Re: [I] [C++][Compute] Hash aggregation is slowish [arrow]

["pitrou (via GitHub)" <gi...@apache.org>]

pitrou commented on issue #45741:
URL: https://github.com/apache/arrow/issues/45741#issuecomment-2713540047

   For the record, Pandas is slower, but not astonishingly so either:
   * 10000 groups
   ```pycon
   >>> n = 10000
   >>> a = pa.table({'group': list(range(n))*2, 'key': ['h']*n+['w']*n, 'value': range(n*2)})
   >>> df = a.to_pandas()
   >>> %timeit df.groupby('group').sum('value')
   906 μs ± 406 ns per loop (mean ± std. dev. of 7 runs, 1,000 loops each)
   ```
   * 100000 groups
   ```pycon
   >>> n = 100000
   >>> a = pa.table({'group': list(range(n))*2, 'key': ['h']*n+['w']*n, 'value': range(n*2)})
   >>> df = a.to_pandas()
   >>> %timeit df.groupby('group').sum('value')
   6.76 ms ± 10.6 μs per loop (mean ± std. dev. of 7 runs, 100 loops each)
   ```
   


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