The data is chunked in Oracle into tiles, so unless you tile the TIFF as well you aren't really doing a direct comparison. Even if you end up with the same numbers for both processes, I'll still be impressed, since I assumed Oracle would have a higher overhead.
P. On Tue, Oct 28, 2008 at 9:54 PM, Lucena, Ivan <[EMAIL PROTECTED]> wrote: > Hi There, > > I would like to return to a discussion that we had months ago about raster on > RDBMS. But this time I would like to present some number. > > As long as I could recall there was basically two major arguments contrary to > storing raster on RDBMS. One very pragmatical: "Why waste precious process > time with the overhead of dealing with queries, tables, client-sever back and > forth just to get the data from BLOB fields on a database when you can get it > directly from the file system?". The other argument was semantical: "Why > store raster on RDBMS if in general we are not expecting to have a > transactions on that data?" > > I cannot argue against the second one. I basically agreed with that but after > seeing how fragile and complicated even a well defined structure of folders > and files could be I would vote in favor of the good and old relational model. > > That is my experiment. I downloaded two free data samples from Naveteq > website. Two geotiff files with the same size and number of bands (14336, > 14336, 3): > > [EMAIL PROTECTED]:~/Data> du -k Barcelona_2007_R2C2.TIF > 602828 Barcelona_2007_R2C2.TIF > [EMAIL PROTECTED]:~/Data> du -k San_Francisco_2006_R1C2.TIF > 602828 San_Francisco_2006_R1C2.TIF > > Then I loaded those images to Oracle Spatial GeoRaster using GDAL. The > loading process is comparable than some commercial ETL products on the > market. It took about 2 minutes to load each image. > > [EMAIL PROTECTED]:~/Data> time gdal_translate -of georaster > Barcelona_2007_R2C2.TIF georaster:scott,tiger,orcl,RDT_2$,2 > Input file size is 14336, 14336 > 0...10...20...30...40...50...60...70...80...90...100 - done. > Ouput dataset: (georaster:scott,tiger,orcl,RDT_2$,2) on GDAL_IMPORT,RASTER > real 1m54.973s > user 0m4.368s > sys 0m1.936s > > If you are a Oracle GeoRaster users you might be excited about those number > already but those are not the numbers I want to show. What I would like to do > is to compare the time that it takes to extract subset from the original > geotiff and compare with the time to extract the same subset from the RDBMS. > He are the numbers: > > [EMAIL PROTECTED]:~/Data> time gdal_translate > georaster:scott,tiger,orcl,RDT_2$,2 out.tif -srcwin 0 0 2000 2000 > Input file size is 14336, 14336 > 0...10...20...30...40...50...60...70...80...90...100 - done. > real 0m0.720s > user 0m0.408s > sys 0m0.108s > > [EMAIL PROTECTED]:~/Data> time gdal_translate Barcelona_2007_R2C2.TIF > out2.tif -srcwin 0 0 2000 2000 > Input file size is 14336, 14336 > 0...10...20...30...40...50...60...70...80...90...100 - done. > real 0m1.177s > user 0m0.976s > sys 0m0.188s > > And I also checked the integrity of the results to see if I get the same > result: > > [EMAIL PROTECTED]:~/Data> gdalinfo -checksum out.tif > ... > Band 1 Block=2000x1 Type=Byte, ColorInterp=Red > Checksum=58248 > Band 2 Block=2000x1 Type=Byte, ColorInterp=Green > Checksum=21226 > Band 3 Block=2000x1 Type=Byte, ColorInterp=Blue > Checksum=8002 > > [EMAIL PROTECTED]:~/Data> gdalinfo -checksum out2.tif > ... > Band 1 Block=2000x1 Type=Byte, ColorInterp=Red > Checksum=58248 > Band 2 Block=2000x1 Type=Byte, ColorInterp=Green > Checksum=21226 > Band 3 Block=2000x1 Type=Byte, ColorInterp=Blue > Checksum=8002 > > What are others test would be interesting to perform? > > Best regards, > > Ivan > > > > > > > > > > > > > _______________________________________________ > Discuss mailing list > Discuss@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/discuss > _______________________________________________ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
