[Qgis-developer] Problem with the MySQL/GDAL implementation in QGIS

[Pavol Hnila]

Thank you very much, Jürgen.

> From my experience MySQL is rarely used for GIS - so the demand for
> a mysql provider is very low.
I see. Demand is evidently not high, but MySQL is improving steadily,
so it would be great to keep OGR functional in QGIS.

> That's odd.  QGIS just opens the OGR data source and the requested
> layer.  Does 536135a help?  It limits the data source opened for
> each layer to the table it's going to request.
Yes, 536135a works. It eliminates all the queries that were not
related to the requested layer. This means a huge improvement for the
performance in cases where the database contains more tables.

The principal problem pointed out by Even however remains - the
repeated opening and closing of the OGR datasource for every record in
the table. I will try to figure out which nightly build between 1.8
and 2.0 release caused this change in behaviour. Since I cannot figure
it out in the code and need to try manually, this can take some time.
Unless someone else on the list can figure it out from the master code ...

Pavol