Problem with localfilover and TmyQuery.Execute.

[eduardosic]

Hi, i found a small problem.

the TmyQuery.Execute don't reconect on server with localfailover = true and OnLostConnection > RetryMode := TRetryMode( 2 )

with the TMyQuery.Open, all rigth.

the sample demonstrate it.

http://www.drdsistemas.com/util/failover.zip

[Antaeus]

I do not have enough privileges to download this archive. Please send it to me at evgeniyd * crlab * com.
Exclude exe file(s) from the archive if it is included.

[eduardosic]

I do not have enough privileges to download this archive. Please send it to me at evgeniyd * crlab * com.
Exclude exe file(s) from the archive if it is included.

I finished to send.

Thank's.

[eduardosic]

I do not have enough privileges to download this archive. Please send it to me at evgeniyd * crlab * com.
Exclude exe file(s) from the archive if it is included.

I finished to send.

Thank's.

Antaeus you it received the email with the example?

[Jackson]

Currently MyDAC doesn't support reexecuting queries after the connection is lost.
We will add this functionality in the next build of MyDAC 5.

[eduardosic]

Currently MyDAC doesn't support reexecuting queries after the connection is lost.
We will add this functionality in the next build of MyDAC 5.

Using TMyQuery.Open; the reconnection and reexecution are OK.

Using TMyQuery.Execute; the exception lost connection is raised.

TMyConnection works with
- DisconnectModel
- Pool of conections
- LocalFailOver
and OnLostConnection = ReconnectAndExecute.

thank's

[eduardosic]

Hi DevArt.

LocailFailOver don't work with a Update or Insert Statment. with Select works fine.. please, fix it. localfailover is a big feature.

[Dimon]

To solve the problem you should process the OnConnectionLost event of TMyConnection and set the RetryMode value to rmReconnectExecute, like this:

Code: Select all

procedure TForm1.MyConnectionConnectionLost(Sender: TObject;
  Component: TComponent; ConnLostCause: TConnLostCause; var RetryMode: TRetryMode);
begin
  if ConnLostCause = clExecute then
    RetryMode := rmReconnectExecute;
end;

[eduardosic]

To solve the problem you should process the OnConnectionLost event of TMyConnection and set the RetryMode value to rmReconnectExecute, like this:

Code: Select all

procedure TForm1.MyConnectionConnectionLost(Sender: TObject;
  Component: TComponent; ConnLostCause: TConnLostCause; var RetryMode: TRetryMode);
begin
  if ConnLostCause = clExecute then
    RetryMode := rmReconnectExecute;
end;

i use

procedure TForm1.MyConnectionConnectionLost(Sender: TObject;
Component: TComponent; ConnLostCause: TConnLostCause; var RetryMode: TRetryMode);
begin
RetryMode := rmReconnectExecute;
end;

But a found the problem. if a have a opened query (select * from) with a property FetchAll = False and try do execute a update and the connection is lost.. a exception is raised and the OnConnectionsLost event is'nt called.

uuf, 1hour to find the problem.

[Dimon]

MyDAC help says:

If a connection breaks, a fatal error occurs, and the OnConnectionLost event will be raised if the following conditions are fulfilled:

• There are no active transactions;
• There are no opened and not fetched datasets;
• There are no explicitly prepared datasets or SQLs.

[eduardosic]

MyDAC help says:

If a connection breaks, a fatal error occurs, and the OnConnectionLost event will be raised if the following conditions are fulfilled:

• There are no active transactions;
• There are no opened and not fetched datasets;
• There are no explicitly prepared datasets or SQLs.

FailOver under a Active Transaction is a Best Feature for MyDAC 6.

about fetchAll, i remove all fetchall = false in my app

[Dimon]

Thank you for your inquiry. We will investigate the possibility of adding this functionality in the future.