id,node_id,number,state,locked,title,user,body,created_at,updated_at,closed_at,merged_at,merge_commit_sha,assignee,milestone,draft,head,base,author_association,auto_merge,repo,url,merged_by
1222373733,PR_kwDOAMm_X85I2_Fl,7494,closed,0,Update contains_cftime_datetimes to avoid loading entire variable array,5179430,"- [x] Closes #7484
- [x] User visible changes (including notable bug fixes) are documented in `whats-new.rst`

This PR greatly improves the performance for opening datasets with large arrays of object type (typically string arrays) since `contains_cftime_datetimes` was triggering the entire array to be read from the file just to check the very first element in the entire array.

@Illviljan continuing our discussion from the issue thread, I did try to pass in `var._data` to `_contains_cftime_datetimes`, but I had a lot of trouble finding a way to generalize how to index the first array element. The best I could do was `var._data.array.get_array()`, but I don't think `get_array` is implemented for every backend. So for now I am leaving my original proposed solution.",2023-01-30T21:54:35Z,2023-03-07T16:22:24Z,2023-03-07T16:10:30Z,2023-03-07T16:10:30Z,798f4d492b7f87172a50a00cf7c4c68e4cbb8b4e,,,0,62ce6e1a138cf594269c2b55460c2015d9610e08,830ee6de0d545c997df84fe69b0ac2334bde1d1b,CONTRIBUTOR,,13221727,https://github.com/pydata/xarray/pull/7494,