On Sun, 18 Mar 2018, Ouwen Huang wrote:
I feel quite silly, but it seems that the `gdal.Open` was actually opening
the file from the docker mounted NFS, just very slowly. I left it to run
for 2 minutes or so and it returned.
But this is weird behavior because on the host a `*Dataset` was returned
instantly, and within the docker container running `cp
/mnt/efs/<my_geo.tiff> <docker_local_dir` is also instant. The 2min
latency seems to only occur within a docker mounted network filesystem for
the `gdal.Open` command.
Some other findings, the `/mnt/efs/` directory i'm using has several files
(100k+). When I move the geotiff under a new directory within EFS
(`mnt/efs/test`), the `gdal.Open` command is instant within the docker
container.
Is there a reason why `gdal.Open` is slow for a cluttered directory but
unix `cp` is not?
http://www.gdal.org/classGDALOpenInfo.html
talks about "sibling" files; that is other files in the same directory.
These are opened at the same time for some reason.
https://trac.osgeo.org/gdal/ticket/2158 suggests that the environment
variable GDAL_DISABLE_READDIR_ON_OPEN should disable this.
--
Andrew C. Aitchison Cambridge, UK
and...@aitchison.me.uk
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