[fdo-internals] Question about FDOOGRProvider

Gabriele Monfardini gabrimonfa at gmail.com
Thu Mar 27 02:17:21 PDT 2014

Hi Greg,

thank you for your quick response.

> I suppose one could call that function using FALSE, and only use TRUE on
> error
> OGRErr err =
> m_connection->GetOGRDataSource()->GetLayer(m_nIndex)->GetExtent(&e, FALSE);
> If (err)
>     err =
> m_connection->GetOGRDataSource()->GetLayer(m_nIndex)->GetExtent(&e, TRUE);
I've made some tests.
Simply calling the function with FALSE does not yield any benefit since OGR
performs the same queries.
Moreover I'm a bit concerned that no check is performed to detect an OGR
failure, which seems to be more likely since it leaves the OGR driver the
option to return a failure if evaluating the extent is too expensive.

I've also made a more radical change, commenting out the call to libgdal
and returning an hard coded extent.
Apparently all works correctly inside MapGuide (and first map loading is
very quick now), so probably the extent is not used a lot (or at least is
not used in my particular workflow).

This obviously has nothing to do with FDO and should be investigated on
MapGuide side, so I will try to post my findings also in MapGuide Internals
mailing list.


Gabriele Monfardini
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/fdo-internals/attachments/20140327/d9afd5ea/attachment.html>

More information about the fdo-internals mailing list