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/5290#issuecomment-845604377,https://api.github.com/repos/pydata/xarray/issues/5290,845604377,MDEyOklzc3VlQ29tbWVudDg0NTYwNDM3Nw==,1217238,2021-05-21T02:22:15Z,2021-05-21T02:22:15Z,MEMBER,"> The (potentially very large) coordinate still needs to fit in memory though... either when creating the dummy zarr store (which could be done differently) or when opening it. Is that correct?

This is correct

> That wont work for my use case when the coordinate is very large. Do you know an alternative? Would it help if I store the coordinate with a non-dimension name?

Yes, this would work.

We do probably want to change this behavior in the future as part of the changes related to https://github.com/pydata/xarray/issues/1603, e.g., to support out of core indexing. See also https://github.com/pydata/xarray/blob/master/design_notes/flexible_indexes_notes.md","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,887711474
https://github.com/pydata/xarray/issues/5290#issuecomment-839069111,https://api.github.com/repos/pydata/xarray/issues/5290,839069111,MDEyOklzc3VlQ29tbWVudDgzOTA2OTExMQ==,1217238,2021-05-11T19:45:01Z,2021-05-11T19:45:37Z,MEMBER,"Hi @niowniow thanks for the feedback and code example here. I've been refactoring the Zarr region re-write functionality in https://github.com/pydata/xarray/pull/5252 so your feedback is timely.

It might be worth trying the code in that PR to see if it changes anything, but in the best case I suspect it would just give you a different error message.

To clarify:
- Writing to a region requires that all the desired variables already exist in the Zarr store (e.g., via `to_zarr()` with `compute=False`). The main point of writing to a region is that it should be safe to do in parallel, which is not the case for creating new variables. So I think encountering errors in this case is expected, although I agree these error messages are not very informative!
- ""chunks in coords are not taken into account while saving!?"" is correct, but this is actually more a limitation of Xarray's current data model. Coords with the same name as their dimension are converted into an in-memory pandas.Index object -- they can't be stored as dask arrays. You actually still write the data in chunks, but you have to do it by supplying the `encoding` parameter to `to_zarr`, e.g., `ds.to_zarr(path, mode='w', encoding={'x': {'chunks': 10}}, compute=False, consolidated=True)`.

If you have any specific suggestions for where the docs might be clarified those would certainly be appreciated!","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,887711474