Re: [OSGeo-Discuss] Raster data on RDBMS

[Lucena, Ivan]

Frank,

>  My point is that a tile caching approach is really comparing tile caching
>  performance to rendering-on-demand performance while I think the original
>  point was that rendering-from-database and rendering-from-filesystem could
>  have similar performance for input raster data.

D'accord.

>  Your comparison is also of interest but I don't think it is fair to compare
>  rendering from Oracle through MapServer (or GeoServer) to satisfying
>  map requests directly from a tile cache.

I shouldn't have mentioned MapServer. Web-serving wasn't my point to beginning with. I can gdal_translate from 
the georaster driver to vrt and open the result on OpenEV. That gives me a good idea of how the driver perform in 
a rendering environment. I would need to change OpenEV do it directly. But by doing that I would be testing GDAL 
not Oracle. To see Oracle Georaster in action I can use some freeviewer (free as in gratis). That is not my point.

The real point is should we discard RDBMS for Raster storage just because we are sure that there will be overhead, 
ours direct fopen(), fread() will always be faster? Myth or fact? Those tests have proven otherwise so the question 
is what is going own?

I messed around with some free-open-source RDBMS a long time ago (last century actually), checking out how to 
create type extension. But I would not imagine getting into to the core of how does things work just for the fun of 
it. So, the only thing I can do is to check the results from the outside and Oracle+GDAL/GeoRaster is the 
environment that let me do that because they let you use the software without a license, as long it is not on 
production mode. 

I should test mySQL+TerraLib or PostGIS+GDAL/PGCHIP also. Maybe.

Best regards,

Ivan