[Qgis-developer] Oracle layers - improving the speed

Jürgen E. Fischer jef at norbit.de
Mon Feb 10 07:41:21 PST 2014

Hi Jonathan,

On Mon, 10. Feb 2014 at 13:43:44 +0000, Jonathan Moules wrote:
> Thinking about it, the simplest solution is to just trust
> MDSYS.USER_SDO_GEOM_METADATA and get everything from that where possible -
> SRID and BBOX. The geometry-type it doesn't have, but is that strictly
> necessary for the list?

There's always an extent, but that not necessarily reflect an actual bbox, but
just sets the available bounds, which are often set much bigger than the actual
data.  But the bounding box is determined after insertion of the layer anyway.
To insert the layer we just need tablename, column, type and srid - and that's
what the thread searches for.

An additional idea would be to use the filters upfront.  Currently you can only
filter the result of the layer search after the search has already been run.
Instead we could reduce the searches we want by just looking for tables with
given (partial) name, in a given schema, srid and/or geometry type.  Especially
in cases where the search is expensive, because there are loads of tables, this
is would even be useful if performance wasn't an issue.

And that would also be interesting for all other database providers.


Jürgen E. Fischer         norBIT GmbH               Tel. +49-4931-918175-31
Dipl.-Inf. (FH)           Rheinstraße 13            Fax. +49-4931-918175-50
Software Engineer         D-26506 Norden               http://www.norbit.de
QGIS PSC member (RM)      Germany                      IRC: jef on FreeNode                         

norBIT Gesellschaft fuer Unternehmensberatung und Informationssysteme mbH
Rheinstrasse 13, 26506 Norden
GF: Jelto Buurman, HR: Amtsgericht Emden, HRB 5502

More information about the Qgis-developer mailing list