Efficiently retrieve MANY records with Advanced Datagrid?

Question

Hi all,
I've encountered the following issue:
I have a database with more then 120.000 records, that I want to show with an advanced datagrid.
It's grouped by 2 ID's, thus showing the results a group within a group. This works perfect!
Only: it takes a long time before it shows the results, probably because it's downloading all the records at once (with the getAll() function).
Is there a way to use advanced datagrid more efficiently? Like: first download the two columns that are used to define the groups, and only retrieve data that's visible once you click the group? (In this case, the 2nd group within the 1st group)
This would greatly increase the loading-time of the whole application.
Or should I take an other aproach to this application, like, using a tree-component, a simple datagrid, writing alternative update & retrieve functions in AS3 & PHP?
Thanks!

Answer 1

Hi Sam, thanks for your help!
I'm not sure though how to create the returned datastructure?
Example:
Product_id
productname
category_a
category_b
1
Toy A
boy
0-3
2
Toy B
girl
0-3
3
Toy C
girl
3-6
4
Toy D
boy
6-9
5
Toy E
girl
3-6
6
Toy F
boy
0-2
7
Toy G
boy
6-9
Grouping by [category_a] and [category_b], I would like to get the following in the Advanced Datagrid, but paginated:
Product_ID
Productname
boy
0-2
6
Toy F
0-3
1
Toy A
6-9
4
Toy D
7
Toy G
girl
0-3
2
Toy B
3-6
3
Toy C
5
Toy E
In my PHP-service, I would create the following query:
     public function getProducts_paged($startIndex, $numItems) {
          $stmt = mysqli_prepare($this->connection, "SELECT product_id, category_a, category_b, productname FROM $this->tablename GROUP BY category_a, category_b LIMIT(?,?)");
          $this->throwExceptionOnError();
          mysqli_bind_param($stmt, 'ii', $startIndex, $numItems);
          mysqli_stmt_execute($stmt);
          $this->throwExceptionOnError();
          $rows = array();
          mysqli_stmt_bind_result($stmt, $row->product_id, $row->category_a, $row->category_a, $row->productname);
         while (mysqli_stmt_fetch($stmt)) {
           $rows[] = $row;
           $row = new stdClass();
           mysqli_stmt_bind_result($stmt, $row->product_id, $row->category_a, $row->category_a, $row->productname);
          mysqli_stmt_free_result($stmt);         
          mysqli_close($this->connection);
          return $rows;
This will give me the right structure, Right?
Now:
- How to tell the Advanced Datagrid which 2 groups to apply?