Hi,
I am working on a European project Micore for which I setup an opendap
server. I am experiencing some performance issues.
I tried using the toolsUI-2.2.22.jar with mexnc and matlab to access data
and noticed that for every request it takes about 10 seconds to call a
function.
Also when I used the toolsUI as a ui and tried using the ncdump function it
took about 10 seconds for it to return.
Using wireshark I stored the connection information which contains the
following information:
after 0.2 seconds:
GET /opendap/rijkswaterstaat/jarkus/transect.nc.dds HTTP/1.1
returns after 0.21 seconds with HTTP OK and dimensions
after 0.22 seconds:
GET /opendap/rijkswaterstaat/jarkus/transect.nc.das HTTP/1.1
returns after 0.23 seconds with HTTP OK and attributes
after 0.24 seconds:
GET /opendap/rijkswaterstaat/jarkus/transect.nc.dods?areaname,year HTTP/1.1
after 10 seconds returns with HTTP OK and a lot of data
So what happens:
0.25 seconds is spend enquiring the information needed for the ncdump
output.
10 seconds is spend on reading some variables, information which is not
needed
The site I tried this with is
http://micore.wldelft.nl/opendap/rijkswaterstaat/jarkus/transect.nc.html
I also found the same behaviour though with different variables on another
site I tried:
http://penguin.sfos.uaf.edu/opendap/FNMOC/sst/nc/200810/sst_2008102406.nc.bz2.html
toolsUI-4.0 gives the same results
Is anyone experiencing similar behaviour?
Can I assume this to be an error?
If it is an error in which source code (version 2.2.22 or 4.0 or svn?)
should it be fixed?
Can anyone suggest a way to speed up my queries to the opendap server if
this is expected behaviour?
Thanks,
Fedor Baart
