Lost connection to MySQL Server during query
Posted: Fri 04 Jul 2014 15:43
Hello,
I am getting an error message/exception when trying to execute a query to a remote mySQL DB.
I am using Delphi XE6, FM Mobile app (iOS),Unidac 5.3.9
The raised exception is: Lost connection to MySQL Server during query
I have searched your forum for this error and found a few suggestions, but I still cannot get it to work. The exception is raised about 1-3 seconds after I execute the query. The variable setting on my server show I will not get a timeout until after 10 seconds.
Here's the code. I hope it is something simple to fix. This problem does not occur every time, but about 75% of the time. So I know the code works occasionally.
One of the suggestions on the forum was to put RetryMode := rmReconnectExecute in the OnConnectionLost event.
Regards,
Bryan
I am getting an error message/exception when trying to execute a query to a remote mySQL DB.
I am using Delphi XE6, FM Mobile app (iOS),Unidac 5.3.9
The raised exception is: Lost connection to MySQL Server during query
I have searched your forum for this error and found a few suggestions, but I still cannot get it to work. The exception is raised about 1-3 seconds after I execute the query. The variable setting on my server show I will not get a timeout until after 10 seconds.
Here's the code. I hope it is something simple to fix. This problem does not occur every time, but about 75% of the time. So I know the code works occasionally.
One of the suggestions on the forum was to put RetryMode := rmReconnectExecute in the OnConnectionLost event.
Regards,
Bryan
Code: Select all
Procedure TfrmPlotHModel.ConnectToDB;
Begin
if not UniConnection1.Connected then
Try
UniConnection1.Connect;
Except
begin
ShowMessage('Cannot Connect to the Database');
Exit;
end;
End;
End;
procedure TfrmPlotHModel.tableViewHModelByModelRunItemSelect(Sender: TObject;
ASection, ARow: Integer);
var
selectedItem : TTMSFMXNativeUITableViewItem;
adate : TDateTime;
Points : TList<TTMSFMXNativeMKMapLocation>;
Locations : TArray<TTMSFMXNativeMKMapLocation>;
Point : TTMSFMXNativeMKMapLocation;
Poly : TTMSFMXNativeMKOverlay;
x, x1 : integer;
s1, PrevModel : String;
begin
ConnectToDB;
ProgressModelPlot.Progress := 0;
PrevModel := '';
SelectedItem := tableViewHmodelByModelRun.GetItem(aSection,aRow, false);
aDate := StrToDateTime(SelectedItem.Text);
aQuery.SQL.Clear; //TUniQuery
aQuery.Close;
aQuery.SQL.Add('SELECT * FROM stormdata WHERE storm_id = '+quotedStr(SelectedStormID)+
' AND date = '+quotedStr(SQLDateTime(aDate)));
aQuery.SQL.Add('ORDER BY tech, date_fore');
s1 := aQuery.SQL.Text;
aQuery.Prepare;
aQuery.Open;
x1 := 0;
if not aQuery.IsEmpty then
begin
Points := TList<TTMSFMXNativeMKMapLocation>.Create;
Try
frmMain.Map.BeginUpdate;
while not aQuery.Eof do
begin
ProgressModelPlot.Progress := (x1+1 / aQuery.RecordCount);
Application.ProcessMessages;
if (PrevModel <> '') and (aQuery.Fields[3].AsString <> PrevModel)
and (Points.Count > 1) then
begin
//this is a new model, so plot the last one.
PlotSingleModel(Points,GetRandomColor,3);
Points.Clear;
end;
Point.Latitude := ConvertCoordinate(aQuery.Fields[5].AsString);
Point.Longitude := ConvertCoordinate(aQuery.Fields[6].AsString);
if Point.Latitude <> 0 then
Points.Add(Point);
PrevModel := aQuery.Fields[3].AsString;
aQuery.Next;
Inc(x1);
end;
//Plot the last set
if Points.Count > 1 then
PlotSingleModel(Points,GetRandomColor,3);
frmMain.Map.EndUpdate;
Finally
Points.Free;
End;
end;
ProgressModelPlot.Visible := False;
end;