Error Creating a "TIBCConnection" inside a Thread.

Discussion of open issues, suggestions and bugs regarding IBDAC (InterBase Data Access Components) for Delphi, C++Builder, Lazarus (and FPC)
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luapfr
Posts: 28
Joined: Thu 11 Apr 2013 13:11

Error Creating a "TIBCConnection" inside a Thread.

Post by luapfr » Wed 08 May 2019 00:36

to be able to take advantage of a Connection with the Database I created a class called "TConnectionThread"

That way I do not declare the "TIBCConnection" within the Thread Class however I create the "TIBCConnection" Inside the Thread

And give me an error of "EIBCError" -> "unable to allocate memory from operating system"

The problem is that this is random and I can not reproduce in my machine this problem only happened in some clients where I put a system of Tests.

The link for you to download the Sample Sources is this:

https://mega.nz/#!EjoFWQBb!AOsqz_x3etGZ ... Dg20VjJzUA

in this example I did not put the database you can put any database with a Query that swallows multiple records to be Slow.

Code: Select all


uses
 Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
 Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Data.DB, Vcl.Grids, Vcl.DBGrids,
 DBAccess, IBC, MemDS, Vcl.StdCtrls, Vcl.ExtCtrls;

type
 TForm1 = class(TForm)
  IBCQuery2: TIBCQuery;
  DataSource2: TDataSource;
  DataSource1: TDataSource;
  IBCQuery1: TIBCQuery;
  IBCConnection1: TIBCConnection;
  DBGrid1: TDBGrid;
  DBGrid2: TDBGrid;
  Button3: TButton;
  Button4: TButton;
  IBCConnection2: TIBCConnection;
  procedure FormCreate(Sender: TObject);
  procedure Button3Click(Sender: TObject);
  procedure Button4Click(Sender: TObject);
 private
  { Private declarations }
 public
  { Public declarations }
 end;

Type
 TConnectionThread = Class
 Public
  emUso: Boolean;
  fIBConnection: TIBCConnection;
  constructor Create;
 End;

type
 TThreadQuery = class(TThread)
 private
  IndexConn: Integer;
  fQuery: TIBCQuery;

  procedure Proc_Termino(Sender: TObject);
 protected
  procedure Execute; override;
 public
  fForm: TForm;
  constructor Create(aQuery: TIBCQuery; aForm: TForm);
 end;

var
 Form1: TForm1;
 fConnectionThread: TConnectionThread;
 FListConnection: TList;
 IndexObj: Integer;
 StrErroQuery: String;
 QuerythrSQL: TThreadQuery;

implementation

{$R *.dfm}


Uses
 Unit_TempoCDS;

constructor TConnectionThread.Create;
begin
 inherited Create;

 fIBConnection := TIBCConnection.Create(Nil);

 With fIBConnection, Form1 do Begin
  Database := IBCConnection1.Database;
  UserName := IBCConnection1.UserName;
  Password := IBCConnection1.Password;
  SQLDialect := IBCConnection1.SQLDialect;
  ClientLibrary := IBCConnection1.ClientLibrary;
  Options.Protocol := IBCConnection1.Options.Protocol;
  Options.DisconnectedMode := True;
  LoginPrompt := False;
  Connected := True;
 End;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 FListConnection := TList.Create;

end;

constructor TThreadQuery.Create(aQuery: TIBCQuery; aForm: TForm);
begin
 inherited Create(False);

 fQuery := aQuery;
 fForm := aForm;

 OnTerminate := Proc_Termino;
 FreeOnTerminate := True;

end;

Function GetConnectioninThread(Var IndexConn: Integer): TIBCConnection;
Var I: Integer;
Var AchouConnection: Boolean;
Begin
 IndexConn := -1;
 AchouConnection := False;

 For I := 0 to FListConnection.count - 1 do begin

  if Not TConnectionThread(FListConnection[I]).emUso Then Begin
   AchouConnection := True;

   Result := TConnectionThread(FListConnection[I]).fIBConnection;

   TConnectionThread(FListConnection[I]).emUso := True;
   IndexConn := I;
   Break;
  End;

 End;

 if Not AchouConnection Then Begin
  fConnectionThread := TConnectionThread.Create; [b]// Error  "EIBCError"  unable to allocate memory from operating system[/b]
  
  FListConnection.Add(fConnectionThread);

  IndexConn := FListConnection.count - 1;

  Result := fConnectionThread.fIBConnection;

  fConnectionThread.emUso := True;
 End;

End;


procedure TThreadQuery.Execute;
Var vSQL: String;
begin
 Try
  StrErroQuery := EmptyStr;

  fQuery.Close;

  vSQL := fQuery.Sql.Text;

  fQuery.Connection := GetConnectioninThread(IndexConn);

  fQuery.Open;

 Except
  on E: Exception do begin

   Raise Exception.Create(E.Message + #13#13 + vSQL);

  end;
 End;

end;

procedure TThreadQuery.Proc_Termino(Sender: TObject);
Var NameForm: String;
begin
 if Assigned(fForm) Then
  fForm.Close;

 if IndexConn > -1 Then
  TConnectionThread(FListConnection[IndexConn]).emUso := False;

 QuerythrSQL := Nil;

end;


Function Func_OpenCDS(aQuery: TIBCQuery; Tabela: String): Boolean;
Var vDataSet: TDataSet;

 Procedure Proc_ShowProgressTabela;
 Begin
   Frm_TempoCDS := TFrm_TempoCDS.Create(Nil);

   Frm_TempoCDS.Lb_Mensagem.Caption := Tabela;
   Frm_TempoCDS.Lb_Mensagem.Update;

   Frm_TempoCDS.Show;
   Frm_TempoCDS.Update;

   QuerythrSQL := TThreadQuery.Create(aQuery, Frm_TempoCDS);

   While (Assigned(QuerythrSQL)) And (Not QuerythrSQL.Terminated) do
    Application.ProcessMessages;

 End;

Begin

 aQuery.DisableControls;

 Proc_ShowProgressTabela;

 aQuery.EnableControls;

End;

procedure TForm1.Button3Click(Sender: TObject);
begin
 Button3.Enabled := False;

 Func_OpenCDS(IBCQuery1, 'Query A');

 Button3.Enabled := True;

end;

ViktorV
Devart Team
Posts: 2632
Joined: Wed 30 Jul 2014 07:16

Re: Error Creating a "TIBCConnection" inside a Thread.

Post by ViktorV » Wed 08 May 2019 12:30

Unfortunately, we could not reproduce the issue.
To understand the issue cause, we need a test sample or a configured environment in which the issue is stably reproduced. As soon as we get this sample or can reproduce the error and, if the cause of the issue is in the code of our product, we will try fixing it as soon as possible.
Therefore, please compose and send us using contact form https://devart.com/company/contactform.html a full sample including Firebird DB file. Also, please specify the Firebird and IDE versions you are using.

luapfr
Posts: 28
Joined: Thu 11 Apr 2013 13:11

Re: Error Creating a "TIBCConnection" inside a Thread.

Post by luapfr » Wed 08 May 2019 14:41

what is the problem this error is random is not happening directly, happened on two clients, however in my computer does not happen.

Looking at the code I gave you can you see any errors ?

ViktorV
Devart Team
Posts: 2632
Joined: Wed 30 Jul 2014 07:16

Re: Error Creating a "TIBCConnection" inside a Thread.

Post by ViktorV » Fri 10 May 2019 08:29

Unfortunately, we couldn’t reproduce the issue using your data. The issue is not caused by our components; it is returned by the Firebird server and may stem from a large number of simultaneous connections with the server.

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