[gdal-dev] multiple access to a file

[Etienne Tourigny]

On Tue, May 21, 2013 at 7:30 AM, Jose Gomez-Dans <jgomezdans at gmail.com>wrote:

> Hi Frank,
>
>
>
> On 21 May 2013 00:02, Frank Warmerdam <warmerdam at pobox.com> wrote:
>
>> If you write a small part of an image, GDAL is likely to read a larger
>> area, update that and write it back.  If other programs happen to try and
>> update the same larger area at the same time some data is likely to be
>> lost.
>>
>
> Thanks for your reply. However, locking the output files would still work?
> Provided the cache has been flushed between the open/close dataset calls,
> it should be fine?
>

I guess it would work, but you probably won't get much speedup this way.

Like Frank says, not sure it would be so trivial as you would have to
implement something like MPI in the gdal I/O routines and take care that
blocks are assigned to each MPI process.

If you have many files to process, it might be easier to distribute the
many files over many machines simultaneously,  but write one file per
machine only.

cheers
Etienne


>
> Thanks!
> Jose
>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20130521/d8f865f2/attachment.html>