djxandytche

Thanks for the tip. I will create a singleton for the TPythonModule and TPyDelphiWrapper classes. Thanks also for the document that talks about working with threads. I had already implemented the same code here that exists in the TPythonThread class. For each request that arrives at the DataSnap server I call this method at the beginning: procedure InitializePythonThread; begin if PythonOK then with GetPythonEngine do begin zGilState := PyGILState_Ensure; try zGlobalThreadState := PyThreadState_Get; try PyThreadState_Swap(nil); zThreadState := Py_NewInterpreter; if not Assigned(zThreadState) then raise EPythonError.Create( 'Could not create a new thread state'); PyThreadState_Swap(zThreadState); zPythonThreadInitialized := True; except PyThreadState_Swap(zGlobalThreadState); raise; end; except PyGILState_Release(zGilState); raise; end; end; end; And I call this method at the end: procedure FinalizePythonThread; begin if zPythonThreadInitialized and PythonOK then with GetPythonEngine do begin Py_EndInterpreter(zThreadState); PyThreadState_Swap(zGlobalThreadState); PyGILState_Release(zGilState); end; end; Here is the complete code I created to create and destroy the global TPythonEngine instance on DataSnap server startup and termination. And the thread initialization and termination part as well: unit UnitPythonUtils; interface uses Data.DB, Variants, System.SysUtils, System.DateUtils, Fe.Value, Vcl.StdCtrls; procedure InitializePythonEngineIfNecessaryAndIfPossible; procedure FinalizePythonEngine; threadvar zPythonThreadInitialized: Boolean; procedure InitializePythonThread; procedure FinalizePythonThread; implementation uses PythonVersions, PythonEngine, UnitGeneralHelpers, System.JSON, UnitStreams, Data.FMTBcd, UnitStringManager, UnitDialogs, UnitFormPythonInstallation, Vcl.Controls; var zMainThreadState: PPyThreadState; threadvar zGilState: PyGILState_STATE; zThreadState: PPyThreadState; zGlobalThreadState: PPyThreadState; procedure InitializePythonEngineIfNecessaryAndIfPossible; var zPythonVersion: TPythonVersion; begin // Primeiro verifico se o Python já está inicializado. if PythonOK then Exit; if GetLatestRegisteredPythonVersion(zPythonVersion) then with TPythonEngine.Create(nil) do try AutoLoad := False; zPythonVersion.AssignTo(ThisEx); LoadDLL; // Isso configura o engine do Python para permitir multithread no Delphi. zMainThreadState := PyEval_SaveThread; except // TODO: Será que precisa fazer um log do erro que der aqui?? Free; end; end; procedure FinalizePythonEngine; var zPythonEngine: TPythonEngine; begin // Primeiro verifico se o Python está inicializado. // Pode ser que não foi possível inicializa-lo (se não estiver instalado por exemplo). if not PythonOK then Exit; zPythonEngine := GetPythonEngine; zPythonEngine.PyEval_RestoreThread(zMainThreadState); { será que precisa disso?? } FreeAndNil(zPythonEngine); end; procedure InitializePythonThread; begin if PythonOK then with GetPythonEngine do begin zGilState := PyGILState_Ensure; try zGlobalThreadState := PyThreadState_Get; try PyThreadState_Swap(nil); zThreadState := Py_NewInterpreter; if not Assigned(zThreadState) then raise EPythonError.Create( 'Could not create a new thread state'); PyThreadState_Swap(zThreadState); zPythonThreadInitialized := True; except PyThreadState_Swap(zGlobalThreadState); raise; end; except PyGILState_Release(zGilState); raise; end; end; end; procedure FinalizePythonThread; begin if zPythonThreadInitialized and PythonOK then with GetPythonEngine do begin Py_EndInterpreter(zThreadState); PyThreadState_Swap(zGlobalThreadState); PyGILState_Release(zGilState); end; end; end. This way, the DataSnap request thread will have the same as the TPythonThread. So far everything has worked correctly with multi-threds.

Hello, I'm using python4delphi on a REST backend developed with DataSnap. Each incoming request creates instances of TPythonModule and TPyDelphiWrapper, executes the Python script and destroys the instances when the request thread ends. Just the instance of PythonEnginand I create it once at the backend service startup and reuse it in requests. Do you have any recommendations for this use case? Maybe create any instance just to always have an active client? If so, which class instance would be most appropriate? Or perhaps create a singleton for the TPythonModule and TPyDelphiWrapper classes? Wouldn't this cause problems with multi-threads since the DataSnap server can receive several requests at the same time? Thank you again.

Hello, I would like help again. In a code I created here, the TPythonEngine instance is being terminated automatically. But, I wish that didn't happen. I tried assigning False to the TPythonEngine.AutoFinalize property, but it didn't help. I created this small example to reproduce the case: procedure TForm1.Button1Click(Sender: TObject); var zMemTable: TFDMemTable; zPythonModule: TPythonModule; zPyDelphiWrapper: TPyDelphiWrapper; pyObj: PPyObject; const ctPythonScript = 'import DBFireDac' + sLineBreak + sLineBreak + 'dataset = DBFireDac.FDMemTable' + sLineBreak + sLineBreak + 'dataset.Append()' + sLineBreak + 'dataset.FieldByName(''id'').AsInteger = 1' + sLineBreak + 'dataset.FieldByName(''name'').AsString = ''name 1''' + sLineBreak + sLineBreak + 'dataset.Append()' + sLineBreak + 'dataset.FieldByName(''id'').AsInteger = 2' + sLineBreak + 'dataset.FieldByName(''name'').AsString = ''name 2'''; begin zMemTable := TFDMemTable.Create(nil); with zMemTable do try with FieldDefs.AddFieldDef do begin Name := 'id'; DataType := ftInteger; end; with FieldDefs.AddFieldDef do begin Name := 'name'; DataType := ftString; end; Open; BeginBatch; zPythonModule := TPythonModule.Create(nil); try with zPythonModule do begin Engine := GetPythonEngine; ModuleName := 'DBFireDac'; Initialize; end; zPyDelphiWrapper := TPyDelphiWrapper.Create(nil); try with zPyDelphiWrapper do begin Engine := GetPythonEngine; Module := zPythonModule; Initialize; pyObj := Wrap(zMemTable); end; zPythonModule.SetVar('FDMemTable', pyObj); with GetPythonEngine do begin Py_XDecRef(pyObj); ExecString(UTF8Encode(ctPythonScript)); end; finally zPyDelphiWrapper.Free; end; finally zPythonModule.Free; { at this point the PythonEngine instance is finalized automatically: TPythonEngine.Finalize is called because ClientCount=0 } end; EndBatch; First; while not Eof do begin ShowMessage(FieldByName('id').AsInteger.ToString + ': ' + FieldByName('name').AsString); Next; end; finally Free; end; end; When I click the button for the first time, the code runs correctly. When I click the button for the second time, the error below occurs: Is there any way for the TPythonEngine instance not to be terminated automatically? Note: The complete example project is attached. Thanks, Alexandre da Silva. Project1.zip

That was it! I updated, tested and now the memory leak no longer occurs. Thank you for your help!

Hi, Do you mean capturing the output via "TPythonGUIInputOutput"? If so: I'm not even using it. I've made the code as simple as possible. See below: Unit1.pas: unit Unit1; interface uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, PythonEngine; type TForm1 = class(TForm) PythonEngine1: TPythonEngine; Memo1: TMemo; Button1: TButton; Label1: TLabel; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} procedure TForm1.Button1Click(Sender: TObject); var i: Integer; begin for i := 1 to 1000 do GetPythonEngine.ExecString('print("hello")'); end; end. Unit1.dfm: object Form1: TForm1 Left = 0 Top = 0 Caption = 'Form1' ClientHeight = 234 ClientWidth = 351 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -12 Font.Name = 'Segoe UI' Font.Style = [] TextHeight = 15 object Label1: TLabel Left = 8 Top = 8 Width = 73 Height = 15 Caption = 'Python script:' end object Memo1: TMemo Left = 8 Top = 29 Width = 185 Height = 89 Lines.Strings = ( 'print("hello")') TabOrder = 0 end object Button1: TButton Left = 8 Top = 124 Width = 185 Height = 25 Caption = 'Run 1000 times' TabOrder = 1 OnClick = Button1Click end object PythonEngine1: TPythonEngine Left = 112 Top = 48 end end Is there something else I could be doing wrong?

Hello, First of all I'd like to congratulate you on the excellent work you've done on P4D. Secondly, I want to apologize for my bad English (I'm Brazilian and I'm using Google Translate to help). I'm studying and testing P4D and I came across a situation that I couldn't understand. The situation is a memory leak that occurs whenever the "ExecString" method is called to execute any script. To simulate it, just do this simple example: procedure TForm1.Button1Click(Sender: TObject); var i: Integer; begin for i := 1 to 1000 do GetPythonEngine.ExecString('print("hello")'); end; I'm using Delphi 11.1 and compiling for 64-bit Windows. For every 1000 scripts executed, memory consumption increases by about 0.5 MB. In software that runs 100000 scripts per day, memory consumption could increase by around 50 MB per day. I intend to use P4D in the software of the company I work for and in most cases it will exceed 100000 scripts executed per day and the executable will be running 24x7. Considering this, I believe that at some point the memory may reach its limit. Is there anything I can do to free up the memory consumed by each call to the "ExecString" method? Thanks, Alexandre da Silva.