted

    56 minutes ago, Uwe Raabe said:
    1 hour ago, PeterPanettone said:

    Please VOTE & SHARE.

    The new QP doesn't support voting and I cannot see a benefit in sharing this.

    Well, sharing allows discovery, and those that are affected can add a comment?

    • Like 1

  24. Posted

    • Which language
    • Which version
    • Which class is SslHttpRest, and  from which unit?

    If you use System.Net.HttpClient (which I use, because getting the REST classes to work with various flavours of OAuth2 turned out to be a challenge), you can do it something like this (code is not complete 😞 

    var
  HTTPRequest: IHttpRequest; // from System.Net.HttpClient
  HttpResponse: IHttpResponse; // System.Net.HttpClient
  ReqHeaders: TNetHeaders; // System.Net.URLClient
  URL: String;
begin
  try
    try
      try
        HTTPRequest := HTTP.GetRequest('GET', URL);

        ReqHeaders := [
          TNetHeader.Create('Content-Type', 'application/json'),
          TNetHeader.Create('Content-Length, ''),
          TNetHeader.Create('Store-Token', '22345673301244567896663456789012'),
          TNetHeader.Create('User-Agent', 'PostmanRuntime/7.37.3'),
          TNetHeader.Create('Accept', '*/*'),
          TNetHeader.Create('Postman-Token', '40f28212-2f71-487a-a22f-d6ecdfa61b8b'),
          TNetHeader.Create('Host', 'localhost:8080'),
          TNetHeader.Create('Accept-Encoding', 'gzip, deflate, br'),
          TNetHeader.Create('Connection', 'keep-alive')
        ];

        HttpResponse := HTTP.Execute(HTTPRequest,nil, ReqHeaders); // HTTP is THTTPClient from System.Net.HttpClient
...

     

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