Bug with multiple connections

Bug with multiple connections

Postby gbpenha » Mon 25 Feb 2008 18:29

Hi,

When I use multiple connections and try to use then simultaneously, the component seems to lost the connection with one of the connections, when a table on it have a lot of lines (here, the error occurs with more than 1223 lines).

Follow a example of code, (Delphi 2007 IDE, but should work in another version as well):

Code: Select all
program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  Messages,
  Variants,
  Classes,
  WideStrings,
  DB,
  SqlExpr,
  DBXCommon;

var
  SQLQuery, SQLQuery2: TSQLQuery;
  SQL: String;
  Sql1: string;
  StartDate, EndDate: string;
  cont: integer;

function ConnectToDatabase: TSQLConnection;
begin
  try
    Result := TSQLConnection.Create(nil);
    // Change the path of the database here - we´re using Firebird 1.5
    Result.Params.Text := 'DriverName=InterBase by Core Lab' + #$D#$A
      + 'Database=127.0.0.1:C:\DB_TEST.GDB' + #$D#$A
      + 'User_Name=sysdba'+ #$D#$A
      + 'Password=masterkey' + #$D#$A
      + 'SQLDialect=3' + #$D#$A
      + 'BlobSize=-1' + #$D#$A
      + 'InterBase by Core Lab TransIsolation=ReadCommited' + #$D#$A
      + 'WaitOnLocks=True' + #$D#$A
      + 'CharLength=1' +#$D#$A
      + 'EnableBCD=True' + #$D#$A
      + 'OptimizedNumerics=False'+#$D#$A
      + 'LongStrings=True'+#$D#$A
      + 'UseQuoteChar=False'+#$D#$A
      + 'FetchAll=False'+#$D#$A
      + 'UseUnicode=False'+#$D#$A;
   
    Result.ConnectionName := 'InterBase by Core Lab';
    Result.DriverName := 'InterBase by Core Lab';
    Result.GetDriverFunc := 'getSQLDriverInterBase';
    Result.LibraryName := 'dbexpida40.dll';
    Result.VendorLib := 'fbclient.dll';
    Result.Connected := true;
  except
  on E: Exception do
  begin
    Result := nil;
    WriteLn(E.Message);
  end;
  end;
end;

begin

  try
      cont := 0;

      SqlQuery := TSQLQuery.Create(nil);
      SQLQuery.SQLConnection := ConnectToDatabase;
      SQLQuery.SQL.Text := 'SELECT * from posicao;';
      Writeln('Executing query...');
      SQLQuery.ExecSQL;
      writeln('Query ok...');
      SQLQuery.Open;
      SQLQuery.First;

      while not SqlQuery.Eof do
      begin
        SqlQuery.Next;

        // When the number of lines reaches 1223, the problem will occur
        if ((cont mod 100) = 0) or (cont > 1220) then
          // So we show the line number
          writeln(cont);

        Inc(cont);

        SqlQuery2 := TSQLQuery.Create(nil);

        // If I use the same connection created previously, the error doesn´t occur
        // Like: SqlQuery2.SQLConnection := SqlQuery.SQLConnection;

        // But creating a new connection it occurs whith any query here, inside the while
        SqlQuery2.SQLConnection := ConnectToDatabase;
        SqlQuery2.SQL.Text := 'select 1 from rdb$database;';
        SqlQuery2.ExecSQL;
        SqlQuery2.Open;
        SqlQuery2.First;
        FreeAndNil(SqlQuery2);
      end;

      except
      on E: Exception do
        WriteLn('Error : ' + E.Message );
      end;
  Writeln('END - TESTS OK!');
end.


The table schema is:

Code: Select all
/******************************************************************************/
/***          Generated by IBExpert 2006.03.07 25/2/2008 15:23:46           ***/
/******************************************************************************/

SET SQL DIALECT 3;

SET NAMES NONE;

CREATE DATABASE 'C:\ProjetoConsole\DB_TEST.gdb'
USER 'SYSDBA' PASSWORD 'masterkey'
PAGE_SIZE 16384
DEFAULT CHARACTER SET NONE;



/******************************************************************************/
/***                                 Tables                                 ***/
/******************************************************************************/



CREATE TABLE POSICAO (
    COMUNICACAO_ID  INTEGER NOT NULL,
    LONGITUDE       DOUBLE PRECISION,
    LATITUDE        DOUBLE PRECISION,
    LOCALIZACAO     VARCHAR(50),
    DIRECAO         SMALLINT,
    DIRECAOSTR      VARCHAR(2),
    LOGRADOURO      VARCHAR(100),
    VALIDA          SMALLINT NOT NULL,
    VELOCIDADE      INTEGER,
    TIPO            INTEGER DEFAULT 0 NOT NULL,
    IGNICAO         INTEGER default 2
);


The rows looks like this, but I have 1330 of them on the table.

Code: Select all
INSERT INTO POSICAO (COMUNICACAO_ID, LONGITUDE, LATITUDE, LOCALIZACAO, DIRECAO, DIRECAOSTR, LOGRADOURO, VALIDA, VELOCIDADE, TIPO, IGNICAO) VALUES (110481978, -51.886745, -23.431934, 'Maringa - PR', 0, 'N', 'Br 376, 1, 0, 0, 1);


Any suggestion?
gbpenha
 
Posts: 1
Joined: Wed 26 Sep 2007 14:22

Postby Plash » Tue 26 Feb 2008 08:43

We could not reproduce the problem. Please send to dbxida*crlab*com a complete sample that demonstrates the problem, including the test database. Also specify whether you using Classic or Super Server Firebird server.
Plash
Devart Team
 
Posts: 2844
Joined: Wed 10 May 2006 07:09


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