html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/2554#issuecomment-455351725,https://api.github.com/repos/pydata/xarray/issues/2554,455351725,MDEyOklzc3VlQ29tbWVudDQ1NTM1MTcyNQ==,40218891,2019-01-17T22:13:52Z,2019-01-17T22:13:52Z,NONE,After upgrading to anaconda python 3.7 the code works without crashes. I think this issue can be closed.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634
https://github.com/pydata/xarray/issues/2554#issuecomment-439281383,https://api.github.com/repos/pydata/xarray/issues/2554,439281383,MDEyOklzc3VlQ29tbWVudDQzOTI4MTM4Mw==,40218891,2018-11-16T04:50:43Z,2018-11-16T04:50:43Z,NONE,"The error
`RuntimeError: NetCDF: Bad chunk sizes.`
is unrelated to the original problem with segv crashes. It is caused by a bug in netcdf4 C library. It is fixed in the latest version 4.6.1. As of yesterday, the newest netcdf4-python manylinux wheel contains an older version. The solution is to build netcdf4-python from source.

The segv crashes occur with other datasets as well. Example test set I used:

```for year in range(2000, 2005):
    file = '/tmp/dx{:d}.nc'.format(year)
    #times = pd.date_range('{:d}-01-01'.format(year), '{:d}-12-31'.format(year), name='time')
    times = pd.RangeIndex(year, year+300, name='time')
    v = np.array([np.random.random((32, 32)) for i in range(times.size)])
    dx = xr.Dataset({'v': (('time', 'y', 'x'), v)}, {'time': times})
    dx.to_netcdf(file, format='NETCDF4', encoding={'time': {'chunksizes': (1024,)}},
                 unlimited_dims='time')
```

A simple fix is to change  the scheduler as I did in my original post.

","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634
https://github.com/pydata/xarray/issues/2554#issuecomment-437647881,https://api.github.com/repos/pydata/xarray/issues/2554,437647881,MDEyOklzc3VlQ29tbWVudDQzNzY0Nzg4MQ==,40218891,2018-11-11T06:50:22Z,2018-11-11T06:50:22Z,NONE,I meant at random points during execution. The script crashed every time.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634
https://github.com/pydata/xarray/issues/2554#issuecomment-437647777,https://api.github.com/repos/pydata/xarray/issues/2554,437647777,MDEyOklzc3VlQ29tbWVudDQzNzY0Nzc3Nw==,40218891,2018-11-11T06:47:47Z,2018-11-11T06:47:47Z,NONE,"[soundings.zip](https://github.com/pydata/xarray/files/2569126/soundings.zip)

I did some further tests, the crash occurs somewhat randomly.

","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634
https://github.com/pydata/xarray/issues/2554#issuecomment-437646885,https://api.github.com/repos/pydata/xarray/issues/2554,437646885,MDEyOklzc3VlQ29tbWVudDQzNzY0Njg4NQ==,40218891,2018-11-11T06:22:27Z,2018-11-11T06:22:27Z,NONE,"About 600k for 2 files. I could spend some time to try size that down, but if there is a way to upload the the whole set it would be easier for me.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634
https://github.com/pydata/xarray/issues/2554#issuecomment-437633544,https://api.github.com/repos/pydata/xarray/issues/2554,437633544,MDEyOklzc3VlQ29tbWVudDQzNzYzMzU0NA==,40218891,2018-11-11T00:38:03Z,2018-11-11T00:38:03Z,NONE,"Another puzzle, I don't know it is related to the crashes.
 
Trying to localize the issue I added line after `else` on line 453 in netCDF4_.py:
`print('=======', name, encoding.get('chunksizes'))`

`ds0 = xr.open_dataset('/tmp/nam/bufr.701940/bufr.701940.2010123112.nc')`
`ds0.to_netcdf('/tmp/d0.nc')`

This prints:
```
======= hlcy (1, 85)
======= cdbp (1, 85)
======= hovi (1, 85)
======= itim (1024,)

---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-5-aeb92962e874> in <module>()
      1 ds0 = xr.open_dataset('/tmp/nam/bufr.701940/bufr.701940.2010123112.nc')
----> 2 ds0.to_netcdf('/tmp/d0.nc')

/usr/local/Python-3.6.5/lib/python3.6/site-packages/xarray/core/dataset.py in to_netcdf(self, path, mode, format, group, engine, encoding, unlimited_dims, compute)
   1220                          engine=engine, encoding=encoding,
   1221                          unlimited_dims=unlimited_dims,
-> 1222                          compute=compute)
   1223 
   1224     def to_zarr(self, store=None, mode='w-', synchronizer=None, group=None,

/usr/local/Python-3.6.5/lib/python3.6/site-packages/xarray/backends/api.py in to_netcdf(dataset, path_or_file, mode, format, group, engine, encoding, unlimited_dims, compute, multifile)
    718         # to be parallelized with dask
    719         dump_to_store(dataset, store, writer, encoding=encoding,
--> 720                       unlimited_dims=unlimited_dims)
    721         if autoclose:
    722             store.close()

/usr/local/Python-3.6.5/lib/python3.6/site-packages/xarray/backends/api.py in dump_to_store(dataset, store, writer, encoder, encoding, unlimited_dims)
    761 
    762     store.store(variables, attrs, check_encoding, writer,
--> 763                 unlimited_dims=unlimited_dims)
    764 
    765 

/usr/local/Python-3.6.5/lib/python3.6/site-packages/xarray/backends/common.py in store(self, variables, attributes, check_encoding_set, writer, unlimited_dims)
    264         self.set_dimensions(variables, unlimited_dims=unlimited_dims)
    265         self.set_variables(variables, check_encoding_set, writer,
--> 266                            unlimited_dims=unlimited_dims)
    267 
    268     def set_attributes(self, attributes):

/usr/local/Python-3.6.5/lib/python3.6/site-packages/xarray/backends/common.py in set_variables(self, variables, check_encoding_set, writer, unlimited_dims)
    302             check = vn in check_encoding_set
    303             target, source = self.prepare_variable(
--> 304                 name, v, check, unlimited_dims=unlimited_dims)
    305 
    306             writer.add(source, target)

/usr/local/Python-3.6.5/lib/python3.6/site-packages/xarray/backends/netCDF4_.py in prepare_variable(self, name, variable, check_encoding, unlimited_dims)
    466                 least_significant_digit=encoding.get(
    467                     'least_significant_digit'),
--> 468                 fill_value=fill_value)
    469             _disable_auto_decode_variable(nc4_var)
    470 

netCDF4/_netCDF4.pyx in netCDF4._netCDF4.Dataset.createVariable()

netCDF4/_netCDF4.pyx in netCDF4._netCDF4.Variable.__init__()

netCDF4/_netCDF4.pyx in netCDF4._netCDF4._ensure_nc_success()

RuntimeError: NetCDF: Bad chunk sizes.
```

The dataset is:

```
<xarray.Dataset>
Dimensions:  (dim_1: 1, dim_prof: 60, dim_slyr: 4, ftim: 85, itim: 1)
Coordinates:
  * ftim     (ftim) timedelta64[ns] 00:00:00 01:00:00 ... 3 days 12:00:00
  * itim     (itim) datetime64[ns] 2010-12-31T12:00:00
Dimensions without coordinates: dim_1, dim_prof, dim_slyr
Data variables:
    stnm     (dim_1) float64 ...
    rpid     (dim_1) object ...
    clat     (dim_1) float32 ...
    clon     (dim_1) float32 ...
    gelv     (dim_1) float32 ...
    clss     (itim, ftim) float32 ...
    pres     (itim, ftim, dim_prof) float32 ...
    tmdb     (itim, ftim, dim_prof) float32 ...
    uwnd     (itim, ftim, dim_prof) float32 ...
    vwnd     (itim, ftim, dim_prof) float32 ...
    spfh     (itim, ftim, dim_prof) float32 ...
    omeg     (itim, ftim, dim_prof) float32 ...
    cwtr     (itim, ftim, dim_prof) float32 ...
    dtcp     (itim, ftim, dim_prof) float32 ...
    dtgp     (itim, ftim, dim_prof) float32 ...
    dtsw     (itim, ftim, dim_prof) float32 ...
    dtlw     (itim, ftim, dim_prof) float32 ...
    cfrl     (itim, ftim, dim_prof) float32 ...
    tkel     (itim, ftim, dim_prof) float32 ...
    imxr     (itim, ftim, dim_prof) float32 ...
    pmsl     (itim, ftim) float32 ...
    prss     (itim, ftim) float32 ...
    tmsk     (itim, ftim) float32 ...
    tmin     (itim, ftim) float32 ...
    tmax     (itim, ftim) float32 ...
    wtns     (itim, ftim) float32 ...
    tp01     (itim, ftim) float32 ...
    c01m     (itim, ftim) float32 ...
    srlm     (itim, ftim) float32 ...
    u10m     (itim, ftim) float32 ...
    v10m     (itim, ftim) float32 ...
    th10     (itim, ftim) float32 ...
    q10m     (itim, ftim) float32 ...
    t2ms     (itim, ftim) float32 ...
    q2ms     (itim, ftim) float32 ...
    sfex     (itim, ftim) float32 ...
    vegf     (itim, ftim) float32 ...
    cnpw     (itim, ftim) float32 ...
    fxlh     (itim, ftim) float32 ...
    fxlp     (itim, ftim) float32 ...
    fxsh     (itim, ftim) float32 ...
    fxss     (itim, ftim) float32 ...
    fxsn     (itim, ftim) float32 ...
    swrd     (itim, ftim) float32 ...
    swru     (itim, ftim) float32 ...
    lwrd     (itim, ftim) float32 ...
    lwru     (itim, ftim) float32 ...
    lwrt     (itim, ftim) float32 ...
    swrt     (itim, ftim) float32 ...
    snfl     (itim, ftim) float32 ...
    smoi     (itim, ftim) float32 ...
    swem     (itim, ftim) float32 ...
    n01m     (itim, ftim) float32 ...
    r01m     (itim, ftim) float32 ...
    bfgr     (itim, ftim) float32 ...
    sltb     (itim, ftim) float32 ...
    smc1     (itim, ftim, dim_slyr) float32 ...
    stc1     (itim, ftim, dim_slyr) float32 ...
    lsql     (itim, ftim) float32 ...
    lcld     (itim, ftim) float32 ...
    mcld     (itim, ftim) float32 ...
    hcld     (itim, ftim) float32 ...
    snra     (itim, ftim) float32 ...
    wxts     (itim, ftim) float32 ...
    wxtp     (itim, ftim) float32 ...
    wxtz     (itim, ftim) float32 ...
    wxtr     (itim, ftim) float32 ...
    ustm     (itim, ftim) float32 ...
    vstm     (itim, ftim) float32 ...
    hlcy     (itim, ftim) float32 ...
    cdbp     (itim, ftim) float32 ...
    hovi     (itim, ftim) float32 ...
Attributes:
    model:    Unknown
```



","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634
https://github.com/pydata/xarray/issues/2554#issuecomment-437631073,https://api.github.com/repos/pydata/xarray/issues/2554,437631073,MDEyOklzc3VlQ29tbWVudDQzNzYzMTA3Mw==,40218891,2018-11-10T23:49:22Z,2018-11-10T23:49:22Z,NONE,"No, it works fine.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,379472634