dask / dask-expr

BSD 3-Clause "New" or "Revised" License
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Add `how="leftanti"` support for cudf-backed merge #1073

Open charlesbluca opened 1 month ago

charlesbluca commented 1 month ago

Looks like we should unblocked to support left anti joins when dataframe.backend="cudf", similar to the case in legacy Dask dataframe:

https://github.com/dask/dask/blob/df4de6ea53054790b09006c8ea68ef8725d39025/dask/dataframe/multi.py#L565

Note that like the legacy code, we'll fail somewhere down in the comptutation stack if we try this on CPU - not sure if it makes sense to check the backend if how="leftanti" and eagerly raise a NotImplementedError if dataframe.backend != "cudf".

cc @rjzamora