issues: 2159328369

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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
2159328369 I_kwDOAMm_X86AtLxx 8793 `.fillna()` slower than expected for sparse data arrays with `fill_value=nan` 13053829 open 0     1 2024-02-28T16:14:10Z 2024-02-28T16:14:15Z   CONTRIBUTOR      

What is your issue?

Expected behavior

.fillna(0) should be near instantaneous when applied to a sparse DataArray with fill_value=nan

Why

.fillna(0) only needs to update the fill_value to 0.

Current behaviour

The normal .where() operation is applied on the DataArray instead of using the shortcut described above.

Question

What would be required to improve the performance of fillna()? I'm happy to try taking a stab at it if pointed in the right direction.

 
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     13221727 issue

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