try
    FDQuery.ExecSQL; //если не вовремя, то возвращается ошибка
    FDQuery.Close;
except
   on E: EFDDBEngineException do begin
    if E.Kind = ekServerGone then
    EConnect:= True
    else  EOracle:= True;
    end;
    on E: EFDException do begin
     EFD:= True;
     end;
     on E: exception do begin
     EOther:= True;
     end;
end;

function CheckConnection: boolean;
var
  Q: TFDQuery;
begin
  Result:= False;
  
  try
    if FDConnection.Connected then
    begin
      Q:= TFDQuery.Create(nil);
      Q.Connection:= FDConnection;
      try
        Q.SQL.Text := 'select 1 from dual';
        Q.Execute;
        Result:= True;
      except
        on E: exception do
        begin
          Result:= False;
          try
            FDConnection.Open;
            Result:= True;
          except
          end;
        end;
      end;
      Q.Free;
    end
    else
    begin
      FDConnection.Open;
      if FDConnection.Connected then
      Result:= True
      else Result:= False;
    end;
  except
    on E: exception do
    begin
      WriteErrorLog(e.Message);
    end;
  end;
end;

procedure CreateConnectionDef(const AName, AUser, APassword, AConnectStr: string; const APool: boolean; const ACountMax: integer);
var
  ConnectionDef: IFDStanConnectionDef;
begin

  ConnectionDef:=FDManager.ConnectionDefs.AddConnectionDef;
  ConnectionDef.Params.Clear;
  ConnectionDef.Name:= AName;
  ConnectionDef.Params.UserName:= AUser;
  ConnectionDef.Params.Password:= APassword;
  ConnectionDef.Params.Database:= AConnectStr;
  ConnectionDef.Params.DriverID:= 'Ora';

  if APool then begin
    FDManager.ConnectionDefs.ConnectionDefByName(AName).Params.Pooled := True;
    FDManager.ConnectionDefs.ConnectionDefByName(AName).Params.PoolMaximumItems := ACountMax;
  end;
end;

FDPhysOracleDriverLink1.NLSLang:= 'AMERICAN_AMERICA.CL8MSWIN1251';
FDPhysOracleDriverLink1.VendorLib:= '/opt/oracle/instantclient_12_2/libclntsh.so';
FDManager.Close;
while FDManager.State <> dmsInactive do
Sleep(0);
FDManager.Open;
CreateConnectionDef(DefaultConDefNamePool, user_name, passwd, con_str, True, MAX_SESSION_COUNT);

oConnection := TFDConnection.Create(nil);
oConnection.LoginPrompt:= False;
oConnection.ResourceOptions.SilentMode:= true;
oConnection.ResourceOptions.AutoReconnect:= true;

function TDBPacket.Connect2Server(AConnection: TFDConnection): boolean;
begin
  try
  AConnection.ConnectionDefName:= DefaultConDefNamePool;
  AConnection.Connected:= True; //ушел в себя приду не скоро
  except
     логирование - но нет записи
  end;
end;

AutoConnect:= False;
AutoReconnect:= False;