[postgis-devel] Final section, raster architecture document

[Chris Hodgson]

Bryce L Nordgren wrote:
> The drawback, of course, is that it loads both input rasters and the 
> output raster completely into memory at the same time (assuming they 
> are all in-database rasters).
>
Maybe I'm taking this out of context, but this seems like a pretty 
serious drawback, with the expectation being that any raster big enough 
to be worth putting in the database is quite likely to be larger than 
can fit in memory (or in 1/3 of memory even, given similarly sized 
inputs and output). Or are the rasters that we are talking about being 
loaded, just the smaller "chunks"? Regardless I don't think it can be 
assumed that any arbitrary raster we wish to operate on will necessarily 
be chunked/gridded into an appropriate size, and it seems to me that a 
"Grid iteration engine" for the purposes of pgraster, would need to able 
to read chunks of input and write chunks of output, of a reasonable size.

Again, sorry if I've misunderstood you.

Chris