[Gdal-dev] Gdalwarp and memory optimization

[Nicolas Ribot]

> Nicolas,
>
> I would also note that setting the GDAL_CACHEMAX parameter higher
> can be helpful.  The -wm flag sets the amount of memory used for the
> big working buffers (the chunks) when warping.  But down within GDAL
> itself the format drivers use a block cache which comes from a seperate
> memory pool controlled by GDAL_CACHEMAX.   So on a 1GB system you might
> do something like:
>
>    gdalwarp -wm 400 --config GDAL_CACHEMAX 150 ...
>
> This would allocate up to 550MB of RAM between the warping chunk arrays
> and the generic cache.  In fact, GDAL_CACHEMAX can also be set as an
> environment variable.  And I'd encourage folks with lots of RAM to set
> this in their environment normally.   The default small cachesize can
> kill performance in some fairly common situations with large files
> (such as gdal_translate conversions between line oriented and tiled files).
>

Hi Franck and thank you very much for these details.

I will try this parameter and must precise that increasing cache size
with the -wm switch reduced a lot the processing time for my dataset

Best regards

nicolas