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[netCDF #DFM-455316]: Looks like a bug in the netCDF NC_64BIT_OFFSET variables

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  • Subject: [netCDF #DFM-455316]: Looks like a bug in the netCDF NC_64BIT_OFFSET variables
  • Date: Wed, 14 Apr 2010 15:17:14 -0600
> Hello,
> 
> This looks like a bug in the NC_64BIT_OFFSET big variable handling.
> 
> I have a test here that creates 3000* 1000 * 2000 float variable, 24 GB
> 
> After nc_enddef, the file size is suspiciously 4 GB
> 
> After writing the data, the size is 16.0 GB (17,184,000,120 bytes),
> instead of 24 GB.
> 
> Reading fails to produce expected results at strange offset 0, 516, 704
> 
> I attached my version netcdf/nc_test/nc_test.c, it has a new function
> test_big_cube_without_unlimited_dim().
> It should be easy to copy that over and run it.
> 
> Runs very slowly, since it creates 24 GB dummy data.
> 
> Kari
> 
> 

Howdy Kari!

Looks like you found a bug of some kind. I have reproduced your problem in the 
netCDF build with new test libsrc4/tst_large2.c.

Now we will work on a fix. I will let you know when we have it. Meanwhile, as a 
workaround, I note that the NC_NETCDF4 format works fine for your test program.

If you are going to use netCDF-4, make sure you get the HDF5-1.8.4-patch1 
release, and the recent 4.1.1 release of netcdf.

Thanks,

Ed


Ticket Details
===================
Ticket ID: DFM-455316
Department: Support netCDF
Priority: Normal
Status: Open