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[netCDFJava #GCF-381402]: NetCDF Java, NetcdfFileWriteable.openExisting

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  • Subject: [netCDFJava #GCF-381402]: NetCDF Java, NetcdfFileWriteable.openExisting
  • Date: Mon, 17 Sep 2012 13:32:59 -0600
thanks for reminding, i just ran program on windose 7 and got:

      10 vars:  0.0007 sec, 0.000068 sec/var
    1000 vars:  0.0291 sec, 0.000029 sec/var
   10000 vars:  0.7798 sec, 0.000078 sec/var
   50000 vars: 35.5216 sec, 0.000710 sec/var

the last one seems to indicate a n^2 effect, probably a linear lookup.

however, creating 50000 vars is not what netcdf-3 was designed for. is this a 
real use case?

john

> Hi John,
> I'd like to send you the test program regarding ticket GCF-381402 again.
> I hope that you can find time to have a look,
> why NetcdfFileWriteable.openExisting needs so much time for files with many
> variables.
> Thanks,
> Bernd
> 
> 
> address@hidden> wrote:
> 
> > Hi Bernd:
> >
> > Can you send me the test program so that i can reproduce? thanks
> >
> > John
> >
> > > Hello NetCDF Java,
> > >
> > > I am testing the usage of NetCDF Java 4.3 to write NetCDF-3 files.
> > > I have chosen NetCDF Java for the test because the Files will be written
> > > from Windows and Linux.
> > >
> > > Theses Files contain many 3D-float-Arrays and need many updates during
> > > their lifetime, both adding new arrays and updating the data of these.
> > > It works well so far, but NetcdfFileWriteable.openExisting does not
> > > scale well, please, see the results below.
> > >
> > > I have expected an open call without any overhead from my NetCDF
> > > experience in Perl and R.
> > >
> > > What is the reason, is there a workaround ?
> > >
> > > Thanks,
> > > Bernd
> > >
> > > NetcdfFileWriteable.openExisting:  2967 vars =>   0.750 sec, 0.0003
> > sec/var
> > > NetcdfFileWriteable.openExisting:  3625 vars =>   1.484 sec, 0.0004
> > sec/var
> > > NetcdfFileWriteable.openExisting: 15541 vars =>  28.781 sec, 0.0019
> > sec/var
> > > NetcdfFileWriteable.openExisting: 51457 vars => 310.478 sec, 0.0060
> > sec/var
> > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: GCF-381402
> > Department: Support netCDF Java
> > Priority: Normal
> > Status: Open
> >
> >
> 
> 

Ticket Details
===================
Ticket ID: GCF-381402
Department: Support netCDF Java
Priority: High
Status: Open