issues: 1778486450

This data as json

id node_id number title user state locked assignee milestone comments created_at updated_at closed_at author_association active_lock_reason draft pull_request body reactions performed_via_github_app state_reason repo type
1778486450 PR_kwDOAMm_X85UHfL4 7948 Implement preferred_chunks for netcdf 4 backends 167802 closed 0     10 2023-06-28T08:43:30Z 2023-09-12T09:01:03Z 2023-09-11T23:05:49Z CONTRIBUTOR   0 pydata/xarray/pulls/7948

According to the open_dataset documentation, using chunks="auto" or chunks={} should yield datasets with variables chunked depending on the preferred chunks of the backend. However neither the netcdf4 nor the h5netcdf backend seem to implement the preferred_chunks encoding attribute needed for this to work.

This PR adds this attribute to the encoding upon data reading. This results in chunks="auto" in open_dataset returning variables with chunk sizes multiples of the chunks in the nc file, and for chunks={}, returning the variables with then exact nc chunk sizes.

  • [x] Closes #1440
  • [x] Tests added
  • [ ] User visible changes (including notable bug fixes) are documented in whats-new.rst
  • [ ] New functions/methods are listed in api.rst
 
{
    "url": "https://api.github.com/repos/pydata/xarray/issues/7948/reactions",
    "total_count": 0,
    "+1": 0,
    "-1": 0,
    "laugh": 0,
    "hooray": 0,
    "confused": 0,
    "heart": 0,
    "rocket": 0,
    "eyes": 0
}
     13221727 pull

Links from other tables