On a very slow query, how do I indicate percentage of progress

Question

I'm using ZEOS components to connect to an (ancient) MDB database.
I'm doing a query that reads in lots of data to bridge into a different database.

Is there a way to indicate progress as a percentage?

procedure TForm13.ActionReadInMemoryExecute(Sender: TObject);
var
  QueryLine: string;
  FullQuery: string;
  Tablename: string;
  i: integer;
begin
  i:= 0;
  TableMeter.DisableControls;
  try
    TableMeter.First;
    FullQuery:= '';
    while not TableMeter.eof do begin
      Tablename:= TableMeter.FieldByName('tabelnaam').AsString;
      QueryLine:= ReplaceStr(ImportQuerySjabloon, cTabelname, Tablename);
      FullQuery:= FullQuery + QueryLine;
      if (TableMeter.RecNo < (TableMeter.RecordCount -1)) then begin
        FullQuery:= FullQuery + ' UNION ALL ';
      end;
      TableMeter.Next;
    end; {while}
    QueryImportMeterreadings.Close;
    QueryImportMeterreadings.SQL.Text:= FullQuery;
    QueryImportMeterreadings.Open;  <<-- takes a long time
  finally
    TableMeter.EnableControls;
  end;
end;

Is there a way to indicate progress of the query, or can I only do this if I split up the individual queries and eliminate the UNION's.
It takes about 1 minute to run, involving 8 unions.

I don't see any event that I can use for this purpose:

Or should I fake an OnCalcField on a field in the Query to do this (not sure if that will even work in principle).
Or attach a sequence? nope, gives unsupported operation on a Access DB

Answer 1

I say split up the individual queries and eliminate the union, make a timer around each query, depending on the avg time taken * number of queries remaining you should give an estimate / update a text field to say x out of y queries completed (time remaining: -time-)