SQL Server Delphi Tokyo更新1下的性能缓慢firedac

Question

Using a simple query that returns 20.000 rows only takes 0.5 milliseconds with ADO, but using firedac it takes 30 seconds.

This is the code used for FireDac and ADO test:

procedure TForm18.Button1Click(Sender: TObject);
var
  i: DWORD;
begin
  i := GetTickCount;

  Query.DisableControls;
  Query.Active := false; // simple SQL SELECT * FROM TABLE
  Query.Active := true;
  Query.EnableControls;
  Caption :=  IntToStr(GetTickCount - i) + ' - ' + IntToStr(Query.RecordCount);
end;

Regards

Answer 1

Please try setting the ExtendedMetadata to False for better performance. Try using also the RecordCount property with the number of records expected and you may see better results.

That SELECT statement does not use any indexes so a full scan of the database is occurring. Try to compare performance with a query that filter results and make use of indexes use indexes instead.

You can alos use ADMonitor to see how the application interacts with the database as explained here .

Finally, I have read about slow performance when FireDac uses ODBC and also when FireDac reads BLOB data.

Hope this helps.