[postgis-devel] [raster] Memory management and IO concerns

[Mark Cave-Ayland]

On 24/06/11 00:04, Bryce L Nordgren wrote:

> Is there a way to encapsulate "DETOAST" logic such that only the raster
> header, a specific band header, and the corresponding band data are
> loaded? I'd hate to have to write that logic in more than one function.
> And the correlary, can you DETOAST different slices as they're needed or
> do you have to load everything upfront? (e.g., load image blocks?)

Unfortunately I don't think so; I think you'd have to disable TOAST on 
the raster column and then implement some kind of custom grid 
compression scheme to avoid having to decompress an entire raster as 
part of the PG_DETOAST_DATUM() call. But someone else who knows better 
may be able to correct me here.


HTH,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
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