[gdal-dev] Re: GDAL 1.5.0 is slow

Ed McNierney ed at topozone.com
Wed Mar 5 15:08:49 EST 2008


Mike -

What is the filesystem on the volume holding the NITF files, and is it a local or network drive?  If network, what network protocol is used?

I had a theory about the cause of this symptom earlier, and your info would help be either confirm or discredit that theory - thanks.

	- Ed

Ed McNierney
Chief Mapmaker
Demand Media / TopoZone.com
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: 978-251-4242, Fax: 978-251-1396
ed at topozone.com

-----Original Message-----
From: gdal-dev-bounces at lists.osgeo.org [mailto:gdal-dev-bounces at lists.osgeo.org] On Behalf Of Frank Warmerdam
Sent: Wednesday, March 05, 2008 2:40 PM
To: Michael Workman
Cc: gdal-dev at lists.osgeo.org
Subject: [gdal-dev] Re: GDAL 1.5.0 is slow

Michael Workman wrote:
> Frank
> 
> Was able to fix my 64 bit problem by adding /usr/lib64 to my LD_LIBRARY_PATH. 
> Compiles and links fine now. Onward to other issues.
> 
> I am having problems with the time it takes to run GDAL apps. For example, there 
> are a number of versions of gdalinfo on my system. A few:
> 
>     ~> <FWTools-2.0>/bin_safe/gdalinfo --version
>     GDAL 1.5dev, FWTools 2.0.0, released 2007/11/12
>     ~> <gdal-1.5.0>/apps/gdalinfo --version
>     GDAL 1.5.0, released 2007/12/18
>     ~> /usr/local/bin/gdalinfo --version
>     GDAL 1.3.2.0, released 2006/05/02
> 
> When I am in a directory with a huge number of NITF files and run the gdalinfo 
> v1.5 versions on a single filename, it takes one to two minutes to return. If I 
> run gdalinfo v1.3.2, it returns immediately. If I take that same file and place 
> it by itself under my home directory, All three versions return quickly. I was 
> told this might have been addressed in the list before, but I have not found where.
> 
> Any ideas what is happening?

Mike,

This is:

   http://trac.osgeo.org/gdal/ticket/2158

For reasons that are not clear to me, scanning the list of files in
a directory with a lot of files is inordinately expensive in some
situations.  There is a patch that allows working around this problem
though I have yet to make a final decision on what to do about it.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org

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