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/3795#issuecomment-590375940,https://api.github.com/repos/pydata/xarray/issues/3795,590375940,MDEyOklzc3VlQ29tbWVudDU5MDM3NTk0MA==,34353851,2020-02-24T15:21:42Z,2020-02-24T15:26:57Z,NONE,"df1=xarray.open_mfdataset plus parallel=True
df1=df1.rename({'__xarray_dataarray_variable__':'v'})

The chunksize changes to 365 and the dataset creates inside a Datarray of 365, not the global size which is 14610. [xarray.Dataset('u':df1,'v'df2)]

df2 same operation

Pseudo Solution for me.
xarray.Dataset({'u':df1.u.chunk(14610),'v':df2.v.chunk(14610)},coords={'time':time_Index,'latitude':latitude_Index,'longitude':longitude_Index,'level':level_Index})","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,569806418
https://github.com/pydata/xarray/issues/3795#issuecomment-590351872,https://api.github.com/repos/pydata/xarray/issues/3795,590351872,MDEyOklzc3VlQ29tbWVudDU5MDM1MTg3Mg==,34353851,2020-02-24T14:39:11Z,2020-02-24T15:06:16Z,NONE,"

backends\api.py
DATAARRAY_NAME = ""__xarray_dataarray_name__""
DATAARRAY_VARIABLE = ""__xarray_dataarray_variable__""

The name is auto when i open the file ,xarrray.open_dataset( parallel=True)

 core\dataarray.py

 def rename(
        self,
        new_name_or_name_dict: Union[Hashable, Mapping[Hashable, Hashable]] = None,
        **names: Hashable,
    ) -> ""DataArray"":


        if names or utils.is_dict_like(new_name_or_name_dict):
            new_name_or_name_dict = cast(
                Mapping[Hashable, Hashable], new_name_or_name_dict
            )
            name_dict = either_dict_or_kwargs(new_name_or_name_dict, names, ""rename"")
            **dataset = self.**_to_temp_dataset()**.rename(name_dict)
            return self._from_temp_dataset(dataset)**
        else:
            new_name_or_name_dict = cast(Hashable, new_name_or_name_dict)
            return self._replace(name=new_name_or_name_dict)

I think  an operation changing the previous chunksize or something with xarrray.open_dataset parallel=True, (core\parallel.py) because the chunksize changes to 365 based on days of the year
Sorry i cannot help more.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,569806418
https://github.com/pydata/xarray/issues/3795#issuecomment-590297372,https://api.github.com/repos/pydata/xarray/issues/3795,590297372,MDEyOklzc3VlQ29tbWVudDU5MDI5NzM3Mg==,34353851,2020-02-24T12:30:34Z,2020-02-24T12:30:34Z,NONE,"After i modify again the chunksize to 365 to avoid the Memory Error
<xarray.Dataset>
Dimensions:    (latitude: 68, level: 47, longitude: 81, time: 14610)
Data variables:
    u          (time, level, latitude, longitude) float32 dask.array<shape=(14610, 47, 68, 81), chunksize=(365, 47, 68, 81)>
    v          (time, level, latitude, longitude) float32 dask.array<shape=(14610, 47, 68, 81), chunksize=(365, 47, 68, 81)>","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,569806418
https://github.com/pydata/xarray/issues/3795#issuecomment-590294555,https://api.github.com/repos/pydata/xarray/issues/3795,590294555,MDEyOklzc3VlQ29tbWVudDU5MDI5NDU1NQ==,34353851,2020-02-24T12:21:39Z,2020-02-24T12:21:39Z,NONE,"The strange is the DataArray chunksize changes after i modify the name '__xarray_dataarray_variable__' to use another to the Dataset. 

<xarray.Dataset>
Dimensions:    (latitude: 68, level: 47, longitude: 81, time: 14610)
Data variables:
    u          (time, level, latitude, longitude) float32 dask.array<shape=(14610, 47, 68, 81), chunksize=(14610, 47, 68, 81)>
    v          (time, level, latitude, longitude) float32 dask.array<shape=(14610, 47, 68, 81), chunksize=(14610, 47, 68, 81)>","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,569806418