[Mapserver-users] Mapserver - OGR - Oracle (revisited)

[Frank Warmerdam]

bartvde at xs4all.nl wrote:
> Hi list,
> 
> on a previous post I mentioned that it appeared that the BBOX of the WMS
> request was not used in the query sent to Oracle.
> 
> This was caused by the DATA statement in the MAP file. If we used a select
> statement there (like the one commented out in the example below), always
> a full table scan was performed. Using the lower "syntax" it works fine.
> 
> #   DATA "select ORA_GEOMETRY from AdreSDO"
>     DATA AdreSDO
> 
> But now there is the following problem that a WMS GetCapabilities request
> takes more than one minute (also resulting in a full table scan in
> Oracle). Is there any way to prevent this, can it be read from the
> USER_SDO_GEOM_METADATA table or the MAP file?

Bart,

As I think Daniel noted in another message, you can pre-supply the extent
(which is what I assume is taking a long time).  The better solution would
be for me to override the OGR OCI driver's GetExtent() logic to use the
USER_SDO_GEOM_METADATA as you suggest.  I kind of thought I had done that,
but looking through the code I see the generic logic is used which involves
reading the complete table.

Feel free to submit that as an enhancement request in the GDAL/OGR
bugzilla.

While a great deal of work went into optimization of the OCI driver for
loading Oracle with data, the read side was not nearly as well optimized
since that was not the focus of the funding project.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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