[postgis-devel] [raster] About recent commit r8313

[Chris Hodgson]

I listened with some surprise to the earlier discussions about removing 
regular blocking, but remained silent as I didn't have the time to 
really think about it. But I'd like to lend my support to Mateusz's 
complaint... is it truly wise to throw away the opportunity to optimize 
this case? In my work with rasters, all of the other "random bunch of 
rasters" use cases are just a stepping stone on the way to "the one" 
complete, regularly blocked/tiled dataset. The regularly blocked raster 
is the one that needs to be fastest, as it is the one that end users 
would be most likely to render maps from. Plus, it is the one with the 
most potential for optimization. Frank's a pretty smart guy, he's been 
doing rasters since before PostGIS was a gleam in our collective eye, I 
wouldn't bet against him on this.

Chris

On 11-12-07 09:49 AM, Mateusz Łoskot wrote:
> Folks,
>
> If I may, I'd like to gently complain about the recent change in the
> raster part:
>
> http://trac.osgeo.org/postgis/changeset/8313
>
> Do we really want this change?
> In my opinion, it is not a good idea for the best performance possible.
>
> The natural block concept is there for purpose and operating on larger strips
> performs better.
>
> I had a quick talk with Frank and, I hope Frank does not mind me quoting him,
> there is another issue:
>
> "It was my understanding/hope that postgis raster would be highly optimized
> for the postgis regular blocking case and I had hoped that in at least
> some cases that
> would be setup to map 1:1 to regular blocking in source or destination
> GDAL files.
> This certainly discards any hope of such optimization in this api."
>
> Best regards,